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Full-Text Articles in Manufacturing
Probabilistic Simulation Of Solidification Microstructure Evolution During Laser-Based Metal Deposition, Jingwei Zhang, Frank W. Liou, William Seufzer, Joseph William Newkirk, Zhiqiang Fan, Heng Liu, Todd E. Sparks
Probabilistic Simulation Of Solidification Microstructure Evolution During Laser-Based Metal Deposition, Jingwei Zhang, Frank W. Liou, William Seufzer, Joseph William Newkirk, Zhiqiang Fan, Heng Liu, Todd E. Sparks
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A predictive model, based on a Cellular Automaton (CA) - Finite Element (FE) method, has been developed to simulate microstructure evolution during metal solidification for a laser based additive manufacturing process. The macroscopic FE calculation was designed to update the temperature field and simulate a high cooling rate. In the microscopic CA model, heterogeneous nucleation sites, preferential growth orientation and dendritic grain growth kinetics were simulated. The CA model was able to show the entrapment of neighboring cells and the relationship between undercooling and the grain growth rate. The model predicted the dendritic grain size, structure, and morphological evolution during …
Effect Of Architecture And Porosity On Mechanical Properties Of Borate Glass Scaffolds Made By Selective Laser Sintering, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Taylor Comte
Effect Of Architecture And Porosity On Mechanical Properties Of Borate Glass Scaffolds Made By Selective Laser Sintering, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Taylor Comte
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The porosity and architecture of bone scaffolds, intended for use in bone repair or replacement, are two of the most important parameters in the field of bone tissue engineering. The two parameters not only affect the mechanical properties of the scaffolds but also aid in determining the amount of bone regeneration after implantation. Scaffolds with five different architectures and four porosity levels were fabricated using borate bioactive glass (13-93B3) using the selective laser sintering (SLS) process. The pore size of the scaffolds varied from 400 to 1300 μm. The compressive strength of the scaffolds varied from 1.7 to 15.5 MPa …
Effect Of Particle Size, Binder Content And Heat Treatment On Mechanical Properties Of 13-93 Bioactive Glass Scaffolds, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Mariano Garcia Velez
Effect Of Particle Size, Binder Content And Heat Treatment On Mechanical Properties Of 13-93 Bioactive Glass Scaffolds, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Mariano Garcia Velez
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Particle size, binder content and the post-processing schedule are important parameters that affect the microstructure, and, hence, the mechanical properties of parts produced using the indirect selective laser sintering process. 13-93 bioactive glass, with mean particle sizes ranging from 10 μm to 44 μm, is mixed with different amounts of stearic acid binder to fabricate green scaffolds. Through the design of the post-processing schedule, the time required for postprocessing the green scaffolds is reduced from the initial 80 hrs to 12 hrs. The compressive strength varies from 41 MPa for a part with~60% porosity to 157 MPa for a part …
Optimization Of Selective Laser Sintering Process For Fabrication Of Zirconium Diboride Parts, Ming-Chuan Leu, Shashwatashish Pattnaik, Greg Hilmas
Optimization Of Selective Laser Sintering Process For Fabrication Of Zirconium Diboride Parts, Ming-Chuan Leu, Shashwatashish Pattnaik, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Selective Laser Sintering (SLS) was investigated to fabricate Zirconium Diboride (ZrB2) parts for ultra-high temperature applications. Experiments were conducted to determine values of SLS process parameters (laser power, scan speed, line spacing, and layer thickness) that can be used to build ZrB2 parts with high integrity and sharp geometrical features. A sacrificial plate with a proper number of layers (determined from experimentation) separated from the main part was built in order to reduce thermal gradients when building the main part. The sacrificial plate was found to assist in eliminating cracks in the bottom of the main part. …
Selective Laser Sintering Of 13-93 Bioactive Glass, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Mariano Garcia Velez
Selective Laser Sintering Of 13-93 Bioactive Glass, Krishna C. R. Kolan, Ming-Chuan Leu, Greg Hilmas, Mariano Garcia Velez
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Bioactive glasses are more promising than biopolymers in fabricating scaffolds for bone tissue repair because they convert to hydroxyapatite, when implanted in vivo. Both direct and indirect selective laser sintering (SLS) methods of 13-93 bioactive glass were considered in this research to study the feasibility of fabricating scaffolds for bone repair applications. Stearic acid was used as the binder in the indirect method to fabricate the scaffolds. The green scaffolds underwent binder burnout and sintering at various soaking conditions between 675⁰C and 700⁰C, achieving a maximum compressive strength of 23.6 MPa, which is higher than that of the human cancellous …