Handling Tool Holder Collision in Optimal Tool Sequence Selection for 2.5-D Pocket Machining

Significant cycle time saving can be achieved in 2.5-D milling by intelligently selecting tool sequences. The problem of finding the optimal tool sequence was formulated as finding the shortest path in a single-source single-sink directed acyclic graph. The nodes in the graph represented the state of the stock after the tool named in the node was done machining and the edges represented the cost of machining. In this paper a novel method for handling tool holder collision in the graph-based algorithm for optimal tool sequence selection has been developed. The method consists of iteratively solving the graph for the shortest path, validating the solution by checking for tool holder collisions and eliminating problematic edges in the graph. Also described is a method to reduce the complexity of building the tool sequence graph in case there are tool holder collisions.