Abstract
Multi-Sided assembly line balancing problems commonly arise in plants producing large-sized, high-volume products such as automobiles. Unlike traditional assembly lines, multi-sided lines allow several parallel workplaces (sides) at each workstation, enabling operators or robots to perform different tasks simultaneously on the same product. This paper addresses the multi-sided assembly line balancing problem with assignment restrictions. In this problem, certain tasks must be assigned to the same side (e.g., tasks requiring the same tool or fixture to reduce tooling costs), while others cannot be assigned together (e.g., welding and painting tasks). These requirements are referred to as compatible (positive) and incompatible (negative) zoning constraints. A mixed-integer programming model is proposed to obtain optimal solutions by minimizing line length and the number of stations for a given cycle time. Computational experiments are conducted to evaluate the proposed modelling approach, and the results demonstrate its effectiveness and efficiency.