最大实体边界跟最大实体条件有什么区别
本帖最后由 metalstorm 于 2012-8-28 11:38 编辑ASME 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?
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.
补充问题:这句话怎么翻译才合适?
ALL POSITION TOLERANCES APPLY AT MMC OR MMB.ENVELOPE REQUIREMENT APPLIES.
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。
至于下面那句话其实很简单,等于说:所有位置度公差值应用于要素的最大实体状态,且遵循包容要求。 我们互换性课程上讲的:最大实体边界就是轴的最大极限尺寸,孔的最小极限尺寸,应该是这样的。还有一个最大实体实效边界就是轴的最大极限尺寸加上公差值,空的最小极限尺寸减去公差值。我记得是这样,你可以再查查是不是,我记得是这样的。
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