scholarly journals Indirect selective laser sintering of apatite—wollostonite glass—ceramic

2008 ◽  
Vol 222 (7) ◽  
pp. 1107-1114 ◽  
Author(s):  
K Xiao ◽  
K W Dalgarno ◽  
D J Wood ◽  
R D Goodridge ◽  
C Ohtsuki
Keyword(s):  
Glass Ceramic ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Biological Properties ◽  
Laser Sintering ◽  
Bending Test ◽  
Processing Route ◽  
Test Results ◽  
Infiltration Process ◽  
Three Point Bending

This paper develops an indirect selective laser sintering (SLS) processing route for apatite—wollastonite (A—W) glass—ceramic, and shows that the processing route, which can create porous three-dimensional products suitable for bone implants or scaffolds, does not affect the excellent mechanical and biological properties of the glass—ceramic. ‘Green parts’ with fine integrity and well-defined shape have been produced from glass particles of single-size range or mixed-size ranges with acrylic binder in various ratios by weight. A subsequent heat treatment process has been developed to optimize the crystallization process, and an infiltration process has been explored to enhance mechanical strength. Three-point bending test results show flexural strengths of up to 102 MPa, dependent on porosity, and simulated body fluid (SBF) tests show that the laser sintered porous A—W has comparable biological properties to that of conventionally produced A—W.

Manufacture and Characterisation of Bioceramic Tissue Engineering Scaffolds Produced by Selective Laser Sintering

2007 ◽  
Author(s):  
K. Xiao ◽  
J. A. Dyson ◽  
K. W. Dalgarno ◽  
P. Genever ◽  
D. J. Wood ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Selective Laser Sintering ◽  
Human Mesenchymal Stem Cells ◽  
Biological Properties ◽  
Laser Sintering ◽  
Process Conditions ◽  
Tissue Engineering Scaffolds ◽  
Process Maps ◽  
Bone Replacement ◽  
Porous Bioceramic

Currently there is no adequate bone replacement available that combines a long implant life with complete integration and appropriate mechanical properties. This paper reports on the use of human mesenchymal stem cells (MSCs) to populate porous bioceramic scaffolds produced by selective laser sintering (SLS) to create bespoke bioactive bone replacement structures. Apatite-wollastonite glass ceramic was chosen for use in this study because of its combination of excellent mechanical and biological properties, and has been processed using an indirect SLS approach. Process maps have been developed to identify process conditions for the SLS stage of manufacture and an optimised furnace cycle for the material has been developed to ensure that the required material phases for bioactivity are present in the manufactured scaffold. Results from tissue culture with the MSC’s on the scaffolds (using confocal and scanning electron microscopy) show that MSCs adhere, spread and retain viability on the surface, and penetrate into the pores of apatite wollastonite (A-W) glass ceramic scaffolds over a 21 day culture period. The MSC’s also show strong indications of osteogenesis, indicating that the MSC’s are differentiating to osteoblasts. These results indicate good biocompatibility and osteo supportive capacity of SLS generated A-W scaffolds and excellent potential in bone replacement applications.

Experimental and Numerical Investigation of Critical Buckle Load of Composite Specimens

2015 ◽  
Vol 732 ◽  
pp. 85-90
Author(s):  
Lukáš Bek ◽  
Radek Kottner ◽  
Jan Krystek ◽  
Tomáš Kroupa
Keyword(s):  
Static Analysis ◽  
Glass Fibre ◽  
Large Deformations ◽  
Bending Test ◽  
Test Results ◽  
Beam Test ◽  
Three Point Bending ◽  
Box Beams ◽  
Buckle Beam ◽  
Thin Walled

Different carbon and glass fibre strips were subjected to the double clamp buckle beam test. Furthermore, thin-walled glass fibre box-beams were subjected to the three-point bending test. Results of experiments were compared to different numerical simulations using buckling analysis or static analysis considering large deformations.

Cryogenic Interlaminar Properties of PBO Fiber/Epoxy Composites

2011 ◽  
Vol 391-392 ◽  
pp. 1445-1449
Author(s):  
Chun Hua Zhang ◽  
Shi Lin Luan ◽  
Xiu Song Qian ◽  
Bao Hua Sun ◽  
Wen Sheng Zhang
Keyword(s):  
Liquid Nitrogen ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Epoxy Composites ◽  
Bending Test ◽  
Test Results ◽  
Sem Images ◽  
Three Point Bending ◽  
Pbo Fiber ◽  
Interlaminar Shear

The influences of low temperature on the interlaminar properties for PBO fiber/epoxy composites have been studied at liquid nitrogen temperature (77 K) in terms of three point bending test. Results showed that the interlaminar shear strength at 77 K were significantly higher than those at room temperature (RT). For the analysis of the test results, the tensile behaviors of epoxy resin at both room temperature and liquid nitrogen temperature were investigated. The interface between fiber and matrix was observed using SEM images.

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.

Control-Oriented Modeling and Repetitive Control in In-Layer and Cross-Layer Thermal Interactions in Selective Laser Sintering

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Dan Wang ◽  
Tianyu Jiang ◽  
Xu Chen
Keyword(s):  
High Performance ◽  
Selective Laser Sintering ◽  
Repetitive Control ◽  
Three Dimensional ◽  
Process Variations ◽  
Laser Sintering ◽  
Laser Source ◽  
Cross Layer ◽  
Modeling And Control ◽  
Melt Pool

Abstract Although laser-based additive manufacturing (AM) has enabled unprecedented fabrication of complex parts directly from digital models, broader adoption of the technology remains challenged by insufficient reliability and in-process variations. In pursuit of assuring quality in the selective laser sintering (SLS) AM, this paper builds a modeling and control framework of the key thermodynamic interactions between the laser source and the materials to be processed. First, we develop a three-dimensional finite element simulation to understand the important features of the melt pool evolution for designing sensing and feedback algorithms. We explore how the temperature field is affected by hatch spacing and thermal properties that are temperature-dependent. Based on high-performance computer simulation and experimentation, we then validate the existence and effect of periodic disturbances induced by the repetitive in- and cross-layer thermomechanical interactions. From there, we identify the system model from the laser power to the melt pool width and build a repetitive control algorithm to greatly attenuate variations of the melt pool geometry.

Fabrication of Bioactive Glass-Ceramics by Selective Laser Sintering

2006 ◽  
Vol 309-311 ◽  
pp. 289-292
Author(s):  
Ruth D. Goodridge ◽  
Chikara Ohtsuki ◽  
Masanobu Kamitakahara ◽  
David J. Wood ◽  
Kenny W. Dalgarno
Keyword(s):  
Glass Ceramic ◽  
Selective Laser Sintering ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Laser Sintering ◽  
Layer Manufacturing ◽  
Custom Made ◽  
Good Potential

The feasibility of processing glass-ceramics using the layer manufacturing technique, selective laser sintering (SLS), to produce parts with suitable biological and mechanical properties for use in bone replacement applications, has been investigated. Glass-ceramics derived from glasses based on several different systems have been considered. Initial experiments using an apatite-mullite glass-ceramic (4.5SiO2⋅3Al203⋅1.6P2O5⋅3CaO⋅2CaF2) demonstrated the ability to process glass-ceramic materials using this technique, creating parts with a strength similar to that of cancellous bone, and a porous structure that was shown in vivo to be suitable for the ingrowth of bone. Concerns over the inability of the apatite-mullite material to form an apatite layer on its surface when soaked in a simulated body fluid (SBF) has led to the development of Al2O3-free glasses based on the systems (50-x)CaO⋅45SiO2⋅5P2O5⋅xCaF2 and (48-x)CaO⋅45SiO2⋅5P2O5⋅2CaF2⋅xNa2O. These materials have demonstrated good in vitro bioactivity, and therefore have good potential as candidates for processing by an indirect SLS method for the production of custom-made bone implants.

Dimensional error of selective laser sintering, three-dimensional printing and PolyJet™ models in the reproduction of mandibular anatomy

2009 ◽  
Vol 37 (3) ◽  
pp. 167-173 ◽  
Author(s):  
Danilo Ibrahim ◽  
Tiago Leonardo Broilo ◽  
Claiton Heitz ◽  
Marília Gerhardt de Oliveira ◽  
Helena Willhelm de Oliveira ◽  
...  
Keyword(s):  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Dimensional Error ◽  
Three Dimensional Printing ◽  
Dimensional Printing

Three-Dimensional Modeling of Selective Laser Sintering of Two-Component Metal Powder Layers

2005 ◽  
Vol 128 (1) ◽  
pp. 299-306 ◽  
Author(s):  
Tiebing Chen ◽  
Yuwen Zhang
Keyword(s):  
Metal Powder ◽  
Continuous Wave ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Powder Layer ◽  
Metal Powders ◽  
Gaussian Laser Beam ◽  
Scanning Velocity ◽  
Three Dimensional Modeling

Laser sintering of a metal powder mixture that contains two kinds of metal powders with significantly different melting points under a moving Gaussian laser beam is investigated numerically. The continuous-wave laser-induced melting accompanied by shrinkage and resolidification of the metal powder layer are modeled using a temperature-transforming model. The liquid flow of the melted low-melting-point metal driven by capillary and gravity forces is also included in the physical model. The numerical results are validated by experimental results, and a detailed parametric study is performed. The effects of the moving heat source intensity, the scanning velocity, and the thickness of the powder layer on the sintering depth, the configuration of the heat affected zone, and the temperature distribution are discussed.

Effect of Alkaline Treatment of Wood Flour on Strength of Wood-Plastic Composites for Selective Laser Sintering

2010 ◽  
Vol 136 ◽  
pp. 131-134 ◽  
Author(s):  
Kai Yi Jiang ◽  
Y.L. Guo ◽  
W.L. Zeng ◽  
Z.S. Xin ◽  
X. Liu
Keyword(s):  
Mechanical Property ◽  
Bonding Strength ◽  
Wood Flour ◽  
Selective Laser Sintering ◽  
Performance Testing ◽  
Alkaline Treatment ◽  
Laser Sintering ◽  
Test Results ◽  
Shock Strength ◽  
Plastic Composites

Based on selective laser sintering of rapid prototyping process, the composites were prepared by filling PES with wood flour. For enhancing the affinity of high polar wood flour and non polar PES, and improving the bonding strength, the wood flour was modified via alkalinization. This paper studied the effects of adding compatibilizer and alkaline treatment on the forming accuracy and mechanical property of WPC. The test results show alkaline treatment decreased the hydrophilicity of wood flour, increased the contact area between PES and wood flour and improved the bonding strength. Adding the compatibilizer polypropylene grafting maleic anhydride (PP-g-MAH) can form bonds between the wood flour PES and PP which improves their compatibility and mechanical property more. After performance testing, the relative warping rate is only 0.26%, the tensile strength is 0.014MPa, and shock strength is 0.954KJ/m2.

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