Experimental Study On WEDM Machining Of PCD And PCBN Compacts

With the rapid development of CNC machining technology and the widespread applications of the numerical control machines, superhard material tools is playing a more and more important role in industry. In all of the superhard materials, PCD and PCBN compacts are the most popular, but the method to machine these compacts efficiently and high-precisionly is one of the difficulties in the industry. WEDM is used to cut compacts mainly; its processing efficiency and quality can make a greater impact in PCD, PCBN cutting tools manufacture. So how to improve the processing efficiency and quality is expected. Therefore, it has great application value and theoretical significance to research the machining of PCD and PCBN compacts, develop the appropriate process conditions and explore the process mechanism using Low-Speed WEDM.Firstly, four kinds of typical materials, CTH025, CTB010, BNX20and BZN6000, were selected to make some trial cutting. On the basis of the material compositions, the basic process condition was built, and some cutting experiments were carried out to get the preliminary process parameter combination by use of NA2400.Secondly, refer to the above process parameters, the orthogonal experiments were designed for the first cutting, and the test targets were machining speed, kerf width, surface roughness and the process quality of the rich cobalt interface layer, the test factors were WT,△IP, IP, VG, WS, SA, SB, LQ, OFF and other process parameters. By the analysis of the single factor experiment, the influence of various parameters on the test target was studied. Meanwhile through the optimization of multi-objective experiments, the best combination of process parameters was chosen.Thirdly, to play WEDM performance thoroughly and improve the machining quality, multiple processing tests were performed and evaluated. The results show:(1) a better surface quality of cutting section can be obtained after multiple processing by LS-WEDM. To CTB010, CTH025, BNX20and BZN6000, the surface roughness are RaO.57μm, Ra0.85μm, Ra0.96μm and Ra3.51μm in turn;(2) after five times cutting, to CTH025and CTB010, the depths of the grooves of cobalt-rich interface layer are16.3μm and5.7μm respectively, and the step height is7.4μm for BNX20,11.0μm for BZN6000;(3) the size of the defects in the edge of PCD compact is matched with the size of diamond particle, and BNX20can get better edge quality while BZN6000can get poor edge quality. The minimum grinding margin of PCD cutting tools can be controlled in5-15μm after LS-WEDM, and within10μm for BNX20, but BZN6000needs a larger grinding workload. Finally, visualization technique was used to research on the WEDM, the visualization platform was built preliminarily and some visualization experiments were taken.