An efficient cutter contact curve tool path regeneration algorithm for sculptured surface machining

Abstract

Mould design modification is a common process in the mould manufacturing industry. When a mould design is changed, tool paths that cover the modified region must be regenerated. Traditionally, if a mould design is modified, all the generated tool paths must be recalculated, which is very time consuming and error prone. This paper presents a new tool path regeneration algorithm based on the CC (cutter contact) curve tool path generation topology, where a CC curve is the curve on the workpiece surface along which the cutter contacts the workpiece. With this algorithm, the affected cutter location (CL) points are identified efficiently from the tool paths that are generated from the original mould design. Gouge-free CL points are then calculated to replace the affected ones. When the new CL points are calculated, their scallop height values are checked. If they are greater than the given value, new tool path rows are added to maintain the required surface finish. The unaffected CL points will be reused to machine the modified mould directly, and this can reduce the tool path regeneration time and the occurrence of NC programming errors significantly, especially for machining complex sculptured surfaces. The algorithm has been tested on several industrial parts and it was found to be efficient and robust, and the regenerated tool paths are gouge-free and smooth. © IMechE 2004.