ارزیابی ارگونومیک طرح های سیستم تولیدی

Using high-level, 3-D computer graphics simulation and other engineering analysis tools, this research investigates the ergonomic advantages of one manufacturing system design over another. The designs compared are lean manufacturing (manufacturing cells) and the functional (job shop) design. Simulation models based on an actual manufacturing cell and its workers are used to generate corresponding functional workstations with identically modeled workers. Three ergonomic areas—kilocalorie expenditure, potential for harmful postures, and potential for repetitive motion disorders—are analyzed from simulated and monitored data on energy expenditure, postures, repetitive motion, and other processing functions, such as cycle time. Initial research indicates a substantially lower risk from work-related injuries when using the cellular manufacturing design rather than the functional job shop design; thus, the design of the manufacturing system may inherently reduce or eliminate physiological problems before they develop. In addition, 3-D simulation software with ergonomic analysis functions is shown to be an extremely effective tool for the manufacturing system designer and the ergonomist.

This research sought quantitative evidence that the design of a manufacturing system directly affects the physiological and ergonomic functions of workers and shows how manufacturing system design can be developed concurrently with ergonomic and safety considerations. Computer simulation was the primary tool for the three-dimensional simulation and ergonomic analysis of two manufacturing system designs: lean manufacturing (cellular manufacturing) and the functional job shop design. Other industrial and manufacturing engineering analysis tools supplemented the graphical 3-D simulation analysis. Manufacturing systems are considered essential by most nations for the creation of wealth; however, manufacturing systems are complex and require careful and considered planning to maximize profits while minimizing risk. Ergonomics is the science of the relationship between man and work and is loosely defined as “making the job fit the worker.” Computer simulation, in particular, 3-D and virtual reality simulation, is the science of generating digital images of products, processes, and systems to study the relationships between these elements. Often these programs have various analytical tools built in.

This initial research, using high-level 3-D simulation and analysis as a primary tool, has shown in three analyses that the type of manufacturing system design determines to a large extent the probability of potential work-related musculoskeletal disorders. This study modeled and simulated both a cellular manufacturing system and then the same CMS decomposed into functional job shop workstations. The three analyses, which were computer and hybrid-combination manual generated, tested for (1) kilocalorie expenditure, (2) potential for harmful postures via the RULA tool, and (3) repetitive motion disorders of the arm/wrist and upper arm/shoulder utilizing the 30 Second Rule. In all three analyses, the results revealed that the lean production manufacturing cell was superior to the functional job shop concerning the ergonomic and physiological factors analyzed. Further study is being conducted to verify these initial results for different models of various cellular and job shop manufacturing systems; however, based on these first results, it appears that the cellular manufacturing system designer cannot only justify the lean production methodologies based on production increases and inventory reduction but also by decreases in work-related musculoskeletal disorders.