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We are working on a new part that has a surface profile callout of .040mm "between K and L". "K" and "L" are not datums but rather just a couple different spots on the part. Within this "K and L" area there is a 4mm radius (basic dimension). Our customer sent us a part that they have machined to show us what the part should look like. We have checked that radius in particular and it is much closer to 6mm rather than 4mm. I talked to the CMM programmer at the customer and he said that because the 4mm is a basic dimension, as long as the surface profile of that area falls within the 0.40mm, then the size of that radius does not matter.
I've seen this as far as true position is concerned where the basic dimensions give me an idea where my x and y should be, and usually they have to be pretty close to the callout or the true position goes out of tolerance. It seems this would hold true of surface profile as well, but a 6mm radius rather than 4mm seems like a big jump. I'd rather not nod in agreement with his assessment and move on. Is there a way to mathmatically figure out how far this radius would have to be out of tolerance before the surface profile would be out of tolerance? Can anyone add anything that may shed a little more light on the subject? Thanks!
I've seen this as far as true position is concerned where the basic dimensions give me an idea where my x and y should be, and usually they have to be pretty close to the callout or the true position goes out of tolerance. It seems this would hold true of surface profile as well, but a 6mm radius rather than 4mm seems like a big jump. I'd rather not nod in agreement with his assessment and move on. Is there a way to mathmatically figure out how far this radius would have to be out of tolerance before the surface profile would be out of tolerance? Can anyone add anything that may shed a little more light on the subject? Thanks!
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