Virtual and Physical Methods for Efficient Ergonomics Risk Assessments - A Development Process for Application in Car Manufacturing

Licentiate thesis, 2007

Work-related disorders and sick leave are well-known common problems in the manufacturing industry. Workrelated disorders cost both society and the manufacturing industry huge amounts of money every year as a consequence of poor working environment and assembly-unfriendly products. As a result the productivity and product quality in the companies are affected which negatively influence the potential profits. There is a significant correlation between ergonomics, quality and productivity which has been shown in many studies. Good production ergonomic conditions have the potential to decrease work-related sick leave, staff turn-over and increase the product quality and the company profits. Purpose The purpose with the following papers was to find efficient methods for ergonomics evaluations both during manufacturing engineering and during the manufacturing process itself. There are big gains in identifying ergonomic risk factors and in preventing work-related musculoskeletal disorders as early as possible during the development process. Ergonomics mapping and evaluation of entire production systems require deep ergonomics competence and very good knowledge about the local circumstances. Since continuous mapping and risk assessment was a very time consuming business, it was necessary to find better assessment tools and methods. Another troublesome problem was the difficulty to keep the mapping continuously up to date. Thus there was an urgent need to develop more efficient methods for identification, evaluation and classification of ergonomics risks both on product level and on station level in the plants. On plant level a production technician method called ErgoSAM was chosen for study and evaluation. In order to investigate if early proactive identification of potential ergonomic problems during the manufacturing engineering phase of a new product was possible, a new Sport Utility vehicle (SUV) was chosen as an object to study. The purpose was to compare the results of early ergonomics simulations in virtual reality with the results of ergonomics assessments made on physical cars in a traditional manner. The intention was to see what criteria formed the basis for doing ergonomics simulations, to what extent it was possible to perform realistic simulations during early project phases, and to show optional ways of further developing methods and simulation tools. Finally the ambition was to point at good examples of holistic thinking in ergonomics. Result With addition of important data missing and adjustment of assessment parameters in line with company standards for ergonomics, ErgoSAM proved to be a useful and efficient tool for simultaneous time measurements (SAM) and assessment of ergonomics (ERGO). But it is urgent to emphasize that training in ergonomics and in usage of the tool itself is of vital importance for proper application of the data built into ErgoSAM and for adequate outcome of results. The virtual participative working methods proved to work well in general and the members of the module teams (project teams) were very positive to the usage of virtual tools. A big amount of ergonomic problems was paid attention to and solved but the number of ergonomic simulations was lower than expected. The reason for this was referred to as due to lack of ergonomics competence. Nevertheless, the opinion in the module teams was that there was a greater potential to identify and solve several ergonomic problems in early project phases than was the case in this study. An overall important outcome was the recommendations to the company of how to improve virtual working procedures, follow-up of simulation results and improvement of virtual tools for the future. The Corporate Ergonomics Programme at Volvo Car Corporation appeared to be a good example of a macro ergonomic (holistic) approach. The programme resulted in an increased level of knowledge and awareness of the importance of ergonomics beside improved collaboration between stakeholders. Comprehensive technical standards in ergonomics were attained. Documents, checklists and other tools for assessment were developed. Improved cross-functional cooperation within project groups and ergonomic groups was obtained. Absenteeism decreased. Personnel costs went down.