In this paper, patent trend on the rapid prototyping technologies is analyzed. The results show that USA has the most patents, the largest citations, and the highest CPP(Citations Per Patent) at the rapid prototyping field, and that 3D SYSTEM in USA has the most patent filings among the whole world company. and STRATASYS in USA is ranked with the highest CPP representing a technology impact in that field. It is shown that molding or bonding technology of plastic is occupied 31% by International Patent Classification Index(IPC).

A new approach to sintering loose packed, coarse aluminum alloy powder to full or near full density is presented. A controlled amount of water vapor is introduced into the sintering atmosphere, which disru pts the oxide film and allows metallurgical contact between particles. In addition, supersolidus liquid phase sintering is used to sinter the part to full density. Since the method is particularly applicable to uncompacted powders, it is potentially useful for sintering aluminum powder preforms manufactured by 3DPrinting and powder injection molding.