An Accurate Method for Determining Cutter-Workpiece Engagements in Five-Axis Milling With a General Tool Considering Cutter Runout

Abstract

Cutter runout is universal and inevitable in milling process and has a direct impact on the shape of the in-process geometry. However, most of the works on the cutter-workpiece engagement (CWE) extraction neglect the cutter runout impact, which will result in a loss of precision. In this paper, an accurate method is presented to obtain CWE boundaries in five-axis milling with a general tool integrating the cutter runout impact. First, each flute's rotary surface is analytically derived. Then, by intersecting the section circle corresponding to the current flute with each of the rotary surface formed by previous flutes, a set of candidate feasible contact arcs (CFCAs) are obtained, and the valid feasible contact arc (VFCA) is defined as the common intersection of these CFCAs. Next, by intersecting the VFCA with the workpiece surfaces, the partial arc which locates inside the workpiece volume is extracted as the engagement arc. Finally, the CWE map is plotted by mapping a set of engagement arcs to a 2D space. To validate the proposed method, the CWE maps with/without integrating the cutter runout impact in five-axis milling of an axial compressor blisk are extracted and compared. The results reveal that the shape of CWE boundaries is changed a lot owing to the cutter runout impact. A cutting force comparison experiment has been carried out to show that the proposed method will lead to higher prediction accuracy especially in the finish milling process with low immersion angle.