Assembly Line and Workload Balancing with Competency-Based Worker Assignment in Apparel Production

Abstract

The apparel industry is challenging for production management due to rapid changes in fashion. Accordingly customer needs and expectations increase constantly. As a result apparel factories must be able to increase production rate efficiency and quality in order to survive in this dynamic world. To this end assembly line balancing which affects the overall cost and efficiency in apparel industry plays a critical role. In this study real-life assembly line balancing and competency-based worker assignment problems in apparel industry sewing workshop are examined simultaneously and implementation at a big apparel company is presented. A novel mathematical model is proposed to solve this integrated problem. Operation-worker and operation-workstation assignments are made for a given number of workstations operations and workers. The competency score of the worker on each machine type is a key factor in determining worker-operation assignment. Assignments are made in such a way that the total competency score of the line must exceed a pre-specified limit. The objective is to minimize the workload difference between workers on the assembly line for a given cycle time limit. The proposed model is solved using Google OR-Tools and is verified using real-life data from the company. Since the competency of the workers is crucial in operations based on manual labor the proposed model can also be adapted to many industries in addition to the apparel industry. © 2024 Elsevier B.V. All rights reserved.