Research on Electrical Discharge Grinding Technics and Tool's Life of Polycrystalline Cubic Boron Nitride Cutting Tool

摘要

Electrical discharge grinding is part of the most widely used methods to machine polycrystalline cubic boron nitride cutting tools. Polycrystalline cubic boron nitride compact samples at different granularity size are the research object. Electrode running speed, peak current and pulse duration is selected as the main process parameters. Material removal volume and the electrode wear set as the evaluation index of productive efficiency. Workpiece surface roughness value sets as an evaluation standard of processing quality. Through electrical discharge grinding experiments, combined with scanning electron microscopy observation, energy spectrum analyzer and roughness tester, the influences of the main process parameters on electrical discharge grinding are analyzed, results show that polycrystalline cubic boron nitride crystal granularity size has some effect on the electrical discharge grinding. With the increase of the electrode rotation speed, the workpiece material removal volume is increased, but the increase rate becomes slow. Electrode wear is further increased with the increase of the electrode rotation speed. With the peak current increase, material removal volume and the surface roughness value of the workpiece material increase, electrode wear reduces. Through the turning test, the relationship between service life of polycrystalline cubic boron nitride cutting tools that are machined by electrical discharge grinding and cutting tool flank wide, workpiece surface roughness are discussed. The results showed that to adjust electrical discharge grinding parameter, such as pulse duration and machining electric currents, can reduce the depth of the effect layer and extend the service life of polycrystalline cubic boron nitride cutting tool. The research provides a valuable experimental reference for drawing up electrical discharge grinding technics of polycrystalline cubic boron nitride cutting tool.