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['Wang, Xin', 'Lough, Cody S.', 'Bristow, Douglas A.', 'Landers, Robert G.', 'Kinzel, Edward C.']
2021-11-09T14:51:33Z
2021-11-09T14:51:33Z
2018
Mechanical Engineering
null
['https://hdl.handle.net/2152/90086', 'http://dx.doi.org/10.26153/tsw/17007']
eng
2018 International Solid Freeform Fabrication Symposium
Open
['spatial sampling resolution', 'thermal camera', 'temperature monitoring', 'feature extracts', 'selective laser melting']
Effects of Thermal Camera Resolution on Feature Extraction in Selective Laser Melting
Conference paper
https://repositories.lib.utexas.edu//bitstreams/043033c9-f7d8-46b5-85b0-4e6f506e2e8d/download
University of Texas at Austin
Selective Laser Melting (SLM) is a common additive manufacturing process which uses a laser energy source to fuse metal powder layer by layer. Engineering properties and microstructure are related to the part’s thermal history. It is important to measure the thermal history in-situ to qualify parts and provide the sensing which is necessary for process control. A common measurement tool for this purpose is a thermal camera that records the thermal emission of the part’s surface. This study investigates the effects of spatial sampling resolution of thermal cameras when monitoring the temperature in SLM processes. High-fidelity simulation of an SLM process is used to quantify the effects of the camera’s sampling in space. Next, the effect that spatial resolutions have on feature extraction, namely peak temperature and melt pool morphology, is investigated by applying feature extraction methodologies to the down-sampled simulation data. Finally, some methods of refining the down-sampled data are applied and their effects are discussed.
null
null
null
null
null
null
['Soltani-Tehrani, Arash', 'Lee, Seungjong', 'Sereshk, Mohammad Reza Vaziri', 'Shamsaei, Nima']
2021-11-30T21:39:12Z
2021-11-30T21:39:12Z
2019
Mechanical Engineering
null
['https://hdl.handle.net/2152/90558', 'http://dx.doi.org/10.26153/tsw/17477']
eng
2019 International Solid Freeform Fabrication Symposium
Open
['lattice structures', 'laser beam powder bed fusion', 'LB-PBF', 'stainless steels', 'stiffness', 'bone implants']
Effects of Unit Cell Size on the Mechanical Performance of Additive Manufactured Lattice Structures
Conference paper
https://repositories.lib.utexas.edu//bitstreams/1e0cf212-2864-489f-a937-fe9f85515878/download
University of Texas at Austin
Lattice structures are generated through the repetition of smaller structures, defined as unit cells. These structures are popular alternatives for bone implants due to the potential to adjust the stiffness. However, in some applications, there are volume and mass constraints that cannot be exceeded. Therefore, to match the lattice structure’s stiffness to that of the natural bone, unit cell sizes should be altered. In this study, the effects of different unit cell sizes, on the compression behavior of lattice structures fabricated from 316L stainless steel (SS) via laser beam powder bed fusion (LB-PBF) are studied through finite element analysis (FEA) while the volume and mass are kept constant and results of which, are validated by experiments. It was found that energy absorption capability and stiffness of lattice structures can increase with decreasing the size while the volume and mass are kept constant. The lattice structure with smaller unit cell dimensions tolerated a relatively higher maximum force for the same amount of displacement.
null
null
null
null
null
null
['Snelling, Dean', 'Blount, Heather', 'Forman, Charles', 'Ramsburg, Kelly', 'Wentzel, Andrew', 'Williams, Christopher', 'Druschitz, Alan']
2021-10-11T22:57:21Z
2021-10-11T22:57:21Z
2013
Mechanical Engineering
null
['https://hdl.handle.net/2152/88677', 'http://dx.doi.org/10.26153/tsw/15611']
eng
2013 International Solid Freeform Fabrication Symposium
Open
['binder jetting', 'indirect 3D printing', 'metal casting', 'sand casting']
The Effects on 3D Printed Molds on Metal Castings
Conference paper
https://repositories.lib.utexas.edu//bitstreams/dca0142c-8b06-46b6-b15e-192db2a5457b/download
University of Texas at Austin
Additive manufacture of sand molds via binder jetting enables the casting of complex metal geometries. Various material systems have been created for 3D printing of sand molds; however, a formal study of the materials’ effects on cast products has not yet been conducted. In this paper the authors investigate potential differences in material properties (microstructure, porosity, mechanical strength) of A356 – T6 castings resulting from two different commercially available 3D printing media. In addition, the material properties of cast products from traditional “no-bake” silica sand is used as a basis for comparison of castings produced by the 3D printed molds.
null
null
null
null
null
null
['Choi, S.H.', 'Zhu, W.K.']
2021-09-23T21:55:53Z
2021-09-23T21:55:53Z
9/10/08
Mechanical Engineering
null
['https://hdl.handle.net/2152/88032', 'http://dx.doi.org/10.26153/tsw/14973']
eng
2008 International Solid Freeform Fabrication Symposium
Open
['concurrent toolpaths', 'multi-material prototypes', 'layered manufacturing', 'Two-phase Overlap Query Algorithm', 'Immediate Fabrication Algorithm']
Efficient concurrent toolpath planning for multi-material layered manufacturing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/8f192b84-54d3-4985-9849-6e8e4b15e7b0/download
null
This paper proposes an algorithm for planning efficient concurrent toolpaths to reduce the build-time of fabricating multi-material prototypes by layered manufacturing. The algorithm first sorts and partitions slice contours into hierarchical families of specific materials to enhance concurrent tool movements. It then detects overlapping of parametric tool envelopes with a “Two-phase Overlap Query Algorithm” to avoid potential tool collisions. Finally, it plans concurrent movements with an “Immediate Fabrication Algorithm” (IFA) to enhance fabrication efficiency by reducing idle time of tools. The algorithm is being implemented in a multi-material virtual prototyping system. It can be adapted for control of physical fabrication of multi-material prototypes when appropriate hardware becomes available.
null
null
null
null
null
null
['Li, Fangzhi', 'Wang, Zemin', 'Zeng, Xiaoyan']
2021-11-02T13:51:52Z
2021-11-02T13:51:52Z
2017
Mechanical Engineering
null
https://hdl.handle.net/2152/89802
eng
2017 International Solid Freeform Fabrication Symposium
Open
['multi-laser beam', 'selective laser melting', 'Ti6Al4V', 'microstructure', 'mechanical property']
Efficient Fabrication of Ti6Al4V Alloy by Means of Multi-Laser Beam Selective Laser Melting
Conference paper
https://repositories.lib.utexas.edu//bitstreams/56ef7b24-2607-45f5-9e9b-c3579daeca12/download
University of Texas at Austin
A self-developed four-laser beam selective laser melting (SLM) system was used to fabricate Ti6Al4V alloy samples in this study. The relative density, micro-hardness and mechanical properties of all isolated processing areas were compared under optimized processing parameters to ensure the consistency of this system. Microstructures in overlap areas are dominated by columnar grains along the building direction and matensitic needles αˊ inclined at about ± 45° to the building direction, which are similar with those in isolated areas. Mechanical properties in overlap areas are also not inferior to those in isolated areas. The results prove the feasibility to fabricate large-scale components with a uniform microstructure and mechanical property by this SLM system. By the use of four lasers, this system can provide a high building rate of 80 cm3/h.
null
null
null
null
null
null
['Tan, S.J.', 'Zhang, X.', 'Ding, L.P.', 'Zhang, Y.C.']
2021-12-06T23:36:32Z
2021-12-06T23:36:32Z
2021
Mechanical Engineering
null
['https://hdl.handle.net/2152/90719', 'http://dx.doi.org/10.26153/tsw/17638']
eng
2021 International Solid Freeform Fabrication Symposium
Open
['layer construction', 'toolpaths', 'periodic cellular structures', 'selective laser melting']
An Efficient Layer Construction Method to Generate Accurate Printing Toolpaths of Periodic Cellular Structures for Selective Laser Melting Process
Conference paper
https://repositories.lib.utexas.edu//bitstreams/1b27d905-c662-4b70-80b3-0865c885d423/download
University of Texas at Austin
Limited by stereolithography file format, current data processing in additive manufacturing (AM) processing chain is time-consuming and has a loss of model precision in data transformation. However, both the CAD software and AM machine accept the input of more convenient and high-precision mathematical curve expressions. A predefined curved scanning pattern can be achieved in a galvanometer scanning system of selective laser melting (SLM) process, which can improve the scanning accuracy and efficiency for the shapes that can be represented by mathematical functions, e.g., circle. Therefore, this study proposes a layer construction-based method to directly generate the toolpaths for cellular structure with large file size. To demonstrate the proposed method, a case study on the toolpath generation for a flame arrestor element with a large quantity of curved fine channels, is presented. Compared with the conventional printing preparation methods, the proposed method reduces up to 90% of the total preparation time and achieves higher quality toolpaths.
null
null
null
null
null
null
['Li, C.', 'Liu, J.F.', 'Guo, Y.B.']
2021-10-26T18:26:23Z
2021-10-26T18:26:23Z
2016
Mechanical Engineering
null
https://hdl.handle.net/2152/89552
eng
2016 International Solid Freeform Fabrication Symposium
Open
['selective laser melting', 'distortion', 'multiscale simulation', 'additive manufacturing']
Efficient Multiscale Prediction of Cantilever Distortion by Selective Laser Melting
Conference paper
https://repositories.lib.utexas.edu//bitstreams/f22eaa2a-e788-40b6-8bb2-2e834b564615/download
University of Texas at Austin
Large tensile residual stress is one major issue for metal components made by selective laser melting (SLM). Residual stress is induced by non-uniform heat input, which leads to part distortion and detrimentally affects product performance. The conventional single track simulation method is not feasible to predict the distortion of a macro part since it demands an exceedingly long computational time. The coupling multiphysics phenomenon during the SLM process further complicates this issue. In this study, a temperature-thread multiscale modeling approach has been developed to predict part distortion of a twin cantilever. An equivalent body heat flux calculated from the micro scan model was imported as the “temperature-thread” to the subsequent layer hatch model. Then the hatched layer with temperature field can be used as a basic unit to build up the macro part. The temperature history and residual stress fields during the SLM process were predicted. And the distortion of twin cantilever was calculated with a reasonable accuracy compared to the experimental data.
null
null
null
null
null
null
['Xu, Nancy', 'Tutum, Cem C.']
2021-11-02T20:43:46Z
2021-11-02T20:43:46Z
2017
Mechanical Engineering
null
https://hdl.handle.net/2152/89893
eng
2017 International Solid Freeform Fabrication Symposium
Open
['surrogate-based sampling', 'selective laser sintering', 'process parameters', 'tensile strength', 'optimization']
Efficient Sampling for Design Optimization of an SLS Product
Conference paper
https://repositories.lib.utexas.edu//bitstreams/0a1e1475-d3a5-4db2-9b8b-3e22dc091ec0/download
University of Texas at Austin
In this work an efficient constrained surrogate-based sampling algorithm is implemented to optimize Selective Laser Sintering (SLS) process parameters for maximizing the tensile strength of a tensile specimen. Two variations of the algorithm have been implemented and tested on a Farsoon HT251P machine using (polyamid) PA3300 polymer powder. The algorithm is based on building a statistical predictive model of the objective response (i.e., maximization of tensile strength), aggregating the constraint function (i.e., limited amount of warping), in an iterative manner by simultaneously improving the accuracy of the predictive model as well as searching for the optimum set of process parameters. The difference in two algorithmic variations is the number of samples to update at each iteration. While the first method is based on a single sample update, the latter searches for multiple simultaneous updates to let the manufacturer try several potentially good sets of parameters in the same machine to eventually speed up the experimental evaluation procedure.
null
null
null
null
null
null
Bingham, G.A.
2021-10-05T19:00:02Z
2021-10-05T19:00:02Z
2012
Mechanical Engineering
null
['https://hdl.handle.net/2152/88409', 'http://dx.doi.org/10.26153/tsw/15348']
eng
2012 International Solid Freeform Fabrication Symposium
Open
['Additive Manufacturing', 'textile structures', '3D modeling']
Efficient Three Dimensional Modelling of Additive Manufactured Textile Structures
Conference paper
https://repositories.lib.utexas.edu//bitstreams/311c5b9b-48f2-4ebc-9f37-243be447af22/download
University of Texas at Austin
Textile structures realised by Additive Manufacturing (AM) techniques have received increasing attention during the previous decade. Due to their potential to significantly improve upon both the geometric complexity and functionality available from conventional fibre-based textiles, AM textiles present a serious opportunity to design and develop novel solutions for conventional and high-performance textile applications. AM textiles also provide the capability to produce net-shape textile artefacts and allow the development of personalised, high-performance textiles from a variety of materials currently being processed by AM technologies. While the motivation exists for the wider-scale adoption of these novel structures, practical access to an efficient three dimensional (3D) modelling strategy limits their applications. The research presented here discusses the issues surrounding the 3D modelling of complex AM textiles and discusses dedicated methodologies developed for the generation of their conformal data. The research culminates with a robust methodology for the generation of AM textile apparel data suitable for manufacture by AM techniques.
null
null
null
null
null
null
['Yuan, Mengqi', 'Bourell, David']
2021-10-06T22:47:31Z
2021-10-06T22:47:31Z
8/15/12
Mechanical Engineering
null
['https://hdl.handle.net/2152/88466', 'http://dx.doi.org/10.26153/tsw/15403']
eng
2012 International Solid Freeform Fabrication Symposium
Open
['laser sintering', 'part bed thermal gradients', 'infrared camera']
Efforts to Reduce Part Bed Thermal Gradients During Laser Sintering Processing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/8b3bdb33-a402-4aa9-932f-c82a240633c5/download
University of Texas at Austin
Part bed surface thermal gradients (x-y plane) are usually present in laser sintering (LS) fabricators. The purpose of this study was to investigate various means to reduce these thermal gradients. Several experiments were conducted using a FLIR™ infrared camera to examine the thermal profile of the part bed during the LS operation. Experiments included thermal profile characterization of the part bed with different nitrogen shielding gas flow rates, assessment of the proper experimental settings, and a temperature profile record of the part bed from the warm-up to the cool-down stage. A series of experiments were conducted using the laser as a heat source to preheat part bed surface cold spots to decrease the thermal gradients, which effect was limited by the natural low thermal conductivity of nylon 12 powder and large heat convection. Moreover, manifolds were mounted below the piston to provide warm nitrogen down draft flow during the LS operation.
null
null
null
null
null
null
['Kinsella, M. E.', 'Lilly, B.', 'Carpenter, B.', 'Cooper, K.']
2020-02-17T15:09:38Z
2020-02-17T15:09:38Z
2004
Mechanical Engineering
null
['https://hdl.handle.net/2152/80006', 'http://dx.doi.org/10.26153/tsw/7031']
eng
2004 International Solid Freeform Fabrication Symposium
Open
Static friction coefficients
Ejection Forces and Friction Coefficients from Injection Molding Experiments Using Rapid Tooling Inserts
Conference paper
https://repositories.lib.utexas.edu//bitstreams/d1279abe-2575-4659-a16e-f9d9ca9eb8b5/download
null
Experiments have been performed with injection mold inserts made using solid freeform fabrication processes in an effort to further study such applications for economic production of small quantities of parts. Static friction coefficients were determined for HDPE and HIPS against P-20 steel, sintered LaserForm ST-100, and stereolithography SL 5170 using the ASTM D 1894 standard. Injection mold inserts were constructed of the same three materials and were used to inject cylindrical parts using HDPE and HIPS. Ejection forces were measured, and a model was used to calculate ejection forces and apparent coefficients of static friction. Statistical analyses were used to determine the effects of packing time, cooling time and packing pressure on ejection force for the three insert types. This paper compares experimental and calculated ejection forces, compares standard friction test results to calculated apparent coefficients of friction, summarizes the statistical results, and comments on the feasibility of using rapid tooled inserts for injection molding.
null
null
null
null
null
null
['Jangha, Sundiata K.', 'Rosen, David W.']
2019-03-12T16:46:44Z
2019-03-12T16:46:44Z
1999
Mechanical Engineering
null
['https://hdl.handle.net/2152/73600', 'http://dx.doi.org/10.26153/tsw/742']
eng
1999 International Solid Freeform Fabrication Symposium
Open
['Injection Molding', 'Rapid Tooling']
An Ejection Mechanism Design Method for AIM Tools
Conference paper
https://repositories.lib.utexas.edu//bitstreams/9610b4bf-9e15-4b9c-ab38-d477c3b90d60/download
null
One of the key advantages of AIM tooling is time savings when producing small batch production quality parts. However, designing suitable ejection mechanisms is becoming a bottleneck. There are two goals of this paper. First, a model is presented that effectively characterizes the stresses on the mold core and part during injection molding. Second, a method is described for ejection system design. Our approach consists of a combination of analytical, computational, and physical experiments. The ejection system design method will first determine the feasibility of ejection for a particular part geometry, then will determine the number, sizes, and locations of ejector pins. Each phase of the method will be formulated into a Compromise Decision Support Problem, a multi-objective optimization problem formulation. An example will be presented to provide an idea of the robustness and the limitations of the method. Preliminary results indicate that this methodology is sound for a simple geometry.
null
null
null
null
null
null
['Mao, Q.', 'Coutris, N.', 'Fadel, G.M.']
2021-10-26T19:03:17Z
2021-10-26T19:03:17Z
2016
Mechanical Engineering
null
https://hdl.handle.net/2152/89558
eng
2016 International Solid Freeform Fabrication Symposium
Open
['elastic model', 'plastic model', 'Johnson-Cook model', 'ultrasonic additive manufacturing']
An Elasto/Plastic Model of the Ultrasonic Additive Manufacturing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/50377983-a44b-4300-a08d-7e9d1d2fde3c/download
University of Texas at Austin
Ultrasonic additive manufacturing (UAM) is a solid-state fabrication process that utilizes ultrasonic energy to bond metal foils layer by layer. It has been shown that bond formation is closely related to the plastic deformation of the material at the bonding interface. As a result, a material model is necessary to characterize the elastic and plastic deformation of material under UAM conditions. The existing material models for UAM suffer from the following issues: 1) the models are established based on experimental data of a material different from the material used in UAM. 2) The models have not fully accounted for the influential factors in UAM. Therefore, a new material model is established by modifying the Johnson-Cook model which is known to be simple but effective to capture plasticity at elevated temperature and high strain rate. The model is based on experiments carried out on aluminum 6061-T6 which has been extensively used in the ultrasonic additive manufacturing. Ultrasound-induced effects including strain hardening, strain rate hardening, acoustic softening, and thermal softening are considered in the model. In addition to plasticity, the bond formation/plastic deformation is also profoundly affected by the dynamics of the built feature which has not been considered in combination with plasticity in the existing studies. As a result, a UAM model is established in which both the mechanical and dynamic effects are taken into account. The model is shown to characterize well the plastic deformation at the bonding interface both qualitatively and quantitatively by comparing its predictions with experimental observations.
null
null
null
null
null
null
['Tate, J.S.', 'Brushaber, R.P.', 'Danielsen, E.', 'Kallagunta, H.', 'Navale, S.V.', 'Arigbabowo, O.', 'Shree, S.', 'Yaseer, A.']
2021-11-18T16:27:02Z
2021-11-18T16:27:02Z
2019
Mechanical Engineering
null
['https://hdl.handle.net/2152/90416', 'http://dx.doi.org/10.26153/tsw/17337']
eng
2019 International Solid Freeform Fabrication Symposium
Open
['annealing temperature', 'electrical properties', 'mechanical properties', 'polyamide 6', 'nanographene platelets', 'fused filament fabrication']
Electrical and Mechanical Properties of Fused Filament Fabrication of Polyamide 6 / Nanographene Filaments at Different Annealing Temperatures
Conference paper
https://repositories.lib.utexas.edu//bitstreams/5e858050-8fa0-4493-ab61-d5f281b028c3/download
University of Texas at Austin
Polyamide 6 (PA 6) nanographene composites are viable engineered nanocomposite materials with high potential for electrostatic discharge applications. This can be attributed to the ability of the nanographene particles in reducing the electrical resistivity of the parent polyamide 6 and in turn creating a conductive network for a controllable discharge of static electricity. In addition, PA 6 nanographene composites can also exploit the good mechanical properties of the parent polyamide 6, a structural thermoplastic ideal for 3D printing via fused filament fabrication (FFF). Hence, 3, 5, and 7 wt.% of NGP were blended with PA6 using co-rotating twin screw extruder to produce 1.75mm diameter for FFF using Lulzbot TAZ 6 3D printer. Scanning Electron Microscopy (SEM) was used to evaluate the degree of exfoliation of the nanographene and tensile and electrical resistivity test samples were manufactured via fused filament fabrication. The polyamide 6 nanographene composites were further subjected to annealing treatment at 80ºC, 140ºC, 200ºC and a comparison study was carried out on the observed tensile properties and electrical resistivity values of both annealed and not annealed treated.
null
null
null
null
null
null
['Bagehorn, S.', 'Wehr, J.', 'Nixon, S.', 'Balastrier, A.', 'Mertens, T.', 'Maier, H.J.']
2021-11-08T21:43:01Z
2021-11-08T21:43:01Z
2017
Mechanical Engineering
null
['https://hdl.handle.net/2152/90049', 'http://dx.doi.org/10.26153/tsw/16970']
eng
2017 International Solid Freeform Fabrication Symposium
Open
['electropolishing', '3D SurFin', 'Ti-6Al-4V', 'surface morphology', 'fatigue performance', 'laser beam melting']
Electrochemical Enhancement of the Surface Morphology and the Fatigue Performance of Ti-6Al-4V Parts Manufactured by Laser Beam Melting
Conference paper
https://repositories.lib.utexas.edu//bitstreams/f415fb8e-34d6-43f9-8d34-759df6353de0/download
University of Texas at Austin
In the course of the industrialization of the Additive Manufacturing (AM) process of metallic components, the surface finish of the final parts is a key milestone. ‘As-built’ AM surfaces feature a high initial surface roughness (i.e. Ra > 10 µm), which often exceeds the specification for technical applications. In order to apply AM for highly stressed and cyclically loaded components, the as-built surface roughness needs to be reduced. Since conventional surface finishing processes as machining or blasting often show a limited applicability to complex shaped AM parts, an enhanced electrolytic polishing process was developed (3D SurFin®). Within the present study, Ti-6Al-4V AM plates and fatigue samples were produced in a powder bed laser beam system. The enhanced electrolytic polishing process led to a significant roughness decrease of approximately 84 % for a treatment time of 60 min. Also, a notable improvement of the fatigue performance of 174 % was achieved after a treatment time of 40 min in comparison to the as-built reference samples.
null
null
null
null
null
null
['Goel, Abhishek', 'Bourell, David']
2021-09-28T20:10:09Z
2021-09-28T20:10:09Z
9/15/09
Mechanical Engineering
null
['https://hdl.handle.net/2152/88171', 'http://dx.doi.org/10.26153/tsw/15112']
eng
2009 International Solid Freeform Fabrication Symposium
Open
['room temperature infiltration', 'selective laser sintered preforms with metals', 'electrochemical deposition', 'electrochemical infiltration']
Electrochemical Infiltration of Laser Sintered Preforms with Metals
Conference paper
https://repositories.lib.utexas.edu//bitstreams/7eb14903-c1eb-4879-8409-05456042b4dd/download
University of Texas at Austin
The proposed work deals with room temperature infiltration of selective laser sintered preforms with metals. The approach adopted for carrying out room temperature infiltration was adaptation and modification of electrochemical deposition techniques. Electroless deposition and Electrolytic deposition processes were modified in order to carry out metal ion infiltration and their deposition on the walls of the interconnected pores. The electrolytic infiltration process was modified by inserting a conductive graphite cathode in the center in order to attract positive nickel ions through the interconnected porous network and hence deposit them on the walls of the pores. One of the major advantages of electrochemical infiltration is the lower processing temperature. Low temperature reduces both energy consumption and associated carbon-footprint and also minimizes undesirable structural changes. Both conductive and non-conductive preforms can be electrochemically infiltrated and MMCs produced by this method have potential for use in structural applications. This research was sponsored by the National Science Foundation, Grant DMI-0522176.
null
null
null
null
null
null
['Patel, Krish', 'McNamee, Amelia', 'Silwal, Bishal']
2021-11-18T19:04:43Z
2021-11-18T19:04:43Z
2019
Mechanical Engineering
null
['https://hdl.handle.net/2152/90470', 'http://dx.doi.org/10.26153/tsw/17391']
eng
2019 International Solid Freeform Fabrication Symposium
Open
['electroforming', 'microscale structures', 'copper', 'additive manufacturing']
Electroforming Process to Additively Manufactured Microscale Structures
Conference paper
https://repositories.lib.utexas.edu//bitstreams/3b563007-8dd7-4785-b9fd-16bcee1d3f8b/download
University of Texas at Austin
Electroforming is a metal forming process that forms parts through electrodeposition. The overall study and production of the copper mandrel were conducted by examining the growth and depth of the depositions at macroscopic levels. The study of the plating constant for a copper plate in copper sulfate was performed via the production of copper mandrels. Each mandrel was produced by performing multiple experiments and qualitatively and quantitatively examining the resultant depositions and the initial and final states of the experiment. The results were measured based on variations of current and voltage duration in the bath cycle, time duration, solution concentration, and change in mass of both the anode and cathode. The variables such as plating constant and direct current distribution are determined. It seems the rate at which the structure can be fabricated depends on the type of electrolytes used and the parts that are deposited can be scalable.
null
null
null
null
null
null
['Kircher, R.S.', 'Christensen, A.M.', 'Wurth, K.W.']
2021-09-29T14:14:26Z
2021-09-29T14:14:26Z
2009-09
Mechanical Engineering
null
['https://hdl.handle.net/2152/88178', 'http://dx.doi.org/10.26153/tsw/15119']
eng
2009 International Solid Freeform Fabrication Symposium
Open
['Electron Beam Melting', 'orthopaedic implants', 'Co-Cr-Mo Alloy']
Electron Beam Melted (EBM) Co-Cr-Mo Alloy for Orthopaedic Implant Applications
Conference paper
https://repositories.lib.utexas.edu//bitstreams/b7a308f3-1136-4256-a65b-ca162daa153d/download
University of Texas at Austin
The Electron Beam Melting (EBM) manufacturing process is emerging as an additional method for producing orthopaedic devices in several materials, including Co-Cr-Mo Alloy. This work presents the chemical, microstructural and mechanical properties of several test specimens produced by the EBM process before and after a post‐EBM Heat treatment. Comparisons are made to the properties of Co-Cr-Mo materials used within the orthopaedic implant industry processed by conventional methods such as investment casting and machining from wrought. The results of the work are promising, and demonstrate that EBM produced Co-Cr-Mo material has comparable, and in several cases superior microstructural and mechanical properties to those found in the traditionally-processed materials used today.
null
null
null
null
null
null
['Dave, V.R.', 'Matz, J.E.', 'Eagar, T.W.']
2018-10-04T19:45:04Z
2018-10-04T19:45:04Z
1995
Mechanical Engineering
doi:10.15781/T2542JT42
http://hdl.handle.net/2152/68707
eng
1995 International Solid Freeform Fabrication Symposium
Open
['Solid free-form fabrication', '3D Printing', 'SLS']
Electron Beam Solid Freeform Fabrication of Metal Parts
Conference paper
https://repositories.lib.utexas.edu//bitstreams/3d313f19-0f47-4e0e-a710-9bd3a1c3233f/download
null
A novel method for near-net-shape fabrication of large, complex metal parts without the need for specific tooling is described. Parts are built up in a layer-by-Iayer fashion by feeding raw material in wire form into a melt pool which is maintained with an electron beam. Several different alloys have been successfully deposited using a low-energy electron beam. A model has been developed which permits determination ofthe melt depth and vaporization-limited power input as functions of beam energy and travel velocity. Processing parameters obtained from experiments with low-energy electron beams can be used to predict melting behavior under the influence of higher energy beams. The process is being investigated as a possible means for manufacturing compositionally-graded components.
null
null
null
null
null
null
['Castillo, Sylvia', 'Muse, Dan', 'Medina, Frank', 'MacDonald, Eric', 'Wicker, Ryan']
2021-09-29T18:10:24Z
2021-09-29T18:10:24Z
2009-09
Mechanical Engineering
null
['https://hdl.handle.net/2152/88205', 'http://dx.doi.org/10.26153/tsw/15146']
eng
2009 International Solid Freeform Fabrication Symposium
Open
['rapid prototyping', 'stereolithography', 'direct-print', 'hybrid manufacturing', 'conformal electronics', 'accelerometer', 'three-dimensional electronics']
Electronics Integration in Conformal Substrates Fabricated with Additive Layered Manufacturing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/6ba9e9dd-93c2-42a0-b298-8f7f6279d048/download
University of Texas at Austin
A three-dimensional (3D) accelerometer sensor system with microprocessor control was fabricated using a previously developed integrated layered manufacturing system that combines conductive ink dispensing with stereolithography (SL). The electronics are integrated into a conformal substrate that is press-fit into a helmet for the purpose of detecting Traumatic Head Injury (THI) when an excessive acceleration to the head is measured. Applications include monitoring the health of soldiers or athletes. Traditional fabrication of electronics is implemented with a 2 dimensional printed circuit board (PCB), which are not well suited for rugged installations in curved locations such as the interior of a helmet. The advantage of layered manufacturing for the integration of electronics is the ability to fabricate in a conformal substrate - conforming to the curved, complex, and often flexible shapes dictated by the human body.
null
null
null
null
null
null
['Yang, L.', 'Wu, Yan', 'Lassell, Austin', 'Zhou, Bin']
2021-10-28T19:33:02Z
2021-10-28T19:33:02Z
2016
Mechanical Engineering
null
https://hdl.handle.net/2152/89677
eng
2016 International Solid Freeform Fabrication Symposium
Open
['surface treatment', 'electropolishing', 'electron beam melting', 'Ti6Al4V', 'fatigue']
Electropolishing of Ti6Al4V Parts Fabricated by Electron Beam Melting
Conference paper
https://repositories.lib.utexas.edu//bitstreams/c60caa38-d628-4f01-993b-61485f6257e2/download
University of Texas at Austin
In this study Ti6Al4V samples fabricated via electron beam melting were subjected to electropolishing under various polishing conditions using the re-designed in-house electropolishing device. The surface finish of the processed samples were characterized, and the tension-tension fatigue properties of the samples were evaluated via experimentation. The results provided preliminary information about the effect of electropolishing on surface crack initiation of the electron beam melted Ti6Al4V parts.
null
null
null
null
null
null
['Melvin, Lawrence S. III', 'Beaman, J.J.']
2018-04-17T16:56:04Z
2018-04-17T16:56:04Z
1991
Mechanical Engineering
doi:10.15781/T2NV99T6C
http://hdl.handle.net/2152/64333
eng
1991 International Solid Freeform Fabrication Symposium
Open
['Department of Mechanical Engineering', 'electrostatic powder', 'particle']
The Electrostatic Application of Powder for Selective Laser Sintering
Conference paper
https://repositories.lib.utexas.edu//bitstreams/9a4db63f-035b-4be4-93ba-999f48755882/download
null
null
null
null
null
null
null
null
['Benning, Matthew', 'Dalgarno, Kenny']
2021-10-19T15:40:40Z
2021-10-19T15:40:40Z
2014
Mechanical Engineering
null
https://hdl.handle.net/2152/89303
eng
2014 International Solid Freeform Fabrication Symposium
Open
['drop-on-demand', 'bioprinting', 'bioprinting ink', 'electrostatic stabilization', 'cationic encapsulation', 'osteosarcoma cells', 'osteosarcoma']
Electrostatic Stabilisation of Drop on Demand Bio‐Ink through the Cationic Encapsulation of Cells
Conference paper
https://repositories.lib.utexas.edu//bitstreams/cb865fdc-14fe-446c-bf77-eeb626ebeee0/download
University of Texas at Austin
The ability to formulate bioprinting inks in which suspensions of cells and other biological materials can be maintained, without affecting biological response, is crucial in producing robust printing strategies for tissue fabrication. A piezoelectrically actuated drop‐on‐demand printing system has been used to deposit electrostatically stabilised cells from a human osteosarcoma cell line (U2OS). Experiments were intended to investigate the effectiveness of a polyelectrolyte cell encapsulant to maintain cell dispersion within a bio ink. Cells were coated with a number of thicknesses of a Cationic Poly‐l‐lysine (PLL) encapsulant and their ability to release studied over 7 days, with the thinner coatings proving to be more favourable. Printing of both coated and uncoated cells indicated the dispersion and printability of coated cells was significantly better than that of uncoated cells. Preliminary results suggest that electrostatic stabilisation of bio inks could provide a solution to cell aggregation, increasing viable printing time and decreasing poor yields due to orifice obstruction.
null
null
null
null
null
null
['zur Jacobsmühlen, J.', 'Kleszczynski, S.', 'Witt, G.', 'Merhof, D.']
2021-10-20T20:48:45Z
2021-10-20T20:48:45Z
2015
Mechanical Engineering
null
https://hdl.handle.net/2152/89358
eng
2015 International Solid Freeform Fabrication Symposium
Open
['laser beam melting', 'elevated region area', 'process stability']
Elevated Region Area Measurement for Quantitative Analysis of Laser Beam Melting Process Stability
Conference paper
https://repositories.lib.utexas.edu//bitstreams/0937b043-1d46-425f-8346-1850ae393978/download
University of Texas at Austin
Laser beam melting (LBM) processes enable layer-based production of geometrically complex metallic parts with very good mechanical properties for Rapid Manufacturing. Collisions between powder coating mechanism and elevated part regions pose a major risk to process stability, which is crucial for industrial application. Minimizing elevated region area usually involves parameter tuning in a trial-and-error approach, as the process outcome is the only measure of stability. One published approach to quantifying elevated region area utilizes an imaging system, which acquires layer images of the powder bed after powder deposition and detects elevated regions using image analysis. We extend the image-based analysis to each part region, create quantitative visualizations of elevated region area for quick assessment/comparison and compute a figure of merit. In experimental build jobs with overhanging structures and different support junction parameters we gain insight into problematic part regions, which can be used as feedback in job design. The presented method helps to improve LBM process stability, which is strongly linked to process efficiency.
null
null
null
null
null
null
['Hecht, G.R.', 'Isanaka, S.P.', 'Newkirk, J.W.']
2021-11-17T23:40:29Z
2021-11-17T23:40:29Z
2019
Mechanical Engineering
null
['https://hdl.handle.net/2152/90356', 'http://dx.doi.org/10.26153/tsw/17277']
eng
2019 International Solid Freeform Fabrication Symposium
Open
['304L', 'stainless steel', 'high temperature', 'tensile strength', 'tensile elongation', 'microstructure', 'selective laser melting']
Elevated Temperature Mechanical and Microstructural Characterization of SLM SS304L
Conference paper
https://repositories.lib.utexas.edu//bitstreams/89fb67ef-c256-441a-a335-3c92523ba536/download
University of Texas at Austin
SLM built SS304L was annealed and water quenched to minimize residual stress and avoid carbide precipitation. Mini-tensile characterization of strength and elongation at temperature conditions up to 800˚ C, along with observations of the associated microstructural transformations were utilized to understand the changes produced in SLM SS304L. As-built and annealed specimens were found to exhibit decreasing strength and elongation with increasing temperature as expected. Carbide precipitates appeared after short times at high temperatures within both as-built and annealed specimens for all cases, but no brittle intermetallic phase development was observed for any of the temperatures investigated. While the lack of Sigma, Chi or Laves phases were anticipated, the premature formation of carbides is unexpected behavior for this composition of SS 304L. It is an indication of higher sensitivity of SLM made material. An additional change in the etch response was also observed between as-built and annealed specimens. It is theorized that annealing caused all ferritic and other residual phases present in as-built SLM SS 304L to fully transform into austenite. The cellular structure observed in the as-built specimen was also dissolved due to annealing and water quenching possibly leading to the strength loss observed.
null
null
null
null
null
null
['Amine, Tarak', 'Newkirk, Joseph']
2021-10-27T21:21:55Z
2021-10-27T21:21:55Z
2016
Mechanical Engineering
null
https://hdl.handle.net/2152/89618
eng
2016 International Solid Freeform Fabrication Symposium
Open
['selective laser melting', 'elevated temperatures', 'microstructural stability', '304L', 'stainless steel']
Elevated Temperature Microstructure Stability of SLM 304L Stainless Steel
Conference paper
https://repositories.lib.utexas.edu//bitstreams/b513bf9f-b48f-465f-b690-246d2330b3bd/download
University of Texas at Austin
At elevated temperatures changes in metallurgical structure can be expected for almost any steel or alloy. In stainless steels, the changes can be grain growth, carbide precipitation, ferrite decomposition, or embrittlement. These phenomena can significantly affect the properties of the stainless steel and would potentially change the functionality of the component. Therefore, the impact of elevated temperatures on the microstructure of SLM 304L stainless steel was studied. The work reported here investigates the influence of different aging times at 300C on microstructure and mechanical properties of stainless steels (304L) fabricated with the Selective Laser Melting (SLM) process. Microstructure and mechanical properties were dramatically effected at temperatures much lower than expected when compared to samples of wrought stainless steel. The stainless steel fabricated using the SLM process was more kinetically active than expected based on previous studies of 304L. Results of this study will be presented along with possible reasons for the higher activity.
null
null
null
null
null
null
['Snider, Elias B.', 'Saha, Rony Kumer', 'Dominguez, Cesar', 'Huang, Jie', 'Bristow, Douglas A.']
2024-03-26T20:45:28Z
2024-03-26T20:45:28Z
2023
Mechanical Engineering
null
['https://hdl.handle.net/2152/124404', 'https://doi.org/10.26153/tsw/51012']
en_US
2023 International Solid Freeform Fabrication Symposium
Open
['direct energy deposition', 'fiber optic sensors', 'metal', 'additive manufacturing']
Embedding Fiber Optic Sensors in Metal Components via Direct Energy Deposition
Conference paper
https://repositories.lib.utexas.edu//bitstreams/2d79748b-5005-46f2-bed0-209920e3c0b0/download
University of Texas at Austin
Fiber optics are useful as strain and temperature sensors in a variety of applications involving high-value parts. Embedding fiber optic sensors into end-use parts can allow for realtime strain and temperature monitoring of these parts in extreme conditions. Direct energy deposition processes have distinct advantages for producing parts in high-value embedded sensing applications, however, ensuring survival of the optical fiber during embedment is challenging. A method of fiber embedment using high-temperature ceramic adhesives is presented as a flexible method of embedding fiber optic sensors into end-use parts such as to preserve fiber transmission and sensor integrity. Example specimens are presented, and functionality of sensing capabilities is demonstrated.
null
null
null
null
null
null
['Stoll, Philipp', 'Mathew, Jinesh', 'Spierings, Adriaan', 'Bauer, Thomas', 'Maier, Robert R.J.', 'Wegener, Konrad']
2021-10-28T22:16:01Z
2021-10-28T22:16:01Z
2016
Mechanical Engineering
null
https://hdl.handle.net/2152/89716
eng
2016 International Solid Freeform Fabrication Symposium
Open
['fibre optical sensors', 'embedding', 'production environment', 'commercial SLM system', 'selective laser melting', 'SLM']
Embedding Fibre Optical Sensors into SLM Parts
Conference paper
https://repositories.lib.utexas.edu//bitstreams/83966afe-d07a-4b71-9b32-f872db6503b3/download
University of Texas at Austin
Selective Laser Melting (SLM) facilitates the integration of additional functionalities such as sensors into metallic parts. Such sensors can for example be embedded in sections of the parts non accessible after manufacturing. Additionally they can be positioned close to the region of interest. Depending on the type of sensor it is even possible to monitor the structural health of the part itself. This paper discusses the integration of fibre optical sensors into SLM manufactured coupons in a commercial, industry scale, SLM machine. Such systems have merely limited accessibility for fibre handling. The embedment procedure as well as the corresponding bonding quality is explained in detail. Measurement results of the embedded sensor and limitations for the embedding procedure related to the use of commercial SLM systems are presented. Additionally the need for further research is pointed out.
null
null
null
null
null
null
['Li, Xiaochun', 'Prinz, Fritz B.']
2019-09-23T16:16:29Z
2019-09-23T16:16:29Z
2000
Mechanical Engineering
null
['https://hdl.handle.net/2152/75954', 'http://dx.doi.org/10.26153/tsw/3053']
eng
2000 International Solid Freeform Fabrication Symposium
Open
Optic
Embedding of Fiber Optic Sensors in Layered Manufacturing 314
Conference paper
https://repositories.lib.utexas.edu//bitstreams/ac0bc44f-eb50-4cc3-aeed-7f170c7b036d/download
null
Layered manufacturing enables integrating sensors during production of tooling or structural components. Sensors may be placed close to the points of interest prior to enclosure. Structures with embedded sensors are capable of monitoring parameters at critical locations not accessible to ordinary sensors. This work presents a methodology for embedding fiber optic sensors in metallic structures via Shape Deposition Manufacturing. Some of the main manufacturing issues are discussed. Embedded fiber optic sensors have been employed to measure temperature and strain. Proof-of-concept experiments on a non-contact fiber optic sensing system have been performed. By implementing the remote sensing system it is possible to measure temperature and strain of rotating components exposed to potentially hostile environments such as blades in gas turbine engines.
The authors are grateful to acknowledge the financial support for this work from Office of Naval Research under the contract of N00014-96-1-0354-P00003.
null
null
null
null
null
['Zawaski, Callie', 'Margaretta, Evan', 'Stevenson, Andre', 'Pekkanen, Allison', 'Whittington, Abby', 'Long, Timothy', 'Williams, Christopher B.']
2021-11-04T18:55:45Z
2021-11-04T18:55:45Z
2017
Mechanical Engineering
null
['https://hdl.handle.net/2152/90004', 'http://dx.doi.org/10.26153/16925']
eng
2017 International Solid Freeform Fabrication Symposium
Open
['material extrusion', 'embedding', 'dissolvable materials', 'drug delivery']
Embedding of Liquids into Water Soluble Materials via Additive Manufacturing for Timed Release
Conference paper
https://repositories.lib.utexas.edu//bitstreams/f32b8904-8126-4ecd-b71c-de14c267d243/download
University of Texas at Austin
One fundamental goal of personalized medicine is to provide tailored control of the dissolution rate for an oral dosage pill. Additive manufacturing of oral dose medicine allows for customized dissolution by tailoring both geometric and printed material properties. Direct processing of medicine via filament material extrusion is challenging because many active agents become inactive at the elevated temperatures found in the melt-based process. In this work, this limitation is circumvented by incorporating the active agents via in-situ embedding into a priori designed voids. This concept of embedding active ingredients into printed parts is demonstrated by the in-situ deposition of liquid ingredients into thin-walled, water soluble, printed structures. The authors demonstrate the ability to tune dissolution time by varying the thickness of the printed parts walls using this technique.
null
null
null
null
null
null
Wasserfall, Florens
2021-10-19T18:21:52Z
2021-10-19T18:21:52Z
2015
Mechanical Engineering
null
https://hdl.handle.net/2152/89317
eng
2014 International Solid Freeform Fabrication Symposium
Open
['3D printing', 'fused deposition modeling', 'electronic circuits', 'SMD-components']
Embedding of SMD Populated Circuits into FDM Printed Objects
Conference paper
https://repositories.lib.utexas.edu//bitstreams/91536d76-9c91-4687-b2a6-02b47c0d7e3a/download
University of Texas at Austin
This paper introduces the concept of a highly integrated 3D-printing device which is capable of printing plastic parts with integrated, fully assembled electronic circuits in a single process. It is based on a standard FDM 3D-printer that has been augmented by a screw-driven conductive paste extruder for electronic circuit printing, a vacuum nozzle to pick and place SMD-components and a vision system to find and precisely align the components before placing. To control the printer, an existing host software system has been extended to synchronize the communication with the printer for interactive operations and to generate the required movements from camera data by means of image processing. A number of objects, containing circuits on both the surface and inside of the object, has been successfully printed already. Quality and durability of the generated parts have been evaluated by analyzing the curing characteristics of the conductive ink during the process and the adhesion of the components which are placed directly on the wet ink. The design concept aims for a practical, affordable approach that can be widely used by developers to lower the entrance barrier to the field of 3D-printed electronics. Hence, the hardware is kept as simple as possible, avoiding complex and expensive components as laser or CNC-milling devices, focusing on algorithmic improvements in the preprocessing and control software. All developed hard- and software-components are available under open source licenses and compatible to common existing projects.
null
null
null
null
null
null
['Turk, T.', 'Dougan, M.', 'Hendrix, L.', 'Reed, A.', 'Dominguez, C.E.', 'Suttonn, A.T.', 'Park, J.', 'Leu, M.C.']
2024-03-25T23:49:25Z
2024-03-25T23:49:25Z
2023
Mechanical Engineering
null
['https://hdl.handle.net/2152/124344', 'https://doi.org/10.26153/tsw/50952']
en_US
2023 International Solid Freeform Fabrication Symposium
Open
['lasere foil printing', 'temperature sensor', 'additive manufacturing']
EMBEDDING TEMPERATURE SENSORS WITH THE USE OF LASER-FOILPRINTING ADDITIVE MANUFACTURING
Conference paper
https://repositories.lib.utexas.edu//bitstreams/b406f1ab-b80e-45c2-810b-ca47062a8b75/download
University of Texas at Austin
Laser foil printing (LFP) is a metal additive manufacturing (AM) process using laser-based melting of metal foil technique. Using metal foils in AM has advantages over laser powder-feed processes, allowing for efficient heat transfer and resolving the drawbacks of powder-based AM such as potential powder inhalation health hazards, balling, spattering, and high powder costs. In this study, we demonstrate the advantage of LFP for embedding sensors into structures using 304L stainless-steel foil as the feed material and two different types of temperature sensors. The first type is a resistance temperature detector (RTD) platinum sensor (Pt 100), and the second type is a k-type thermocouple probe. A detailed study of the sensor embedment through LFP revealed that the spot-welding scanning strategy significantly improves the product quality than conventional line-welding scanning strategy. As a result of this study, the feasibility of fabricating functional parts with embedded sensors using the LFP process is demonstrated.
null
null
null
null
null
null
['Sih, Samuel Sumin', 'Barlow, Joel W.']
2018-11-08T15:25:31Z
2018-11-08T15:25:31Z
1995
Mechanical Engineering
doi:10.15781/T2V40KJ7S
http://hdl.handle.net/2152/69888
eng
1995 International Solid Freeform Fabrication Symposium
Open
['thermal models', 'SLS', 'emissivity']
Emissivity of Powder Beds
Conference paper
https://repositories.lib.utexas.edu//bitstreams/cf95915c-530e-4ee2-8d39-30bfeb282377/download
null
A simple model for estimating the emissivity ofthe surface of a powder bed from knowledge only ofthe bed porosity and solid emissivity is presented. Estimates by this model are compared with experimental measurements for powder beds of alumina, silicon carbide, and iron. Agreement within the uncertainty ofthe measurements, ± 10%, is obtained
null
null
null
null
null
null
['Boddu, Mallikharjuna', 'Musti, Srinivas', 'Landers, Robert G.', 'Agarwai, Sanjeev', 'Liou, Frank W.']
2019-10-18T16:14:24Z
2019-10-18T16:14:24Z
2001
Mechanical Engineering
null
['https://hdl.handle.net/2152/76250', 'http://dx.doi.org/10.26153/tsw/3339']
eng
2001 International Solid Freeform Fabrication Symposium
Open
Deposition
Empirical Modeling and Vision Based Control for Laser Aided Metal Deposition Process
Conference paper
https://repositories.lib.utexas.edu//bitstreams/93f36d78-707d-439a-ab35-59cdd97ba2aa/download
null
This paper gives a brief description of the laser aided manufacturing process. Empirical models describing the process dynamics of the laser aided metal deposition process is developed based on some of the models found in the literature. These models provide the basis for process planning and real time control. An embedded vision system, a two color temperature sensor, and a laser displacement sensor are incorporated for real time monitoring and control of the deposition process. The temperature profile of the surface and geometric characteristics of the melt pool are studied to ensure consistent operation of the process.
null
null
null
null
null
null
['Cho, Uichung', 'Wood, Kristin']
2018-12-06T22:07:17Z
2018-12-06T22:07:17Z
1997
Mechanical Engineering
doi:10.15781/T2JD4Q88T
http://hdl.handle.net/2152/71434
eng
1997 International Solid Freeform Fabrication Symposium
Open
['rapid prototyping', 'SFF']
Empirical Similitude Method for the Functional Test with Rapid Prototypes
Conference paper
https://repositories.lib.utexas.edu//bitstreams/ecd30a7a-50cc-4a76-ba42-ce59749c9cfc/download
null
Rapid prototyping has the potential to improve the performance of the design process both in cycle time and resources. Such improvements may be realized through the timely visual, ergonomic, and functional information provided by solid freeform fabrication (SFF) parts. Of these information classes, functional information is perhaps the least realized with current technology. A number of technical issues have limited functional testing of SFF parts, including sensor fusion, range of prototyping materials, part size etc. Our focus here concerns the material issues of functional testing, especially the potential differences in prototyping material choices to actual production materials. For example, to derive accurate functional information of non-polymeric products from polymeric rapid prototypes, an improved similitude method that can overcome the distortion of material characteristics is necessary. In this paper, a new similitude method that utilizes specimen test data is introduced. This method develops a mathematical transformation between prototype and product behavior through specimen testing. This transformation replaces the role ofthe scale factor of the traditional similitude method, and provides a basis for relating prototypes to proposed production parts, even under dependent loading and material conditions. Computational and experimental results of a structural design provide verification ofthe new method.
null
null
null
null
null
null
['Mehta, Priyesh', 'Berdanier, Catherine G.P.', 'Malviya, Manoj', 'Miller, Colin', 'Manogharan, Guha']
2021-11-16T15:49:07Z
2021-11-16T15:49:07Z
2019
Mechanical Engineering
null
['https://hdl.handle.net/2152/90320', 'http://dx.doi.org/10.26153/tsw/17241']
eng
2019 International Solid Freeform Fabrication Symposium
Open
['design for AM', 'topology optimization', 'design framework', 'eye-tracking', 'manufacturability and additive manufacturing education']
An Empirical Study Linking Additive Manufacturing Design Process to Success in Manufacturability
Conference paper
https://repositories.lib.utexas.edu//bitstreams/5b93b0a5-7270-4ac1-ba9a-d29baf612182/download
University of Texas at Austin
This paper characterizes engineering designers’ abilities to re-design a component for additive manufacturing, employing screen capture methods. Additive Manufacturing has garnered significant interest from a wide range of industries, academia and government stakeholders due to its potential to reform and disrupt traditional manufacturing processes. The technology offers unprecedented design freedom and customization along with its ability to process novel and high strength alloys in promising lead times. To harness the maximum potential of this technology, designers are often tasked with creating new products or re-design existing portfolios of traditionally manufactured parts to achieve lightweight designs with better performance. To date, few studies explore the correspondence between design behaviors and manufacturability of final product within an Additive Manufacturing context. This paper presents empirical data from the design processes of six graduate student engineering designers as they re-design a traditionally designed part for additive manufacturing. Behaviors through the design task are compared between the study participants with a quantitative measure of the manufacturability and quality of each design. Results indicate opportunities for further research and best practices in design for Additive manufacturing and engineering education practitioners across multiple disciplines.
null
null
null
null
null
null
['Bartsch, K.', 'Emmelmann, C.']
2021-12-01T22:07:06Z
2021-12-01T22:07:06Z
2021
Mechanical Engineering
null
['https://hdl.handle.net/2152/90632', 'http://dx.doi.org/10.26153/tsw/17551']
eng
2021 International Solid Freeform Fabrication Symposium
Open
['support structures', 'optimization', 'laser powder bed fusion', 'PBF-LB/M']
Enabling Cost-based Support Structure Optimization in Laser Powder Bed Fusion of Metals
Conference paper
https://repositories.lib.utexas.edu//bitstreams/97680dc1-59fd-406c-a1ff-b084729988a1/download
University of Texas at Austin
Support structures are essential to laser powder bed fusion (PBF-LB/M). They sustain overhangs, prevent distortion, and dissipate process-induced heat. Their removal after manufacturing is required, though, increasing the overall costs. Therefore, optimization is important to increase the economic efficiency of PBF-LB/M. To enable optimization focused on the support structures’ costs, a cost model is developed. The whole production process, including the design, manufacturing, and post-processing of a part is considered by deriving formulas for the individual costs. The cost model is applied to a benchmark procedure previously developed. Additionally, a case study investigating different support layout strategies is conducted.
null
null
null
null
null
null
Clemon, Lee M.
2021-10-28T22:42:11Z
2021-10-28T22:42:11Z
2016
Mechanical Engineering
null
https://hdl.handle.net/2152/89721
eng
2016 International Solid Freeform Fabrication Symposium
Open
['energy consumption', 'global warming emissions', 'fused deposition modeling', 'job-shop']
Energy and Emission Estimation Uncertainty in Fused Deposition Modeling for a Job-Shop
Conference paper
https://repositories.lib.utexas.edu//bitstreams/9e964f38-fcd5-413c-bdb0-0ec6e888458b/download
University of Texas at Austin
Solid freeform fabrication has the potential to affect both financial and environmental concerns for manufacturing enterprises. However, when planning for installation of a new machine tool, accurate energy usage estimation relies heavily on the data and model selections of the estimator. This project used a variety data sources and model decision options to examine the spread of energy consumption and global warming potential estimates for a fused deposition modeling machine. In addition to primary and secondary data sources, the use of similar machines was explored as proxy estimates for the target machine. A Monte Carlo simulation was constructed to vary the model selections, machine utilization, and data sources. The results indicated data sources and model decisions had large effects on the output and that most model estimates were low.
null
null
null
null
null
null
['Kellens, K.', 'Yasa, E.', 'Renaldi', 'Dewulf, W.', 'Kruth, J.P.', 'Duflou, J.R.']
2021-10-04T20:10:24Z
2021-10-04T20:10:24Z
8/17/11
Mechanical Engineering
null
['https://hdl.handle.net/2152/88333', 'http://dx.doi.org/10.26153/tsw/15272']
eng
2011 International Solid Freeform Fabrication Symposium
Open
['Selective Laser Sintering (SLS)', 'Selective Laser Melting (SLM)', 'life cycle assessment', 'sustainable manufacturing', 'energy and resource efficiency', 'CO2PE!-Initiative']
Energy and Resource Efficiency of SLS/SLM Processes
Conference paper
https://repositories.lib.utexas.edu//bitstreams/b180a7c3-5327-4a3a-8e05-bd14c1e80e80/download
University of Texas at Austin
Manufacturing processes, as used for discrete part manufacturing, are responsible for a substantial part of the environmental impact of products, but are still poorly documented in terms of their environmental footprint. The lack of thorough analysis of manufacturing processes has as consequence that optimization opportunities are often not recognized and that improved machine tool design in terms of ecological footprint has only been targeted for a few common processes. Additive manufacturing processes such as Selective Laser Sintering (SLS) and Selective Laser Melting (SLM) allow near-net shape manufacturing of complex work pieces. Consequently, they inherently offer opportunities for minimum-waste and sustainable manufacturing. Nevertheless, powder production, energy consumption as well as powder losses are important and not always optimized environmental impact drivers of SLS and SLM. This paper presents the results of a data collection effort, allowing to assess the overall environmental impact of these processes using the methodology of the CO2PE! (Cooperative Effort on Process Emissions in Manufacturing) initiative. Based on the collected LCI data, a subsequent impact assessment analysis allows identifying the most important contributors to the environmental impact of SLS/SLM. Next to the electricity consumption, the consumption of inert gasses proves to be an important cause of environmental impact. Finally, the paper sketches the improvement potential for SLS/SLM on machine tool as well as system level.
null
null
null
null
null
null
['Patil, Nachiket', 'Pal, Deepankar', 'Stucker, Brent E.']
2021-10-11T22:03:42Z
2021-10-11T22:03:42Z
2013
Mechanical Engineering
null
['https://hdl.handle.net/2152/88659', 'http://dx.doi.org/10.26153/tsw/15593']
eng
2013 International Solid Freeform Fabrication Symposium
Open
['finite element based constitutive model', 'energy dissipation', 'Ultrasonic Consolidation', 'dislocation density based crystal plasticity finite element model', 'weld defects']
An Energy Dissipative Constitutive Model for Multi-Surface Interfaces at Weld Defect Sites in Ultrasonic Consolidation
Conference paper
https://repositories.lib.utexas.edu//bitstreams/540cac9b-3b9f-4b68-8f8c-c1b399b6d2bd/download
University of Texas at Austin
A new finite element based constitutive model has been developed for quantification of energy dissipation due to friction and plastic deformation at the mating interface of two surfaces during the Ultrasonic Consolidation process. This work will include bridging the mesoscopic response of a dislocation density based crystal plasticity finite element framework at inter and intra-granular scales and a point at the macroscopic scale. This response will be used to develop an energy dissipative constitutive model for multi-surface interfaces at the macroscopic scale. The constitutive model will be used for quantification of energy consumed at lack of fusion and trapped oxide defects present in the build and the amount of energy input required to compensate for it. This numerical procedure will help in real time optimization of process parameters and closed loop control.
null
null
null
null
null
null
['Verma, Anoop', 'Rai, Rahul']
2021-10-07T17:46:08Z
2021-10-07T17:46:08Z
2013
Mechanical Engineering
null
['https://hdl.handle.net/2152/88493', 'http://dx.doi.org/10.26153/tsw/15427']
eng
2013 International Solid Freeform Fabrication Symposium
Open
['additive manufacturing', 'optimization', 'energy efficiency', 'material wastage', 'energy consumption', 'medical', 'aerospace']
Energy Efficient Modeling and Optimization of Additive Manufacturing Process
Conference paper
https://repositories.lib.utexas.edu//bitstreams/201111f6-181f-4f4d-97cf-3341e664359b/download
University of Texas at Austin
Additive manufacturing (AM) is a leading technology in various industries including medical and aerospace for prototype and functional part fabrication. Despite being environmentally conscious, avenues pertaining to further reducing the impact of AM on the environment exist. Material wastage and energy consumption are two major concerns of the process that requires immediate attention. In this research, a multi-step optimization enabling additive manufacturing process towards energy efficiency is developed. Process objectives such as material waste and energy consumption are minimized both in part and layer domain. Numerous examples are presented to demonstrate the applicability of the developed approach. The models formulated here for selective laser sintering (SLS) process can be easily extended to other additive manufacturing technologies.
null
null
null
null
null
null
['Sharma, Maharshi A.', 'Patterson, Albert E.']
2024-03-26T17:03:01Z
2024-03-26T17:03:01Z
2023
Mechanical Engineering
null
['https://hdl.handle.net/2152/124375', 'https://doi.org/10.26153/tsw/50983']
en_US
2023 International Solid Freeform Fabrication Symposium
Open
['FFF process', 'extrusion-based additive manufacturing', 'bond-graph model', 'dynamic modeling']
Energy Flow (Bond Graph) Dynamic Modeling of Cartesian-Frame FFF 3-D Printer Gantry
Conference paper
https://repositories.lib.utexas.edu//bitstreams/e87c345f-1cc7-4575-a706-7580e330f929/download
University of Texas at Austin
Energy flow (bond graph) modelling gives important information about the flow of energy to each component of a dynamic system and is especially useful for complex non-linear mechanical systems. This work presents a systematic development of a bond graph model of fused filament fabrication (FFF) 3D printer gantry. The model incorporates structural and belt stiffness, damping and input torque. The model was checked for correctness and causality using the 20-SIM software. The model was further validated using MATLAB-Simulink using parameters obtained for an example printer characterized in a lab environment. The bond graph model gives a unique view into modelling of the extruder carriage dynamics in FFF and can be applied to specific problems. It will also give interesting information on the controllability and system integration of the printer hardware.
null
null
null
null
null
null
['Baumers, M.', 'Tuck, C.', 'Wildman, R.', 'Ashcroft, I.', 'Hague, R.']
2021-10-04T20:18:12Z
2021-10-04T20:18:12Z
8/17/11
Mechanical Engineering
null
['https://hdl.handle.net/2152/88336', 'http://dx.doi.org/10.26153/tsw/15275']
eng
2011 International Solid Freeform Fabrication Symposium
Open
['additive manufacturing', 'electricity consumption', 'AM technology', 'AM technology variants', 'capacity utilization']
Energy Inputs to Additive Manufacturing: Does Capacity Utilization Matter?
Conference paper
https://repositories.lib.utexas.edu//bitstreams/39d4cf41-e8db-4729-af80-b4b01d64a9e0/download
University of Texas at Austin
The available additive manufacturing (AM) platforms differ in terms of their operating principle, but also with respect to energy input usage. This study presents an overview of electricity consumption across several major AM technology variants, reporting specific energy consumption during the production of dedicated test parts (ranging from 61 to 4849 MJ per kg deposited). Applying a consistent methodology, energy consumption during single part builds is compared to the energy requirements of full build experiments with multiple parts (up to 240 units). It is shown empirically that the effect of capacity utilization on energy efficiency varies strongly across different platforms.
null
null
null
null
null
null
['Papadatos, Alexandre L', 'Stanley Jr, Kenneth', 'Ahzi, Said', 'W. Paul, Frank']
2019-02-19T16:45:40Z
2019-02-19T16:45:40Z
1998
Mechanical Engineering
null
['https://hdl.handle.net/2152/73428', 'http://dx.doi.org/10.26153/tsw/580']
eng
1998 International Solid Freeform Fabrication Symposium
Open
['commercial Rapid Prototyping', 'GSI scanners']
Enhanced controlling of the SLS Process during a build
Conference paper
https://repositories.lib.utexas.edu//bitstreams/e6debe7a-38e1-48cd-95d1-1591175c28fd/download
null
Current commercial Rapid Prototyping (RP) systems like Stereolithography (3D Systems Corporation) and Selective Laser Sintering (DTM Corporation) use galvanometers from General Scanning Inc. (GSI) for the positioning of the laser beam. The GSI scanners are delivered as a ''black box". Operating Consoles which are usually Personal Computers (PC) have very few feedback from the performance of the GSI scanners. Therefore, the PC spends 9000 or more of its time waiting for the GSI scanners to be over with the building of the current layer before sending the information regarding the next layer. Also, very little process control can be performed during the scanning of a layer using the GSI scanners. This kind of setup prevents any dynamic controlling of the process that could prevent building errors like burning, warping etc. At Clemson University, our team has developed both hardware and software components that allows a dynamic control of the building process. New features like scanning one vector with laser power as a function of position and/or time are now possible. Both hardware and software issues will be presented.
null
null
null
null
null
null
['Pal, D.', 'Patil, N.', 'Teng, C.', 'Zeng, K.', 'Xu, S.', 'Sublette, T.', 'Stucker, B.']
2021-10-18T22:06:03Z
2021-10-18T22:06:03Z
2014
Mechanical Engineering
null
https://hdl.handle.net/2152/89267
eng
2014 International Solid Freeform Fabrication Symposium
Open
['additive manufacturing', 'spatiotemporal multiscaling', 'thermomechanical travelling wave', 'Finite Element simulations']
Enhancing Simulations of Additive Manufacturing Processes Using Spatiotemporal Multiscaling
Conference paper
https://repositories.lib.utexas.edu//bitstreams/afc09039-a75a-410f-a519-fa8cac1383fa/download
University of Texas at Austin
The three integral components which are common to all additive manufacturing machines are energy source(s), material(s) and geometrical representation(s). The interaction of these components lead to coupled multiscale thermomechanical phenomena. The overall response due to dynamic localized boundary conditions leads to travelling thermomechanical waves with their origin at the point/line or plane of energy input and finite boundaries located at the extremities of the build chamber of the machine. At these finite boundaries, three phenomena occur, namely reflection, absorption and transmission of the thermomechanical travelling wave. Based on the boundary conditions, any combinations of the mentioned finite boundary phenomena are activated leading to a finite mismatch between the boundary condition and ordinate of the travelling wave at the finite boundary abscissae. This finite mismatch leads to another thermomechanical travelling wave which travels from the finite boundary towards the location of energy input and the process of generation of thermomechanical waves continues till a standing steady state thermomechanical wave converges at each snapshot in time. An important aspect of these forward and backward moving travelling waves is their spatiotemporal thermomechanical curvature as a function of space which leads to spatiotemporal multiscale modeling of these processes. Spatial and temporal examples with multi-order and multi-rank updates of thermal eigensolutions with inhomogeneity in the –z direction and thermal stiffness as a function of time stepping were thus studied to understand their effects on efficient Finite Element simulations of metal additive manufacturing processes.
null
null
null
null
null
null
['Jacksch, A.', 'Cholewa, C.', 'Drummer, D.']
2024-03-25T22:10:34Z
2024-03-25T22:10:34Z
2023
Mechanical Engineering
null
['https://hdl.handle.net/2152/124314', 'https://doi.org/10.26153/tsw/50922']
en_US
2023 International Solid Freeform Fabrication Symposium
Open
['polyamide 6', 'PA6', 'thermal stability', 'powder bed fusion', 'PBF', 'additive manufacturing']
Enhancing the Thermal Stability of Polyamide 6 in Powder Bed Fusion via Primary and Secondary Antioxidant Incorporation
Conference paper
https://repositories.lib.utexas.edu//bitstreams/d6726d91-8555-4c1c-9006-de3e848bad2d/download
University of Texas at Austin
Polyamide 6 (PA6) is a thermoplastic material widely used in manufacturing for its excellent mechanical properties, such as high strength, stiffness, and toughness. However, its suitability for powder bed fusion (PBF) is limited due to its susceptibility to thermo-oxidative aging, resulting in material degradation and mechanical property deterioration over time. To address this issue, the efficacy of antioxidants in increasing the aging resistance of PA6 in PBF was investigated. Process-adapted analysis was employed using a coupled rheometer FTIR instrument to elucidate physical and chemical changes in the material. In addition, the viscosity number of the virgin and processed powder, the yellow index, and the part performance were evaluated. Results revealed that the addition of primary and secondary antioxidants significantly enhanced the aging resistance of PA6 in PBF, thereby increasing its potential as a suitable material for additive manufacturing applications.
null
null
null
null
null
null
['Pegues, Jonathan', 'Roach, Michael', 'Williamson, R. Scott', 'Shamsaei, Nima']
2021-11-18T00:01:23Z
2021-11-18T00:01:23Z
2019
Mechanical Engineering
null
['https://hdl.handle.net/2152/90363', 'http://dx.doi.org/10.26153/tsw/17284']
eng
2019 International Solid Freeform Fabrication Symposium
Open
['stress corrosion cracking', 'environmentally assisted cracking', 'austenitic stainless steel', 'tensile properties']
Environmental Effects on the Stress Corrosion Cracking Behavior of an Additively Manufactured Stainless Steel
Conference paper
https://repositories.lib.utexas.edu//bitstreams/f1cd0a9b-b22c-4440-9c0c-5d12cba7a0d1/download
University of Texas at Austin
Additive manufacturing (AM) is becoming a more viable manufacturing process in the biomedical, aerospace, nuclear, and defense sectors as a means to fabricate near net shaped parts on demand. Austenitic stainless steels are gaining attention for AM of products for these applications due to their ease of fabrication, excellent corrosion resistance, and superior toughness. The performance of these alloys fabricated by AM techniques such as laser beam powder bed fusion has not been yet fully established. This research compares the microstructural characteristics and tensile stress corrosion cracking (SCC) of 316L stainless steel at room temperature and physiological temperature in distilled H2O, salt water, Ringers, and spiked pH Ringers conditions.
null
null
null
null
null
null
['Niu, Michelle', 'Nauka, Krztsztof']
2024-03-27T03:11:44Z
2024-03-27T03:11:44Z
2023
Mechanical Engineering
null
['https://hdl.handle.net/2152/124458', 'https://doi.org/10.26153/tsw/51066']
en_US
2023 International Solid Freeform Fabrication Symposium
Open
['metal powder surface energy modification', 'additive manufacturing', 'high energy light irradiation']
Equalization of Metal Powder for Binder Jet Printing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/c7a7d8b3-f874-4cd5-a3c4-aff534f51f0b/download
University of Texas at Austin
Metal powders used in additive manufacturing often face the issue of variable powder surface characteristics, causing inconsistent part quality. As such, a ”homogenization” treatment for metal powder surfaces may be advantageous for relevant fabrication processes. By using high-powered xenon flash lamp to rapidly heat powder samples, the surface energy of the powder particles was brought to the same value regardless of the powder source and past usage. Pulse-heating the powder caused the atomic structure of particle surfaces to undergo rearrangement and removed adsorbed moieties. Effects of this treatment on metal powders have been investigated and evaluated by measuring the time before water droplets are absorbed on treated and untreated thin layers.
null
null
null
null
null
null
['Miyanaji, Hadi', 'Yang, Li']
2021-11-01T20:44:47Z
2021-11-01T20:44:47Z
2016
Mechanical Engineering
null
https://hdl.handle.net/2152/89742
eng
2016 International Solid Freeform Fabrication Symposium
Open
['binder jetting', '3D printing', 'equilibrium saturation', 'spreading', 'penetration']
Equilibrium Saturation in Binder Jetting Additive Manufacturing Processes: Theoretical Model vs Experimental Observations
Conference paper
https://repositories.lib.utexas.edu//bitstreams/754e405e-c88f-4d88-8d1b-502a5f5ead0f/download
University of Texas at Austin
In Binder Jetting 3D Printing process, a feature is fabricated by depositing binder in the selective regions layer by layer until the geometry is completed. One of the main factors which influences the accuracy and strength of the green parts in this process is the spreading (i.e. lateral migration) and penetration (vertical migration) of the binder in powder bed, which is in turn determined by the capillary equilibrium between the saturated regions and the unsaturated powder. In the present study, a previously developed model for binder migration was applied to 420 stainless steel in order to evaluate the equilibrium saturation levels. Characterizations such as contact angle, specific surface area, succession pressure and capillary pressure were carried out in order to determine the theoretical equilibrium saturation amount. Furthermore, 10 single lines with dimensions of 46μm in diameter and 3mm in length were printed out and analyzed for empirical saturation level. The results of the theoretical model and experimental work were compared and discussed in details to validate its applicability in binder jetting process development.
null
null
null
null
null
null
['Kleszczynski, S.', 'zur Jacobsmühlen, J.', 'Sehrt, J.T.', 'Witt, G.']
2021-10-07T14:46:56Z
2021-10-07T14:46:56Z
8/15/12
Mechanical Engineering
null
['https://hdl.handle.net/2152/88467', 'http://dx.doi.org/10.26153/tsw/15404']
eng
2012 International Solid Freeform Fabrication Symposium
Open
['Laser Beam Melting', 'error detection', 'high-resolution imaging', 'aerospace', 'medicine']
Error Detection in Laser Beam Melting Systems by High Resolution Imaging
Conference paper
https://repositories.lib.utexas.edu//bitstreams/b800d101-afd4-43b4-8362-8a6d96e64e83/download
University of Texas at Austin
Laser Beam Melting as a member of Additive Manufacturing processes allows the fabrication of three-dimensional metallic parts with almost unlimited geometrical complexity and very good mechanical properties. However, its potential in areas of application such as aerospace or medicine has not yet been exploited due to the lack of process stability and quality management. For that reason samples with pre-defined process irregularities are built and the resulting errors are detected using high-resolution imaging. This paper presents an overview of typical process errors and proposes a catalog of measures to reduce process breakdowns. Based on this systematical summary a future contribution to quality assurance and process documentation is aspired.
null
null
null
null
null
null
['Masoomi, Mohammad', 'Paudel, Basil', 'Shamsaei, Nima', 'Thompson, Scott M.']
2021-11-11T16:51:55Z
2021-11-11T16:51:55Z
2018
Mechanical Engineering
null
['https://hdl.handle.net/2152/90247', 'http://dx.doi.org/10.26153/tsw/17168']
eng
2018 International Solid Freeform Fabrication Symposium
Open
['laser-powder bed fusion', 'numerical simulation', 'numerical modeling', 'temperature gradiennt', 'part performance']
Establishing Property-Performance Relationships through Efficient Thermal Simulation of the Laser-Powder Bed Fusion Process
Conference paper
https://repositories.lib.utexas.edu//bitstreams/dfa85c35-97e4-4a71-af40-2ebeb89e85ef/download
University of Texas at Austin
In order to learn how to modify additive manufacturing designs and processes to ensure lab-scale specimens and final components have similar properties, it is important that process-property relationships be established through thermal simulations. In this study, two unique numerical methods for efficiently predicting the thermal history of additively manufactured parts via simulation are presented and validated. These numerical methods make use of an idealized, constant/uniform heat flux which is applied at each new layer and ‘bulk-layers’ which consist of several layers and allow the use of coarser meshes and longer time steps. To demonstrate and test the numerical methods, simulations are ran for the laser-powder bed fusion (L-PBF) of stainless steel (SS) 17-4 PH parts with different volumes. Simulation results indicate how to modify L-PBF process parameters, specifically time intervals, to better ensure a similar thermal history, temperature, temperature gradient and cooling rate, of different sized/shaped parts.
null
null
null
null
null
null
['Johnson, A.', 'Bingham, G.A.', 'Majewski, C.E.']
2021-10-05T19:10:02Z
2021-10-05T19:10:02Z
8/22/12
Mechanical Engineering
null
['https://hdl.handle.net/2152/88412', 'http://dx.doi.org/10.26153/tsw/15351']
eng
2012 International Solid Freeform Fabrication Symposium
Open
['Additive Manufactured Body Armour', 'Laser Sintering', 'body armour', 'Home Office Scientific Development Branch', 'National Institute of Justice']
Establishing the Performance Requirements for Stab Resistant Additive Manufactured Body Armour (AMBA)
Conference paper
https://repositories.lib.utexas.edu//bitstreams/c29d7ade-4d2f-4142-a615-9663ddc31896/download
University of Texas at Austin
Body armour is worn to lessen the likelihood of sustaining a life threatening injury. Such protective solutions are used every day by law enforcement officers around the world, with strict guidelines governing their design and testing. These activities are monitored by government departments such as the Home Office Scientific Development Branch (HOSDB) within the United Kingdom (UK), and the National Institute of Justice (NIJ) within the United States. Despite providing protection against significant levels of impact energy, a number of historical issues continue to be present with modern fibre-based soft body armour – which once addressed may demonstrate an enhancement wearer operational performance. This paper therefore presents research highlighting such issues, and demonstrates how Additive Manufacturing (AM) technologies, particularly Laser Sintering (LS), could potentially be used to address such operational concerns whilst providing protection against a real-world threat. Results documented within this paper demonstrate that 5.6 mm thick planar samples, Laser Sintered from a 50/50 mix of virgin and recycled PA 2200 successfully achieved penetration resistance to the UK HOSDB KR1 impact energy of 24 joules. These results therefore influenced the design, manufacture, and testing of a series of AM textile samples featuring an imbricated layout, which also demonstrated successful knife penetration resistance to the HOSDB KR1 level – thus developing stab resistant Additive Manufactured Body Armour (AMBA).
null
null
null
null
null
null
['Park, Sang-in', 'Watanabe, Narumi', 'Rosen, David W.']
2021-11-04T19:26:10Z
2021-11-04T19:26:10Z
2017
Mechanical Engineering
null
['https://hdl.handle.net/2152/90009', 'http://dx.doi.org/10.26153/16930']
eng
2017 International Solid Freeform Fabrication Symposium
Open
['material extrusion', 'lattice structure', 'b', 'bonding strength', 'strength', 'deposition modeling', 'fracture mechanics']
Estimating Strength of Lattice Structure Using Material Extrusion Based on Deposition Modeling and Fracture Mechanics
Conference paper
https://repositories.lib.utexas.edu//bitstreams/6260c31e-a422-457e-bb6c-e34224f8bd56/download
University of Texas at Austin
Geometrical complexity in lattice structures yields large bounding surfaces to be approximated during additive manufacturing (AM) processes. In material extrusion, approximation of geometries using finite-sized thin filaments introduces defects such as voids and gaps in as-fabricated geometries. This initiates cracks between layers and increases possibility of fracture by crack propagation. As a result, a lattice structure fabricated by material extrusion tends to fail at significantly lower stress than estimated strength without consideration of fracture mechanism. The goal of this research is to estimate strength of material extruded lattice structures considering bonding strength among layers. To achieve this, the bonding strength is determined based on a deposition process modeling scheme and fracture mechanics analysis. A two-layer deposition model is generated to investigate deposited geometry, and the effective interlayer-bonding strength is calculated using a cohesive zone model (CZM) and peel tests. The resulting strength is incorporated into the property-estimation procedure.
null
null
null
null
null
null
['Marshall, Garrett J.', 'Thompson, Scott M.', 'Daniewicz, Steve R.', 'Shamsaei, Nima']
2021-10-26T19:10:36Z
2021-10-26T19:10:36Z
2016
Mechanical Engineering
null
https://hdl.handle.net/2152/89560
eng
2016 International Solid Freeform Fabrication Symposium
Open
['directed energy deposition', 'part size', 'thermal resistance', 'thermal resistance network']
Estimating the Effects of Part Size on Direct Laser Deposition Parameter Selection via a Thermal Resistance Network Approach
Conference paper
https://repositories.lib.utexas.edu//bitstreams/1dbd50a2-e53f-48b3-a3cc-30670758b4d9/download
University of Texas at Austin
A mathematical model for heat transfer during the Directed Energy Deposition (DED) process is proposed. The model employs the thermal resistance network analogy and is developed to aid one in predicting part size effects on its temperature distribution during manufacture, and in how to compensate such effects via suitable process parameter selection. The model predicts a pseudo steady-state temperature response in the melt pool. The temperature variation along the heat affected zone of a thin-walled part is estimated while assuming deposition is occurring far from the substrate. Predicted melt pool and bulk part temperatures are validated against Laser Engineering Net Shaping (LENSTM) experimental data obtained via a dual-wavelength pyrometer and in-chamber infrared camera, respectively. Results demonstrate that the model may be used to predict an average melt pool temperature. Bulk, calculated temperature distribution needs to be further investigated to find a more suitable heat transfer coefficient surrounding the part.
null
null
null
null
null
null
['Reichwein, J.', 'Geis, J.', 'Kirchner, E.']
2023-04-03T17:21:43Z
2023-04-03T17:21:43Z
2022
Mechanical Engineering
null
['https://hdl.handle.net/2152/117722', 'http://dx.doi.org/10.26153/tsw/44601']
eng
2022 International Solid Freeform Fabrication Symposium
Open
Laser powder bed fusion
Evaluating Concepts for the Integration of Milled Components into the Additive Manufacturing Process
Conference paper
https://repositories.lib.utexas.edu//bitstreams/3b155ea5-f148-4594-a5c3-a8ab9a78f02d/download
null
Laser Powder Bed Fusion (L-PBF) has specific advantages over conventional manufacturing processes. These include high freedom in the design of components and cost- efficient production of small quantities. However, the surface quality of components is low compared to milling and the production of large components is often associated with high costs. These challenges are addressed by integrating milled components into the L-PBF process. Therefore, various concepts are presented for positioning, aligning, and fastening machined components in the build space of the L-PBF system with the goal to provide a reliable way to start the L-PBF process on top of these components. Thus, allowing the potential of additive and subtractive manufacturing to be exploited without requiring an additional joining operation. Finally, these concepts are applied to a steering shaft bracket and the costs for manufacturing are evaluated. A 25% reduction in manufacturing costs was achieved compared to the purely additively manufactured component.
null
null
null
null
null
null
['Hasbrouck, C.R.', 'Melnik, Samantha A.']
2024-03-27T03:57:39Z
2024-03-27T03:57:39Z
2023
Mechanical Engineering
null
['https://hdl.handle.net/2152/124479', 'https://doi.org/10.26153/tsw/51087']
en_US
2023 International Solid Freeform Fabrication Symposium
Open
['additive manufacturing', 'material extrusion', 'metalcasting', 'compressive strength', 'risers', 'patterns', 'hybrid manufacturing', 'desktop printers']
EVALUATING THE COMPRESSIVE STRENGTH OF AM RISERS FOR GREEN SAND METALCASTING
Conference paper
https://repositories.lib.utexas.edu//bitstreams/88ebe5be-677c-4091-b042-3d27a8878c49/download
University of Texas at Austin
While many metalcasting foundries have experimented with using additive manufacturing (AM) for patternmaking, the compressive strength of the tapered AM risers for green sand metalcasting has not yet been explored. This study investigates the effects of infill pattern type, infill density, and shell thickness on the compressive strength of a standard 3-inch diameter by 5-inch tall by 3-degree taper cylindrical riser manufactured with PLA using a material extrusion process. The findings for these AM risers include plots and mathematical models of compressive strengths at three different scales of the standard geometry (full, three-quarters, and half), predicted build times and masses using other common infill patterns, potential failure mechanisms during use of AM and conventionally manufactured riser patterns, and considerations on design for both additive manufacturing and green sand metalcasting. It is concluded that AM risers can be incorporated into and perform well as part of conventional green sand metalcasting patterns.
null
null
null
null
null
null
['Grech, I.S.', 'Wint, N.', 'Mehraban, S.', 'Sullivan, J.', 'Lavery, N.']
2021-11-18T00:20:31Z
2021-11-18T00:20:31Z
2019
Mechanical Engineering
null
['https://hdl.handle.net/2152/90367', 'http://dx.doi.org/10.26153/tsw/17288']
eng
2019 International Solid Freeform Fabrication Symposium
Open
['corrosion performance', 'Invar', '17-4PH', 'wrought', 'additive manufacturing', 'laser powder bed fusion', 'LPBF', 'Renishaw AM 400']
Evaluating the Corrosion Performance of Wrought and Additively Manufactured (AM) Invar ® and 17-4PH
Conference paper
https://repositories.lib.utexas.edu//bitstreams/f68fb304-df3b-4526-9b32-5f0a1c6894ae/download
University of Texas at Austin
A Renishaw AM 400 was used to produce Laser Powder Bed fusion (LPBF) iron alloy Invar ® and 17-4PH components. Build parameters were systematically changed and the corrosion performance of the samples produced was investigated using a combination of scanning vibrating electrode technique (SVET) and advanced conventional electrochemical techniques. The results indicated that small changes in the density of the LPBF parts due to porosity resulted in large changes to the materials corrosion susceptibility. The LPBF samples also demonstrated significantly more variation in pitting potential measurements compared to wrought samples indicating inhomogeneity in the built parts. References to AM samples in this work refer to samples produced using LPBF.
null
null
null
null
null
null
['Bales, Brenin', 'Smith, Tyler', 'Kim, Seokpum', 'Kunc, Vlastimil', 'Duty, Chad']
2021-12-01T23:21:45Z
2021-12-01T23:21:45Z
2021
Mechanical Engineering
null
['https://hdl.handle.net/2152/90653', 'http://dx.doi.org/10.26153/tsw/17572']
eng
2021 International Solid Freeform Fabrication Symposium
Open
['z-pinning', 'CF-PLA', 'mechanical strength', 'toughness', 'fused filament fabrication']
Evaluating the Effect of Z-pinning Parameters on the Mechanical Strength and Toughness of Printed Polymer Composite Structures
Conference paper
https://repositories.lib.utexas.edu//bitstreams/43fac7ab-f19d-4138-ba57-09a4f53e1a9c/download
University of Texas at Austin
Traditional Fused Filament Fabrication methods create a mechanically anisotropic structure that is stronger in the deposition plane than across successive layers. A recently developed pinning process deposits continuous pins in the structure that are orientated in the build direction across multiple layers. Initial studies of this technique have demonstrated the ability to increase inter-layer strength and toughness. The current study evaluated various z-pinning parameters for carbon fiber reinforced polylactic acid (CF-PLA) structures, including infill percentage, pin length, and deposition pattern. Each of these was found to affect the ability of the z-pin to mechanically bond with the existing lattice structure and had a resulting impact on the mechanical strength and toughness. Initial studies showed an increase in ultimate tensile strength in the Z-axis of around 3.5x. Upon expanding the pinning settings, further studies showed increases of over 35% from the X and Z axis ultimate tensile strength and improved mechanically isotropic behavior.
null
null
null
null
null
null
['Brackett, J.', 'Defilippis, A.', 'Smith, T.', 'Hassen, A.', 'Kunc, V.', 'Duty, C.']
2023-04-03T15:40:04Z
2023-04-03T15:40:04Z
2022
Mechanical Engineering
null
['https://hdl.handle.net/2152/117718', 'http://dx.doi.org/10.26153/tsw/44597']
eng
2022 International Solid Freeform Fabrication Symposium
Open
Additive manufacturing
Evaluating the Mechanical Properties within the Transition Region of Multi-Material Large-Format Extrusion Additive Manufacturing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/54ac5031-d934-4e5f-ab0c-c7efda58b315/download
null
Recent developments in Large-Format Additive Manufacturing (LFAM) have enabled in- situ material changes and production of graded Multi-Material (MM) structures. The Big Area Additive Manufacturing (BAAM) system utilizes a dual-hopper configuration to feed different materials into a screw-based extruder which results in a blended material transition rather than a discrete material boundary, avoiding associated delamination issues. While this system enables site-specific material deposition at a large scale, the mechanical performance within the transition region needs to be evaluated to determine the impact on end-part performance. Additionally, the transition region can exhibit incomplete mixing, which could further influence mechanical performance. This study investigates the change in mechanical properties throughout the transition region using dynamic mechanical analysis and tensile testing of printed samples. Optical microscopy of the internal microstructure of the printed beads was also utilized to determine the influence of material blending within the transition on mechanical performance.
null
null
null
null
null
null
['Rodomsky, Caitlyn', 'Conner, Brett']
2021-11-09T14:35:49Z
2021-11-09T14:35:49Z
2018
Mechanical Engineering
null
['https://hdl.handle.net/2152/90081', 'http://dx.doi.org/10.26153/tsw/17002']
eng
2018 International Solid Freeform Fabrication Symposium
Open
['surface roughness', 'stair step features', 'binder jetting', 'sand printing', 'metal castings']
Evaluating the Surface Finish of A356-T6 Cast Parts from Additively Manufactured Sand Molds
Conference paper
https://repositories.lib.utexas.edu//bitstreams/833aad61-f854-4ab9-a5ac-1ef6cb4b99ed/download
University of Texas at Austin
Binder jetting of sand allows for the design and rapid fabrication of complex molds and cores. The surface finish of the printed molds and cores can be transferred to the cast part. A benchmark casting was designed to compare the surface roughness and surface features of several angles on the cast part. The benchmark casting contained surfaces with angles from 5° to 30° at 5° intervals. Benchmark castings from coated and uncoated mold surfaces were evaluated. Angles from 5° to 20° produced a prominent stair step feature. A Keyence microscope was used to measure the arithmetic mean roughness (Ra) and root mean square surface roughness (Rq) of the part surfaces. These measurements are compared to a more conventional contact profilometer. The suitability of Ra and Rq for characterizing stair step features will be discussed.
null
null
null
null
null
null
['Roberson, David A.', 'Rocha, Carmen R.', 'Piñon, Monica']
2021-10-21T15:07:50Z
2021-10-21T15:07:50Z
2015
Mechanical Engineering
null
https://hdl.handle.net/2152/89389
eng
2015 International Solid Freeform Fabrication Symposium
Open
['3D printing', 'materials characterization', 'polymer matrix composites']
Evaluation of 3D Printable Sustainable Composites
Conference paper
https://repositories.lib.utexas.edu//bitstreams/32d14c1d-5192-46d9-8b83-c2745e772f63/download
University of Texas at Austin
Polylactic acid (PLA) is rapidly becoming the mainstay material for use in desktop grade 3D printers based on FDM technology in part due to the environmental sustainability of this polymer. While biodegradability is an advantage; as compared to other materials used by FDM-type platforms, there is a lack of desirable physical attributes. The work presented here evaluates the altering of the physical properties of PLA through the addition of sustainable additives. Here, the physical properties of PLA were modified while, at the same time the two desirable aspects of 3D printer compatibility and biodegradability were retained. Rheological analysis of the material systems was performed by dynamic mechanical analysis and failure analysis of 3D printed tensile specimens was carried out through the use of scanning electron microscopy. Finally, biodegradability of the novel PLA-based material systems was assessed based on in-soil exposure testing.
null
null
null
null
null
null
['Carrion, Patricio E.', 'Graves, Lynne M.', 'Yampolskiy, Mark', 'Shamsaei, Nima']
2021-12-01T22:09:20Z
2021-12-01T22:09:20Z
2021
Mechanical Engineering
null
['https://hdl.handle.net/2152/90633', 'http://dx.doi.org/10.26153/tsw/17552']
eng
2021 International Solid Freeform Fabrication Symposium
Open
['additive manufacturing', 'laser powder bed fusion', 'AM security', 'cyber-physical attack', 'sabotage']
Evaluation of a Cyber-Physical Attack Effectiveness in Metal Additive Manufacturing by Selectively Modifying Build Layer Thickness
Conference paper
https://repositories.lib.utexas.edu//bitstreams/0ae86437-ba24-4993-8c9c-d0e764e1c37c/download
University of Texas at Austin
To produce functional parts satisfying required functional characteristics, Additive Manufacturing (AM) process maintains a combination of numerous parameters within material-dependent ranges; these include power density, scanning speed, hatch distance, and layer thickness. Unintentional misconfiguration of these parameters is easily detectable as it impacts the entire build. In this paper, however, we consider the case of a deliberate sabotage attack which causes misconfiguration localized to only few strategically selected layers. We propose a method on how such targeted misconfigurations can be executed without hacking into the firmware. Specifically, we altered a build file to mimic localized layer thickness modification by disabling laser beam exposure, while maintaining geometrical and visual part integrity. For two distinct laser powder bed fusion (L-PBF) systems and two metal alloys, we validated empirically the impact of such attack on part quality and demonstrated that it can avoid detection by non-destructive techniques (NDT). The conducted attack illustrates susceptibility of AM to deliberate sabotage attacks and motivates the need of security solutions for this increasingly adopted manufacturing technology.
null
null
null
null
null
null
['Paterson, A.M.', 'Bibb, R.J.', 'Campbell, R.I.']
2021-10-06T21:06:27Z
2021-10-06T21:06:27Z
8/16/12
Mechanical Engineering
null
['https://hdl.handle.net/2152/88443', 'http://dx.doi.org/10.26153/tsw/15380']
eng
2012 International Solid Freeform Fabrication Symposium
Open
['wrist splints', 'additive manufacturing', 'multiple-material', 'Objet Connex']
Evaluation of a Digitsed Splinting Approach with Multiple-Material Functionality Using Additive Manufacturing Technologies
Conference paper
https://repositories.lib.utexas.edu//bitstreams/e3538934-d3a2-4111-b545-eca03871f31b/download
University of Texas at Austin
The design and fabrication of custom-made wrist immobilisation splints can be a laborious process. In addition, patient adherence in terms of wear duration and frequency may be affected by a range of contributing factors including poor aesthetics, hygiene issues and fit. This paper suggests the use of additive manufacturing (AM) in a bid to resolve factors affecting adherence and improve the efficiency of design and manufacture. Particular attention is paid to the exploitation of multiple-material capabilities using Objet Connex technologies, with the intent to integrate completely novel and state-of-the-art characteristics within splints. However, in order to exploit the many benefits of AM for customised splint fabrication, appropriate Three Dimensional (3D) Computer Aided Design (CAD) methodologies must be considered for splint design. Furthermore, a specialised CAD approach must be developed for splinting practitioners to allow them to create such geometries. As a result, this paper describes the development of a customised 3D CAD methodology for splinting practitioners to design custom-made splints, in order to evaluate such novel features only available through AM fabrication.
null
null
null
null
null
null
['Phillips, T.', 'Fish, S.', 'Beaman, J.']
2021-11-18T19:02:28Z
2021-11-18T19:02:28Z
2019
Mechanical Engineering
null
['https://hdl.handle.net/2152/90469', 'http://dx.doi.org/10.26153/tsw/17390']
eng
2019 International Solid Freeform Fabrication Symposium
Open
['feed-forward laser control', 'thermal control', 'in-situ', 'consistency', 'selective laser sintering']
Evaluation of a Feed-Forward Laser Control Approach for Improving Consistency in Selective Laser Sintering
Conference paper
https://repositories.lib.utexas.edu//bitstreams/b895af86-55ed-4269-9281-abcac4908063/download
University of Texas at Austin
Selective Laser Sintering (SLS) is a popular industrial additive manufacturing technique for creating functional polymer components. One of the biggest limitations today with SLS is its poor mechanical consistency when compared with traditional manufacturing techniques, inhibiting the use of SLS among structurally critical components. Evaluation of the SLS process has revealed that the quality of components is strongly affected by the thermal history during the build process and poor control over this can lead to premature part failure. This paper will discuss a novel technique of improving in-situ thermal control by implementing a feed-forward laser controller that uses dynamic surrogate modelling to predict optimal laser power to achieve desired thermal characteristics. Thermal and destructive testing results will be presented showing that the described laser power controller is capable of decreasing the standard deviations of post sintering temperature by up to 57% and ultimate flexural strength by up to 45%.
null
null
null
null
null
null
['Petros, Matthew', 'Torabi, Payman', 'Khoshnevis, Behrokh']
2021-10-12T22:34:37Z
2021-10-12T22:34:37Z
2014
Mechanical Engineering
null
['https://hdl.handle.net/2152/88757', 'http://dx.doi.org/10.26153/tsw/15691']
eng
2014 International Solid Freeform Fabrication Symposium
Open
['Selective Inhibition Sintering', 'SIS-metal', 'metal alloys', 'additive manufacturing', 'layer-processing', 'cross-sectional image generation scheme']
An Evaluation of Cross-Sectional Image Generation Schemes in the Selective Inhibition Sintering (SIS) Process
Conference paper
https://repositories.lib.utexas.edu//bitstreams/b9b02fbc-f17a-47c2-bfe9-cdfe512ab78b/download
University of Texas at Austin
Selective Inhibition Sintering of metal alloys (SIS-metal) has been proven effective in the additive manufacture (AM) of low resolution bronze parts. The use of high precision inkjet print heads represents a significant advancement in the SIS-metal process. The fabrication of complex three-dimensional metallic parts requires SIS-metal compatible, cross-sectional image processing based on the part boundary profile. Thus, three candidate layer-processing approaches were identified and validated for rudimentary geometries. These approaches were identified from previous research as well as preliminary investigations. The validation criteria is based upon maintaining part integrity, the amount of powder waste produced, processing time, the ability to handle various part geometries, and the ease of access to inhibited regions. Results are discussed for deploying the three candidate layer processing approaches for rudimentary shapes, and a preliminary evaluation is presented for their use on more complex geometries.
null
null
null
null
null
null
['Fu, Tian', 'Sparks, Todd E.', 'Liou, Frank', 'Newkirk, Joseph', 'Fan, Zhiqiang', 'Pulugurtha, Syamala R.']
2021-09-29T14:28:04Z
2021-09-29T14:28:04Z
2009-09
Mechanical Engineering
null
['https://hdl.handle.net/2152/88182', 'http://dx.doi.org/10.26153/tsw/15123']
eng
2009 International Solid Freeform Fabrication Symposium
Open
['aircraft landing gears', 'stainless steels', 'laser cladding', 'AISI 4340']
Evaluation of Direct Diode Laser Deposited Stainless Steel 316L on 4340 Steel Substrate for Aircraft Landing Gear Application
Conference paper
https://repositories.lib.utexas.edu//bitstreams/db3bb050-246e-4854-a97c-2b87c27d4967/download
University of Texas at Austin
300M steel is used extensively for aircraft landing gears because of its high strength, ductility and toughness. However, like other high-strength steels, 300M steel is vulnerable to corrosion fatigue and stress corrosion cracking, which can lead to catastrophic consequences in the landing gear. Stainless steels offer a combination of corrosion, wear, and fatigue properties. But for an aircraft landing gear application a higher surface hardness is required. A laser cladding process with fast heating and cooling rates can improve the surface hardness. AISI 4340 steel is used as a lower cost alternative to 300M due to its similar composition. In this study, the influence of laser cladding process parameters, shield gas, and composition of the deposition and dilution zone has been investigated. The microstructures and composition analysis were evaluated by Scanning Electron Microscopy (SEM) and Optical Microscopy. The deposition hardness varies from 330HV to 600HV.
null
null
null
null
null
null
['Dharmadhikari, Susheel', 'Basak, Amrita']
2021-12-06T21:51:30Z
2021-12-06T21:51:30Z
2021
Mechanical Engineering
null
['https://hdl.handle.net/2152/90685', 'http://dx.doi.org/10.26153/tsw/17604']
eng
2021 International Solid Freeform Fabrication Symposium
Open
['fatigue failure detection', 'laser powder bed fusion', 'force-displacement sensors', 'confocal microscope']
Evaluation of Early Fatigue Damage Detection in Additively Manufactured AlSi10Mg
Conference paper
https://repositories.lib.utexas.edu//bitstreams/fcc2295e-a558-4ca0-9990-d3b85e6da19b/download
University of Texas at Austin
The article presents two distinct measures for fatigue damage detection in additively manufactured AlSi10Mg specimens with a one-sided V-notch. The specimens are fabricated on a ProX-320 laser powder bed fusion equipment with recycled AlSi10Mg powders using vetted process parameters as suggested by 3D Systems. The process of fatigue damage evolution is monitored using two heterogeneous sensing techniques, namely, the force-displacement sensors and a confocal microscope. The force and displacement sensors are embedded in the fatigue testing apparatus to capture the global effects of the stress-strain behavior of the specimens; however, it provides no information about the local damage near the notch. The force-displacement time-series data, which shows a hysteresis-like behavior, is calibrated using a confocal microscope focused inside the notch of the specimen so that the onset of fatigue crack initiation can be detected at a crack opening displacement (COD) of ~10 microns. Using the force-displacement data, the energy dissipation rate and the material stiffness per cycle are computed. The results show a detection accuracy of 96.25% and 90.84% for the energy dissipation rate and material stiffness per cycle, respectively. In conclusion, the paper establishes two successful predictors for fatigue damage detection in additively manufactured AlSi10Mg specimens.
null
null
null
null
null
null
['Ravichander, Bharath Bhushan', 'Jagdale, Shweta Hanmant', 'Theeda, Sumanth', 'Kumar, Golden']
2023-03-28T19:27:52Z
2023-03-28T19:27:52Z
2022
Mechanical Engineering
null
['https://hdl.handle.net/2152/117669', 'http://dx.doi.org/10.26153/tsw/44548']
eng
2022 International Solid Freeform Fabrication Symposium
Open
['Laser powder bed fusion', 'Functionally Graded Lattice', 'Porosity', 'SS316L', 'part density']
Evaluation of Functionally Graded Lattice Properties of Laser Powder Bed Fused Stainless Steel 316L
Conference paper
https://repositories.lib.utexas.edu//bitstreams/6d5f7f7c-d855-49c1-a6bb-d259ef6424ce/download
null
The development of metal Additive Manufacturing (AM) techniques, in particular the laser powder bed fusion (LPBF) process, has led to an increase in the innovative design and fabrication of lightweight and complex porous metal structures. Despite the limitations of the LPBF process which limits the geometric accuracy of the porous structures, it eliminates the difficulties presented by conventional manufacturing techniques in the fabrication of highly complex structures. The properties of as-built porous structures depend on the unit cell design and porosity level. These lightweight metal structures have applications in medical and aerospace fields. The relationships between the lattice geometry and performance must be determined to successfully implement the functional lattice designs. In this study, functionally graded lattice structures are fabricated from steel using SLM technique and the effect of different lattice types on the manufacturability, density and mechanical properties are investigated.
null
null
null
null
null
null
['Ravichander, B.B.', 'Jagdale, S.H.', 'Theeda, S.', 'Kumar, G.']
2023-04-05T17:19:34Z
2023-04-05T17:19:34Z
2022
Mechanical Engineering
null
['https://hdl.handle.net/2152/117783', 'http://dx.doi.org/10.26153/tsw/44662']
eng
2022 International Solid Freeform Fabrication Symposium
Open
['Laser powder bed fusion', 'Functionally Graded Lattice', 'Porosity', 'SS316L', 'Part Density']
Evaluation of Functionally Graded Lattice Properties of Laser Powder Bed Fused Stainless Steel 316L
Conference paper
https://repositories.lib.utexas.edu//bitstreams/0600ed02-f778-4ebe-acbe-a442b8182064/download
null
The development of metal Additive Manufacturing (AM) techniques, in particular the laser powder bed fusion (LPBF) process, has led to an increase in the innovative design and fabrication of lightweight and complex porous metal structures. Despite the limitations of the LPBF process which limits the geometric accuracy of the porous structures, it eliminates the difficulties presented by conventional manufacturing techniques in the fabrication of highly complex structures. The properties of as-built porous structures depend on the unit cell design and porosity level. These lightweight metal structures have applications in medical and aerospace fields. The relationships between the lattice geometry and performance must be determined to successfully implement the functional lattice designs. In this study, functionally graded lattice structures are fabricated from steel using SLM technique and the effect of different lattice types on the manufacturability, density and mechanical properties are investigated.
null
null
null
null
null
null
['Davis, T.M.', 'Crane, N.B.']
2021-12-06T22:01:53Z
2021-12-06T22:01:53Z
2021
Mechanical Engineering
null
['https://hdl.handle.net/2152/90689', 'http://dx.doi.org/10.26153/tsw/17608']
eng
2021 International Solid Freeform Fabrication Symposium
Open
['liquid dopants', 'liquid deposition', 'direct write', 'inkjet deposition', 'laser powder bed fusion']
Evaluation of Liquid Doping Methods for Use in Laser Powder Bed Fusion
Conference paper
https://repositories.lib.utexas.edu//bitstreams/aa7ce7f4-9089-465a-b274-f8d288b9c156/download
University of Texas at Austin
Laser powder bed fusion (LPBF) is an additive manufacturing (AM) process that is well known for its geometric versatility and high-quality parts. While the properties of LPBF parts are commonly superior to those made using other AM techniques, LPBF is generally limited to a single material in any given build. While LPBF can accommodate the integration of multiple components into a single part geometrically, the material limitation leads to over-designing to ensure that every component can complete their various functions. Some studies have shown potential methods of 3D composition control throughout a part, but these methods are subject to high cost increases due to build time increases and decreased powder recyclability. A new approach to multi-material LPBF uses liquid dopants to alter the composition in location-specific areas. The current study evaluates two different liquid deposition methods – direct write and inkjet deposition – in relation to their adaptability and utility in LPBF. Inkjet deposition is shown to have significant benefits compared to the direct write method.
null
null
null
null
null
null
['Bao, Yaxin', 'Ruan, Jianzhong', 'Sparks, Todd E.', 'Anand, Jambunathan', 'Newkirk, Joseph', 'Liou, Frank']
2020-02-28T16:27:53Z
2020-02-28T16:27:53Z
9/14/06
Mechanical Engineering
null
['https://hdl.handle.net/2152/80116', 'http://dx.doi.org/10.26153/tsw/7137']
eng
2006 International Solid Freeform Fabrication Symposium
Open
Microstructure
Evaluation of Mechanical Properties and Microstructure for Laser Deposition Process and Welding Process
Conference paper
https://repositories.lib.utexas.edu//bitstreams/76dc61ef-8418-431e-8cc3-02e6d298394d/download
null
Laser Aided Manufacturing Process (LAMP) can be applied to repair steel die/molds which are currently repaired using traditional welding process in industry. In order to fully understand the advantages of laser deposition repair process over traditional welded-repair process, the mechanical properties such as tensile strength and hardness of H13 tool steel samples produced by these two processes were investigated. The microstructure and fracture surface of the samples were analyzed using optical microscope and SEM (Scanning Electron Microscope). Moreover, depositions on substrates with different shapes were studied to evaluate the performance of LAMP on damaged parts with complicated geometric shape.
null
null
null
null
null
null
['Li, Xiaoxuan', 'Crocker, James E.', 'Geiss, Erik', 'Shaw, Leon L.', 'Marcus, Harris L.', 'Cameron, Thomas B.']
2019-09-23T15:23:05Z
2019-09-23T15:23:05Z
2000
Mechanical Engineering
null
['https://hdl.handle.net/2152/75934', 'http://dx.doi.org/10.26153/tsw/3033']
eng
2000 International Solid Freeform Fabrication Symposium
Open
Restoration
Evaluation of Microstructure and Properties for Multi-Materials Laser Densification of Dental Restoration 159
Conference paper
https://repositories.lib.utexas.edu//bitstreams/15c19fbb-1436-44a4-8bc4-cabd594dfc32/download
null
Traditional dental restorations are produced by the porcelain-fused-to-metal (PFM) process, in which a dental restoration is cast from a metallic alloy and then covered with dental porcelains by several firing processes, which is both labor intensive and expensive. In this paper, the feasibility of dental restorations is investigated using a multi-materials laser densification (MMLD) process. To evaluate the effectiveness of the MMLD process, nickel powders and commercial dental porcelain powders are laser densified using YAG and CO2 lasers respectively. Effects of processing parameters, e.g. laser scanning rate and target temperature, are evaluated and the microstructure of processed nickel and porcelain materials are characterized for the optimization of laser densification. Results indicate that densities of laser processed nickel and dental porcelain are strongly dependent of processing parameters. Fully dense layers are achievable with proper processing conditions.
null
null
null
null
null
null
['Cansizoglu, O.', 'Cormier, D.', 'Harryson, O.', 'West, H.', 'Mahale, T.']
2020-02-28T15:13:56Z
2020-02-28T15:13:56Z
2006
Mechanical Engineering
null
['https://hdl.handle.net/2152/80110', 'http://dx.doi.org/10.26153/tsw/7131']
eng
2006 International Solid Freeform Fabrication Symposium
Open
Powder metallurgy
An Evaluation of Non-Stochastic Lattice Structures Fabricated Via Electron Beam Melting
Conference paper
https://repositories.lib.utexas.edu//bitstreams/0642ebfb-8c89-4b55-b4d3-9ec733cc2a1e/download
null
Metal foam structures have many applications and can be used as structural supports, heat exchangers, shock absorbers, and implant materials. Stochastic metal foams having different cell sizes and densities have been commercially available for a number of years. This paper addresses a different type of foams which are known as non-stochastic foams, or lattice structures. These foams have a well defined repeating unit cell structure rather than the random cell structure in commercially available stochastic foams. The paper reports on preliminary research on the fabrication of non-stochastic Ti-6Al-4V alloy foams using the Electron Beam Melting process. Behavior of the structures in compression, bending, and low cycle repeating load tests are discussed, and recommendations about cell geometry and processing conditions are made.
null
null
null
null
null
null
['Nussbaum, Justin', 'Craft, Garrett', 'Harmon, Julie', 'Crane, Nathan']
2021-10-27T22:29:06Z
2021-10-27T22:29:06Z
2016
Mechanical Engineering
null
https://hdl.handle.net/2152/89633
eng
2016 International Solid Freeform Fabrication Symposium
Open
['heating rates', 'exposure times', 'sintering levels', 'nylon 12', 'selective laser sintering']
Evaluation of Processing Variables in Large Area Polymer Sintering of Single Layer Components
Conference paper
https://repositories.lib.utexas.edu//bitstreams/db3c9c28-1d85-4941-a0c2-666db1e023da/download
University of Texas at Austin
As the additive manufacturing (AM) industry continues to boom, the material palette continues to grow. However, the materials applicable to selective laser sintering (SLS) remains limited. Typically, the scanning laser beam heats each location for milliseconds at a time with a very high heating flux followed by quick cooling. This can create large temperature gradients and high local temperatures. Many polymers will degrade or fail to densify under these conditions. Due to the economic constraints for point processing, little work has been done to evaluate the sintering process with lower intensities, longer exposure times and larger areas than are typical with conventional SLS. We will report on a new method for simultaneously heating large areas with spatially-controlled heat flux. A demonstration system and test material is presented and characterized. It is then used to evaluate the relationships between heating rates, exposure time, and resulting sintering levels for traditional Nylon 12 powders in single layer parts.
null
null
null
null
null
null
['Agarwal, Kuldeep', 'Mathur, Deepanker', 'Shiypuri, Rajiv', 'Lembo, John']
2019-10-24T17:52:25Z
2019-10-24T17:52:25Z
2002
Mechanical Engineering
null
['https://hdl.handle.net/2152/77408', 'http://dx.doi.org/10.26153/tsw/4497']
eng
2002 International Solid Freeform Fabrication Symposium
Open
Prometal
Evaluation of PROMETAL Technique for Application to Dies for Short Run Forgings
Conference paper
https://repositories.lib.utexas.edu//bitstreams/4bdbb249-83a8-4804-812a-da5d98c01735/download
null
Manufacturing of hot forging dies required several steps such as acquisition of material block, shaping it for machining, rough machining the cavity, heat treating, finish machining, grinding and polishing. This process takes several months. Consequently for limited number of parts often required in aerospace industry, forging is being replaced by direct machining of parts. If the die lead times (administrative and manufacturing) could be reduced to weeks instead of months, forging process will become viable for short run forgings. This paper evaluates the PROMETAL technique for dies in forging of aluminum alloys. This evaluation includes frictional, heat transfer and strength characterization. Isothermal and non-isothermal ring tests together with FEM models are used to determine the interface behavior and its effect on metal flow.
null
null
null
null
null
null
['Merschroth, H.', 'Harbig, J.', 'Weigold, M.', 'Geis, J.', 'Kirchner, E.']
2023-04-03T17:32:18Z
2023-04-03T17:32:18Z
2022
Mechanical Engineering
null
['https://hdl.handle.net/2152/117724', 'http://dx.doi.org/10.26153/tsw/44603']
eng
2022 International Solid Freeform Fabrication Symposium
Open
powder bed fusion
Evaluation of Solidification in Powder Bed Fusion Using a High Speed Camera
Conference paper
https://repositories.lib.utexas.edu//bitstreams/03b140d1-8b98-4600-8a5d-9cbb93c2f881/download
null
Powder bed fusion using a laser beam (PBF-LB) [1] enables geometrical design freedom to build parts for optimized functionality. Furthermore, PBF-LB allows microstructural design freedom. By controlling the solidification behavior microstructural adaptions can be made to obtain the full potential of the material. As the solidification rates and the thermal gradient depend on the local part geometry, new data-driven approaches, e.g. machine learning (ML), seem to be suitable for local microstructural adaptions. In this work an evaluation concept to analyze the thermal melt pool characteristics based on a high-speed camera is developed. The thermal radiation intensity of the melt pool is used to derive the thermal gradient and combined with an image rate of 41,000 fps the solidification rate is derived. The developed approach provides local data of the solidification for ML-based process adaptions but also serves for part individual quality assurance tasks.
null
null
null
null
null
null
['Weiss, C.', 'Boedger, C.', 'Schiefer, E.', 'Heussen, D.', 'Haefner, C.L.']
2023-03-30T16:14:22Z
2023-03-30T16:14:22Z
2022
Mechanical Engineering
null
['https://hdl.handle.net/2152/117699', 'http://dx.doi.org/10.26153/tsw/44578']
eng
2022 International Solid Freeform Fabrication Symposium
Open
Laser powder bed fusion
Evaluation of the Ecological Footprint for Parts from AlSi10Mg manufactured by Laser Powder Bed Fusion
Conference paper
https://repositories.lib.utexas.edu//bitstreams/eaaebdc5-c0e7-47c0-a6e7-f6f0324e96d9/download
null
The manufacturing industry contributes immensely to the global emissions and therefore is a key factor that has to be addressed when a more sustainable production is desired. Laser Powder Bed Fusion (LPBF) is an AM technique that offers the possibility to manufacture metal parts in a more material efficient way due to the layer-by-layer build-up. Nevertheless, the processing chain for parts from LPBF contains additional steps like powder atomization, which also influence the ecological footprint of the production chain. Within this work, a life-cycle model for the production step of parts from AlSi10Mg powder material is developed. The model is supplied with data from the powder atomization up to the production step, either by literature, database or experimental measurements during production. The footprint in terms of CO2 emissions is then analyzed and emission-intense steps are identified. Two manufacturing scenarios are considered to evaluate the sensitivity on the emissions.
null
null
null
null
null
null
['Agarwala, Mukesh K.', 'Bourell, David L.', 'Wu, Benny', 'Beaman, Joseph J.']
2018-05-03T18:47:39Z
2018-05-03T18:47:39Z
1993
Mechanical Engineering
doi:10.15781/T29P2WQ0P
http://hdl.handle.net/2152/65058
eng
1993 International Solid Freeform Fabrication Symposium
Open
['SLS process', 'Center for Materials Science and Engineering', 'Department of Mechanical Engineering', 'Rapid Prototyping']
An Evaluation of the Mechanical Behavior of Bronze-NI Composites Produced by Selective Laser Sintering
Conference paper
https://repositories.lib.utexas.edu//bitstreams/ffeac1b8-0d35-44b3-8fda-e63ac22e8ee5/download
null
Mechanical properties of Bronze-Nickel composites produced by Selective Laser Sintering (SLS) were evaluated by constant displacement tension tests. These were studied as a function of SLS process parameters - laser power density, scan speed, scan spacing, scan direction and layer thickness. The strength data was then correlated to the microstructure and the part bulk density. To further enhance the part densities and the mechanical properties, post-SLS sintering was studied. The relationships between SLS process parameters, post-SLS sintering parameters and the resulting microstructures, part bulk density and the mechanical properties will be described.
null
null
null
null
null
null
['Price, Steven', 'Cooper, Ken', 'Chou, Kevin']
2021-10-06T21:30:51Z
2021-10-06T21:30:51Z
8/16/12
Mechanical Engineering
null
['https://hdl.handle.net/2152/88450', 'http://dx.doi.org/10.26153/tsw/15387']
eng
2012 International Solid Freeform Fabrication Symposium
Open
['electron beam additive manufacturing', 'near-infrared thermography', 'powder-based manufacturing']
Evaluations of Temperature Measurements By Near-Infrared Thermography in Powder-Based Electron-Beam Additive Manufacturing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/847dfddf-7941-4fc6-9bd6-75b35838c7b5/download
University of Texas at Austin
Powder-based electron beam additive manufacturing (EBAM) has gained increased usage in different industries. Process monitoring such as temperatures may offer important information. However, temperature measurements in EBAM are challenging because of high temperature ranges, extreme gradients and fast transient response. In this study, temperature measurements during the EBAM process, in particular, around the electron beam scanning area, were attempted using a near-infrared thermal camera. The obtained temperature data demonstrated the feasibility of such a measuring technique. The thermal camera was able to capture the pre-heating, contour melting, and hatch melting events. Further, the achievable spatial resolution is around 12 µm when using a 350 mm lens.
null
null
null
null
null
null
['Moi, Matthias', 'Lindemann, Christian', 'Jahnke, Ulrich', 'Koch, Rainer']
2021-10-11T21:39:29Z
2021-10-11T21:39:29Z
8/16/13
Mechanical Engineering
null
['https://hdl.handle.net/2152/88653', 'http://dx.doi.org/10.26153/tsw/15587']
eng
2013 International Solid Freeform Fabrication Symposium
Open
['Additive Manufacturing', 'event-driven software architecture', 'cost assessment', 'traceability', 'Quality Management']
An Event-Driven Software Architecture for Process Analysis in Additive Manufacturing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/6145b62c-1c0d-4f8f-8f73-f3ccb2d3bb26/download
University of Texas at Austin
Additive Manufacturing is still not commonly accepted as a considerable manufacturing process for serial products. Build rate and cost estimation or even the traceability of parts concerning Quality Management issues is weak. That's also because of the unavailability of adequate software solutions. Self-made solutions with Spreadsheets are often hard to adapt and inflexible in usage. This paper presents a distributed event-driven software architecture for cost assessment and traceability from powder to finished products. Further the approach of event-driven processing for cost calculation following the activity based costing methodology is discussed. The methodology considers arbitrary events (e.g. machine data or market prices) that may have an effect for a more detailed process analysis.
null
null
null
null
null
null
['Gibert, James M.', 'McCullough, Daniel T.', 'Fadel, Georges M.', 'Jonhson, Kenneth E.']
2021-10-05T19:50:15Z
2021-10-05T19:50:15Z
8/15/12
Mechanical Engineering
null
['https://hdl.handle.net/2152/88420', 'http://dx.doi.org/10.26153/tsw/15359']
eng
2012 International Solid Freeform Fabrication Symposium
Open
['ultrasonic consolidation', 'build height', 'support materials', 'tin bismuth', 'candy']
Examination of Build Height in Ultrasonic Consolidation for Foil Width Specimens Using Supports
Conference paper
https://repositories.lib.utexas.edu//bitstreams/d1629479-ad03-4c01-8776-8a40b2555991/download
University of Texas at Austin
Ultrasonic consolidation (UC) is a novel, solid-state, additive manufacturing fabrication process. It consists of ultrasonic joining of thin metal foils and contour milling to directly produce functional components in a variety of geometries. The bond between layers forms when an ultrasonic horn creates a local oscillating stress field at the mating surfaces. It is commonly theorized that the high frequency vibration under pressure produces a metallurgical bond without melting the base material. The mechanism behind the bond is believed to be due to interfacial motion and friction that disrupts surface contaminants, arguably allowing direct metal to metal contact, and producing sufficient stress to induce plastic flow and promote the growth of grains across the mating surfaces. Ignored in this explanation is the role of substrate dimensions on the quality and strength of the joining process. Researchers have previously examined the effective height limitations of the build process, i.e., the limiting height to width ratio of one of the component features being fabricated. This paper extends the experimental work on using support materials to extend build height on specimens using two different candidate materials, tin bismuth, and a mixture of sugar, corn syrup, and water, referred to as “candy”. Tin bismuth and candy the represent the extremes of a tradeoff between convenience and stiffness that a support material must possess.
null
null
null
null
null
null
['Link, Martin', 'Haefele, Tobias', 'Abele, Eberhard']
2021-11-09T16:34:33Z
2021-11-09T16:34:33Z
2018
Mechanical Engineering
null
['https://hdl.handle.net/2152/90107', 'http://dx.doi.org/10.26153/tsw/17028']
eng
2018 International Solid Freeform Fabrication Symposium
Open
['316L', 'steel powder', 'stainless-steel base bodies', 'selective laser melting', 'additive manufacturing', 'conventional manufacturing']
Examination of the Connection Between Selective Laser-Melted Components of 316L Steel Powder on Conventionally Fabricated Base Bodies
Conference paper
https://repositories.lib.utexas.edu//bitstreams/c5b7a910-44ee-4821-be06-88908df06bc6/download
University of Texas at Austin
The advantages of selective laser melting lie in the production of complex, small components in small batches. For large-volume components, the use of additive manufacturing (AM) processes is limited by the available installation space, low build rates, and high material costs. For the production of large and less complex workpieces, conventional manufacturing processes such as milling are more economical. The background of this study was to combine both processes to decrease manufacturing times. For this purpose, a body made of 316L (1.4404) steel powder was printed using selective laser melting on conventionally manufactured stainless-steel base bodies. The use of multi-materials enables optimized machinability in the respective manufacturing process. This paper examines the hardness properties of multi-material samples and uses micrographs to analyze the microstructure of their connection area. A complete connection between hybrid components made of comparable materials was determined.
null
null
null
null
null
null
['Pichler, T.', 'Schleifenbaum, J.H.']
2021-11-18T18:21:16Z
2021-11-18T18:21:16Z
2019
Mechanical Engineering
null
['https://hdl.handle.net/2152/90455', 'http://dx.doi.org/10.26153/tsw/17376']
eng
2019 International Solid Freeform Fabrication Symposium
Open
['process control', 'process parameters', 'geometries', 'thermal imaging', 'Ti6Al4V', 'LPBF']
Examination of the LPBF Process by Means of Thermal Imaging for the Development of a Geometric-Specific Process Control
Conference paper
https://repositories.lib.utexas.edu//bitstreams/f88a0473-ed4b-4406-a4b8-2480b01f2cff/download
University of Texas at Austin
The development of process parameters for the Laser Powder Bed Fusion (LPBF) process is typically carried out by the manufacturing and metallurgical analysis of geometrically primitive test specimens (e.g. cubes). The process parameters identified in this way are used for the manufacturing of parts which are characterized by a high geometric complexity and a combination of solid and filigree component areas. Due to the discrepancy between the parameter development on primitive specimens and applications with complex parts, a geometric-specific process control is to be developed. In the context of this work different sample geometries are manufactured from Ti6Al4V by LPBF and the process is monitored by thermal imaging. The influence between component geometry and process parameters on the thermal behavior is shown.
null
null
null
null
null
null
['Eschey, C.', 'Lutzmann, S.', 'Zaeh, M.F.']
2021-09-28T20:04:51Z
2021-09-28T20:04:51Z
9/18/09
Mechanical Engineering
null
['https://hdl.handle.net/2152/88169', 'http://dx.doi.org/10.26153/tsw/15110']
eng
2009 International Solid Freeform Fabrication Symposium
Open
['Electron Beam Melting', 'powder spreading', 'additive layer manufacturing']
Examination of the Powder Spreading Effect in Electron Beam Melting (EBM)
Conference paper
https://repositories.lib.utexas.edu//bitstreams/f4c0f1e6-cfd3-41c0-8c65-1b33750e950b/download
University of Texas at Austin
In recent years, the scientific and industrial relevance of Electron Beam Melting (EBM) has grown. This is mainly due to the electron beam’s extensive power density and flexible positioning properties. Thus, considerable building rates as well as a favorable part quality can be realized. However, the appearance of transient physical effects constitutes a substantial drawback towards the broader use of the technology. Therefore, experimental examinations are being carried out in order to investigate the effect of sudden powder spreading during beam material interaction. Based on an existing mathematical model, an analytical approach is formulated in order to implement effective counter measures. Hence, a significant increase in process stability is being achieved as the undesirable powder spreading effect is being avoided securely.
null
null
null
null
null
null
['Betts, J. Logan', 'Downs, Will', 'Dantin, Matthew J.', 'Priddy, Matthew W']
2023-02-09T15:42:42Z
2023-02-09T15:42:42Z
2022
Mechanical Engineering
null
['https://hdl.handle.net/2152/117435', 'http://dx.doi.org/10.26153/tsw/44316']
eng
2022 International Solid Freeform Fabrication Symposium
Open
GPU
Examining the GPU Acceleration Speed-Up for Finite Element Modeling of Additive Manufacturing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/c004ad59-d8d5-4f4b-abf5-92eea1458740/download
null
Using a graphics processing unit (GPU) in addition to a central processing unit (CPU) has demonstrated promise for the acceleration of processing-intensive operations such as finite element (FE) simulations. Commercial FE solvers have begun to utilize GPU acceleration for classical multi-physics applications, but the speed-up for additive manufacturing (AM) simulations is not well understood. There is a significant need for GPU acceleration for metal-based AM FE simulations, which are computationally expensive because of the high mesh densities and the large number of time increments employed. This study examines the efficacy of GPU acceleration for Abaqus AM simulations, where benchmark simulations using a sequentially coupled FE thermo- mechanical model are run both with and without GPU acceleration. The speed-up is compared across the AM process for the thermal and mechanical analysis. In this study, GPU acceleration provided the ability to decrease simulation runtime by two-to-four times on 4-8 CPU cores, and one-to-two times on 16-32 CPU cores.
null
null
null
null
null
null
['Barclift, Michael W.', 'Williams, Christopher B.']
2021-10-06T22:31:22Z
2021-10-06T22:31:22Z
8/15/12
Mechanical Engineering
null
['https://hdl.handle.net/2152/88460', 'http://dx.doi.org/10.26153/tsw/15397']
eng
2012 International Solid Freeform Fabrication Symposium
Open
['Objet', 'PolyJet', 'design of experiments', '3D printing']
Examining Variability in the Mechanical Properties of Parts Manufactured via PolyJet Direct 3D Printing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/b1a95fb2-f9fe-4c3d-8764-3a0f5a5ee387/download
University of Texas at Austin
In Objet’s PolyJet process, part layers are created by selectively inkjetting photopolymers onto a build substrate and then cured with ultraviolet lamps. With an eye towards using PolyJet as a manufacturing process to fabricate end-use products, the authors examine the sensitivity of part material properties to variation in process parameters. Specifically, a design of experiments is conducted using a full-factorial design to analyze the effects of three parameters on the specimens’ tensile strength and tensile modulus: the in-build plane part orientation (X-Y), the out-of-build plane part orientation (Z), and the distance between specimens. Results show that part spacing has the largest effect on the tensile strength, but the three parameters produced no statistically significant effects on the tensile modulus. Orienting specimens in XZ orientation with minimal part spacing resulted in the highest tensile strength and modulus. Whereas, orienting specimens in the YZ orientation at the farthest part spacing led to the lowest mechanical properties.
null
null
null
null
null
null
['Sudbury, Zeke', 'Duty, Chad', 'Kunc, Vlastimil']
2021-11-02T18:04:42Z
2021-11-02T18:04:42Z
2017
Mechanical Engineering
null
https://hdl.handle.net/2152/89845
eng
2017 International Solid Freeform Fabrication Symposium
Open
['material property space map', 'functionally graded materials', 'big area additive manufacturing', "Ashby's concept"]
Expanding Material Property Space Maps with Functionally Graded Materials for Large Scale Additive Manufacturing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/bb59ac73-d1cf-46c8-8bdb-382c068514ff/download
University of Texas at Austin
Big Area Additive Manufacturing (BAAM) is a large scale extrusion-based print system that exceeds the throughput of conventional printers by five hundred times. In addition, BAAM uses pelletized feedstocks, which allows for site-specific definition of material composition and provides an unprecedented variety of material options. This study applies Ashby’s concept of a material property space map to a variety of materials suitable for printing on BAAM. Ashby maps plot the performance of various materials across multiple parameters (such as strength, density, stiffness, etc) allowing for direct comparison of non-dimensional performance criteria. This study uses Ashby maps to identify opportunities for the use of functionally graded materials on BAAM to achieve structural performance not yet available with conventional printers and homogeneous materials.
null
null
null
null
null
null
['Lopes, Amit', 'Navarrete, Misael', 'Medina, Francisco', 'Palmer, Jeremy', 'MacDonald, Eric', 'Wicker, Ryan']
2020-03-05T19:43:41Z
2020-03-05T19:43:41Z
9/14/06
Mechanical Engineering
null
['https://hdl.handle.net/2152/80148', 'http://dx.doi.org/10.26153/tsw/7169']
eng
2006 International Solid Freeform Fabrication Symposium
Open
rapid prototyping
Expanding Rapid Prototyping for Electronic Systems Integration of Arbitrary Form
Conference paper
https://repositories.lib.utexas.edu//bitstreams/7253996a-e186-4bbe-b18b-f25bca92b0c3/download
null
An innovative method for rapid prototyping (RP) of electronic circuits with components characteristic of typical electronics applications was demonstrated using an enhanced version of a previously developed hybrid stereolithography (SL) and direct write (DW) system, where an existing SL machine was integrated with a three-axis DW fluid dispensing system for combined arbitrary form electronic systems manufacturing. This paper presents initial efforts at embedding functional electronic circuits using the hybrid SL/DW system. A simple temperature-sensitive circuit was selected, which oscillated an LED at a frequency proportional to the temperature sensed by the thermistor. The circuit was designed to incorporate all the required electronic components within a 2.5” x 2” x 0.5” SL part. Electrical interconnects between electronic components were deposited on the SL part with a DW system using silver conductive ink lines. Several inks were deposited, cured, and tested on a variety of SL resin substrates, and the E 1660 ink (Ercon Inc, Wareham, MA) was selected due to its measured lowest average resistivity on the SL substrates. The finished circuit was compared with Printed Circuit Board (PCB) technology for functionality. The electronic components used here include a low voltage battery, LM 555 timer chip, resistors, a thermistor, capacitors, and Light Emitting Diodes (LEDs). This circuit was selected because it (1) represented a simple circuit combining many typically used electronic components and thus provided a useful demonstration for integrated electronic systems manufacturing applicable to a wide variety of devices, and (2) provided an indication of the parasitic resistances and capacitances introduced by the fabrication process due to its sensitivity to manufacturing variation. The hybrid technology can help achieve significant size reductions, enable systems integration in atypical forms, a natural resistance to reverse engineering and possibly increase maximum operating temperatures of electronic circuits as compared to the traditional PCB process. This research demonstrates the ability of the hybrid SL/DW technology for fabricating combined electronic systems for unique electronics applications in which arbitrary form is a requirement and traditional PCB technology cannot be used.
null
null
null
null
null
null
['Roberson, D.A.', 'Shemelya, C.M.', 'MacDonald, E.', 'Wicker, R.B.']
2021-10-13T19:33:07Z
2021-10-13T19:33:07Z
2014
Mechanical Engineering
null
['https://hdl.handle.net/2152/88769', 'http://dx.doi.org/10.26153/tsw/15703']
eng
2014 International Solid Freeform Fabrication Symposium
Open
['3D printing', 'materials characterization', 'polymer matrix composites']
Expanding the Applicability of FDM-type Technologies Through Materials Development
Conference paper
https://repositories.lib.utexas.edu//bitstreams/30194075-adab-4942-a703-68dd20871094/download
University of Texas at Austin
Currently, the most common form of additive manufacturing is material extrusion 3D printing (ME3DP) based on fused deposition modeling (FDM®) technology which relies upon a thermoplastic monofilament as a base material for the fabrication of three dimensional objects. The dependence on thermoplastics as a feedstock by ME3DP platforms limits the applicability of this additive manufacturing method. A clear-cut path towards greater applicability is the introduction of novel materials with diverse physical properties which maintain compatibility with 3D printing platforms based on FDM® technology. The work in this paper presents efforts in the development of polymer matrix composites (PMC)s and polymer blends based on acrylonitrile butadiene styrene (ABS) and polycarbonate (PC), two thermoplastic materials commonly used by FDM®-type platforms. Mechanical testing and fractography via scanning electron microscopy (SEM) were the two main metrics used to characterize these new material systems. Overcoming barriers to the manufacturing of these novel 3D-printable materials systems is also presented.
null
null
null
null
null
null
['Lough, Cody S.', 'Landers, Robert G.', 'Bristow, Douglas A.', 'Drallmeier, James A.', 'Brown, Ben', 'Kinzel, Edward C.']
2021-12-07T17:25:26Z
2021-12-07T17:25:26Z
2021
Mechanical Engineering
null
['https://hdl.handle.net/2152/90729', 'http://dx.doi.org/10.26153/tsw/17648']
eng
2021 International Solid Freeform Fabrication Symposium
Open
['thermal modeling', 'superposition', 'laser powder bed fusion', 'LPBF']
Experiment Based Superposition Thermal Modeling of Laser Powder Bed Fusion
Conference paper
https://repositories.lib.utexas.edu//bitstreams/84948207-9068-416a-804a-06c9ca36037a/download
University of Texas at Austin
This paper evaluates experiment-based superposition thermal modeling for Laser Powder Bed Fusion (LPBF) with a pulsed laser. An analytical pulsed laser thermal model establishes the modeling procedure. The framework inverts a powder bed’s single pulse temperature response from experimental spatiotemporal Short-Wave Infrared (SWIR) camera data. Superimposing this response along a scan path simulates multi-pulse LPBF. Results show the experimentally informed superposition model rapidly and accurately predicts a layer’s temperature history. The model has applications in correction of thermally driven LPBF errors and in-situ part qualification.
null
null
null
null
null
null
['Kjer, Magnus Bolt', 'Zwicker, Moritz Reinhard Ludwig', 'Nadimpalli, Venkata Karthik', 'Andersen, Sebastian Aagaard', 'Pedersen, David Bue']
2023-01-27T14:27:33Z
2023-01-27T14:27:33Z
2022
Mechanical Engineering
null
['https://hdl.handle.net/2152/117340', 'http://dx.doi.org/10.26153/tsw/44221']
eng
2022 International Solid Freeform Fabrication Symposium
Open
gas flow
Experimental Analysis and Optimization of Gas Flow in an Open-Architecture Metal L-PBF System
Conference paper
https://repositories.lib.utexas.edu//bitstreams/0662b13b-ef7f-46e2-a86e-918096f117cb/download
null
A sensor platform for experimental in-situ characterization of metal laser powder bed fusion (L- PBF) is developed and used to analyze the gas flow across the powder bed. The gas flow in metal L-PBF is crucial to attaining transient and spatially consistent results. The gas flow removes spatter from the welding process as well as the plume consisting of metal condensate. Defects like porosity will result from these process byproducts not being removed. A CNC gantry with a flow sensor mounted measured the gas velocity across the process area. The automated measurements were analyzed and used to improve the gas flow by changing the inlet geometry. The method can be used as a supplement to computational fluid dynamics, as well as a calibration tool for simulations, to improve the efforts toward better models of the metal L-PBF process.
null
null
null
null
null
null
['Alkunte, Suhas', 'Fidan, Ismail', 'Hasanov, Seymur']
2023-01-20T16:38:53Z
2023-01-20T16:38:53Z
2022
Mechanical Engineering
null
['https://hdl.handle.net/2152/117263', 'http://dx.doi.org/10.26153/tsw/44144']
eng
2022 International Solid Freeform Fabrication Symposium
Open
['Additive Manufacturing', 'Functionally Graded Materials (FGM)', 'Tensile', 'Fatigue']
Experimental Analysis of Functionally Graded Materials produced by Fused Filament Fabrication
Conference paper
https://repositories.lib.utexas.edu//bitstreams/2fd4ce0e-25fc-43bd-bef3-c6f7bd2a4191/download
null
Multi-material additive manufacturing has grabbed tremendous attention in the research community. In this investigation, a multi-material single extrusion system was used to fabricate the combination of chopped carbon fiber reinforced Polyethylene Terephthalate Glycol (CF- PETG) and Thermoplastic Polyurethane (TPU) materials with gradient transition for a more robust material interface. Various patterns such as the 20, 40, 60, and 80% by volume blend of CF-PETG and TPU materials are designed, printed, and analyzed to understand their tensile and fatigue behaviors. Tensile–tensile fatigue tests with a stress ratio of 0.1 were performed on each specimen at 80% of UTS. The characterization of functionally gradient material interface and direct transition patterns were conducted for comparison. The results showed that gradient change in material concentrations from soft to hard material has significantly enhanced the interface strength.
null
null
null
null
null
null
['Gribbins, Cassandra', 'Steinhauer, Heidi M.']
2021-10-19T15:29:12Z
2021-10-19T15:29:12Z
2014
Mechanical Engineering
null
https://hdl.handle.net/2152/89300
eng
2014 International Solid Freeform Fabrication Symposium
Open
['acrylonitrile butadiene styrene', 'ABS living hinge', 'plastic behavior', 'additive manufacturing']
Experimental Analysis on an Additively Manufactured ABS Living Hinge
Conference paper
https://repositories.lib.utexas.edu//bitstreams/5b492148-8868-45d2-950f-a3b6a938d4a9/download
University of Texas at Austin
A study on the plastic behavior of an additively manufactured acrylonitrile butadiene styrene (ABS) living hinge was conducted using a MakerBot 2X. Initial research included numerical and analytical linear analyses on a typical living hinge design. This paper introduces the portion of the research that explores the application of traditional design practices to entry-level additive manufacturing machines. Tensile testing for material properties was conducted to refine the numerical model. Experimental rotational testing was conducted for data on the non-linear, plastic behavior experienced during application. Verification of the numerical model with experimental results will be used to guide future work on exploring alternate design geometries that leverage the advantages of additive manufacturing’s design freedom for smoother stress distribution on the hinge.
null
null
null
null
null
null
['Fotovvati, B.', 'Shrestha, S.', 'Ferreri, N.', 'Duanmu, N.']
2024-03-26T20:47:24Z
2024-03-26T20:47:24Z
2023
Mechanical Engineering
null
['https://hdl.handle.net/2152/124405', 'https://doi.org/10.26153/tsw/51013']
en_US
2023 International Solid Freeform Fabrication Symposium
Open
['selective laser melting', 'area printing', 'thermo-fluid modeling', 'Inconel 718', 'M300 maraging steel']
Experimental and Computational Study of Area Printing™ Additive Manufacturing: Inconel 718 and M300 Maraging Steel Density Improvement
Conference paper
https://repositories.lib.utexas.edu//bitstreams/c2f7388e-9b9a-4db2-801c-e609b537f8a4/download
University of Texas at Austin
The low manufacturing speed of laser-powder bed fusion (LPBF) additive manufacturing has hindered its adoption in conventional manufacturing methods. Large-area pulsed laser powder bed fusion (LAPBF), also known as "Area Printing™", has addressed this limitation by replacing the point laser with a large-area pulsed laser. Each pulse melts a region of the powder bed in the order of square millimeters, which enables scalability without the sacrifice of resolution and high throughput at an equivalent or better quality (in part due to a lack of spatter) when compared to conventional LPBF methods. In this study, process parameters are optimized to achieve near-fulldensity parts, and a computational model is developed to understand the multi-physics governing the process. It is observed that the shallow depth and high aspect ratio of the melt pool lead to a unidirectional solidification front extending along the build direction where grains grow epitaxially, and highly directional microstructures are created.
null
null
null
null
null
null
['Dong, Guoying', 'Ding, Yuchen', 'Teawdeswan, Ladpha', 'Luo, Chaoqian', 'Yu, Kai']
2023-02-24T14:56:54Z
2023-02-24T14:56:54Z
2022
Mechanical Engineering
null
['https://hdl.handle.net/2152/117527', 'http://dx.doi.org/10.26153/tsw/44407']
eng
2022 International Solid Freeform Fabrication Symposium
Open
['Additive manufacturing', 'Finite Element Analysis', 'Heterogeneous Structure', 'Lattice Structure']
Experimental and Numerical Analysis of Lattice Structures with Different Heterogeneities
Conference paper
https://repositories.lib.utexas.edu//bitstreams/a6dff8f4-c725-496d-9534-f364f366767c/download
null
Lattice structures with optimized material distributions can achieve unique mechanical properties such as high stiffness-to-weight ratio. However, the numerical analysis of the mechanical properties of heterogeneous lattice structures is challenging. In this research, three numerical approaches, including the beam element model, tetrahedral element model, and two- stage homogenization model, were used to predict the stiffness of lattice structures with different heterogeneities. Compression tests were conducted to evaluate the accuracy of the simulation results of each numerical approach. It was found that the accuracy of the numerical model varies with the increasing of heterogeneities. The beam element model significantly underestimated the stiffness. The tetrahedral element model is the most accurate, but the computational cost is extremely higher than others. The results also indicated that, although the homogenization-based numerical model can substantially reduce the computational cost, the accuracy can be compromised due to the heterogeneity of lattice structures.
null
null
null
null
null
null
['Pokkalla, Deepak Kumar', 'Turner White, Brandon', 'Wang, Jier', 'Spencer, Ryan', 'Panesar, Ajit', 'Kim, Seokpum', 'Vaidya, Uday']
2024-03-27T04:00:11Z
2024-03-27T04:00:11Z
2023
Mechanical Engineering
null
['https://hdl.handle.net/2152/124480', 'https://doi.org/10.26153/tsw/51088']
en_US
2023 International Solid Freeform Fabrication Symposium
Open
['triply periodic minimal surface', 'lattice structures', 'additive manufacturing']
Experimental and Numerical Investigations on Dynamic Mechanical Properties of TPMS Structures
Conference paper
https://repositories.lib.utexas.edu//bitstreams/7ca63eef-e677-4b31-8b52-61f59e7e4084/download
University of Texas at Austin
Triply Periodic Minimal Surface (TPMS) lattice structures have been of increasing interest due to their light weighting, enhanced mechanical properties, and energy absorption characteristics for automotive and biomedical applications. With the advent of additive manufacturing and geometric modeling software, TPMS lattices with complex geometries can be realized. In this work, TPMS lattice structures were fabricated with PLA using fused filament fabrication (FFF) and their dynamic properties are characterized through drop tower experiments. Although lightweight TPMS lattices are beneficial for their impact absorption capability, most of the existing works are limited to quasi-static compression, and dynamic impact tests are rarely performed. The current study investigates the stress-strain and energy absorption characteristics of TPMS lattices through drop tower testing and numerical modeling. Finite element modeling for TPMS lattices is carried out to validate the experimental responses. The mechanical properties, deformation, and failure mechanisms of TPMS lattices under dynamic impact are summarized for potential future applications.
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['Santosa, James', 'Jing, Dejun', 'Das, Suman']
2019-10-30T16:53:27Z
2019-10-30T16:53:27Z
2002
Mechanical Engineering
null
['https://hdl.handle.net/2152/78192', 'http://dx.doi.org/10.26153/tsw/5281']
eng
2002 International Solid Freeform Fabrication Symposium
Open
Multi-Material Deposition
Experimental and Numerical Study on the Flow of Fine Powders from Small-Scale Hoppers Applied to SLS Multi-Material Deposition-Part I
Conference paper
https://repositories.lib.utexas.edu//bitstreams/bb723c59-40d9-4dea-ba31-e76e88bea4b7/download
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We present experimental guidelines for the delivery of powders under 100µm through hopper-nozzle orifice diameters on the order of 1mm. Small-scale hoppers will be incorporated into an SLS powder deposition system for creating thin layers of multiple powdered materials in a patterned bed. This is a preliminary investigation on the flow behavior for selected orifice diameters and particle sizes under gravity or low pressure-assisted flow conditions. A method for numerically modeling the gas-particle behavior in hopper-nozzles is presented and conditions for achieving continuous mass flow rates are demonstrated.
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['Bansal, R.', 'Acharya, R.', 'Gambone, J.J.', 'Das, S.']
2021-10-05T13:51:58Z
2021-10-05T13:51:58Z
2011
Mechanical Engineering
null
['https://hdl.handle.net/2152/88372', 'http://dx.doi.org/10.26153/tsw/15311']
eng
2011 International Solid Freeform Fabrication Symposium
Open
['scanning laser epitaxy', 'Georgia Institute of Technology', 'nickel-based superalloys']
Experimental and Theoretical Analysis of Scanning Laser Epitaxy Applied to Nickel-Based Superalloys
Conference paper
https://repositories.lib.utexas.edu//bitstreams/e3539553-f62d-4ab0-ad05-07f891c2c979/download
University of Texas at Austin
This paper reports on the experimental development and the theoretical analysis of the scanning laser epitaxy (SLE) process that is currently being investigated and developed at the Georgia Institute of Technology. SLE is a laser-based manufacturing process for deposition of equiaxed, directionally solidified and single-crystal nickel superalloys onto superalloy substrates through the selective melting and re-solidification of superalloy powders. The thermal modeling of the system, done in a commercial CFD software package, simulates a heat source moving over a powder bed and considers the approximate change in the property values for consolidating CMSX-4 nickel superalloy powder. The theoretical melt depth is obtained from the melting temperature criteria and the resulting plots are presented alongside matching experimental micrographs obtained through cross-sectional metallography. The influence of the processing parameters on the microstructural evolution, as evidenced through observations made from the micrographs, is discussed.
This work is sponsored by the Office of Naval Research, through grants N00173-07-1-G031 and N00014-10-1-0526.
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Yang, Li
2021-10-13T20:36:49Z
2021-10-13T20:36:49Z
2014
Mechanical Engineering
null
['https://hdl.handle.net/2152/88780', 'http://dx.doi.org/10.26153/tsw/15714']
eng
2014 International Solid Freeform Fabrication Symposium
Open
['3D reticulate cellular structure', '3D octahedral cellular structure', 'additive manufacturing']
Experimental Assisted Design Development for a 3D Reticulate Octahedral Cellular Structure using Additive Manufacturing
Conference paper
https://repositories.lib.utexas.edu//bitstreams/2b8e6204-1d9a-4e57-bc22-34aede4f0579/download
University of Texas at Austin
Traditionally it has been difficult to develop and verify designs for 3D reticulate cellular structure. Additive manufacturing provided a feasible alternative for this challenge. In this work, a 3D octahedral cellular structure was designed and investigated. Using a combined method of simulation and experimentation, the mechanical properties of the structures were evaluated. It was found that the cellular structure exhibits unusual size effect that is highly predictable by simulation and experimentation. This work established the design-property mapping for the octahedral cellular structure for further design development, and demonstrated the feasibility of applying this type of structure in sandwich panel applications.
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['Dibua, Obehi G.', 'Yuksel, Anil', 'Roy, Nilabh K.', 'Foong, Chee S.', 'Cullinan, Michael']
2021-11-11T16:48:01Z
2021-11-11T16:48:01Z
2018
Mechanical Engineering
null
['https://hdl.handle.net/2152/90245', 'http://dx.doi.org/10.26153/tsw/17166']
eng
2018 International Solid Freeform Fabrication Symposium
Open
['nanoparticle', 'sintering time', 'calibration', 'simulation', 'microscale selective laser sintering']
Experimental Calibration of Nanoparticle Sintering Simulation
Conference paper
https://repositories.lib.utexas.edu//bitstreams/cee129c6-061a-447d-9bd8-e669184a9c5c/download
University of Texas at Austin
Microscale Selective Laser Sintering models have been built as a basis to predict the properties of sintered nanoparticles under isothermal heating. These models use Phase Field Modelling (PFM) to track the diffusion of nanoparticles, resulting in properties such as the change in relative density and shrinkage of the sintered bed with time. To ensure the accuracy of these PFM models, experimental validation has to be done. This paper presents the experimental procedure and results for isothermally heating nanoparticles up to 450 – 600°C, at sintering times varying from 1 to 45 minutes. Measurement uncertainties are calculated from deviations in calculating the density. Experimental results from this process are then used to calibrate the simulation to determine the number of simulation timesteps which correspond to a minute of physical time. The calibration constant derived is then used to map simulation constants to physical constants. These constants are later compared to bulk properties.
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