Abstract
This study presents a novel method for estimating the surface integrity in end-milling. The mechanical properties of the machined surfaces in cutting affect the quality of the final product. In particular, hardness and residual stress often require strict control, but nondestructive inspection is not easy. This study proposes a method to estimate the hardness and residual stress of end-milled surfaces by analyzing the cutting forces measured on the machine and the tool image. The measured cutting force is analyzed to estimate the specific cutting forces and edge force coefficients. The flank wear width is measured using an on-machine measuring device installed in the machine tool. From this information, the average stresses at the primary and tertiary cutting zones are estimated. The cutting temperature in the primary cutting zone is roughly estimated by considering the shear angle theory. These state quantities are highly correlated with the dislocation density and its change on the machined surface. Therefore, hardness and residual stress are estimated based on a simple linear regression model. Parameter identification was performed based on measured hardness and residual stress in end milling experiments. The experimental results validated that the proposed method can accurately estimate hardness and residual stress.
