Analysis of the cutting and stock removal mechanisms during grinding of ultra-hard cutting materials using polycrystalline boron nitride as an example

 

After diamond, polycrystalline cubic boron nitride (PCBN) is the second hardest known cutting material and is increasingly used in machining processes. PCBN is used in particular for cutting ferrous alloys, such as the nickel-based alloy Inconel® 718, with geometrically defined cutting edges, since diamond tools are unsuitable for these applications due to the carbon affinity of iron. The material-physical properties, such as the high hardness, of PCBN present the manufacturers of cutting tools with the challenge of making the production of high quality cutting tools economically viable. The grinding of PCBN plays a central role in the production chain of cutting tools as a finishing process. In order to reduce grinding wheel wear and thus improve the productivity of the PCBN grinding process, tribological investigations are carried out for the active partner combination of grinding wheel and PCBN workpiece.

The aim of the investigations is to gain knowledge about the thermo-mechanical load and to identify the cutting and grinding wheel wear mechanisms during the grinding of PCBN. Based on the results, a knowledge-based process design for the grinding of PCBN is enabled.