Simulation-based assembly line balancing in U-shaped, parallel U-shaped, and parallel adjacent U-shaped layouts

Abstract

This study focuses on layout designs and optimization of assembly line balancing using simulation. Three layouts namely U-shaped lines, parallel U-shaped lines (PUL), and parallel adjacent U-shaped lines (PAUL) are studied and observed by comparing the performances of the layouts in terms of the total number of workstations, line efficiency, and workload smoothness. Besides, selected KPIs are collected to investigate the effects and tradeoffs among the layouts. To achieve the objectives of the study, this research uses secondary data from an industrial case and designs the conceptual models of the three layouts employing ARENA simulation. When each line of the layouts produces a single model, PAUL outperforms all the objectives and resource utilization. Even though it obtains higher average waiting time, PAUL's productivity, WIP, and number in queue are indifferent significantly. When each line produces a mixed model, results do not give any strong contributions, yet it offers another point of consideration. It is noticeable that assigning tasks into workstations play a crucial role in defining the performances of each layout. PAUL is a promising layout for improvement and implementation.