Some of the most important steps in manufacturing microelectromechnical systems (MEMS) are their assembly and handling. With handling we mean the way we can safely, without damages, pick microparts of any shape or any kind of material, rotate them to the desired orientation and finally position them precisely on or connect them with other microparts. For these purposes, specially designed tools – microgrippers – are required. This paper presents the design, development, fabrication method using the SU8 technology and post-fabrication processes with the goal to obtain a new type of micro-gripper. This micro-gripper was produced for a handling and assembly station developed at the IMFT (TU Wien). To investigate the obtained structures we performed a "quality inspection" and a calibration of the gripper parameters. These investigations gave an important insight on such parameters as technology accuracy, parameter settings for the SU8 technology, the obtained properties of the structure and the functional features (elasticity and applied force). Based on this, possibilities for further quality improvements have been considered.
Two mechanical gripper types have been designed. Using a technology selection method, EDM was selected as the most appropriate fabrication technology for the designed grippers. Prototypes have been fabricated by wire EDM on a conventional machine. Increased attention has been paid to methodology of the production process and exploration of (mu) -EDM possibilities. The tolerance obtained is about 1 micrometers . The accuracy of the machined product is mainly determined by the quality of the electrode, its handling and the adjustment procedures. After fabrication the grippers were integrated onto a station for handling and assembly of microstructures. This paper provides a description of the used methodology in the production sequence and information on the machining process of the whole gripping system (gripper, holder, arrow). The results after the production are tested, analyzed and discussed.
Nowadays the application of specially designed grippers in micro technology is an important topic and a necessity for the industrialisation. In order to transfer the manual assembly of micro electro mechanical system (MEMS) to an automatic assembly process, specially designed handling tools with sensing capabilities are required. Keeping the dimensions of the microparts in mind the handling and assembly process requires supervision with microscopes, positioning with high precision and application of specially designed tools. This paper describes a miniaturised mechanical gripper system with specially designed grippers and with implemented force-feedback for general microassembly purpose. The described grippers are fabricated from spring steel by wire electro-discharge-machining (EDM). The design of the microgripping system allows handling of pieces with sizes from 10 micrometers up to 2 mm.
Handling, assembly and testing in the micro-scale is an important research area. The solutions on how to handle and assemble microparts mainly smaller than the dot on the 'i' in this text can only be achieved by an international consortium of partners, each having large experience and expertise in different but complementary technical or scientific fields, with the industry and partners with commercial activities in the background taking an active role by providing directions according to their requirements. This paper describes some scientific highlights and training activities of HAFAM (Full title: Handling and Assembly of Functionally Adapted Microcomponents), a European network within the EC Programme 'Training and Mobility of Researchers.'