2013 年 54 巻 630 号 p. 601-605
In orthopedic biomaterials, the advantages of porous metals are their improved fixation by bone tissue growing into metal pores and their low modulus resulting in stress shielding prevention. Among various fabrication techniques for porous materials, rapid prototyping is a prospective method of creating directly porous devices with controlled size in the form of a 3D structure. In this study, some types of Ti porous device composed of thin cell walls, which were analogous to human cancellous bone, were prepared by selective laser melting (SLM) and their compressive strength was evaluated in terms of cell wall thickness. A tensile test of a sheet formed by SLM was also carried out. The compressive strength of the porous device decreased with increasing bulk porosity. When the cell wall thickness was less than 1.0 mm, the strength of the device became markedly lower than that in the case of a thicker wall of the same bulk porosity. This is attributed to the decrease in the wall strength caused by incomplete melting at the surface.This speculation was confirmed by the observation that the tensile strength of a sheet decreased in proportion to sheet thickness.