基於製程績效指標之計量型快速轉換抽樣系統

Variables Quick Switching Sampling System Based on Process Performance Index

施美旭(Shih, Mei Hsu)

指導教授 ： 吳建瑋

國立清華大學/工學院/工業工程與工程管理學系/碩士(2015年)

摘要

隨著產品日新月異，產品的週期也越來越短，學者利用數理統計的概念發展驗收抽樣計畫（Acceptance Sampling Plans）來提高檢驗效率，其被廣泛運用在品質管理及品質保證領域中，可提供生產者與消費者判定貨批品質水準是否滿足要求之決策準則。隨著科技的發達，生產技術與品質不斷的提升，不良率使用百萬分之一（Parts Per Million, PPM）來計算，計數型驗收抽樣計畫將不再適用，近年來許多學者將製程能力指標（Process Capability Indices, PCIs）應用在驗收抽樣計畫上，不僅擁有計量型驗收抽樣計畫的主要優點，有效解決傳統計數型驗收抽樣計畫，且透過精確的抽樣分配，可提供較佳的準確度和可信度。
因此，本研究的目的為發展一基於製程能力指標Cpk之計量型快速轉換抽樣（Variables Quick Switching Sampling System, VQSS System）系統。VQSS System乃是利用正常檢驗（Normal inspection）與加嚴檢驗（Tightened inspection）兩種不同檢驗水準之單次抽樣計畫所結合的一套系統。開始從正常檢驗開始，精神為在品質轉差時，正常檢驗下會拒絕貨批，且下次轉為加嚴檢驗，而當品質轉好時接受送驗貨批，下次檢驗轉回正常檢驗，利用這樣快速轉換的機制，將可有效地兼顧買賣雙方保障及節省抽樣成本。
VQSS System在正常及加嚴檢驗下利用抽取不同樣本數(nN、nT)以及不同臨界值(kN、kT)去判斷是否允收，而本研究將探討三種不同參數組合型態之VQSS System，透過多種品質水準與風險要求組合，利用非線性規劃求解，並彙整三種型態下之VQSS System計畫參數值，以供未來在不同使用時機下應用，利用操作特性曲線及抽樣樣本數進行分析、亦與單次驗收抽樣計畫比較及探討。最後以實例作為分析與說明，進而呈現本研究之貢獻。

關鍵字

驗收抽樣計畫 ； 快速轉換系統 ； 製程能力指標

並列摘要

Acceptance sampling plans are practical tools for quality management applications and provide the producer and consumer a general rule for lot sentencing and reduce the cost. As the rapid advancement of manufacturing technology, suppliers required their products to be of high quality with very low fraction of defectives often measured in Parts Per Million（PPM）. Process capability indices are convenient and powerful tools for measuring process performance and it is widely used in Acceptance sampling plans.
This paper attempts to develop a Variables Quick Switching Sampling System（VQSS System）based on the Cpk index. The VQSS System consists of two inspection plan along with a set of switching rules between them. The first sampling plan, called normal inspection plan, is applied for periods with good quality. The second sampling plan, called tightened inspection plan, is applied for use during problems encountered periods.
The probabilities of acceptance under normal inspection and tightened inspection are derived, and the proposed VQSS System is also developed based on the exact sampling distribution rather than approximation approach. Three types of the proposed plan parameters are determined by solving a non-linear optimization problem with two-point conditions on the OC curve. The behavior and performance of the proposed sampling system is discussed and also compared with the conventional variables sampling plans. Finally, tables of the plan parameters for various selected quality levels and risks are provided for practical applications.

並列關鍵字

Acceptance Sampling Plan ； Quick Switching Sampling System ； Process Capability Index

參考文獻

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