Ergonomics in car disassembly industry on the edge of major rationalizations

Sammanfattning: A new EU directive on used vehicles has recently been introduced. It demands that for every scrapped car, at least 85% by weight must be recycled by the year 2006 and 95% by 2015. Today this level is about 80%. The growing car disassembly industry was chosen as the study object of this thesis. Due to the increased demands on recycling, the disassembly industry is expected to undergo comprehensive rationalizations and expand into a modern mass-type production. Thus, this thesis investigates the current status of the car disassembly industry with special focus on production systems and ergonomics issues in this context. Paper 1 incorporated the initial efforts, which aimed to explore the current status of the car disassembly industry. The purpose was to obtain knowledge about ergonomics and production systems, as well as to obtain knowledge about ideas, plans and views on the future situation of the industry and production systems. Qualitative methods were utilized. Dismantlers, manufacturers and authority stakeholders described current production systems as ‘craft-type’, i.e. containing a rich variety of tasks as well as considerable periods of set-up time. The dismantling companies faced modest competition and reported good profitability. Future expectations about production systems were that the amount of non-profit work per car would increase. Due to the new legislative demands, disassembly of more parts and materials than today is expected. Today these materials lack market value. For production to stay profitable in spite of increased time in non-value-adding tasks, comprehensive rationalizations are anticipated. Paper 2 was a follow-up study to further investigate the hypotheses generated in Paper 1 with quantitative assessments of mechanical exposures in disassembly. New parameters were utilized for documenting changes in exposures due to rationalizations. Disassembly work was divided into four task groups. These were: direct work (value-adding tasks), and material/tool handling, casual tasks and unplanned breaks (all three non-value-adding). The study shows that disassembly implied high circulatory loads, more walking and higher lumbar peak loads as compared to assembly work. Value-adding tasks comprised only 30% of the total working time, and implied more awkward postures and higher velocities for the head, arm, upper back and wrist than non-value-adding tasks, as well as less time in rest. It is concluded that the ‘craft-type’ disassembly work of today offers a considerable potential for rationalizations. Rationalizations are expected to increase ergonomic exposures. This gives a reason to act proactively in the prevention of musculoskeletal disorders. Due to the legislation, the time span until the year 2015 gives an opportunity to work proactively to obtain future sustainable production systems for car disassembly.