Study on Job Shop Scheduling with Many Function-Same Machines

Aiming at some operations of job can be assembled by any machine selected from the function-same machine set, a secondary optimization algorithm for operations on function-same machines is put forward: the machine which can make the completion time of operation early will be selected according to a dispatching rule (earliest due date, EDD), and operations are arranged in the right position of machine selected, then each operation can be assembled as soon as possible, and the total processing time of job can be shortened as soon as possible. To independent operations optimum scheduling algorithm is adopted: the inserting position of operations will be confirmed according to the margin that processing time of operations is subtracted from idle time of machine, and the operation will be inserted in the position with minimal margin. The experiment shows that the new algorithm without increasing complexity has better scheduling result for job shop scheduling problem with many function-same machines.