Design and Rapid Fabrication of Non-assembly Mechanisms

Abstract

Layer based rapid fabrication technologies have seen rapid progress in recent years in terms of both material choices and part accuracy. Given the great progress, such technologies still have difficulties in meeting the accuracy requirements of functional parts such as mechanisms with joints. In mechanism fabrication, one of the critical factors is the joint clearance. With the limited accuracy of current layer based fabrication technologies, only mechanism joints with large clearance could be made. Thus how to reduce the joint clearance is a major research issue for layer based rapid fabrication of non-assembly mechanisms. In this paper, both joint design (revolute pin joint only) and process control will be analyzed in order to fabricate non-assembly mechanisms with a minimum joint clearance. In order to demonstrate the usefulness of non-assembly mechanisms, metal parts are fabricated by selective laser melting. Such parts have the strength that can stand the load in actual operations.