Cutting Path Design to Minimize Workpiece Displacement at Cutting Point: Milling of Thin-Walled Parts

Abstract

Vibrations of a tool or workpiece during cutting operations shorten tool life and causes unwanted surface roughness. In this report, we propose an algorithm for determining the sequence of material removal, tool orientation, and feed directions, an algorithm minimizes workpiece displacements by considering workpiece stiffness and cutting force. In this research, the cutting path consists of the material removal sequence, tool orientation and feed directions. The material removal sequence changes the workpiece compliancematrix at the cutting points, and the feed directions and tool orientation change the direction of the cutting force. In our algorithm, workpiece displacements are reduced by changing the material removal sequence and applying the cutting force in the direction of higher workpiece stiffness. A numerical example demonstrates how the algorithm obtains appropriate cutting paths to mill a cantilever form. In the numerical example, three optimized cutting paths are compared with an unoptimized cutting path, a path used by an expert and based on the expert’s personal experience, to machine a low-stiffness workpiece. The obtained material removal sequence of the minimax compliance path is almost the same as that of the unoptimized cutting path. Workpiece displacements at the cutting point of three optimized cutting paths are approximately 10% smaller than those of the unoptimized cutting path. The minimum displacement path is the best of these three optimized cutting paths because fluctuations in workpiece displacements at cutting point are the smallest. These optimized cutting paths show the cutting path strategy as a rough cutting path for machining the thin-walled cantilever.