Owing to heavy dynamic and thermal loads, PCBN tools are seriously worn during hard cutting, which largely constrains the improvement of their machining performance. Therein, the chamfered structure of a cutting edge has a notable influence on the tool wear. Thus, a comparative study was carried out on the wear morphology and wear mechanism of PCBN tools with either a variable chamfered edge or an invariable chamfered edge. The results indicate that, for a PCBN tool with a variable chamfered edge, the rake wear area is far from the cutting edge and slowly extends toward it. A shallow large-area crater wear occurs on the rake face, and the flank wear area has a long triangular shape with a smaller wear area and width, and the cutting edge remains in a good state during the cutting process. In contrast, for a PCBN tool with an invariable chamfered edge, a deep small-area crater appears on the rake face, and the wear area is close to the cutting edge and quickly extends toward it. Thus, it is easy for chips to accumulate in the crater, resulting in large-area and high-speed wear on the flank face. In addition, the tool shows a weak wear resistance. In the initial wear stage, the rake wear mechanism of the two cutting tools is a mixture of abrasive, oxidation, and other types of wear, whereas their flank wear mechanism is dominated by abrasive wear. With an aggravation of the tool wear, the oxidation and diffusion wear mechanism are both increasingly strengthened. The rake wear of the cutter with a variable chamfered edge showed an obvious increase in the oxidation and diffusion wear, as did the flank wear of the cutter with an invariable chamfered edge. This study revealed the wear mechanism of the PCBN tool with a variable chamfered edge and provided theoretical and technological support for its popularization and application in the machining of high-hardness materials.
[1] S Chinchanikar, S K Choudhury. Machining of hardened steel: Experimental investigations, performance modeling and cooling techniques: A review. International Journal of Machine Tools and Manufacture, 2015, 89: 95-109.
[2] G Bartarya, S K Choudhury. State of the art in hard turning. International Journal of Machine Tools and Manufacture, 2012, 52: 1-14.
[3] C S Kumar, S K Patel. Application of surface modification techniques during hard turning: Present work and future prospects. International Journal of Refractory Metals and Hard Material, 2018, 76: 112-127.
[4] M Dogra, V S Sharma, A Sachdeva, et al. Tool wear, chip formation and workpiece surface issues in CBN hard turning: A review. International Journal of Precision Engineering and Manufacturing, 2010, 11(2): 341-358.
[5] S Saini, I S Ahuja, V S Sharma. Residual stresses, surface roughness, and tool wear in hard turning: A comprehensive review. Materials and Manufacturing Processes, 2012, 27(6): 583-598.
[6] O Gutnichenko, V Bushlya, J M Zhou, et al. tool wear and vibrations generated when turning high-chromium white cast iron with pcbn tools. Procedia CIRP, 2016, 46: 285-289.
[7] F Klocke, H Kratz. Advanced tool edge geometry for high precision hard turning. CIRP Annals-Manufacturing Technology, 2005, 54(1): 47-50.
[8] Y K Chou, C J Evans, M M Barash. Experimental investigation on CBN turning of hardened AISI 52100 steel. Journal of Materials Processing Technology, 2002, 124(3): 274-283.
[9] J M Zhou, H Walter, M Andersson, et al. Effect of chamfer angle on wear of PCBN cutting tool. International Journal of Machine Tools and Manufacture, 2003, 43(3): 301-305.
[10] R T Coelho, E G Ng, M A Elbestawi. Tool wear when turning hardened AISI 4340 with coated PCBN tools using finishing cutting conditions. International Journal of Machine Tools and Manufacture, 2007, 47(2): 263-272.
[11] J A Arsecularatne, L C Zhang, C Montross, et al. On machining of hardened AISI D2 steel with PCBN tools. Journal of Materials Processing Technology, 2006, 171(2): 244-252.
[12] G Poulachon, B P Bandyopadhyay, I S Jawahir, et al. The influence of the microstructure of hardened tool steel workpiece on the wear of PCBN cutting tools. International Journal of Machine Tools and Manufacture, 2003, 43(2): 139-144.
[13] T Zhao, J M Zhou, V Bushlya, et al. Effect of cutting edge radius on surface roughness and tool wear in hard turning of AISI 52100 steel. International Journal of Advanced Manufacturing Technology, 2017, 91(9-12): 3611-3618.
[14] S R Das, D Dhupal, A Kumar. Study of surface roughness and flank wear in hard turning of AISI 4140 steel with coated ceramic inserts. Journal of Mechanical Science and Technology, 2015, 29(10): 4329-4340.
[15] N Anmark, T Bjork, A Ganea, et al. The effect of inclusion composition on tool wear in hard part turning using PCBN cutting tool. Wear, 2015, 334-335: 13-22.
[16] K Ramanuj, A K Sahoo, P C Mishra, et al. An investigation to study the wear characteristics and comparative performance of cutting inserts during hard turning. International Journal of Machining and Machinability of Materials, 2018, 20(4): 320-344.
[17] F Mahfoudi, G List, A Molinari, et al. High speed turning for hard material with PCBN inserts: tool wear analysis. International Journal of Machining and Machinability of Materials, 2008, 3(1/2): 62-79.
[18] Y Huang, T G Dawson. Tool crater wear depth modeling in CBN hard turning. Wear, 2005, 258(9): 1455-1461.
[19] T Özel. Computational modelling of 3D turning: Influence of edge micro-geometry on forces, stresses, friction and tool wear in PCBN tooling. Journal of Materials Processing Technology, 2009, 209(11): 5167-5177.
[20] T Özel, Y Karpat, A Srivastava. Hard turning with variable micro-geometry PCBN tools. CIRP Annals-Manufacturing Technology, 2008, 57(1): 73-76.
[21] J Angseryd, H O Andrén. An in-depth investigation of the cutting speed impact on the degraded microstructure of worn PCBN cutting tools. Wear, 2011, 271(9-10): 2610-2618.
[22] K Katuku, A Koursaris, I Sigalas. Wear mechanisms of PCBN cutting tools when dry turning ASTM Grade 2 austetmpered ductile iron under finishing conditions. Wear, 2010, 268(1): 294-301.
[23] E Uhlmann, H Riemer, D Schroter, et al. Investigation of wear resistance of coated PCBN turning tools for hard machining. International Journal of Refractory Metals and Hard Materials, 2018, 72: 270-275.
[24] L H Tang, Y J Sun, B D Li, et al. Wear performance and mechanisms of PCBN tool in dry hard turning of AISI D2 hardened steel. Tribology International, 2019, 132: 228-236.
[25] B Denkena, J Köhler, C VenturaInt. Grinding of PCBN cutting inserts. International Journal of Refractory Metals and Hard Materials, 2014, 42(1): 91-96.
[26] C Ventura, J Köhler, B Denkena. Strategies for grinding of chamfers in cutting inserts. Precision Engineering, 2014, 38: 749-758.
[27] T Chen, D Y Wang, S Y Li, et al. Manufacture and grinding accuracy detection of pcbn tools with variable chamfer edge. Journal of Mechanical Engineering, 2018, 54(11): 214-221. (in Chinese)
[28] B Denkena, J Köhler, B Breidenstein, et al. Influence of the cutting edge preparation method on characteristics and performance of PVD coated carbide inserts in hard turning. Surface and Coatings Technology, 2014, 254: 447-454.
[29] C Venture, J Kohler, B Denkena. Influence of cutting edge geometry on tool wear performance in interrupted hard turning. Journal of Manufacturing Processes, 2015, 19: 129-134.
[30] T Chen, J Guo, S Y Li, et al. Experimental study on high-speed hard cutting by PCBN tools with variable chamfered edge. International Journal of Advanced Manufacturing Technology, 2018, 97(9): 4209-4216.
