DBR系統生產線設計研究

Abstract

本文主要在探討傳統追求產能平衡的生產線設計與限制驅導式排程與管理（Drum-Buffer-Rope, DBR)斜坡保護產能的生產線設計之優劣比較。良好的生產製造系統能夠降低生產週期時間與提高達交率。為了達成這些目標，製造系統必須應付各種變異事件與隨機波動的影響，同時要使生產成本極小化。鑑於此，傳統生產上追求產能平衡並在各製程前面設置大量在製品，來保護整個生產線，此導致較長的生產週期時間，容易傷害交期的可靠度。而由限制理論(Theory of Constraints, TOC)所延伸出來的DBR生產，是藉由初始投料與瓶頸的控制，讓系統的產出與瓶頸同步，達到生產線流量(Flow)平衡，並配合斜坡式的保護產能，來保護整個生產線，此外斜坡產能投資額的大小會因瓶頸的位置而異，一般斜坡產能投資金額會比以傳統追求產能平衡的設計高很多，但是它對於降低在製品，生產週期時間與交期產出產生不錯的效益，至於效益有多大，本研究方法將以一虛擬的生產線，分別以傳統與DBR方式來規劃設計，再以EM-Plant軟體建構模擬系統來模擬實際生產運作的結果。

The purpose of this paper is to compare the benefits of two ways of production line design. One is traditional capacity balance design, and the other is DBR（Drum-Buffer-Rope, DBR）ramp-up protective capacity design. A good manufacturing system is enable to reduce production cycle time and raises the reliability of due day. In order to reach the objectives, manufacturing system must overcome the effects of various variable events, random fluctuation on production line, and minimum of the production cost as well. In view of the foregoing, traditional production system pursues capacity balance and places work-in-process (WIP) inventory in front of every machines to protect overall line, which will lead to production cycle time raise and lower the reliability of due day. Meanwhile, the DBR production system pursues flow balance and ramp-up capacity to protect overall line, ramp-up capacity investment will change by line bottleneck’s location. In general, ramp-up capacity investment will greater than traditional capacity balance, but it will show good results in lowering WIP, cycle time, and due day. As to the results, how many the benefits will be? In order to answer the benefits, this research builds a simulation production line (DBR and traditional system) with EM-Plant software to simulate and analyze the results of both production line design concepts. It shows that the DBR system gets better results than traditional system as a whole.