2 Curve issues, Curve actuals vs Feature actuals and Profile problems

[[Mi...]]

(metric) 1st issue I am having:

Created Curve_001 of a 5mm radius, 10 points from model
results: Min -0.0045 , Max +0.0120 for a Form of 0.0170
Best Fit, measured points

Customer wants radius so I created Circle_01 using same alignment and points from Curve_001
results: Min -0.0014, Max 0.0017 for a Form of 0.0041

I also created a Feature Circle _02 entering the XYZ and D nominals (10 points)
Results: Min -0.0014, Max 0.0012 for a Form of 0.0027

Diameter actuals being within 0.005 of each other for the Circles

Why are the actuals for the Curve so different? I've rotated the part on my rotary table and get similar results at differing RT positions.

[*][*][*][*][*][*][*][*]

Second issue is Line Profile of the Curves. No matter what I do I cannot get the results for not show the probe radius, example:
Profile: -0.3941 and -0.2325* (0.800 diameter)

*this number really throws me off

[[Ma...]]

Hi Mike,

for clarify: [list=1]

created curve is from model by selecting edge or cut, right?

created features ( circles ) are created same way ( selecting edge / cut ) or is it's nominals recalculated from curve?

if it's recalculated - have you done that before measured curve?

are you reporting actuals from circles with locked nominals ( X,Y,Z,D, vectors )?

For your second problem with curve and probe radius.

• Are nominals as they should be or they are with probe radius?
• Do you have correct vectors ( inside/outside )?

Did you have any curve/ff training or how familiar are you with curves?

[[Mi...]]

1. yes, Curve created by section using alignment for that feature, then extracted by picking Curve and entering how many point per Curve segment
2. 1st created Circle is referencing the above Curve points.
3. 2nd created Circle is using drawing driven dimensions, example X0, Y100, Z-10, D10

Nominal are not locked (do you mean using Formula as in 0+0, 100+0, -10+0 and 10+0?

My thinking is that the Curve, the Circle based on the Curve points and the individual Circle should have same or within a few microns for the Form, something with filtering or settings in Curves I am missing.

Yes I took Curves last year, going thru my notes and plan on reading the Curves manual a little more toughly this time.

[[Ma...]]

Locking nominals is done in evaluation window, where you check which nominal you want to have fixed.
For example you can scan only 10° of a circle d30 - this can give you d20 - d50 - by locking Radius you are forcing Calypso to fit circle with radius 15 into measured points instead of calculating.

In your case - curve is calculating deviations from nominals, but your circles actuals changes ( new X,Y,Z, radius ) to be as close as measured points can give. Here are your differencesbetween curve and circles.

[[Mi...]]

Thank you,

I figured out the profile problem with the Curve. I used Curves Form, it outputs the min/max & Form and allows to see the the plot as well if you want.