近年來由於工業技術的精進，市場對於產品品質的要求逐漸提升，因此製造商必須在品質與成本間取得最佳的權衡，雖然製造設備不斷地在進步，在生產過程中還是會隨著時間而逐漸衰退，並造成品質的不穩定，有鑑於此，許多製造商紛紛以維護來遏止類似情形的產生。
本研究考慮一個不完美生產系統，製造商利用維護增強設備的穩定性，而設備之穩定性可透過設備本身的可靠度資料及其產品之不良率判定，當制定設備之維護計畫時，則以雙因素維護模式作為合理的衡量依據，但以往文獻中，卻缺乏同時考量設備可靠度及產品不良率之維護模式之研究，因此本研究利用雙因素的維護模式，結合可靠度及即時監控下之不良率資料做為決策之依據，透過成本最小化方法，制定設備可靠度及產品不良率之門檻值，以規劃出最適維護策略。並在應用分析中，以數據帶入模式中進行數值分析，討論四種不同生產狀況下之最佳解及總成本值，以對模式結果進行探討，結果顯示越不穩定的系統，所耗費之總成本越高，且適於採用較寬鬆的門檻值，以避免過度頻繁的維護，而後由於現今生產系統多屬於穩定型系統，因此在敏感度分析部分將針對穩定系統狀態進行討論，找出對決策變數影響較大的參數，以供決策者做參考，而由於許多重要參數對於決策結果的影響甚大，因此必須仰賴經驗豐富的專業人員制訂各個參數，得以使此模式發揮最大的效用。本研究藉由整合設備可靠度與產品不良率，並在成本與品質間找到一個最佳的平衡點，藉此作為制定維護計畫之依據，以更貼近實際情形，以提供製造商進行維護制定相關的決策。

Complex systems deteriorate due to age and other external factors during the production process. Maintenance is thus essential, since it can stabilize the system operations and enhance its reliability and availability. The performance of a production system can be measured by its system reliability and product defect rate. Research on finding optimal maintenance policies for deteriorating systems usually consider only single factor. In this study, a two-dimensional maintenance policy is considered in which the reliability can be monitored and the product defect rate can be detected by statistical process control systems, and the total cost function is minimized to determine the optimal thresholds for maintenance actions. A nonhomogeneous Poisson Process with a power law failure intensity function is used to describe the behavior of the deteriorating system. Finally, a numerical example was used to demonstrate the usefulness of the proposed model by balancing the system reliability and product defect rate for an optimal maintenance plan. The proposed model can assist the decision maker in determining the moments of undertaking the maintenance actions.

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