Lehrstuhl für Fertigungstechnologie, Universität Erlangen-Nürnberg

Cold Metal Forming of Microparts - Material Behavior, Friction, Process Design

Datum: 04.12.1997



  • Prof. Dr.-Ing. Dr. h.c. M . Geiger
  • Prof. Dr.-Ing. Dr. h.c. M . Geiger

Microparts with a wide variety of shapes and functions are used in large numbers in the fields of electronic production and micro mechanics. The production of those parts by means of metal forming has several advantages compared to alternative manufacturing methods. The aim of this project was to transfer the process knowledge from conventional metal forming to microforming, thus establishing guidelines for process design. In order to determine size dependent effects on metal forming behavior, basic tests like tension, upsetting and ring upsetting experiments were performed, using scaled specimen, ranging from macro to micro dimensions. Significant size effects could be found, which result mainly from the fact that microstructure and surface topography do not change with part dimensions. Based on these findings models were developed to describe the miniaturization effects on friction and material behavior. Furthermore, these models were implemented into existing FEM software to provide the basis for size dependent numerical simulation. Finally, the experimental findings from the previously performed basic test were verified for a more complex process, the solid forward extrusion. As before, also the extrusion process was performed with scaled specimen and scaled tooling. The smallest of these tools produces a part with a diameter of 0.3 mm, starting from a billet of 0.5 mm diameter and represents the worlds smallest extrusion tool.