Abstract
This paper considers a scheduling problem for multi-machine two-stage process for continuous production to minimize the total earliness under a constraint of no tardy lots. Both stages consist of plural machines, and the processing machine for each lot is different in each stage. Each unit of a lot is delivered to the second stage as soon as it is processed in the first stage, and it is processed simultaneously in the second stage. Every lot must be completed before or just on the due time of each lot, and the setup time depends on lot sequence. An optimization algorithm for the scheduling problem based on the branch-and-bound method is developed to effectively determine the optimum solution. The branching operation and lower bound value in the proposed algorithm will enhance the computational efficiency. Furthermore, the effectiveness of algorithm is reported by some simulation results, and the possibility of applying the algorithm to the processes with more than 2 stages is also discussed.
