GB/T 40681.5-2021Statistical methods in monitoring process capability and performance - Part 5: Process capability estimates and performance for attributive characteristics (English PDF)

Foreword

The plan of GB/T 40681 "Statistical Methods for Monitoring Production Process Capability and Performance" is divided into the following 8 parts.

---Part 1.General principles and concepts;

---Part 2.Process capability and performance of time-dependent process models;

---Part 3.Research on machine performance of discrete product measurement data;

---Part 4.Process capability estimation and performance measurement;

---Part 5.Process capability and performance estimation of counting characteristics;

---Part 6.Multivariate normal process capability analysis;

---Part 7.Measurement process capability;

---Part 8.Equipment performance analysis of multi-state production process.

This part is Part 5 of GB/T 40681.

This section was drafted in accordance with the rules given in GB/T 1.1-2009.

This part uses the redrafting method to modify and adopt ISO 22514-5.2019 "Statistical Method Capability and Performance in Process Management No. 5

Part. Process Capability and Performance Estimation of Counting Characteristics.

Compared with ISO 22514-5.2019, this part has the following structural adjustments.

--- Divide Chapter 4 into 4.1 symbols and 4.2 abbreviations.

The technical differences between this part and ISO 22514-5.2019 and the reasons are as follows.

---Regarding normative reference documents, this section has made adjustments with technical differences. The adjustments are specifically reflected in Chapter 2 "Regulations"

The specific adjustments are as follows.

* Replace ISO 3534-2 with GB/T 3358.2, which is equivalent to the international standard (see Chapter 3);

---In Chapter 4, the symbol "np" is added and defined as "the average number of unqualified products in the subgroup", which is more accurate;

---The definition of the symbol "p" in Chapter 4 is revised to "overall nonconforming product rate", which is more accurate;

--- In Chapter 4, the symbol "u" is modified to be defined as "the number of unqualified products per unit", which is more accurate;

--- The definition of count data in 5.1 is revised to "indicating whether each individual in the subgroup examined by the record has a certain characteristic (or characteristic)

Levy), calculate the number of individuals with this characteristic, or record the occurrence of such an event in a unit product, a group of products, or a certain area.

The observed value obtained by the number of births, that is, the number of units with a certain attribute or the frequency of occurrence of the characteristic", is more accurate;

---Change "based on one of the four different control charts" in 5.1 to "the number of unqualified items can be monitored using chart c, and the unit product is not compatible

The number of grids can be monitored by u chart, the number of nonconforming products can be monitored by np chart, and the rate of nonconforming products can be monitored by p chart", change

For clearer description;

--- Modify the "use c and u diagrams for the number of nonconforming products, use np and p diagrams for the number of nonconforming products" in 5.3 to "use the number of nonconformances

In figure c, use u figure for the number of unqualified products per unit, use np figure for the number of unqualified products, and use p figure for the rate of unqualified products", change to clear

Clear description;

--- Modify the vertical axis data of Figure 2 and modify the original text error;

--- Change the "p*p, p" in 7.1

pkL

And p*pkU" changed to "p

p, p

pk, p

pkL

And p*pkU", increase p

pk is more accurate;

---The formula (8) "QP-1.96

QP(1-p)

n <= QP < QP 1.96

QP(1-p)

"To

"QP-1.96

QP(1-QP)

m <=QP<=QP 1.96

QP(1-QP)

", modify the original symbol error;

--- Change "z1-p=2.438" in 7.2 to "2.176<=z1-QP< infinity", modify the original calculation and symbol errors;

---In 7.2 "

2.438

3 <=P

pk<=

3->0.81<=P

pk< infinity" is changed to "

2.176

3 <=P

pk<=

3->0.725<=P

pk< infinity ", modify

The calculation and notation of the original text are wrong;

---In Chapter 8, "C*pk, C

pkU

And C*pkL" to "C

p, C

pk, C

pkL

, C*pkU", increase C

pk is more accurate;

---The formula (15) in Chapter 8 "C*pk=

z1-pM

"Amended to "C*pk=

z1-pM

";

--- Change "where z1-p is the quantile of the standard normal distribution of pM" in Chapter 8 to "where z1-pM is the standard normal distribution

pM quantile", modify the original text symbol error.

This section has made the following editorial changes.

---Revised the standard name to "Statistical Methods for Production Process Capability and Performance Monitoring Part 5.Process Capability and Performance of Counting Characteristics"

Can estimate";

--- Modified the description of the scope of application of this section;

--- Amend "ISO 7870-2" in the title of Figure 1 to "GB/T 17989.2";

---Added in 5.3 "Note. The cumulative graph of the number of unqualified products per 100 units means that as the number of subgroups increases, based on all samples currently collected

The number of unqualified products per hundred units in this calculation";

--- Change the "average number of unqualified products per hundred units" in the "Explanation" of Figure 2 to "the number of unqualified products per hundred units based on all samples"

Number of cells";

--- Change the "Lower Confidence Limit" in the "Explanation" of Figure 3 to "Upper Confidence Limit";

--- Change the "Confidence Interval Curve" in the "Explanation" of Figure 3 to "Confidence Upper Limit Curve";

--- Change "PCI confidence interval can be obtained using formula (10)" in 7.2 to "PCI confidence interval can be obtained using formula (8)";

---Added table number and table title;

---Revised references.

This part is proposed and managed by the National Standardization Technical Committee for the Application of Statistical Methods (SAC/TC21).

Drafting organizations of this section. Qingdao University, Inner Mongolia Mengniu Dairy (Group) Co., Ltd., China National Institute of Standardization, Shanxi Huhua Group

Group Co., Ltd., Huzhou Rongke Building Material Technology Co., Ltd., Huzhou Mingfeng Enterprise Management Consulting Co., Ltd., Zhongtong Bus Holding Co., Ltd.

Co., Ltd., Liaocheng Zhuoqun Auto Parts Co., Ltd., Hangzhou Kuangxin Technology Co., Ltd.

Introduction

The methods described in this section are intended to assist agencies or organizations in evaluating the capabilities and performance of their main processes based on counting characteristics.

It is necessary for an organization or institution to use process capability and performance to evaluate the capability and performance of a supplier's production process.

The developed process capability and process performance index contribute to this work.

Statistical methods for production process capability and performance monitoring

Part 5.Process capability and counting characteristics

Performance estimation

1 Scope

This part of GB/T 40681 gives the calculation method of the process capability and performance index of the counting characteristic in the common production process.

This section applies to the process capability and performance evaluation of counting characteristics in common production processes.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article

Pieces. For undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 3358.2 Statistics Vocabulary and Symbols Part 2.Applied Statistics (GB/T 3358.2-2009, ISO 3534-2.2006,

IDT)

3 Terms and definitions

The terms and definitions defined in GB/T 3358.2 apply to this document.

4 Symbols and abbreviations