Mechanical Fastener Designs for Use in the Microassembly of 3D Microstructures

Abstract

This paper describes micro-mechanical fastener designs used to create joints between surface micromachined micro-parts. This is part of ongoing research to develop a general microassembly system capable of assembling various types of microstructures. The microassembly system is based on sequential robotic operations and the use of a microgripper. Two new joint designs referred to as ‘key-lock’ joints and ‘inter-lock’ joints are introduced. Key-lock joints are created by the insertion of a ‘key’ on one micro-part, into a mating slot on another micro-part. By translating the first micro-part within the other, after the key is inserted, it becomes locked into position. Inter-lock joints are created by the perpendicular insertion of one micro-part with a slit, into another micro-part with a slit. The slits create an interference fit and are permanent once the micro-parts are joined. The design of these joints and the experimental results are detailed. In addition, ongoing work involving recent ‘snap-lock’ joint fastener designs is described. This includes an example of a 3D micro-transformer and a stacked microstructure. These various micro-mechanical fasteners demonstrate a number of ways in which micro-parts can be assembled into 3D microstructures.