A case study is presented evaluating the productivity and ergonomic consequences of strategies implemented in a re-design of an electronics assembly system. The company applied partial automation strategies for assembly and transportation functions, moving from a parallel-batch to a serial line-based production system. Through simultaneous consideration of technical and ergonomic indicators we aimed to identify linkages between design decisions, productivity, and ergonomics. Data obtained from company records and key company informants were combined with detailed video analysis, biomechanical modelling and field observations of the system. Implementation of the strategy to partly automate assembly operations was seen to reduce labour inputs for component assembly work without directly affecting ergonomic conditions. The automation of transportation strategy reduced both labour inputs and work in progress. This strategy also resulted in considerable reductions in work-task variability, and hence increases in repetitiveness for operators at manual assembly workstations. The manual assembly station examined had some increase in shoulder load amplitudes and a larger increase in the time-density of work (reduced porosity). Work activities were focused almost exclusively on stereotyped ‘get and put’ actions which increased in average frequency from one every 8.3 seconds to one every 7.4 seconds. Workstation design was constrained by initial decisions to adopt automation technologies and also affected by later problems in the automation of assembly. Ergonomic conditions varied across individuals and stations in the system. The adopted work organisation plan resulted in uneven distribution of risk factors across operators in the production system. It is concluded that strategic decisions made early in the design of the production system have considerable impact on ergonomic conditions in the production system. Optimal design for sustainable and efficient production require simultaneous and integrated consideration of technological and operator functions in the manufacturing system.
Neumann, W.P., Kihlberg, S., Medbo, P., Winkel, J. (2001) Integrate Ergonomics into Production System Design. 16th International Conference on Production Research, Prague, CZ. p 39