Enhanced strategy for milling corners

Abstract

Tool path generation based on contour-parallel offset has many practical applications, especially in pocket milling. However, the tool path segments offset from the pocket boundary usually form many corners. In milling operation, these corners with accumulated material will have an adverse effect on milling performance. This paper proposes an improved numerically controlled (NC) tool path pattern for pocket milling. Bow-like tool path segments are appended to a conventional contour-parallel tool path at the corner positions. The cutter loops along the appended tool path so that the corner material is machined progressively in several passes. By adjusting the number of appended tool path loops, cutting resistance can be controlled. The proposed tool path generation for dealing with different corner shapes was implemented as an add-on user function in a computer aided design/manufacture (CAD/CAM) system. Cutting tests confirmed that the proposed tool path pattern is useful for clearing accumulated material at pocket corners while maintaining a higher cutting stability.