True position of different probes

[[Jo...]]

I am trying to get the True position of a feature using multiple probes. All of our probes are calibrated and the sigma is very low, although we did not use the same method for all the probes. If we do a alignment with 1 probe and then check the True position is is great( to be expected), but if we us a different probe than the one used for the alignment it is bad. I would think it would come out good allowing for some small differences between probes. We are getting more later 0.001 inch difference. Any ideas?

[[Cl...]]

Where to start? It could be anything really.
I'd start with the stylus themselves. Are any
of them shanking, loose, damaged?

[[SH...]]

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Are you scanning the features??
It can be solved by gauge correction....
Do one thing measure sphere in the reference sphere using each probe with same strategy and evaluation. If you got Different x,y,z values definitely problem in your probes.

[[Ri...]]

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A lot of times when I've seen this it's due to a poor qualification.

[[To...]]

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Does gauge correction also manipulate X Y Z properties of stylus?

[[SH...]]

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I just told an option to check the probe bending.

I think it workout only while scanning.

To answer your question I don't know exactly.

[[Am...]]

Does anyone have any resources on doing gage corrections? some instructions and maybe on what it does behind the scenes?

[[Cl...]]

There should be an attachment on the forum. Have you tried doing a search?

[[Am...]]

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I have and found a couple threads recommending to use it but not a whole lot more then that. I have never had good luck with the search on here maybe im just not searching the right things, I'll keep looking for it.

[[SH...]]

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May be this one you are looking for...

Thanks to Owen Leng.

Gauge Correction Qualification inst.doc

[[Kl...]]

My experience shows that 3 effects are most of time chould be the reason:
1st: Stylus system at e.g. 20 ° C qualified, but we measure at 25 ° C. Depending on the total length and the position in the probe head, elongation becomes noticeable (better use high-quality CarbonFiber extensions, none made of aluminum).
2nd: Stylus system change
The reproducibility of the change is approx. 1 arc second => 1 µm with a probe length of 200 mm. Therefore avoid changing stylus systems.
3rd: Position calulation by outer- or inner tangent element. A different form deviation shifts the centre).

General rule
High-quality stylus components
Very good air conditioning (short-term stability are very important).
Optimized filter and outlier elimination.

[[Am...]]

That looks like just what I was looking for thank you.