Balancing mixed-model assembly lines to reduce work overload

Abstract

We propose a new line balancing approach for mixed-model assembly lines with an emphasis on how the assignment of tasks to stations affects the ability to construct daily sequences of jobs (customer orders) that provide stable workloads (in a minute-to-minute sense) on the assembly line, while also achieving reasonable workload balance among the stations. The issue of short-term workload stability has received little attention in the assembly line balancing literature. Such stability allows assembly workers to complete their tasks without being rushed and thereby contributes to product quality. We propose a new objective for assembly line balancing that helps to achieve better short-term workload stability and develop a heuristic solution procedure based on filtered beam search for this new objective. Computational results show that for small problems (which can be solved optimally), this approach provides near optimal solutions, and for larger problems, it provides significantly better results than traditional assembly line balancing methods.