Machine dedication and process flexibility in a group technology environment

Abstract

Abstract This study investigates changes in inventory and customer service performance of a job‐shop that desires to adopt a Group Technology (GT) philosophy in its shop floor operations. Simulation methodology is pursued to explore tradeoffs in shop performance between the routing flexibility of non‐dedicated machines in a functional job‐shop and the setup efficiency of dedicated machines in shops that have machine cell layouts. Further, traditional and GT‐based scheduling procedures are investigated in these different shops to determine the conditions under which a GT philosophy may be profitably employed only in layout decisions, only in scheduling decisions, or in both layout and scheduling decisions. Results from this study show that shop layout choice is not a simple decision that can capitalize either on the high routing flexibility of the functional job‐shop or on the setup efficiency advantages of a cell shop. The tradeoffs between routing flexibility and setup efficiency must be made carefully. The impact of demand variability on performance is also dependent on the type of layout. In general, product volume variability more adversely affects the performance of functional job‐shops, while product mix variability has greater impact on the performance of cell shops. Finally, sensitivity analysis is performed to show that maintaining balance between the utilization of machines is a major determinant of performance, and consequently the best layout.