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Prototyping Method (prototyping + method)

Distribution by Scientific Domains
Polymers and Materials Science100%

Kinds of Prototyping Method

  • rapid prototyping method
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    Selected Abstracts

    Analysis of the mechanical behavior of a titanium scaffold with a repeating unit-cell substructure

    JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009
    Garrett Ryan
    Abstract Titanium scaffolds with controlled microarchitecture have been developed for load bearing orthopedic applications. The controlled microarchitecture refers to a repeating array of unit-cells, composed of sintered titanium powder, which make up the scaffold structure. The objective of this current research was to characterize the mechanical performance of three scaffolds with increasing porosity, using finite element analysis (FEA) and to compare the results with experimental data. Scaffolds were scanned using microcomputed tomography and FEA models were generated from the resulting computer models. Macroscale and unit-cell models of the scaffolds were created. The material properties of the sintered titanium powders were first evaluated in mechanical tests and the data used in the FEA. The macroscale and unit-cell FEA models proved to be a good predictor of Young's modulus and yield strength. Although macroscale models showed similar failure patterns and an expected trend in UCS, strain at UCS did not compare well with experimental data. Since a rapid prototyping method was used to create the scaffolds, the original CAD geometries of the scaffold were also evaluated using FEA but they did not reflect the mechanical properties of the physical scaffolds. This indicates that at present, determining the actual geometry of the scaffold through computed tomography imaging is important. Finally, a fatigue analysis was performed on the scaffold to simulate the loading conditions it would experience as a spinal interbody fusion device. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2009 [source]

    Fabrication of Millimeter-Wave Electromagnetic Bandgap Crystals Using Microwave Dielectric Powders

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2009
    Xuesong Lu
    Electromagnetic bandgap (EBG) structures active in the 90,110 GHz region widely used by security imaging radar were created using different ceramics by a rapid prototyping method informed by finite difference time domain modeling. This solid free-forming method uses a high volatility solvent-based ceramic paste extruded through fine nozzles allowing ceramic powders to be assembled on a multiaxis building platform avoiding machining, etching, or the alignment of loose rods and created to designs downloaded directly from a computer file. Lattices were made from two high dielectric constant ceramics: La(Mg0.5, Ti0.5)O3 and (Zr0.8, Sn0.2)TiO4 and compared with those of Al2O3 demonstrating three EBG structures with different dimensions and dielectric constants but with the same bandgap. The effects of manufacturing tolerances on bandgap frequency are investigated by simulation. [source]

    Rapid Prototyping of Piezoelectric Ceramics via Selective Laser Sintering and Gelcasting

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2004
    Dong Guo
    This article presents a new lost mold rapid prototyping method which combines selective laser sintering (SLS) and gelcasting techniques for fabricating piezoelectric ceramics. SLS was used to fabricate sacrificial molds of the desired structure of the ceramic part. Then aqueous PZT (lead zirconate titanate) suspension was cast in the mold and solidified in situ through formation of a three-dimensional network gel. Because the polymer mold can be easily removed at the initial stage of sintering and the gelcast PZT body has a high green strength, the desired geometry of the PZT part can be completely retained after sintering of the ceramics. Complex-shaped PZT parts were successfully fabricated after using concentrated PZT suspension with low viscosity. Densities and electrical properties, such as the d33, the relative permittivity ,, the dielectric loss tg, and the electromechanical coupling factor Kp of the gelcast PZT parts were also compared with those of the die-pressed PZT samples. The results indicated that the gel-forming process did not deteriorate the electrical properties of the samples, if proper dispersant was selected in developing concentrated ceramic slurry. [source]

    Fabrication of Ceramic,Polymer Photonic Crystals by Stereolithography and Their Microwave Properties

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2002
    Soshu Kirihara
    Three-dimensional photonic crystals with periodic variations in the dielectric constant were fabricated using a stereolithographic rapid prototyping method. The structures were composed of millimeter-scale ordered epoxy lattices in which ceramic particles with high dielectric constants (such as silica and titania) were dispersed. These crystals were designed to reflect microwaves via the formation of photonic band gaps in a gigahertz range. The attenuation of transmission amplitude through the photonic crystals, which was measured as a function of frequency using a network analyzer, clearly showed the formation of band gaps in the microwave range. [source]