Determination of force coefficient based on instantaneous forces and linear mechanistic model in ball end milling

Abstract

Due to the intricate geometry, force prediction in the ball end milling process (BMP) is a challenging task. Cutting forces generated during BMP have an impact on important aspects of machining characteristics such as form error, chatter and vibration, surface finish, tool wear, and dimensional accuracy. These machining problems might be resolved by foreknowledge of the cutting forces. In the present research, a new and quick mathematical model based on the linear mechanistic method is reported to determine the force coefficients. The cutter’s hemispherical part is discretized into five discs along the axis at 0.4 mm uniform spacing in the range of 0.2–1.8 mm. For one cutter revolution, forces in the tangential, radial, and axial directions are measured for each disc to prevent radial runout. The current disc makes use of the preceding disc’s cutting force. To derive the shear and edge force coefficients, these are further divided into edge and shear forces. Validation experiments have been conducted and compared with the simulated forces to assess the predictive power of the developed force coefficient model. The predicted results are found to be remarkably close to the experimental results with an error of 5.5%, −8.6%, and 8.9% at 6631 rpm and 2.8%, −4.4%, and 2.21% at 10,052 rpm in tangential, radial, and axial forces, respectively.