Designing parallel assembly lines with split workplaces: Model and optimization procedure

A production system which consists of a number of parallel assembly lines is considered. On each line a certain product is manufactured observing a common cycle time. By arranging the lines in a favourable manner, it is possible to increase efficiency of the production system by combining stations of neighbouring lines when balancing them. The objective is to minimize the number of workplaces (operators) required. This problem is called parallel assembly line balancing problem (PALBP) and has previously been considered by Gökçen et al. [2006. Balancing of parallel assembly lines. Int. J. Prod. Econ. 103, 600-609]. In the paper on hand, we give a detailed problem description and model the problem as a binary linear programme. Furthermore, an exact solution approach based on an extension of the well-known branch-and-bound procedure Salome is proposed. Computational experiments show that this procedure clearly outperforms other approaches as it is able to solve small- to medium-sized problem instances to optimality and provides good heuristic solutions for large-sized problems.