This is the first time I've tried to attach a file so I hope this works :-)
I’m trying to figure out how to measure a radius correctly with MMC in PCDMIS (see attachment) I use legacy dimensions
This is the first time I've seen MMC applied to a profile tolerance and I may be way off on my interpretation but here is my take on it:
To create the nominal position for feature R75.05, alignment is leveled through the B-D axis and pitched to the rad centre from datum [A] point (where B-D axis pierces datum [A] plane)
The profile surface tolerance of 0.1 would then have to be equally disposed bilaterally about the theoretical surface or perfect form of the surface being R75.05.
The MMC condition is placed after the tolerance value which refers to the feature being measured (R75.05)
Without MMC I would simply measure the R75.05 to +/- 0.05 to be held to the constraints of 0.1 surface profile coming from the theoretical rad centre created from datum [A][B-D]
My question is:
What is the customer asking for here? Where is the bonus tolerance coming from for MMC?
If the rad measures 75 (bottom limit within the constraints) does this allow a bonus of 0.1 making a profile limit of 0.2, and if it measure 75.1 no bonus is given leaving an overall profile of 0.1 seeing it would be at MMC?
I'm totally confused by this, any help or advice would be greatly appreciated
MMC_RAD.jpg
I’m trying to figure out how to measure a radius correctly with MMC in PCDMIS (see attachment) I use legacy dimensions
This is the first time I've seen MMC applied to a profile tolerance and I may be way off on my interpretation but here is my take on it:
To create the nominal position for feature R75.05, alignment is leveled through the B-D axis and pitched to the rad centre from datum [A] point (where B-D axis pierces datum [A] plane)
The profile surface tolerance of 0.1 would then have to be equally disposed bilaterally about the theoretical surface or perfect form of the surface being R75.05.
The MMC condition is placed after the tolerance value which refers to the feature being measured (R75.05)
Without MMC I would simply measure the R75.05 to +/- 0.05 to be held to the constraints of 0.1 surface profile coming from the theoretical rad centre created from datum [A][B-D]
My question is:
What is the customer asking for here? Where is the bonus tolerance coming from for MMC?
If the rad measures 75 (bottom limit within the constraints) does this allow a bonus of 0.1 making a profile limit of 0.2, and if it measure 75.1 no bonus is given leaving an overall profile of 0.1 seeing it would be at MMC?
I'm totally confused by this, any help or advice would be greatly appreciated
MMC_RAD.jpg
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