產品製程能力評估模式

Abstract

製程能力指標可以合理反應製程能力並監控及改進產品品質。本文首先回顧既有的單邊製程能力指標與雙邊製程能力指標（包括對稱與非對稱），並且介紹現有評估多製程產品製程能力、評估多型號望大型產品族製程能力與評估望小型產品族製程能力的方法。 本研究主要包括兩部分：(1) 提出一個多製程產品的評估模式以評估一個同時具有望大、望小與望目的多製程產品的整體製程能力，(2) 提出一個多型號望目型產品族的評估模式以評估一個具有多種型號的望目型產品族的整體製程能力。 本文的第一部份提出一個多製程產品的整體指標以評估一個同時具有望大、望小與望目的多製程產品的整體製程能力，並且說明良率與多製程產品整體指標的關係，藉由產品能力分析圖(Product capability analysis chart)評估各個製程的製程能力是否達到要求，並且提供品質改進的方向。 本文的第二部份提出一個多型號望目型產品族的整體指標以評估一個具有多種型號的望目型產品族的整體製程能力，藉由多型號製程能力分析圖(Multi-model process capability analysis chart)評估各個型號的製程能力是否達到要求，並且提供品質改進的方向。 整體而言，本文破除製程能力指標只能評估單一品質特性的限制，將之發展成可評估一個具有多品質特性的產品與望目產品族的能力指標。

Process capability indices (PCIs) can sum up in numbers what the manufacturing process capabilities reveals and have been used to monitor and improve product qualities meeting specifications. First, the existing process capability indices including unilateral, symmetric bilateral, and asymmetric bilateral are reviewed. Additionally, this work describes the existing methodologies assessing process capability for a multi-process product, and addresses the existed methodologies evaluating the integrated process capability for a product family with larger-the-better or larger-the-better specifications. This study includes two parts: (1) study on how to evaluate the integrated process capability of an entire product together with larger-the-better, smaller-the-better, and nominal-the-best specifications, (2) study on how to assess the integrated process capability of a product family with nominal-the-best specifications. The first part of the study aims to propose an integrated process capability index to precisely measure the integrated process capability for a multi-process product. A product capability analysis chart [PCAC] is introduced for practical application. The second part of the study proposes an integrated process capability index to evaluate a product family with nominal-the-best specifications. And the multi-model process capability analysis charts are introduced to compare the process capabilities of family members both for 100% inspections and sampling plans. As a whole, this study is to break the limitations of process capability indices on treat of a product with multi-process characteristics and a product family with nominal-the-best specifications.