Reference Only on Gage or Visual Aid

E

elkel

Hello
I would like to find some information about or clarification in regards to Reference Only on gages or visual aids used to make a decision if the product is acceptable or not.

We have some gages that are referenced only and I am told they are not listed on the control plan or just additional to the required gage on the control plan. I thought it should be calibrated but I have some resistance.

I also have some hot discussion on a foreign particle size template that is being used for visual inspection of molded parts showing circles in sizes of .50to 3.00 mm.
These templates are ordered by an external print company, do these templates have to be calibrated or at least a master of the template?

One more question to settle some discussion, is gage R & R required for visual appearance standards?

Thank you for having this forum, it is awesome
Elke

Thank you
 

AndyN

Moved On
Great questions! Firstly, "for ref" is ambiguous. Don't do it. Use a positive means to show status. "Calibrated", "Verify before use" or something which leaves no doubt as to status etc.

Visual aids aren't "calibrated" in the correct use of the term. I'd suggest they fall into the category of "verify before use" and that will mainly be to ensure no damage has occurred in the area being used as a comparison. Scratches, bruising etc.
 

dgriffith

Quite Involved in Discussions
Hello
I would like to find some information about or clarification in regards to Reference Only on gages or visual aids used to make a decision if the product is acceptable or not. We have some gages that are referenced only and I am told they are not listed on the control plan or just additional to the required gage on the control plan. I thought it should be calibrated but I have some resistance.
The term reference implies an authoritative source. A reference document or reference value or reference material measure. It shouldn't be used indiscriminately but companies always do.
We use the term Indication Only and apply labels for gauges and instruments whose indications are not used to make decisions-- pass/fail, in/out, conforming/non-conforming, etc.
I also have some hot discussion on a foreign particle size template that is being used for visual inspection of molded parts showing circles in sizes of .50to 3.00 mm.
These templates are ordered by an external print company, do these templates have to be calibrated or at least a master of the template?
How does your print company verify circle size? Is the line thickness describing the circle part of, or excluded from, the measurement? Are employees trained on how to use? Having REFERENCE dot master (yep, calibrated/verified) would be a good way to check the templates occasionally for continued use or replacement.
One more question to settle some discussion, is gage R & R required for visual appearance standards?
I can't imagine how you are going to do R&R on a picture of me!!:lmao:
 

Hershal

Metrologist-Auditor
Trusted Information Resource
The visual aid from the print company can be calibrated. However, you have to be careful. Years ago, solving this very issue for RAM Optical, I found a broken link in the traceability chain. That used chrome-on-glass scales to calibrate vision CMMs.

If they can calibrate the prints internally with traceability and uncertainties, that is likely the best move. Otherwise, a calibration provider that calibrates optical comparators can likely put the print on an optical comparator, use their standards, and calibrate the print. Last option is the NIST-Affiliate lab Oak Ridge, which was the solution I ultimately used.

However, before calibrating, the question must be asked of whether checking the foreign particles is important or just something nice to do. The answer will drive the need for calibration.

Hope this helps.
 
Top Bottom