APPLICATION AND PERFORMANCE EVALUATION FOR THE DMS SYSTEM IN THE SLS PROCESS

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1833-1838 ◽  
Author(s):  
DONG SOO KIM ◽  
SUNG WOO BAE ◽  
KYUNG HYUN CHOI
Keyword(s):  
Processing Time ◽  
Solid Freeform Fabrication ◽  
Selective Laser Sintering ◽  
Spot Size ◽  
Laser Sintering ◽  
Processing Efficiency ◽  
Freeform Fabrication ◽  
Beam Expander ◽  
Scan Path ◽  
And Performance

A Solid Freeform Fabrication (SFF) system using Selective Laser Sintering (SLS) is currently recognized as a leading process and SLS extends the applications to machinery and automobiles due to the various materials employed. Especially, accuracy and processing time are very important factors when the desired shape is fabricated with Selective Laser Sintering (SLS), one of Solid Freeform Fabrication (SFF) system. In the convectional SLS process, laser spot size is fixed during laser exposing on the sliced figure. Therefore, it is difficult to accuracy and rapidly fabricates the desired shape. In this paper, to deal with those problems a SFF system having ability of changing spot size is developed. The system provides high accuracy and optimal processing time. Specifically, a variable beam expander is employed to adjust spot size for different figures on a sliced shape. Therefore, design and performance estimation of the SFF system employing a variable beam expander are achieved and the mechanism will be addressed to measure the real spot size generated from the variable beam expander. Also, the reduction of total processing time is an important issue in SFF system. A digital mirror system (DMS) is a system which scans the laser beam with different spot size. The spot size is selected based on the slicing section to decrease and accuracy of the process time and improve the processing efficiency. In this study, the optimal scan path generation for DMS will be addressed, and this development will improve the whole processing efficiency and accuracy through the scan efficiency by considering the existing scan path algorithm and heat energy distribution.

Solid Freeform Fabrication of Ceramics Using Selective Laser Sintering and Selective Area Laser Deposition

1991 ◽  
Vol 249 ◽  
Author(s):  
Uday Lakshminarayan ◽  
Guisheng Zong ◽  
W. Richards Thissell ◽  
Harris L. Marcus
Keyword(s):  
Gas Phase ◽  
Solid Freeform Fabrication ◽  
Laser System ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Laser Deposition ◽  
Powder Materials ◽  
Freeform Fabrication ◽  
Selective Area

ABSTRACTSolid Freeform Fabrication (SFF) is a new computer fabrication technique that does not require any part specific tooling. The starting material can be either solid, liquid or gaseous. The part can be made from metallic, ceramic, polymeric or a composite material. The concept is to use a solid modeling system to define the part of interest and to reduce the model to a set of toggle point data that totally define the geometry. In Selective Laser Sintering the sectioned component is then combined with a rastered laser system that impinges on the precursor powder materials in a layered reconstruction of the three dimensional CAD designed part. The part is then formed in this manner. This approach to producing the part involves a great deal of understanding of the laser materials interactions, the appropriate choice of materials specific to this processing and how the total process integrates. Application to ceramic powders will be described. An alternative approach to SFF is Selective Area Laser Deposition where the three dimensional part is made from the gas phase. The initial gas deposition studies involving deposition of carbon from hydrocarbons will be discussed. For both of the above SFF approaches the laser beam powder and gas phase interactions and the microstructure of the resulting three dimensional forms as a function of system parameters will be described.

Development of Industrial SFF System Using a New Selective Dual-Laser Sintering Process

2006 ◽  
Vol 326-328 ◽  
pp. 123-126 ◽  
Author(s):  
Won Hee Lee ◽  
Dong Soo Kim ◽  
Young Jin Ahn ◽  
Byung Oh Choi ◽  
Kyung Hyun Choi
Keyword(s):  
Solid Freeform Fabrication ◽  
Laser System ◽  
Selective Laser Sintering ◽  
Great Influence ◽  
Laser Sintering ◽  
Beam Power ◽  
Sintering Process ◽  
Large Area ◽  
Freeform Fabrication ◽  
Dual Laser

In order to develop more elaborate and speedy system for large objects than existing selective laser sintering (SLS), this study applies a new selective dual-laser sintering process. It contains a 3-axis dynamic focusing scanner system for scanning large area instead of the existing fθ lens. As sintering parameters, the sintering temperature, the laser beam power and the layer thickness have a great influence on sintering of the polymer and metal powder. This paper will address the development of a solid freeform fabrication (SFF) system employing the dual laser system. Experiments were performed to evaluate the effect of a scanning path and to fabricate the large-sized object.

scholarly journals Advanced Trans-Tibial Socket Fabrication Using Selective Laser Sintering

2007 ◽  
Vol 31 (1) ◽  
pp. 88-100 ◽  
Author(s):  
Bill Rogers ◽  
Gordon W. Bosker ◽  
Richard H. Crawford ◽  
Mario C. Faustini ◽  
Richard R. Neptune ◽  
...  
Keyword(s):  
Solid Freeform Fabrication ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Structural Features ◽  
Laser Sintering ◽  
Health Science ◽  
Science Center ◽  
University Of Texas ◽  
Three Dimensional Objects ◽  
Prosthetic Socket

There have been a variety of efforts demonstrating the use of solid freeform fabrication (SFF) for prosthetic socket fabrication though there has been little effort in leveraging the strengths of the technology. SFF encompasses a class of technologies that can create three dimensional objects directly from a geometric database without specific tooling or human intervention. A real strength of SFF is that cost of fabrication is related to the volume of the part, not the part's complexity. For prosthetic socket fabrication this means that a sophisticated socket can be fabricated at essentially the same cost as a simple socket. Adding new features to a socket design becomes a function of software. The work at The University of Texas Health Science Center at San Antonio (UTHSCSA) and University of Texas at Austin (UTA) has concentrated on developing advanced sockets that incorporate structural features to increase comfort as well as built in fixtures to accommodate industry standard hardware. Selective laser sintering (SLS) was chosen as the SFF technology to use for socket fabrication as it was capable of fabricating sockets using materials appropriate for prosthetics. This paper details the development of SLS prosthetic socket fabrication techniques at UTHSCSA/UTA over a six-year period.

scholarly journals Investigation of fully dense laser sintering of tool steel powder using a pulsed Nd: Yag (neodymium-doped yttrium aluminium garnet) laser

2003 ◽  
Vol 217 (1) ◽  
pp. 127-138 ◽  
Author(s):  
W-N Su ◽  
P Erasenthiran ◽  
P M Dickens
Keyword(s):  
Tool Steel ◽  
Solid Freeform Fabrication ◽  
Single Layer ◽  
Steel Powder ◽  
Laser Sintering ◽  
Yttrium Aluminium Garnet ◽  
Freeform Fabrication ◽  
Yttrium Aluminium ◽  
Processing Step ◽  
Single Bead

A 550W neodymium-doped yttrium aluminium garnet (Nd:YAG) pulsed laser was used in the solid freeform fabrication (SFF) process to form fully dense sintered parts. Tool steel powder was chosen due to its wide acceptance in the tool-making industry. Unlike many processes applying either thermoplastic binder or metals of low melting points in the powder mixture, this process enables a direct fusion of material to solid parts without a further post-processing step. This paper presents a methodology and the results of high-power laser sintering of tool steel powder. The investigation includes the effects of various process parameters on the fully dense laser sintering results on a single bead and single layer and the related scan strategy to build up solid cubes. This process could eventually produce pre-forms with complex material structures rather than finished tools or parts.

Freeform Fabrication of High Performance Titanium Components via SLS/HIP

1998 ◽  
Vol 542 ◽  
Author(s):  
S. Das ◽  
J. J. Beaman ◽  
M. Wohlert ◽  
D. L. Bourell
Keyword(s):  
High Performance ◽  
Selective Laser Sintering ◽  
Hot Isostatic Pressing ◽  
Laser Sintering ◽  
Single Step ◽  
Isostatic Pressing ◽  
Freeform Fabrication ◽  
Post Process ◽  
Processed Material ◽  
Full Densification

AbstractThis paper presents the development of Selective Laser Sintering/Hot Isostatic Pressing (SLS/HIP) technology for production of functional high performance components in the titanium alloy Ti-6AI-4V. SLS/HIP is a net shape manufacturing technique that combines and exploits the freeform shaping capability of selective laser sintering and the full densification capability of hot isostatic pressing. The advantages of SLS combined with in situ HIP encapsulation include single step net shape canning, full densification by containerless HIP, no container-powder adverse interactions, reduced pre-processing time, and minimal post-process machining compared to conventional HIP of canned powders. Microstructure and mechanical properties of SLS processed and HIP post-processed Ti-6A1-4V are consistent with conventionally processed material. The potential of SLS/HIP technology was demonstrated by net shape fabricating a component to specification, namely the titanium guidance section housing base for the AIM-9 Sidewinder missile.

An Engineering Model for Laser-Induced Sintering of Polymer Powders

1999 ◽  
Vol 121 (3) ◽  
pp. 360-365 ◽  
Author(s):  
M. Kandis ◽  
C. W. Buckley ◽  
T. L. Bergman
Keyword(s):  
Laser Irradiation ◽  
Thermal Processing ◽  
Solid Freeform Fabrication ◽  
Selective Laser Sintering ◽  
Processing Parameters ◽  
Experimental Results ◽  
Porous Powder ◽  
Engineering Model ◽  
Freeform Fabrication ◽  
Polymer Powder

Laser-induced sintering of powders has become prevalent in a number of Solid Freeform Fabrication technologies such as Selective Laser Sintering (SLS), which is used to produce nearly solid parts from initially-porous powder via laser irradiation. In this paper, a model is presented which can be used to predict the shape and general features of consolidated heat affected zones produced by laser-induced, non-isothermal sintering of polymer powder. Comparisons between experimental results and predictions are made, and the model is used to investigate the influence of various thermal processing parameters on the sintering operation. The model is then extended to simulate the manufacture of a simple multiple layer part which is produced in a manner similar to SLS.

scholarly journals Impact of Laser Speed and Drug Particle Size on Selective Laser Sintering 3D Printing of Amorphous Solid Dispersions

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1149
Author(s):  
Rishi Thakkar ◽  
Miguel O. Jara ◽  
Steve Swinnea ◽  
Amit R. Pillai ◽  
Mohammed Maniruzzaman
Keyword(s):  
Particle Size ◽  
3D Printing ◽  
Solid Dispersions ◽  
Selective Laser Sintering ◽  
Amorphous Solid ◽  
Laser Sintering ◽  
Dosage Forms ◽  
Amorphous Solid Dispersions ◽  
Drug Particle ◽  
And Performance

This research demonstrates the influence of laser speed and the drug particle size on the manufacturing of amorphous solid dispersions (ASD) and dosage forms thereof using selective laser sintering 3-dimensional (3D) printing. One-step manufacturing of ASD is possible using selective laser sintering 3D printing processes, however, the mechanism of ASD formation by this process is not completely understood and it requires further investigation. We hypothesize that the mechanism of ASD formation is the diffusion and dissolution of the drug in the polymeric carrier during the selective laser sintering (SLS) process and the drug particle size plays a critical role in the formation of said ASDs as there is no mixing involved in the sintering process. Herein, indomethacin was used as a model drug and introduced into the feedstock (Kollidon® VA64 and Candurin® blend) as either unprocessed drug crystals (particle size > 50 µm) or processed hot-melt extruded granules (DosePlus) with reduced drug particle size (<5 µm). These feedstocks were processed at 50, 75, and 100 mm/s scan speed using SLS 3D printing process. Characterization and performance testing were conducted on these tablets which revealed the amorphous conversion of the drug. Both MANOVA and ANOVA analyses depicted that the laser speed and drug particle size significantly impact the drug’s apparent solubility and drug release. This significant difference in performance between formulations is attributed to the difference in the extent of dissolution of the drug in the polymeric matrix, leading to residual crystallinity, which is detrimental to ASD’s performance. These results demonstrate the influence of drug particle size on solid-state and performance of 3D printed solid dispersions, and, hence, provide a better understanding of the mechanism and limitations of SLS 3D printing of ASDs and its dosage forms.

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