Profile of a surface questions

[justinthorne76]

Have a quick question on how PC-DMIS calculates the surface profile dimension. Im am trying to do the profile of a vibra-weld rib on a part, the print calls out a few distances between lines, radii, and distances from origin. When I go to dimension any of these features they are not available to select from to form the feature control frame, only points. So I created a point from every single hit I took of the locations (like cir1.hit[1]) and then dimensioned all of the points. Without really being able to see how PC-DMIS calculates this I am unsure about using this as my recorded measurement and have just been doing it the old way of dimensioning all the features and recording the largest deviation times 2. I was curious if someone could give some insight on how this is calculated, why wont it let me pick features only points, and if using all the points is accurate. Thanks.

[Nano Vujkovic]

What kind of features are you picking up, and what kind of profile are you measuring? For example, you can't measure a surface profile of a circle!!!

[ir a programmer]

Basically -

• Construct a Set from individual points for the applicable feature
• Dimension a Profile the Set according to the drawing FCF
  - Form or Form and Location
  - ISO or ASME Tolerances

The Profile value is calculated differently depending on how it is set up. If you can provide a specific example, a specific answer can probably be provided.

This subject comes up pretty frequently, there should be other threads that might answer your question(s) as well.

[BIGWIG7]

you can't measure a surface profile of a circle!!!

why not?

[John Riggins]

What kind of features are you picking up, and what kind of profile are you measuring? For example, you can't measure a surface profile of a circle!!!

Yes you can. Try it.

[Nano Vujkovic]

I guess in Legacy mode you can, but i never had luck using profile of a surface on circles, lines,... In Xact, linear features won't even show up for selection. So that's why!!!

[John Riggins]

I guess in Legacy mode you can, but i never had luck using profile of a surface on circles, lines,... In Xact, linear features won't even show up for selection. So that's why!!!

I have used it quite a few times.
It can be very helpful when trying to determine the exact nature of form problems, like out of round, taper, etc.

[Nano Vujkovic]

I have used it quite a few times.
It can be very helpful when trying to determine the exact nature of form problems, like out of round, taper, etc.

Or just get T values for each point. You can also use circularity for "out of round" and angularity for a taper, but i would still be skeptical of using a surface profile on a linear feature.

[BIGWIG7]

I guess in Legacy mode you can, but i never had luck using profile of a surface on circles, lines,... In Xact, linear features won't even show up for selection. So that's why!!!

you said it with such conviction i thought i had been doing something wrong all these years.

[Obelix]

I guess in Legacy mode you can, but i never had luck using profile of a surface on circles, lines,... In Xact, linear features won't even show up for selection. So that's why!!!

For profile of the line or circle, 2D features, you have to select "Profile of the Line" first, then you will have option to pick them. If you select "Profile of the Surface" first, PcDims will not give you an option to pick 2D features.

[Nano Vujkovic]

you said it with such conviction i thought i had been doing something wrong all these years.

which part???

[Nano Vujkovic]

For profile of the line or circle, 2D features, you have to select "Profile of the Line" first, then you will have option to pick them. If you select "Profile of the Surface" first, PcDims will not give you an option to pick 2D features.

Not really sure what you mean by this?

[sealevel]

not too sure that a circle can be considered for profile of a surface. (where's the surface? )
but profile of a line? NOW we're talking......

[Obelix]

Even if your print is asking for Profile of the Surface, but you measured as a single line scan, you have to use Profile of the Line in PcDmis to have the option of selecting it.

[sealevel]

Even if your print is asking for Profile of the Surface, but you measured as a single line scan, you have to use Profile of the Line in PcDmis to have the option of selecting it.

+1

simply put:

----------------- LINE


-----------------
-------------- SURFACE
----------

(i concur)