HARD MILLING OF POWDER METALLURGICAL STEEL FOR PUNCHES -POTENTIALS AND LIMITATIONS FOR COMPLETE MANUFACTURING

摘要

Tool makers are seeking competitive advantage through complete hard cutting of tools. Hard milling takes centre stage in this discussion, since the question of process selection, i.e. milling versus spark erosion machining, comes up daily depending on the part configuration. With increasing material hardness and workpiece complexity, it becomes evident that there is a critical linkage between the milling processes with regard to NC-programming and milling strategies as well as tool manufacturing technology. Hard cutting processes for the tool manufacturing industry bear many chances for reduction of costs and lead time. The potential depends on the complete integration of the process components and the further optimization of the process chain. Powder metallurgical steels offer large potential for tool and mould manufacturing due to higher process performance. However, the knowledge of machining powder metallurgical steels in their hardened state is limited. At Fraunhofer IPT the technology of hard milling powder metallurgical steel (CPM9V) was investigated in comparison to conventional D2 steel. This paper describes fundamental cutting mechanism for hardened steels, results from FEM-simulations, hard milling with coated full carbide tools, CAM-machining strategies, application examples and economic benefits.