7 o8 `; p% n" PASME Y14.5 - 2009出现了一个新术语MMB “Maximum Material Boundary 最大实体边界”，跟以往的MMC “Maximum Material Condition 最大实体条件”有什么区别？% x S/ x0 Q: H The Maximum Material Boundary (MMB) is a new term used in the 2009 standard and replaces the terms "Maximum Material Condition" and also "Virtual Condition Size" when referring to a datums referenced with the maximum material condition symbol. In certain cases, MMB is the maximum material size while in other situations, it is the virtual condition size. It depends upon whether the datum is a primary, secondary or tertiary datum. In other cases, it could be the virtual condition size of the FRTZF rather than the larger tolerance shown in the PLTZF., e% I5 D3 j6 L# r# o
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补充问题：这句话怎么翻译才合适？ & |6 Z% o. n! u s- QALL POSITION TOLERANCES APPLY AT MMC OR MMB. ENVELOPE REQUIREMENT APPLIES.( e; e& K9 [+ } 作者: 原谅我今天 时间: 2012-8-28 12:12
我不清楚这两者之间有什么本质区别。但是从我的经验来看，在描述基准特征时一般用MMB，而对被测的尺寸要素来说一般都用MMC。6 i' n8 [+ l! Y+ G- o1 W