Full-Densification of SLS Parts by Re-Melting

Among commercially available rapid prototyping processes, SLS is the most effective in terms of adaptability of various materials. However, rapid prototyped parts by the process are always porous and the physical properties of the parts are different from dense parts which is to be used in final product. This paper introduces a post process that can densify SLS processed plastic parts to almost 100%. An SLS processed polystyrene part is densified and, resultantly, a much stronger and transparent part is obtained.Mechanical Engineerin

Transparentization of SLS Processed SMMA Copolymer Parts by Infiltrating a Thermosetting Epoxy Resin with Tuned Refractive Index

Selective laser sintering is quite advantageous to build complicated tubular structures such as intake manifolds of automotive engines because of its ability of building undercut structures without using support ribs. On the other hands, inevitable opacity of the parts obtained from the process is lowering its advantage when we need to observe inside of the parts. A technology that can transparentize SLS processed parts by infiltrating curable resin with tuned refractive index was introduced by the authors in 2004, and in this paper, several modifications are added on material, process parameters and their control accuracies to improve clarity of obtained parts. As a result of these modifications, haze of the processed part was reduced by a factor of 40% reaching the lowest value of 20% through a plate with thickness of 5mm.Mechanical Engineerin

Preliminary Study for Transparentization of SLS Parts by Resin Infiltration

Since opacity of SLS processed parts are derived from random reflection and refraction at boundaries of refractive indices between the air and plastic, infiltration of resin that shares the same index with the plastic can increase transparency of the parts. In this paper, desirable characteristics for the infiltrant were investigated first, and transparentization test of SLS processed parts out of CastFormTM was carried out. The highest transmittance of 80% and the lowest haze of 55% were obtained. However, exact match of refractive indices of powder for SLS and infiltrant did not give the best transparency. The reasons were considered in discussions.Mechanical Engineerin

Effective Mechanisms of Multiple LED Photographic Curing

Multiple LED Photographic Curing (MPC) has proven capable of drawing cross sections of three-dimensional objects like printing a sheet of paper. Using raster scanning, however, simultaneously exposing a photopolymer with 1,024 beams of light involves various unknown issues. The aim of this research work was to examine the formation of individual strings and the connecting mechanisms between strings and layers. At light power ranging from 19.0 to 30.3flW and at various scan speeds, string formation perpendicular to scan direction differs greatly from that in scan direction. Curing of plane layers happens by curing strings side-by-side with a constant spacing of 62.5flm.Mechanical Engineerin

Laser Sintering Fabrication of Highly Porous Models Utilizing Water Leachable Filler-Experimental Investigation into Process Parameters

The authors are developing a laser sintering process to fabricate highly porous models with such high porosities as 90% and more. In the process, water-soluble filler is mixed with designated plastic powder and leached out after laser sintering process is finished to generate pores where the grains used to exist. Previously, the authors reported successful application of this technology on a tissue engineering scaffold. However, relationship between process parameters and obtained results has not been clarified. This paper reports experimental investigation into effects of optimizing process parameters such as mixture, grain size of the filler on resultant porosity, pore size and process resolutionMechanical Engineerin