Error compensation in the end milling of pockets: a methodology

Abstract

The milling process causes machining errors due to several factors such as tool deflection, machine tool geometric errors, thermal effects, tool wear, etc. Among these, tool deflection is the most dominant factor causing contour errors. While it is difficult to eliminate the deflection errors, considerable accuracy of the machined contours can be achieved by compensating the tool deflection errors. In the end milling of pockets, the tool deflection varies over the entire machining cycle, which includes straight segments as well as corners. As the tool deflection varies with the cutting forces over the entire machining cycle, it is necessary to estimate the cutting forces and the deflection errors accurately and quickly. In this paper, a compensation methodology has been developed to integrate both the force and deflection models, based on the cutting force model and discrete deflection model developed for the end milling of pockets consisting of straight and corner sections showing accurate and reliable estimations. This paper also presents a computerized methodology for calculating the voluminous deflection error data. Illustration of the user interface is also presented in this paper with the details of the compensation program algorithms and path determination program for end milling of pockets consisting both straight and corner sections.