Application of tabu search to process plan optimization for four-axis computer-numerically controlled turning centres

This paper describes our adaptation of the tabu search methodology to solve the process plan optimization problem for four-axis CNC turning centres. Optimization of a process plan (specifically, the allocation of operations to spindles and turrets) to minimize the cycle time for machining a workpiece is not a trivial problem. This is due to the highly combinatorial nature of the problem that arises from the presence of dual spindles and dual turrets and the machine's ability to perform operations in parallel machining and simultaneous machining modes. Our experiments to date have shown that the tabu search based approach can be very effective in process plan optimization, and is well suited for incorporation in CAD/CAM systems for four-axis CNC turning centres.