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).

This paper deals with selecting an optimal rapid prototyping(RP) machine that suits the end use of a part. Evaluation factors include only major attributes such as accuracy, roughness, strength, part cost and build time that greatly affect the performance of RP machines. Accuracy, surface roughness and strength are presented as crisp values. The part cost and build time identified as just approximate ranges due to different human cost and many variable parameters are presented by linguistic values. It can be described with triangular fuzzy numbers. Based on the evaluation values obtained, an appropriate RP process for a specific part application can be selected by using the modified TOPSIS(Technique of Order Preference by Similarity to Ideal Solution) method including crisp data as well as linguistic variables, and each weight on the alternatives is assigned by using a fuzzy weight. The ranking order of all machines provides the decision information for the selection of RP machines.