GB/T 40742.3-2021

This standard specifies the verification methods for functional gauges and fixtures used to check compliance with maximum material requirement (MMR) and minimum material requirement (LMR) as defined in geometrical product specifications (GPS). It is applied in manufacturing quality control and dimensional metrology, particularly for verifying the acceptability of workpieces with tolerances that allow material condition bonuses, such as in automotive, aerospace, and precision engineering industries. The standard ensures that gauges and fixtures correctly simulate assembly conditions to confirm that parts meet functional fit requirements under extreme material conditions.