Heuristic-based approach to solve layout design and workers’ assignment problem in the cellular manufacturing system

Abstract

The design process of a cellular manufacturing system (CMS) involves well-known NP-hard problems. Being an NP-hard, it is difficult to address these CMS-related problems optimally within a reasonable time. Therefore, this paper proposes a novel heuristic-based two-stage approach to tackle the CMS-related problems. In the first stage, a mathematical model is developed to concurrently solve cell formation and workers’ assignment problems (CFWAP). The worker’s selection is determined by their performance in operating a machine for a specific part, measured by the defect rate resulting from assigning the worker to a machine. The model’s objective is to minimize the weighted sum of the total inter-cell, intra-cell movements, operation, and defect costs. In the second stage, based on the output of the mathematical model in the first stage, a heuristic algorithm is developed to solve the problem related to the layout design of the cellular manufacturing system (LDCMS). The actual dimensions of machines and the aisle distances between them are considered in LDCMS to find out the best possible allocation of the machines and cells within the entire system. A comparison is conducted between numerical examples from the literature to show the efficiency and the validation of this two-stage heuristic approach. The results show that the proposed method can optimally tackle the aforementioned CMS-related problems within a reasonable time. To the best of our knowledge, this is the first study that integrates the CFWAP with LDCMS, considering all these practical and manufacturing features. Finally, it should be noted that the proposed approach has been applied as a real case study for a central workshop on die manufacturing for a food stove company in Egypt. The results depict a significant reduction in the company’s total associated costs by achieving up to 23% savings from applying the proposed method.