Surface Profile Calculation

[[St...]]

Quick question -

I'm performing a surface profile measurement for a patch compound surface from CAD. Deviation points on the surface display a maximum value of 0.080 um, which should give a surface profile measurement of 0.160 um. Instead, the software seems to be quadrupling the maximum deviation and I'm left with a surface profile value of 0.320 um.

Why is the GOM software displaying a surface profile measurement that is 4x the maximum deviation and not the logical 2x maximum deviation? I trust that the correct surface profile measurement is 0.160 um, but it would be nice to have the GOM software show this value.

Thank you,

Stephen

 

[[Be...]]

Hi,

you should control your deviation on the GD&T check via the color representation to get a clear information which points deviates so much.

see this image how to do this:

Hope this helps to get an answer why this value is calculated?

Regards,

Bernd

[[St...]]

Bernd,

Thank you - this answered my question completely. I found out that the software was selecting area a bit outside of the selected patch compound (see dark blue region on my original image), and this area had a point deviation of 0.160 um, which threw off my measurement and confirms the displayed surface profile measurement of 0.320 um.

My solution is to edit the CAD patches to decrease the area selected for the measurement to prevent this higher deviation region from being chosen.

Stephen