Would you use your company's highest-accuracy CMM to verify class X .0001" gauge pins?

[[Je...]]

.

• In your answer, do not consider the potential workload this would create.

• Only consider if you deem your machine capable of verifying class X .0001" gauge pins.

• Feel free to list your machine and/or its most recent accuracy statement in the comments (uncertainty ratio).

We are considering taking on this project, so I wanted to poll the masses.

.

[[Ri...]]

So who owns the Xenos or an extremely well tuned small Prismo Ultra/Micura?

[[Je...]]

Please sign in to view this quote.

We have an extremely well tuned Prismo Ultra in a controlled lab. I think it can handle the task, but we'll do some MSA before approving the process.

[[Ri...]]

Please sign in to view this quote.

You'd be interested to know that a lot of labs that certify pin gages do not meet a less than 10% uncertainty.

[[Je...]]

Richard,

That is one reason we are considering bringing this in-house. The service we've been using has sent back some questionable results, and I wonder if the barely skilled new hires get assigned to pin gauge calibration.

[[Ri...]]

Please sign in to view this quote.

In my old life, we got burned by a reputable ring gage manufacturer and the 3rd party certification. Sold a lot of bad parts to a customer because the ring gages were used as setting masters for an air gage.

A quick check on our Accura (1.2 micron spec) quickly showed that the gages were not what they were certified at.

It certainly caused a lot of issues and made people question a lot of gages out on the floor.

[[Da...]]

Just left the company, but we had 4 highly tuned micuras (.7 micron machines that calibrate at about 1/2 that number) and YES I wound VERIFY, down to XXX pins and rings. I would never calibrate down to that level, but they could easily verify if it was a reasonable match to the calibration cert.

[[Je...]]

Please sign in to view this quote.

That's an important distinction, Dave. Thanks for highlighting it.

[[Ma...]]

Please sign in to view this quote.

I try not to get hung up too much with the vocabulary of metrology but I have been mired in this particular one in the past. Officially "Gage verification" is I believe what most of the world considers "gage calibration". A gage is considered "calibrated" when it's bias and uncertainty has been determined. A gage is considered "verified" when it's calibration values have been determined to meet some specifications or fitness for use.

😱 I wish there was an exploding head Smilie

[[Ri...]]

I would label it as certification vs calibration.

Certification is what is performed on these pins after they are manufactured. You are saying their dimensions/characteristics are these values. Like Mark said, you are taking into account measurement uncertainty.

Calibration is when something is changed to make it measure or read a certain value.

Ring Gages/Pin Gages typically cannot be calibrated, but they can be certified.

A scale or a CMM is something that is typically calibrated, and it is calibrated with artifacts that are certified with known measurements.

This is also why we try to correct people, and call it probing qualification. We are quantifying the actuality of the stylus, we are unable to change the values.

[[An...]]

i voted for "yes".
but I would only perform a calibration if the laboratory environment is optimal.

Is the humidity optimal?
small climate fluctuations ±0.5 degrees?
Basic calibration of the CCM optimal?

We are a manufacturer of plastic parts and our measurement laboratory in tempered to 22.5 degrees and have a temperature change of ±0.5 degrees with humidity of 50-60%.
These values are optimal for our plastic parts.
Even if our values are stable, I would not do my own calibration of measuring pins at the moment, because our temperature is higher than it should be for metal parts ( 21 degrees ).

[[Ow...]]

I'd be a bit apprehensive about it.
Along with the many previous reasons mentioned, some quality standards require 3rd party (fox not watching the hen house) calibration procedures and then considering the time added to a busy CMM that is not going to be as quick as modern calibration equipment.
For around 50-60K, you can get this_ https://gagemaker.com/precision-gage-ca ... n-systems/.
A bit more expensive but cheaper than a CMM, you can't go wrong with Pratt & Whitney calibration equipment either.

[[Je...]]

Please sign in to view this quote.

Thank you, Owen. I am going to bring that technology up to our team.

You also make good points about machine burden and bias.