Integrated steepest-directed and iso-cusped toolpath generation for three-axis CNC machining of sculptured parts

Abstract

Today, sculptured parts are widely used in aeronautical, automotive, and many other industries. To make high-quality sculptured surfaces through efficient toolpaths in three-axis CNC machining is a major technical challenge. In this work, a new toolpath generation method for three-axis CNC milling, the Steepest-Directed and Iso-Cusped (SDIC) toolpath generation scheme, is introduced. The method integrates the steepest-directed and iso-cusped toolpaths in three-axis CNC programming. The steepest-directed toolpaths ensure the best geometry matching between cutter and surface for high cutting efficiency, and form a frame to control the trend in direction of the iso-cusped toolpaths. The iso-cusped toolpaths eliminate overmachining on the surface. Their combination ensures high sculptured part productivity, less redundant milling, and good surface quality. Machining examples of a half-cylinder part and a sculptured part are used to illustrate and to compare a range of SDIC toolpath patterns. The proposed SDIC toolpath scheme produces shorter toolpaths with higher machining efficiency. With the help of global optimization algorithms, this method of optimal toolpath generation can be applied to three-axis CNC machining of sculptured surfaces.