Chip formation in machining metal bonded grinding layers

Abstract

Gears demand increasingly high quality regarding acoustic emissions, surface roughness and lifetime. Therefore, grinding is often the last step in the process chain of gear manufacturing. Grinding wheel grain sizes of 30 micrometers lead to high surface quality and metal bonded CBN-grains allow a high wear resistance and profile stability of the grinding tool. Consequently, an increase of the material removal rates and thus productivity is possible without increasing the thermal load on the workpiece due to the grinding wheels' high thermal conductivity. However, the time and cost intensive dressing process in combination with the high profile requirements for gear grinding prevent the wide application of metal bonded tools for this application. This challenge can be solved using a new dressing approach with geometrically defined cutting edges. Metal bonded CBN-grinding layers have a structure similar to metal-matrix-composites, which can be machined by using the turning operation. The aim of this work is to verify the machinability of metal bonded CBN-grinding layers. In the present work, the chip formation for metal bonded grinding layers is presented.