Influence of cutting parameters on force coefficients and stability in plunge milling

Abstract

Fixed dynamometer is often used to collect cutting force data in plunge milling. The cutting force test signal is distorted because of the dynamic characteristics of the test system consisting of the workpiece and the dynamometer. Then the accuracy of cutting force coefficients based on experimental data analysis is affected. The inverse filtering technique is utilized to compensate for the measurement signal dynamically and verified by experiments. The influence of cutting parameters on cutting force coefficients is investigated by means of the nonlinear instantaneous milling force method. The results demonstrate that the cutting force coefficient has a nonlinear relationship with the feed per tooth and the spindle speed. An improved semi-discrete method is proposed for the machining feature of the plunge milling and utilized to predict the stability of the plunge milling. The measurement signal is analyzed by using the nonlinear method such as phase plane and Poincare section; the accuracy of the prediction of the stability lobe diagram is verified. The results demonstrate that the stability boundary of instantaneous cutting force coefficients is higher than that of the average cutting force coefficients. The research results provide theoretical guidance for the optimization of cutting parameters in the actual machining process.