INVESTIGATION OF FORCES, POWER AND SURFACE ROUGHNESS IN HARD TURNING WITH MIXED CERAMIC TOOL

Hard turning has been explored as an alternative to cylindrical grinding used in manufacturing parts made of tool steels. In the present study, the effects of cutting speed, feed rate and Depth of Cut (DOC) on cutting force, specific cutting force, power and surface roughness in the hard turning were experimentally investigated. Experiments were carried out using mixed ceramic (Al₂O₃ + TiC) cutting tool having nose radius of 0.8mm, in turning operations on AISI D3 tool steel, heat treated to a hardness of 62 HRC. Response Surface Methodology (RSM) based Central Composite Design (CCD) in Design of Experiments (DOE), was adopted in deciding the number of experiments (20) to be performed with various combinations of input parameters. The range of each one of the three parameters was set at three different levels; namely low, medium and high. The validity of the model was checked by Analysis of Variance (ANOVA). The results yielded that most favorable parameter setting for superior surface finish was acquired at a medium speed of cutting (155 m/min), medium feed (0.075 mm/rev) and low DOC (0.3mm).