Study On Balance Optimization Between Product Quality And Efficiency Based On The Mental Workload In The Mixed-Model Assembly Line

The increasing complexity leads to higher mental workload in the mixed-modelassembly process, which causes more human errors. Higher mental workload not onlyaffects the mixed-model assembly line in terms of product quality and productivity,but also harms human health. Therefore, it is necessary to study the effect of mentalworkload on the quality and efficiency from the points of operators, in order to findthe optimal mental workload level for operators by developing a quantitative model.In this paper, time pressure model is used to predict mental workload and thefactor of experience is introduced to modify the mental workload model by analyzingthe impact of various factors on mental workload. According to the curve betweenmental workload and work performance, high or low mental workload is not benefitfor performance and the optimal mental workload exists. So on the basis of theassembly complexity, a rolled throughput yield model is developed though the theorybetween defects and the rolled throughput yield in consideration of the effects mentalworkload has on the assembly performance. Then an optimal model of balancing theproduction quality and efficiency in serial configuration is developed to find theoptimal mental workload of every operator by using the reliability theories. Anumerical example is applied to validate the model. The study shows that whendesigning the mixed-model assembly line, taking the mental workload into accountcan balance the rolled throughput yield and efficiency of the assembly line better.Besides that, improving the experience of the operators is able to mitigate the impactof mental workload on the quality and efficiency and ensures high efficiency as wellas the quality of the output.This research can help determine the optimal metal workload for each operator incase excessive high or low mental workload has negative effects on the quality andefficiency as well as protecting the health of operators. The research has importantpractical value on improving operating environment, reducing human errors and evensecurity incidents. In addition, the study lays a theoretical foundation on designing themixed-model assembly line better and studying the human quality deeply.