The impact of ergonomics on the design of hybrid multi-model production lines in lean manufacturing

Lean manufacturing is a production method aiming to reduce costs and increase productivity by eliminating waste. Previous studies investigating the variations in the quality of working life due to the implementation of lean manufacturing have shown both negative and positive effects on workers health and perceptions of workplace safety and job satisfaction. This study investigates the impact of ergonomics on the design of manufacturing processes following the principles of lean production. A mathematical model is introduced to address the design of hybrid multi-model production lines with both manual and automatic workstations. The model includes the ergonomic risk assessment ensuring an acceptable exposure of the workers to the risk of developing musculoskeletal disorders in hand intensive tasks. The OCRA Index and the Strain Index job analysis methods are included. The aim is to analyze the variations in the solutions of the model, due to the different ergonomic risk assessment method adopted.