Dear frineds


what is the difference between calibration and verification ?


and what about Gauge is it calibrated ? and how ?

I'm from aerospace sector: I see calibration as the initial action whereby it "sets the baseline" for a piece of equipment (typically) against a known standard in controlled conditions - in a certified laboratory or other certified facility. This is the most formal method. It can then be used with confidence for all future verifications (measurements), usually in uncontrolled conditions, until an established schedule would require it to be calibrated again (under a periodic recalibration schedule). This cycle repeats for the life of the piece of equipment. Again, this is all quite formal.

If you are talking about simply verifying the same piece of equipment at time of use, this may be to check that basic functions are in working order. Checking for any obvious defects which might indicate possible malfunction. This might even entail testing the gauge over a range of values and compare the results to a known/expected value. This is similar to "calibration", but perhaps could be argued that it is not quite as formal. It would depend on what your quality system allows, what the gauge is used for, whether personnel are trained, what your customer requires from you and such...

~hope this helps a bit~

i understand that from you and please correct me

when i have 5 thermometer . if i send one of them to calibrate outside it will be calibration and when i calibrate the another 4 meter inside it will be verification

is it right ?

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i have gauge to check the conformity of product ( go or no go )
how i can calibrate these one ?

Difference between Calibration & Verification (http://Elsmar.com/Forums/search.php?do=process&titleonly=1&query=difference+calibration+verification)

Calibrate Go/NoGo gage (http://Elsmar.com/Forums/search.php?do=process&titleonly=1&query=calibrate+nogo)

you would have to show your "verification" process is robust and repeatable regardless of who performs it. in principle this is verifying the other 4 thermometers are fit for use, as they are measured against a calibrated piece of equipment (assuming they pass the verification to within a defined tolerance) but they are still not certified ie. they have not been calibrated by a certified facility/body. They may only be used as indication or reference only. It would depend a lot on how you define your process for accepting product.

in short: go/no-go gauges should also be calibrated and certified by an external facility as they accept product.

added:see above links by harry for more discussion (I should've known!)