Selecting an Optimal Tool Sequence for 2.5D Pocket Machining while Considering Tool Holder Collisions

Milling using a sequence of tools has become very attractive with the advent of rapid tool change mechanisms in modern CNC machines. However, the commercial CAM systems used to generate G&M code rely on experienced process planners to select a good tool sequence. When a tool sequence is selected and tool paths are generated, NC-verify systems are used to check the tool paths for tool holder collisions. If tool holder collisions are detected, the part has to be re-planned ab-initio. In this paper, we describe a method to select an optimal tool sequence by formulating the problem under certain assumptions as the shortest path solution to a single source directed acyclic graph. Also described is a method to incorporate tool holder solution in the context of selecting an optimal tool sequence. Examples have been worked out to illustrate the workings of the algorithm. Received: February 2005 / Accepted: September 2005