Comparison of Five Alternative Manufacturing Strategies For increasing Job Shop Capacity and Their Impact on Manufacturing Performance

Abstract

Managing job shop manufacturing is quite different compared to other manufacturing systems due to its dynamic changes in process routings, cycle times and fluctuations in demand. Managers in job shops face problems in attaining optimum performance of the job shops. These can lead to failure to meet due dates, low machine level utilization and high level of work-in-progress (WIP). These problems can be exacerbated when management has to consider reacting to increased demand, which requires adding additional capacity. Increasing capacity may involve multiple alternatives for which little practical guidelines currently exist. This research investigates, by using simulation approach, the implication of adopting five possible alternatives of increasing job shop capacity and flexibility in terms of their system performance subjected to varying levels of incoming orders and order priorities. The measures of system performance are i.) minimization of tardy jobs, ii.) level of WIP and iii.) machine utilization. A case study of a mold and die machine shop was used as the basis of the research. It was found that the most optimum alternative in increasing capacity is by selectively introducing machines to duplicate existing ones as opposed to replacing existing ones by a single flexible machine capable of performing operations previously done by several machines. The result of the study also serves as a practical guideline to the managers wishing to add capacity in similar circumstances. This however must be taken within the limitations and constraints of the case study.