Fuzzy multi-objective model for assembly line balancing with ergonomic risks consideration

The main motivation behind the improvement of manufacturing systems is that they are competing for a larger share and better image in the market. Many manufacturing systems, particularly those with repetitive products, utilize assembly lines for the final stage of their production systems. Most of the assembly lines still rely on human worker performance since higher flexibility can be attained with manual systems. The performance of manual assembly line systems depends on how ergonomic factors are involved with balancing the lines. Therefore, the main focus of this study is to develop a model to design assembly lines with ergonomic risk consideration. Ergonomic risks are the factors of weight, size, and shape of the components in addition to the posture of the workers performing the tasks with the components. This study also conducts ergonomic risk analysis for assembly tasks using simulation software and incorporates the results into the developed model. There are two conflicting objectives in the problem, thus the required solution model is constructed as multi-objective. Since the objectives of the problem have vagueness, the proposed model is developed adopting fuzzy set theory. The developed fuzzy multi-objective model is implemented in a real-life case problem gathered from a refrigerator company.