Jump to content

Best Fit using the new GD&T engine


---
 Share

Recommended Posts

I’m not understanding how the new GD&T engine functions when doing a best fit. It’s putting the center of the bolt circle out in left field somewhere so when you look at the nominals they’re not even in the ballpark. I can go into the special functions and offset each feature back to where it’s supposed to be according to the print, but then the actuals really aren’t going to be respective of the best fit. What am I doing wrong?

Link to comment
Share on other sites

Are the actual results showing large positional deviations, or is it just the nominals not matching the print specifications?

Edited
Link to comment
Share on other sites

In the picture below, you'll see Calypso thinks the center of the bolt pattern is located a couple inches above and slightly behind the highest bolt hole in the pattern. Consequently on the report (bottom picture), the nominals are way out in left field. The amount of deviation looks to be correct but when the program actually runs, we won't be able to tell which hole is off, what direction, and how much. The machinist won't have the required information to make the adjustments.

image.thumb.png.b19dc8a54d32b60c3e4fa242434ba761.pngimage.png.3fa3490d1a5a9dfcb02d1544b8abd495.png

Link to comment
Share on other sites

It goes to the center of the DRF. If you only have a Plane as the Primary, then it will go to the center of the plane. Very annoying indeed. 

Link to comment
Share on other sites

Ya, that's what I thought. I'm going to use the constructed bolt circle as the center. Although it won't be a true best fit, it should get me reasonably close.

Link to comment
Share on other sites

 Share

×
×
  • Create New...