hexagon logo

TP Manual Calculation z,y,z

Hi guys,

Basically I'm measuring a bunch of parts for a capability study. Long story short I need to get true position on four similar features. For this instance I'm not sure how to accurately pull this off with the feature inside PC-DMIS since I'm trying to get it from 3 midpoints (1 in x, 1 in y, 1 in z). I figure I can use all the deviations and export the numbers into my excel and just formula it out. I would think the formula for a radius of a sphere would be the same for true position where TP would be the same as r. In that case r^2=x^2+y^2+z^2, or TP = SQRT(x*x+y*y+z*z). But on another forum post I saw, TP = SQRT(x^2+y^2++z^2)*2. What gives with the *2? They said that was for a circle? My shape is virtually a rectangular box. I don't understand how the middle of one object could be different from the middle of another object if it's "borders" were arranged differently?


Would, TP = SQRT(xdev^2+ydev^2+zdev^2), be the correct formula for getting TP on a rectangular box relative to called out datums?


Thank you guys!
Parents
  • DaSalo, I think you mean it is a bidirectional tolerance zone.

    In frop1's case, each axis should have a bidirectional zone defined (x,y,z).

    Each needs to be reported.
    2*Xdev
    2*Ydev
    2*Zdev

    His formula SQRT(Xdev^2+Ydev^2+Zdev^2) = RADIUS of a spherical tolerance zone.


    Maybe you meant to say diametric tolerance zone vs radial tolerance zone.
Reply
  • DaSalo, I think you mean it is a bidirectional tolerance zone.

    In frop1's case, each axis should have a bidirectional zone defined (x,y,z).

    Each needs to be reported.
    2*Xdev
    2*Ydev
    2*Zdev

    His formula SQRT(Xdev^2+Ydev^2+Zdev^2) = RADIUS of a spherical tolerance zone.


    Maybe you meant to say diametric tolerance zone vs radial tolerance zone.
Children
No Data