Micro forming with local part heating by laser irradiation in transparent tools

R. Erhardt, F. Schepp, D. Schmoeckel

Institute for Production Engeneering and Metal Forming Machines, Darmstadt University of Technology, Germany

At present, the production of micro-technical parts with metal material in large scale manufacturing is made either by means of lithographic procedures and subsequent etching or galvanic building-up or by stamping and forming procedures. However, economical stamping and forming procedures are subject to strict limits with an aspect ratio from 1.5 - 2 at present.
Therefore, the process limitations of the microforming technology and thus the part spectrum of the micro parts manufactured by forming technology will be considerably extended in a current research project. In contrast to the existing technology, the idea is that the forming should take place locally as half-warm and warm forming respectively. By the use of transparent tool inserts, e.g. made of diamond or sapphire, the heating of the workpiece zones can take place within the closed tool by laser irradiation. Thus the material can be warmed up directly in the forming zone. With this method, only high strain areas are partially warmed up. To achieve high temperatures and short cycle times Nd:YAG lasers or diode lasers are used.
Aim of the project is the development of a procedure and a tool technology for laser-supported forming, as well as the creation of a technology base for the later conversion of the micro forming in the manufacturing process. The processes to be researched are those of micro deep drawing and micro indirect impact extrusion.
This paper aims at explaining the project idea, as well as presenting first research results and basic studies for laser-supported micro-forming.

Keywords: Microforming, heating by laser irradiation, transparent tools, halfwarm forming