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Full-Text Articles in Mechanical Engineering
A Novel Extrusion-Based Additive Manufacturing Process For Ceramic Parts, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Greg Hilmas
A Novel Extrusion-Based Additive Manufacturing Process For Ceramic Parts, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An extrusion-based additive manufacturing process, called the Ceramic On-Demand Extrusion (CODE) process, for producing three-dimensional ceramic components with near theoretical density is introduced in this paper. In this process, an aqueous paste of ceramic particles with a very low binder content ( < 1 vol%) is extruded through a moving nozzle at room temperature. After a layer is deposited, it is surrounded by oil (to a level just below the top surface of most recent layer) to preclude non-uniform evaporation from the sides. Infrared radiation is then used to partially, and uniformly, dry the just-deposited layer so that the yield stress of the paste increases and the part maintains its shape. The same procedure is repeated for every layer until part fabrication is completed. Several sample parts for various applications were produced using this process and their properties were obtained. The results indicate that the proposed method enables fabrication of large, dense ceramic parts with complex geometries.
3d Printing Of A Polymer Bioactive Glass Composite For Bone Repair, Caroline Murphy, Krishna C. R. Kolan, M. Long, Ming-Chuan Leu, Julie A. Semon, D. E. Day
3d Printing Of A Polymer Bioactive Glass Composite For Bone Repair, Caroline Murphy, Krishna C. R. Kolan, M. Long, Ming-Chuan Leu, Julie A. Semon, D. E. Day
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A major limitation of synthetic bone repair is insufficient vascularization of the interior region of the scaffold. In this study, we investigated the 3D printing of adipose derived mesenchymal stem cells (AD-MSCs) with polycaprolactone (PCL)/bioactive glass composite in a single process. This offered a three-dimensional environment for complex and dynamic interactions that govern the cell’s behavior in vivo. Borate based bioactive (13-93B3) glass of different concentrations (10 to 50 weight %) was added to a mixture of PCL and organic solvent to make an extrudable paste. AD-MSCs suspended in Matrigel was extruded as droplets using a second syringe. Scaffolds measuring …
Designed Extrudate For Additive Manufacturing Of Zirconium Diboride By Ceramic On-Demand Extrusion, Devin Mcmillen, Wenbin Li, Ming-Chuan Leu, Greg Hilmas, Jeremy Lee Watts
Designed Extrudate For Additive Manufacturing Of Zirconium Diboride By Ceramic On-Demand Extrusion, Devin Mcmillen, Wenbin Li, Ming-Chuan Leu, Greg Hilmas, Jeremy Lee Watts
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This work describes a process by which zirconium diboride (ZrB2) parts may be fabricated using the Ceramic On-Demand Extrusion (CODE) process. An oxide-carbide-nitride system consisting of ceramic powders and pre-ceramic organics, designed to yield ZrB2 after reaction sintering, has been developed to produce an aqueous-based extrudate for subsequent processing in the CODE system. Pressurelessly sintered test specimens containing 1 wt% PVA binder achieve high relative density ≥ 99%. The viscoelastic response of the extrudate was characterized via spindle rheometry with a small sample adapter. Batches with 1 wt% PVA and 0.5 wt% Methocel show strong shear thinning characteristic, under …
Novel Extrusion-Based Additive Manufacturing Process For Ceramic Parts, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Greg Hilmas
Novel Extrusion-Based Additive Manufacturing Process For Ceramic Parts, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Greg Hilmas
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An extrusion-based additive manufacturing process, called the Ceramic On-Demand Extrusion (CODE) process, for producing three-dimensional ceramic components with near theoretical density is introduced in this paper. In this process, an aqueous paste of ceramic particles with a very low binder content (< 1 vol%) is extruded through a moving nozzle at room temperature. After a layer is deposited, it is surrounded by oil (to a level just below the top surface of most recent layer) to preclude non-uniform evaporation from the sides. Infrared radiation is then used to partially, and uniformly, dry the just-deposited layer so that the yield stress of the paste increases and the part maintains its shape. The same procedure is repeated for every layer until part fabrication is completed. Several sample parts for various applications were produced using this process and their properties were obtained. The results indicate that the proposed method enables fabrication of large, dense ceramic parts with complex geometries.
Properties Of Partially Stabilized Zirconia Components Fabricated By The Ceramic On-Demand Extrusion Process, Wenbin Li, Amir Ghazanfari, Devin Mcmillen, Ming-Chuan Leu, Greg Hilmas, Jeremy Lee Watts
Properties Of Partially Stabilized Zirconia Components Fabricated By The Ceramic On-Demand Extrusion Process, Wenbin Li, Amir Ghazanfari, Devin Mcmillen, Ming-Chuan Leu, Greg Hilmas, Jeremy Lee Watts
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Ceramic On-Demand Extrusion (CODE) process is a novel additive manufacturing process for fabricating dense ceramic components from aqueous pastes of high solids loading. In this study, 3 mol% Y2O3 stabilized tetragonal zirconia polycrystal (3Y-TZP) parts were fabricated using the CODE process. The parts were then dried in a humidity controlled environmental chamber and sintered under atmospheric pressure. Mechanical properties of the sintered parts were examined using ASTM standard test techniques, including density, Young’s modulus, flexural strength, Weibull modulus, fracture toughness and Vickers hardness. The microstructure was analyzed, and grain size was measured using scanning electron microscopy. …