Prediction and analysis impact of operational design of a manual assembly system with walking workers on performance

Abstract

Manual assembly lines, with workers travelling with the work along the line to perform all required tasks, are an example of assembly systems which have greater flexibility over traditional systems due to an improved response to product demand variability. Implementing assembly systems in this way is difficult, especially when operational design reflects an incomplete understanding of how workers can best perform within the system. Different operational designs for such systems have a profound impact on the performance of the system in terms of productivity and ergonomics. This paper analyses the performance of walking worker assembly line (WWAL) in different operational designs. A mathematical model was developed, which considers the effects of a number of operational design variables. An industrial case study is presented here to demonstrate the effectiveness of the proposed model. The results indicate that WWAL can be designed to improve performance, flexibility and labour costs by approaching productivity and ergonomics collaboratively. The results obtained by the model prediction were compared with computer simulation results. Comparison validated the accuracy of the proposed model. The model provides partial characterisations of the optimal design of WWAL and can be used to develop heuristics for local or global optimisation.