考慮跨單元工件及交期績效之群組排程

Abstract

為改善生產環境提高生產效率，以應付市場競爭壓力與人力資源不足 等問題，單元製造系統(Cellular Manufacturing System)觀念的引入為 工業界帶來一個嶄新的方向。其原理是將龐大的生產系統分割成數個製造 單元，以降低各單元的複雜度，達到簡化生產系統的目標。通常單元化( Cellularization)實施的結果，不可避免的會有跨單元工件的產生，這些 工件的出現使得原本簡化的系統再度複雜化，因此須審慎處理，以降低其 對系統的干擾。過去有許多學者提出處理跨單元工件的方法，但當現實環 境無法配合時，我們不得不正視跨單元工件存在的問題。因此，如何將跨 單元工件適當的安排在單元製造系統中，使得單元製造系統能有效的運作 ，便成為一項重要的研究課題。本研究即針對單元製造系統，探討含有跨 單元工件的單元製造系統的排程問題，在考量交期績效條件下，以極小化 平均工件延遲及工件延遲百分比為目標，以八種排程組合尋求工件進入各 單元內之最佳加工順序。模擬結果以EDD/DDFAM,SI/DDFAM的績效表現優於 其它排程組合。 In order to cope with the fast changing market demand , to raised production efficiency , and to amintain the competitive advantage, the concept of cellular manufacturing( CM) becomes one of the most important industerial applications and research directions . The basic idea of CM is a subdivide a large manufacturing system into several small manufacturing cells through the practice of group technology(GT) concept. no matter how sophisticated cell formation technique is employed in the cellularization process, there inevitably exist inter-cell parts which may again complicate the simplified system. The proper management of these inter-cell parts to reduce potential system disturbances is necessary. In the past two decades , several approaches such as alternative design, alternative process plan, duplicate machine, or subcontracting , to eliminate inter-cell parts have been proposed by many well known researchers . However, when the above methods cannot be applied due to economical or technological infeasibility , the inter-cell parts need to be well scheduled in the cellular manufacturing system. Tn fact, shared machines and inter-cell parts exit in most real-world cellular manufacturing system.[Pullen 1976, Wemmerolv and Hyer 1989] Most traditional GT scheduling models assume simplified CM environment without inter-cell parts considered . This research proposes a two phase GT scheduling method by taking inter-cell parts into consideration. This method determine the ultimate job sequence under objectives of minimation of 'average tardiness' and 'percentage of job tardy', respectively. Among eight combinations of dispatching rules, EDD/DDFAM and SI/DDFAM out performed others in most cases.