Maximum Material Condition (MMC)
Max is watching his weight. He doesn't want to be too fat or too thin. So he has a maximum size he allows himself to be, and he has a minimum size he allows himself to be.
Max refers to his maximum allowable size as Maximum Mutt Condition (MMC). He refers to his minimum allowable size as Least Mutt Condition (LMC). Sometimes he does not care about whether he is at his max allowable size or his min allowable size or anywhere between. He calls this Regardless of Fido Size (RFS).
Humans have the same things with features of size. For an external feature of size, such as that shown below, if the feature of size is at it's largest allowable size (the size in which it contains the maximum amount of material), it's called Maximum Material size (MMC). If the feature of size is at its smallest allowable size (the size in which it contains the least amount of material), it's called Least Material Condition (LMC). Sometimes we don't care if the part is at its MMC size or its LMC size or anywhere in between. We call that Regardless Of Feature Size (RFS).
Max refers to his maximum allowable size as Maximum Mutt Condition (MMC). He refers to his minimum allowable size as Least Mutt Condition (LMC). Sometimes he does not care about whether he is at his max allowable size or his min allowable size or anywhere between. He calls this Regardless of Fido Size (RFS).
Humans have the same things with features of size. For an external feature of size, such as that shown below, if the feature of size is at it's largest allowable size (the size in which it contains the maximum amount of material), it's called Maximum Material size (MMC). If the feature of size is at its smallest allowable size (the size in which it contains the least amount of material), it's called Least Material Condition (LMC). Sometimes we don't care if the part is at its MMC size or its LMC size or anywhere in between. We call that Regardless Of Feature Size (RFS).
The converse is true with internal features of size such as holes or slots. If Max digs a hole in a mound of dirt, he may dig a wide hole or a narrow hole. If he digs a narrow hole, then the mound of dirt still contains a maximum amount of dirt. So he calls that Maximum Mound Condition (MMC). If he digs a wide hole, then the mound contains a minimum amount of dirt. He calls that Least Mound Condition (LMC). Sometimes he just doesn't care whether the the hole is at its max allowable size or its min allowable size. His master will find the right amount of dirt to fill it in again anyway. So he calls that Regardless of Fill size (RFS).
Humans have the same thing with holes and slots. If the hole is at its smallest allowable size, the part will still have the maximum amount of material. So it's called Max Material Condition (MMC). If the hole is at its largest allowable size, the part will have a minimum amount of material remaining. So it's called Least Material Condition (LMC). If we don't care whether the hole is at its largest allowable size or its smallest allowable size or anywhere in between, we call that Regardless of Feature Size (RFS).
Humans have the same thing with holes and slots. If the hole is at its smallest allowable size, the part will still have the maximum amount of material. So it's called Max Material Condition (MMC). If the hole is at its largest allowable size, the part will have a minimum amount of material remaining. So it's called Least Material Condition (LMC). If we don't care whether the hole is at its largest allowable size or its smallest allowable size or anywhere in between, we call that Regardless of Feature Size (RFS).
Sometimes we want a particular Geometric Tolerance to apply only when a part is at its MMC condition. We can indicate this by using the MMC modifier. The MMC modifier is a circle with and M inside it. The MMC modifier gets inserted into the second box of the feature control frame as shown below
