A high-efficiency rough milling strategy for mould core machining

Abstract

Increasing the efficiency of rough machining operations can produce significant productivity improvement in mould and die making because most of the metal is removed in the roughing stage. In this paper, a high-efficiency 2.5-dimensional rough milling strategy for mould core machining is presented. The strategy consists of three different tool paths. The first tool path is generated on the basis of the convex hull boundary of a machining region. Owing to the absence of concave tool path segments, the convex hull based tool path can eliminate the chip load fluctuation problem encountered in corner cutting. The second tool path is an enhanced unidirectional straight-line tool path, which has the virtue of maintaining a steady cutting resistance throughout. The large staircases left behind by these two tool paths are refined by using the third tool path which is a contour-parallel tool path that cuts the mould core layer by layer in an upward manner. After applying these three tool paths, the stock material left on the mould core surface can be post-processed by the subsequent finish milling operation. A case study is illustrated to demonstrate the practicality of the presented rough milling strategy.