Traceability of laser based x-y measuring machine

greif

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Given that a laser interferometer based (x-y linear distance)measuring machine has a fundamental standard built into it, some would say that the machine is inherently traceable. Since there are many ways for inaccuracies to creep in (laser not parallel to guideways, straightness, etc.) it would seem that to be traceable the machine must be tested by measuring stage travel in the measurement plane by a calibrated scale or calibration laser.

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Ninja

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fundamental standard built in...what is that?
inherently traceable would be quite a feat...

Being that there is motion involved that directly affects the result (and even if it didn't), I would be looking for a measurement standard and claim traceability through that.

JMO
 

Ninja

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For the wavelength of that type of light...sure.
But you are also mentioning stage travel and alignment.

The letter can be evidence to support that the light source does not need calibration, and that interferometry using it need not be.

Is that the only factor in your length measurement?
If not, as you mention, I would default to a comparison standard which is traceable.

Again, JMO
 

howste

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Given that a laser interferometer based (x-y linear distance)measuring machine has a fundamental standard built into it, some would say that the machine is inherently traceable. Since there are many ways for inaccuracies to creep in (laser not parallel to guideways, straightness, etc.) it would seem that to be traceable the machine must be tested by measuring stage travel in the measurement plane by a calibrated scale or calibration laser.

Comments?
Alternatives?

I don't claim to be an expert on this type of equipment, but here's what I've seen used for this: An artifact (standard part) is measured by a calibrated CMM at certain points, and then the same artifact is measured with the laser interferometer. The difference between the two measurement methods is evaluated.
 
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