JIS-Z-9010-1999-R2005-ENG.pdf

* STD-JIS 2 SOLO-ENGL LYS7 = LiS33bOô O5bô2b7 J IS JAPANESE INDUSTRIAL STANDARD Translated and Published by Japanese Standards Association (IS0 8423 : 1 1 ) Sequential inspection sampling plans by variables for for percent nonconforming (known deviation) standard ICs 03.120.30 Descriptors : sampling tables, inspection, statistical quality control, inspection by Reference number : JIS Z 9010 : 1999 (E) attributes 27 S Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/12/2007 21:47:07 MDTNo reproduction or networking permitted without license from IHS -,-,- STD=JIS Z SOLD-ENGL L7SS 4733b08 05b82b19 728 2 9010: 1999 (IS0 8423: 1991) Foreword This translation has been made based on the original Japanese Industrial Standard revised by the Minister of International Trade and Industry through deliberations at the Japanese Industrial Standards Committee in accordance with the Industrial Standardization Law. Consequently JIS Z 9010:1979 is replaced with JIS Z 9010:1999. This revision has been prepared based on the first edition of IS0 8423 issued in 1991. Date of Establishment: 1962-03-01 Date of Revision: 1999-05-20 Date of Public Notice in Official Gazette: 1999-05-20 Investigated by: Japanese Industrial Standards Committee Divisional Council on Basic Items JIS Z 9010 : 1999, First English edition published in 2000-12 Translated and published by: Japanese Standards Association 4-1-24, Akasaka, Minato-ku, Tokyo, 107-8440 JAPAN In the event of any doubts arising as to the contents, the original JIS is to be the final authority. O JSA2000 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. Printed in Japan Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/12/2007 21:47:07 MDTNo reproduction or networking permitted without license from IHS -,-,- STD-JIS Z 7010-ENGL 1777 m ll733bûô 05bô2b7 ôbll m z 9010 : 1999 (IS0 8423 : 1991) Contents Introduction . 1 General 1.1 Scope . 1.2 Normative references . 1 . 3 Definitions and symbols 1.4 Principle of sequential sampling by variables 2 Choice of sampling plan . 2.1 Factors determining the choice of a sequential sampling plan by variables . 2.2 Particular reservations on the inspection of small lots 2.3 Selection of a sampling plan 2.4 Pre-operation preparations . 3 Operation of a sequential sampling plan 3.1 3.2 Preparing the sampling plan 3.3 Drawing of the sample 3.4 The cumulative leeway Specification of the plan 3.5 Determination of acceptability . 3.6 Operating characteristic curves and average sample size Annex A (normative) Sequential sampling plans corresponding to SO 3951 single sampling plans Annex B (normative) Determination of the parameters of a sequential sampling plan . Annex C (normative) Calculation of operating characteristic curve and average sample size Annex D (informative) Bibliography Page 1 1 1 2 3 6 7 7 9 9 10 18 18 18 28 28 28 34 35 42 44 48 Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/12/2007 21:47:07 MDTNo reproduction or networking permitted without license from IHS -,-,- JAPANESE INDUSTRIAL STANDARD JIS Z 9010 : 1999 (IS0 8423 : 1991) Sequential sampling plans for inspection by variables for percent nonconforming (known standard deviation) Introduction “his Japanese Industrial Standard has been prepared based on IS0 8423, Sequential sampling plans for inspection by variables for percent nonconforming (known standard deviation) issued in 1991 as the first edition without changing the technical contents. The sampling plans in Annex A is scheduled to be added after revising the original International Standard. The portions underlined with dots in this Standard are not stated in the original International Standard. 1 General 1.1 Scope 1 . 1 . 1 This Japanese Industrial Standard specifies sequential sampling plans and procedures for inspection by variables of discrete items. It is complementary to JIS Z 9009. The plans in the main body of the standard are indexed in terms of the producer's risk point and the consumer's risk point. Annex A specifies sequential sampling plans and procedures indexed in terms of the acceptable quality level (AQL) to supplement the system of sampling plans in JIS The purpose of this Standard is to provide procedures based on a sequential assessment of inspection results, that may be used to induce the supplier through the economic and psychological pressure of non-acceptance of lots of inferior quality to supply lots of a quality having a high probability of acceptance. At the same time the consumer is protected by a prescribed upper limit to the probability of accepting lots of poor quality. Z 9015-1. 1 . 1 . 2 The sampling plans in this Standard are primarily designed for use when all of the following conditions are satisfied: a) where the inspection procedure is to be applied to a continuing series of lots of discrete items all supplied by one producer using one production process. If there are different producers, this Standard shall be applied to each one separately; where only a single quality characteristic x of these items is taken into consideration, which must be measurable on a continuous scale. If several such characteristics are of importance, this Standard does not apply; where production is stable (under statistical control) and the quality characteristic x has a known standard deviation and is distributed according to a normal distribution or a close approximation to the normal distribution; where a contract or standard defines an upper specification limit U, a lower specification limit L or both; an item is qualified as nonconforming when its measured quality characteristic x satisfies one of the following inequalities: b) c) d) Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/12/2007 21:47:07 MDTNo reproduction or networking permitted without license from IHS -,-,- STD-JIS Z SOLO-ENGL 1999 4933b08 05bû27L Li12 D 2 Z 9010 : 1999 (IS0 8423 : 1991) x u x u or x on the acceptance chart a) b) c) If the point lies in the acceptance zone, the lot shall be considered acceptable. If the point lies in the rejection zone, the lot shall be considered not acceptable. If the point lies in the indecision zone, another item shall be sampled and inspected. The successive points on the chart may be connected by a step curve to show up If the point is close to the acceptance or rejection lines, the numerical method shall be used to make the decision. any trend in the inspection results. Caution: 3 . 5 . 1 . 3 Example For the sequential sampling plan with L=200 kV, 0=1.2 kV, h=4.312, h=5.536, g=2.315 and nt=49, the acceptance and rejection values were determined in the example given in 3 . 2 . 1 . 3 . The inspection results x for the first 12 insulators sampled from a lot are given in the second column of Fig. 2. The third column gives the corresponding leeway y=x- 200, and in the fifth column the cumulative leeways are recorded. Inspection is continued up to and including the 12th item, since the successive cumulative leeways after inspection of item 1, 2, ., 11 are greater than the corresponding rejection values but less than the corresponding acceptance values. The cumulative leeway after inspection of the 12th item is greater than the corresponding acceptance value and therefore inspection is terminated and the lot is accepted. Note that the lot is accepted although the withstand voltage of the fifth item inspected is below the specified value. It is an inherent feature of a sequential variables sampling plan that only the sample average is used to assess the quality of a lot, and therefore it may happen that a lot is judged acceptable even if some inspection results deviate from the specification by a small amount. Fig. 8 shows an acceptance chart for this sequential sampling plan. The preparation of this chart is described in the example given in 3 . 2 . 1 . 3 . The successive pairs of the cumulative sample size and the cumulative leeway (ncum; y from Fig. 2 have been plotted on the acceptance chart and connected by a step curve. Because the point (i2 ; 38.8) is in the acceptance zone, inspection shall be terminated after inspection of the 12th item, and the lot shall be declared acceptable. Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/12/2007 21:47:07 MDTNo reproduction or networking permitted without license from IHS -,-,- STD*JIS Z 9010-ENGL 1999 4933608 05bA299 5TL 30 Z 9010 : 1999 (IS0 8423 : 1991) va Cumulative sample size Acceptance chart for the sequential sampling plan for a single specification limit considered in the example given in 3.5.1.3 3.5.2 Combined double specification limits 3.5.2.1 Numerical method Compare the cumulative leeway Y with the corresponding upper and lower acceptance values AfU and AfL), and the corresponding upper and lower rejection values RN) and RfL). a) If A%SYSAN), the lot shall be considered acceptable. b) If either Y2Rw) or YSRfL, the lot shall be considered not acceptable. c) If neither a) nor b) is satisfied, another item shall be sampled and inspected. When the cumulative sample size reaches the curtailment value nt, the lot shall be considered acceptable ifAtmSYStcv, otherwise the lot shall be considered not acceptable. 3.5.2.2 Graphical method prepared in accordance with 3.2.2.2. Plot the point (ncum; Y) on the acceptance chart a) If the point lies in the acceptance zone, the lot shall be considered acceptable. b) If the point lies in the rejection zone, the lot shall be considered not acceptable. c) If the point lies in the indecision zone, another item shall be sampled and inspected. The successive points on the chart may be connected by a step curve to show up If the point is close to the acceptance or rejection lines, the numerical method shall be used to make the decision. any trend in the inspection results. Caution: Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/12/2007 21:47:07 MDTNo reproduction or networking permitted without license from IHS -,-,- 31 Z 9010 : 1999 (IS0 8423 : 1991) 3 . 5 . 2 . 3 Example For the sequential sampling plan with L=200 mm, U=210 mm, 0=1.2 mm, h=4.312, h=5.536, g=2.315 and nt=49, the acceptance and rejection values corresponding to combined double specification limits were determined in the example given in 3 . 2 . 2 . 3 . The inspection results x for the first 12 items sampled from a lot are given in the second column of Fig. 4. The third column gives the corresponding leeway, y=x-200, and in the sixth column the cumulative leeway is recorded. Inspection is continued up to and including the 12th item, since the successive cumulative leeways after inspection of item 1, 2, ., 11 satise neither a) nor b) in 3 . 5 . 2 . 2 . The value of the cumulative leeway after inspection of the 12th item is between the corresponding lower and upper acceptance values and therefore inspection is terminated and the lot is accepted. Fig. 9 shows an acceptance chart for this sequential sampling plan. The preparation of this chart is described in the example given in 3 . 2 . 2 . 3 . The successive pairs of the cumulative sample size and the cumulative leeway (neum; Y) from Fig. 4 have been plotted on the acceptance chart and connected by a step curve. Since the point (12 ; 38.8) is in the acceptance zone, inspection shall be terminated after inspection of the 12th item, and the lot shall be declared acceptable. 80 60 40 20 O Cumulative sample size Fig. 9 Acceptance chart for the sequential sampling plan for combined double specification limits considered in the example given in 3 . 5 . 2 . 3 3.5.3 Separate double specification limits 3 . 5 . 3 . 1 Numerical method The acceptability criteria in 3 . 5 . 3 . 1 . 1 and 3 . 5 . 3 . 1 . 2 shall be applied to determine the acceptability for each specification limit separately. The lot shall be considered acceptable and inspection shall terminate if the lot has been considered acceptable with respect to both limits according to 3 . 5 . 3 . 1 . 1 a3 and 3 . 5 . 3 . 1 . 2 a). Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/12/2007 21:47:07 MDTNo reproduction or networking permitted without license from IHS -,-,- STD*JIS Z 9010-ENGL 1777 Li733b08 05bA30L TAT 32 2 9010 : 1999 (IS0 8423 : 1991) 3 . 5 . 3 . 1 . 1 Acceptability criterion for the upper specification limit Compare the cumulative leeway Y with the corresponding acceptance value AN) and rejection value Rw). a) b) c) If YIA(u), the lot shall be considered acceptable with respect to the upper specification limit and inspection with respect to that limit shall terminate. If Y2Rfuj, the lot shall be considered not acceptable and inspection with respect to both limits shall terminate. If neither a) nor b) is satisfied, another item shall be sampled and inspected with respect to the upper specification limit. When the cumulative sample size reaches the curtailment value nt and YAJu), the lot shall be considered not acceptable and inspection shall terminate. When the cumulative sample size reaches the curtailment value nt and YS Atu), the lot shall be considered acceptable with respect to the upper limit. If the lot has already been considered acceptable with respect to the lower limit, or if Y Y) on the acceptance chart prepared in accordance with 3 . 2 . 3 . 2 . The acceptability criteria in 3 . 5 . 3 . 2 . 1 and 3 . 5 . 3 . 2 . 2 shall be applied to determine the acceptability for each specification limit separately. The lot shall be considered acceptable, and inspection shall terminate, if the lot has been considered acceptable with respect to both limits according to 3 . 5 . 3 . 2 . 1 a) and 3 . 5 . 3 . 2 . 2 a ) . 3 . 5 . 3 . 2 . 1 Acceptability criterion for the upper specification limit Copyright Japanese Standards Association Provided by IHS under license with JSALicensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 03/12