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Understanding Profile of A Line Report

Looking for clarification on how PC-DMIS reports the profile of a line values.

The part in question is a cylindrically symmetrical curve, with a cross section cutout listed as a profile of a line between point A<->point B. No datum structure on the control frame. Profile limit .060"

When getting a report trying to get a best-fit result, I usually expect the min and max values to be similar, and according to the online help https://docs.hexagonmi.com/pcdmis/2020.2/en/helpcenter/mergedProjects/core/geometric_tolerances/Profile_of_a_Line.htm
Setting min/max should find the smallest tolerance to fit all the points, but it shows -.016" to +.034" range.

The initial line of the report shows that it is only using .050" of the .060" tolerance but also is out of tolerance, not helping my confusion.

Taking the actual points reported and running them with the other softwares we have at our facility, I have more experience in and can get the even split of the deviations (-.023"<->+.019") or an overall lower profile (-.013"<->+.025") with another

So is there a simple answer to the following questions
1) is the profile good at the initial .050" reporting, even though it is listing it .004" over?
2) Is there a obvious reason that the min max in not having all the point inside the tolerance window.







Parents
  • Appreciate the break down on ISO/ASME reporting!

    Regardless of the math and reporting, your max hit is .034 and you are allowed +/- .030, so you have a problem with the area around hit 5.

    The part I'm struggling with to understand is why is the software not able to adjust to tolerance zone by .004" to -.020+.030 range as there is no datum structure being applied. As I read and understand the max min setting it was to place all the points in the smallest best fit zone, which I thought was the original .050" output, until the breakdown shows otherwise.




  • Because as a cylinder, any adjustments in one direction results in the same amount of movement in the opposite direction on the other side of the cylinder.
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