多项质量特性产品的制程能力分析(doc 15页)

多项质量特性产品的制程能力分析(doc 15页)

多項品質特性產品之製程能力分析

Integrated Process Capability Analysis Base On

Multi-characteristic Products

彭文理Wen-Lee Pearn

國立交通大學工業工程與管理學系教授

Professor ,Department of Industrial Engineering

&Management

National Chiao Tung University

Hsinchu, Taiwan, Republic of China

陳坤盛*Kuen-Suan Chen

國立勤益技術學院工業工程與管理系教授

Professor, Department of industrial Engineering & Management

National Chin-yi Institute of Technology

Taichung, Taiwan, Republic of China

( Received April 26 , 2000；First Revised March 2 , 2001；Accepted May 28 , 2001 )

摘要：製程能力指標(Process Capability Index)是一種方便又好用的製程品質評估工具。它提供企業製造商在產品的生產過程中用來評估各項品質特性的製程水準，以提昇品質績效，並滿足客戶的需求。但是最常為工業界採用的C p及C p k指標，在使用上其精確度受到許多的限制，所以[Boyles, 1994]定義了一個與製程良率有一對一數學關係的新指標S p k。然而上述各指標卻都只適合用來評估於單一品質特性的產品。所以對於生產多樣產品及種類的企業而言，無法將之廣泛的應用於多項品質特性產品之製程能力分析與評估，因而無法即時瞭解最終產品與其各品質特性間相關的生產管制資訊。

本文將以S p k指標與製程良率的基礎針對多項品質特性產品之製造環境，探討如何將最終產品所要求的製程良率轉換成各單一品質特性之個別製程所需的生產水準。在本文中我們以[Boyles, 1994]所提出的S p k指標的等高線圖為基礎，參考[Vänn man, 1999]的方法將各個不同製程規格的製程偏移及製程變異程度予以標準化，而將數個不同品質特性的製程指標值描繪於多重製程能力分析圖上並在圖上建立製程能力區塊，作為產品等級分類的依據。依此生產管制人員可從各製程之S p k 指標值落在製程能力分析圖上的位置，迅速的得知各品質特性的製程良率、品質特性偏移目標值的程度(準確度)及其品質特性變異程度(精確度)。所以此一製程能力分析圖可以適用於多項品質特性產品製程的製造環境，且可迅速提供各項品質特性的製程能力與水準，以作為多品質特性製程管制及改善之參考依據。

關鍵詞：製程良率、標準化、多品質特性、製程能力區塊

ABSTRACT :Process Capability index (PCI) is commonly used to evaluate product quality in manufacturing industry. PCI measures quality levels of product characteristic to enhance quality performance and satisfy customers. In practice, the application of PCI is limited in some degree. [Boyles, (1994)] defined an index S pk with one-by-one relationship to process yield. But the above indices could only measure single quality characteristic, and cannot apply to most of the companies producing products with multi-characteristic. Hence. the production information between final products and quality characteristic cannot be controlled immediately.

The approach of the paper is to discuss how to transform the process yield of final product to individual production levels of multi-characteristic based on S pk and process yield. According to the contour plot associated with S pk proposed by [Boyles, (1994)] and [Vännman’s, 1997] method regarding the standardization to process shift and variation of multiple process specifications, we plot process indices of multi-characteristic on one chart and distinguish process capability zone. That is, people responsible for production control can quickly realize the process yield, precision and variation of all quality characteristic by reading the positions where S pk indices locate on the plot. Therefore, the