hexagon logo
Register Sign in
  • Replies 4 replies
  • Subscribers 32 subscribers
  • Views 78 views
  • Users 0 members are here
Options
Related

Position Error

Richardbeyer87
Good Afternoon all,

I have a question that has been bothering me for a while, I posted a sample of the code. I am measuring the position of 7 cylinders that are pictured in the drawing, (i cannot post the actual drawing forgive the artistry). I align the part to the datum structure, and when I report the locations in the Position Xact measure the holes are varying in distance over the course of the 10" the cylinders run. When I measure the same dimensions with a height stand using my datum C as 0.00" they are all the same distance from the datum. Why am I seeing the error? Datum B and Datum C are not very square to eachother, and datum A about 0.002" perpendicular to both other datums. Is the combination of these errors causing this variation. They vary by about 0.007" in distance and the angle between datum B and C is 90.04°. Thanks For any Help.
Richard
Parents
  • If you want results from your CMM that correlate better with the surface plate, use Legacy Dimensions.

    There are two ways (Legacy and XACT Measure) to report stuff in PCD & each method varies in how it will compute certain dimensions.

    When you use a "Legacy" true position command, it does straight up true position math relative to your current alignment & workplane.

    XACT Measure computes true position per the latest revision of Y14.5M. That procedure tells PCD to do the true positon math you're familiar with but ALSO factor in datum shift as well as rotation. This is why you get slightly different numbers when you lay it out vs use XACT.

    If you...
    A) make sure your alignment is solid...
    B) Use that alignment (and correct workplane!!) to re-evaluate those hole positions....I'll bet you'll line up better.
Reply
  • If you want results from your CMM that correlate better with the surface plate, use Legacy Dimensions.

    There are two ways (Legacy and XACT Measure) to report stuff in PCD & each method varies in how it will compute certain dimensions.

    When you use a "Legacy" true position command, it does straight up true position math relative to your current alignment & workplane.

    XACT Measure computes true position per the latest revision of Y14.5M. That procedure tells PCD to do the true positon math you're familiar with but ALSO factor in datum shift as well as rotation. This is why you get slightly different numbers when you lay it out vs use XACT.

    If you...
    A) make sure your alignment is solid...
    B) Use that alignment (and correct workplane!!) to re-evaluate those hole positions....I'll bet you'll line up better.
Children
No Data
© 2024 Hexagon AB and/or its subsidiaries. Privacy Policy | Cloud Services Agreement