MMC & LMC modifiers and CMM measuring techniques like diameter least squares and circularity or minimum/ maximum diameter

Marco Bernardi

Mark_Navigator
Dear all,

is there a relation about new dimensions modifiers like MMC and LMC and measurements techniques?
For example, if I've to verify an hole with the MMC symbol on a roundness tolerance, which kind of measurement strategy has to be used for?
Least squares and circularity or minimum diameter?
 

optomist1

A Sea of Statistics
Super Moderator
Hi Marco, a screen shot or drawing will help insure we are on the right path...please share...

Optomist1
 

Marco Bernardi

Mark_Navigator
The request is generic, however the following picture can be a good example, referring to quote 1 and 60: (is right also then, to have linear dimensions with only value and tolerance, and no specifications about strategy to verify it?)

1597731460680.png
 

Cari Spears

Super Moderator
Leader
Super Moderator
That is correct. Modifiers are not applied to form tolerances. Modifiers may be applied to position, and may be applied to orientation and profile tolerances if it is a size feature.
 

Cari Spears

Super Moderator
Leader
Super Moderator
The request is generic, however the following picture can be a good example, referring to quote 1 and 60: (is right also then, to have linear dimensions with only value and tolerance, and no specifications about strategy to verify it?)
This does appear that you added the MMC symbol and extended the feature control frame in your snip. Is your question because you have actually seen a material modifier on a roundness or cylindricity tolerance?

What do you mean by "no specifications about strategy to verify..."?
 
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