Maintenance Planning in Re-entrant Flow Shop (3rd Report)

—Development of Dispatching Method & Trial Validation—

Abstract

This research paper introduces a development of production management method for equipment maintenance scheduling and work-in-process (WIP) dispatching or scheduling in re-entrant flow manufacturing systems. The method utilizes and combines two published technologies: discrete event-driven simulation and critical ratio dispatching rule. The research established a method of what-if analysis based on actual WIP configuration. Impact of equipment maintenance on system performance is quantified by the simulation. Then, modified critical ratio parameters is applied to maximize bottleneck equipment utilization. The established method, Dynamic Critical Ratio (DCR), has been implemented to a semiconductor manufacturing system. The implementation has avoided WIP blocking in equipment maintenance and WIP starvation at a bottleneck equipment downstream. As a results, the improvement of bottleneck utilization and total system throughput was observed. In closing, possibility for applying the developed method to other production management activities such as equipment re-configuration for product mix and demand change, work shift management and supply chain planning is discussed.