本研究是製作一組量測治具並使用游標卡尺來測量手機外殼(手機背面機殼) ,將量測到的數據,利用品質管理上評估製程能力非常重要的三個指標,即Ca值、Cp值和Cpk值,Ca代表製程的準確度,Cp代表製程的精密度, Cpk則是綜合製程能力指數,透過以上這些指標,去分析這項製程的實用性。;This study is to create a set of measuring fixture and use the vernier caliper to measure the phone case (cell phone back case), the measured data. Then we use three important indices of evaluation of process capability ,including Ca , Cp and Cpk. Ca represents the accuracy of capability. Cp represents the precision of capability. Cpk is the Process Capability Index. Through these indices, we can analyze the practicality of this process. Find the disadvantages that we can improve.