Investigation of the effects of machining parameters on the thrust force and cutting torque in the drilling of AISI D2 and AISI D3 cold work tool steels

In this study, the effects of workpiece hardness, drill diameter, drill length and drilling parameters on thrust force and cutting torque are investigated in the drilling of AISI D2 and AISI D3 cold work tool steels under dry drilling conditions. The experiments are performed at three cutting speeds (5, 10 and 15 in/rnin) and three feed rates (0.04, 0.05 and 0.06 mm/rev). Workpiece hardness, drill diameter, drill length, cutting speed are considered as independent variables (machining parameters), and full factorial design is selected for experimental trials. Analysis of variance (ANOVA) is employed to determine the most significant, machining parameters on the thrust force and cutting torque. The predictive equations are developed in confidence intervals with the linear regression analysis to obtain the thrust force and cutting torque as a function of machining parameters and the correlation coefficients (R-2) of equations for thrust force and cutting torque are calculated as 92.7% and 84.1%, respectively. As a result of this study, it is found that all of the machining parameters are effective on the thrust force and cutting torque. Thrust force and cutting torque increase with the increase of workpiece material hardness, drill diameter, drill length, feed rate and number of holes, and decrease with the increase of cutting speed.