Performance analysis of a production system with subsidiary facilities required for processing

Abstract

As production automation proceeds to higher degrees, the subsidiary facilities supporting the main facilities (including machines and work stations) during job processing and the part handling devices transferring parts from a machine to another become important factors to be considered more seriously in designing and operating their associated production system. This thesis considers two problems of computing performance measures for systems with subsidiary facilities and another problem of operation scheduling under operation restrictions on subsidiary facilities, where finite number of subsidiary facilities are involved. In thd first problem, a single machine (main facility) with subsidiary facilities is considered, under the assumptions that job interarrival times and service times are exponentially desitributed and that each subsidiary facility assisting the main facility during job processing requires post-processing (such as cleaning, maintenance, etc.) after its own service. In addition, post-processing times are assumed to be exponentially distributed. A computation procedure for system throughput and average system size is developed for both delay and loss cases. In the second problem, a flow shop with subsidiary facilities, where any intermediate buffer between successive machines is not allowed, is considered. In the problem, each subsidiary facility works as a job holder and it is assumed that job interarrival times are exponentially distributed and processing times at each machine are deterministic. A computation procedure for system throughput is developed for both delay and loss cases. Finally, a deterministic environment, different from the two problems, is considered. That is, the flow shop problem with no intermediate queue is considered. The objective of the problem is to determine the optimal sequence of a given set of jobs so as to minimize makespan. Each subsidiary facility also works as a job holder, holding single job at a time. Job rea...