Due to non-repetitive manufacturing of mould & die industry, the processing time of operations is random uncertainty. Hence, it is difficult to make a reasonable and feasible baseline schedule in the mould shop floor. To deal with this problem, a proactive scheduling algorithm with uncertain processing times was proposed herein. Firstly, how did two critical operations in the mould finishing stage to impact the stability of whole manufacturing system was analyzed. Based on the characteristics of uncertainty of processing time quota, a discrete probability model of processing time uncertainty was developed. Secondly, a proactive scheduling model of two-stage flow shop was built, whose objective was schedule stability. Furthermore, a width-variable beam search(VBS) algorithm was presented for solving the proactive scheduling model. Finally, the comparative analysis with the fixed width beam search(FBS) was pursued. And, the computational results show that the presented algorithm has a good balance between solution quality and computation time.
