An exact tool allocation approach for CNC machines

An exact approach is developed to determine the optimum machining conditions and tool allocation decisions simultaneously to minimize the total production cost on a CNC turning machine. There are multiple machining operations and we consider a set of alternative cutting tool types for each operation. The existing tool management approaches at the system level fail to relate the tooling issues to the machining conditions, and ignore the tool availability and tool wear restrictions. Consequently, we not only improve the overall solution by exploiting the interactions between these two decision making problems, but also prevent any unfeasibility that might occur for the tool allocation problem due to tool contention among the operations for a limited number of tool types by considering the machining operation, tool availability and tool life limitations. The computational results indicated that the ave rage computation time to find an optimum solution was 1.11 s, whereas the maximum time was 11.45 s, for a set of randomly generated problems.