关键词: 最大实体要求, 检验方法, 偏差表示, 补偿方法

Abstract: To improve the parts'percent of pass,the geometric tolerance of measured feature was compensated by the deviation of datums deviated from the Maximum Material Condition (MMC) under the condition of following Maximum Material Requirement (MMR).A general representation and compensation method of datum's deviations was proposed to solve the problem of compensation for parts'geometric deviation inspection.The relative position between the Datum Feature Simulator (DFS) at actual condition and the datum boundary at MMC was determined according to the determination method of DFS,and the relative position boundary between design Datum Reference Frame (DRF) and measurement DRF were obtained.For the datum combination of cylinder and slot which were subjected to the maximum material requirements,the relative position boundary between design DRF and measurement DRF was represented by combined mechanism of crank-guide bar and oscillating bar.The deviations of datum were represented by the crank length and the oscillating angle of the oscillating bar,and the crank length was the increment of compensated value for tolerance feature,the oscillating angle was used to modify and enlarge the tolerance zone of the tolerance feature.An example was used to demonstrate the implementation of the proposed method,and the precision class relation among these datums was discussed.

Key words: maximum material requirements, inspection method, deviation representation, compensation method