Potentials of Dry Rotary Swaging

Infeed rotary swaging is an appropriate cold massive forging technology for the manufacture of cylindrical shaped components made of iron or aluminum base alloys. The process is focused on reducing the cross-section of full profiles or tubes and is e.g. widely used in automotive industry. The design of swaged hollow components can easily be adapted to the external load in such a way, that the wall thickness is partially reduced and the material cross-section is increased where needed. The above-mentioned advantages result in a high potential for light-weight production while the produced components exhibit high geometric accuracy and surface quality. However, an excellent CO2 balance is yet limited due to high demands for lubricants significantly increasing the number of process steps for further component refinement.
In order to increase the overall process efficiency, a changeover to a dry process design becomes necessary. A dry processing will cause high die wear and deterioration of workpiece quality. The most important functions of the lubricant have to be substituted by other approaches and strategies. Development and removal of heat, generation and discharge of wear debris and, above all, die wear and the resulting workpiece quality have to be considered. The effective tribological friction conditions have to be adjusted by means of geometric adaptations of the active die surfaces to realize good workpiece qualities at comparable cycle times.
This paper gives a review of the state-of-the-art in dry rotary swaging. Extensive experiments in laboratory scale as well as application tests were performed with various die setups. The most important findings regarding wear, wear minimization, process kinematics, workpiece quality, FEM simulation are presented. The overarching goal is to achieve a longterm stability for the successful dry processing.