An Alternate Machining Method for Hardened Automotive Gears

This paper describes an experimental investigation on hard turning of disc type automotive gears made of 20Mn5Cr5 steel hardened to 60±2 HRC against grinding process. Experiments are conducted by using PCBN tools on a CNC turning centre without using coolant. The effect of machining parameters; cutting speed (vc), feed rate (f) and depth of cut (ap) on the surface roughness Ra (µm) is analyzed and optimized with the help of Taguchi design of experiment (DOE), signal to noise (S/N) ratio and analysis of variance (ANOVA) methods. The surface quality, process characteristics, some economical and ecological features of the hard turning are analyzed and compared with the grinding.