在製程中，機器設備的預防維護保養是相當重要的，在機器設備故障前進行維護保養，使機器設備維持一定的可靠度，以利製程順利進行，若機器設備發生故障，將會影響到生產線上的運作和生產排程。本研究利用預定年限更換策略並將預防維護加入(1.在預防保養時，機台狀況良好，只需要做簡單的潤滑、清潔。2.在預防保養時，機台出現異常，但不影響生產作業，需要更換消耗性部件。3.在預防保養時，機台出現異常，接下來可能會造成機台故障，需要更換機台重要的部件。)三種狀態加以討論，結合經濟性設計，建立一套有效預防維護計畫。利用所建立之系統，求算出抽樣間隔、抽樣數量對成本的影響，並求出每台機器單位期望成本並最適預防保養間隔。

In the process, the preventive maintenance of mechanical equipment is very important. Carry out maintenance before the failure of mechanical equipment, so as to maintain certain reliability of the mechanical equipment, so as to facilitate the smooth progress of the process, if the mechanical equipment fails, it will affect Production line operation and production scheduling. This study uses a Replacement at Predetermined Age and adds preventive maintenance (1. During preventive maintenance, the machine is in good condition, only simple lubrication and cleaning are required. 2. During preventive maintenance, the machine is abnormal, but it does not affect production. Operation, the consumable parts need to be replaced. 3. During the preventive maintenance, the machine is abnormal, which may cause the machine to malfunction, and the important parts of the machine need to be replaced.) Three states are discussed, combined with economic design, to establish a An effective preventive maintenance plan. Using the established system, calculate the impact of sampling interval and sampling quantity on cost, and calculate the expected cost of each machine unit and the optimal preventive maintenance interval.