考核产品质量按百分比抽样的弊端

质量监督部门与生产企业对产品进行质量监督把关与验收时,一个非常重要的手段是对产品进行抽样检验,通过检验达到控制产品质量的目的.因此,如何抽样、抽多少样品成了质量控制的关键所在,不管是质量监督部门还是生产企业均不能采用百分比抽样.百分比抽样检验方法既不科学,又达不到质量控制的目的,同时会造成对批量大的检查过严,而对批量小的检查过松的现象.     

浅谈批量外协件的质量控制

所谓批量外协件，是指具有一定批量、由本企业委托其他企业加工制造的零部件。外协件的质量控制，一般依赖于外协件生产厂，委托者往往只是在外协件进厂时进行检验把关。由于这种外协件具有一定的批量，从检验成本。检验周期等方面考虑，通常只能采用抽样检验的方法来判断其质量合格与否。即便对其中一些较重要的项目，也往往只采取增加样本量（即抽检数量）或提高合格质量水平等手段来进行检测控制，而很少采取全数检验的方法。这种质量控制方式，尽管能起到一定的作用，但由于未对整个生产过程进行控制，因而存在着一些缺陷，例如：无法改…     

产品抽样中应注意的问题

产品抽样中应注意的问题秦德忠巩华产品质量检验第一道工序就是从批量产品中按预定的方案抽取样本。经过对样本进行检验，分析计算出样本的质量指标。通过样本的质量情况，推断批量产品总体的质量水平。因此，抽取样本的科学性，在很大程度决定了产品质量检验结果的代表性...     

统计技市在质量管理中的应用(4)

第三节计数调整型连续批抽样检验 GB/T2828.1-2003<计数抽样检验程序第一部分:按接收质量限(AQL)检索的逐批计数抽样计划>就是计数连续批抽样检验计划.     

如何建立产品配件的抽样检验系统

对于在成品中起重要作用又形成一定批量的产品配件，进行100％的检验是不现实的，因此，通过合理有效的抽样检验来确保配件质量，是一项关系成品质量和安全的重要工作。     

抽样工作的探讨

抽样是质量检验部门进行产品质量监督检验前必需的过程,这项工作完成的好坏,即抽检样品是否具有代表性,抽样单填写是否完整、准确,直接影响到质量技术监督行政部门后处理的权威性,因此,抽样是做好监督检验的一项极其重要的工作。一、正确选择抽样检验方案监督检验的产品如果批量大、结构复杂、受检项目多,只能随机抽取一部分产品（样本）进行检验。根据样本检验结果的数据,对该批产品作出合格或不合格的判定,即以部分判定全体,因此,不可避免的存在抽样误差。为了将误差控制在最小范围,在抽样前一定要正确选择抽样方案,并上报主…     

统计技术在质量管理中的应用（4）

GB／T2828．1—2003《计数抽样检验程序第一部分：按接收质量限(AQL)检索的逐批计数抽样计划》就是计数连续批抽样检验计划。它属于计数调整型抽样标准，与国际标准ISO 2859-1：1999相对应，主要适用于连续批的检验；当认真考虑抽样方案的抽查特性曲线时，也可以用于孤立批的检验。     

谈抽样与检验工作

抽样及检验工作在质量技术监督工作中具有十分重要的地位和作用。抽样工作是检验工作的前提和基础,只有抽样人员将样品抽来,检验人员才能依据标准进行检验,出具检验数据。而检验工作则是抽样工作的结果和保证,二者缺一不可、相辅相成。一、抽样工作是质检工作首要的、关键的环节。抽样工作的好与坏直接影响到质检机构的权威性和公正性,但由于种种原因,抽样工作不尽如人意,存在着以下几个问题：１－抽样的方式多是依据上级下达的每个季度的任务进行定期抽检。定期抽检有其利也有其弊,利是有计划、有组织、好管理、易检验、有批量。然…     

连续批检验中采用固定抽样方案之我见

在连续批的抽样检验中,确定取样多少（即样本量n）是一个非常重要的工作。对于通常的随机抽样检验,应首先定性的分析样本量确定的影响因素,然后才可以用精度和费用等量化的因子进行定量的分析。基于此基础,相应的就产生了固定样本量的抽样检验方案,因为该方案既保证了抽样检验的风险,同时又很好地结合考虑了量化因子的影响。     

关于企业产品标准中检验规则编写若干问题的探讨（下）

3．关于周期检验抽样方案（GB／T2829）的正确应用 企业产品标准中涉及周期性检验时,往往采用抽样检验国家标准GB／T2829—2002《周期检验计数抽样程序及表（适用于对过程稳定性的检验）》。该标准也足基于统计抽样的检验方法。对于其适用范围,应把握这几点：     

Estimators for particulate sampling derived from a multinomial distribution

Counting the number of units is not always practical during the sampling of particulate materials: it is often much easier to sample a fixed volume or fixed mass of particles. Hence, a class of sampling designs is proposed which leads to samples that have approximately a constant mass or a constant volume. For these sampling designs, estimators were derived which are a ratio of arbitrary sample totals. A Taylor expansion was used to obtain a first-order approximation for the expected value and variance in the limit of a large batch-to-sample size ratio. Furthermore, a π -estimator for a ratio of batch totals was found by deriving expressions for the first- and second-order inclusion probabilities. Practical application of the π -estimator is limited because it requires inaccessible batch information. However, when the denominator of the estimated batch ratio is the batch size, the π -estimator becomes equal to a sample total divided by the sample size in the limit of a large sample-to-particle size ratio. As a consequence, the obtained sample ratio becomes an unbiased estimator for the corresponding batch ratio. Retaining unbiasedness, the Horvitz–Thompson estimator for the variance, which also contains inaccessible batch information, is replaced by an estimator containing sample information only. Practical application of this estimator is illustrated for the sampling of slag, produced during the production of steel.     

De omvang van de steekproef bij een enkelvoudig steekproefsysteem

Summary  (Sample size for a single sampling scheme).
The operating characteristic of a sampling scheme may be specified by the producers 1 in 20 risk point ( p ₁), at which the probability of rejecting a batch is 0.05, and the consumers 1 in 20 risk point ( p ₂) at which the probability of accepting a batch of that quality is also 0.05.
A nomogram is given (fig. 2) to determine for single sampling schemes and for given values of p₁ and p ₂ the necessary sample size ( n ) and the allowable number of defectives in the sample ( c ).
The nomogram may reversedly be used to determine the producers and consumers 1 in 20 risk points for a given single sampling scheme.
The curves in this nomogram were computed from a table of percentage points of the χ² distribution. For v > 30 Wilson and Hilferty's approximation to the χ² distribution was used.     

基于嵌入式系统的便携式多参数监护仪具体实施

针对监护仪的原理和功能进行详细分析,介绍了监护仪应达到的各项标准,找到与产品接近的嵌入式产品,在此基础上,确定相应的工作程序,实现监护仪从生产样机到小批量生产切实可行的方法。     

Revisiting the theory of production competence: Extensions and cross-validations

This paper examines a widely cited work in operations management, the theory of production competence, advanced initially by Cleveland, Schroeder, and Anderson (CSA). This intuitively appealing proposition asserts that production competence leads to improved business performance. However, CSA's empirical work has been criticized by Vickery and her collaborators and by Safizadeh, Ritzman, and Mallick (SRM). Moreover, SRM's own empirical work suggested that the CSA proposition only holds for batch processes. Using data from two large studies, we avoid the problems that plagued CSA's analysis, improve on their result, and call into question the SRM finding that restricts that result to batch operations.     

Confidence intervals for batch properties based on both sampling and analytical variance

Summary If different random samples are taken from a heterogeneous batch and each sample is analysed once or in replicate, the average result is a point estimation of the true but unknown mean of the batch property concerned. In this paper, formulae are given for the numbers of degrees of freedom, which are necessary for interval estimations based on both the sampling and the analytical variance. It is essential to distinguish between situations in which estimates of the variances are available and in which they are not.     

白车身质量关键控制点的设立和控制方法

随着汽车行业的迅猛发展，批量生产的制造模式，生产节拍越来越快，用户对汽车的制造质量以及安全性能也更为关注，如何在生产过程中保证关键环节的质量要求，避免出现批量质量问题变得越来越重要。文章通过介绍白车身焊点结构特点，对白车身关键点的设立原则及控制方法进行研究，从根本上保证白车身的关键过程制造质量。     

A Destructive Sampling Method Designed for Outsourcing Situations Involving High Quality Production Processes

In outsourcing situations involving manufacturing and assembly, the sampling of units produced is important since in many situations not all of the units can be tested. Destructive sampling, which commonly occurs in the assembly and manufacturing industry, is a form of sampling where all units produced cannot be tested since the parts are destructively tested. In this situation, sampling techniques are used to determine if an entire lot should be accepted or rejected based on the sampling results. The traditional sampling techniques include single or classical sampling, double sampling, multiple sampling, skip-lot sampling, chain sampling and MIL-STD-105E. The purpose of this paper is to develop a sophisticated technique that monitors quality at a lower cost than traditional methods yet has similar monitoring characteristics in situations where quality is high and tests are destructive. The proposed technique, Destructive Sampling Method for High Quality production processes (DSM-HQ), is based on a cost function, which balances the costs of sampling versus the costs of finding a defect on the field. DSM-HQ assumes to have a Poisson process defect pattern and uses an Empirical Bayesian analysis to allow the researcher to include prior knowledge.     

论成本管理会计技术在政府的应用

成本会计技术是汇总、计算、分析和解释各种成本的方法,一般包括分批法和分步法、标准成本法和作业成本法等。在新公共管理背景下,政府更加强调成本和绩效,为政府借鉴企业成本会计技术提供了必要和可能,但由于政府的非营利性,应对其进行适当的调整。     

白车身质量关键控制点的设立和控制方法

随着汽车行业的迅猛发展,批量生产的制造模式,生产节拍越来越快,用户对汽车的制造质量以及安全性能也更为关注,如何在生产过程中保证关键环节的质量要求,避免出现批量质量问题变得越来越重要。文章通过介绍白车身焊点结构特点,对白车身关键点的设立原则及控制方法进行研究,从根本上保证白车身的关键过程制造质量。