DIN ISO 3951-1-2008 变量检验用取样程序.第1部分:按接收质量限(AQL)检索的单一质量特性和单一AQL的逐批检验一次抽样计划的规范

标准号：DIN ISO 3951-1-2008
中文标准名称：变量检验用取样程序.第1部分:按接收质量限(AQL)检索的单一质量特性和单一AQL的逐批检验一次抽样计划的规范
英文标准名称：Sampling procedures for inspection by variables - Part 1: Specification for single sampling plans indexed by acceptance quality limit (AQL) for lot-by-lot inspection for a single quality characteristic and a single AQL (ISO 3951-1:2005); Text in German an
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
引用标准：ISO 2859-1;ISO 3534-1;ISO 3534-2
适用范围：This part of ISO 3951 specifies an acceptance sampling system of single sampling plans for inspection byvariables, in which the acceptability of a lot is implicitly determined from an estimate of the percentage ofnonconforming items in the process, based on a random sample of items from the lot.This part of ISO 3951 is primarily designed for application under the following conditions:a) where the inspection procedure is to be applied to a continuing series of lots of discrete products all supplied by one producer using one production process;b) where only a single quality characteristic x of these products is taken into consideration, which must be measurable on a continuous scale;c) where the measurement error is negligible, i.e. with a standard deviation no more than 10 % of the process standard deviation;d) where production is stable (under statistical control) and the quality characteristic x is distributed according to a normal distribution or a close approximation to the normal distribution;e) where a contract or standard defines an upper specification limit U, a lower specification limit L, or both; an item is qualified as conforming if and only if its measured quality characteristic x satisfies the appropriate one of the following inequalities: 1) x ≥ L(i.e. the lower specification limit is not violated); 2) x ≤ U (i.e. the upper specification limit is not violated); 3) x ≥ Land x ≤ U (i.e. neither the lower nor the upper specification limit is violated).Inequalities 1) and 2) are called cases with a single specification limit, and 3) a case with double specificationlimits.If double specification limits apply, it is assumed in this part of ISO 3951 that conformance to bothspecification limits is equally important to the integrity of the product; in such cases it is appropriate to apply asingle AQL to the combined percentage of product outside the two specification limits. This is referred to ascombined control.