if you have a free standing optical comparator (an old cast iron monster) that you move by turning it 180 degrees does it automatically need to be re-calibrated? Or would verification using traceable standards be OK?
It's fitted with a digital read out if that matters.

Hi ScottK,

I'm not an expert on the topic but I breifly looked through the 17025 standard and couldn't find anything saying you need to recalibrate the equipment. IMO you should be able to verify as you stated in your post. Keep good documentation of the change and I would run a GR&R after the move as the verification.

I'm sure there are others in the cove who will weigh in on this.

Bend with your knees when you move it,:lol:

We have one of these old monsters too and I have never had it calibrated outside. I do a yearly verification on it and have never had an issue. Of course we don't use it very often.

I would not think it automatically needs recalibration. As stated just run it through some verifications.

I would suggest doing a GR&R just before moving and again about 24 hrs after moving. Use the exact same parts testers etc. This along with linear verifications should show up any problems.

James

What do you typically perform on the comparator? Does it have plunge gauges for X/Y axis?

Also, do you typically perform any type of magnification verification?

I would not be worried/concerned at all about the calipers. I might perform some type of verification on the magnification to assure nothing got knocked out of place.

If this is something you typically don't do any type of verification on, and you would have to call in a vendor, I wouldn't bother.

Scott,
In my few years as a QAE and working in a standards lab, monument equipment such as a optical comparator usually are levelled for the purpose of minimizing wear on horizontal x-y table. As for the calibration, I would be concerned if the movers knocked anything out of adjustment.

If this is used for verification of production material (non-Engineering or machine shop aide), I would recommend recalibration.

If you have an internal cal lab and a sufficient amount of standards, do a simple re-verification. Otherwise, call in your external cal service guy to verifiy proper setup and operation.

I had a CORDAX moved and they broke the Z-axis limit adjustment. I had to recalibrate completely even after replacing the adjustment component. No telling what else was tweaked.:mad:

Again, if it is important enough, spend the money and get a professional recert.

Radar Q