產品或元件會隨著使用時間增加或環境影響產生自然退化逐漸喪失其應有功能變為失效的狀態，在現今市場對產品可靠度有著高度的要求，廠商在開發新產品初期或變更產品設計階段，能否充分了解其品質之可靠度，是一項重要的課題。 本研究以個案公司之水量計盒體為研究對象，使用80°C和90°C兩種溫度條件進行加速壽命試驗，探討盒體在熱應力下之可靠度變化，試驗以完全失效資料型態蒐集失效資料，接著擬合失效資料機率分配，以最適當之機率分配模型估計相關參數，運用阿氏壽命模式得出其活化能及加速因子，估算產品在正常使用條件下之產品壽命。

The product or component will gradually loses its proper function and becomes invalid as the use time increases or effect by natural deterioration occurs by environmental impact. In the current market, there is a high demand for product reliability, and it is important issue to know product’s reliability for the manufacturer in the early stages. In this study, use the case of the water meter by an individual case company as the research object. Using 80°C and 90°C temperature conditions for accelerated life test to explore the reliability change of the case under thermal stress with complete failure data. After fitted probability distribution of failure data, use the relevant distribution model to estimated parameters, and activation energy and acceleration factor are calculated by Arrhenius model, and then estimate product’s lifetime under normal conditions.