1、 AEROSPACE RECOMMENDED PRACTICE Statistical Product Acceptance Requirements Using Attribute or Variable Lot Acceptance Sampling Plans SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report
2、is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SA
3、E invites your written comments and suggestions. Copyright 2005 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the p
4、rior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: custsvcsae.org SAE WEB ADDRESS: http:/www.sae.org Issued 2005-10 ARP9013/2 FOREWORD To assure customer satisfaction, aerospace industry organi
5、zations shall produce, and continually improve, safe, reliable products that meet or exceed customer and regulatory authority requirements. The globalization of the aerospace industry, and the resulting diversity of regional/national requirements and expectations, has complicated this objective. End
6、-product organizations face the challenge of assuring the quality of, and integrating, product purchased from suppliers throughout the world and at all levels within the supply chain. Aerospace suppliers and processors face the challenge of delivering product to multiple customers having varying qua
7、lity expectations and requirements. The aerospace industry established the International Aerospace Quality Group (IAQG) for the purpose of achieving significant improvements in quality and safety, and reductions in cost, throughout the value stream. This organization includes representation from aer
8、ospace companies in the Americas, Asia/Pacific, and Europe. This recommended practice has been prepared by the Americas Aerospace Quality Group (AAQG). This document standardizes the requirements on statistical techniques for acceptance of product in attribute or variable lot acceptance sampling pla
9、ns for the aerospace industry. The establishment of common requirements, for use at all levels of the supply-chain, by organizations around the world, should result in improved quality and safety, and decreased costs, due to the elimination or reduction of organization-unique requirements and the re
10、sultant variation inherent in these multiple expectations. SAE ARP9013/2 - 2 - TABLE OF CONTENTS FOREWORD.1 1. SCOPE 3 1.1 Purpose3 1.2 Field of Application.3 2. REFERENCES.3 2.1 Applicable Documents .3 2.2 Definitions 4 3. GENERAL REQUIREMENTS 4 3.1 Quality Parameters 4 4. REQUIREMENTS FOR ATTRIBUT
11、E SAMPLING PLANS 4 4.1 General Conditions 4 5. REQUIREMENTS FOR VARIABLE SAMPLING PLANS.5 5.1 Evaluating Lot Quality 5 5.2 Related Requirements .5 APPENDIX A GUIDELINES AND RECOMMENDATIONS FOR SUCCESSFUL IMPLEMENTATION6 SAE ARP9013/2 - 3 - 1. SCOPE: 1.1 Purpose: The purpose of ARP9013/2 is to ensure
12、 conformance for each product characteristic being verified in each lot in the series. ARP9013/2 document specifies a product acceptance system using either attribute or variable lot acceptance methods documented in ANSI/ASQC Z1.4, ANSI/ASQC Z1.9, and “Zero Acceptance Number Sampling Plans” by Nicho
13、las L. Squeglia. 1.2 Field of Application: These plans shall be applied as appropriate for product acceptance to suit the wide array of manufacturing processes used in the production of aerospace products. These are standard tables used in industry primarily for sampling product that is accepted and
14、 used as a series of lots. Requirements for sampling a lot without any use of information from other lots in a series are covered in ARP9013/1. 2. REFERENCES: 2.1 Applicable Documents: The following publications form a part of this document to the extent specified herein. The latest issue of SAE pub
15、lications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1.1 SAE Publications: Available from SAE, 4
16、00 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. ARP9013 Statistical Product Acceptance Requirements ARP9013/4 Statistical Product Acceptance Requirements Using Continuous Sampling, Skip-Lot Sampling, or Methods f
17、or Special Cases AS9100 Quality Management Systems - Aerospace - Requirements SAE ARP9013/2 - 4 - 2.1.2 ANSI/ASQC Publications: Available from the American Society for Quality (ASQ), 600 North Plankinton Avenue, Milwaukee, WI 53203, Tel: 800-248-1946 or 414-272-8575, www.asq.org. ANSI/ASQC Z1.4 Samp
18、ling Procedures and Tables for Inspection by Attributes ANSI/ASQC Z1.9 Sampling Procedures and Tables for Inspection by Variables for Percent Nonconforming N. L. Squeglia, “Zero Acceptance Number Sampling Plans,“ ASQ Quality Press, 611 East Wisconsin Avenue, P.O. Box 3005, Milwaukee, WI 53201-3005.
19、2.2 Definitions: See ARP9013 paragraph 2.3. 3. GENERAL REQUIREMENTS: Applicable requirements defined in ARP9013 shall be followed when using this specification document. This recommended practice provides additional requirements for accepting product produced in repetitive lots. The requirements in
20、the industry standards listed in 2.1 shall be incorporated when applicable. Where alternative statistical techniques are required for acceptance of product in attribute or variable lot acceptance sampling plans, other than those contained herein, those techniques shall meet the requirements of ARP90
21、13/4. 3.1 Quality Parameters: Each sampling plan shall identify a parameter used to control customer risk, and identify the value of that parameter. If the AOQL parameter alone is applied, then switching rules equivalent to or better than those in ANSI/ASQC Z1.4 shall be used. If switching rules are
22、 employed where the LQ parameter is applied, then the LQ value for the lowest level of inspection shall be identified. Estimating these values from OC curves shall be acceptable. See Appendix A for guidance. 4. REQUIREMENTS FOR ATTRIBUTE SAMPLING PLANS: Sampling plans used to satisfy the requirement
23、s of ARP9013 shall explicitly identify the sampling standard(s) on which it is based. As mentioned in ARP9013, the key requirement for any sampling plan is the level of customer assurance provided. That is the level of assurance that an individual characteristic meets requirements. See Appendix A fo
24、r guidance. 4.1 General Conditions: The following general conditions apply to all conventional lot acceptance sampling plans. SAE ARP9013/2 - 5 - 4.1.1 Sampling Plan Criteria: Conventional lot sampling plans allow a lot or batch of product to be accepted based on the inspection of a portion of that
25、lot or batch. To maintain confidence in long term quality of the product accepted by this inspection, the following criteria shall be included in the organizations sampling plan: a. The lot or batch shall be clearly identified and segregated throughout the process of sampling inspection. b. The lot
26、or batch shall be manufactured under the same design requirements and manufacturing conditions. c. The sample size shall be selected with respect to the size of the lot or batch due to conventional lot sampling plans providing different amounts of customer protection for different lot sizes. The sam
27、ple size in lot sampling tables is determined by the use of Special or General Inspection Levels, one of which shall also be selected. The default level shall be General Inspection Level II. See Appendix A for guidance. 4.1.2 Qualification Criteria for Sampling: Prior to the use of sampling plans fo
28、r the inspection of any characteristics, the organization shall ensure that the processes used to manufacture the product demonstrate the ability to produce characteristics that conform to engineering design specifications. 5. REQUIREMENTS FOR VARIABLE SAMPLING PLANS: For the purposes of ARP9013/2,
29、the requirements of variable sampling plans shall be limited to the application of ANSI/ASQC Z1.9 or equivalent. See Appendix A for guidance. 5.1 Evaluating Lot Quality: Inspection by variables requires that a quality characteristic of each unit of product in a sample shall be measured. The accept/r
30、eject decision for the lot shall be made based usually upon the sample mean and some measure of the spread of the sample measurements (e.g., standard deviation or subgroup ranges). The accept/reject decision shall be made after the sample statistics have been used to obtain an estimate of the lot pe
31、rcent defective. 5.2 Related Requirements: Users of variable sampling plans per ARP9013/2 shall follow the requirements of ANSI/ASQC Z1.9 or equivalent. Therefore, an evaluation shall be performed to verify how the data is distributed. See Appendix A for guidance. PREPARED UNDER THE JURISDICTION OF
32、SAE COMMITTEE G-14, AMERICAS AEROSPACE QUALITY GROUP (AAQG) SAE ARP9013/2 - 6 - APPENDIX A GUIDELINES AND RECOMMENDATIONS FOR SUCCESSFUL IMPLEMENTATION The paragraph numbering below is sequenced to follow the noted paragraph and requirements defined in this recommended practice. The guidelines in th
33、is appendix are considered non-mandatory and not subject to compliance audits, but are intended as an aid to the organization for better understanding of requirements, planning, and implementation of statistical product acceptance methods. The authorship of this recommended practice believes that fo
34、llowing these recommendations to the extent possible will enhance the success of statistical applications that affect, improve, and maintain product quality. A.1 GUIDELINE FOR 3.1 QUALITY PARAMETERS: These values are shown in the ANSI/ASQC Z1.4 Tables V.A, V.B, VI.A, and VI.B; in ANSI/ASQC Z1.9 Tabl
35、e A-3; and in Squeglia Table 1-b on page 11 and the curves on pages 19-32. Each sampling plan may identify both the AOQL and LQ values used to control customer risk. ANSI/ASQC Z1.9 is also roughly matched to ANSI/ASQC Z1.4. The matching is sufficient to allow inspection under either standard for sta
36、ted AQLs/AOQLs and Inspection Levels with reasonably equivalent protection. Tables are given in Appendix E of ANSI/ASQC Z1.9 that show differences in protection between it and ANSI/ASQC Z1.4. A.2 GUIDELINE FOR 4 REQUIREMENTS FOR ATTRIBUTE SAMPLING PLANS: This recommended practice deals with three ba
37、sic sampling standards and their international equivalents: MIL-STD-105, ANSI/ASQC Z1.4, and “Zero Acceptance Number Sampling Plans” by N. L. Squeglia. These documents are presented first because most sampling performed since acceptance sampling was invented has been performed under the directions o
38、f one or the other of these very similar documents. ANSI/ASQC Z1.4 is the current key reference document for conventional lot acceptance sampling for product acceptance. It and numerous international standards are virtually identical to MIL-STD-105, the tables from which are used in industries and c
39、ountries worldwide. Squeglias Zero Acceptance Number Sampling Plans are C=0 sampling plans that are widely accepted as providing equivalent customer protection to the ANSI/ASQC Z1.4 plans. A.3 GUIDELINE FOR 4.1.1.D SAMPLING PLAN CRITERIA: General Inspection Level I and the Special Inspection Levels
40、reduce how rapidly the customer protection improves with increases in lot size. General Inspection Level III accelerates this improvement in customer protection as lot sizes increase. SAE ARP9013/2 - 7 - A.4 GUIDELINE FOR 5 REQUIREMENTS FOR VARIABLE SAMPLING PLANS: For inspection purposes, a variabl
41、e feature is considered a characteristic that can be measured and expressed on some continuous scale. Examples are time measured in seconds, minutes, or hours; length measured in inches, feet, or meters; or weight measured in ounces, pounds, or grams. Any variable lot sampling plans other than ANSI/
42、ASQC Z1.9 or equivalent may be considered under the provisions of ARP9013 paragraph 3.9. In comparison with attribute plans, variables sampling plans provide considerably more information regarding the conformance or nonconformance of the particular quality characteristic. For this reason, variable
43、sampling plans have the advantage of usually requiring smaller sample sizes for equivalent assurance as to correctness of decisions to reject or accept a quantity of product. This smaller sampling size is especially important where destructive testing is performed or where the cost of testing each a
44、dditional unit is high. However, if a number of quality characteristics are to be evaluated on the basis of variables inspection, the cost of inspecting each unit in the sample on an individual characteristic basis may be so high that this factor greatly offsets the advantage of sample size. A.5 GUI
45、DELINE FOR 5.2 RELATED REQUIREMENTS: ANSI/ASQC Z1.9 is virtually identical to MIL-STD-414, the tables from which are used worldwide. ANSI/ASQC Z1.9 models the underlying distribution of individual measurements with a normal distribution. Evaluations of how data is distributed may use graphical techniques or a goodness of fit test (for example, Anderson-Darling). Non-normal data may be appropriately sorted or transformed prior to using variable sampling plans.
