Multiple spindle CNC machines

We introduce a unique scheduling and tool assignment problem that arises for multiple spindle machine tools. The capability of these machines to perform simultaneous operations on one or more parts creates constraints that are not found in the traditional scheduling literature. Two solution methodologies using a genetic algorithm with the random keys encoding are introduced for these problems. One is a hybrid genetic algorithm that incorporates a dispatching rule. The effectiveness of these methods is demonstrated on test problems with comparisons to lower bounds.