evaluating a 45° angle between planes.

[[RP...]]

We're having some trouble agreeing on an angle result.

Depending on what the other plane is, the CMM measures the angle between 43° - 47°

I'm told by the engineer that it's actually a near-perfect 45°. 

The customer uses a 3d scanner and their results are very close to my cmm results.

Is there a super secret way to evaluate angles differently?

Here's a visualization of the chamfer's profile.  I added random datums to constrain the DoF.

 

 

 

[[Ma...]]

If it's just a chamfer, then i would stick to the closest feature to this chamfer. In other words it's local angle

If part is thin it can bend by fixture force or machined features can bend via machining forces. Then chamfer is to none machining force.

So if it's chamfer of a hole - you can compare angle to plane at hole or hole itself.

[[Ma...]]

Can we see what the callout looks like on the print?

[[RP...]]

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Here's a section view.  it's about a half inch in length.

[[Ma...]]

For me this is too small to accuratelly measure.

For 0,5mm chamfer i do only one point in the middle of chamfer.
Make intersection from faces to obtain sharp corner.
Place a touch point and direction set to 45°
From that point place theoretical 3d line and intersect from both sides. Now you can measure distance from both directions.

For our usage is this fine.

[[Ma...]]

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I wouldn't try to do a profile evaluation of it... The first feature would be the top face not any symmetry or anything like that... I would either scan a line on top face and a line on the chamfer itself with 0.010" speed and 0.0175-.020" length... Then just do "Angle Between Features" characteristic...... Have the filtering on and evals be LSQ for both features.....

[[RP...]]

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I've tried line to line angle as well, and get nearly the same thing as the plane to plane angle.

I'm having a hard time understanding the cad evaluation.  Wouldn't the shape of the angle measurement be the same as angularity?  I'm also not sure why the cad eval doesn't change color when the characteristic is out of tolerance.

I'm doing grid scans on the planes.