ANSI/ASME B18.18-2011
Quality Assurance for Fasteners

Standard No.
ANSI/ASME B18.18-2011
Release Date
2011
Published By
American National Standards Institute (ANSI)
Latest
ANSI/ASME B18.18-2011
Scope
This quality focused Standard establishes in-process and final inspection requirements for fastener products as well as a receiving inspection plan for fastener purchasers. The Standard identifies four categories, recognizing that fastener users have widely varying requirements. In the preparation of this standard it was recognized that its function must enable it to be a part of the various regimens in use today that attain certain quality levels of products. This standard was written to encompass frameworks that enable the user to pinpoint which approach they wish to use in meeting their own objectives. This standard places a C=0 expectations on the sample plans shown herein, and the sample sizes are smaller for that reason. However it should be recognized that zero nonconformities in a sampling does not necessarily mean that the population was entirely free of defects. This standard recognizes that some well established standards may continue to use C=1 or higher acceptance numbers, and that their sample sizes are higher as a result. When the consumer prefers to use those plans that constitute their requirements, their plans can supersede the sample sizes herein. However the quality expectation of C=0 is still required. Statistical process control and other variation lowering measures can significantly reduce the number of nonconformities in the population that may be produced, but it should be noted that statistical indices only imply the quality level produced, and improperly applied statistical treatments will imply the presence of nonconformities that are not present, or miss some deficiencies altogether. The closest that one can approach the zero population deficiencies state is in 100% part per part examination, but again caution must be exercised. The goal of zero here can be intractable and - the complexity of resources required, - the limitations of the available equipment for each verified characteristic, - the stringency of controls required, will only be able to demonstrate quality on a parts per million basis, and not necessarily any assurance of zero deficiencies.

ANSI/ASME B18.18-2011 history




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