在生產系統中，製程常會發生異常狀況，管理者為了確保品質穩定，會透過各種品質改善策略來達到穩定製程品質的目的。因為不同品質改善策略，所須付出的品質成本與獲利關係非常複雜，故本研究在統計製程管制架構下，針對製程發生異常狀況，探討管理者採取不同品質改善策略所需付出的成本及預期獲利情況，以品質成本與效益之觀點，考慮產品可維修的情況下，建構品質與成本之利潤增額模型，找出使增額利潤最大化下之最佳品質改善策略。最後舉－數值範例，以驗證此模型之可行性，所獲得之具體結果，可作為後續研究及實務應用之參考。

This paper focuses on the quality improvement strategies for manufacturing processes. When the manufacturing process goes askew, managers apply various quality improvement strategies to maintain product quality. Different strategies have different and complex relationships with quality costs and revenue. In this paper, we propose an incremental profit model to investigate the best quality improvement strategy. Considering that the products can be repaired, we assume that the characteristics of the products are normally distributed with a known mean and variance, and assume a reasonable improvement in the cost and profit structure to obtain the optimal process mean and variance. We then develop a numerical example to illustrate the significance of this research through the results, which can be used in future research and practical applications.