Hello,
I am asking for input to how other deal with calibration of profilometers. Presently our company calibrates a roughness specimen patch, then verifies the profilometer against the calibrate specimen.
Does anyone actually calibrate the profilometer (in-house or outside service)?
We have a Hommel Tester T500, the brochure I have, from there website, states, “No calibration required.” I do not understand this, how do I trust the measurement without comparing it to a know standard?

Thanks for the input,
Phil

This will probably age me, but back in the 80's I calibrated some Dektak Surface Profilometers. It was done with a certified Step Height Standard. Basically is is a certified "ridge" on a flat surface, with a known height. These were in the microns (in terms of their size). I am not familiar with the profilometer you mentioned, but my input would be that you are correct. You have to have some sort of traceable standard to know your profilometer is accurate.

You could do a web search for Dektak, Step Height Standards, or "VLSI Standards". The third one (VLSI Standards) is a company in California that makes very good standards (at least they used to). I actually have some of these standards in my garage I grabbed during a factory closure a number of years ago (although I am not trying to sell them here), just a general comment to illustrate my familiarity.

We use a roughness specimen purchased from and calibrated by the manufacturer. This is traceable to NIST and is kept in our lab for the sole purpose of verification of our profilometer.

So far, the method has never been a problem.

It sounds as though the Hommel tester comes with a similar specimen block so you can do your own verifications without sending the tester out for calibration. I am not familiar with that tester so I can't say for sure.

Dave

The previous 2 replies are correct in that you should have your specimen outsourced to a calibration house that has that type of specimen within their scope.
Then you can use the specimen to verify the gage is reading correctly and make adjustments if necessary.

Thank you for your replies, this verifies that I doing this correctly and will satisfy managements’ questions.

Phil