ISO 18414-2006 按属性验收取样规程.基于控制出厂质量信用原则的验收零取样系统

标准号：ISO 18414-2006
中文标准名称：按属性验收取样规程.基于控制出厂质量信用原则的验收零取样系统
英文标准名称：Acceptance sampling procedures by attributes - Accept-zero sampling system based on credit principle for controlling outgoing quality
标准类型：A41
发布日期：1999/12/31 12:00:00
实施日期：1999/12/31 12:00:00
中国标准分类号：A41
国际标准分类号：03.120.30
适用范围：1.1 This International Standard specifies a system of single sampling schemes for lot-by-lot inspection byattributes. All the sampling plans of the present system are of accept-zero form, i.e. no lot is accepted if thesample from it contains one or more nonconforming items. The schemes depend on a suitably-definedaverage outgoing quality limit (AOQL), the value of which is chosen by the user; no restrictions are placed onthe choice of the value of the AOQL or on the sizes of successive lots in the series. The methodology ensuresthat the overall average quality reaching the customer or market-place will not exceed the AOQL in the longrun.1.2 The schemes are intended to induce a supplier, through the economic and psychological pressure of lotnon-acceptance and consequent loss of accumulated credit, to attempt to maintain a nonconformity-freeprocess, while assuring, by means of the lowest practicable sample sizes, that the long-term percentage ofnonconforming items delivered to the customer or market-place does not exceed the AOQL. This objective isachieved by a progressive reduction in the sample size in response to good quality history.1.3 The schemes are designed to be applied to a series of lots from each supplier. The credit principleprovides:a) automatic protection to the customer if a deterioration in quality is detected, by means of a total loss ofaccumulated credit and reversion to a relatively large sample size whenever a nonconforming item isfound, and 100 % inspection of1) the first lot if it is not accepted, or2) any non-accepted lot that immediately follows a non-accepted lot;b) an incentive to reduce sampling costs (by means of a progressive reduction in required sample size) ifconsistently good quality is achieved.1.4 This International Standard is designed for use under the following conditions:a) where the inspection procedure is to be applied to a series of lots of discrete items that are intended to beidentical, and which are all supplied by one producer using one production process (If there are differentproducers or production processes, this International Standard is intended to be applied to each oneseparately.);b) where one or more quality characteristics of these products are taken into consideration, which must allbe classifiable as either conforming or nonconforming;c) where the inspection error involved in classifying the state of a product's quality characteristic(s) isnegligible;d) where inspection is non-destructive.This International Standard can be suitable for regulatory purposes, as control of the expected quality of itemsreaching the market-place is achieved with the smallest possible sample sizes, and long-term control of therealized, or actual quality level in the market-place is achieved with certainty, regardless of how long or shortindividual suppliers' series may be. This International Standard can be used by suppliers/producers,buyers/consumers and regulatory agencies to provide control of the expected quality of the totality of acceptedproduct of each type from each source.