Protective capacity positioning: Impact on manufacturing cell performance

Protective capacity is the ‘extra’ capacity placed at non-bottleneck resources to absorb random disruptions in planned levels of performance so that the bottleneck resource is more effectively utilized. Although informative, the research related to protective capacity offers little insight into the preferred placement of protective capacity. By building on the existing research, our study develops hypotheses related to protective capacity positioning and then tested them by using a simulation model of a manufacturing cell. The results indicate that the placement of the protective capacity has no practical influence on mean flow time, but it strongly influences bottleneck shiftiness. Specifically, the study's results may indicate that under conditions of high work center utilization, the placement of protective capacity immediately before and after the bottleneck with a high proportion distributed to the upstream work centers may significantly lower bottleneck shiftiness. Several future research needs are discussed.