ASME B18.18.1 pdf download Inspection and Quality Assurance for General Purpose Fasteners
1 GENERAL INFORMATION
1.1 Basic Plan Structure This Standard outlines a Quality Assurance Plan for internally and externally threaded fasteners and acces- sories or associated parts. Provisions are included for sampling plans, inspection frequencies, control proce- dures, and record keeping. Included in this plan are fasteners for general purpose applications, such as those where hand assembly is employed and cost is probably of prime consideration. This plan relies on judicious manufacturing controls and inspections by the producer and, should a dispute arise, provides an inspection plan for lot compliance after shipment. This Standard will be used in conjunction with other accepted standards for product, testing, gaging, and material; therefore, those provisions, as well as packag- ing, are not included herein.
1.2 Inspection Levels The substantial difference in importance to the user of various characteristics and the dissimilar degrees of control in manufacture make impractical the subjecting of all characteristics to the same degree of inspection. Therefore, three inspection levels have been provided. Any additional characteristics deemed applicable by the user that do not appear in the plan shall be explicitly designated by the user, preferably on engineering draw- national or international Standard. All calibration proce- dures shall comply with the requirements of ISO 1 7025, General Requirements for the Competence of Testing and Calibration Laboratories.
1.3 Lot Sizes When the acceptance number for sampling by attri- butes is fixed, variation in sample size results in variation of acceptable quality. Therefore, to avoid this inconsist- ency, fixed sample sizes are applied for the greatest range of lot size. Sample sizes for lots up to 250,000 pieces are shown in Table 1 ; however, for lot sizes exceeding 250,000 pieces, Table 1 , Note (2) shall apply.
1.4 Measuring and Testing Equipment All inspection and testing equipment shall be cali- brated and traceable to the National Institute of Stan- dards and Technology (NIST) standard or an equivalent 1.5 Basic Plan Outline The basic plan outline as shown in Fig. 1 is included to enhance understanding and use.
1.6 References The following is a list of publications referenced in this Standard. ASME B1 .3M, Screw Thread Gaging Systems for Acceptability — Inch and Metric Screw Threads (UN, UNR, UNJ, M, and MJ) Publisher: The American Society of Mechanical Engineers (ASME), Three Park Avenue, New York, NY 1 001 6-5990; Order Department: 22 Law Drive, P.O. Box 2300, Fairfield, NJ 07007-2300 ISO 1 7025, General Requirements for the Competence of Testing and Calibration Laboratories Publisher: International Organization for Standardiza- tion (ISO), 1 rue de Varembe´, Case Postale 56, CH-1 21 1 , Gene`ve 20, Switzerland/Suisse ings and related specifications by the appropriate code 2 GENERAL PURPOSE FASTENERS letter at the time of ordering (see Nonmandatory Appen- dix B). To assist in arriving at the most appropriate inspection level, the Decision Table included in Non- mandatory Appendix A is recommended for guidance.
2.1 Scope This Standard outlines the inspection plan to be employed when lot compliance after shipment of gen- eral purpose fasteners is questioned by the user. The producer is responsible for supplying a product of satis- factory quality through judicious manufacturing con- trols and inspection.
2.2 Applicable Characteristics The general plan outlines the significant applicable characteristics that are described by related specifica- tions and engineering drawings. Three levels of inspec- tion — A, B, and C — are employed. Each characteristic is assigned an appropriate level. These characteristics and corresponding inspection levels are listed in Tables 1 through 3 for various types of products.