Quality Control Fundamentals质量控制基本原理Quality质量Quality has become one of the most important consumer decision factors in the selection among competing products and services. The phenomenon is widespread, regardless of whether the consumer is an individual, an industrial organization, a retail store, a bank or financial institution, or a military defense program. Consequently, understanding and improving quality are key factors leading to business success, growth, and enhanced competitiveness. There is a substantial return on investment from improved quality and from successfully employing quality as an integral part of overall business strategy.质量是消费者在激烈的产品和服务竞争中进行选择的一个重要因素.不管这个消费者是个人、产业组织、零售店或防务工程,这个想象是普遍存在的.因此,关注并提升质量是取得成功、发展并强化竞争力的关键因素.投资质量的提升并把质量作为经营策略的主要部分将会得到极大地回报.We may define quality in many ways. Most people have a conceptual understanding of quality as relating to one or more desirable characteristics that a product or service should possess. Although this conceptual understanding is certainly a useful starting point, we will give a more precise and useful definition.我们对质量有很多种定义.许多人在观念上把质量理解为产品或服务拥有一个或更多满意的性能.尽管这种概念性理解是有效地,我们将给出更精确、有效地定义.Quality---- characteristic or property consisting of several well-defined technical and aesthetic, hence subjective, considerations; conformance to design (customer) requirement.质量-特性或性能中包含几种明确定义的技术的美学的,因此主观考虑；满足设计（顾客）需求.Quality control------detecting poor quality (nonconformance) in manufactured products and taking corrective action to eliminate i t.质量控制-检测在工业产品中检测不合格的质量（不合格品）并采取纠正措施去避免.The traditional definition of quality is based on the viewpoint that products and services must meet the requirement of those who use them. Therefore, Quality means fitness for use.传统的质量定义是产品或服务必须满足使用者的需求.因此,质量就是适用度There are two general aspects of fitness for use: quality of design and quality of conformance.适用度一般有两个方面:设计质量和一致性的质量。
Quality by design intent refers to the various grades or levels of quality that are intentionally determined by design. All goods and services are produced in variousgrades or levels of quality. These variations in grades or levels of quality are intentional, and, consequently, the appropriate technical term is quality of design.设计意图的质量指的是设计中故意设计的各种等级或质量等级。
所有的商品和服务都是在不同的等级或质量等级中产生的。
这些变化的等级或质量水平是故意的，因此，适当的技术术语称之为设计质量。
Quality of conformance refers to how well the product conforms to specifications required by design.产品质量的一致性是指如何符合规范设计的要求。
Quality of conformance is influenced by a number of factors, includingthe choice of manufacturing processes, the training and supervision of the workforce, the types of process controls, tests, and inspection activities thatare employed, the extent to which these procedures are followed, and the motivation of the workforce to achieve quality.一致性质量受到很多因素的影响,包括生产流程的选择、员工的培训和监督，所采用的过程控制,测试,和检查活动的类型,这些程序被遵循的程度 ,激励员工来实现质量。
Unfortunately, this definition has become associated more with the conformance aspect of quality than with design. This is in part due to the lackof formal education most designers and engineers receive in qualityengineering methodology. This also leads to much less focus on the customerand more of a “conformance-to-specifications” approach to quality, regardlessof whether the product, even when produced to standards, was actually“fit-foruse” by the customer. Also, there is still a widespread belief that qualityis a problem that can be dealt with solely in manufacturing, or that the onlyway quality can be improved is by “gold-plating” the product.不幸的是,相对于设计，这个定义更多的关于质量的一致性。
这部分是由于大多数设计师和工程师缺乏质量工程方法的正规教育。
这也导致更少地关注客户和更多关注质量与规格一致,无论产品，即使生产标准，实际上是“适合使用”的客户。
同时,普遍仍认为,在生产制造中质量问题完全可以解决,或者唯一的可以提高质的方式是给产品“镀金”。
We prefer a modern definition of quality:Quality is inverselyproportional to variability. Note that this definition implies that if variability inthe important characteristics of a product decreases, the quality of the product increases. As an example of the operational effectiveness of this definition, afew years ago, one of the automobile companies in the United Statesperformed a comparative study of a transmission that was manufactured in a domestic plant and by a Japanese supplier.我们倾向于质量的现代定义:质量与变化成反比。
请注意,这个定义意味着如果产品的重要特征的变化减少,产品的质量就会提高。
举一个这个定义的操作效益的例子,几年前, 美国的一个汽车公司进行了一个在国内工厂制造过程的传输和由日本供应商制造过程的传输的比较研究。
An analysis of warranty claims and repair costs indicated that there was astriking difference between the two sources of production, with theJapanese-produced transmission having much lower costs, as shown in Fig.5.1. As part of the study to discover the cause of this difference in cost and performance, the company selected random samples of transmissions fromeach plant, disassembled them, and measured several critical quality characteristics.保修索赔和维修费用的分析表明，两者的生产有着显着的区别，如图5.1所示，日本制造的运输成本很低。