ccm/sff-papers · Datasets at Hugging Face

['Maines, Erin', 'Bell, Nelson', 'Evans, Lindsey', 'Roach, Matthew', 'Tsui, Lok-kum', 'Lavin, Judith', 'Keicher, David']

2021-11-10T21:11:30Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90176', 'http://dx.doi.org/10.26153/tsw/17097']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['low viscosity resin', 'ceramic slurries', 'material properties', 'stereolithography', 'additive manufacturing']

Material Properties of Ceramic Slurries for Applications in Additive Manufacturing Using Stereolithography

Conference paper

https://repositories.lib.utexas.edu//bitstreams/18c401e4-9f99-40ec-bfa5-2d742f4e3383/download

University of Texas at Austin

Stereolithography (SL) is a process that uses photosensitive polymer solutions to create 3D parts in a layer by layer approach. Sandia National Labs is interested in using SL for the printing of ceramic loaded resins, namely alumina, that we are formulating here at the labs. One of the most important aspects for SL printing of ceramics is the properties of the slurry itself. The work presented here will focus on the use of a novel commercially available low viscosity resin provided by Colorado Photopolymer Solutions, CPS 2030, and a Hypermer KD1 dispersant from Croda. Two types of a commercially available alumina powder, Almatis A16 SG and Almatis A15 SG, are compared to determine the effects that the size and the distribution of the powder have on the loading of the solution using rheology. The choice of a low viscosity resin allows for a high particle loading, which is necessary for the printing of high density parts using a commercial SL printer. The Krieger-Dougherty equation was used to evaluate the maximum particle loading for the system. This study found that a bimodal distribution of micron sized powder (A15 SG) reduced the shear thickening effects caused by hydroclusters, and allows for the highest alumina powder loading. A final sintered density of 90% of the theoretical density of alumina was achieved based on the optimized formulation and printing conditions.

null

['Josupeit, Stefan', 'Lohn, Johannes', 'Hermann, Eduard', 'Gessler, Monika', 'Tenbrink, Stephan', 'Schmid, Hans-Joachim']

2021-10-20T20:44:57Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89357

eng

2015 International Solid Freeform Fabrication Symposium

Open

['laser sintering', 'build cycles', 'refresh cycles', 'refresh rates', 'polyamide 12']

Material Properties of Laser Sintered Polyamide 12 as Function of Build Cycles Using Low Refresh Rates

Conference paper

https://repositories.lib.utexas.edu//bitstreams/74a9b460-ce44-41da-9503-e5dcfd688ff5/download

University of Texas at Austin

Due to long process times at high temperatures, unmolten polyamide 12 material ages during the manufacturing process. Hence, it needs to be refreshed with new material for further build cycles. In application, refresh rates of about 50 % are commonly used. In this work, the recycling optimized material PA 2221 from EOS is analyzed along a series of 13 build and refresh cycles using a reduced refresh rate of 32 %. Before and after every build, the powder is analyzed regarding melt properties determined by MVR and DSC measurements. Thereby, in-process ageing effects are investigated and the steady-state conditions are determined accordingly. In addition, powder properties are directly linked to resulting mechanical and geometrical part properties. Key findings are a robust DSC measurement method for polyamide 12 powder, constant “circulated” material properties after three build/refresh cycles and robust tensile properties along the whole tested powder life cycle. As a result, process conditions of PA 2221 using reduced refresh rates can be derived from this work.

null

['Kaweesa, Dorcas V.', 'Meisel, Nicholas A.']

2021-11-11T15:40:50Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90224', 'http://dx.doi.org/10.26153/tsw/17145']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['digital composite structures', 'voxel size', 'custom design', 'material property', 'functionally graded materials', 'FGMs', 'additive manufacturing']

Material Property Changes in Custom-Designed Digital Composite Structures Due to Voxel Size

Conference paper

https://repositories.lib.utexas.edu//bitstreams/cfc5bf92-265a-4654-b476-f9342718924a/download

University of Texas at Austin

Advances in additive manufacturing enable fabrication of complex structures using functionally graded materials (FGMs) at a voxel level. Prior to developing voxel-based FGM designs using compatible dithering approaches, it is essential to first understand the basic principles of voxel-based digital composite designs. While several research studies exist regarding different representations of composition in voxel-based solid models, there is no extensive research on the material properties of voxel-based digital composite structures. This paper bridges this gap by investigating custom voxel-based designs of digital composite structures. The objective is to determine how the material properties of such structures are impacted by different voxel sizes using the material jetting process. In addition to the material properties, computational time taken to process different voxel sizes is analyzed. By doing so, we gain a better understanding of the relationship between material composition and voxel size in digital composite structures.

null

['Dinda, Shantanab', 'Banerjee, Dishary', 'Shaffer, Derek', 'Ozbolat, Ibrahim T.', 'Simpson, Timothy W.']

2023-02-09T19:01:35Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117442', 'http://dx.doi.org/10.26153/tsw/44323']

eng

2022 International Solid Freeform Fabrication Symposium

Open

metal implants

Material Selection & Design for Lattice-Based Biodegradable Metal Implants for Bone Regeneration in Load-Bearing Bone Defects

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a62d2168-e877-4706-9a0f-d0409cc5ff01/download

null

Human bone is a dynamic tissue and has a natural ability to repair small fractures quickly; however, critical fractures below the waist require external mechanical aids to help bear loading while healing. These techniques are effective but tend to cause a lack of mobility and decrease quality of life. New materials focused on the biodegradability of implants have opened new avenues in implant design and fabrication, reducing previous concerns such as tunability of degradation rates in such materials. Furthermore, three-dimensional (3D) printed biodegradable metallic implants show promise as an alternative for expediting recovery and increasing mobility, especially with the growth of lattice-based design and better osseointegration techniques. This study discusses the development and testing of a functional AM implant that integrates load-bearing, biodegradability, biocompatibility, and osseointegration, with an eye toward clinical translation. Based on the desired material properties, an iron-manganese mixture is used, along with dopants to aid biocompatibility and improve degradation rates. Lattice-based design has been implemented to reduce material usage without affecting mechanical properties, and the implants have been printed using binder jetting. After fabrication, experiment analysis to evaluate mechanical properties, degradation rates and byproducts, in-vitro performance, and microstructure has been performed for validation, to prepare the implant for in-vivo testing, giving us a functional lattice-based biodegradable metal implant.

null

['Yuan, Mengqi', 'Liu, Yu', 'Qian, Xinming']

2021-11-08T22:54:56Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90066', 'http://dx.doi.org/10.26153/tsw/16987']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['stab resistant', 'body armor', 'carbon fiber', 'polyamide']

Material Selection on Laser Sintered Stab Resistance Body Armor

Conference paper

https://repositories.lib.utexas.edu//bitstreams/466684ea-f92c-4dab-b626-acfa07926ffd/download

University of Texas at Austin

Stab resistant body armor (SRBA) is essential defensive equipment to protect the human body from injury due to stabbing. The conventional SRBAs are heavy and inflexible. Therefore a new type of SRBA has been recently developed using Laser Sintering (LS), which has resulted in a substantial improvement to SRBA in terms of structure and material design. In this development, carbon fiber was employed in the polyamide matrix to obtain the optimal stab resistant performances. Four kinds of materials were used and showed that the polyamide/carbon fiber (PA/CF) composite improved the stab resistance property compared to pure polyamide (PA). The stab resistance performances of flat plates were weaker than structured plates. The penetration depth of the PA/CF structured plate was 2 mm less than the pure PA structured plate. SEM observations of the products confirmed experimental conclusions that the addition of the CF largely improved the plate stab resistance. Moreover, using the PA/CF structured plate to produce SRBA would reduce the weight of the product by 30-40% comparing to the conventional SRBA, which would greatly reduce the physical burden to the wearer and largely improve the chance that the armor would be used.

null

['Shanjani, Yaser', 'Toyserkani, Ehsan']

2021-09-23T21:49:29Z

9/10/08

Mechanical Engineering

null

['https://hdl.handle.net/2152/88030', 'http://dx.doi.org/10.26153/tsw/14971']

eng

2008 International Solid Freeform Fabrication Symposium

Open

['solid freeform fabrication', 'counter-rotating roller', 'powder-based solids', 'mechanical engineering']

Material Spreading and Compaction in Power-Based Solid Freeform Fabrication Methods: Mathematical Modeling

Conference paper

https://repositories.lib.utexas.edu//bitstreams/bee2faf5-a7d5-460c-a6d7-5313374450c9/download

null

In this study, the spreading and compaction of powder by a counter-rotating roller, in the solid freeform fabrication (SFF) process, is modeled and characterized. The effect of layer thickness, roller diameter, amount of loose powder, and its initial density on the powder bed’s relative density and roller compaction pressure is investigated.

null

['Kietzman, J. W.', 'Prinz, F. B.']

2019-02-26T20:22:13Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73497', 'http://dx.doi.org/10.26153/tsw/647']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['SDM', 'support material']

Material Strength in Polymer Shape Deposition Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5c03553e-25e3-45a5-904e-43b3cbb95d62/download

null

Shape Deposition Manufacturing (SDM) is a layered manufacturing process involving an iterative combination of material addition and material removal. Polymer SDM processes have used castable thermoset resins to build a variety of parts. The strength of such parts is determined by the bulk material properties of the part materials and by their interlayer adhesion. This paper describes tensile testing of three thermoset resins used for SDM - two polyurethane resins and one epoxy resin. Both monolithic specimens and specimens with two interlayer !nterfaces were tested. Interlayer tensile strengths were found to vary greatly among the three matenals, from 5-40 MPa.

null

['Damas, Sara M.', 'Turner, Cameron J.']

2021-12-01T23:41:18Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90660', 'http://dx.doi.org/10.26153/tsw/17579']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['conductive pathway', 'material testing', 'ABS', 'nanoparticles', '3D printing']

The Material Testing of Nanoparticle Doped 3D Printed ABS to Decrease Resistance and Create a Conductive Pathway

Conference paper

https://repositories.lib.utexas.edu//bitstreams/017d8e46-6e96-4203-9a7a-4170f5ba88a7/download

University of Texas at Austin

The technology to 3D print by low-cost fabrication has been around since the 1970’s. Thanks to one of its founding fathers, Scott Crump, as of 1989, it is possible to 3D print in low-cost fabricated layers to obtain a solid component. The demand for 3D printed products has only gone up since. Nickel, copper, carbon, and electric paint nanoparticles were bound to Acrylonitrile Butadiene Styrene (ABS) using N-Methyl-2-Pyrrolidinone (NMP) by fused deposition modeling (FDM). When ABS is doped with nanoparticles, conductive properties are introduced to the filament which can then be used for strain measurements. This study concluded: When compared to the other nanoparticles, nickel produced the lowest resistance when doped into the ABS. Multiple layers of the NMP and nanoparticles yields a lower resistance, which subsequently yields higher conductivity. The methodology outlined in this paper successfully created individually isolated conductive pathways, where indeed NMP does improve the conductive performance of the nanoparticles.

null

['Song, Ruoyu', 'Telenko, Cassandra']

2021-10-28T15:48:31Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89668

eng

2016 International Solid Freeform Fabrication Symposium

Open

['material waste', 'commercial FDM printers', 'fused deposition modeling', 'ABS material']

Material Waste of Commercial FDM Printers Under Realistic Conditions

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6c870239-3230-44b9-b1f3-3ea9e471329e/download

University of Texas at Austin

Fused deposition modeling (FDM) is a prominent technology for additive manufacturing. Additive manufacturing is thought to minimize material waste, but the actual material waste could be larger than expected due to human or printer error. In FDM, the quantity of support material is influenced by the part orientation and other settings of the printing. Additionally, failures may result from insufficient preheating time, inappropriate geometry of parts, user error or printer malfunctions. Material waste from commercial FDM printers using ABS material in a heavily utilized open shop was collected in this study. The mass data of both support material and failed prints were recorded over time. In addition, the failed prints were classified into 9 different categories and weighed according to failure reasons. The data were analyzed and indicated that about 34% of the plastic used in the open studio was wasted. Only considering the failed prints as the extra amount of material consumed under realistic conditions, the mass of material lost to failed builds was about 2.22 times what might be estimated in a controlled process study. Suggestions to reduce the material waste for each failure type are given.

null

['Josupeit, Stefan', 'Rüsenberg, Stefan', 'Schmid, Hans-Joachim']

2021-10-07T15:18:52Z

8/16/13

Mechanical Engineering

null

['https://hdl.handle.net/2152/88477', 'http://dx.doi.org/10.26153/tsw/15412']

eng

2013 International Solid Freeform Fabrication Symposium

Open

['polymer laser sintering', 'nylon 12', 'part quality', 'aircraft industry']

A Material-Based Quality Concept for Polymer Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9cd7d1ea-d3d9-4796-ad7d-7c9f44ea3b8c/download

University of Texas at Austin

In this work, the quality of laser sintered parts is investigated along a defined process chain for a nylon 12 material (PA 2200) on an EOSINT P395 laser sintering system. Important influencing factors are figured out. Rheological powder characterization methods are investigated as well as mechanical, physical and other chosen part properties. The concept allows reproducible part quality characteristics and is used to obtain (testing) temperature dependent material data. It can also be extended on further materials based on nylon 12: PA 2241 FR, which is convenient for the aircraft industry due to its flame-retardant properties, and PA 2221, which has economic advantages due to a lower material consumption.

null

Kimble, Luke L.

2018-04-19T18:15:45Z

1992

Mechanical Engineering

doi:10.15781/T20V8B11S

http://hdl.handle.net/2152/64401

eng

1992 International Solid Freeform Fabrication Symposium

Open

['rapid prototyping', 'SLS', 'Selective Laser Sintering']

The Materials Advantage of the SLS Selective Laser Sintering Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8bb792f1-8875-4313-8a8c-6245a885fa46/download

null

The rapid prototyping market continues to progress in tenns of processes and materials used for the creation of conceptual and functional parts and prototype tooling. As this market continues to mature, the market leaders win be able to offer rapid prototyping processes and materials that provide parts which are accurate, have good surface finish, and provide properties which support fqnctional applications.. The materials used for these parts will be. polymers, metals, and ceramics. '. The strength oithe SLSTM Selective Laser Sintering Process is the. potential to use a wide variety of powdered materials for the creation of models, patterns, and some fonns of prototype tooling. ,This paper will cover the types of materials currently used in the SLS process and their inherent advantages.and discuss current research into the development of new materials.

null

['Satapathy, S.', 'Hsieh, K.', 'Persad, C.']

2020-02-12T15:49:19Z

2004

Mechanical Engineering

null

['https://hdl.handle.net/2152/79943', 'http://dx.doi.org/10.26153/tsw/6969']

eng

2004 International Solid Freeform Fabrication Symposium

Open

Electrical Conductor

Materials Design - Towards a Functionally Graded Electrical Conductor

Conference paper

https://repositories.lib.utexas.edu//bitstreams/20df546b-31e6-45dd-9683-1a504bf398c5/download

null

In this study, we discuss functionally graded (FG) materials as pulsed electrical conductors. These conductors can be designed to be more efficient and longer lasting by applying numerical modeling tools. One focus is on limiting the thermal fatigue damage in conductors caused by very high temperatures that develop during pulse heating. We have quantified the effect of various grading functions on the pulsed Joule heating generated and the peak temperature experienced in the conductors of an electromagnetic launcher by using a 1D numerical code and a state of the art 3D coupled finite element code, EMAP3D. Because FG materials incorporate applications-tailored compositions, structures, and dimensions, smoothly graded properties in lateral and longitudinal cross sections are obtainable. The Solid Freeform Fabrication (SFF) processing approach allows for architectures with a series of important features. These features include the selective use of high efficiency conducting materials in the core, preconditioned conductor/structure interfaces, and built-in features for enhanced cooling where necessary.

null

['Barlow, J. W', 'Lee, G.', 'Aufdemorte, T. B.', 'Fox, W. C', 'Swain, L.D.', 'Vail, N.K']

2019-02-27T17:32:04Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73506', 'http://dx.doi.org/10.26153/tsw/656']

null

1998 International Solid Freeform Fabrication Symposium

Open

['selective laser sintering', 'porous']

Materials for Biomedical Applications

Conference paper

https://repositories.lib.utexas.edu//bitstreams/0f6e974e-8e5e-44e6-8d03-cd43f5f6aba6/download

null

This paper discusses two ceramic material systems for selective laser sintering (SLS) that are being developed for biomedical applications for use in repair of bone defects. SLS is the preferred method of fabricating ceramic implants that exhibit well defined porous microstructures. Implants fabricated in this. manner have proven effective in-vivo showing excellent biocompatibility as well as considerable osseous integration and remodeling of the imp'ant material

null

['Cawley, J. D.', 'Liu, Z.', 'Mou, J.', 'Heuer, A. H.']

2019-02-26T17:23:11Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73489', 'http://dx.doi.org/10.26153/tsw/639']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['densification', 'powder compact']

Materials Issues in Laminated Object Manufacturing of Powder-Based Systems

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e64b4115-186f-4da2-a32e-9e9b87d14313/download

null

Laminated object manufacturing offine ceramic and powder metallurgy components can be carried out using either the cut-then-stack or stack-then-cut motif. With either approach, it is necessary to effect laser cutting to define layer geometry and lamination to fuse the stack into a seamless monolith. The relationship between the microstructure of the green tape used as feedstock on the relative ease of each process is reviewed

null

['Schorzmann, J.', 'Gerstl, H.', 'Tan, Z.', 'Sprenger, L.', 'Lu, H.-H.', 'Taumann, S.', 'Wimmer, M.', 'Boccaccini, A.R.', 'Salehi-Muller, S.', 'Dopper, F.']

2024-03-27T15:51:08Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124491', 'https://doi.org/10.26153/tsw/51099']

en

2023 International Solid Freeform Fabrication Symposium

Open

['bioreactor development', 'material screening methodology', 'additive manufacturing', 'material extrusion with thermal reaction bonding', 'biofabrication', '3D-bioprinting']

MATERIALS SCREENING METHODOLOGY FOR ADDITIVE MANUFACTURING IN BIOREACTOR TECHNOLOGY

Conference paper

https://repositories.lib.utexas.edu//bitstreams/0107d2d1-8240-4bb2-bfef-d75f0d412aa6/download

University of Texas at Austin

Biofabrication is used to fabricate complex tissues/organs inspired by their native structures using additive manufacturing (AM) techniques and bio-inks (biopolymers enriched with living cells). Electroactive cells such as skeletal muscle function via electrical signals and therefore, their optimum in vitro functionality requires electrical conductivity and electrical stimulations. AM can be used to precisely fabricate a bioreactor for a dynamic culture of cells and bioengineered tissues and electrical stimulation of them. In this study, we focused on a material selection methodology for AM of bioreactors with selective electrical conductivity based on Reuter [1]. The important material requirements for bioreactors are biocompatibility, chemical stability, electrical conductivity, and the capability of being sterilized. However, there is no standardized procedure for selecting materials, that are appropriate for AM of bioreactors. Our study comprises three phases which deductively narrowed down the material selection; these phases are the determination of material requirements, pre-selection, and fine selection of suitable materials. With the proposed method, a material selection for AM of functional bioreactors (consisting of bioreactor housing and integrated additively manufactured electrodes for electrical stimulation of the cells) could be efficiently made. For the bioreactor housing, two of the investigated materials, high-temperature polylactic acid (HTPLA) and polypropylene (PP) meet all requirements. The materials of the bioreactor electrodes could be narrowed down to polyethylene with copper particles (PE-Cu) and poly lactic acid with graphene nanoplates (PLA-GNP), where PE-Cu fulfilled all requirements besides the biocompatibility. PLA-GNP matches all requirements besides the high temperature resistance. For a final selection of the material for the bioreactor electrodes, further tests are required. However, this approach enabled to reduce the amount of biocompatibility testing from 16 different materials to only four (- 75%), saving material, time, capacity and costs.

null

['Lin, Feng', 'Sun, Wei', 'Van, Yongnian']

2019-03-12T15:49:33Z

1999

Mechanical Engineering

null

['https://hdl.handle.net/2152/73591', 'http://dx.doi.org/10.26153/tsw/733']

eng

1999 International Solid Freeform Fabrication Symposium

Open

['Layered Manufacturing', 'Rapid Prototyping']

A Mathematical Description of Layered Manufacturing Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/46356ecf-0481-4cbd-83dd-2563aa6b97f7/download

null

This study is attempted to use a mathematical definition to describe the principles of Layer Manufacturing Processing. The concept of model decoll1Position (layered subtraction for 3D model slicing) and material accumulation (layered addition for <prot()typjng fabrication) and the associated sequence function and seql.lence· potential to explain·and define the layered manufacturing processing is presented. In the mathematical description, a 3D CAD model is graphically represented by a set of points collected within the bounded surfaces. In addition to its geometric feature, a processing sequence indicator is also assigned to each point as an attribute to associate with its slicing and fabricating·sequence. Model decomposition slices the collected. points into a series of point sets according to their sequence indicator, and material accumulation processes the layered fabrication by stacking the point sets to form the designed object. A scalar field function is used to express the variation of the sequence indicators for the selected point sets and to define iso-sequence planes. The iso-sequence planes are the processing layers consisting of all points with the same sequence indicator. Material accumulation is conducted in the gradient direction of each iso-sequence plane. Example of using proposed scalar field function and the iso-sequence plane for flat and no-flat layered prototyping processing is also presented.

null

Dwivedi, Rajeev

2023-01-26T14:54:32Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117312', 'http://dx.doi.org/10.26153/tsw/44193']

eng

2022 International Solid Freeform Fabrication Symposium

Open

maxel

maxel framework for representing and process planning of Functionally Graded Materials.

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5655e96d-b341-4537-b447-7daa5fe416a3/download

null

Functionally Graded Materials (FGM) are characterized by variation in material composition or density per the required functionality. Inherent ability of various Solid Freeform Fabrication techniques to access bulk volume of part makes it a amenable to fabricating range of functionally graded materials. However, most of the Solid Free Form fabrication follow 2-1/2 additive process. In SFF manufacturing methods the tool path for each layer follows a Zig-zag or similar profile that necessarily is not most optimal path for material delivery. This may led to process inefficiencies. This paper presents a framework based on the maxel representation of materials to enable more efficient and accurate manufacturing of FGMs.

null

['Rodriguez, J. F.', 'Thomas, J.P.', 'Renaud, J. E.']

2019-03-13T16:36:43Z

1999

Mechanical Engineering

null

['https://hdl.handle.net/2152/73644', 'http://dx.doi.org/10.26153/tsw/786']

eng

1999 International Solid Freeform Fabrication Symposium

Open

['Fused-Deposition', 'Solid Freeform Fabrication']

Maximizing the Strength of Fused-Deposition ABS Plastic Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b6d19e26-edf2-420e-84b1-884f969ccf8a/download

null

Fused-Deposition (FD) creates parts using robotic extrusion of set.D.i-liquid .polymer fiber, which molecularly bonds with neighboring fibers via thermal-dlffuslo.n bonding. T~e strength ofthe. part depends on the bulk polymer strength, themesostructure ~flber layout, vOid geom~try, extent of fiber bonding), and thefiber-t~-fiber ~ond strength. The ~nfluence of these factors on the mechanical strength of FD-ABS.plasttc parts IS reported.along with the.FD process variable settingsfor maximum strength. Substantial increases in transverse strength are achieved at the optirnal settings and additional increases can be achieved by post..fabrication annealing. Keywords: Stratasys, fused-deposition, ABSplastic, functional parts, strength, mesostructure, polymer diffusion.

null

['Robinson, C. J.', 'Zhang, C.', 'Janaki Ram, G. D.', 'Siggard, E. J.', 'Stucker, B.', 'Li, L.']

2020-03-02T15:40:39Z

9/14/06

Mechanical Engineering

null

['https://hdl.handle.net/2152/80136', 'http://dx.doi.org/10.26153/tsw/7157']

eng

2006 International Solid Freeform Fabrication Symposium

Open

Ultrasonic Consolidation

Maximum Height to Width Ratio of Freestanding Structures Built Using Ultrasonic Consolidation

Conference paper

https://repositories.lib.utexas.edu//bitstreams/cbf462a5-8a87-47e5-b7da-a9a6c29ef174/download

null

Ultrasonic consolidation (UC) is a process whereby metal foils can be metallurgically bonded at or near room temperature. The UC process works by inducing high-speed differential motion (~20kHz) between a newly deposited layer and a substrate (which consists of a base plate and any previously deposited layers of material). This differential motion causes plastic deformation at the interface, which breaks up surface oxides and deforms surface asperities, bringing clean metal surfaces into intimate contact, where bonding occurs. If the substrate is not stiff enough to resist deflection during ultrasonic excitation of newly deposited layers, then it deflects along with the newly deposited layer, resulting in no differential motion and lack of bonding. Geometric issues which control substrate stiffness and deflection were investigated at Utah State University by building a number of free-standing rib structures with varying dimensions and orientations. Each structure was built to a height where lack of bonding between the previously deposited layers and the newly deposited layer caused the building process to fail, a height to width ratio (H/W) of approximately 1:1. The parts were then cut, polished, and viewed under a microscope. An ANSYS model was created to investigate analytically the cause of this failure. It appears build failure is due to excessive deflection of the ribs around a 1:1 H/W, resulting in insufficient differential motion and deformation to achieve bonding. Preliminary results show, when the H/W reaches 1:1, the von Mises stress is found to be tensile along portions of the bonding interface, which eliminates the compressive frictional forces necessary for plastic deformation and formation of a metallurgical bond. These tensile stresses are shown to be concentrated at regions near the edges of the newly deposited foil layer.

null

['Young, Y.Y.', 'Yu, K.M.', 'Kwong, C.K.']

2019-10-18T15:17:46Z

2001

Mechanical Engineering

null

['https://hdl.handle.net/2152/76235', 'http://dx.doi.org/10.26153/tsw/3324']

eng

2001 International Solid Freeform Fabrication Symposium

Open

Jewel Rings

Maximum Visibility Building Direction for Layered Manufacturing of Jewel Rings

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e52cab88-49fa-4c9e-a1e6-8272b081b690/download

null

Rapid prototyping is used in jewelry production since the introduction of Stereolithography Apparatus into the market. However, the building orientation is mainly decided by the experience of the operator rather than by any systematic analysis. A theory is therefore needed to analyze the best orientation of jewelry in rapid jewelry production. In this paper, a new orientation methodology is applied to jewel ring models to properly orient them for layer manufacturing. Jewel ring model built is then demonstrated to have better quality and less error. A case study is presented to illustrate the theory.

The work described in this paper was supported by a grant from the Hong Kong Polytechnic University (Project No.: G-V617).

null

['Gupta, Guarav', 'Tan, JunJay', 'Seepersad, Carolyn Conner']

2020-03-02T14:33:41Z

2006

Mechanical Engineering

null

['https://hdl.handle.net/2152/80126', 'http://dx.doi.org/10.26153/tsw/7147']

eng

2006 International Solid Freeform Fabrication Symposium

Open

cellular materials

ME Design and Freeform Fabrication of Compliant Cellular Materials with Graded Stiffness

Conference paper

https://repositories.lib.utexas.edu//bitstreams/68ab06e4-9007-441b-ac86-a537f0446519/download

null

Typically, cellular materials are designed for structural applications to provide stiffness or absorb impact via permanent plastic deformation. Alternatively, it is possible to design compliant cellular materials that absorb energy via recoverable elastic deformation, allowing the material to spring back to its original configuration after the load is released. Potential applications include automotive panels or prosthetic applications that require repeated, low-speed impact absorption without permanent deformation. The key is to arrange solid base material in cellular topologies that permit high levels of elastic deformation. To prevent plastic deformation, the topologies are designed for contact between cell walls at predetermined load levels, resulting in customized, graded stiffness profiles. Design techniques are established for synthesizing cellular topologies with customized compliance for static or quasi-static applications. The design techniques account for cell wall contact, large scale deformations, and material nonlinearities. Resulting cellular material designs are fabricated with selective laser sintering, and their properties are experimentally evaluated.

null

['Kulkarni, N.P.', 'Sparks, T.E.', 'Tandra, G.', 'Liou, F.W.']

2021-10-01T00:01:15Z

2010

Mechanical Engineering

null

['https://hdl.handle.net/2152/88301', 'http://dx.doi.org/10.26153/tsw/15242']

eng

2010 International Solid Freeform Fabrication Symposium

Open

['fuel cell', 'Membrane Electrode Assembly', 'polymer-electrode membrane', 'selective deposition', 'catalyst', 'cost reduction']

MEA Manufacturing Using an Additive Manufacturing Process to Deposit a Catalyst Patter in an MEA and its Impact on Cost Reduction

Conference paper

https://repositories.lib.utexas.edu//bitstreams/337fbed3-92b0-4970-842d-4c2069a18d3f/download

University of Texas at Austin

The manufacturing of a fuel cell Membrane Electrode Assembly (MEA) is a significant cost driver in polymer-electrolyte membrane (PEM) fuel cell technologies, primarily due to the inclusion of expensive materials in the catalyst layer. The selective deposition of a catalyst on the MEA of a fuel cell can drastically reduce the costs depending upon the catalyst, method used for deposition, and production volume. In this paper, testing and analysis of a novel catalyst iridium oxide is discussed. The performance of the catalyst will be compared with the conventional catalysts which will give us an estimate of its effectiveness however, in this paper, only its feasibility in terms of cost is discussed.

null

['Chalancon, Antoine', 'Bourell, David']

2021-11-01T21:47:14Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89767

eng

2016 International Solid Freeform Fabrication Symposium

Open

['energy density', 'polyamide 12', 'laser sintering']

Measured Energy Densities for Polyamide 12 and Comparison of Values Calculated for Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9edc7ece-f767-457b-a8cc-25c1c4a2da87/download

University of Texas at Austin

Energy density is a key factor in the Laser Sintering (LS) process, and impacts the properties of the built parts. Processing parameters have an important effect on Laser Sintering. This paper focuses on the evaluation of various energy density equations. Experiments were carried out by varying processing parameters, namely, laser power, scan speed, hatch distance/scan spacing and layer thickness to change actual and calculated energy density. Relative density was estimated using the Archimedes method and mensuration. As a result, a correlation between the laser energy density and the relative density has been established. Finally, the effect of parameters is discussed.

null

['Dvorak, Jake', 'Ajinjeru, Christine', 'Smith, Tyler', 'Kim, Seokpum', 'Hershey, Christopher', 'Lindahl, John', 'Kunc, Vlastimil', 'Duty, Chad']

2021-11-18T17:22:15Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90435', 'http://dx.doi.org/10.26153/tsw/17356']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['pressure profiles', 'pressure distributions', 'single screw extruder', 'big area additive manufacturing', 'BAAM']

Measurement and Analysis of Pressure Profile Within Big Area Additive Manufacturing Single Screw Extruder

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e09c94ca-4713-4a64-833a-d434c0115c39/download

University of Texas at Austin

Pressure distributions within a single screw extruder are dependent on several factors, namely, processing parameters and flow geometry. The Big Area Additive Manufacturing (BAAM) system involves a complex flow geometry with multiple flow zones following the screw extruder. This study utilized experimental data and a one-dimensional (1-D) analytical model to compare pressures at specific areas of interest in the BAAM system. Initial results show a need for further two-dimensional (2-D) and three-dimensional (3-D) simulation and modeling of the BAAM extruder with more accurate underlying assumptions. The results of this work will allow for further study of BAAM input parameters for optimal print quality, material properties, and print head geometric design.

null

['Klingbeil, N.W.', 'Beuth, J.L.', 'Chin, R.K.', 'Amon, C.H.']

2019-02-22T20:05:09Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73471', 'http://dx.doi.org/10.26153/tsw/621']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['SFF', 'SDM']

Measurement and Modeling of Residual Stress-Induced Warping in Direct Metal Deposition Processes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c0cbd1ff-4247-4d8d-98c1-fb2becbe36dc/download

null

Tolerance loss due to residual stress-induced warping is a major concern in solid freeform fabrication (SFF) processes. An understanding of how residual stresses develop and how they lead to tolerance loss is a key issue in advancing these processes. In this paper, results are presented from warping experiments on plate-shaped specimens created by microcasting and welding processes used in Shape Deposition Manufacturing (SDM). Results from these experiments give insight into differences between the two processes, the role of preheating and insulating conditions during manufacture and the influence of deposition path on magnitudes and distributions of warping displacements. Results are then compared to predictions from two types of residual stress models. While the models effectively predict warping magnitudes and the effects of various thermal conditions, they are unable to capture some of the more subtle trends in the experiments. Results from the experiments and numerical models suggest that a combination of initial substrate preheating and part insulation can be applied to SDM and similar SFF processes to limit warping deflections, which is substantially simpler than active control of part temperatures during manufacture. Results also suggest that 3-D mechanical constraints are important in achieving precise control of warping behavior in SFF processes.

null

['Sumin Sih, Samuel', 'Barlow, Joe W.']

2018-10-03T16:50:51Z

1994

Mechanical Engineering

doi:10.15781/T2KH0FJ02

http://hdl.handle.net/2152/68665

eng

1994 International Solid Freeform Fabrication Symposium

Open

['selective laser sintering', 'hydroxyapatite powder', 'thermal conductivity of power beds']

Measurement and Prediction of the Thermal Conductivity of Powders at High Temperatures

Conference paper

https://repositories.lib.utexas.edu//bitstreams/18e41ece-472c-4262-9850-c16bc182e09e/download

null

An equation for the prediction of the thermal conductivity of powder beds up to high temperatures is suggested by the authors. The predicted values by the equation are compared with the values of the thermal conductivity of alumina powder, magnesia powder and zirconia powder reported in the literature, and are found to be consistent. The predicted values by the equation are also compared with the measured values of the thermal conductivity of calcium hydroxyapatite powder, at various temPeratures, up to 500°C by the laser-heated method.

null

['Klingbeil, N.W.', 'Zinn, J.W.', 'Beuth, J.L.']

2018-11-28T21:25:24Z

1997

Mechanical Engineering

doi:10.15781/T25X25Z66

http://hdl.handle.net/2152/70332

eng

1997 International Solid Freeform Fabrication Symposium

Open

['SDM process', 'Microcasting']

Measurement of Residual Stresses in Parts Created by Shape Deposition Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/fc99ca1b-ed6f-43cc-81fd-fa5c9fc571c5/download

null

Residual stress build-up is a concern in any solid freeform fabrication process involving successive deposition of uncured or molten material, due to differential contractions caused by solidification or curing. The most detrimental effect of residual stresses is typically part warping, which can lead to unacceptable losses in part tolerance. In many processes residual stress build-up is a fundamental barrier to the consistent manufacture of high-quality artifacts. In this paper, two methods of measuring residual stresses in parts created by Shape Deposition Manufacturing (SDM) with microcasting are described. First, a technique for measuring warping in deposited plateshaped specimens is detailed, which can be used to determine residual stress resultants as well as to quantify gross effects of processing changes on residual stress magnitudes. Next, x-ray diffraction procedures are described by which residual stresses in deposited layers can be measured at discrete in-plane locations as a function of depth. Measured results for 308L stainless steel deposits determined from each method are interpreted in the context of residual stress modeling results obtained numerically in a separate research effort. The measured results provide insight into the effects on residual stress of both the material deposition path and the discrete droplet-bydroplet nature of the microcasting deposition process. The insights provided here may also be applicable to other processes involving successive material deposition.

null

['Steinberger, J.', 'Manetsberger, K.', 'Shen, J.', 'MulIers, J.']

2019-03-13T16:18:15Z

1999

Mechanical Engineering

null

['https://hdl.handle.net/2152/73640', 'http://dx.doi.org/10.26153/tsw/782']

eng

1999 International Solid Freeform Fabrication Symposium

Open

['SLS', 'electromagnetic']

Measurement of the Sintering Dynamics of polymeric powders at Near SLS Conditions

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2d4f5048-b14d-469d-b508-755734177604/download

null

The sintering dynamics of materials used in the Selective Laser Sintering process impact greatly the thermal conditions of the powder bed. An experimental setup was developed to obtain sintering rate information at conditions very near to those of the SLS process. The system consists of a powder sample heated by a CO2 laser while maintained at constant thermal boundary conditions. The powder height is measured by means of an optical sensor, which avoids stress on the powder and allows fast data. acquisition. This paper discusses experiments conducted with this apparatus and further compares the obtained results with theoretical models and the previous work of others.

null

['Sih, Samuel S.', 'Barlow, Joel W.']

2018-05-03T20:04:24Z

1993

Mechanical Engineering

doi:10.15781/T2BG2HT54

http://hdl.handle.net/2152/65081

eng

1993 International Solid Freeform Fabrication Symposium

Open

['Chemical Engineering Department', 'sintering', 'laser-heat', 'thermal']

Measurement of the Thermal Conductivity of Powders by Two Different Methods

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6e2a9f46-5368-410f-b34a-d909d1029617/download

null

The thermal diffusivities and thermal conductivities of powders, especially PMMA-coated silicon carbide, at various temperatures, have been tested by two different dynamic methods, the water-bath method and the laser-heated method. The thermal conductivity data found by these two techniques are found to be consistent with each other.

null

['Sih, Samuel S.', 'Barlow, Joel W.']

2018-04-19T17:25:44Z

1991

Mechanical Engineering

doi:10.15781/T2JS9HR3W

http://hdl.handle.net/2152/64389

eng

1992 International Solid Freeform Fabrication Symposium

Open

['Chemical Engineering Department', 'polymer powders', 'SLS']

The Measurement of the Thermal Properties and Absorptances of Powders Near their Melting Temperatures

Conference paper

https://repositories.lib.utexas.edu//bitstreams/0f75d6fe-d37e-473f-9e1f-5e1e9841dca4/download

null

A new technique, using a laser as the heating source, has been adopted to measure the heat capacities, thermal diffusivities, thermal conductivities, and absorptances of powders (especially polymer powders) near their melting temperatures. This makes use of an unsteady state process. The data of the thermal conductivities obtained through this technique below 100°C are in concord with the values obtained through the other techniques, which predicts well for the use of this technique for still higher temperatures, up to the melting temperatures of the powders to be investigated.

null

['Fly, David E.', 'Gradowski, Anita', 'Espalin, David', 'Winker, Rob', 'Rask, Josh']

2021-10-18T20:24:48Z

2014

Mechanical Engineering

null

https://hdl.handle.net/2152/89233

eng

2014 International Solid Freeform Fabrication Symposium

Open

['CMM', 'gauge blocks', 'gauge pins', 'calipers', 'FDM', '3D printing', '3D scanning', 'error compensation', 'sources of variation']

Measurement Systems Comparison on Various Feature Sizes of FDM Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/cd22a743-7b1b-4e9d-aeae-90cbeef26dff/download

University of Texas at Austin

12 identical FDM parts were produced in ABSM30, each having 16 features for replicated measurements. Half the features were positive (posts), half were negative (holes). Half of all features were rectangular, half were round. Two different CMMs with 1.5mm touch probes were compared, one CMM additionally used a laser, and manual measurements were taken with gauges and calipers. All features were measured using these 4 measurement systems. All measurements were compared against the theoretical feature size to generate a percent error value. The laser values were notably different than both probe values. The manual measurements were similar to one of the two CMM probes. Positive versus negative features were significantly different in 7 of 8 cases. Feature size and measurement error were inversely proportional. The largest features had the least amount of error in all cases while the features below 6mm had the most error and high variation.

null

['Fodran, Eric', 'Koch, Martin', 'Menon, Unny']

2018-11-14T20:58:25Z

1996

Mechanical Engineering

doi:10.15781/T20V8B325

http://hdl.handle.net/2152/70266

eng

1996 International Solid Freeform Fabrication Symposium

Open

['FDM', 'mechanical properties', 'polymer materials']

Mechanical and Dimensional Characteristics of Fused Deposition Modeling Build Styles

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b21f67dd-9ccc-4c33-8fb0-a03e3576b30a/download

null

As rapid prototyping becomes more prominent, industry relies more on the mechanical properties of the builds. Fused Deposition Modeling (FDM) tensile samples were constructed and tested in order to characterize the mechanical properties of Acrylonitrile Butadiene Styrene (ABS) FDM builds. Parameters such as fill gap, line width, and slice thickness were varied in the production of the FDM samples. This was performed independently to isolate the effect of each parameter on mechanical properties. Results include the ultimate tensile strength, yield strength, elongation, energy to fracture, modulus of elasticity, and dimensional analysis. High magnification fracture surface analysis was also be performed to aid in the characterization of sample failures.

null

['Rüsenberg, S.', 'Schimdt, L.', 'Schmid, H.-J.']

2021-10-04T21:28:03Z

8/17/11

Mechanical Engineering

null

['https://hdl.handle.net/2152/88352', 'http://dx.doi.org/10.26153/tsw/15291']

eng

2011 International Solid Freeform Fabrication Symposium

Open

['physical properties', 'mechanical properties', 'laser sintered parts', 'polyamide parts']

Mechanical and Physical Properties - A Way to Assess Quality of Laser Sintered Parts

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a614c87e-dce4-44cc-a0f9-52fee509c73a/download

University of Texas at Austin

The aim of this paper is the description and evaluation of physical properties like porosity and density and their influence on mechanical properties of laser sintered polyamide parts. For example, by reducing the porosity an increase of mechanical properties is possible. The correlation of laser parameters to these properties is investigated in detail. The energy density is an important parameter for the laser sintering process. By changing laser power, scan velocity and hatch distance an influence on manufactured components is given. A systematic variation of all three laser parameters is performed. A comparison of results obtained at constant energy densities obtained by varying these relevant parameters accordingly is shown as well.

null

['Venkataraman, N.', 'Rangarajan, S.', 'Matthewson, M.J.', 'Safari, A.', 'Danforth, S.C.', 'Yardimci, A.', 'Guceri, S.I.']

2019-03-15T15:49:49Z

1999

Mechanical Engineering

null

['https://hdl.handle.net/2152/73685', 'http://dx.doi.org/10.26153/tsw/827']

eng

1999 International Solid Freeform Fabrication Symposium

Open

['Fused deposition of ceramics', 'solid freeform']

Mechanical and Rheological Properties of Feedstock Material for Fused Deposition of Ceramics and Metals (FDC and FDMet) and their Relationship to Process Performance

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1910680e-5974-4d56-9fd4-8d86904537e7/download

null

Fused deposition of ceramics (FDC) is a solid freeform fabrication technique based on extrusion of a highly loaded thermoplastic binder system. The present FDC process uses filament feedstock of 1.780 mm ± 0.025 mm diameter. The.filament acts as both the piston driving the extrusion process as well as the molten feedstockbeing deposited. The filaments need to be able to provide and sustain the pressure needed to drive the extrusion process. Failure to do this results in failure via "buckling". The filament compressive modulus determines the ability ofthe filament to provide·and sustain the required pressure to drive the extrusion. The viscosity ofthe feedstock material, nozzle geometry and volumetric flow rates employed determine the pressure needed to drive the extrusion process. In this worktheiextrusion pressure for a particular material termed PZT ECG9 (52.6 Vol.% PZT powder in ECG9i~inder) was measured experimentally as a function of volumetric flow rate and nozzle geometry.rhe compressive modulus ofthe material was determined using a miniature materials tester (Rheoinetrics, Inc., Piscataway, NJ). A process map has been developed. The map is based .on the quantity MIE, and predicts the performance of the material in a FDC process as a.functioIl.ofnozzleg~ometry and volumetric flow rate. In general, it is observed that when MIE exceeds a critical value, called APcr/E, there is an increased tendency for the filament to buckle. A. preliminary fluid flow model for extrusion of PZT ECG9 through a FDC nozzle has also been developed using Polyflow™ software. The model predicts the observed trend in pressure drop with flow rate and nozzle geometry with reasonable accuracy.

null

['Knoop, F.', 'Schoeppner, V.']

2021-10-21T15:13:54Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89391

eng

2015 International Solid Freeform Fabrication Symposium

Open

['Fused Deposition Modeling', 'polyamide 12', 'mechanical properties', 'thermal properties']

Mechanical and Thermal Properties of FDM Parts Manufactured with Polyamide 12

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5e34de4f-e770-4211-8b49-2535ecfa293f/download

University of Texas at Austin

Fused Deposition Modeling (FDM) is an Additive Manufacturing (AM) technology which is used for prototypes, single-part production and also small batch productions. For use as a final product, it is important that the parts have good mechanical properties, high dimensional accuracy and smooth surfaces. The knowledge of the mechanical properties is very important for the design engineer when it comes to the component design. End-use products out of the FDM process have to resist applied forces. In this paper, investigations were conducted with the polymer Polyamide 12 (FDM Nylon 12) from Stratasys Inc. This polymer can be processed with three different tip sizes resulting in different layer thicknesses from 178 μm to 330 μm. Thus, the mechanical properties were determined for these layer thicknesses and for different orientations on the build platform. In addition to the mechanical properties the thermal properties (e.g. with a DSC analysis) are also investigated.

null

['Davies, S.J.', 'Jeffs, S.P.', 'Lancaster, R.J.', 'Baxter, G.']

2021-11-02T14:14:39Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89810

eng

2017 International Solid Freeform Fabrication Symposium

Open

['small punch tensile test', 'nickel superalloy', 'laser powder bed fusion', 'LPBF', 'build orientation', 'heat treatment']

Mechanical Assessment of a LPBF Nickel Superalloy Using the Small Punch Test Method

Conference paper

https://repositories.lib.utexas.edu//bitstreams/22c632bd-dfaf-45bc-8a0e-6616b952d30a/download

University of Texas at Austin

With the continuous drive of the aerospace industry to introduce Additive Layer Manufacturing (ALM) into next generation gas turbine engines, the requirement to understand their mechanical performance has grown. However, limitations in material availability due to the nature of the process can restrict the scope for conventional mechanical testing. The Small Punch Tensile (SPT) test provides an effective tool for ranking the performance of ALM processed alloys, credited to the small volumes of material utilised and the ability to sample localised regions. This technique has been applied to the nickel superalloy C263, manufactured via Laser Powder Bed Fusion (LPBF) in different build orientations and subjected to contrasting post process heat treatments. To fully understand the effects of these process variables on the mechanical response of LPBF alloys, empirical correlations have been derived between SPT and uniaxial data attempting to demonstrate the suitability of this approach in characterising the properties of ALM structures.

null

['Guivier, Manon', 'Kuebler, Jesse', 'Swanson, Trevor', 'Lawson, Christopher', 'Fernandez-Ballester, Lucia', 'Negahban, Mehrdad', 'Sealy, Michael P.']

2021-12-07T18:45:32Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90754', 'http://dx.doi.org/10.26153/tsw/17673']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['hybrid additive manufacturing', 'fused filament fabrication', 'polymer', 'ultrasonic peening']

Mechanical Behavior of ABS after Interlayer Ultrasonic Peening Printed by Fused Filament Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a357eba2-dd85-4068-bb9b-e29adc3e0c6b/download

University of Texas at Austin

Hybrid additive manufacturing brought new opportunities to improve the mechanical properties of materials by secondary processing of individual layers during printing. Previous work demonstrated interlayer shot peening during printing by fused filament fabrication (FFF) affected mechanical behavior while inadvertently imparting debris contamination from pulverized beads. The encouraging results motivated a study on the use of contamination free ultrasonic peening (UP) as an alternative interlayer surface treatment. Ultrasonic peening of FFF printed Acrylonitrile Butadiene Styrene (ABS) was studied in order to compare the effects on mechanical properties between ultrasonic peening and previously studied shot peening, different print orientations, and different interlayer peening frequencies. Two different layer peening frequencies (L4 and L8) were compared to an as-printed control (L0). Two orientations for each layer peening frequency were chosen for comparison. Tensile tests were conducted in order to observe the influence of interlayer UP on tensile strength of ABS parts.

null

['Shrestha, Rakish', 'Sterling, Amanda', 'Lessel, Brandon', 'Phan, Nam', 'Sereshk, Mohammad Reza Vaziri', 'Shamsaei, Nima']

2021-11-09T20:07:50Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90151', 'http://dx.doi.org/10.26153/tsw/17072']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['monotonic tensile test', 'lattice', 'schoen gyroid structure', 'additive manufacturing', '17-4 PH SS']

Mechanical Behavior of Additively Manufactured 17-4 PH Stainless Steel Schoen Gyroid Lattice Structure

Conference paper

https://repositories.lib.utexas.edu//bitstreams/30f4d075-1bd5-45b6-8383-36d1c601d262/download

University of Texas at Austin

In this study, the mechanical properties of additively manufactured 17-4 PH stainless steel Schoen Gyroid lattice structures were investigated under monotonic tensile loading. Based on the results obtained from the monotonic tensile test, relationship between tensile properties and relative density of Schoen Gyroid was also established based on the Gibson-Ashby equations. Four different types of gyroid structures with varying volume fractions were designed by altering thickness and length of the unit cell and then fabricated in horizontal direction using a laser powder bed fusion (L-PBF) process. Monotonic tensile tests were conducted under displacement control mode with the speed of cross head movement set to be equivalent to the strain rate of 0.001 s-1 . Monotonic tensile results showed a decrease in stiffness and a slight increase in elongation to failure with the decreasing volume fraction among different lattice structures. A good correlation between the material properties (maximum force and stiffness) and volume fraction was also obtained using Gibson-Ashby type relationship. Furthermore, maximum force normalized by the volume per unit length was calculated to determine the effect of cell thickness and length on the resulting mechanical properties. Normalized force versus displacement plot illustrated an increase in stiffness with the increase in unit cell thickness. Whereas, lattice structures with similar cell length and cell thickness exhibited similar normalized maximum force as well as stiffness values.

null

['Sereshk, Mohammad Reza Vaziri', 'Shrestha, Rakish', 'Lessel, Brandon', 'Phan, Nam', 'Shamsaei, Nima']

2021-11-30T21:42:03Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90559', 'http://dx.doi.org/10.26153/tsw/17478']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['lattice structures', 'gyroids', 'heat treatment', 'mechanical behavior', 'post-processing', 'laser beam powder bed fusion']

Mechanical Behavior of Additively-Manufactured Gyroid Lattice Structure under Different Heat Treatments

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3f8757c6-fefb-4e77-a6d2-978e0fca58c3/download

University of Texas at Austin

Gyroid lattice structures, known for high stiffness and specific strength, are gaining attention for their energy absorption ability. However, energy absorption and strength of the gyroids are two desired properties, which vary contradictory. This study investigates manipulating properties on lattices using post-processing operation instead of modifying dimensions with consequent changes in weight and production cost. The challenge is that a particular post-processing heat treatment may improve one property, while it may be detrimental to other ones. The compressive properties of 17-4 PH stainless steel gyroid lattice structures fabricated using laser beam powder bed fusion (LB-PBF) method is investigated. Compressive properties such as load bearing capacity, crashing strength, and energy absorption are determined and the trends in their variation are discussed. Based on the experimental results, heat treating lattices with CA H900 procedure improves energy absorption and strength considerably, while increases crashing force, as well.

null

['Wang, Mei', 'Zhou, Yan', 'Wei, Q.S.', 'Fan, Zhunfeng']

2021-11-10T22:50:00Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90198', 'http://dx.doi.org/10.26153/tsw/17119']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['AISI H13', 'hot-work', 'tool steel', 'tensile stress', 'mechanical behavior', 'selective laser melting']

The Mechanical Behavior of AISI H13 Hot-Work Tool Steel Processed by Selective Laser Melting under Tensile Stress

Conference paper

https://repositories.lib.utexas.edu//bitstreams/40654d69-2e18-4209-a70e-9ad2ec5799c2/download

University of Texas at Austin

AISI H13 tool steel is commonly used in hot-working applications include die casting dies, inserts, forging dies, extrusion dies, etc. Molds fabricated by selective laser melting (SLM) with conforming cooling channels can maintain a steady and uniform cooling performance to the molding parts, which ensures high quality of the products and general reduction of the cycle time. Therefore, SLM process has gained increasing attention in the hot-work tool field. The present study concerns the properties of H13 materials that with and without preheating during the SLM process. X-ray diffraction (XRD), field emission scanning electron microscope (SEM), and high-temperature tensile tests were applied to investigate the phases, microstructures and resultant mechanical properties of SLM processed H13. Results show that the application of preheating during SLM process results in a more homogeneous microstructure of the material with better mechanical properties compared to those without preheating. High-temperature tensile strength increased from 1066 MPa to 1183 MPa, the total elongation increased from 5.7% to 8.1%. The high-temperature tensile strength of those parts with preheating was higher than those of the treated commercial H13 tool steel, while the total elongation was much lower than those commercial materials.

null

['Jiang, D.', 'Smith, D.E.']

2021-10-27T22:54:53Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89640

eng

2016 International Solid Freeform Fabrication Symposium

Open

['fused filament fabrication', 'carbon fiber', 'mechanical behavior']

Mechanical Behavior of Carbon Fiber Composites Produced with Fused Filament Fabrication

Conference paper

https://repositories.lib.utexas.edu//bitstreams/be8b30df-5bac-4f49-8386-0d29e97ba227/download

University of Texas at Austin

Fused Filament Fabrication (FFF) is a commonly used Additive Manufacturing (AM) technique. However, the printed parts often lack sufficient mechanical integrity. Recently, mechanical properties of FFF filament have been enhanced by blending pure polymer with short carbon fibers. This paper presents a study of the mechanical properties for carbon fiber filled (CFF) FFF parts produced with Makerbot printers. Polymer composite and pure polymer tensile test coupons are printed and then tested following ASTM D3039M. Here we consider FFF print orientations that are aligned with the test bar axis at 0 degree, 45 degrees, ±45 degrees, and normal to the bar axis at 90 degrees. The filament considered here was purchased from filament suppliers and included PLA, ABS, and PETG. Results are presented for tensile strength and tensile modulus. Additionally, short fiber composite samples are evaluated for fiber length distribution (FLD) and fiber weight fraction. Fracture surfaces are evaluated under SEM.

null

['Denham, Hugh B.', 'Cesarano III, Joseph', 'King, Bruce H.', 'Calvert, Paul']

2019-02-26T20:49:31Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73500', 'http://dx.doi.org/10.26153/tsw/650']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['ceramic', 'strength']

Mechanical Behavior of Robocast Alumina

Conference paper

https://repositories.lib.utexas.edu//bitstreams/95deb3e9-8efd-4ef3-8628-c9ae2919dcd0/download

null

Direct fabrication of alumina parts by robocasting was completed. This method is based on three-dimensional deposition of binderless aqueous alumina slurries. Parts were made with different deposition paths and mechanical·testing performed·to determine the effects •of bead alignment. Properties were also compared to. alumina processed more traditionally

null

['Amado-Becker, Felipe', 'Díaz, Richard A.', 'Ramos-Grez, Jorge']

2020-03-05T20:06:16Z

2006

Mechanical Engineering

null

['https://hdl.handle.net/2152/80154', 'http://dx.doi.org/10.26153/tsw/7175']

eng

2006 International Solid Freeform Fabrication Symposium

Open

Selective Laser Sintering

Mechanical Behavior of SLS Components in Relation to the Build Orientation During the Sintering Process as Measured by ESPI

Conference paper

https://repositories.lib.utexas.edu//bitstreams/afb3e679-633c-4a3a-af66-56b43f2b0f8f/download

null

Selective Laser Sintering (SLS) allows producing real parts from CAD data from materials with different characteristics compared to the final model, presenting dissimilar mechanical properties between the prototype and the product. The purpose of this work is to correlate the mechanical behavior of beam-type specimens produced by SLS with build orientation angle used as a process parameter, also attempting to demonstrate how this parameter affects the accuracy of the Empirical Similitude Method (ESM). ESM presents itself as a valuable tool when creating scale models with SLS, specifically in the framework of evolutionary product design. More specifically, the Young modulus variation of test specimens of well-known dimensions and material (DuraformTM PA2 ), will be characterized by loading them within the elastic range. The resulting elastic deformations will be measured using the technique of Electronic Speckle Pattern Interferometry (ESPI) for small deformations in an out-of-plane configuration, contrasting these results with the elastic theory of deformations. As a main result, it was found that there exists a linear correlation between the build angle and the elastic modulus of the parts. Secondly, it was demonstrated empirically that the ESM predicts better the mechanical response of the part than TSM. Moreover, a 30% error reduction can be achieved within the ESM when using the build orientation angle as a process parameter.

null

['Roach, M.A.', 'Keicher, D.', 'Maines, E.', 'Wall, B.', 'Wall, C.', 'Lavin, J.', 'Whetten, S.', 'Evans, L.']

2021-11-10T21:18:28Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90178', 'http://dx.doi.org/10.26153/tsw/17099']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['ceramics', 'alumina', 'mechanical challenges', '3D printing', 'digital light processing', 'stereolithography']

Mechanical Challenges of 3D Printing Ceramics Using Digital Light Processing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c54b3e1b-f474-444e-b873-c8148675400b/download

University of Texas at Austin

Digital light processing (DLP) 3D printing can be used for manufacturing complex structures using a variety of materials, which would be nearly impossible using traditional manufacturing methods. Recent work at Sandia National Laboratories uses DLP technology for additive manufacturing of complex alumina structures, using photocurable resins loaded with micron or submicron alumina particles. These resins are printed using a DLP 3D printer to produce a “green part.” The work presented here will discuss the mechanical challenges associated with printing alumina using commercially available DLP and stereolithography 3D printers, including the design of a custom DLP 3D printer to address identified mechanical challenges, thereby leading to improved print versatility and quality.

null

['Bertoldi, M', 'Yardimci, M', 'Pistor, C. M.', 'Guceri, S. I', 'Sala, G']

2019-02-26T20:20:28Z

1998

Mechanical Engineering

null

['https://hdl.handle.net/2152/73496', 'http://dx.doi.org/10.26153/tsw/646']

eng

1998 International Solid Freeform Fabrication Symposium

Open

['Fused Deposition Modeling', 'polymer-based material']

Mechanical Characterization of Parts Processed via Fused Deposition

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8e6c667b-678c-49f1-bb67-2b1bb5c0a8fd/download

null

The possibility of using materials with better physical and mechanical properties together with the quickly improving capabilities of various processes increasingly make Rapid Prototyping (RP) as a new manufacturing technology for specialty components. In Fused Deposition Modeling (FDM), the build orientation and the toolpath used strongly affect the properties of the part. This study presents the results of experimental work based on mechanical characterization of parts fabricated with fused deposition to determine the stiffness matrix and the thermal expansion coefficients for an equivalent orthotropic material. The results can be directly adapted into computational analysis tools based on classical lamination theory, for part quality and performance prediction. Current investigation focuses on use ofABS material in Stratasys FDM 1650 rapid prototyping equipment.

null

['Correa, Dixon', 'Bostwick, Ken', 'Wilson, Preston S.', 'Haberman, Michael', 'Seepersad, Carolyn Conner']

2021-10-21T19:21:49Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89428

eng

2015 International Solid Freeform Fabrication Symposium

Open

['negative stiffness honeycombs', 'impact', 'impact performance', 'additive manufacturing']

Mechanical Impact Performance of Additively Manufactured Negative Stiffness Honeycombs

Conference paper

https://repositories.lib.utexas.edu//bitstreams/13044470-bbae-4a04-8fb8-03b4d887d6cd/download

University of Texas at Austin

Negative stiffness honeycombs materials are comprised of negative stiffness beams arranged in ordered arrays. They are capable of providing isolation from impacts and returning to their initial shape. Previous research by the authors focused on the behavior of negative stiffness honeycombs to quasi-static loading conditions. This paper investigates the behavior of similar negative stiffness honeycombs under impact. The construction of an impact testing rig for the experimental evaluation of negative stiffness honeycombs is discussed. Experimental results from impact tests performed on honeycomb prototypes manufactured using selective laser sintering (SLS) in nylon 11 material are presented and compared with analytical and finite element predictions as well as quasi-static test results.

null

['Weflen, E.D.', 'Ginther, M.C.', 'Eldakroury, M.A.', 'Frank, M.C.']

2021-12-07T18:57:26Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90757', 'http://dx.doi.org/10.26153/tsw/17676']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['iterative processing', 'mechanical interface', 'hybrid additive manufacturing', 'hybrid subtractive manufacturing']

Mechanical Interface for Iterative Hybrid Additive and Subtractive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a4286668-3b59-4c24-976c-7b7b51b91ac7/download

University of Texas at Austin

Additive and subtractive manufacturing systems for in-envelope production of large objects face challenges with respect to reach and access of cutting tools. One approach to overcoming this is iteratively alternate between additive and subtractive processes. However, polymer objects require cooling before machining, resulting in poor thermal welding when the subsequent polymer layer is deposited. This paper describes a method to enable iterative processing for in-envelope hybrid manufacturing that uses a mechanical bond to transition back to additive deposition after machining. This is accomplished using an AMBIT screw-extrusion head to additively manufacture a section of the object within a 5-axis machining center. After the object is machined, a dovetail cutting tool forms undercut geometry in the interface where plastic extrusion will resume. Upon polymer solidification, a mechanical interlock is formed. This work evaluates several undercut geometries for mechanical performance. This iterative approach to hybrid additive/subtractive manufacturing reduces machining complexity while maintaining structural integrity.

null

['Benedetti, L.', 'Brulé, B.', 'Decraemer, N.', 'Davies, R.', 'Evans, K.', 'Ghita, O.']

2021-11-18T01:19:06Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90389', 'http://dx.doi.org/10.26153/tsw/17310']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['high temperature laser sintering', 'PEKK', 'mechanical performance']

Mechanical Performance of Laser Sintered Poly(ether Ketone Ketone) (PEKK)

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d556d781-f86a-40fe-b725-5d0194193da5/download

University of Texas at Austin

The recent progress in Additive Manufacturing Powder Bed Fusion systems are bound to attract uptake of new high performance materials. Within the Poly(aryl ether ketone) (PAEK) family, Poly(ether ketone ketone) (PEKK) shows promising mechanical properties, comparable with the commercial laser sintering grade PEK HP3, whilst processed at significantly lower temperatures. Kepstan 6002 PEKK specimens were laser sintered in multiple orientations and a range of mechanical tests were used to assess overall performance. PEKK showed outstanding ultimate tensile strength ranging between 75 and 90 MPa in x-y direction whilst maintaining an elongation at break of 2.6%. Further investigation of the fracture showed localized plastic regions attributed to a better performance. The same plastic behaviour is observed during compression, in which PEKK showed remarkable deformation with no signs of breaking. The combination of properties offered by Kepstan PEKK parts manufactured at a lower processing temperature makes it a very attractive polymer for applications in the aerospace and automotive sectors.

null

['Ponnusamy, P.', 'Masood, S.H.', 'Ruan, D.', 'Palanisamy, S.', 'Rahman Rashid, R.A.', 'Ahmed Mohamed, Omar']

2021-11-02T15:11:09Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89824

eng

2017 International Solid Freeform Fabrication Symposium

Open

['selective laser melting', '17-4 PH', 'quasi-static compression', 'microhardness', 'factorial design']

Mechanical Performance of Selective Laser Melted 17-4 PH Stainless Steel Under Compressive Loading

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6f67acfb-8547-45d3-a451-4c11a6c98226/download

University of Texas at Austin

Selective Laser Melting (SLM) is a powder-bed type Additive Manufacturing (AM) process, where metal powder melting is followed by rapid solidification to yield metallic components. The mechanical performance of the components is greatly influenced by various SLM process parameters such as laser power, scan speed, scan pattern, hatch distance, build orientation, layer thickness and defocus distance. Studies on compressive properties of stainless steel parts by SLM have received relatively little attention. In this study, an investigation was conducted to assess the influence of laser power, build orientation, layer thickness and laser defocus distance on the mechanical behaviour of selective laser melted 17-4 PH stainless steel parts under quasi-static compression. Fractional factorial design was used to optimise the four process parameters to obtain maximum hardness and compressive strength with least porosity. Results are supported by studies on porosity and microstructure observations.

null

['Bens, A. T.', 'Tille, C.', 'Leukers, B.', 'Bermes, G.', 'Emons, M.', 'Sobe, R.', 'Pansky, A.', 'Roitzheim, B.', 'Schulze, M.', 'Tobiasch, E.', 'Seitz, H.']

2020-02-20T21:04:38Z

8/25/05

Mechanical Engineering

null

https://hdl.handle.net/2152/80054

eng

2005 International Solid Freeform Fabrication Symposium

Open

stereolithography

Mechanical Properties and Bioanalytical Characterization for a Novel Non-Toxic Flexible Photopolymer Formulation Class

Conference paper

https://repositories.lib.utexas.edu//bitstreams/7701583d-70fc-4987-86c6-99aab3cc2509/download

null

We present herein a new class of resin formulations for stereolithography, named FlexSL, with a broad bandwidth of tunable mechanical properties. The novel polyether(meth)acrylate based material class has outstanding material characteristics in combination with the advantages of being a biocompatible (meth)acrylate based processing material. FlexSL shows very promising results in several initial biocompatibility tests. This emphasizes its non-toxic behavior in a biomedical environment, caused mainly by the (meth)acrylate based core components. The FlexSL materials are less cytotoxic than other commercial available and tested resin materials. This novel resin material could then be one of the engineering materials of choice for very complex three-dimensional structures in the medical technologies area. A short overview of mechanical and processing properties will be given in the end.

null

['Dalgarno, K. W.', 'Wood, D. J.', 'Goodridge, R. D.', 'Xiao, K.', 'Ohtsuki, C.', 'Genever, P.', 'Dyson, J.']

2020-02-20T20:44:01Z

8/25/05

Mechanical Engineering

null

https://hdl.handle.net/2152/80051

eng

2005 International Solid Freeform Fabrication Symposium

Open

['apatite-mullite', 'apatite-wollostonite']

Mechanical Properties and Biological Responses of Bioactive Glass Ceramics Processed using Indirect SLS

Conference paper

https://repositories.lib.utexas.edu//bitstreams/df654d2f-6258-404a-bfa9-1e12660c1e3f/download

null

This paper will report on research which aims to generate bone replacement components by processing bioactive glass-ceramic powders using indirect selective laser sintering. The indirect SLS route has been chosen as it offers the ability to tailor the shape of the implant to the implantation site, and two bioactive glass ceramic materials have been processed through this route: apatite-mullite and apatite-wollostanite. The results of bend tests, to investigate mechanical properties, and in vitro and in vivo experiments to investigate biological responses of the materials will be reported, and the suitability of completed components for implant will be assessed.

null

['Obielodan, J.', 'Delwiche, M.']

2023-03-29T16:25:53Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117680', 'http://dx.doi.org/10.26153/tsw/44559']

eng

2022 International Solid Freeform Fabrication Symposium

Open

laser sintering

Mechanical Properties Characterization for Polyamide Matrix Dairy Protein Composites Fabricated Using Selective Laser Sintering Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f84ce460-5358-4190-85dd-d15a5b125de5/download

null

This work investigates the viability of casein protein for manufacturing engineering structures. Polyamide 12 (PA12) was used as a matrix for different compositions of casein up to 20 wt%. Test samples were fabricated for neat PA12 and the composites using selective laser sintering for mechanical properties comparisons. The results show significant increases of the tensile strengths up to 71% for the composite materials over the neat PA12. Stiffnesses also increased up to 157%. The composite samples were embrittled in comparison with the neat PA12 samples, however, with the addition of a plasticizer, significant improvement in ductility was obtained from near 2% to over 6% percent elongation with marginal loss in strength. The investigation shows the dependencies of mechanical properties of the composites on the type of filler casein and treatments.

null

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

2021-11-09T15:32:58Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90096', 'http://dx.doi.org/10.26153/tsw/17017']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['Ti-6Al-4V', 'thin-wall structure', 'laser metal deposition', 'CNC milling', 'hybrid manufacturing', 'design of experiment']

Mechanical Properties Evaluation of a Ti-6Al-4V Thin-Wall Structure Produced by a Hybrid Manufacturing Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/076a2a45-d15a-40a8-9648-6e2a33e3dc84/download

University of Texas at Austin

The hybrid manufacturing (HM) process combines the precision of computer numerical control (CNC) and the freeform capability of additive manufacturing to expand the versatility of advanced manufacturing. The intent of this paper is to explore the relationship between HM processing parameters and mechanical properties of the final parts manufactured by one type of HM process that combines laser metal deposition (LMD) and CNC milling. The design of experiment (DOE) is implemented to explore the Ti-6Al-4V thin-wall structure fabrication process with different HM build strategies. Vickers hardness, tensile test, and microstructure analyses are conducted to evaluate the mechanical property variance within the final parts fabricated according to the DOE matrix. Finally, a prediction model of yield strength at 0.2% offset for Ti-6Al-4V parts built through the aforementioned HM process was obtained by an analysis of variance (ANOVA) test, which revealed the significant factors are build height within each LMD process, laser energy input, and the interaction of build height within each LMD process to the preheating condition.

null

['Hung, Chia-Hung', 'Shen, Yiyu', 'Leu, Ming', 'Tsai, Hai-Lung']

2021-11-04T15:33:21Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/89987', 'http://dx.doi.org/10.26153/tsw/16908']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['mechanical property', '304L stainless steel', '304L', 'laser-foil-printing']

Mechanical Properties of 304L Metal Parts Made by Laser-Foil-Printing Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9c28d9b8-fbfe-44df-85ab-22f176e0b19a/download

University of Texas at Austin

Laser-Foil-Printing (LFP) is a novel laminated object manufacturing process for metal additive manufacturing. It fabricates three-dimensional metal parts by using a dual-laser system to weld and cut metal foils layer by layer. A main advantage of LFP is the higher cooling rate compared to powder-based laser additive manufacturing processes due to the thermal conductivity difference between foil and powder. This study focuses on the mechanical properties of 304L stainless steel parts built by the LFP process. The experimental results indicate that the yield strength and ultimate tensile strength of LFP fabricated 304L SS parts are higher by 9% and 8% in the longitudinal direction, and 24% and 25% in the transverse direction, respectively, in comparison to the parts fabricated by the selective laser melting process. X-ray diffraction and electron backscattered diffraction are used to obtain the lattice structure and the grain size of the fabricated parts.

null

['Pinter, P.', 'Baumann, S.', 'Lohr, C.', 'Heuer, A.', 'Englert, L.', 'Weidenmann, K.A.']

2021-11-15T22:28:41Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90295', 'http://dx.doi.org/10.26153/tsw/17216']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['APF', 'FFF', 'impact properties', 'computed tomography']

Mechanical Properties of Additively Manufactured Polymer Samples using a Piezo Controlled Injection Molding Unit and Fused Filament Fabrication compared with a Conventional Injection Molding Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/84d90199-4e35-498c-8a7d-be66379f3c9d/download

University of Texas at Austin

In polymer additive manufacturing (AM), many processes have been developed and optimized in order to achieve decent mechanical properties in recent years. Nonetheless, it is hardly possible to reach the reference properties given by the injection molding process using the same base material. Within this contribution, a process using a piezo controlled injection molding unit was compared with a common fused filament fabrication (FFF) process and the injection molding process. The novel AM process using an injection molding unit can theoretically process any thermoplastic granulate. In order to compare these three mentioned processes, a filament for the FFF was extruded using the same ABS granulate as for the method based on the piezo controlled injection molding unit and the conventional injection molding process. Results show that quasi-static mechanical properties depend more on the achievable density than on the manufacturing process itself while dynamic tests offer room for optimizations.

null

['Brøtan, V.', 'Fergani, O.', 'Sørby, K.', 'Welo, T.']

2021-11-01T21:10:29Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89753

eng

2016 International Solid Freeform Fabrication Symposium

Open

['strut size', 'stiffness', 'compressive strength', '316L', 'rhombic dodecahedron', 'lattice structures', 'additive manufacturing']

Mechanical Properties of Biocompatible 316L Steel Rhombic Dodecahedron Lattice Structures

Conference paper

https://repositories.lib.utexas.edu//bitstreams/7abce253-fcfc-42fe-932a-cd7d495b06be/download

University of Texas at Austin

Additive manufactured lattice structures have the potential of enhancing many of today’s engineered products manufactured by traditionally methods. The former provides the capability of altering the mechanical, thermal and acoustic properties of structures through the use of lattices. However, more investigation is needed to better understand the manufacturability and the mechanical behavior of sandwich structures. This paper investigates the influence of strut size on the global stiffness and the compressive strength using compression testing of sandwich structures. Digital Image Correlation (DIC) analysis is applied to determine the local strain distribution during the compression test. It is found that the compressive strength increases linearly with increased lattice strut diameter. Moreover, based on DIC the maximum strains are observed in the strut connection regions.

null

['Wang, Zezheng', 'Runzi, Michael', 'Gilchrist, Matthew', 'Gong, Haijun']

2021-12-01T23:27:27Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90655', 'http://dx.doi.org/10.26153/tsw/17574']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['PEEK', 'mechanical properties', 'fused deposition modeling']

Mechanical Properties of High-Performance Plastic Polyether-ether-ketone (PEEK) Printed by Fused Deposition Modeling

Conference paper

https://repositories.lib.utexas.edu//bitstreams/232e7d0e-2db3-481f-a832-c4c6b5da59d7/download

University of Texas at Austin

Polyether-ether-ketone (PEEK) is a high-performance thermoplastic material with high heat resistance, high chemical resistance, high water resistance, and high wear resistance. Due to its distinguished strength and durability, PEEK is extensively used for aerospace, automotive, and medical applications. 3D printing PEEK filaments offer a new approach to make PEEK parts, fulfilling specific requirements of geometrical complexity. But the mechanical properties of 3D printed PEEK materials are not further explored. This study investigated the mechanical properties of PEEK materials fabricated using the fused deposition modeling (FDM) 3D printing process. Tensile test, hardness test, and impact test were conducted to the PEEK samples, in compliance with ASTM standards. The testing results were summarized and discussed, compared to the conventionally manufactured PEEK materials. This study also provides insights on employing FDM 3D printing process for making PEEK parts, based on its special mechanical properties and failure mode.

null

['Bandyopadhyay, Amit', 'Atisivan, Raj', 'Kuhn, Gabe', 'Yeruva, Suresh']

2019-09-18T16:07:37Z

2000

Mechanical Engineering

null

['https://hdl.handle.net/2152/75897', 'http://dx.doi.org/10.26153/tsw/2997']

eng

2000 International Solid Freeform Fabrication Symposium

Open

Alumina-Al

Mechanical Properties of Interconnected Phase Alumina-Al Composites 24

Conference paper

https://repositories.lib.utexas.edu//bitstreams/418b02f4-bff1-454b-af44-819cddeccd03/download

null

Interconnected phase alumina-Al composites were fabricated by pressureless reactive metal infiltration of porous mullite ceramic preforms. Controlled porosity mullite ceramics were processed via the indirect fused deposition. Volume fraction, size and distribution of metals were varied in the composite to understand their effects on physical, thermal and mechanical properties. Mechanical testes were conducted under uniaxial compression and four-point bend loading. Fractographic analyses of these samples were performed to understand the mechanism of failure under different types of loading. The paper describes processing and characterization of structured alumina-Al composites.

Office of Naval Research through the grant N00014-98-1-550 (Program Manager: Dr. Steve Fishman).

null

['Kobryn, P.A.', 'Semiatin, S.L.']

2019-10-10T16:54:21Z

2001

Mechanical Engineering

null

['https://hdl.handle.net/2152/76172', 'http://dx.doi.org/10.26153/tsw/3261']

eng

2001 International Solid Freeform Fabrication Symposium

Open

Laser-Deposited

Mechanical Properties of Laser-Deposited Ti-6Al-4V

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1f223781-6661-4c46-bce0-e2fdafc56f01/download

null

Laser additive manufacturing is a solid-freeform-fabrication process which is being investigated for titanium-component manufacturing and repair based on its cost-reduction potential and flexibility. Laser additive manufacturing also has the potential to improve mechanical properties due to the high cooling rates involved. However, the effect of the layered manufacturing process and any lack-of-fusion porosity and texture on the magnitude and anisotropy of mechanical properties is of concern. Hence, a preliminary effort was undertaken to assess these effects for bulk Ti-6Al-4V deposits manufactured using the LENS™ process. Tension, fatigue, and crack-growth tests were performed on both stress-relieved and HIP’ed deposits in three primary directions. The results were compared to published data for conventionally processed Ti-6Al-4V castings and forgings.

null

['Santos, Edson', 'Abe, F.', 'Kitamura, Y.', 'Osakada, K.', 'Shiomi, M.']

2019-10-23T14:30:23Z

2002

Mechanical Engineering

null

['https://hdl.handle.net/2152/76547', 'http://dx.doi.org/10.26153/tsw/3636']

eng

2002 International Solid Freeform Fabrication Symposium

Open

Titanium

Mechanical Properties of Pure Titanium Models Processed by Selective Laser Melting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/2cd12e5e-560f-4ac6-abfd-fa7436e4b592/download

null

The influence of laser processing parameters on mechanical properties and microstructure of pure titanium models made by selective laser melting is investigated. The density of the models can reach higher than 95% under proper conditions. Although the tensile strength test shows results comparable to the wrought material, the impact and torsional fatigue strengths are low because of porosity and oxygen pick-up suggested by increasing of hardness. Hot isostatic pressing allows almost full densification and greatly improves mechanical properties.

null

['Aboulkhair, Nesma T.', 'Stephens, Alex', 'Maskery, Ian', 'Tuck, Chris', 'Ashcroft, Ian', 'Everitt, Nicola M.']

2021-10-21T15:34:14Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89398

eng

2015 International Solid Freeform Fabrication Symposium

Open

['selective laser melting', 'aluminum alloys', 'AlSi10Mg', 'nanoscale', 'microscale', 'macroscale', 'mechanical properties']

Mechanical Properties of Selective Laser Melted AlSi10Mg: Nano, Micro, and Macro Properties

Conference paper

https://repositories.lib.utexas.edu//bitstreams/4f3cb635-ea27-4afa-b824-b80260674721/download

University of Texas at Austin

The selective laser melting (SLM) of aluminium alloys is of great current interest at both the industrial and research levels. Aluminium poses a challenge to SLM compared with other candidate materials, such as titanium alloys, stainless steels, and nickel-based alloys, because of its high thermal diffusivity and low infrared absorptivity and tendency to result in relatively porous parts. However, recent studies have reported the successful production of dense AlSi10Mg parts using SLM. In this study, we report on the nano, micro, and macroscopic mechanical properties of dense AlSi10Mg samples fabricated by SLM. Nanoindentation revealed the hardness profile across individual melt pools building up the parts to be uniform. This is due to the fine microstructure and uniform chemical elements distribution developed during the process due to rapid solidification. Micro-hardness testing showed anisotropy in properties according to the build orientation driven by the texture produced during solidification. Lastly, the tensile and compressive behaviours of the parts were examined showing high strength under both loading conditions as well as adequate amounts of strain. These superior mechanical properties compared to those achieved via conventional manufacturing promote SLM as promising for several applications.

null

['Li, Yingqi', 'Leu, Ming C.', 'Tsai, Hai-Lung']

2021-11-11T15:25:38Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90219', 'http://dx.doi.org/10.26153/tsw/17140']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['metallic glass', 'laser processing', 'additive manufacturing', 'mechanical properties']

Mechanical Properties of Zr-Based Bulk Metallic Glass Parts Fabricated by Laser-Foil-Printing Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/bc9f5a39-0fa5-4d18-a8f7-72f4216d1e6e/download

University of Texas at Austin

The application of bulk metallic glasses (BMGs) has been traditionally limited to parts with small dimensions and simple geometries, due to the requirement of fast cooling during the conventional process of casting. This research exemplifies a promising additive manufacturing method, i.e., laser-foil-printing (LFP), to fabricate high-quality BMG parts with large dimensions and complex geometries. In this study, Zr52.5Ti5Al10Ni14.6Cu17.9 BMG parts were fabricated by LFP technology in which MG foils are laser welded layer-by-layer upon a substrate. The mechanical properties of the fabricated BMG parts were measured using micro-indentation, tensile test and four-point bending test, and then compared to as-cast BMG parts. Through LFP, as rapid cooling rates can be achieved, fully amorphous and nearly fully dense BMG parts without cracking have been successfully made. The fabricated BMG parts exhibit mechanical properties, including micro-hardness, tensile strength, and flexural strength, comparable with the as-cast BMG parts.

null

['Snarr, Scott E.', 'Beaman, Joseph J. Jr', 'Fish, Scott']

2021-11-10T21:44:27Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90186', 'http://dx.doi.org/10.26153/tsw/17107']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['parameter development', 'set point development', 'laser parameter', 'set point', 'selective laser sintering', 'carbon fiber reinforced polyetheretherketone', 'CFR PEEK']

Mechanical Property Correlation and Laser Parameter Development for the Selective Laser Sintering of Carbon Fiber Reinforced Polyetheretherketone

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a81ead32-4ca1-43c1-a609-c6be3d05d663/download

University of Texas at Austin

null

This thesis specifically investigates parameter and set point development for a material novel to the SLS process, Carbon Fiber Reinforced Polyetheretherketone (CFR PEEK).

null

['Khalid Rafi, H.', 'Karthik, N.V.', 'Starr, Thomas L.', 'Stucker, Brent E.']

2021-10-06T20:27:44Z

8/16/12

Mechanical Engineering

null

['https://hdl.handle.net/2152/88434', 'http://dx.doi.org/10.26153/tsw/15371']

eng

2012 International Solid Freeform Fabrication Symposium

Open

['Ti-6Al-4V', 'electron beam melting', 'mechanical properties']

Mechanical Property Evaluation of Ti-6Al-4V Parts Made Using Electron Beam Melting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/051d1544-3fd3-464a-bc15-7b8455f6a6a8/download

University of Texas at Austin

Cylindrical Ti-6Al-4V parts were built in vertical and horizontal orientations using electron beam melting. Tensile tests and fatigue tests were carried out. The specimens were tested in as-built and machined conditions to understand the effect of surface finish on mechanical properties. The fracture surfaces were analyzed using scanning electron microscopy and the fractography results were correlated with the mechanical properties. Based on the results the effects of part orientation and surface finish on mechanical properties are discussed.

null

['Dietrich, S.', 'Karcher, B.', 'Popp, U.', 'Scholz, J.']

2024-03-27T15:52:45Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124492', 'https://doi.org/10.26153/tsw/51100']

en

2023 International Solid Freeform Fabrication Symposium

Open

['fused filament fabrication', 'material extrusion', 'surface treatment', 'polymer']

Mechanical Surface Treatment of Polymer Parts Produced by FFF

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e714423b-107c-4952-8eac-26b6e4bf94a5/download

University of Texas at Austin

The surface structure in the form of waviness and roughness as well as near surface density of FFF parts represents a major issue with respect to mechanical performance especially under fatigue loading. Mechanical surface treatments like shot peening or rolling are commonly used techniques, especially for metal components, to reduce surface roughness, increase surface densification and create beneficial residual stress states in the surface layer. In this study, a rolling process has been applied intermittently with the layer-wise FFF process and the effect on the surface state has been investigated using laser scanning and optical microscopy as well as microcomputed tomography. A process window with different rolling tools and rolling paths has been identified and analysed. The results show clearly advantageous properties regarding an improved surface roughness, with a higher densification gradient in the first perimeter tracks of the FFF extrusion strategy as well as sharper corners being realized.

null

['Dongare, Suijitkumar', 'Sparks, Todd E.', 'Newkirk, Joseph', 'Liou, Frank']

2021-10-12T21:31:17Z

2014

Mechanical Engineering

null

['https://hdl.handle.net/2152/88745', 'http://dx.doi.org/10.26153/tsw/15679']

eng

2014 International Solid Freeform Fabrication Symposium

Open

['additive manufacturing', 'mini-tensile', 'mini-tensile testing', 'tensile properties']

A Mechanical Testing Methodology for Metal Additive Manufacturing Processes

Conference paper

https://repositories.lib.utexas.edu//bitstreams/7c7d22a9-ab67-45f8-b6cb-e3b61282b90a/download

University of Texas at Austin

Most additive manufacturing processes are layer-by-layer deposition, thus its mechanical properties could be very different than those made from traditional manufacturing processes. This paper summarizes a mini-tensile testing methodology for additive manufacturing. Research concerning the tensile testing of metallic material has been conducted and test methods have been defined. It encompasses the methods for determination of yield strength, yield point elongation, tensile strength, elongation, and reduction of area. The study of positional variation and cooling-rate dependency in case of additive manufacturing proves to be expensive and time consuming with the full-size test specimens. Thus, this paper discussed a technique for testing of tensile properties using miniature sized test specimens. It covers detailed procedures for development of test specimens, actual testing set-up and the analysis of test results.

null

['Weflen, E.D.', 'Peters, F.E.', 'Frank, M.C.']

2024-03-26T21:30:14Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124418', 'https://doi.org/10.26153/tsw/51026']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['big area additive manufacturing', 'print surface', 'additive manufacturing']

MECHANICALLY BONDING AND THERMALLY RELEASING PRINT SURFACE FOR BIG AREA ADDITIVE MANUFACTURING

Conference paper

https://repositories.lib.utexas.edu//bitstreams/83a07885-a65b-4af2-afb3-d6e0d61b037e/download

University of Texas at Austin

Part retention and removal are challenges for Big Area Additive Manufacturing (BAAM) systems, increasing production costs and impacting part quality. A part should remain locked to the print surface during processing and then be released for removal when processing is completed. However, a method for releasing large, multi-meter parts from the print surface on BAAM systems is nonexistent. This work presents a print surface with a mechanically bonding interfacial structure that locks the part to the print surface during processing and then thermally releases the part for removal. Design and process parameters were evaluated, and a model was developed as a design guide for industry implementation. A demonstration casting pattern was produced in a hybrid manufacturing machining center by iterating between polymer pellet-fed material extrusion and surface machining. The viable applications of BAAM can be expanded by improving the process and reducing costs.

null

['Ramos, Jorge', 'Bourell, David']

2019-11-21T18:28:43Z

2003

Mechanical Engineering

null

['https://hdl.handle.net/2152/78560', 'http://dx.doi.org/10.26153/tsw/5616']

eng

2003 International Solid Freeform Fabrication Symposium

Open

Surface Interaction

Mechanics of the Selective Laser Raster-Scanning Surface Interaction

Conference paper

https://repositories.lib.utexas.edu//bitstreams/43516d5d-52bf-4600-a557-59751b7871d9/download

null

In recent years, the use of a high power laser beam actuated by fast speed scanning mirrors has opened up novel selective laser raster-scan processing venues as extremely rapid motion and high overlapping of the beam can be attained. This permits distribution of laser energy precisely over geometric patterns such as rectangles, circles, triangles etc. The surface thermal history at any given point under such processing was estimated using an analytical solution for the 1D, semi-infinite, surface flux boundary condition heat conduction problem together with linear superposition theory. Presented here is the comparison of the thermal histories of different selective laser surface processes previously implemented, namely: laser surface polishing of flat surfaces, laser induced cementation of cylindrical surfaces and direct laser single layer masked deposition. It was possible to verify that in laser induced cementation, long-width and short-length scanned regions provided low average temperature and low heating rate with spaced out temperature peaks, whereas for direct laser single layer deposition in which a narrow-width – long-length region is scanned, the heating rate and peak temperature are higher and the peaks are squeezed. The analysis also provided ways to estimate the Andrew’s number associated with a raster-scan process for the sake of comparison with single-beam processes having a given number value. Understanding the influence of scan geometry and overlapping on the selective raster-scan processing provides a method to tailor the surface peak temperature as well as the heating and cooling rates, affecting the solidification or sintering conditions and therefore the mechanical properties of the parts obtained.

null

['Dwivedi, Rajeev', 'Zekovic, Srdja', 'Kovacevic, Radovan']

2020-02-24T14:25:29Z

2005

Mechanical Engineering

null

['https://hdl.handle.net/2152/80074', 'http://dx.doi.org/10.26153/tsw/7095']

eng

2005 International Solid Freeform Fabrication Symposium

Open

Solid Freeform Fabrication

Mechanism for Determination of G-factors for Solid Freeform Fabrication Techniques Based on Large Heat Input

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e2d87489-6368-435c-82af-456a491b4fca/download

null

A major class of Solid Freeform Fabrication (SFF) methods for metal deposition are based on large heat input. The geometry and microstructural properties of the deposition depend primarily on the heat input and the subsequent distribution at the substrate. On one hand the insufficient heat may lead to the inadequate melting of the metal, on the other hand overheating and heat accumulation leads to the overmelting, resulting in the deformation of the build up geometry. The heat distribution is governed by the available heat sink . For a better control of the process, the estimation of heat sinks and the subsequent control of the energy input allows a better control of the process. A parameter G-factor that estimates the heat sink based on the local geometry of a part has been introduced. The estimation of G-factor is based on the simulation and the experimental results. Also a mechanism to determine the G-factor for various substrate geometries has been introduced.

null

['Nussbaum, J.', 'Crane, N.B.']

2021-10-12T20:15:51Z

2014

Mechanical Engineering

null

['https://hdl.handle.net/2152/88731', 'http://dx.doi.org/10.26153/tsw/15665']

eng

2014 International Solid Freeform Fabrication Symposium

Open

['post processing deformation', 'additive manufacturing', 'selective heating', 'multimaterial fabrication', 'selective deformation']

Mechanisms for Post Processing Deformation without Part-Specific Tooling

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3acfbb8d-9345-43d7-90e7-39134e8c8de0/download

University of Texas at Austin

Post processing deformation of additive manufactured components offers many advantages from reduced printing time and material usage to simplified multimaterial fabrication. For thermoplastic components, controlled deformations can be achieved by locally heating to temporarily soften the material. This paper investigates multiple methods of selectively heating and deforming desired locations to form the final component. The deformation location can be controlled by geometry (thickness), surface properties (reflectivity) or by local addition of a secondary material to control the heating. Demonstrations are provided for each of these deformation methods and then an example is provided to show how this approach could produce customized geometries from a standard feature.

null

['Gong, Haijun', 'Gu, Hengfeng', 'Zeng, Kai', 'Dilip, J.J.S.', 'Pal, Deepankar', 'Stucker, Brent']

2021-10-12T21:42:50Z

2014

Mechanical Engineering

null

['https://hdl.handle.net/2152/88748', 'http://dx.doi.org/10.26153/tsw/15682']

eng

2014 International Solid Freeform Fabrication Symposium

Open

['Selective Laser Melting', 'pre-alloyed powder', 'Ti-6Al-4V', 'parameter optimization', 'single bead fabrication', 'melt', 'melt pool geometry']

Melt Pool Characterization for Selective Laser Melting of Ti-6Al-4V Pre-alloyed Powder

Conference paper

https://repositories.lib.utexas.edu//bitstreams/a5f2b2be-36f6-4b50-aa11-a0e6b9b214f2/download

University of Texas at Austin

Parameter optimization for metal powders in Selective Laser Melting (SLM) is usually carried out by experimental investigations of the influence of significant parameters (such as laser power, scan speed, hatch spacing, layer thickness, scan pattern, etc.) on microstructure and/or mechanical properties. This type of experimental optimization is extremely time- and cost-consuming. In order to accelerate the optimization process, a study was undertaken to develop a method for rapid optimization of parameters based on melt pool characterizations. These characterizations began with investigations of SLM single bead experiments. Pre-alloyed Ti-6Al-4V powder was used for single bead fabrication with multiple laser power and scan speed combinations. Surface morphology and dimensions of single beads were characterized. Geometrical features of melt pools were measured after polishing and etching of the cross section of each single bead. It was found that melt pool characteristics provide significant information that is helpful for process parameters selection. These experiments are being extended to characterize test pads with multiple layers.

null

['Cheng, Bo', 'Lydon, James', 'Cooper, Kenneth', 'Cole, Vernon', 'Northrop, Paul', 'Chou, Kevin']

2021-11-03T21:46:48Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89942

eng

2017 International Solid Freeform Fabrication Symposium

Open

['selective laser melting', 'SLM', 'infrared imaging', 'melt pool size']

Melt Pool Dimension Measurement in Selective Laser Melting Using Thermal Imaging

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e83de706-0558-4a39-8d0d-ec07d24bddcf/download

University of Texas at Austin

Process temperature measurement for selective laser melting (SLM) can provide critical information such as melt pool dimension for real-time part quality control. In this study, a MCS640 LumaSense thermal imager was utilized to collect process radiant temperature information during SLM fabrication using Inconel718 powder. Identified liquidus-solidus transition was used to calculate melt pool size. Speed effect on melt pool dimension has been investigated. The major findings are as follows. (1) At a beam power of 180 W, the averaged melt pool has dimensions of about 0.39 mm and 0.23 mm in length and width for 400 mm/s scanning speed. (2) No significant difference has been observed for melt pool size at different build height for a given scanning speed. (3) Melt pool width decreases with the increase of scanning speed, while similar melt pool length was observed at different speed under a laser power of 180 W.

null

['Cheng, Bo', 'Chou, Kevin']

2021-10-21T17:53:57Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89410

eng

2015 International Solid Freeform Fabrication Symposium

Open

['selective laser melting', 'raster scan', 'finite element method', 'remelting']

Melt Pool Evolution Study in Selective Laser Melting

Conference paper

https://repositories.lib.utexas.edu//bitstreams/78c63eff-d72e-4f06-9bef-007429c512f4/download

University of Texas at Austin

In selective laser melting (SLM) additive manufacturing, the completion of the entire scanning cross-sectional area of each layer build is consisted of many smaller scanning patches. Hence, the scanning length in each path may be too short to reach the melt pool quasi-steady state, thus, affecting the melt pool geometry, which is also effected by the process parameters. It is also known that the melt pool size correlates with the build part microstructures and properties. In this study, temperature simulations, finite-element based, of SLM for In718 is applied to track the thermal response during scanning of an individual patch. The results show that the process parameters determine the melt pool evolution, which affects the actual molten pool size in the regions defined by the raster scanning length. Manipulating the scanning path length and process parameters, based on the melt pool evolution information, may help to achieve a desired melt pool size for part quality controls.

null

['Park, Bumsoo', 'Wang, Xin', 'Mishra, Sandipan', 'Bristow, Douglas', 'Landers, Robert']

2023-01-27T13:48:46Z

2022

Mechanical Engineering

null

['https://hdl.handle.net/2152/117331', 'http://dx.doi.org/10.26153/tsw/44212']

eng

2022 International Solid Freeform Fabrication Symposium

Open

powder bed fusion

Melt Pool Feature Extraction, Spatial Registration, and Layer-To-Layer Control in Powder Bed Fusion

Conference paper

https://repositories.lib.utexas.edu//bitstreams/b26e8da3-325a-4e28-91ab-a9386c704332/download

null

Laser Powder Bed Fusion (LPBF) is a well-known additive manufacturing technique that uses a high- power laser to fuse loose metal powder into a solid part. A major issue restricting this technology from wider industrial applications is the lack of part quality assurance. In this paper, a high-speed (2kHz) co-axial near- infrared optical camera setup is implemented for process monitoring and control. The acquisition locations for individual images are estimated based on specified scan paths and scan velocities to create a spatial registration technique. Melt pool thermal features are linked to specific locations instead of time instants, motivating a spatial control strategy to achieve thermal feature uniformity. Based on the spatial mapping of the thermal features, experimental studies are conducted where a spatial layer-to-layer iterative learning controller is implemented to achieve spatial uniformity of the thermal features. The experimental results present a convergence of the thermal features to a uniform level.

null

['Cheng, Bo', 'Chou, Kevin']

2021-10-11T21:49:05Z

8/16/13

Mechanical Engineering

null

['https://hdl.handle.net/2152/88655', 'http://dx.doi.org/10.26153/tsw/15589']

eng

2013 International Solid Freeform Fabrication Symposium

Open

['design of experiments', 'electron beam additive manufacturing', 'melt pool geometry', 'process parameters', 'thermal modeling']

Melt Pool Geometry Simulations for Powder-Based Electron Beam Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3b6f3c78-0e0c-4e92-b37c-7da0f666509e/download

University of Texas at Austin

It is known that the melt pool geometry and dynamics strongly affect the build part properties in metal-based additive manufacturing (AM) processes. Thus, process temperature predictions may offer useful information of the melt pool evolution during the heating-cooling cycle. A transient thermal modeling for powder-based electron beam additive manufacturing (EBAM) process has been developed for process temperature simulations, considering temperature and porosity dependent thermal properties. In this study, the thermal model is applied to evaluate, for the case of Ti-6Al-4V in EBAM, the process parameter effects, such as the beam speed, on the temperature profile along the melt scan and the corresponding melt pool geometric characteristics such as the lengthdepth ratio and the cross-sectional area. The intent is to establish a process envelop for part quality control.

null

['Sampson, R.', 'Lancaster, R.', 'Weston, M.']

2021-11-04T14:06:30Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89964

eng

2017 International Solid Freeform Fabrication Symposium

Open

['image process acceleration', 'image processing', 'melt pool', 'General Purpose', 'Graphics Processing Units', 'direct energy deposition']

Melt Pool Image Process Acceleration Using General Purpose Computing on Graphics Processing Units

Conference paper

https://repositories.lib.utexas.edu//bitstreams/e6935e2b-6840-4f34-b9fd-158cf3c51310/download

University of Texas at Austin

The additive manufacturing (AM) process is incredibly complex, and the intricate web of changing process parameters can result in poor repeatability and structural consistency. New geometric designs result in an initial iteration process to optimise build parameters, which is highly laborious and time consuming. A deep understanding of process parameters in AM, and the ability to control and manipulate said parameters, may lead to advanced AM capabilities. Non-contact devices are typically required to measure the build characteristics such as melt pool geometry and temperature, which give a greater understanding of the complex AM process. This paper will look to view the molten metal pool that is formed in the Direct Energy Deposition (DED) process using complementary metal-oxide-semiconductor (CMOS) cameras and presents a new method of using General Purpose computing on Graphics Processing Units (GPGPU) to accelerate the image processing technique for such applications.

null

['Gibson, B.T.', 'Bandari, Y.K.', 'Richardson, B.S.', 'Roschli, A.C.', 'Post, B.K.', 'Borish, M.C.', 'Thornton, A.', 'Henry, W.C.', 'Lamsey, M.', 'Love, L.J.']

2021-11-18T18:06:47Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90450', 'http://dx.doi.org/10.26153/tsw/17371']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['melt pool monitoring', 'large scale metal additive manufacturing', 'laser-wire based directed energy deposition', 'Oak Ridge National Laboratory', 'GKN Aerospace']

Melt Pool Monitoring for Control and Data Analytics in Large-Scale Metal Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f01edcc5-ce0a-482b-9ea6-8388aafebaf0/download

University of Texas at Austin

Laser-wire based Directed Energy Deposition (DED) processes are being developed at Oak Ridge National Laboratory’s Manufacturing Demonstration Facility, in collaboration with GKN Aerospace, for large volume metal additive manufacturing of metallic structures. The technology has the potential to deliver reduced costs and lead times when compared to conventional methods of manufacturing in several industries. While complex structures are being produced with relatively high deposition rates and at near-net shape, issues persist with achieving consistent geometric accuracy and thermal stability. A significant research effort is focused on developing coordinated, multi-modal sensing and control for addressing these issues. An introduction to this large-volume metal process will be provided, followed by investigations into real-time thermal monitoring capabilities that support control and data analytics frameworks. Studies focused on melt pool monitoring via infrared thermography, thermal and geometric effects on melt pool size measurement, and interactions between process variables and thermal monitoring metrics are presented.

null

['Aggarangsi, Pruk', 'Beuth, Jack L.', 'Griffith, Michelle']

2019-11-20T16:13:25Z

2003

Mechanical Engineering

null

['https://hdl.handle.net/2152/78468', 'http://dx.doi.org/10.26153/tsw/5553']

eng

2003 International Solid Freeform Fabrication Symposium

Open

Laser-Based Deposition

Melt Pool Size and Stress Control for Laser-Based Deposition Near a Free Edge

Conference paper

https://repositories.lib.utexas.edu//bitstreams/6537b774-f88d-4cb2-88fd-cf399e166304/download

null

Thermomechanical models developed in this research address two experimental observations made during the deposition of thin-walled structures by the LENSTM process. The first observation (via thermal imaging) is of substantial increases in melt pool size as a vertical free edge is approached under conditions of constant laser power and velocity. The second observation (via neutron diffraction) is of large tensile stresses in the vertical direction at vertical free edges, after deposition is completed and the wall is allowed to cool to room temperature. At issue is how to best control melt pool size as a free edge is approached and whether such control will also reduce observed free edge stresses. Thermomechanical model results are presented which demonstrate that power reduction curves suggested by process maps for melt pool size under steady-state conditions can be effective in controlling melt pool size as a free edge is approached. However, to achieve optimal results it is important that power reductions be initiated before increases in melt pool size are observed. Stress simulations indicate that control of melt pool size can reduce free-edge stresses; however, the primary cause of these stresses is a constraint effect which is independent of melt pool size.

This research was supported by the National Science Foundation Division of Design, Manufacture and Industrial Innovation, through the Materials Processing and Manufacturing Program, award number DMI-0200270.

null

['Vasinonta, Aditad', 'Beuth, Jack L.', 'Ong, Raymond']

2019-10-18T16:08:43Z

2001

Mechanical Engineering

null

['https://hdl.handle.net/2152/76248', 'http://dx.doi.org/10.26153/tsw/3337']

eng

2001 International Solid Freeform Fabrication Symposium

Open

Thin-Walled

Melt Pool Size Control in Thin-Walled and Bulky Parts via Process Maps

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5fd62660-b1b1-4c55-bdaf-79a71aa008bd/download

null

Control of melt pool size is critical for maintaining consistent build conditions in the solid freeform fabrication of complex shapes. In this research, melt pool size in laser-based solid freeform fabrication processes is studied for both thin-walled structures and bulky parts. Numerical simulations are used to construct non-dimensional plots (termed process maps) that quantify the effects of changes in part height, laser power, deposition speed and part preheating on melt pool size. Strategies for the control of melt pool size suggested by the process maps are similar for the two geometries. Insights are given as to how transitions between these two extremes in geometry can be managed to maintain a consistent melt pool size. This modeling work is being performed in tandem with process development and melt pool imaging and control research underway on the LENS process at Sandia National Laboratories

This research has been supported by the National Science Foundation under grant DMI9700320 and by Sandia National Laboratories under grant BE-0792.

null

['Patel, S.', 'Vlasea, M.L.']

2021-11-18T17:08:01Z

2019

Mechanical Engineering

null

['https://hdl.handle.net/2152/90431', 'http://dx.doi.org/10.26153/tsw/17352']

eng

2019 International Solid Freeform Fabrication Symposium

Open

['process parameter', 'temperature prediction', 'melting mode thresholds', 'laser powder bed fusion']

Melting Mode Thresholds in Laser Powder Bed Fusion and Their Application Towards Process Parameter Development

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c73ac52d-dc19-4bd0-a551-f2af205e712c/download

University of Texas at Austin

Depending on processing conditions, laser powder bed fusion (LPBF) has broadly two different processing regimes, conduction and keyhole mode. Heat conduction governs the melt pool morphology observed in conduction mode melting. In contrast, keyhole mode melting is observed when the morphology of the molten pool is controlled by thermo-capillary convection and recoil momentum pressure generated by vaporization of a given material. Additionally, there exists another melting mode called transition mode wherein the dominance of conduction or convection depends on processing conditions. In this work, we use an analytical temperature prediction model, along with normalized processing diagrams, to obtain a processing window for achieving highdensity three-dimensional Ti-6Al-4V parts on a continuous beam exposure LPBF system. The normalized processing diagrams in this work help visualize the three melting modes - conduction, transition, and keyhole mode. The temperature prediction model can be used to predict the thresholds between the three melting modes. This work can be used for understanding the physical origins of defects in three-dimensional LPBF parts, as well as lower the risk of costly experimentation to go from powder to near fully dense products.

null

['Choi, S. H.', 'Kwok, K. T.']

2019-03-12T16:06:11Z

1999

Mechanical Engineering

null

['https://hdl.handle.net/2152/73593', 'http://dx.doi.org/10.26153/tsw/735']

eng

1999 International Solid Freeform Fabrication Symposium

Open

['Rapid Prototyping', 'CAD']

A Memory Efficient Slicing Algorithm for Large STL Files

Conference paper

https://repositories.lib.utexas.edu//bitstreams/ad7238eb-9717-402d-ba5f-87154bebe67c/download

null

This paper proposes a memory efficient slicing algorithm for Rapid Prototyping (RP) processes. The algorithm is aimed to overcome the constraints of computer memory inherent in the .conventional slicing methodologies.lte~tracts from the Stereolithography (STL) file the facets that intersect with the cutting plane to process the slice data and the topological information. Reading onlythefacets ofthe current layer greatly reducestheatnount ofcomputer memory required <and involves less •computationally intensive. searching operations. Th~s, large SThfiles>of virtually~nlimitedsizescan be sliced to facilitate theRt> process. The algorithm is alsorelativelyfau;lt-tolerant in that inconsistent contour due to defects of the STL file may be l11()reeffectiVelyrepaired. The topologicaLinformation of the layer contours can be subsequel1tlyprocessed by further operations, such as hatching, physical fabrication or virtual simulation. To cater for the variations of RP processes, the Common Layer Interface (CLI) format is adopted as the output interface.

null

['Park, Byong-Ho', 'Prinz, Fritz B.']

2019-09-23T15:30:27Z

2000

Mechanical Engineering

null

['https://hdl.handle.net/2152/75937', 'http://dx.doi.org/10.26153/tsw/3036']

eng

2000 International Solid Freeform Fabrication Symposium

Open

Assemblies

Mesoscopic Assemblies with SDM Processing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/5f6aed92-7d46-4e79-aa2d-6af56ece64bc/download

null

Shape Deposition Manufacturing (SDM) is a layered manufacturing process capable of building complex 3D parts through the combination of material addition and subtraction. Overhangs can be built with the help of sacrificial support materials. SDM achieves high surface quality by taking advantage of material subtraction by CNC machining. High surface quality in turn enables the fabrication of pre-assembled mechanisms that can be freed to turn or slide after removal of sacrificial support materials. Using SDM, miniature trailing-edge effectors (MiTEs), which are pneumatic actuators with the minimum feature size of about 500 P KDYH EHHQ fabricated for aeroelastic control of uninhabited air vehicles (UAV’s). However, as part size is VFDOHGGRZQ OLPLWLQJSURFHVVLQJFRQVWUDLQWVZHUHREVHUYHG 7RGDWHFOHDUDQFHVRI PFRXOG be achieved in MiTEs. Also, this paper will discuss limiting manufacturing constraints and planning issues unique to the size range which is frequently referred to as the ‘mesoscopic’ regime.

null

['Shrestha, Subin', 'Chou, Kevin']

2021-11-03T21:28:19Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89937

eng

2017 International Solid Freeform Fabrication Symposium

Open

['powder distribution', 'selective laser melting', 'thermo-fluid model']

Mesoscopic Multilayer Simulation of Selective Laser Melting Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/62998607-e229-4011-8b15-5defe25954fb/download

University of Texas at Austin

Selective Laser Melting (SLM) is a metal additive manufacturing with complex process physics that requires understanding of metallic particle accumulations and interactions to layer additions. In this work, a mesoscopic multilayer numerical model with volume of fluid (VOF) method is developed using ANSYS/FLUENT. At first, a sequential powder adding algorithm is applied to generate a layer of randomly distributed particles of non-uniform sizes over a solid substrate. A moving volumetric heat source is then applied to melt a single track in the powder layer which is defined by specifying temperature dependent material properties. After the single scan in the first layer is completed, the surface data is acquired to re-apply sequential powder adding algorithm over the deformed surface to generate second layer of powder. In this study, the melt flow has been simplified and is driven primarily by constant surface tension applied over the melt pool. The obtained track width from simulations is in reasonable agreement with experimental results in literature.

null

['Lee, Y.S.', 'Zhang, W.']

2021-10-21T17:10:03Z

2015

Mechanical Engineering

null

https://hdl.handle.net/2152/89408

eng

2015 International Solid Freeform Fabrication Symposium

Open

['particle size distribution', 'additive manufacturing', 'volume of fluid', 'powder bed fusion']

Mesoscopic Simulation of Heat Transfer and Fluid Flow in Laser Powder Bed Additive Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/3516540e-ffc0-4f11-884a-943f56ac3669/download

University of Texas at Austin

Laser-powder bed fusion (L-PBF) additive manufacturing involves complex physics such as heat transfer and molten metal flow, which have a significant influence on the final build quality. In this study, transport phenomena based modeling is used to provide a quantitative understanding of complex molten pool transients. In particular, a three dimensional (3D), transient numerical model is developed for L-PBF additive manufacturing by solving the governing partial differential equations of mass, momentum and energy conservation. The individual powder particles are resolved using the volume of fluid method (VOF) method with a fine mesh size of 3 μm (thus at meso-scale). The powder particle arrangement including particle size distribution and packing density are taken into account in placement of individual particles calculated using discrete element method. Moreover, the model considers Marangoni shear stress, an important driving force for molten metal flow. The numerical model is used to quantitatively study the effect of laser power, scanning speed, and powder size distribution on the bead geometry and formation of balling defect.

null

['Vendra, L.', 'Achanta, A.']

2021-11-09T18:43:44Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90114', 'http://dx.doi.org/10.26153/tsw/17035']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['metal additive manufacturing', 'additive manufacturing', 'oil industry', 'gas industry']

Metal Additive Manufacturing in the Oil and Gas Industry

Conference paper

https://repositories.lib.utexas.edu//bitstreams/716250ad-ce25-4c2c-b70c-5a62f4105c17/download

University of Texas at Austin

Additive Manufacturing (AM) has gained increasing prominence and had the most significant commercial impact in the aerospace sector in the last few years. The adoption of AM in the oil and gas industry has been slow, although the potential economic benefits it offers are tremendous. Improving product performance, reducing costs and lead time, creating a more flexible and distributed supply chain are some of the major focus areas for the oil and gas industry today which cannot be attained through traditional manufacturing methods. A broad overview of the state of Metal AM pertaining to oil and gas applications is provided. Potential applications of AM in the oilfield are highlighted, including demonstrated examples such as components for downhole logging and drilling tools, turbomachinery, pipeline components, etc. A lack of qualification and certification methodologies, along with technical and cultural challenges that hamper AM’s adoption in the industry are discussed.

null

['Liu, Z. E.', 'Wei, P.', 'Kernan, B.', 'Heuer, A. H.', 'Cawle, J. D.']

2018-11-14T20:00:00Z

1996

Mechanical Engineering

doi:10.15781/T2SB3XJ3K

http://hdl.handle.net/2152/70260

eng

1996 International Solid Freeform Fabrication Symposium

Open

['CAM-LEM', 'sheet feedstocks', 'microstructure']

Metal and Ceramic Components made via CAM-LEM Technology

Conference paper

https://repositories.lib.utexas.edu//bitstreams/31760035-0c9d-4bc6-902c-95c4687c94a3/download

null

CAM-LEM (Computer-Aided Manufacturing ofLaminated Engineering Materials) is an SFF technology suitable for many engineering materials for which feedstock is available in sheet form; lamination and post-processing procedures are materials specific. Two methods for producing sheetstock, tapecasting and compression molding , are discussed and contrasted. Ceramic and metallic components that have been produced via CAM-LEM are described.

null

['Himmer, Thomas', 'Techel, Anja', 'Nowotny, Steffen', 'Beyer, Eckhard']

2020-02-13T20:02:46Z

2004

Mechanical Engineering

null

['https://hdl.handle.net/2152/79972', 'http://dx.doi.org/10.26153/tsw/6997']

eng

2004 International Solid Freeform Fabrication Symposium

Open

fast manufacturing

Metal Laminated Tooling - A Quick and Flexible Tooling Concept

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c23791d5-893d-4e84-9789-aea03b13ae9e/download

null

For the fast manufacturing of complex formed tools Fraunhofer IWS works together with partners from the industry on a constant automation solution for cutting, packaging and adding steel sheet cutouts. With the selection of the most suitable connecting technology, also requirements must be considered to quality, surface quality and the production costs. Deep drawing or stamping tools do not require a complete connection of the single metal sheets. Here, a fast and economical connection is the main objective. Due to simple automation, laser beam welding offers itself as joining process. On the other hand, a temperature-steady connection of the sheet metal lamellas is necessary for injection molds, which can resist the injection pressures.

null

['Badrinarayan, B.', 'Barlow, J.W.']

2018-04-19T17:34:50Z

1992

Mechanical Engineering

doi:10.15781/T2988346K

http://hdl.handle.net/2152/64391

eng

1992 International Solid Freeform Fabrication Symposium

Open

['Department of Chemical Engineering', 'Electric Discharge Machining', 'PMMA']

Metal Parts From Selective Laser Sintering of Metal-Polymer Powders

Conference paper

https://repositories.lib.utexas.edu//bitstreams/c64bf3a6-31e0-4d3a-926e-23bb362bd674/download

null

['Michaels, Steven', 'Sachs, Emanuel M.', 'Cima, Michael J.']

2018-04-19T18:23:52Z

1992

Mechanical Engineering

doi:10.15781/T2GT5FZ5X

http://hdl.handle.net/2152/64405

eng

1992 International Solid Freeform Fabrication Symposium

Open

['Three Dimensional Printing', 'rapid prototyping', '3DP']

Metal Parts Generation by Three Dimensional Printing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/08918ab7-33f2-4309-9250-3af3deab9645/download

null

['Knight, Ronald', 'Wright, Joseph', 'Beaman, Joseph', 'Freitag, Douglas']

2018-11-14T18:04:24Z

1996

Mechanical Engineering

doi:10.15781/T22V2CW3Q

http://hdl.handle.net/2152/70255

eng

1996 International Solid Freeform Fabrication Symposium

Open

['SLS', '3D CAD', 'DTM']

Metal Processing Using Selective Laser Sintering and Hot Isostatic Pressing (SLSIHIP)

Conference paper

https://repositories.lib.utexas.edu//bitstreams/1274daa5-78ec-420f-aaff-8c6a18ffdac2/download

null

In July of 1995 the Office of Naval Research (ONR) awarded a contract to Loral Vought Systems entitled Low Cost Metal Processing Using SLSIHIP. The two-phase, four-year program is co-sponsored by ONR and the Defense Advanced Research Projects Agency, DARPA. The program addresses the DoD and Navy need to improve the reprocurement, remanufacture and repair methodology for high value metal parts. The specific program objective is to develop and demonstrate Selec~:ve Laser Sintering (SLS) as a lower cost, flexible and faster method of fabricating spare and replacement, small/medium sized powder metal parts for DoD weapon systems. Current activity is f~cused on development of a high temperature SLS workstation and on selective laser sintering trials on candidate metal powders including Inconel, molybdenum and titanium.

null

['Druschitz, A.P.', 'Cowden, S.', 'Dudley, A.', 'Walsh, S.', 'Weir, A.', 'Williams, C.B.', 'Wood, B.']

2021-11-01T21:16:36Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89756

eng

2016 International Solid Freeform Fabrication Symposium

Open

['metal casting', '3D printed sand', 'mesostructure', 'ceramics', 'composites', 'encapsulation']

Metal-Ceramic Composite Lattice Structures Using 3D Printed Sand Molds and Cores

Conference paper

https://repositories.lib.utexas.edu//bitstreams/951a1e00-e10a-4968-9bac-11dfaf7d16c7/download

University of Texas at Austin

Binder Jetting of sand molds for metal casting provides a scalable and efficient means of fabricating large metal parts with complex geometric features made possible only by Additive Manufacturing. For example, in earlier work, the authors demonstrated the use of Binder Jetting to fabricate complex mold structures for casting large-scale, lightweight metallic lattice structures and sandwich panels that could not be made through either traditional sand casting or through other direct metal AM techniques. In this paper, the authors demonstrate the fabrication of metal-ceramic composite lattice structures via embedding ceramic tiles into the printed mold package. The addition of ceramic tiles can add resistance to penetrators and/or radiation shielding to the lightweight lattice structures, which can be tailored for energy absorbing performance. 3D printed mold and core designs for metal and metal-ceramic composite lattice castings are described along with 3D printed mold designs for encapsulating individual metal or ceramic tiles.

null

['Zhang, Xinchang', 'Cui, Wenyuan', 'Li, Wei', 'Liou, Frank']

2021-11-04T15:53:06Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/89990', 'http://dx.doi.org/10.26153/tsw/16911']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['hybrid manufacturing', 'defect repair', 'laser metal deposition', 'reverse engineering']

Metallic Components Repair Strategies Using the Hybrid Manufacturing Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/45c19c9e-0f31-42c3-a1f7-ffc0bd723e6d/download

University of Texas at Austin

The hybrid manufacturing process which integrates additive manufacturing with subtractive machining is competitive and promising in component repair. To automate this process, detecting the missing volume and generating the deposition tracks is the key. In this study, strategies for repairing defects on flat and non-flat surfaces were investigated. A cost-effective reverse engineering tool was utilized to reconstruct STL models of damaged objects. Point data of the fracture surface on flat surfaces was obtained to generate the tool path for material building up. For defects on non-flat surfaces, the damaged model was best-fitted with the nominal model. Then both models were sliced and by using area comparison method, the defective domain was detected. Then a series of projection rays were utilized to slice the damaged cross-sections to extract the repair volume. Finally, repair experiments were performed to assess the repair quality through repair automation.

null

['Fulcher, Ben', 'Leigh, David K.']

2021-10-11T20:20:31Z

2013

Mechanical Engineering

null

['https://hdl.handle.net/2152/88627', 'http://dx.doi.org/10.26153/tsw/15561']

eng

2013 International Solid Freeform Fabrication Symposium

Open

['Harvest Technologies', 'additive manufacturing', 'metal additive manufacturing', 'mechanical property characterization', 'geometrical production', 'aerosp', 'oil', 'aerospace']

Metals Additive Manufacturing Development at Harvest Technologies

Conference paper

https://repositories.lib.utexas.edu//bitstreams/d4fb68b1-a01b-4773-99a5-f7eabc20552a/download

University of Texas at Austin

Harvest Technologies received an EOS M280 in April of 2013 for the production of metal parts through additive manufacturing (AM). Inconel 718 was chosen as a starting material due to its high-end applications in the oil and aerospace industries. Two major areas are of high priority in understanding the machine: (1) mechanical property characterization and (2) geometrical production capability through building prototype models. The following is a working document of Harvest’ progression in developing knowledge in the field of metals AM.

null

['Tominski, J.', 'Lammers, S.', 'Wulf, C.', 'Zimmer, D.']

2021-11-08T23:37:44Z

2018

Mechanical Engineering

null

['https://hdl.handle.net/2152/90079', 'http://dx.doi.org/10.26153/tsw/17000']

eng

2018 International Solid Freeform Fabrication Symposium

Open

['software-based design check', 'design check', 'complex structures', 'additive manufacturing', 'methodology']

Method for a Software-Based Design Check of Additively Manufactured Components

Conference paper

https://repositories.lib.utexas.edu//bitstreams/25bbb57c-8d73-47b4-bf26-60c99faa05aa/download

University of Texas at Austin

Additive manufacturing offers the potential to produce complex structures such as topology-optimized components or lattice structures. However, even these numerically generated structures are subject to manufacturing restrictions. Therefore, compliance with design rules has to be checked to ensure a robust production. For complex structures, this check requires a great effort. Hence, a method for a software-based design check that automatically verifies the compliance with design rules of complex structures has to be developed. Within the framework of the developed method, the frequently used STL format which is usually applied during preparation of the manufacturing process, is used. This format approximates components using triangles. By systematically linking these triangles, geometrical attributes of components which are relevant for a controlled manufacturing can be identified. Comparing these attributes to a database containing attribute limits of divergent manufacturing conditions allows a design check regarding robust manufacturing processes.

null

['Stiltner, L. Justin', 'Elliott, Amelia M.', 'Williams, Christopher B.']

2021-10-05T14:33:55Z

8/17/11

Mechanical Engineering

null

['https://hdl.handle.net/2152/88380', 'http://dx.doi.org/10.26153/tsw/15319']

eng

2011 International Solid Freeform Fabrication Symposium

Open

['PolyJet™ process', '3D printing', 'actuated joints', 'fiber embedding']

A Method for Creating Actuated Joints via Fiber Embedding in a Polyjet 3D Printing Process

Conference paper

https://repositories.lib.utexas.edu//bitstreams/471968d5-567a-44a5-a1c6-f0dac641ec84/download

University of Texas at Austin

The Objet PolyJet direct 3D Printing process is capable of simultaneously depositing two distinct photopolymer materials in preset combinations to enable designers to create parts with graded material properties. For example, this dual-jet process offers designers the ability to combine elastomeric and rigid materials in order to create integrated assemblies featuring stiff components and flexible joints and gaskets. To expand the potential of this technology, the authors have developed a method for the direct fabrication of systems with actuated joints without post-process assembly. The method, which involves temporarily pausing the build process and embedding and anchoring fibers into the part, is described in this paper along with part design considerations. Two systems featuring actuated joints are presented as a means of displaying the embedding method’s capabilities.

null

['Elliott, A.M.', 'Nandwana, P.', 'Siddel, D.', 'Compton, B.G.']

2021-10-28T14:37:15Z

2016

Mechanical Engineering

null

https://hdl.handle.net/2152/89652

eng

2016 International Solid Freeform Fabrication Symposium

Open

['powder bed density', 'binder-jet additive manufacturing', 'powder feedstock', 'shrinkage']

A Method for Measuring Powder Bed Density in Binder Jet Additive Manufacturing Process and the Powder Feedstock Characteristics Influencing the Powder Bed Density

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f413c638-27b9-490b-87bb-beca491ea6eb/download

University of Texas at Austin

Powder bed additive manufacturing involves layer-by-layer spreading of powders before melting, sintering or binding them. Traditionally apparent and tapped density measurements have been carried out to get an estimate of the powder bed density. Powder bed density is especially important in the case of binder-jet additive manufacturing where sintering is carried out as one of the steps to achieve full densification. During densification, shrinkage occurs. The extent of shrinkage depends upon the powder bed density. Thus, it is important to understand the role of powder feedstock on controlling the powder bed density. In the present paper, we have developed a technique to measure the powder bed density. We also used different powder feedstock materials to understand the role of powder size distribution and morphology on the powder bed density. The detailed results are presented.

null

['Chen, Niechen', 'Frank, Matthew C.']

2021-11-04T13:55:24Z

2017

Mechanical Engineering

null

https://hdl.handle.net/2152/89961

eng

2017 International Solid Freeform Fabrication Symposium

Open

['support structure', 'support removal', 'powder bed', 'metal additive manufacturing']

A Method for Metal AM Support Structure Design to Facilitate Removal

Conference paper

https://repositories.lib.utexas.edu//bitstreams/8debb7ae-8cae-4db0-a2d5-f59e60743831/download

University of Texas at Austin

For powder bed metal additive manufacturing (AM), additional post-processing for support structure removal is required. However, this removal process is not formally considered during the design of support structures. Therefore, when either manual or CNC milling is required, some support structures may not be easily removed due to tool accessibility. In this research, with STL model as input, tool accessibility is calculated and used to map onto the facets to grow supports that are more amenable to machined removal. It provides a way to combine previous analysis on support layout with additional information to guide suitable setups; ones that consider not only critical angles requiring support but also removability. This work could enable better support designs that will lead to higher throughput of metal AM by reducing effort and expense in post-process machining.

null

['Auth, C.', 'Arndt, A.', 'Anderl, R.']

2021-11-08T22:18:38Z

2017

Mechanical Engineering

null

['https://hdl.handle.net/2152/90054', 'http://dx.doi.org/10.26153/tsw/16975']

eng

2017 International Solid Freeform Fabrication Symposium

Open

['economic efficiency', 'additive manufacturing', 'conventional manufacturing', 'evaluation']

Method for the Evaluation of Economic Efficiency of Additive and Conventional Manufacturing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/f4288190-74fa-4206-83ce-77c5c1260775/download

University of Texas at Austin

The advantages of individuality and complexity for free are commonly known in the field of additive manufacturing, but, nevertheless, they compete with advantages of conventional manufacturing methods. On the one hand, a small size production can be economically viable through additive manufacturing. On the other hand, conventional manufacturing methods are well known and optimized, so that they have low cost per unit. Therefore, to evaluate the economic efficiency various criteria are needed to compare additive and conventional manufacturing methods. In the following part comparative criteria and influence factors for economic efficiency are identified and described. Besides general aspects personal reasons may influence a manufacturing decision. Therefore, the identified criteria are used to build a method which helps the user to decide on a manufacturing method depending on personal preferences. The structure and use of this method is described in the second part. After this, an outlook and conclusion is given.

null

['Sassaman, D.', 'Phillips, T.', 'Beaman, J.', 'Milroy, C.', 'Ide, M.']

2021-12-07T17:56:42Z

2021

Mechanical Engineering

null

['https://hdl.handle.net/2152/90737', 'http://dx.doi.org/10.26153/tsw/17656']

eng

2021 International Solid Freeform Fabrication Symposium

Open

['powder flowability', 'pre-screening', 'revolution powder analysis', 'machine learning', 'selective laser sintering']

A Method of Predicting Powder Flowability for Selective Laser Sintering

Conference paper

https://repositories.lib.utexas.edu//bitstreams/38f634a5-6744-4bd2-91e0-2a92f55bc319/download

University of Texas at Austin

This work investigates a method for pre-screening material systems for Selective Laser Sintering (SLS) using a combination of Revolution Powder Analysis (RPA) and machine learning. To develop this method, nylon was mixed with alumina or carbon fibers in different wt.% to form material systems with varying flowability. The materials were measured in a custom RPA device and the results compared with as-spread layer density and surface roughness. Machine learning was used to attempt classification of all powders for each method. Ultimately, it was found that the RPA method is able to reliably classify powders based on their flowability, but as-spread layer density and surface roughness were not able to be classified.

null

['Hartman, Aja', 'Zhao, Lihua']

2024-03-26T21:32:02Z

2023

Mechanical Engineering

null

['https://hdl.handle.net/2152/124419', 'https://doi.org/10.26153/tsw/51027']

en_US

2023 International Solid Freeform Fabrication Symposium

Open

['multi jet fusion', 'MJF', '3D printing', 'thermals', 'additive manufacturing']

Method to Balance Thermals for Multi-functional 3D MJF Printing

Conference paper

https://repositories.lib.utexas.edu//bitstreams/9e8a3c44-059c-4227-ba2f-03e38c5da683/download

University of Texas at Austin

HP’s Multi Jet Fusion (MJF) is a powder-based additive manufacturing technology that selectively melts polymer powder, in a layer-by-layer fashion to create 3D parts. There are several different voxel properties that can be modulated using MJF including multi-color, ductility, conductivity, among others. Creating mechanically uniform multi-material parts with varying voxel properties throughout is challenging due to the liquid creating a competing cooling and active absorbing components that effect the temperature of printed parts differently. Here, we balance fusibility by utilizing a thermal imaging and an agent loading sweep thermal profile characterization print for each individual agent. We then digitally control the agent loading based on this data set and dynamic thermal imaging to produce a uniform temperature profile. This ensures even fusing throughout multi-agent printed parts, shown by uniform weight measurements of multi-color cubes from average weight 1.4 ± 0.2 g to 1.5 ± 0.1 g.

null