Assembly Line Balancing with buffers by Multiple Criteria optimization

One of the problems in the design of multi-station lines is the allocation of different work elements to various workstations. This problem is called Assembly Line Balancing (ALB). The failure of workstations and other unforeseen circumstances can result in unnecessary idling of the production line. In order to improve the production rate of such systems, buffer storage of certain capacities can be allocated between each pair of workstations. In this paper, ALB with buffers is formulated as a Single Criterion Decision Making as well as a Multiple Criteria Decision Making problem. In the single objective problem, the cycle time is given and the optimal number of workstations and buffer sizes is obtained to minimize the total cost. In the Multiple Criteria problem, several criteria (objectives) are defined. These objectives are the number of workstations, their buffer sizes, the cycle time, and the total cost of operation with buffers. The paper demonstrates how the set of efficient (nondominated) alternatives for the multiple criteria problem can be generated. It also describes how the best alternative can be selected through the use of existing interactive multiple criteria methods. Several examples are solved and the results of computational experiments are provided.