Mechanical exposures in serial flow assembly - a proactive intervention research approach

The EU End of Life Vehicle (ELV) Directive 2000/53/EC has prompted rationalization initiatives to facilitate recycling of material and components from ELVs. In the present study, technical recordings were used to assess operators' mechanical exposures in a new serial flow system for full material recovery in car disassembly as compared with those of a previous study of traditional craft-type-parallel disassembly. Estimated task-specific mechanical exposures served as a base to simulate how further rationalisation may affect ergonomics in car disassembly. The time proportion of ‘direct work’ (deemed value-adding tasks) was about 30% in both systems, i.e. substantially lower than in modern forward factories. Movement velocities were higher in the new serial system, implying a higher risk for musculoskeletal disorders, while mixed results were found in the comparison of postures.Simulations revealed increased mechanical exposures, illustrated by increased time in high risk conditions, and decreased duration in low-exposure conditions, when indirect tasks and disturbances (deemed non-value-adding) were removed.This may illustrate the underlying mechanism of how rationalisations to eliminate "waste" can reduce valuable recovery time and increase employee injury risk over time.