Ergonomic evaluation: 3-D simulation of cellular versus functional manufacturing systems

The purpose of this research was to investigate for ergonomic advantages of one manufacturing system over another. Lean Manufacturing and the functional manufacturing system design were the competing systems. This investigation was conducted with the aid of high-level 3-D computer graphics simulation and other engineering analytical tools.; An actual manufacturing cell was used to construct computer simulation models of a manufacturing cell and functional workstations. This operating cell was modeled and the results compared favorably with the actual cell's performance history; thus validating the simulation. The functional manufacturing system simulation included identical modeled human workers and utilized the same high level 3-D simulation package as used for the initial cell design. The software simulated and monitored ergonomic functions, in particular, energy expenditure, postures, repetitive motion and other processing functions, such as cycle time.; Three ergonomic areas were analyzed. First, was energy expenditure and the results indicated that the functional system workers carrying out the same work used more energy than the same worker in a cell. The second ergonomic area analyzed was postures via RULA. The results from this research indicate that the RULA tool can be used effectively with the aid of high-level simulation programs. RULA analysis indicated the functional manufacturing system, from a posture perceptive, was more harmful to industrial workers. The third ergonomic area analyzed from the simulation study was repetitive motion. This study investigated the ergonomic and physiological differences between cellular and functional manufacturing systems as related to repetitive motion using the 30 Second Rule and worker cycle time as analysis criteria. The results based on the 30 Second Rule and cycle time of the simulated workers showed that the manufacturing cell design was superior to the functional job shop design.; The design of the manufacturing system may inherently reduce or eliminate physiological problems before they can develop. The initial research points to substantially lower risk from work related injuries when using the cellular manufacturing design rather than the functional job shop design.