ccm/sff-papers · Datasets at Hugging Face

['Zhang, Xinchang', 'Pan, Tan', 'Li, Wei', 'Liou, Frank']

2021-11-11T15:29:01Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90220', 'http://dx.doi.org/10.26153/tsw/17141']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['direct metal deposition', 'repair', 'co-based alloy', 'tool steel']

Experimental Characterization of a Direct Metal Deposited Cobalt-Based Alloy on Tool Steel for Component Repair

Conference paper

https://repositories.lib.utexas.edu//bitstreams/13a9aacd-233a-4ab4-bf2b-b49b77148657/download

University of Texas at Austin

Die casting dies made of tool steel is subject to impact, abrasion and cyclic thermo-mechanical loading that delivers damage such as wear, corrosion, and cracking. To repair such defects, materials enveloping the damage need to be machined and refilled. In this study, V-shape defects with varied sidewall inclination angles were prepared on H13 tool steel substrates and refilled with cobalt-based alloy using direct metal deposition (DMD) for superior hardness and wear resistance. The microstructure of rebuild samples was characterized using an optical microscope (OM) and scanning electron microscope (SEM). Elemental distribution from the substrate to deposits was analyzed using energy dispersive spectrometry (EDS). Mechanical properties of repaired samples were evaluated by tensile test and microhardness measurement. Fracture mechanism in tensile testing was analyzed by observing the fracture surface. The experiment reveals that V-shape defects with sidewall beyond certain angles can be successfully remanufactured. The deposits were fully dense and free of defects. The microstructure and tensile test confirm the solid bonding along the interface. The tensile test shows the mean ultimate tensile strength (UTS) of repaired samples is approximated 620 MPa, where samples fractured at the deposits region. Hardness measurement reveals the hardness of deposits is around 810 HV which is much higher than that of the substrate.

null

['Meachum, J. Mark', "O'Rourke, Amanda", 'Yang, Yong', 'Fedorov, Andrei G.', 'Degertekin, F. Levent', 'Rosen, David W.']

2021-09-29T20:30:54Z

2009-09

Mechanical Engineering

null

['https://hdl.handle.net/2152/88216', 'http://dx.doi.org/10.26153/tsw/15157']

eng

2009 International Solid Freeform Fabrication Symposium

Open

['Additive Manufacturing via Microarray Deposition', 'printed fluids', 'high-viscosity production materials', 'piezoelectrically-driven ultrasonic printhead', 'droplet ejection quality']

Experimental Characterization of High Viscosity Droplet Ejection

Conference paper

https://repositories.lib.utexas.edu//bitstreams/488e7044-9c9d-432a-b1d8-a3d080948549/download

University of Texas at Austin

Additive Manufacturing via Microarray Deposition (AMMD) expands the allowable range of physical properties of printed fluids to include important, high-viscosity production materials (e.g., polyurethane resins). This technique relies on a piezoelectrically-driven ultrasonic printhead that generates continuous streams of droplets from 45 mm orifices while operating in the 0.5 to 3.0 MHz frequency range. Unique to this new printing technique are the high frequency of operation, use of fluid cavity resonances to assist ejection and acoustic wave focusing to generate the pressure gradient required to form and eject droplets. Specifically, we found that peaks in the ejection quality corresponded to predicted device resonances. Our results indicate that the micromachined ultrasonic print-head is able to print fluids up to 3000 mN-s/m2, far above the typical printable range.

null

['Álvarez-Trejo, A.', 'Cuan-Urquizo, E.', 'Roman-Flores, A.']

2024-03-27T15:35:18Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124482', 'https://doi.org/10.26153/tsw/51090']

en

2022 International Solid Freeform Fabrication Symposium

Open

['lattice beams', 'Bezier curve', 'fused filament fabrication', 'additive manufacturing', '3D printing']

EXPERIMENTAL CHARACTERIZATION OF THE MECHANICAL PROPERTIES OF 3D PRINTED BÉZIER-BASED LATTICE BEAMS

Conference paper

https://repositories.lib.utexas.edu//bitstreams/0c0b73a9-1a86-4baf-8ce2-756386e1fb24/download

University of Texas at Austin

Architected materials are widely used in additive manufacturing to reduce weight. The controlled arrangement of material allows to tailor their mechanical properties by tuning their geometrical parameters. A parametrization based on cubic Bézier curves is employed here to generate lattice beams by changing the position of a free control point. Two topologies with the same volume fraction and base curve for the lattice constituent elements at different positions are studied and compared. Lattice beams are manufactured via Fused Filament Fabrication of polylactic acid. The effective stiffness and yield stress of these lattice beams is analyzed experimentally using three-point bending tests. Adjusting the control point location leads to tailoring the effective mechanical properties of the lattice beams. This methodology leads to the synthesis of architected topologies with customized mechanical properties.

null

['Obielodan, J.O.', 'Janaki Ram, G.D.', 'Stucker, B.E.']

2021-09-23T21:42:25Z

9/10/08

Mechanical Engineering

null

['https://hdl.handle.net/2152/88028', 'http://dx.doi.org/10.26153/tsw/14969']

eng

2008 International Solid Freeform Fabrication Symposium

Open

['ultrasonic consolidation', 'foil joints', 'defect free structural members']

An Experimental Determination of Optimum Foil Joint Conditions for Structural Parts Fabricated by Ultrasonic Consolidation

Conference paper

https://repositories.lib.utexas.edu//bitstreams/66bc9591-94d2-45d1-bcc8-0c3a1bff58cf/download

null

This paper describes an investigation of the optimum conditions necessary to eliminate defects at foil joints in parts fabricated by ultrasonic consolidation. Tensile test specimens were fabricated with different foil joint conditions of varying degrees of overlap in the deposition layers. They were subjected to tensile tests to determine their mechanical properties. Microstructures of samples were also studied. Experimental results show correlations between foil joint condition and mechanical strength. Sample microstructures also show correlations between the bonding qualities of the foil joints and the strengths obtained. The study highlights an important process parameter to control for fabrication of defect free structural members by ultrasonic consolidation.

null

['Gonzalez, R.', 'Stucker, B.']

2021-09-28T19:12:20Z

2009-09

Mechanical Engineering

null

['https://hdl.handle.net/2152/88157', 'http://dx.doi.org/10.26153/tsw/15098']

eng

2009 International Solid Freeform Fabrication Symposium

Open

['ultrasonic consolidation', 'Stainless Steel structures', 'parameter optimization', 'Stainless Steel 316L annealed']

Experimental Determination of Optimum Parameters for Stainless Steel 316L Annealed Ultrasonic Consolidation

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d0ed9401-f047-4d64-ba56-ccf442e96c2a/download

University of Texas at Austin

Ultrasonic consolidation is being investigated for building Stainless Steel structures. In this study, parameter optimization for ultrasonic consolidation of Stainless Steel 316L annealed is assessed by evaluating experimental factors of oscillation amplitude, welding speed, normal force and temperature. An L-16 Taguchi design was used to establish the statistical significance of these factors and identify the combination of processing parameters that maximizes linear welding density. Optical microscopy was performed to investigate bond quality.

null

['Ye, Junyang', 'Babazadeh-Naseri, Ata', 'Fregly, Benjamin J.', 'Higgs III, C. Fred']

2024-03-27T15:37:19Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124483', 'https://doi.org/10.26153/tsw/51091']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['hierarchical lattices', 'manufacturing defects', 'digital image correlation', 'experimental', 'functional graded lattice', 'micro-CT', 'Ti-6Al-4V']

EXPERIMENTAL EVALUATION OF HIERARCHICAL FUNCTIONALLY GRADED LATTICES USING DIGITAL IMAGE CORRELATION AND MICRO-CT

Conference paper

https://repositories.lib.utexas.edu//bitstreams/13a71709-5b7d-46a0-aea8-88ca243f9a1a/download

University of Texas at Austin

Hierarchical meta-materials based on functionally-graded lattices (FGLs) have the benefit of customizable material properties. However, the effects of sharp transitions on the effective properties of FGLs have yet to be evaluated. This experimental study focused on characterizing the compressive properties of hierarchical FGLs built with smooth or sharp gradings. A total of 12 samples were 3D-printed in Ti-6Al-4V alloy and tested in axial compressive loading. Digital image correlation (DIC) was used to measure displacements and deformations. The 3D-printing quality of FGLs was also evaluated by micro-CT imaging of 5 samples. The results showed that the cross-sectional areas of struts in FGLs with sharp transitions were 26% smaller than uniform lattices and FGLs with smooth transitions. Compression testing also confirmed a lower average elastic modulus in FGLs with sharp gradings. These results will provide insights for incorporating adjustment factors to account for the loss of strength in FGLs.

null

['Goel, Abhishek', 'Bourell, David']

2021-09-30T13:26:06Z

9/23/10

Mechanical Engineering

null

['https://hdl.handle.net/2152/88233', 'http://dx.doi.org/10.26153/tsw/15174']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['room temperature infiltration', 'Selective Laser Sintering', 'electrochemical infiltration', 'metallic matrix composites']

Experimental feasibility of Electrochemical Infiltration of Laser Sintered Preforms

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1283db39-2301-453d-8786-e8af106a0bdd/download

University of Texas at Austin

This research deals with the experimental feasibility of room temperature infiltration of Selective Laser Sintered preforms with metals. The existing principles of electrochemical deposition techniques were adapted and modified for carrying out the infiltration at low temperatures. Electroless and electrolytic deposition processes were adapted and modified to carry out metal ion infiltration and deposition within interconnected pores. The electrolytic infiltration process was modified by inserting a conductive graphite cathode in the center to draw the positive nickel ions through the interconnected porous network and to deposit them on the pore walls. Forced diffusion method was also attempted by forcing the electrolyte through the preform at high pressures. One of the major benefits of electrochemical infiltration is low processing temperature. Low temperature reduces both energy consumption and associated carbon-footprint and also minimizes undesirable structural changes. Both conductive and non-conductive preforms may be electrochemically infiltrated, and MMCs produced by this method have potential for use in structural applications. This research is sponsored by the National Science Foundation, Grant CMMI-0926316.

null

['Zhao, Xiayun', 'Wang, Jenny M.', 'Zhao, Changxuan', 'Jariwala, Amit', 'Rosen, David W.']

2021-10-28T19:56:11Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89685

eng

2016 International Solid Freeform Fabrication Symposium

Open

['exposure controlled projection lithography', 'interferometric curing monitoring and measurement', 'ECPL', 'ICM&M', 'in-situ', 'process accuracy']

Experimental Implementation and Investigation of Real-Time Metrology for Exposure Controlled Projection Lithography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1010dc0b-d443-4bfa-b144-051d245abbbf/download

University of Texas at Austin

Exposure Controlled Projection Lithography (ECPL) is a stereolithography based process, curing photopolymer parts on a stationary substrate. To improve the process accuracy with closed-loop control, an in-situ interferometric curing monitoring and measurement (ICM&M) system was developed to infer the output of cured height. The previously reported ICM&M method incorporated a sensor model and online parameter estimation algorithms based on instantaneous frequency. In this paper, to validate the ICM&M method, an application program was created in MATLAB to integrate the ECPL and ICM&M systems and to acquire and analyze interferograms online. Given the limited computing power, the interferogram analysis is performed offline. Experiments were performed curing square samples by varying exposure time and intensity. They show that the ICM&M can provide a cost-effective metrology for cured heights with excellent accuracy and reliability, and decent capability of estimating lateral dimensions. The offline ICM&M is a convincing demonstration and benchmark for the real-time ICM&M metrology.

null

['Iyibilgin, Osman', 'Yigit, Cemil']

2021-10-12T18:13:41Z

2013

Mechanical Engineering

null

['https://hdl.handle.net/2152/88711', 'http://dx.doi.org/10.26153/tsw/15645']

eng

2013 International Solid Freeform Fabrication Symposium

Open

['cellular lattice structures', 'Fused Deposition Modeling', 'compressive properties', 'unit cells']

Experimental Investigation of Different Cellular Lattice Structures Manufactured by Fused Deposition Modeling

Conference paper

https://repositories.lib.utexas.edu//bitstreams/00d32033-c5b4-4167-b86b-33a19f9eff52/download

University of Texas at Austin

Experimental tests were conducted to evaluate the compressive properties (yield strength and compressive modulus) and build time for five different cellular lattice structures fabricated by the Fused Deposition Modeling (FDM) process. The lattice structures had repeating unit cells, and the shapes of the unit cell under study included honeycomb, square, diamond, triangle, and circle. Test specimens were manufactured by a Stratasys Fortus 400mc machine using ABS (Acrylonitrile Butadiene Styrene) as the part material. The five different lattice structures were compared with each other and also with the sparse and sparse-double dense build styles that are directly available from the Fortus machine. Honeycomb structure was found to have the best compression properties for the same porosity, although the differences among the different lattice structures were small (<7%). All of these lattice structures were found to have much higher strength than the specimens with the same porosity built using the sparse and sparse-double dense styles. However, the various lattice structures required significantly longer build times than the sparse and sparse-double dense builds. For the honeycomb structure, our investigation also included the effects of porosity and cell size. Higher porosity led to lower compression strength but shorted build time. For the same porosity, the yield strength could be increased and the build time shortened simultaneously by having a certain cell size.

null

['Zhao, Xiyue', 'Mason, Michael S.', 'Huang, Tieshu', 'Leu, Ming C.', 'Landers, Robert G.', 'Hilmas, Gregory E.', 'Easley, Samuel J.', 'Hayes, Michael W.']

2020-03-09T14:11:17Z

9/4/07

Mechanical Engineering

null

['https://hdl.handle.net/2152/80181', 'http://dx.doi.org/10.26153/tsw/7200']

eng

2007 International Solid Freeform Fabrication Symposium

Open

Freeze-form Extrusion Fabrication

Experimental Investigation of Effect of Environment Temperature on Freeze-form Extrusion Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/97b15405-0eb9-48d8-b63a-808e4cdd512e/download

null

['Wagner, Joshua J.', 'Shu, Hang', 'Kilambi, Rahul', 'Higgs, C. Fred III']

2021-11-16T16:02:13Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90325', 'http://dx.doi.org/10.26153/tsw/17246']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['fluid dynamic', 'particle dynamic', 'droplet impact', 'powder bed', 'binder jet 3D printing']

Experimental Investigation of Fluid-Particle Interaction in Binder Jet 3D Printing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b9922c8d-582a-4c78-94e1-d48dc19395b9/download

University of Texas at Austin

Wide-scale adoption of binder jet 3D printing for mission-critical components in aerospace, biomedical, defense, and energy applications requires improvement in mechanical properties and performance characteristics of end-use components. Increased fidelity may be achieved with better understanding of the interfacial physics and complex fluid-particle interactions fundamental to the process. In this work, an experimental testing apparatus and procedure is developed to investigate the fluid and particle dynamics occurring upon impact of jetted binder droplets onto a powder bed. High-speed, microscopic imaging is employed to capture short time-scale phenomena such as ballistic particle ejection, capillary flow, and particle clustering. The effects of different process parameters (e.g., translational printhead velocity, jetting frequency, and impact velocity) on the dynamics of Inconel powder are studied. These experiments reveal that the fluid-particle interaction is significantly affected by a combination of printing parameters, ultimately governing the quality and performance of binder jet 3D printed components.

null

['Kadekar, Vinay', 'Prakash, Sashikanth', 'Liou, Frank']

2020-02-12T16:10:07Z

2004

Mechanical Engineering

null

['https://hdl.handle.net/2152/79945', 'http://dx.doi.org/10.26153/tsw/6971']

eng

2004 International Solid Freeform Fabrication Symposium

Open

Laser Metal Deposition

Experimental Investigation of Laser Metal Deposition of Functionally Graded Copper and Steel

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1fbc743d-2ce5-4e3b-af01-bcb200d86072/download

null

Laser metal deposition is an emerging technology for producing fully dense metallic parts. This process shows a promising future for the deposition of functionally graded steel - copper alloys. Good thermal conductivity of copper and a high wear resistance of steel can be achieved in dies and cores. However, to accomplish this, there are many issues to be resolved, such as the formation of an undesirable phase, solidification cracking, porosity at the interface and difference in thermal coefficient of expansion between steel and copper. The influences of process variables, such as laser power, laser scan speed, composition, powder flow rate, on the success of the process, should be studied.

null

['Kruth, Jean-Pierre', 'Deckers, Jan', 'Yasa, Evren']

2020-03-11T15:40:48Z

9/10/08

Mechanical Engineering

null

['https://hdl.handle.net/2152/80256', 'http://dx.doi.org/10.26153/tsw/7275']

eng

2008 International Solid Freeform Fabrication Symposium

Open

Selective Laser Melting

Experimental Investigation of Laser Surface Remelting for the Improvement of Selective Laser Melting Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e85e10b2-116d-407d-9be4-e099cea43bf2/download

null

['Kao, Yi-Tang', 'Dressen, Trace', 'Kim, Dong Sung']

2021-10-21T15:05:12Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89388

eng

2015 International Solid Freeform Fabrication Symposium

Open

['3D printing', 'additive manufacturing', 'composite materials']

Experimental Investigation of Mechanical Properties of 3D-Printing Built Composite Material

Conference paper

https://repositories.lib.utexas.edu//bitstreams/afa10a57-fc20-446a-b2cc-2b5028d4f952/download

University of Texas at Austin

This paper studies the mechanical behaviors of a new composite material manufactured by 3D printing and polymer impregnation techniques. This composite uses 3D-printed plaster with an open-cellular structure as a frame to encapsulate the silicone resin (PDMS) to form a solid body. Because of the vastly different characteristics of the materials that make it up, the composite could have a wide variety of mechanical behaviors. In this study, design of experiment was performed with four-point bending tests using different composition ratios and sizes of open cells to determine the mechanical properties of the composite. These properties include maximum flexural stress (σmax), flexural secant modulus of elasticity (Ef), and toughness indices (I5 and I20). The experimental results show that both Ef and σmax are proportional to the plaster content and the unit cell size, while I20 had an opposite trend. The Ef ranged from 20 to 280 MPa, and σmax ranged from 0.3 to 1.2 MPa for a 25%-75% plaster content and 3.25-6.5 mm cell size. Statistical analysis further confirmed the differences between these cases. This paper has demonstrated the capability of this composite to exert different mechanical properties for functional applications.

null

['Ravi Kumar, Y.', 'Manmadhachary, A.', 'Krishnanand, L.']

2021-10-18T20:45:09Z

2014

Mechanical Engineering

null

https://hdl.handle.net/2152/89239

eng

2014 International Solid Freeform Fabrication Symposium

Open

['CT', 'dimensional error', 'volumetric error', 'rapid prototyping', 'CT image acquisition', 'ANOVA']

Experimental Investigation of Process Parameters on 64 Slice Spiral CT Scanner of Medical Models

Conference paper

https://repositories.lib.utexas.edu//bitstreams/13f28a33-421e-4026-9232-652520335b89/download

University of Texas at Austin

Rapid Prototyping (RP) is one of the advanced manufacturing methods to develop medical models. These models are generated by 3-Dimensional (3D) Computer Aided Design (CAD) model using Computed Tomography (CT) images. One of the advanced CT scanners to capture the large volume of tissues in shorter scan time is 64 slice spiral CT scanner. While developing these medical models, dimensional and volumetric errors occur due to Beam Hardening (BH) effect. This work has led to explore the influence of various CT Image acquisition parameters on the dimensional and volumetric errors, which are evaluated experimentally. A L9 orthogonal array and signal to noise ratio are applied to study performance characteristics of CT image acquisition parameters like tube voltage, tube current and pitch. The experimental results are analyzed by using the analysis of variance (ANOVA) method and significant factors are identified. In this work, it has been concluded that there is a reduction of dimensional error from 1.43 mm to 0.52 mm and volumetric error from 6793 mm3 to 3892 mm3.

null

['Czink, S.', 'Schulze, V.', 'Dietrich, S.']

2024-03-25T23:51:51Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124345', 'https://doi.org/10.26153/tsw/50953']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['PBF-LB', 'AlSi10Mg', 'additive manufacturing']

EXPERIMENTAL INVESTIGATIONS OF INHOMOGENEOUS COMPONENT PROPERTIES IN LASER-BASED ADDITIVE MANUFACTURING OF AlSi10Mg

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6609f58c-d7db-465a-a502-419f1ab97109/download

University of Texas at Austin

In the laser-based additive manufacturing (PBF-LB) process of AlSi10Mg components, the layer-by-layer deposition leads to microscopic and macroscopic thermal effects (shrinkage, residual stresses, overheating) depending on the component geometry. This results in a strong dependence of the microstructure and therefore of the process-induced material properties on the shape of the manufactured component. To analyze this behavior, components with different geometric aspects, such as various construction angles, were built using the PBF-LB process. In order to perform a spatially-resolved characterization and evaluation of the mechanical behavior of the component, small-scale tensile specimens in the sub-millimeter range were manufactured from representative areas of the components. With the obtained results, design approaches based on local material data can be improved significantly.

null

Liu, Jie

2021-09-30T15:43:00Z

2010

Mechanical Engineering

null

['https://hdl.handle.net/2152/88267', 'http://dx.doi.org/10.26153/tsw/15208']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['selective laser sintering', 'iron based alloy', 'nano-Al2O3 ceramic bulk materials']

Experimental Research on Fabrication of Iron Based Alloy and Nano-Al2O3 Powder Parts by Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/7d89907c-0e99-43d6-b8a0-362252b476c0/download

University of Texas at Austin

Experiments on selective laser sintering of Iron Based Alloy and nano-Al2O3 Ceramic Bulk Materials are carried out and effect of sintering parameters on the process is analyzed systematically. A reasonable selective laser sintering technique which can be used to fabricate parts wit h free shape is obtained and verified wit h a multilayer sintering experiment. The component and t he microstructure of t he sintering production is tested. The influences of parameters and the amount of nano-Al2O3 on microstructure and microhardness of the sintering parts are studied. Laser sintering iron-based alloy experiments show that: microhardness has been noticeably improved. It is indicated that with the selective laser sintering technique obtained above, nano-alumina can be processed to manufacture three-dimension parts with free shape. With the addition of Al2O3 and the increase of composite parts of the grain gradually thinning, microhardness gradually improved nanocomposite parts for the microstructure of the dendrite skeleton-shaped crystal and the plane together, the internal Al2O3 dispersion organizations to strengthen the implicit crystal martensite and ferrite mixed organizations.

null

['Sager, Benay', 'Rosen, David W.', 'Shilling, Meghan', 'Kurfess, Thomas R.']

2019-11-15T16:18:05Z

2003

Mechanical Engineering

null

['https://hdl.handle.net/2152/78420', 'http://dx.doi.org/10.26153/tsw/5507']

eng

2003 International Solid Freeform Fabrication Symposium

Open

Stererolithography

Experimental Studies in Stereolithography Resolution

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5af4e4b0-a42d-4e31-a88f-a584fc64dbc0/download

null

As we move towards micron-scale rapid manufacturing, it is critical to understand build resolution of Stereolithography technology. In order to determine the resolution limitations, positive and negative features on Stereolithography parts were built and analyzed. Results from several experiments were compared to an analytical model and important resolution issues are highlighted. Based on these experimental results, parameters that will maximize build resolution for a number of well-understood shapes are suggested in the paper. Build resolution experimental results, analysis, and measurement techniques are discussed. Conclusions are drawn related to feature shape as resolution limits are approached.

We gratefully acknowledge the support from the RPMI member companies and the George W. Woodruff School of Mechanical Engineering at Georgia Tech. This work was partially funded by the National Science Foundation under Grant Number DMI-9988664.

null

['Paul, Sumit', 'Yang, Li']

2023-03-01T17:27:29Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117552', 'http://dx.doi.org/10.26153/tsw/44432']

eng

2022 International Solid Freeform Fabrication Symposium

Open

Additive manufacturing

An Experimental Study of Cellular Mechanical Interface in a Bi-Material Structure Fabricated by Material Extrusion Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/03801607-228a-4de6-8a84-0707e2fcf1ba/download

null

This work is a continuation of the preliminary project with the investigation of the characteristics of the cellular structure-based mechanical interlocking interface designs for bi-material structures fabricated by material extrusion additive manufacturing (AM). Three different cellular designs, including auxetic, body centered cubic (BCC), and octahedral, were investigated for the topology design effects on the interface performance. In addition, the effects of build orientation and interface polarity were also studied. The results clearly suggested that the cellular-based mechanical interlocking interface exhibit significantly enhanced ductility and energy absorption that can be desirable to many applications, and that the interface characteristics are influenced by both the topology design of the cellular structures and the intrinsic properties of the processed materials.

null

['Zhang, Shanshan', 'Miyanaji, Hadi', 'Yang, Li', 'Zandinejad, Amir Ali', 'Dilip, J.J.S.', 'Stucker, Brent']

2021-10-18T20:52:25Z

2014

Mechanical Engineering

null

https://hdl.handle.net/2152/89242

eng

2014 International Solid Freeform Fabrication Symposium

Open

['3D printing', 'dental porcelain', 'dental restorations']

An Experimental Study of Ceramic Dental Porcelain Materials Using a 3D Print (3DP) Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/90360de4-d948-4290-b346-c1b1223063ff/download

University of Texas at Austin

Dental porcelain materials have been used widely in dental restorations such as crowns, veneers and onlays. In this study, a commercial dental-grade porcelain powder (IPS InLine Dentin) was investigated for compatibility with 3D printing. An extensive experimental study was carried out to evaluate the effects of various in-process and post-process parameters on the geometrical accuracies and porosities of the dental porcelain structures, and optimal process parameters were determined that result in homogeneous shrinkage and minimized part distortions. This study established a practical guideline for the direct fabrication of dental porcelain structures, which enabled further development of this material that focused on performance improvement.

null

['Ramirez Chavez, Irving E.', 'Noe, Cameron', 'Sekar, Vigneshwaran', 'Jogani, Shainil', 'Israni, Siddharth', 'Bhate, Dhruv']

2021-11-30T19:47:37Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90526', 'http://dx.doi.org/10.26153/tsw/17445']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['design for additive manufacturing', 'stiffener', 'compression', 'plate', 'shell', 'topology optimization']

An Experimental Study of Design Strategies for Stiffening Thin Plates under Compression

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2ccd6943-2acb-4dfb-91e0-328e6d18b65e/download

University of Texas at Austin

Increasing stiffness and failure loads while minimizing mass is useful in many engineering applications, including the design of thin plates and shells. In this paper, the performance of thin plates using a range of stiffening approaches were studied for the specific instance of compressive loading. Periodic, graded, stepped, “Voronoi” stochastic, and topologically optimized patterns were explored. These stiffening designs were realized using different software tools and manufactured with the Selective Laser Sintering (SLS) process. These 3D printed specimens were tested under compression to assess their mechanical response. Videos of these tests were recorded to study the shape of the failure modes. This data was analyzed to determine the performance of the different stiffener designs, in comparison to the performance of baseline plates without any stiffening. The study concludes with a discussion of the results and their implications for stiffening thin plates, showing that triangular and stochastic stiffening strategies show particular promise in increasing specific compressive stiffness and specific buckling load.

null

['Guo, Nannan', 'Leu, Ming C.']

2021-10-05T18:48:46Z

8/16/12

Mechanical Engineering

null

['https://hdl.handle.net/2152/88405', 'http://dx.doi.org/10.26153/tsw/15344']

eng

2012 International Solid Freeform Fabrication Symposium

Open

['Selective Laser Sintering', 'Polymer Electrolyte Membrane', 'fuel cells', 'graphite composite bipolar plates', 'flow fields']

Experimental Study of Polymer Electrolyte Membrane Fuel Cells using a Graphite Composite Bipolar Plate Fabricated by Selective Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a9e76ed2-13f6-41b9-94b2-bfab0c2b6652/download

University of Texas at Austin

Selective Laser Sintering (SLS) can be used to fabricate graphite composite bipolar plates with complex flow fields for Polymer Electrolyte Membrane (PEM) fuel cells. The additive manufacturing process can significantly reduce the time and cost associated with the research and development of bipolar plates as compared to other fabrication methods such as compression molding. In this study, bipolar plates with three different designs, i.e., parallel in series, interdigitated, and bio-inspired, were fabricated using the SLS process. The performance of these SLS-fabricated bipolar plates was studied experimentally within a fuel cell assembly under various operating conditions. The effect of temperature, relative humidity, and pressure on fuel cell performance was investigated. In the tests conducted for this study, the best fuel cell performance was achieved with a temperature of 75℃, relative humidity of 100%, and back pressure of 2 atm.

null

['Rajan, Jagan R.', 'Wood, Kristin L.', 'Malkovich, Nick']

2019-10-18T14:45:21Z

2001

Mechanical Engineering

null

['https://hdl.handle.net/2152/76227', 'http://dx.doi.org/10.26153/tsw/3316']

eng

2001 International Solid Freeform Fabrication Symposium

Open

Sintering

Experimental Study of Selective Laser Sintering of Parmax

Conference paper

https://repositories.lib.utexas.edu//bitstreams/03938250-f7c0-4629-9872-c090dffeb04c/download

null

Selective Laser Sintering (SLS) has been used to successfully process crystalline polymers, ceramics and metals. However, wide range of materials available and their applications have acted as an impetus to expand the applications of SLS to different material systems. This paper presents one such experimental study undertaken to explore the application of SLS to process Parmax® polymers – a family of high performance amorphous poly pphenylenes. As a part of the collaborative study, various process parameters and material formulations were tried out to ascertain the feasibility of the process and the initial results obtained look promising. This paper lists the material formulations tested and process parameters controlled. Also, analysis of the results of the experimental study and the outline of the next phase of research to be undertaken have been described. This study was motivated by the numerous applications of Parmax® in the electronics, defense and aerospace industries as well as the goal to expand the applications and utility of SLS.

null

['Torossian, Kevin', 'Bourell, David']

2021-10-21T22:09:04Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89458

eng

2015 International Solid Freeform Fabrication Symposium

Open

['snap-fits', 'additive manufacturing', 'mating force', 'dismounting force', 'geometrical parameters']

Experimental Study of Snap-Fits Using Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9a2b5f40-e657-4b34-86ba-17070c3cadbf/download

University of Texas at Austin

A snap-fit is a mechanical joint system whose mating parts exert a cam action, flexing until one part slips past a raised lip on the other part, preventing their separation. The use of snaps in additive manufacturing (AM) is an approach for assembling components of parts too large to build in one piece in AM. There are broadly two types of snap-fits possible to encounter, permanent and non-permanent, depending on the design geometry. An experimental study was carried out to evaluate the mating/dismounting force for snap-fits regarding several geometrical parameters for additive manufacturing. The design chosen for this study has been established from the start to work on only one design. The parameters chosen for experimental investigation were the mating angle, the separation angle and the inner diameter of the mating part. All in all, fifteen pairs were designed and additive manufactured for evaluation. The force required to insert and separate the snap components was recorded and compared to the value based on a derived equation.

null

['Sun, Q.', 'Rizvi, G.M.', 'Bellehumeur, C.T.', 'Gu, P.']

2019-11-20T16:46:17Z

2003

Mechanical Engineering

null

['https://hdl.handle.net/2152/78481', 'http://dx.doi.org/10.26153/tsw/5566']

eng

2003 International Solid Freeform Fabrication Symposium

Open

Polymer Filaments

Experimental Study of the Cooling Characteristics of Polymer Filaments in FDM and Impact on the Mesostructures and Properties of Prototypes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/69809e49-4f1c-4520-8bbb-1f311c043ee5/download

null

The bonding quality among polymer filaments in the fused deposition modeling (FDM) process determines the integrity and mechanical properties of the resultant prototypes. This research investigates the bond formation among extruded acrylonitrile butadiene styrene (ABS) filaments in the FDM process. Experimental measurements of the temperature profiles were carried out for different specimens and their effects on mesostructures and mechanical properties were observed. Models describing the formation of bonds among polymer filaments during the FDM process are discussed. Predictions of the degree of bonding achieved during the filament deposition process were made based on thermal analysis of extruded polymer filaments. The bond quality was assessed based on the growth of the neck formed between adjacent filaments and their failure under flexural loading. Further experimental work is underway to assess the validity of the proposed models.

The financial support for this work was provided by the Natural Sciences and Engineering Research Council of Canada (NSERC) through Research Grants awarded to Drs. Bellehumeur and Gu.

null

['Horton, Leslie', 'Gargiulo, Edward']

2018-05-03T18:39:02Z

1993

Mechanical Engineering

doi:10.15781/T2K35MX4R

http://hdl.handle.net/2152/65056

eng

1993 International Solid Freeform Fabrication Symposium

Open

['stereolithography', 'rapid prototyping', 'TRIHATCH']

An Experimental Study of the Parameters Affecting Curl in Parts Created Using Stereolithography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d8c6706e-ebf0-4d35-9225-8f89e637b96b/download

null

['Lakshminarayan, Uday', 'Marcus, H.L.']

2018-04-19T16:01:43Z

1992

Mechanical Engineering

doi:10.15781/T27H1F42X

http://hdl.handle.net/2152/64376

eng

1992 International Solid Freeform Fabrication Symposium

Open

['Center for Materials Science and Engineering', 'CAD', 'laser sintering', 'SLS']

An Experimental Study of the Relationship between Microstructure and Mechanical Properties of a Ceramic Composite Fabricated by Selective Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/60800070-ce6f-4520-af76-ea8a83c1bfdf/download

null

Alumina-ammonium phosphate powder blends were processed with Selective Laser Sintering. Ammoniumphosphate with a melting point of 190°C, acts as a binder when processed with a laser and holds the alumina (m.p. 2300°C) particles together to form a "green" body. When the green body is heat treated at 850°C for 6 hours, ammonium phosphate decomposes evolving ammonia and water vapor. Residual P205 reacts with alumina to form aluminum phosphate. This results in a composite of unreacted alumina with a coating of aluminum phosphate around the alumina particles. The variation of compressive strength of these low density ceramic composites was investigated in terms of the particle size distribution the amount of binder in the initial blend. It was observed that the strength depends on the relative density and initial blend composition and the critical flaw size. A constitutive equation was formulated to characterize the influence of the relative density, binder composition and the critical flaw size on the strength of the composite.

null

['Valenti, Justin D.', 'Bartolai, Joseph', 'Yukish, Michael A.']

2023-02-09T18:58:38Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117441', 'http://dx.doi.org/10.26153/tsw/44322']

eng

2022 International Solid Freeform Fabrication Symposium

Open

wing structure

Experimental Study of Wing Structure Geometry to Mitigate Process-Induced Deformation

Conference paper

https://repositories.lib.utexas.edu//bitstreams/19a52146-2128-45d8-8fa5-937a0aff8ff5/download

null

Small uncrewed aerial vehicles that are fabricated with material extrusion additive manu- facturing often have wings that are single-perimeter structures with sparse internal structure. The large distance between internal supports creates an “unsupported-wall distance”, which leaves the wing skin prone to deformation during fabrication. This work explores and quan- tifies the relationship between the deformation of the wing skin and three geometric param- eters: (1) unsupported-wall distance, (2) local surface curvature, and (3) extrusion width. A three-level full factorial study was devised in which wing sections of varying surface curva- ture, unsupported-wall distance, and extrusion width were fabricated with polymer material extrusion additive manufacturing. The surfaces of the wing sections were then digitized into point clouds with a coordinate measuring machine, and the point cloud data were directly compared to the GCode used to print each wing section. The deformation data was analyzed to quantify the relationship between deformation and the experimental parameters. From the experiment, a non-dimensional term was identified that captures a bounding relationship between the geometric parameters and the deformation. Finally, a mathematical expression was developed to serve an upper bound on unsupported-wall distance based on extrusion width and surface curvature.

null

['Price, Steven', 'Lydon, James', 'Cooper, Ken', 'Chou, Kevin']

2021-10-07T15:55:04Z

8/16/13

Mechanical Engineering

null

['https://hdl.handle.net/2152/88488', 'http://dx.doi.org/10.26153/tsw/15422']

eng

2013 International Solid Freeform Fabrication Symposium

Open

['electron beam additive manufacturing', 'powder-based', 'infrared thermal imager', 'temperature measurements']

Experimental Temperature Analysis of Powder-Based Electron Beam Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/bb1898dd-ac2c-4021-9973-bf3dd811b9b2/download

University of Texas at Austin

A near infrared thermal imager has been employed for temperature measurements (build part surfaces) in the powder-based electron beam additive manufacturing (EBAM) process. A methodology has also been developed to analyze temperature distributions and history around the melting scan area. The temperature profiles along the beam scanning clearly show the moving source of heat phenomenon, with the peak temperature reaching over 2000 °C (for Ti6Al-4V) followed by extremely rapid cooling opposite to the beam scanning direction, except a slow-cooling portion corresponding to the liquidus-solidus range. The build surface temperatures and the melt pool sizes, in the localized electron beam scanning area, were studied at various configurations, e.g., different build heights, also with or without an overhang.

null

['Masoomi, M.', 'Thompson, S.M.', 'Shamsaei, N.', 'Elwany, A.', 'Bian, L.']

2021-10-19T18:54:12Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89323

eng

2014 International Solid Freeform Fabrication Symposium

Open

['Selective Laser Melting', 'powder bed', 'heat transfer', 'stainless steel']

An Experimental-Numerical Investigation of Heat Transfer During Selective Laser Melting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/cd7366fe-4a0c-4a73-add8-f92b06658a66/download

University of Texas at Austin

The heat transfer in and around a part being fabricated via Selective Laser Melting (SLM) is numerically simulated while considering the surrounding powder bed modeled to have an effective thermal conductivity. By accurately simulating the powder bed heat transfer during SLM, mechanical properties of parts can be better predicted. Heat transfer to previously-deposited layers and the build plate are also simulated. In order to validate the presented model, a thermocouple was embedded into a substrate used and a SLM system was utilized for performing two experiments. In the first set, various laser power and scan speed combinations were employed while passing the laser over the thermocouple-embedded substrate. This procedure calibrated the numerical model and demonstrated that the heat transfer due to convection and radiation during deposition of a single layer is approximately 10-15% of initial laser power input. The final experiment consisted of building a thin wall of SLM of 17-4 PH stainless steel (SS). The effects of scan pattern and part size on the temperature response of and around the part are demonstrated as significant. Distinct heating and cooling rates are also provided for these various cases; indicating the dependency of final microstructure on part size and the utilized scan pattern.

null

['Cormier, Denis', 'Taylor, James', 'Unnanon, Kittnan', 'Kulkarni, Parikshit', 'West, Harvey']

2019-09-23T16:01:45Z

2000

Mechanical Engineering

null

['https://hdl.handle.net/2152/75948', 'http://dx.doi.org/10.26153/tsw/3047']

eng

2000 International Solid Freeform Fabrication Symposium

Open

Electro-Photographic

Experiments In Layered Electro-Photographic Printing 267

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b9a97942-c581-43ef-afb2-f0f6b03c1114/download

null

Electro-photographic printing processes employed by products such as laser printers and photocopiers are commonly used to deposit and fuse thin layers of thermoplastic powder onto paper. This report describes preliminary experiments aimed at adapting the electro-photographic printing process for use as a layered manufacturing technique. 3-D electro-photographic printing holds considerable potential as an inexpensive freeform fabrication technique that is suitable for office environments. The possibilities for selective coloring are also discussed.

null

['Hoelzle, David', 'Peng, Hao', 'Ghasri-Khouzani, Morteza', 'Gong, Shan', 'Attardo, Ross', 'Ostiguy, Pierre', 'Aboud Gatrell, Bernice', 'Budzinski, Joseph', 'Tomonto, Charles', 'Neidig, Joel', 'Shankar, M. Ravi', 'Billo, Richard', 'Go, David B.']

2021-11-04T14:00:10Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89962

eng

2017 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'DMLS', 'optimization', 'build orientation', 'support structure', 'heuristic learning', 'expert survey']

Expert Survey to Understand and Optimize Part Orientation in Direct Metal Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a9c41a6b-1779-4657-963c-ab5bc5551a4c/download

University of Texas at Austin

The additive manufacturing (AM) process Direct Metal Laser Sintering (DMLS) uses a layer-by-layer workflow to build complex architecture metal structures in low-volumes. The primary process failure mechanism is a thermal stress driven thermal distortion that yields out-of-tolerance manufacture or complete process failure. However, DMLS design experts have developed heuristic rules to optimize the part orientation and support structure to reduce the likelihood of failure. We believe that experts innately attempt to minimize the design metrics of support volume (V), support-to-part surface area (A), maximal cross-sectional area of the slicing planes (X), parallelism of part faces with the recoater blade (P), and part height (H); however, it is unclear what relative weighting of each metric the expert uses. This manuscript details an interactive expert survey, the statistical analysis of the survey responses, and the synthesis of an automatic algorithm for part orientation based on survey data. We received responses from 18 experts and 151 total part orientation responses. The median survey respondent had greater than four years of DMLS experience. Our analysis shows that the expert attempts to minimize metric V the most, metric X the second most, and metric H the third most; experts put essentially no weight on metrics A and P. The manuscript concludes with two orientation design studies where the expert survey responses are used in a least squares minimization algorithm to automatically orient the part for DMLS manufacture. As a comparison set, novice users were instructed to orient the parts for best DMLS printing success without using the tool and required multiple attempts to successfully print the test parts. The automatically oriented parts failed on our first iteration of the code. The manuscript concludes with our proposed modifications to the code to improve results.

null

['Watts, D. M.', 'Hague, R. J.']

2020-03-05T19:47:49Z

2006

Mechanical Engineering

null

['https://hdl.handle.net/2152/80149', 'http://dx.doi.org/10.26153/tsw/7170']

eng

2006 International Solid Freeform Fabrication Symposium

Open

Rapid Manufacturing

Exploiting the Design Freedom of RM

Conference paper

https://repositories.lib.utexas.edu//bitstreams/bd0bc482-3f86-4789-bc10-cb41ac68c164/download

null

This paper details how Rapid Manufacturing (RM) can overcome the restrictions imposed by the inherent process limitations of conventional manufacturing techniques and become the enabling technology in fabricating optimal products. A new design methodology capable of exploiting RM’s increased design freedom is therefore needed. Inspired by natural world structures of trees and bones, a multi-objective, genetic algorithm based topology optimisation approach is presented. This combines multiple unit cell structures and varying volume fractions to create a heterogeneous part structure which exhibits a uniform stress distribution.

null

['Heineman, Jesse J.', 'Lind, Randall F.', 'Chesser, Phillip C.', 'Post, Brian K.', 'Boulger, Alex M.', 'Roschli, Alex', 'Love, Lonnie J.', 'Gaul, Katherine T.']

2021-11-30T19:34:16Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90523', 'http://dx.doi.org/10.26153/tsw/17442']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['SKYBAAM', 'additive manufacturing', 'cable-driven', '3D printing', 'tower structures']

Exploration of a Cable-Driven 3D Printer for Concrete Tower Structures

Conference paper

https://repositories.lib.utexas.edu//bitstreams/334cfb01-708a-4740-9c56-e5a6fed1ea2a/download

University of Texas at Austin

Researchers at Oak Ridge National Laboratory’s Manufacturing Research Demonstration Facility (MDF) are currently developing a cable-driven concrete additive manufacturing (AM) system called SKYBAAM. This system is a novel solution for 3D printing large structures using concrete. The current research focuses primarily on proof of concepts for the cable driven system, material selection, material pumping solutions, and the concrete extruder design. Looking forward from the success of the current research, this paper investigates the feasibility of using the SKYBAAM on a larger scale, specifically for extremely tall tower structures. The current system design presents challenges at a larger scale, and so the primary focus of this paper is to investigate new designs of a platform that would support large-scale SKYBAAM operations. Additionally, this paper will discuss the resulting deflections that can be expected due to machine operation and wind-loading. Excessive structural deflections could lead to loss of printing accuracy, or even a complete failure of the print, so it is important to establish that acceptable deflections can be reasonably achieved on these large-scale tower structures.

null

['Bai, Yun', 'Williams, Christopher B.']

2021-10-13T21:39:17Z

2014

Mechanical Engineering

null

['https://hdl.handle.net/2152/88789', 'http://dx.doi.org/10.26153/tsw/15723']

eng

2014 International Solid Freeform Fabrication Symposium

Open

['high purity copper', 'copper', 'binder jetting', 'additive manufacturing', 'green parts']

An Exploration of Binder Jetting of Copper

Conference paper

https://repositories.lib.utexas.edu//bitstreams/791d58b7-439f-4f7c-8b8c-4c75b272ee22/download

University of Texas at Austin

The ability to fabricate geometrically complex copper shapes via Additive Manufacturing (AM) could have a significant impact on the design and performance of thermal management systems and structural electronics. In this research a Binder Jetting AM process (ExOne R2) was used to fabricate green parts made of high purity copper powder. Once printed, the green part was sintered under a reducing atmosphere to create copper parts in pure metal form. The authors varied (i) powder size, (ii) sintering profiles, and (iii) atmospheric control to explore their effects on final part density and shrinkage. The sintered part density was 85% of the theoretical value due to the relatively coarse powder and loose packing of the powder bed. The result demonstrates the feasibility of using Binder Jetting to create copper parts with complex geometries.

null

['Li, Wei', 'Bouzolin, Dan', 'Nagaraja, Kishore Mysore']

2024-03-26T23:10:22Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124443', 'https://doi.org/10.26153/tsw/51051']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['wire arc additive manufacturing', 'thermal-fluid model', 'in-space manufacturing', 'reduced gravity', 'space exploration']

EXPLORATORY STUDY OF IN-SPACE WIRE ARC ADDITIVE MANUFACTURING WITH MODELING APPROACH

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8e696264-8386-4a42-ab38-73ee120b2479/download

University of Texas at Austin

Countries all over the world are rushing into space exploration due to crisis of energy and resources exhaustion on the Earth. Mars is an obvious target because it has a thin atmosphere, good geological similarity, and is close by in the Solar system. As the satellite of the Earth, Moon is another target since it is very close to the Earth. For the large spacecrafts such as Mars rovers, periodic maintenance is necessary to ensure the completion of long-duration exploration missions. In-space wire arc additive manufacturing (WAAM) provides a potential solution towards sustainable maintenance with onsite repair or additive manufacturing. For in-space manufacturing, reduced gravity is an important factor. In this work, WAAM processes under reduced gravity conditions on the Mars and Moon were studied through a multi-physics modeling approach. The metal droplet transfer, deposition geometry, thermal dissipation, and other key physics in WAAM were simulated. To validate the modeling approach, an experimental case was conducted on an in-house WAAM platform under the Earth condition.

null

['Roach, M.A.', 'Pennney, J.', 'Jared, B.H.']

2024-03-26T20:49:18Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124406', 'https://doi.org/10.26153/tsw/51014']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['ROS2', 'IOT sensors', 'additive manufacturing']

EXPLORING A SUPERVISORY CONTROL SYSTEM USING ROS2 AND IOT SENSORS

Conference paper

https://repositories.lib.utexas.edu//bitstreams/eebab146-eeef-4571-a651-2669ffa3200c/download

University of Texas at Austin

Whether collecting data from process monitoring sensors or controlling a system of multiple actuators and electrical systems, a powerful supervisory control system must be developed for additive manufacturing (AM) systems. The Robot Operating System version 2 (ROS2) is a set of software libraries that can be used to control robotics systems and has tools for sensor value publishing. This research project is exploring the use of computational nodes connected to process monitoring sensors and robotic or electrical systems to allow for a more in-depth knowledge of the system health and process as well as open the possibilities of process control. These nodes can be connected and controlled by the ROS2 architecture. Work will be discussed exploring the reliability and speed of common AM processes and sensors such as robot controllers and thermal monitoring.

null

['Nabil, S.T.', 'Banuelos, C.', 'Ramirez, B.', 'Cruz, A.', 'Watanabe, K.I.', 'Arrieta, E.', 'Wicker, R.B.', 'Medina, F.']

2024-03-25T23:54:26Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124346', 'https://doi.org/10.26153/tsw/50954']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['E-PBF', 'scanning strategies', 'superalloys', 'Inconel 718']

EXPLORING IN718 ALLOY PRODUCTION WITH BI-DIRECTIONAL RASTER AND STOCHASTIC SPOT MELTING TECHNIQUES USING AN OPEN-SOURCE ELECTRON MELTING SYSTEM

Conference paper

https://repositories.lib.utexas.edu//bitstreams/07b22f79-08d2-4399-b74f-2c5d216250ac/download

University of Texas at Austin

This study compares the fabrication of IN718 alloy using bi-directional raster and stochastic spot melting techniques with the open-source FreemeltOne Electron Beam Melting (EBM) system. The research aimed to produce dense parts using both scanning strategies, employing custom Python code for raster melt beam path generation and PixelMelt software for stochastic spot melting path generation. After optimizing process parameters, 10mm height builds for each scanning strategy were fabricated, and their microstructure, hardness, and density were analyzed using optical microscopy and SEM, Vickers microhardness scale, and a pycnometer. The findings reveal valuable insights into the effects of scanning strategies on the microstructure, hardness, and density of IN718 alloy components, advancing additive manufacturing knowledge.

null

['Lipman, Robert R.', 'McFarlane, Jeremy S.']

2021-10-19T20:47:46Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89336

eng

2015 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'part geometry', 'tolerances', 'model-based engineering']

Exploring Model-Based Engineering Concepts for Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8d8bcb02-2da8-4033-a460-ac8e4adad019/download

University of Texas at Austin

Robust geometry and tolerance representations are needed in additive manufacturing for precise part specification and interoperability with downstream activities such as manufacturing, inspection, and long-term archiving. A disconnection exists between process-independent part geometry and tolerances, and process-dependent information requirements for additive manufacturing. Existing and emerging standards for part geometry (ASTM AMF, 3MF, ISO 10303 STEP) and tolerances (ASME Y14) contain information related to the additive manufacturing process. Details of the standards will be discussed, how their use and improvement can benefit the additive manufacturing process, and their integration into the model-based engineering paradigm.

null

['Gao, Harry', 'Meisel, Nicholas A.']

2021-11-04T14:24:54Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89969

eng

2017 International Solid Freeform Fabrication Symposium

Open

['conductive filament', 'manufacturability', 'resisitivty', 'material extrusion', 'additive manufacturing']

Exploring the Manufacturability and Resistivity of Conductive Filament Used in Material Extrusion Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/481db5bf-a3a6-4787-985a-0036e5657a8a/download

University of Texas at Austin

Additive manufacturing (AM) has the unique ability to build multifunctional parts with embedded electronics without the need for post-print assembly. However, many existing forms of multifunctional AM are not easily accessible to hobby-level users. Most hobby-level desktop 3D printers are only used with non-conductive filaments. Recently however, conductive filaments have become increasingly available for material extrusion desktop printers. Ideally, the use of these filaments would allow circuitry to be printed simultaneously with the rest of the structure, enabling complex, inexpensive, multifunctional structures. However, the resistivity of conductive filament is significantly impacted by the geometry of the print and the printing parameters used in the build process. In this study, two types of commercially-available conductive filament were tested under a variety of parameters. It was found that print temperature, layer height, and orientation all significantly affect the resistivity in various ways. The knowledge from this research will allow users to design better multifunctional parts that have reduced resistivity.

null

['Li, J.', 'Monaghan, T.', 'Bournias-Varotsis, A.', 'Masurtschak, S.', 'Friel, R.J.', 'Harris, R.A.']

2021-10-18T20:15:06Z

2014

Mechanical Engineering

null

https://hdl.handle.net/2152/89229

eng

2014 International Solid Freeform Fabrication Symposium

Open

['Ultrasonic Additive Manufacturing', 'electronic materials', 'dielectric materials', 'metal matrices']

Exploring the Mechanical Performance and Material Structures of Integrated Electrical Circuits within Solid State Metal Additive Manufacturing Matrices

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9be0905b-a90f-4c75-b53a-ed0bd9e51730/download

University of Texas at Austin

Ultrasonic Additive Manufacturing (UAM) enables the integration of a wide variety of components into solid metal matrices due to a high degree of metal plastic flow at low matrix bulk temperatures. This phenomenon allows the fabrication of previously unobtainable novel engineered metal matrix components. The aim of this paper was to investigate the compatibility of electronic materials with UAM, thus exploring an entirely new realm of multifunctional components by integration of electrical structures within dense metal components processed in the solid-state. Three different dielectric materials were successfully embedded into UAM fabricated metal-matrices with, research derived, optimal processing parameters. The effect of dielectric material hardness on the final metal matrix mechanical strength after UAM processing was investigated systematically via mechanical peel testing and microscopy. The research resulted in a quantification of the role of material hardness on final UAM sample mechanical performance, which is of great interest for future industrial applications.

null

['Denoual, M.', 'Mognol, P.', 'Lepioufle, B.']

2020-02-13T20:50:16Z

8/25/04

Mechanical Engineering

null

['https://hdl.handle.net/2152/79976', 'http://dx.doi.org/10.26153/tsw/7001']

eng

2004 International Solid Freeform Fabrication Symposium

Open

biochips

Exploring Vacuum Casting Techniques for Micron and Submicron Features

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e73ba7dd-9bae-4cc0-a2ba-9ad830dcddaf/download

null

A study of resolution limits in standard rapid prototyping vacuum cast molding processes and adaptation of this technique to reach submicron accuracy is proposed. Micro-fabrication technologies are used to fabricate micron and submicron high aspect-ratio patterns on the original parts. The molding of the original parts is optimized to allow replication of submicron features. In carefully exploring materials and surface treatments, cast parts are successfully replicated with submicron and high aspect ratio micron structures. These encouraging results enable the use of such processes for micro- and nano-systems applications and open the door to development and production of low cost, high resolution biochips.

null

['Bass, Lindsey B.', 'Meisel, Nicholas A.', 'Williams, Christopher B.']

2021-10-21T15:25:30Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89395

eng

2015 International Solid Freeform Fabrication Symposium

Open

['material jetting', 'multi-material', 'build orientation', 'variability']

Exploring Variability in Material Properties of Multi-Material Jetting Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/13ee23e7-31de-4fb6-ad55-698782caa151/download

University of Texas at Austin

With Additive Manufacturing (AM) capabilities rapidly expanding in industrial applications, there exists a need to quantify materials' mechanical properties to ensure reliable performance that is robust to variations in environment and build orientation. While prior research has examined process-parameter and environmental effects for AM processes such as extrusion, vat photopolymerization, and powder bed fusion, existing similar research on the material jetting process is limited. Focusing on polypropylene-like (VeroWhitePlus) and elastomer-like (TangoBlackPlus) materials, the authors first characterize the anisotropic properties of six different gradients produced from mixing the two materials in preset quantities. Three build orientations were used to fabricate parts and analyze tensile stress, modulus of elasticity, and elongation at break for each material. The authors also present results from an investigation of how aging of parts in different lighting conditions affects material properties. The results from these experiments provide an enhanced understanding of the material behaviors relating to material jetting process parameters and can inform material selection when manufacturing loadbearing parts.

null

['Choong, Y.Y.C.', 'Saeed, M.', 'Eng, H.', 'Su, P.-C.', 'Wei, J.']

2021-10-28T22:13:13Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89715

eng

2016 International Solid Freeform Fabrication Symposium

Open

['shape memory polymers', 'process parameters', '3D printing', 'stereolithography']

Exploring Variability in Shape Memory Properties of Stereolithography Printed Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f3750af9-dbe9-4480-80bf-cc898f49e25a/download

University of Texas at Austin

Shape memory polymers (SMPs) are smart materials that can change shape and revert to their permanent shape upon external stimulus. Most fabrications of SMPs are based on conventional methods which limit design freedom, hence additive manufacturing presents an alternative to expanding more possibilities for applications. In this study, curing process parameters were optimized for printing of photopolymerized thermoset SMPs by the stereolithography process. Tert-butyl acrylate (tBA) and di (ethylene glycol) diacrylate (DEGDA) were copolymerized with variations in crosslinkers to create networks with well-separated transition temperatures (Tg) that varied in a range from 43.6 to 74.1°C. A fold-deployable shape memory test was performed and revealed that free-strain recovery and retention deteriorate with increasing Tg. Nevertheless, the SMPs can undergo at least 20 repeated fold-deploy cycles before failure. These results are intended to provide better understandings in processing SMPs via stereolithography, while exploring variability in Tg widens the range of possible applications.

null

['Lipton, Jeffrey I.', 'Gluck, Karl', 'Lipson, Hod']

2021-09-30T20:07:46Z

9/23/10

Mechanical Engineering

null

['https://hdl.handle.net/2152/88292', 'http://dx.doi.org/10.26153/tsw/15233']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'Extensible Digital Fabrication Language', 'XDFL', 'ToolScript', 'system architecture', 'Fab@Home', 'geometric data', 'control processes']

Extensible Digital Fabrication Language for Digital Fabrication Processes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/29271574-8233-46b1-af30-0183f06fce1e/download

University of Texas at Austin

While additive manufacturing objects are described by the STL and AMF standards, the protocol controlling the fabricator is typically machine-specific. In this paper, we explore a system architecture that converts geometric data into control processes for equipment. We propose a new Extensible Digital Fabrication Language (XDFL) and an interpreted ToolScript language that describes how a geometry is translated into machine commands. An initial implementation of this system architecture was created and deployed as part of the Fab@Home project. The introduction of a standard process control language will decouple process planning from the equipment manufacturer, thereby catalyzing the introduction of new equipment and development of better process planners.

null

['Rai, Rahul', 'Campbell, Matthew', 'Wood, Kristin']

2020-02-13T21:00:19Z

2004

Mechanical Engineering

null

['https://hdl.handle.net/2152/79978', 'http://dx.doi.org/10.26153/tsw/7003']

eng

2004 International Solid Freeform Fabrication Symposium

Open

Solid freeform fabrication

Extracting Product Performance by Embedding Sensors in SFF Prototypes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/ab55e320-c4ca-4908-b81b-995a657d9ed6/download

null

SFF has been instrumental in improving the design process by providing designers with prototypes that assist them in the communication of design information and design visualization prior to creating fully functional prototypes. Embedding sensors at key locations within an SFF part to extract further data and monitor parameters at critical locations not accessible to ordinary sensors can help immensely in building functional SFF parts. However, this approach requires data acquisition of information such as temperature and strain values from interiors of products. In this work, the authors propose new techniques for embedding thermal sensors and strain gauges into fully dense DuraForm™ during Selective Laser Sintering (SLS) process. The embedded sensors have been used to measure temperatures and strains. They provide higher sensitivity, good accuracy, and high temperature capacity.

null

['Turner, Irem Y.', 'Wood, Kristin L.', 'Busch-Vishniac, Ilene J.']

2018-11-16T16:16:37Z

1996

Mechanical Engineering

doi:10.15781/T2DZ03M93

http://hdl.handle.net/2152/70293

eng

1996 International Solid Freeform Fabrication Symposium

Open

['surface quality', 'manufacturing', 'SLS machines']

Extraction of Fault Patterns on SLS Part Surfaces Using the Karhunen-Loeve Transform

Conference paper

https://repositories.lib.utexas.edu//bitstreams/fa9e719b-19d2-430b-8f9c-ca0e11ef1fc6/download

null

To gain a thorough understanding of the fault mechanisms in SLS machines, we decompose SLS profile signals into independent features using a novel tool called Karhunen-Loeve (KL) transform. These individual features can then be studied separately to monitor the occurrence of fault patterns on manufactured parts and determine their nature. Analytical signals with known fault patterns, simulating profile measurement signals from SLS parts, are used to determine the suitability of the proposed method. Multi-component patterns are assumed to manifest on SLS part surfaces, resulting from faults in the machine, for example, the roller mechanism. The results of this work determine the suitability of the KL transform for condition monitoring and extraction of fault-indicating patterns.

null

['Khoshnevis, Behrokh', 'Zhang, Jing']

2021-10-05T18:57:55Z

8/15/12

Mechanical Engineering

null

['https://hdl.handle.net/2152/88408', 'http://dx.doi.org/10.26153/tsw/15347']

eng

2012 International Solid Freeform Fabrication Symposium

Open

['Contour Crafting', 'sulfur concrete', 'lunar regolith']

Extraterrestrial Construction Using Contour Crafting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/496f36f8-06e8-4468-b8ae-72e0fe9da2e4/download

University of Texas at Austin

Most proposals for construction of settlements on Moon and Mars are based on transporting structural elements from Earth and assembling them at the destination. A far less expensive and potentially practical approach is using Contour Crafting, a large-scale AM process, in conjunction with in-situ materials. Our trials with sulfur based concrete and sintered lunar regolith simulant made by NASA show strong promise. Our project ultimately aims at demonstration of lunar outpost infrastructure construction involving landing pads, blast walls, roads, shade walls and protective hangars. This paper reports on our very early efforts in the first stage of the project.

null

Zengshe, Liu Paul, Calvert

2018-11-28T16:28:21Z

1997

Mechanical Engineering

doi:10.15781/T2QZ23331

http://hdl.handle.net/2152/70320

eng

1997 International Solid Freeform Fabrication Symposium

Open

['SFF', 'control charts', 'SPC']

Extrusion Freeform Fabrication of Bone-Like Mineralized Hydrogels and Muscle-like Actuators

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d14b5cc6-0d1c-4c2a-bff9-d2749e5ed0d0/download

null

Extrusion freeform fabrication has been used to build shapes from agarose, polyacrylamide and polyacrylic acid hydrogels. Contraction and bending can be induced by pH change or application ofa voltage between embedded electrodes. Mineral reinforcement can be induced by incorporating salts into the gels and allowing them to react.

null

['Vaidyanathan, R.', 'Lombardi, J.L', 'Walish, J.']

2019-03-13T16:28:28Z

1999

Mechanical Engineering

null

['https://hdl.handle.net/2152/73643', 'http://dx.doi.org/10.26153/tsw/785']

eng

1999 International Solid Freeform Fabrication Symposium

Open

['EFF', 'SFF']

Extrusion Freeform Fabrication of Functional Ceramic PrototypeS

Conference paper

https://repositories.lib.utexas.edu//bitstreams/01106edb-2a5c-4020-bb04-50593e9c55ba/download

null

Extrusion Freeforming (EFF) and Fused Deposition Modeling (FDM) processes are established freeforming techniques capable of fabricating complex shaped ceramic prototypes by the sequential deposition and solidification of green ceramic feedstock, layer by layer until the final part results. The freeforming of ceramic parts was accomplished using a commercially available Stratasys 3D Modeler retrofitted with a high-pressure extrusion head designed by Advanced Ceramics Research, Inc. (ACR). The manufactured objects had good dimensional tolerances, as well as real engineering compositions and microstructures. Ceramic feedstock based on two different silicon nitride powders were developed and successfully used to make prototype parts. Mechanical properties and microstructural characterization of prototype parts were performed.

null

['Lombardi, John L.', 'Calvert, Paul D.']

2018-12-05T20:39:24Z

1997

Mechanical Engineering

doi:10.15781/T2R49GW1M

http://hdl.handle.net/2152/71417

eng

1997 International Solid Freeform Fabrication Symposium

Open

['CAD', 'EFF']

Extrusion Freeforming of Nylon 6 Materials

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5409b20f-049a-4ceb-af6b-a637b8ea82f0/download

null

Numerous commercial rapid prototyping (RP) processes are capable offabricating complex shaped components. These processes build prototypes "from the ground up" by first reducing a CAD design ofthe desired prototype to a series ofgeometrical slices followed by the precise sequential deposition ofraw material layers upon one another. Unfortunately, these RP processes are limited to producing prototypes from polYmers that exhibit inferior mechanical properties compared to commercial engineering thermoplastics. Consequently, there are significant advantages in extending the materials processing capabilities ofRP technology into the realm ofproducing tough, high strength functional prototypes from engineering polYmers.

null

['Calvert, Paul', 'Crockett, Robert', 'Lombardi, John', "O'Kelly, John", 'Stuffle, Kevin']

2018-09-26T19:45:15Z

1994

Mechanical Engineering

doi:10.15781/T2XD0RG99

http://hdl.handle.net/2152/68590

eng

1994 International Solid Freeform Fabrication Symposium

Open

['SFF', 'ACR Systems', 'polymer extrusion']

Extrusion Methods For Solid Freeform Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e36d145a-4894-4dab-9fe5-2ba7d2894745/download

null

It is becoming clear that current SFF methods are members of a potentially very large family. As with current forming methods, it is to be expected that particular materials and objects will lend themselves best to particular methods. Our group has been working for two years on extrusion methods of freeform fabrication where a reactive slurry is extruded into a pattern to form a series of layers that build up a three-dimensional object. A sketch of the apparatus is shown in figure 1. The slurry may cure chemically either as each layer forms or in a postcuring oven. As a member of the SFF family, this method offers great versatility in the range of materials that can be formed an in control ofthe material structure and composition within a part. This paper describes our efforts to extend the application of this method from ceramics to polymer composites, thermoplastics and silica-silica composites.

null

['Jin, Y.', 'Plott, J.', 'Shih, A.J.']

2021-10-19T20:09:23Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89329

eng

2015 International Solid Freeform Fabrication Symposium

Open

['extrusion-based additive manufacturing', 'additive manufacturing', 'moisture-cured silicone elastomer', 'silicone elastomer']

Extrusion-Based Additive Manufacturing of the Moisture-Cured Silicone Elastomer

Conference paper

https://repositories.lib.utexas.edu//bitstreams/55aa485e-1e74-4109-97cb-7cabdb561896/download

University of Texas at Austin

The extrusion-based additive manufacturing (AM) of moisture-cured silicone elastomer for complex freeform shape is studied. Due to its low elastic modulus and poor shape retaining ability during the layer-by-layer process, silicone elastomer AM is technically challenging. The experiment for extrusion of room temperature vulcanization silicone elastomer is conducted to study effects of air pressure, nozzle size and speed, layer height and distance between silicone lines on the flow rate and cross-sectional geometry of silicone elastomer AM. The COMSOLTM Multiphysics simulation using the level function to track the silicone-air interface is applied to model the silicone flow. Modeling and experimental results of the diameter and flow rate of silicone under the free flowing condition has good agreement and shows the potential for model-based guidelines for AM of silicone elastomers. Effects of the nozzle speed, layer height, and distance between two adjacent lines are investigated and demonstrate the feasibility and limitations of AM of silicone elastomer.

null

['Lipton, Jeffrey I.', 'Cohen, Daniel', 'Heinz, Michael', 'Lobovsky, Maxim', 'Parad, Warren', 'Bernstein, Garrett', 'Li, Tianyou', 'Quartiere, Justin', 'Washington, Kamaal', 'Umaru, Abdul-Aziz', 'Masanoff, Rian', 'Granstein, Justin', 'Whitney, Jordan', 'Lipson, Hod']

2021-09-28T18:31:19Z

2009-09

Mechanical Engineering

null

['https://hdl.handle.net/2152/88149', 'http://dx.doi.org/10.26153/tsw/15090']

eng

2009 International Solid Freeform Fabrication Symposium

Open

['Fab@Home', 'business model', 'SFF market']

Fab@Home Model 2: Towards Ubiquitous Personal Fabrication Devices

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c46c014c-fc87-4f0a-9bf1-51c534aae91f/download

University of Texas at Austin

The open-architecture, open-source Fab@Home platform has proven to be an important system within the SFF community. In order to facilitate wider spread of the Fab@Home platform and SFF throughout the world, we aimed to improve critical aspects of the system, and business model. By changing the electronics package and streamlining the mechanics, the cost of the system was brought from $2500 to $1600. By changing the business model we hope to transform the SFF market and spur innovation.

null

['Lipton, Jeffrey', 'MacCurdy, Robert', 'Boban, Matt', 'Chartrain, Nick', 'Withers III, Lawrence', 'Gangjee, Natasha', 'Nagai, Alex', 'Cohen, Jeremy', 'Sobhani, Karina', 'Liu, Jimmy', 'Qudsi, Hana', 'Kaufman, Jonathan', 'Mitra, Sima', 'Garcia, Aldo', 'McNioll, Anthony', 'Lipson, Hod']

2021-10-04T20:42:56Z

8/17/11

Mechanical Engineering

null

['https://hdl.handle.net/2152/88343', 'http://dx.doi.org/10.26153/tsw/15282']

eng

2011 International Solid Freeform Fabrication Symposium

Open

['Solid Freeform Fabrication', 'Fab@Home', 'Fab@Home Model 3', 'user base technology', 'cost reduction']

Fab@Home Model 3: A More Robust, Cost Effective and Accessible Open Hardware Fabrication Platform

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c9eca8a6-cb13-4557-8e00-438b0cbb4873/download

University of Texas at Austin

Solid Freeform Fabrication is transitioning from an industrial process and research endeavor towards a ubiquitous technology in the lives of every designer and innovator. In order to speed this transition Fab@Home Model 3 was created with the goal of expanding the user base of SFF technology by lowering the skill and price barriers to entry while enabling technology developers to leverage their core competencies more efficiently. The result is a device, which is modular with respect to tool heads, fabrication processes, and electronics controls, costs under $1000, and requires only a simple tool set to assemble.

null

['Malone, Evan', 'Lipson, Hod']

2020-03-05T19:51:42Z

2006

Mechanical Engineering

null

['https://hdl.handle.net/2152/80150', 'http://dx.doi.org/10.26153/tsw/7171']

eng

2006 International Solid Freeform Fabrication Symposium

Open

Solid freeform fabrication

Fab@Home: The Personal Desktop Fabricator Kit

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4391d032-1114-484a-b5b9-37575db243fa/download

null

Solid freeform fabrication has the potential to revolutionize manufacturing, perhaps even to allow consumers to customize and manufacture goods cost-effectively in their own home. At present, the florescence of the technology is limited by a “chicken and egg” paradox. There is insufficient consumer demand and too narrow a range of applications for SFF systems to allow mass production to reduce their cost and complexity. At the same time, consumer applications for, demand for, and indeed awareness of SFF technology is limited by its high cost and complexity. We posit that just as the personal computer revolution was spurred by development of computer kits, getting SFF technology into the hands of hobbyists and hackers will simultaneously generate applications for, and improvements to it. To this end, we have developed the Fab@Home personal SFF kit, and are developing a user-group website to promote exchange of ideas and improvements. The designs and software for Fab@Home will be freely distributed, and constructing a first generation kit should cost roughly $2000. The kit design and a working unit will be presented, along with our experience deploying a unit for public use.

null

['Li, Wenbin', 'Martin, Austin J.', 'Kroehler, Benjamin', 'Henderson, Alexander', 'Huang, Tieshu', 'Watts, Jeremy', 'Hilmas, Gregory E.', 'Leu, Ming C.']

2021-11-10T21:50:23Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90188', 'http://dx.doi.org/10.26153/tsw/17109']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['dynamic mixing', 'functionally graded materials', 'fabrication', 'ceramic on-demand extrusion', 'CODE']

Fabricating Functionally Graded Materials by Ceramic On-Demand Extrusion with Dynamic Mixing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8030ba9b-16f9-47e1-b8fb-1b22752a27c1/download

University of Texas at Austin

Ceramic On-Demand Extrusion (CODE) is an extrusion-based additive manufacturing process recently developed for fabricating dense, functional ceramic components. Presented in this paper is a further development of this process focusing on fabrication of functionally graded materials (FGM). A dynamic mixing mechanism was developed for mixing constituent ceramic pastes, and an extrusion control scheme was developed for fabricating specimens with desired material compositions graded in real time. FGM specimens with compositions graded between Al2O3 and ZrO2 were fabricated and ultimately densified by sintering to validate the effectiveness of the CODE process for FGM fabrication. Energy dispersive spectroscopy (EDS) was used to compare final compositions to the original material designs. The specimen’s hardness at different locations along the gradients was examined by micro-indentation tests. The dimensions of sintered specimens were measured, and the effects of material composition gradients on the distortions of sintered FGM specimens were analyzed.

null

['Lyons, Alan M.', 'Mullins, John', 'Barahman, Mark', 'Erlich, Itay', 'Salamon, Todd']

2021-09-29T14:39:59Z

2009-09

Mechanical Engineering

null

['https://hdl.handle.net/2152/88184', 'http://dx.doi.org/10.26153/tsw/15125']

eng

2009 International Solid Freeform Fabrication Symposium

Open

['superhydrophobic surfaces', 'multi-jet modeling rapid prototying']

Fabricating Superhydrophobic Surfaces with Solid Freeform Fabrication Tools

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3923016b-fd9a-467a-a307-c9a8c2a9c72f/download

University of Texas at Austin

Superhydrophobic surfaces exhibit a range of properties such as large contact angle, low contact angle hysteresis and decreased hydrodynamic drag. These properties make superhydrophobic surfaces of fundamental and commercial interest as they can enable a wide variety of applications including microfluidic components, biomedical devices, and micro-batteries. Superhydrophobic behavior is achieved through a combination of the hydrophobicity of the polymer and the roughness of the surface. We have used a commercially available multi-jet modeling rapid prototyping machine to fabricate 3D objects where the superhydrophobic surface is monolithic with the part. This approach was used to fabricate non-planar components with novel structures including helical conduits and porous meshes. In addition, we have developed a robotic dispensing tool that enables greater freedom of material selection. Both approaches have been used to fabricate arrays of surface features with diameters below 175 microns and with aspect ratios greater than 8:1. The fabrication and wetting properties of surfaces made using these two techniques will be discussed.

null

['Li, Wenbin', 'Ghazanfari, Amir', 'McMillen, Devin', 'Scherff, Andrew', 'Leu, Ming C.', 'Hilmas, Gregory E.']

2021-11-02T19:08:42Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89867

eng

2017 International Solid Freeform Fabrication Symposium

Open

['ceramic on-demand extrusion', 'zirconia', 'support structure', 'CODE']

Fabricating Zirconia Parts with Organic Support Material by the Ceramic On-Demand Extrusion Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/0c6075ca-1641-478f-8369-c4b7bbb75696/download

University of Texas at Austin

Ceramic On-Demand Extrusion (CODE) is an extrusion-based additive manufacturing process recently developed for fabricating dense, functional ceramic components. This paper presents a further development of this process and focuses on fabricating 3 mol% yttria-stabilized zirconia (3YSZ) components that cannot be fabricated without using support structures. The 3YSZ paste is deposited through the main nozzle, and a polycaprolactone (PCL) pellet feedstock is melted and deposited through an auxiliary nozzle to build support structures. After a green part is printed and dried, the support structures are removed by heating the part to ~70 °C to melt the PCL. The part is then sintered at 1550 o C to achieve near theoretical density. The maximum angle of overhanging feature that can be fabricated without support was determined to be 60°. Sample parts were fabricated and evaluated to demonstrate the effectiveness of the PCL support material and CODE’s capability to fabricate geometrically complex parts.

null

['Miyanaji, Hadi', 'Akbar, Junaid Muhammad', 'Yang, Li']

2021-11-02T19:02:28Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89866

eng

2017 International Solid Freeform Fabrication Symposium

Open

['binder jetting process', 'saturation', 'composite', 'liquid phase sintering']

Fabrication and Characterization of Graphite/Nylon 12 Composite via Binder Jetting Additive Manufacturing Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e39d3a71-5f41-4de9-a75d-9af04fe4167b/download

University of Texas at Austin

Nowadays, graphite is used in many applications due to its unique combination of physical properties. Fabrication of graphite parts has been mostly restricted to traditional manufacturing processes (e.g. moldering), and limited works have been devoted to the feasibility of additive manufacturing (AM) technology to produce graphite components. In the present study, the feasibility of binder jetting additive manufacturing (BJ-AM) process in fabrication of graphite/nylon composites is investigated. The printability of the composite parts with varying graphite amount was experimentally examined through the adjustment of in-process parameters (e.g. saturation level and drying energy) and post-processing curing (e.g. curing time and temperature). The efficiency of nylon as the liquid phase sintering agent was studied via the mechanical property evaluation of the composites. In addition, the electrical properties of the graphite/nylon composites were investigated in order to evaluate the effectiveness of the manufacturing method for graphite-based structures for potential functional applications.

null

['Zhou, Bin', 'Zhou, Jun', 'Li, Hongxin', 'Lin, Feng']

2021-11-04T18:16:44Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/89995', 'http://dx.doi.org/10.26153/16916']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['electron beam selective melting', 'selective laser melting', 'hybrid', 'Ti6Al4V']

Fabrication and Characterization of Ti6Al4V by Selective Electron Beam and Laser Hybrid Melting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b6b84749-05e9-4cfd-9f2d-66bd30de9564/download

University of Texas at Austin

A hybrid process, which combines electron beam selective melting(EBSM) and selective laser melting(SLM), is proposed in this study. Laser is led into the vacuum chamber through the lens so that laser can be used to fabricate the metal powder at the same time with electron beam. In this study, Laser is used to pre-preheat the metal powder in order to preventing powder spreading and laser is also used to fabricate the contour of the parts both inside and outside. Electron beam is used to preheat the metal powder to the specified temperature and to fabricate the interior of the parts. It can be sure that through the hybrid process we can fabricate the parts with both better surface quality, higher precision and higher efficiency. Ti6Al4V samples were fabricated by selective electron beam and laser hybrid melting. The surface roughness of the parts was measured, the microstructures of the contour and interior were characterized using scanning electron microscopy (SEM). The results are that as-fabricated parts have better surface quality than the parts fabricated only using EBM process.

null

['Holt, Nicholas', 'Galvan Marques, Lucas', 'Van Horn, Austin', 'Montazeri, Mahsa', 'Zhou, Wenchao']

2021-11-03T22:01:49Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89946

eng

2017 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'MAPS', 'microheaters', 'MEMS', 'PID controls']

Fabrication and Control of a Microheater Array for Microheater Array Powder Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/07ac87d5-ed9d-43b6-8f26-eee2f6c9d08b/download

University of Texas at Austin

Microheater Array Powder Sintering (MAPS) is a novel additive manufacturing process that uses a microheater array to replace the laser of selective laser sintering as the energy source. Most of the previous research on microheaters are for applications in gas sensing or inkjet printing. The operation temperature and response time of the microheater array are critical for the choice of sintering materials and printing speed for the MAPS process. In this paper, we present the fabrication, packaging, and control of a platinum microheater array that has a target operation temperature of 400°C and a response time of ~1 millisecond. First, we will present the fabrication process of a microheater array. The fabricated microheater array is then packaged for easy control and to serve as the printhead of the MAPS process. A PID controller is designed to control the temperature response of the microheater. Finally, the effectiveness of the controller is evaluated. Results show the fabricated microheater array satisfies the design requirements for the MAPS process.

null

['Dunbar, Alexander J.', 'Gunderman, Gabrielle J.', 'Mader, Morgan C.', 'Reutzel, Edward W.']

2021-11-08T22:46:32Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90062', 'http://dx.doi.org/10.26153/tsw/16983']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['powder bed fusion', 'CT', 'Inconel 625', 'heat exchanger']

Fabrication and Quality Assessment of Thin Fins Built Using Metal Powder Bed Fusion Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6a542fef-8821-40ca-ac56-48534b6c5b0b/download

University of Texas at Austin

Powder bed fusion additive manufacturing (PBFAM) is well suited for the fabrication of metallic components with thin features that would be otherwise impractical using other manufacturing methods. As component designs begin to take full advantage of the capabilities of additive manufacturing, so must the capability of measurement techniques used in assessment of quality increase. The characterization of quality may be application specific, requiring different metrics for different uses, e.g. impact on thermal vs. mechanical considerations. Here, thin fins are built with a wide range of processing conditions to test the limits of thin, metallic components using PBFAM. These thin fins are inspected using novel computed tomography (CT) based measurement techniques to assess their build quality. Within the process parameters tested, fins were successfully built thinner than manufacturer-recommended minimum wall thickness using default process parameters. The quality of these fins was assessed utilizing post-build non-destructive evaluation techniques developed herein.

null

['Alayavalli, Kaushik', 'Bourell, David L.']

2021-09-30T23:57:28Z

9/23/10

Mechanical Engineering

null

['https://hdl.handle.net/2152/88300', 'http://dx.doi.org/10.26153/tsw/15241']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['bipolar plates', 'graphite parts', 'indirect Selective Laser Sintering', 'Direct Methanol Fuel Cells']

Fabrication and Testing of Graphite Bipolar Plates for Direct Methanol Fuel Cells

Conference paper

https://repositories.lib.utexas.edu//bitstreams/0125a682-bf6a-4093-a78a-9366dbeedd4f/download

University of Texas at Austin

Bipolar plates made from graphite are highly desirable in fuel cell applications due to the properties of high electrical conductivity, low weight and resistance to corrosion that graphite possesses. However, the poor mechanical properties of natural graphite lead to prohibitive machining costs. Graphite parts are made by indirect SLS using graphite powder mixed with a phenolic resin binder which is subsequently burnt out. These parts fabricated using indirect SLS have poor green strength and electrical conductivity. The current work deals with the addition of carbon fiber to the graphite-phenolic mixture with an aim to improve green part strength and brown part conductivity. This research work also addresses fabrication of graphite bipolar plates for Direct Methanol Fuel Cells (DMFCs) with internal features and flow channels with different cross-sectional geometry that are difficult to produce using conventional machining processes.

null

['Anstaett, C.', 'Seidel, C.', 'Reinhart, G.']

2021-11-04T14:02:57Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89963

eng

2017 International Solid Freeform Fabrication Symposium

Open

['multi-material fabrication', 'material property', 'manufacturing process', 'laser-based powder bed fusion', 'laser beam melting']

Fabrication of 3D Multi-Material Parts Using Laser-Based Powder Bed Fusion

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4a325bb8-2a15-41da-be6a-9522c17c26cf/download

University of Texas at Austin

As different branches of industry use Laser Beam Melting (LBM) and more and more materials can be produced with it, this technology goes in and out of focus of production technologies in an industrial environment. A big advantage of LBM is the possibility of building very complex parts and therefore minimizing the need for raw material. The effects of this, such as lightweight-design, resource-efficient production and reduction of manufacturing time, can even be increased if material can be used locally defined in a part, so that one part does not have to consist of one material per fabrication-process, but at least two. Since LBM is a powder-bed-based process, the implementation of this idea is possible by adopting the conventional delivery device and the manufacturing process itself. In this paper the results of a multi-material process are shown and the influences of different material properties on the manufacturing process are derived.

null

['Hu, Qin', 'Liu, Yaan', 'He, Yinfeng', 'Zhang, Fan', 'Wildman, Ricky', 'Tuck, Chris', 'Hague, Richard']

2021-10-21T15:38:53Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89399

eng

2015 International Solid Freeform Fabrication Symposium

Open

['nano-composites', 'two-photon lithography', 'gold nanostructures', 'nanofabrication', 'polymerisation', 'metal salt reduction', 'metamaterials']

Fabrication of 3D Polymer-Metal Nano-Composites in a Single Step by Two-Photon Induced Polymerisation and Metal Salt Reduction

Conference paper

https://repositories.lib.utexas.edu//bitstreams/15586193-25cf-400e-820d-17a34148549a/download

University of Texas at Austin

Fabrication of 3D polymer-metal nano-composites in a single step by two-photon induced polymerisation and metal salt reduction has been demonstrated in this study. Two kinds of composites, SU8-Au and IPL-Au, based on different mechanisms of polymerisation, have been fabricated and compared. To the best of our knowledge, this is the first demonstration of IPL-Au nano-composites being fabricated by two-photon lithography. Extra photoninitator is needed for the fabrication of IPL-Au composites, to provide extra free radicals to sustain the two reactions processing at the same time. The distribution of the generated Au nanoparticles in IPL matrix is more uniform than that in SU8 matrix. The technique demonstrated in this study can have great application in metamaterial fabrication.

null

['Fuhrman, Brian T.', 'Duty, Chad E.', 'Jean, Daniel L.', 'Lackey, W. Jack']

2019-09-23T17:11:34Z

2000

Mechanical Engineering

null

['https://hdl.handle.net/2152/75977', 'http://dx.doi.org/10.26153/tsw/3076']

eng

2000 International Solid Freeform Fabrication Symposium

Open

Thermionic

Fabrication of Advanced Thermionic Emitters Using Laser Chemical Vapor Deposition-Rapid Prototyping 498

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4f821899-c292-4088-a6f5-721bc88210dc/download

null

Laser Chemical Vapor Deposition-Rapid Prototyping (LCVD-RP) is a relatively new manufacturing process. Its capabilities are ideally suited for the manufacturing of a type of electron emitter called an integrated-grid thermionic emitter. The integrated-grid thermionic emitter is composed of wagon wheel-like structures of alternating layers of boron nitride and molybdenum on tungsten. The goal of this paper is to determine the feasibility of using LCVDRP technology to manufacture advanced thermionic emitters.

null

['Tan, George Z.', 'Zhou, Yingge']

2021-11-16T15:21:34Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90311', 'http://dx.doi.org/10.26153/tsw/17232']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['divergence electrospinning', '3D nanofiber scaffold', 'tissue engineering']

Fabrication of Aligned Nanofibers Along Z-Axis – A Novel 3D Electrospinning Technique

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6a776f18-f904-4e37-8348-7519b97e11d6/download

University of Texas at Austin

This study presents a 3D fabrication technique of nanofibrous scaffold for tissue engineering. A divergence static electric field was introduced in an electrospinning system to induce a self-assembly of aligned nanofibers into a tunable 3D architecture with thickness ranging from 2-12 mm. The effects of collector configuration on polycaprolactone (PCL) nanofiber attributes were investigated. Human fibroblast cells were cultured on the nanofiber scaffold in vitro for 7 days. It was found that the width and inclination angle of the collector influenced the nanofiber density distribution. The cells proliferated on the scaffold and organized as a fibrous matrix which mimicked the microstructure of native musculoskeletal tissues.

null

['Ott, A.', 'Heinzl, J.', 'Janitza, D.', 'Pelzer, R.']

2020-02-20T18:23:23Z

2004

Mechanical Engineering

null

['https://hdl.handle.net/2152/80034', 'http://dx.doi.org/10.26153/tsw/7056']

eng

2004 International Solid Freeform Fabrication Symposium

Open

computer tomography

Fabrication of Bone Substitute Material by Rapid Prototyping

Conference paper

https://repositories.lib.utexas.edu//bitstreams/187ae983-7179-4f7f-95fc-f8c5ad6cf016/download

null

Bone tissue engineering has gained much attention in recent years. A key requirement in this field is the development of scaffold structures, on which cells adhere. This can be done by fabricating scaffolds by direct procedures like 3D-printing or by indirect procedures like casting. With the 3D-printing process different structures were build up by using hydroxyapatite powder (HA) and a special binder material. Afterwards the printed 3D structures were sintered. For the casting process molds have been made of different resins by stereolithography and other processes using polymers and waxes. These structures were filled by a suspension of HA. By heating the resulting polymer/ceramic composite to a specific temperature it is possible to combust the polymer or wax. By further heating the remaining body, the HA is sintered. Compared to the 3D printing a better resolution can be obtained here. But there are restrictions regarding the ratio of polymer and the HA ceramic during the heating process which means a limitation for the level of porosity.

null

['Snelling, Dean', 'Williams, Christopher', 'Suchicital, Carlos', 'Druschitz, Alan']

2021-10-21T19:27:37Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89429

eng

2015 International Solid Freeform Fabrication Symposium

Open

['binder jetting', 'cellular cordierite', 'ceramic preforms', 'metal matrix composites']

Fabrication of Cellular Cordierite Performs via Binder Jetting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c8ba8365-1846-4671-97b3-c00ede38bfa6/download

University of Texas at Austin

Metal Matrix Composites (MMCs) combine two dissimilar materials – a metal as the matrix and a ceramic as the charge or insert to provide unique properties, e.g. low density, high specific strength, high specific modulus, and wear resistance. The ceramic inserts in these composite materials are limited to ceramic fibers and open cell stochastic ceramic foams due to geometric constraints imposed by traditional manufacturing processes. The geometric design freedom offered by Additive Manufacturing (AM) could enable a designer to realize ceramic preforms with complex cellular geometries that are designed to achieve multiple functions (e.g., low mass and increased stiffness). The goal of this work is to explore the use of Binder Jetting as a means of fabricating cordierite parts of designed mesostructure for use as ceramic preforms for MMCs. In this paper, the authors describe their exploration of the appropriate printing process parameters and post-process sintering parameters that enable successful fabrication of complex cordierite artifacts. Measurements of bulk density, linear shrinkage, porosity, and x-ray diffraction are conducted on pre- and post-sintered printed cordierite structures.

null

['Deckard, Lucy', 'Claar, T. Dennis']

2018-05-03T19:13:43Z

1993

Mechanical Engineering

doi:10.15781/T2251G32W

http://hdl.handle.net/2152/65060

eng

1993 International Solid Freeform Fabrication Symposium

Open

["Lanxide's matrix", 'CMC', 'Ceramix Matrix Composites', 'DIMOX']

Fabrication of Ceramic and Metal Matrix Composites From Selective Laser Sintered Ceramic Preforms

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4d827fa3-21f7-46e1-820d-d1a820bbf7c6/download

null

This paper will discuss the tool~less fabrication of functional advanced comJX>sites by infusion of a ceramic or metal matrixinto Selective Laser Sintered(SLS) porous ceranU~preforms using Lanxide'spatentedmatrix infusionproc;esses. The fabri~ationofJX>rous preformS of particulate cerami~sby SLS atthe University ofTexas at Austin is described in a companion paper. The PRlME}(TI4 pressureless metal infi1trationp~ss was used to infiltrate<alUIninum matrices into both SiC and Al~03 particulate SLS prefonns to make metal matrix comJX>sites withoutthe use of tooling. Also, SiC I~03 ceramic matrix comJX>sites were fabricated using the DIMO}(TI4 directed metal oxiJation process to grow an Al20 3 matrix into porous SiC particulate SLS preforms. Measured properties and microstructures of the resulting composites will be presented and compared to similar comJX>sites made using conventionally fabricated preforms. The rapid prototyping of a SiCiAIMMC electronic power package to near~net shape from an SLS preform will also be describeQ.

null

['Wang, X.', 'de Caussin, D.']

2021-11-09T21:05:23Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90167', 'http://dx.doi.org/10.26153/tsw/17088']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['ceramics', 'photopolymers', 'digital light projection', 'tape casting', 'projection-based stereolithography']

Fabrication of Ceramic Parts Using a Digital Light Projection System and Tape Casting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e62d7a8b-93ee-4427-9c92-5c918c0e99c4/download

University of Texas at Austin

In this paper, fabrication of ceramic parts using projection-based stereolithography by curing the mixture of ceramic and photopolymers was investigated. A stereolithography device with a UV LED projection light source was built. A series of resin and ceramic powders, including alumina and zirconia, were experimented to explore the viscosity of mixture and the resultant part quality. It was found that commercial photopolymers are not suitable for this purpose due to the small cure depth. A customized photopolymer without photoinhibitor and optimized photoinitator has demonstrated success in producing 3D ceramic green bodies. It was found that the viscosity was very high for all of the mixtures with high ceramic loading which will influence the recoating process. Therefore, tape casting was used to apply the slurry during the build process.

null

['Choi, Jae-Won', 'Park, In-Baek', 'Wicker, Ryan', 'Lee, Seok-Hee', 'Kim, Ho-Chan']

2021-09-28T17:45:32Z

9/10/08

Mechanical Engineering

null

['https://hdl.handle.net/2152/88134', 'http://dx.doi.org/10.26153/tsw/15075']

eng

2008 International Solid Freeform Fabrication Symposium

Open

['microstereolithography', '3D micro-scale scaffolds', 'tissue enginnering']

Fabrication of Complex 3D Micro-Scale Scaffolds and Drug Delivery Devices using Dynamic Mask Projection Microstereolithography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/08a55ab2-e04f-4626-bd33-146a3d91c7bc/download

University of Texas at Austin

Microstereolithography (μSL) technology can fabricate three-dimensional (3D) tissue engineered scaffolds with controlled biochemical and mechanical micro-architectures. A μSL system for tissue engineering was developed using a Digital Micromirror Device (DMDTM) for dynamic pattern generation and an ultraviolet (UV) lamp filtered at 365 nm for crosslinking the photoreactive polymer solution. The μSL system was designed with x-y resolution of ~2 μm and a vertical (z) resolution of ~1 μm. To demonstrate the use of μSL in tissue engineering, poly(propylene fumarate) (PPF) was synthesized with a molecular weight of ~1200 Da. The viscosity of the PPF was reduced to ~150 cP (at 50 o C) by mixing with diethyl fumarate (DEF) in the ratio of 7:3 (w/w). Finally, ~2 % (w/w) of (bis(2,4,6- trimethylbenzoyl) phenylphosphine oxide (BAPO) was added to the solution to serve as a photoinitiator. Cure depth experiments were performed to determine the curing characteristics of the synthesized PPF, and the resulting system and photopolymer were used to construct a variety of 3D porous scaffolds with interconnected pores between 100 and 150 μm and a micro-needle array with height of ~800 μm and individual tip diameters of ~20 μm. SEM and microscope images of the micro-architectures illustrate that the developed μSL system is a promising technology for producing biodegradable and biocompatible microstructures.

null

['Lous, G.M.', 'Cornejo, I.A.', 'McNulty, T.F.', 'Safari, A.', 'Danforth, S.C.']

2019-03-01T17:37:35Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73518', 'http://dx.doi.org/10.26153/tsw/668']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['Fused Deposition', 'Ceramics']

Fabrication of Curved Ceramic / Polymer Composite Transducers for Ultrasonic Imaging Applications by Fused Deposition of Ceramics

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4a1977c2-3962-4a74-9082-ede968979961/download

null

Fused Deposition of Ceramics (FDC), developed at Rutgers University, is a Solid Freeform Fabrication (SFF) technique where a three-dimensional green ceramic object is built layer by layer, starting from a Computer Aided Design (CAD) file of the object. This technique was used to build novel piezoelectric ultrasonic transducers for medical imaging applications. Curved ceramic skeletons for 2-2 (parallel ceramic / epoxy plates) composite transducers were built by FDC. The design's curvature can be tailored in the CAD file. Therefore, the final composite requires very little machining. In the FDC-built green parts, the ceramic plates were 500 um thick and the spacing between the plates was 1270 um. The FDC green samples were subjected to a slow binder burnout cycle at 550°C for 4 hours, using a heating rate of 8°C per hour, then sintered at 1285°C for 1 hour. Physical characterization of the samples revealed that 95% ofthe theoretical density was achieved. The ceramic plates shrunk 20% in height as well as in width. The shrinkage was of only 16% in the direction parallel to the plates. Optical microscopy and SEM were performed on green and sintered samples. The results of these characterizations are reported in this paper as well as the electromechanical properties of the final composites and of FDC bulk samples.

null

['Gervasi, Vito', 'Cook, Douglas', 'Rizza, Robert', 'Kamara, Sheku']

2021-09-29T17:44:46Z

10/7/09

Mechanical Engineering

null

['https://hdl.handle.net/2152/88199', 'http://dx.doi.org/10.26153/tsw/15140']

eng

2009 International Solid Freeform Fabrication Symposium

Open

['custom orthosis', 'rapid prototyping', 'additive manufacturing', 'laser sintering', 'foam molding', 'polypropylene', 'polyamide']

Fabrication of Custom Dynamic Pedorthoses for Clubfoot Correction via Additive-Based Technologies

Conference paper

https://repositories.lib.utexas.edu//bitstreams/59de9528-2ac6-4e0e-8b9a-9c44a9475b2e/download

University of Texas at Austin

Additive technologies have created many opportunities to improve the quality of life for patients in a range of medical applications. This paper provides an overview of how several of these technologies were leveraged to transform custom pedorthosis designs into physical, end-use, custom pedorthoses for clubfoot patients. The pedorthoses that were produced are currently being tested on the respective patients for their improvement in mobility and degree of clubfoot correction, and will continue through early 2010. The advantage of this approach is the reduction in labor and the increase in degrees of design freedom available, compared to conventional methods of fabricating orthotic devices. Several new approaches for fabricating custom orthotic devices that were explored, and the related results, are discussed.

null

['Alayavalli, Kaushik', 'Bourell, David L.']

2020-03-11T14:35:42Z

9/10/08

Mechanical Engineering

null

['https://hdl.handle.net/2152/80245', 'http://dx.doi.org/10.26153/tsw/7264']

eng

2008 International Solid Freeform Fabrication Symposium

Open

['Selective Laser Sintering', 'SLS', 'DMFC', 'Direct Methanol Fuel Cell']

Fabrication of Electrically Conductive, Fluid Impermeable Direct Methanol Fuel Cell (DMFC) Graphite Bipolar Plates by Indirect Selective Laser Sintering (SLS)

Conference paper

https://repositories.lib.utexas.edu//bitstreams/26192c1b-6071-4779-abe9-a33db912ca24/download

null

Graphite bipolar plates are highly desirable due to their properties of high electrical conductivity and low weight but are associated with prohibitive machining costs arising from poor mechanical properties. Bipolar plates made by indirect Selective Laser Sintering (SLS) offer the advantages of complex part production in shorter times at lower cost. Due to the nature of the SLS process, the as-produced (green part) plates are porous and possess low electrical conductivity which can be improved by carbonizing the phenolic resin binder at high temperatures (brown part). It has been found that the electrical conductivity increases significantly (> 200 S/cm) with a corresponding increase in pyrolyzing temperature which correlates well with literature on the carbonization of phenol formaldehyde resins. The brown parts are subsequently infiltrated with low viscosity (~5 - 10 cps) cyanoacrylate to seal up the open pores, rendering the plates fluid impermeable.

null

['Choi, Jae-Won', 'Quintana, Rolando', 'Wicker, Ryan B.']

2021-09-28T17:41:17Z

9/10/08

Mechanical Engineering

null

['https://hdl.handle.net/2152/88132', 'http://dx.doi.org/10.26153/tsw/15073']

eng

2008 International Solid Freeform Fabrication Symposium

Open

['micro-fluidic devices', 'embedded horizontal micro-channels', 'line-scan stereolithography', 'micro-fluidic fabrication', 'micro-channel fabrication']

Fabrication of Embedded Horizontal Micro-Channels Using Line-Scan Stereolithogrpahy

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1ec6c06f-4663-4b08-a1e5-cdcfddbc70ed/download

University of Texas at Austin

In an effort to directly and rapidly manufacture micro-fluidic devices with embedded horizontal micro-channels on the order of tens of microns, a method was developed for using current commercially available line-scan stereolithography (SL) technology. The method consisted of inserting a wire of specified diameter during the build, building around the inserted wire, and removing the wire once fabricated leaving a channel with a circular cross-sectional geometry equivalent to the wire diameter. Demonstration of the technique using 31.6 µm, 57.2 µm and 83.5 µm wire was performed using a 3D Systems Viper si2TM SL system and DSM Somos® WaterShedTM resin. By embedding the wire and building around the insert, the down-facing surfaces were supported during fabrication enabling successful and accurate fabrication of embedded micro-channel geometries. A method for successful fabrication was developed that involved first building an open micro-channel, interrupting the SL process and inserting the wire, and then capping over the wire with multiple layers. After fabricating a part with a micro-wire, the micro-channel was produced by simply pulling the wire out of the part. Scanning electron microscope (SEM) images were used to examine and measure the geometries of the fabricated micro-channels, and a statistical design of experiments was performed to show that the process was capable of producing accurate horizontal micro-channels. It is expected that this process will enable unique micro-fluidic and other applications of micro-channel fabrication to be pursued using commercial line-scan SL.

null

['Sun, Lianchao', 'Jakubenas, Kevin J.', 'Crocker, James E.', 'Harrison, Shay', 'Shaw, Leon L.', 'Marcus, Harris L.']

2018-12-05T20:42:23Z

1997

Mechanical Engineering

doi:10.15781/T2MC8S278

http://hdl.handle.net/2152/71418

eng

1997 International Solid Freeform Fabrication Symposium

Open

['SFF', 'thermocouples']

Fabrication of In-situ SiC/C Thermocouples by Selective Area Laser Deposition

Conference paper

https://repositories.lib.utexas.edu//bitstreams/ee3abc95-9f1a-4428-b768-5f0dfab6318b/download

null

With the intrinsic nature to process relatively small features, selective area laser deposition (SALD) is a potential technique to fabricate complex shaped macro-components with in-situ high-resolution micro-devices. In this study, SALD was used to deposit in-situ silicon carbide/carbon (SiC/C) thermocouples on alumina and silicon carbide substrates with a C02 laser. Tetramethylsilane (TMS) and acetylene (C2H2) were chosen as precursors for deposition of the silicon carbide and carbon lines respectively. The electromotive force (emf) ofthe deposited thermocouple was measured and found to respond sensitively to temperature variations from room temperature to 800°C. The effect ofthe deposition parameters on the product morphology was also investigated.

null

['Jiang, Wenhui', 'Kovacevic, Radovan']

2019-11-21T18:23:33Z

2003

Mechanical Engineering

null

['https://hdl.handle.net/2152/78557', 'http://dx.doi.org/10.26153/tsw/5613']

eng

2003 International Solid Freeform Fabrication Symposium

Open

TiC/Steel

Fabrication of Laser Deposited TiC/Steel Matrix Composite Coatings

Conference paper

https://repositories.lib.utexas.edu//bitstreams/16bf826d-69c3-45da-9b6f-1fb838b5ac28/download

null

The present work investigates the effect of laser scanning beam speeds and the content of TiC in injected powder on morphologies and microstructures of laser deposited beads of a TiC/H13 tool steel composite. The results show that the beam scanning speeds affect the size and morphology of the beads. During laser processing, TiC melts, decomposes, and subsequently, a number of fine TiC precipitates form during cooling that are uniformly distributed in the tool steel matrix. The beam scanning speeds and the amount of injected TiC exert a strong influence on the morphology and size of the fine TiC precipitates. It is believed that the precipitated TiC is the primary phase in hypereutectic Fe-TiC. Rapid cooling develops martensite with retained austenite in a steel matrix. The precipitated TiC can refine grains of the steel matrix as a solidified nucleus. TiC/H13 tool steel composite coatings with various contents of TiC were produced using the laser deposition processing technique.

null

['Brown-Moore, Tosh Kāneala', 'Balaji, Srivatsan', 'Williams, Tyler', 'Lipton, Jeffrey']

2023-01-26T14:27:57Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117306', 'http://dx.doi.org/10.26153/tsw/44187']

eng

2022 International Solid Freeform Fabrication Symposium

Open

voronoi

Fabrication of Liquid-Filled Voronoi Foams for Impact Absorption Using Material Jetting Technology

Conference paper

https://repositories.lib.utexas.edu//bitstreams/052f20d0-ea8f-4a86-9d24-69b31bd937aa/download

null

An important consideration in the design of any mechanical system is its ability to isolate and dissipate vibrational and impact energy. Closed-cell foams utilize cell crumpling to absorb energy, relying solely on viscoelastic effects for damping. Liquids, however, can generate large amounts of damping from fluid channel friction and turbulence. We produced closed-cell foams that are liquid filled, resulting in tunable materials that absorb energy better than either component on their own, using a Voronoi generation model and a J750 printer that could jet curable and incurable liquids. We found that by changing the wall thickness and liquid percentage, we achieve a stiffness range of 4.1 N/mm to 80 N/mm. Our work introduces this new class of damping metamaterial that can absorb tunable amounts of energy per unit volume. These impact-absorbing structures may benefit applications such as protective equipment, healthcare, and automotive industries.

null

['Brueckner, Frank', 'Riede, Mirko', 'Mueller, Michael', 'Marquardt, Franz', 'Knoll, Matthias', 'Willner, Robin', 'Seidel, André', 'Lopéz, Elena', 'Leyens, Christoph', 'Beyer, Eckhard']

2021-11-08T21:48:50Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90050', 'http://dx.doi.org/10.26153/tsw/16971']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['laser metal deposition', 'multi-material alloys', 'metal alloys', 'highly-loaded areas', 'fabrication']

Fabrication of Metallic Multi-Material Components Using Laser Metal Deposition

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b2697640-2a67-4425-a148-f905bf13899c/download

University of Texas at Austin

Meanwhile, Laser Metal Deposition (LMD) is a well-known Additive Manufacturing technology used in various industrial branches as energy, tooling or aerospace. It can be used for the fabrication of new components but also repair applications. So far, volume build-ups were mostly carried out with one single material only. However, loading conditions may strongly vary and, hence, the use of more than one material in a component would yield major benefits. By means of multi-material build-ups, cost-intensive alloys could be used in highly-loaded areas of the part, whereas the remaining part could be fabricated with cheaper compositions. The selection of combined materials strongly depends on the requested thermo-physical and mechanical properties. Within this contribution, possibilities of material combinations by LMD and selected examples of beneficial multi-material use are presented.

null

['Johnson, Ryan W.', 'Bondi, Scott N.', 'Jean, Daniel L.', 'Duty, Chad E.', 'Jang, Ming Xuan', 'Lackey, W. Jack']

2019-10-09T16:07:25Z

2001

McDonald Observatory

null

['https://hdl.handle.net/2152/76148', 'http://dx.doi.org/10.26153/tsw/3237']

eng

2001 International Solid Freeform Fabrication Symposium

Open

Fabrication

Fabrication of Multi-Layered Carbon Structures Using LCVD

Conference paper

https://repositories.lib.utexas.edu//bitstreams/0b451753-a453-4d65-8624-d50959581e73/download

null

Others have used Laser Chemical Vapor Deposition (LCVD) to create 3-D fibrous structures and helical springs. Current research efforts focus on the creation of more advanced three-dimensional carbon objects through the use of multi-layered deposition. Multi-layered structures require an understanding of interlayer adhesion and the propagation of geometric anomalies through multiple layers. An important aspect in minimizing these shape anomalies is the implementation of closed loop temperature control. Several laminated carbon structures are presented with discussions and observations about the fabrication process and visual characteristics of each. The major issues in using LCVD to create multi-layer carbon structures are addressed.

null

['Zhang, Wande', 'Han, Li-Hsin', 'Chen, Shaochen']

2021-09-28T18:18:14Z

9/24/09

Mechanical Engineering

null

['https://hdl.handle.net/2152/88144', 'http://dx.doi.org/10.26153/tsw/15085']

eng

2009 International Solid Freeform Fabrication Symposium

Open

['nanoimprinting molds', 'acrylic polymer', 'two-photon polymerization']

Fabrication of Nanoimprinting Molds with Acrylic Polymer by Two-Photon Polymerization

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a1e7e976-c564-4329-8e9c-c34125e07e0e/download

University of Texas at Austin

We demonstrate the plausibility of making low-cost nanoimprinting molds with acrylic polymer using femtosecond-laser-induced two-photon polymerization (TPP) technique. A Ti:sapphire femtosecond laser was used to induce TPP in dipentaerythritol pentaacrylate to make nanostructures, the nanoimprinting mold, on pretreated glass substrate. A layer of fluoro-silane was then grown on the surface of the mold to promote the release of the mold after imprinting. To test the imprinting capacity of the mold, poly (ethylene glycol) diacrylate was patterned by the mold and the results were analyzed by a scanning electron microscope (SEM).

null

Partanen, Jouni P.

2018-11-09T14:56:37Z

1996

Mechanical Engineering

doi:10.15781/T23F4M712

http://hdl.handle.net/2152/69922

eng

1996 International Solid Freeform Fabrication Symposium

Open

['SLA', 'RP&M technologies', 'laser']

Fabrication of Parts Containing Small Features using Stereolithography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9b3e48e7-f682-4c1c-9a3b-54f27a9053fa/download

null

The StereoLithography (SL) process has benefited from many advances in the last four to five years. These include new resins with reduced shrinkage and curl distortion, enhanced software, and improved scanning techniques. One can produce highly accurate parts for most dimensions within a few mils of the design value as shown in numerous accuracy and benchmarking studies. SLA systems use a laser beam focused to a spot size of 200 -250 ~m. This limits the range of applications where SL can provide accurate models to parts which do not contain very small features i. e. wall thickness values less than about 300 ~m. Industries that manufacture products involving components with small features include electronics and medical. In this presentation we describe an extension of the SL technology to applications involving small features. This capability is achieved by reducing the laser focal spot size in an SLA-250 to 75 ~m. The technological principle behind the spot size reduction is described in the presentation, together with process issues and applications ofthe technology.

null

['Chen, Ssuwei', 'Bourell, David L.', 'Wood, Kristin L.']

2020-02-13T19:26:02Z

8/23/04

Mechanical Engineering

null

['https://hdl.handle.net/2152/79965', 'http://dx.doi.org/10.26153/tsw/6990']

eng

2004 International Solid Freeform Fabrication Symposium

Open

Selective Laser Sintering

Fabrication of PEM Fuel Cell Bipolar Plates by Indirect SLS

Conference paper

https://repositories.lib.utexas.edu//bitstreams/cd5b6342-956b-46dc-9858-ea9bcbe92ca1/download

null

The paper presents a new manufacturing technique involving Selective Laser Sintering (SLS) for proton exchange membrane fuel cell (PEMFC) bipolar plate fabrication. A material system for bipolar plate fabrication was identified to satisfy both the cell performance requirement and SLS operation restriction. Carbonization and liquid epoxy infiltration are subsequently performed following the completion of SLS green bipolar plate. The finished SLS bipolar plate showed impressive surface finish and mechanical strength, and a single fuel cell was assembled with two SLS end plates and membrane electrode assembly (MEA) in between. Various physical property tests were performed with positive results. Fuel cell performance (voltage vs. current density, voltage vs. time, etc.) will be assessed in the near future.

null

['Rogers, W.E.', 'Crawford, R.H.', 'Beaman, J.J.', 'Walsh, N.E.']

2018-04-17T16:44:33Z

1991

Mechanical Engineering

doi:10.15781/T2XD0RF4F

http://hdl.handle.net/2152/64331

eng

1991 International Solid Freeform Fabrication Symposium

Open

['SLS workstation', 'CAD system', 'SLS']

Fabrication of Prosthetic Socket by Selective Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c8017c2a-f34b-455f-9abc-c3f776b457a7/download

null

Solid freeform fabrication technologies offer exciting possibilities for improving product quality by direct manufacture of products. .One example of such product improvement is the fabrication of artificial limb sockets by selective laser sintering (SLS). Currently these sockets are produced at the University of Texas Health Science Center at San Antonio by digitizing the residual limb with a 3D laser scanner, modifying this geometry appropriately using a proprietary CAD system, producing a mold with a computer-controlled milling machine, and vacuum forming the final product. This paper describes a new manufacturing technique whereby the digital socket data from the CAD system provide input to a SLS workstation to produce the final socket directly, without the intermediate step of fabricating a mold pattern. The advantages of this process include integration of the prosthesis attachment fitting and socket as one component and greater control of local socket geometry for superior stress relief characteristics.

null

['Pan, Yayue', 'Chen, Yong', 'Zhou, Chi']

2021-10-04T21:34:12Z

2011

Mechanical Engineering

null

['https://hdl.handle.net/2152/88355', 'http://dx.doi.org/10.26153/tsw/15294']

eng

2011 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'surface finish', 'layer stair-stepping', 'mask projection stereolithography']

Fabrication of Smooth Surfaces Based on Mask Projection Stereolithography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6e1a9904-9935-488c-a0d5-3b6a70761e8e/download

University of Texas at Austin

The surface finish is critical for applications such as micro-fluid mixing and self-assembly that requires smooth fluidic flow and mechanical rotation respectively. However, in layer-based additive manufacturing processes, it is well known that the stair-stepping effect exists in the fabricated surfaces since a three-dimensional model is approximated by a set of two-dimensional layers. The fabricated surfaces are especially poor for the ones that are close to the horizontal plane. In this paper a novel approach for achieving improved surface finish has been presented for the mask-image-projection-based Stereolithography (MIP-SL) process. Theoretical models and parameter characterization are presented with experimental verification. The developed approaches have been incorporated in the process planning of the MIP-SL process. Multiple test cases based on various types of curved surfaces have been performed. A comparison of the built results based on the traditional and the newly developed approaches has been discussed to illustrate the effectiveness of our method.

null

['Jayabal, Dinesh Krishna Kumar', 'Zope, Khushbu', 'Cormier, Denis']

2021-11-09T20:17:03Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90154', 'http://dx.doi.org/10.26153/tsw/17075']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['engineered lattice structures', 'lattice structures', '4043 aluminum', 'molten aluminum droplets', 'magneto hydro dynamic jetting', 'jetting']

Fabrication of Support-Less Engineered Lattice Structures via Jetting of Molten Aluminum Droplets

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d8601c40-69a5-4afd-a3c9-37de48335991/download

University of Texas at Austin

Magneto Hydro Dynamic (MHD) jetting is a promising new metal additive manufacturing technique that employs on-demand jetting of molten metal droplets onto a moving substrate. A particularly unique aspect of the process is its potential to print down-facing features without the need for support structures. Under suitable droplet jetting conditions affecting time and temperature, each droplet at least partially solidifies prior to impact of the next incoming molten metal droplet. The combination of droplet jetting frequency and substrate velocity dictates the stepover distance between incoming droplets. With relatively large droplet step-over distances (or equivalently small percentage of droplet overlap), it is possible to print unsupported down-facing features that are nearly parallel to the X-Y build platform. In this paper, we describe initial results in which engineered lattice structures have been printed using 4043 aluminum using this approach. A parametric study that maps jetting frequency and droplet step-over distance with the resulting lattice strut angle is presented. With careful control of jetting parameters, we show that it is possible to print nearly horizontal lines without any support.

null

['Liu, Weiping', 'DuPont, John']

2019-10-22T18:19:57Z

2002

McDonald Observatory

null

['https://hdl.handle.net/2152/76334', 'http://dx.doi.org/10.26153/tsw/3423']

eng

2002 International Solid Freeform Fabrication Symposium

Open

Matrix

Fabrication of Titanium Aluminide Matrix Composites by Laser Engineered Net Shaping

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6fd123a1-5d73-42de-9432-98c80d922a64/download

null

TiAl-based titanium aluminide alloys and their composites reinforced with ceramic particles are considered to be important candidate materials for high temperature structural applications. Laser Engineered Net Shaping (LENS) is a layered manufacturing process, which involves laser processing fine powders into three-dimensional components directly from a CAD design. In this work, the LENS process has been employed to fabricate carbide particle reinforced titanium aluminide matrix composites using TiC and gas-atomized Ti-48Al-2Cr-2Nb powders as the feedstock materials. The composites deposited by the LENS process exhibited a susceptibility to solid-state cracking due to the generated high thermal stresses. The microstructures of the laser-deposited monolithic and composite titanium aluminide materials were characterized using light optical microscopy and XRD techniques. Effects of the LENS processing parameters on the cracking susceptibility and microstructure were studied. Crack-free deposits can be fabricated by preheating the substrate to 450~500°C during LENS processing. The fabricated composite deposits exhibit a hardness of more than twice the value of the Ti-6Al-4V alloy.

The authors gratefully acknowledge support of this work by the National Science Foundation through a PECASE Award, Grant No. DMI 9983968, made through the Division of Manufacturing and Industrial Innovation of NSF.

null

['Beal, V. E.', 'Erasenthiran, P.', 'Hopkinson, N.', 'Dickens, P.', 'Ahrens, C. H.']

2020-02-12T16:03:21Z

8/17/04

Mechanical Engineering

null

['https://hdl.handle.net/2152/79944', 'http://dx.doi.org/10.26153/tsw/6970']

eng

2004 International Solid Freeform Fabrication Symposium

Open

['Functionally Graded Material', 'laser fusion']

Fabrication of X-Graded H13 and Cu Powder Mix Using High Power Pulsed Nd:YAG Laser

Conference paper

https://repositories.lib.utexas.edu//bitstreams/25bb2ab4-7951-4f33-9039-0041a0718066/download

null

The manufacturing of Functionally Graded Material (FGM) parts using Solid Free Form manufacturing technologies has been carried out since early 1980. At present, most of the powder manufacturing techniques are being focused on layering powder with different powder blend compositions with Z gradients (graded in direction of layer build). Although, there are a few researchers working on multi powder feeder and deposition system, the study of laser fusion of the deposited powder (by a powder deposition system) is minimum or not known to date. Consequently, the manufacturing of functionally graded structures is still geometry limited. This work was focused on the manufacturing of X-graded (graded along the powder bed plane) specimens with H13 tool steel and Cu mix. Five bimodal powder blends were used with a multi-container feed hopper to spread powder layers for the selective laser fusion of the powder. The powder was fused using a high power Nd:YAG pulsed laser using a specific scanning strategy to reduce porosity. Specimens were produced with graded Cu within the H13 matrix. The specimens were analysed for dimensional accuracy, microstructure, porosity, cracks and micro hardness of the FGM.

null

['Zhang, Yicha', 'Harik, Ramy', 'de Backer, Wout', 'Bernard, Alain']

2021-10-26T17:48:09Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89537

eng

2016 International Solid Freeform Fabrication Symposium

Open

['build orientation', 'alternatives', 'facet clusters', 'additive manufacturing']

A Facet Cluster-Based Method for Alternative Build Orientation Generation in Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2b7cc879-da1a-4f21-b305-1de1f20bd664/download

University of Texas at Austin

Build orientation determination is an important pre-processing step in Additive Manufacturing. To identify an optimal build orientation, there are two main tasks, generating a set of alternative orientations and evaluating these alternatives with pre-set criteria. To solve the first task, currently there are two categories of methods, exhaustive computing and continuous surface decomposition. However, for exhaustive computing methods, the infinite original alternative orientation space is an obstacle, especially when considering multiple objectives. While the other type of methods have difficulty on surface separation and shape boundary recognition when facing complex CAD models. To tackle of these obstacles, this paper introduces a new method applying a statistical tool to form facet clusters for decomposing an STL model in a discrete way. The formed facet clusters can be used to efficiently generate meaningful alternative build orientations and can also be used to predict surface quality distribution over a part model for further process planning or design iteration.

null

['Zhang, Zhicheng', 'Fidan, Ismail']

2021-11-30T21:04:13Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90548', 'http://dx.doi.org/10.26153/tsw/17467']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['failure detection', 'deep learning', 'printing error', 'fused filament fabrication']

Failure Detection of Fused Filament Fabrication via Deep Learning

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f3e0ec34-1e71-4653-a903-8f8f2dff08b0/download

University of Texas at Austin

Additive Manufacturing (AM) is used in several fields and its utilization is growing sharply in almost every aspect of daily life. The focus of the current studies in the AM field is generally focused on the development of new technologies and materials. In addition, there is a limited number of research studies on the troubleshooting aspects of the AM processes. For the most commonly used Fused Filament Fabrication (FFF) process, the waste of material and time due to the printing errors are still an unsolved problem. The typical errors such as nozzle jamming and layer mis-alignment are inevitable during the printing process, and thus cause the failure of printing. It is a challenging task to clearly understand the physical behavior of FFF process with uncertainty, due to the phase transition and heterogeneity of the materials. Therefore, to detect the printing error, this research proposes a deep learning (DL) based printing failure detection technique. In this study, DL is utilized to monitor the printing process, and detect its failures. This newly developed DL framework was beta-tested with a commercially available FFF setup. The beta testing results showed that this technique could effectively detect printing failures with high accuracy.

null

['Zhang, Runyu', 'Jiao, Yuxin', 'Paniagua, Christopher', 'Tian, Yi', 'Lu, Hongbing', 'Li, Wei']

2023-01-27T17:55:27Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117349', 'http://dx.doi.org/10.26153/tsw/44230']

eng

2022 International Solid Freeform Fabrication Symposium

Open

['Wire-arc additive manufacturing (WAAM)', 'porosity propagation', 'in-situ X-ray micro-computed tomography (μCT)']

The Failure of Wire-Arc Additive Manufactured Aluminum Alloys with Porosities under Loadings as Observed by In-situ X-Ray Micro-Computed Tomography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9446a9a8-5c74-4198-bbce-e98b7f29c3bd/download

null

Wire-arc additive manufactured aluminum alloys (WAAM 4043 Aluminum) are widely used in many industries. Porosities are known to exist within the WAAM aluminum alloys, which greatly reduces the usability and reliability of such parts. In this study, WAAM aluminum alloy samples with porosities are manufactured using a Fronius (TPS 320i) MIG/MAG welding and ABB (IRB 140) robot system. The porosities generated inside the samples and the porosity evolution under the uniaxial tension are observed using in-situ X-ray micro-computed tomography (μCT). The μCT system with an integrated mechanical loading frame provides in-situ volumetric images of the specimens while loadings are applied. The porosity evolution of the WAAM aluminum samples and the propagation of the internal pores are assessed. This work provides direct experimental observations and evaluations of the influence of porosities on the mechanical behavior of WAAM aluminum alloys under loadings.

null

['Carton, M.A.', 'Ganter, M.']

2021-11-30T21:44:13Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90560', 'http://dx.doi.org/10.26153/tsw/17479']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['auxetic structures', 'fused deposition modeling', 'FDM printing']

Fast and Simple Printing of Graded Auxetic Structures

Conference paper

https://repositories.lib.utexas.edu//bitstreams/19119ee8-79db-4f3f-992a-ed1b33e8c0f9/download

University of Texas at Austin

One of the great promises of additive manufacturing is the ability to build parts with volumetrically graded parameters that would be difficult or impossible with traditional manufacturing. This paper presents a method of procedural generation and unsupported fabrication of 2D objects patterned with functionally graded auxetic (negative Poisson’s ratio) cellular structures using commercially available FDM printers. Several types of two-dimensional auxetic pattern are fabricated. The resulting printed objects exhibit a graded response to load, deforming corresponding to local patterning. Deformation is studied using imaging of loaded structures and applications in several areas are considered.

null

['Yan, Lei', 'Pan, Tan', 'Newkirk, Joseph W.', 'Liou, Frank', 'Thomas, Eric E.', 'Baker, Andrew H.', 'Castle, James B']

2021-11-09T19:07:41Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90128', 'http://dx.doi.org/10.26153/tsw/17049']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['thermal history', 'heat source', 'thermal prediction', 'large-scale parts', 'finite element analysis', 'laser metal deposition']

Fast Prediction of Thermal History in Large-Scale Parts Fabricated Via a Laser Metal Deposition Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c9e55e1f-3f54-43f4-bfa4-ecae5f3a49f9/download

University of Texas at Austin

Laser metal deposition (LMD) has become a popular choice for the fabrication of near-net shape complex parts. Plastic deformation and residual stresses are common phenomena that are generated from the intrinsic large thermal gradients and high cooling rates in the process. Finite element analysis (FEA) is often used to predict the transient thermal cycle and optimize processing parameters; however, the process of predicting the thermal history in the LMD process with the FEA method is usually time-consuming, especially for large-scale parts. Herein, multiple 3D FEA models with simple assumptions on the heat source and its loading methods are compared and validated with experimental thermocouple data.

null

Wilkening, Christian

2018-11-09T16:23:16Z

1996

Mechanical Engineering

doi:10.15781/T22F7K997

http://hdl.handle.net/2152/69930

eng

1996 International Solid Freeform Fabrication Symposium

Open

['RP-processes', 'DMLS', 'DCP']

Fast Production of Technical Prototypes Using Direct Laser Sintering of Metals and Foundry Sand

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b7712620-b7d3-4b1a-baad-f0c17235fd18/download

null

Currently most RP-Parts are used for visualisation, assembly checks and some functional testing. The next stage between these functional prototypes and the pre-series is technical prototypes, which are used for final functional testing and optimisation of the production process. These must not only have the same material as the series parts, but must also be manufactured with the same production process. Due to the second ofthese requirements layer manufacturing processes cannot be used to build these prototypes directly, but they can be used to make the negative moulds or tools. Two new RP-processes based on laser sintering now have the capability to produce the moulds and tools via very short and fast process chains. Both have already been in commercial use in Europe for about one year. The first process manufactures tools for injection moulding of plastic parts by Direct Metal Laser Sintering (DMLS). The second process, called the Direct Croning Process (DCP), is used to build sand moulds and cores for sand casting of metal parts directly from Croning-Sand without any tools. These technologies have been developed by EOS GmbH, Munich, and are marketed under the names EOSINT M and EOSINT S respectively

null

['Pan, Yayue', 'Chen, Yong', 'Zhou, Chi']

2021-10-06T22:23:34Z

2012

Mechanical Engineering

null

['https://hdl.handle.net/2152/88458', 'http://dx.doi.org/10.26153/tsw/15395']

eng

2012 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'high-speed fabrication', 'fast recoating', 'stereolithography']

Fast Recoating Methods for the Projection-based Stereolithography Process in Micro- and Macro-Scales

Conference paper

https://repositories.lib.utexas.edu//bitstreams/59cb8899-e4c6-40c2-9a8d-5366b513c21d/download

University of Texas at Austin

The purpose of this paper is to present a recoating method for the development of a direct digital manufacturing (DDM) process that can be an order of magnitude faster than other currently available DDM processes. In the mask-image-projection-based Stereolithography (MIP-SL) process, projection light controlled by a Digital Micromirror Device (DMD) can quickly cure liquid photopolymer resin in a whole area; a fast recoating method is required for achieving truly high-speed fabrication. We investigate the bottom-up projection system in the MIP-SL process. For the macro-scale MIP-SL process, a two-way linear motion approach has been developed for the quick spreading of liquid resin into uniform thin layers. In comparison, a direct pull-up motion can be used in the micro-scale MIP-SL process. The system design and related settings for achieving a fabrication speed of a few seconds per layer are presented. Additionally, the hardware, software, and material setups for fabricating three-dimensional (3D) digital models are presented. Experimental studies using the developed testbed have been performed to verify the effectiveness and efficiency of the presented fast MIP-SL process.

null

Wales

2018-04-16T17:42:57Z

1991

Mechanical Engineering

doi:10.15781/T21834K30

http://hdl.handle.net/2152/64313

eng

1991 International Solid Freeform Fabrication Symposium

Open

['FDM', 'CAD systems', 'CAM systems']

Fast, Precise, Safe Prototypes with FDM

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3da99502-25b7-4ab5-a347-6be6150b6116/download

null

Knirsch, James R.

2020-02-17T15:13:03Z

8/19/04

Mechanical Engineering

null

['https://hdl.handle.net/2152/80007', 'http://dx.doi.org/10.26153/tsw/7032']

eng

2004 International Solid Freeform Fabrication Symposium

Open

rapid production tooling

Faster - Better Molds Through RSP Tooling New Research and Advancements

Conference paper

https://repositories.lib.utexas.edu//bitstreams/970a3a9e-50b5-4031-a608-5814977e92de/download

null

The recent developments in rapid production tooling have all but made the need for prototype tooling disappear. There are several approaches that are now as fast and inexpensive as prototype tooling, and after part approval can continue to run in high volume production applications. The newest of these approaches is an indirect spray forming process invented by Dr. Kevin McHugh of the Idaho National Engineering and Environmental Laboratories (INEEL). The advantages of RSP Tooling can be found in its accuracy, finish, cost and speed compared to the other rapid tooling processes [1]. The commercialization effort for this spray forming process started in February of 2002. The beta production machine was operational in November, 2003, and started to produce production tooling in March, 2004. Since that time tooling has been manufactured and run for many forming applications. In all but the simplest tools the process has proven to be less expensive and faster than standard machining of tools or any other rapid production tooling process. Research and development of the process has continued both at INEEL and at RSP Tooling, LLC making the process faster, more accurate and less expensive to operate. This research has also generated a better understanding of the underlying metallurgy of the process.

null

['Stoffregen, Hanns A.', 'Butterweck, Katja', 'Abele, Eberhard']

2021-10-13T20:34:01Z

2014

Mechanical Engineering

null

['https://hdl.handle.net/2152/88779', 'http://dx.doi.org/10.26153/tsw/15713']

eng

2014 International Solid Freeform Fabrication Symposium

Open

['fatigue life', 'selective laser melting', 'thin-walled housings', 'piezoceramic actuators', 'cyclic loads']

Fatigue Analysis in Selective Laser Melting: Review and Investigation of Thin-Walled Actuator Housings

Conference paper

https://repositories.lib.utexas.edu//bitstreams/7ab0b42f-c561-469a-89be-84e013d9b674/download

University of Texas at Austin

The versatile applicable selective laser melting (SLM) is a promising manufacturing technology that allows 3-dimensional design freedom for complex and challenging load bearing parts. A specific application of SLM is the production of thin-walled housings for piezoceramic actuators which induce cyclic loads. Although there are investigations on the fatigue behavior of SLM-specimens, wide acceptance of SLM is limited by a lack of knowledge concerning the operating behavior of actual parts. This paper presents a review on existing studies about fatigue life analysis in SLM as well as results from uniaxial high cycle fatigue (HCF) tests of 1.4542 stainless steel as-built and machined specimens with a stress ratio of R = 0. Due to a lower surface roughness machined specimens show significantly higher fatigue strength compared to as-built ones. The obtained fatigue strength at 107 cycles of as-built specimens is used as input for fatigue tests of thin-walled actuator housings. Numerical simulation is used to determine the stress distribution of thin-walled as-built actuator housings under specific loads. Results indicate that the thin-walled as-built actuator housing withstand higher peak stresses compared to as-built specimens due to a high stress gradient.

null