Abstract:  Mold manufacturing is a nonrepeated process, but it is of single order production. For such processes, part processing time uncertainty is the main characteristics. Thus, in mold manufacturing, the operation may enter a chaotic state due to bad scheduling. In order to obtain a reasonable and feasible production schedule under processing time uncertainty, a discrete probability model is developed for a flexible mold manufacturing flow shop.  Then, a scheduling model is presented for minimizing the expectation of makespan. The problem is solved by a hybrid genetic algorithm which integrates simulated annealing algorithm into the crossover and mutation operations. The proposed method is tested by using practical cases and results show that it is effective.  

Key words: processing time uncertainty, flexible flow shop scheduling, genetic and simulated annealing hybrid algorithm