Scheduling with lot streaming in a two-machine re-entrant flow shop

Abstract

Lot streaming is splitting a job-lot of identical items into several sublots (portions of a lot) that can be moved to the next machines upon completion so that operations on successive machines can be overlapped; hence, the overall performance of a multi-stage manufacturing environment can be improved. In this study, we consider a scheduling problem with lot streaming in a two-machine re-entrant flow shop in which each job-lot is processed first on Machine 1, then goes to Machine 2 for its second operation before it returns to the primary machine (either Machine 1 or Machine 2) for the third operation. For the two cases of the primary machine, both single-job and multi-job cases are studied independently. Optimal and near-optimal solution procedures are developed. Our objective is to minimize the makespan, which is the maximum completion time of the sublots and job lots in the single-job and multi-job cases, respectively. We prove that the single-job problem is optimally solved in polynomial-time regardless of whether the third operation is performed on Machine 1 or Machine 2. The multi-job problem is also optimally solvable in polynomial time when the third operation is performed on Machine 2. However, we prove that the multi-job problem is NP-hard when the third operation is performed on Machine 1. A global lower bound on the makespan and a simple heuristic algorithm are developed. Our computational experiment results reveal that our proposed heuristic algorithm provides optimal or near-optimal solutions in a very short time.

Simulation of Job Sequencing for Stochastic Scheduling with a Genetic Algorithm

“…Table 1 shows the completion time of each job under the Out-Time column. Çetinkaya & Duman, (2021) developed an approach to minimize completion time of the sublots and job lots with a single job and multiple jobs. (2) 4.…”

Mathematical Modelling of Non-Permutation Flow Shop Processes with Lot Streaming in the Smart Manufacturing Era

“…In this treatment, the number of items to be produced by each job is partitioned such that each part is processed independently. Adding the lot streaming condition to flow shop problems has led to improved performances in the production processes (Sarin & Jaiprakash 2007;Cetinkaya & Duman 2021). Lot streaming does not require neither extra layouts nor new technologies (D'Amico et al 2021), but demand more attention at the shop floor, since orders are now divided in several suborders.…”