变量检验抽样程序第6部分:以极限质量（LQ）为指标的独立批次检验单次抽样计划规范

[中文适用范围]： 本文件规定了用于按变量检验的单次抽样方案的验收抽样系统，主要适用于下列情况：a) 检验程序应用于由一个生产商通过一种生产工艺供应的孤立批次的离散产品；b) 仅考虑该工艺的单个质量特性 x，该特性可在连续范围内测量；c) 质量特性 x 服从正态分布或接近正态分布；d) 质量特性的测量没有误差或有中等测量误差；e) 合同或标准定义了规格下限 L、规格上限 U 或两者；当且仅当测得的质量特性 x 满足下列不等式中的相应一个时，产品才被认定为合格：1) x ≥ L（即不违反规格下限）；2) x ≤ U（即不违反规格上限）； 3) x ≥ L 且 x ≤ U（即，既不违反下限也不违反上限）。不等式 1) 和 2) 是具有单个规格限值的情况，而不等式 3) 是具有双重规格限值的情况。当适用双重规格限值时，本文件假定符合两个规格限值对于产品的完整性同样重要。在这种情况下，对两个规格限值之外的产品组合部分应用单个 LQ 是适当的。这称为组合控制。 [外文原描述]： This document specifies an acceptance sampling system of single sampling plans for inspection by variables, primarily designed for use under the following conditions: a) where the inspection procedure is applied to an isolated lot of discrete products all supplied by one producer using one production process; b) where only a single quality characteristic, x , of this process is taken into consideration, which is measurable on a continuous scale; c) where the quality characteristic, x , is distributed according to a normal distribution or a close approximation to a normal distribution; d) where the quality characteristic can be measured without error or with moderate measurement error; e) where a contract or standard defines a lower specification limit, L , an upper specification limit, U , 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 ≥ L and x ≤ U (i.e. neither the lower nor the upper specification limit is violated). Inequalities 1) and 2) are cases with a single specification limit, whereas inequality 3) is a case with double specification limits. Where double specification limits apply, it is assumed in this document that conformance to both specification limits is equally important to the integrity of the product. In such cases, it is appropriate to apply a single LQ to the combined fraction of a product outside the two specification limits. This is referred to as combined control.