一個提供加速壽命測試之參數制定方法: 以印刷電路板焊接錫球之疲勞壽命評估為例

Abstract

加速壽命測試為提升電子產品可靠度之重要技術，但部分測試參數依賴經驗判斷與類似產品資料，加上電子產品之零件種類繁多，誤差來源多元，使測試參數之制定缺乏完整量化方法。本論文旨在提出一個加速壽命測試之參數制定方法，以電路板焊接錫球之疲勞壽命評估為例，考量電路板模型之幾何不確定因素及測試極限，結合蒙地卡羅方法與失效物理學模型，使用商用數學軟體MATLAB 與商用有限元素模擬軟體ANSYS 實現虛擬電路板模型之加速壽命測試模擬，並以此模型進行虛擬實驗，透過虛擬二因子實驗設計方法計算測試參數之影響趨勢，快速提供初步參數制定建議；若模擬預算充足，進一步透過柏拉圖估算方法，以情境制定方法與比較候選參數解之變異程度，選定柏拉圖集合上之最佳解，提供最終參數制定建議。本論文之方法提供進行真實加速壽命測試前之參數制定建議，輔助決策者選用測試參數，確保加速壽命測試能依照實際工程考量做調整。

Parameters in accelerated Life Test(ALT) are often defined by rules of thumb or similar product experiences. With an increase in electronic product complexity, the uncertainties in predicting reliability increases. This study proposes a methodology for ALT parameters setting under uncertainties and applies the fatigue life reliability assessment of solder joints on printed circuit boards(PCBs). The geometry uncertainties and testing limits of PCBs were considered. Monte Carlo simulation with physics of failure(PoF) models is first developed in MATLAB that integrates the finite element simulation software ANSYS, to create a virtual PCBs model implementation for ALT simulation. Two factors design of experiment (DOE) method is then applied to the model for preliminary parameters setting suggestions. A Pareto set with candidates variances is provided for the optimal setting. This study presents ALT parameters setting suggestion before implementing the actual ALT, helping the designer to choose testing parameters and ensures that the parameters are adjusted to the actual engineering consideration.