《ASQ-Z1.9-2003.pdf》由会员分享,可在线阅读,更多相关《ASQ-Z1.9-2003.pdf(116页珍藏版)》请在三一文库上搜索。
1、ANSIIASQ Z1.9-2003 AMERICAN NATIONAL STANDARD SAMPLING PROCEDURES AND TABLES FOR INSPECTION BY VARIABLES FOR PERCENT NONCONFORMING AMERICAN SOCIETY FOR QUALITY 600 NORTH PLANKINTON AVENUE MI LWAU KEE, WISCONSIN 5320 1 ANSIIASQ Z1.9-2003 AMERICAN NATIONAL STANDARD SAMPLING PROCEDURES AND TABLES FOR I
2、NSPECTION BY VARIABLES FOR PERCENT NONCONFORMING PREPARED BY ACCREDITED STANDARDS COMMITTEE Zl SUBCOMMITTEE ON STATISTICS SPONSOR AND SECRETARIAT AMERICAN SOCIETY FOR QUALITY ABSTRACT Sampling Procedures and Tables for Inspection by Variables for Percent Nonconfomiing is an acceptance sampling syste
3、m to be used on a continuing stream of lots for AQL specified. It provides tightened, normal, and reduced plans to be used on measurements which are normally distributed. Variation may be measured by sample standard deviation, sample range, or known standard deviation. It is applicable only when the
4、 normality of the measurements is assured. AMERICAN NATIONAL STANDARD: An American National Standard implies a consensus of those substantially con- cerned with its scope and provisions. An American National Standard is intended as a guide to aid the manufacturer, the consumer, and the general publi
5、c. The existence of an American National Standard does not in any respect preclude any- one, whether he has approved the standard or not, from manufacturing, marketing, purchasing, or using products, process- es, or procedures not conforming to the standard. American National Standards are subject t
6、o periodic review and users are cautioned to obtain the latest edition. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken to reaffirm, revise, or withdraw this standard no
7、later than five years from the date of publication. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. 02003 by ASQ Copyright protection notice for the ANSIIASQ 21.9-2003 Standard. This Standard
8、is subject to copyright claims of ANSI, and ASQ. Not for resale. No part of this publication may be reproduced in any form, including an electronic retrieval system, without the prior written permission of ASQ. All requests pertaining to the ANSIIASQ Z1.9-2003 Standard should be submitted to ASQ. AS
9、Q will consider requests for change and information on the submittal of such requests regarding this Standard. All requests should be in writing to the attention of the Standards Administrator at the address below. ASQ Mission: The American Society for Quality advances individual and organizational
10、petformance excellence worldwide by providing opportunities for learning, quality improvement, and knowledge exchange. Published by: Quality Preu 6 N. Plankinton Avenue Milwaukaa, Wisconsin 53203 Call toll fraa 800-248-1 946 Fax 41 4-272-1 734 www.asq.org http:/quahyprers.asq.org http:/stondaFdsgrnu
11、p.oq.org E-mail: authorsasq.org AMLIILLS Lnr,il iilil ciu*l.rt- ANSI/ASQ Z1.9-2003 FOREWORD (This foreword is not a part of Draft American National Standard-Sampling Procedures and Tables for Inspection by Variables for Percent Nonconforming, ANSI/ASQ Z 1.9-2003) This revision of ANSVASQC 21.9-1993,
12、 “Sampling Procedures and Tables for Inspection by Variables for Percent Nonconforming” was undertaken to allow for aligning the terminology of the standard with the terms of ANSI/ISO/ASQ A3534-2-2004 (to be published), change the term Acceptable Quality Level (AQL) to Acceptance Quality Limit (AQL)
13、, change the dehition and explanation of AQL, change the Discontinuation of Inspection Rule, and to correct typographical and computational errors within the standard. The present revision ANSI/ASQ Z 1.9-2003 continues to allow complete interchangeability of the tabulated plans with IS0 3951-1, whic
14、h provided a graphical means for implementation of the plans. ANSI/ASQ 21.9-2003 is also roughly matched to ANSI/ASQ Z1.4-2003, which corresponds directly to the old military standard MIL-STD-105E. The matching is sufficient to allow inspection under either standard for stated AQLs and inspection le
15、vels with reasonably equivalent pro- tection. Tables are given in Section E-Appendix that show differences in protection between ANSI/ASQ Z l .9-2003 and ANSI/ASQ 21.4-2003. These are for use in critical applications to determine whether moving from one standard to the other is appropriate. Committe
16、e members serving as writers and editors of this standard were: Herbert C. Monnich, Jr., Chairperson William C. Davis Rudolf G. Kittlitz, Jr. Paul Roediger Edward G. Schilling . 111 (This page intentionally left blank) ANSIIASQ Z1.9-2003 CONTENTS Page INTRODUCTION . vii SECTION A GENERAL DESCRIPTION
17、 OF SAMPLING PLANS . 1 AQL Conversion Table 5 Sample Size Code Letters 6 Operating Characteristic Curves for Sampling Plans of Sections B. C. and D (Graphs for Sample Size Code Letters B through P) 6 SINGLE SPECIFICATION LIMIT 32 Examples: Example of Calculations: Single Specification Limit-Form 1 .
18、 34 Example of Calculations: Single Specification Limit-Form 2 . 35 Master Table for Normal and Tightened Inspection (Single Specification Limit-Form 1) 36 Master Table for Reduced Inspection (Single Specification Limit-Forml) 37 Part II DOUBLE SPECIFICATION LIMIT . 38 Examples: Tables: Table A- 1 T
19、able A-2 Table A-3 SECTION B VARIABILITY UNKNOWN-STANDARD DEVIATION METHOD 32 Part I Example B-1 Example B-2 Table B-1 Table B-2 Tables: Example B-3 Example B-4 Example of Calculations: Double Specification Limitane AQL Value for Both Upper and Lower Specification Limit Combined 40 Example of Calcul
20、ations: Double Specification Limit- Different AQL Values for Upper and Lower Specification Limits . 41 Master Table for Normal and Tightened Inspection (Double Specification Limit and Form 2-Single Specification Limit) 42 Master Table for Reduced Inspection (Double Specification Limit and Form 2-Sin
21、gle Specification Limit) 43 Table for Estimating the Lot Percent Nonconforming 44 Values of F for Maximum Standard Deviation (MSD) 53 Appendix B Definitions 54 SINGLE SPECIFICATION LIMIT 55 Examples: Example of Calculations: Single Specification Limit-Form I . 58 Example of Calculations: Single Spec
22、ification Limit-Form 2 . 59 Master Table for Normal and Tightened Inspection (Single Specification Limit-Form I) 60 Master Table for Reduced Inspection (Single Specification Limit-FormI) . 61 Part II DOUBLE SPECIFICATION LIMIT 62 Tables: Table B-3 Table B-4 Table B-5 Table B-6 SECTION C VARIABILITY
23、UNKNOWN-RANGE METHOD . 55 Part I Example C-1 Example C-2 Table C-1 Table C-2 Tables: V ANSUASQ Z1.9-2003 Page Examples: Example C-3 Example C-4 Tables: Table C-3 Table C-4 Table C-5 Table C-6 Appendix C Example of Calculations: Double Specification Limitane AQL Value for Both Upper and Lower Specifi
24、cation Limit Combined 65 Example of Calculations: Double Specification Limit-Different AQL Value for Upper and Lower Specification Limits 66 Master Table for Normal and Tightened Inspection (Double Specification Limit and Form 2-Single Specification Limit) 67 Master Table for Reduced Inspection (Dou
25、ble Specification Limit and Form 2-Single Specification Limit) 68 Table for Estimating the Lot Percent Nonconforming 69 Values off for Maximum Average Range (MAR) . 78 Definitions 79 SECTION D VARIABILITY KNOWN . 80 Part I SINGLE SPECIFICATION LIMIT 80 Examples: Example of Calculations: Single Speci
26、fication Limit-Form 1 . 82 Example of Calculations: Single Specification Limit-Form 2 . 83 Master Table for Normal and Tightened Inspection (Single Specification Limit-Form 1) . 84 Master Table for Reduced Inspection (Single Specification Limit-Forml) 86 Part II DOUBLE SPECIFICATION LIMIT . 88 Examp
27、les: Example D-1 Example D-2 Table D- 1 Table D-2 Tables: Example D-3A Example D-3B Example D-4 Example of Calculations: Double Specification Limitane AQL Value for Both Upper and Lower Specification Limit Combined 90 Example of Calculations: Double Specification Limitane AQL Value for Both Upper an
28、d Lower Specification Limit Combined 91 Example of Calculations: Double Specification Limit-Different AQL Values for Upper and Lower Specification Limits . 92 Master Table for Normal and Tightened Inspection (Double Specification Limit and Form 2-Single Specification Limit) 93 Master Table for Reduc
29、ed Inspection (Double Specification Limit and Form 2-Single Specification Limit) . 95 Table for Estimating the Lot Percentage Nonconforming 97 Value of F (T for Maximum Process Standard Deviation 98 Appendix D Definitions 99 Tables: 1 Matching Code Letters and ANSUASQC Z 1.9-2003 Sample Size . 101 2
30、 ANSUASQC 21.9-2003 Percentage Points in Terms of Percent Nonconforming 102 3 ANSUASQ Z 1.4-2003 (MIL-STD- 105) Percentage Points in Terms of PercentNonconforming 103 4 Difference in Percentage Points-ANSVASQC Z1.9-2003 Minus Tables: Table D-3 Table D-4 Table D-5 Table D-6 SECTION E APPENDIX-MATCH W
31、ITH ANSUASQ Z1.4-2003 100 ANSUASQ 21.4-2003 (MIL-STD-105) 104 vi ANSIIASQ Z1.9-2003 INTRODUCTION This standard was prepared to meet a need for the use of standard sampling plans for inspection by variables in procure- ment, supply and storage, and maintenance inspection operations. The variables sam
32、pling plans apply to a single quality characteristic which can be measured on a continuous scale, and for which quality is expressed in terms of percent non- conforming. The theory underlying the development of the variables sampling plans, including the operating characteris- tic curves, assumes th
33、at measurements of the quality characteristics are independent, identically normally distributed ran- dom variables. It is important to note that variables sampling plans are not to be used indiscriminately, simply because it is possible to obtain variables measurement data. The users are advised to
34、 consult their technical agency to determine the feasibility o f application in considering applications where the normality or independence assumptions may be questioned. In comparison with attributes sampling plans, variables sampling plans have the advantage of usually resulting in consid- erable
35、 savings in sample size for comparable assurance as to the correctness of decisions in judging a single quality char- acteristic, or for the same sample size, greater assurance is obtained using variables plans. Attributes sampling plans have the advantage of greater simplicity, of being applicable
36、to either single or multiple quality characteristics, and of requiring no knowledge about the distribution of the continuous measurements of any of the quality characteristics. This standard is divided into four sections. Section A describes general procedures of the sampling plans. Sections B and C
37、 describe specific procedures and applications of the sampling plans when variability is unknown. In Section B the stan- dard deviation is used as the basis for an estimate of the unknown variability, and in Section C the average range of the sam- ple is used. Section D describes the plans when vari
38、ability is known. Each of Sections B, C, and D is divided into two parts: (I) Sampling Plans for the Single Specification Limit Case, and (II) Sampling Plans for the Double Specification Limit Case. For the single specification limit case, the acceptability criterion is given in two forms: Form 1 an
39、d Form 2. Either of the forms may be used, since they are identical as to sample size and decision for lot acceptability or rejectability. In deciding whether to use Form 1 or Form 2, the following points should be borne in mind. Form 1 provides the lot acceptability criterion without estimating lot
40、 percent nonconfomiing. The Form 2 lot acceptability criterion requires estimates of lot percent nonconforming. Operating characteristic curves in Table A-3 are for the Normal Inspection sampling plans and show the relationship between quality and percent of lots expected to be accepted for the qual
41、ity characteristic inspected. As stated, these operating char- acteristic curves are based on the assumption that measurements are selected at random from a normal distribution. The corresponding sampling plans in Sections B, C, and D were matched as closely as possible under a system of fixed sampl
42、e size with respect to their operating characteristic curves. Operating characteristic curves in Table A-3 have been computed for the sampling plans based on the standard deviation estimate of unknown variability. They are equally appli- cable for sampling plans based on the average range of the sam
43、ple and those based on known variability. Certain characteristics concerning the sampling plans in Section B and C and those in Section D should be noted. Plans based on the estimate of unknown variability require fewer sample units for comparable assurance when the standard devi- ation is used than
44、 when the average range of the sample is used. On the other hand, plans using the average range of the sample require simpler computations and may be better understood by operating personnel. Plans using known variability require considerably fewer sample units for comparable assurance than either o
45、f the plans of unknown variability; however, the requirement of known variability is a stringent one. The user is well advised to consult a statistician before applying sampling plans using known variability. vii ANSI/ASQ Z1.9-2003 Table B-6 provides values of the factor F to compute the maximum sta
46、ndard deviation: MSD. The MSD serves as a guide for the maximum allowable magnitude of the estimate of lot standard deviation when using plans for the double specifica- tion limit case, based on the standard deviation. Similarly Table C-6 provides values of the factor f to compute the maxi- mum aver
47、age range: MAR. The MAR serves as a guide for the maximum allowable magnitude of the average range of the sample when using plans for the double specification limit case, based on the average range. The estimate of lot standard deviation or average range of the sample, if it is less than the MSD or
48、MAR, respectively, helps to ensure, but does not guar- antee, lot acceptability. All symbols and their definitions are given in the appendix of the applicable section. An illustration of the computations and procedures used in the sampling plans is given in the examples in Parts I and II of the appl
49、icable section. The computations involve simple arithmetic operations such as addition, subtraction, multiplication, and division of numbers, or at most, the taking of a square root of a number. The user should become familiar with the general procedures of Section A, and refer to the applicable section for detailed instructions regarding specific procedures, computations, and tables for the sampling plans. Section E-Appendix provides information about the match between this variables standard, ANSI/ASQ Z1.9-2003, and the corresponding attributes standard, ANSI/ASQ Z 1.4-2003. The flowc
链接地址:https://www.31doc.com/p-3732425.html