Hi all,
Who can help me to explain the difference between "calibration","verification","adjust"? Can you give me a example?Thanks

Hi all,
Who can help me to explain the difference between "calibration","verification","adjust"? Can you give me a example?Thanks

Huan Ying (Welcome) Landy,

We had extensive discussions on these terms over here. If you do a search, you'll find many related threads including the following:

Calibration vs. Verification of Calibration vs. Verification - Definitions (http://elsmar.com/Forums/showthread.php?t=22944&highlight=calibration+verification+adjust)

Calibration? Verification? Is this a calibration? (http://elsmar.com/Forums/showthread.php?t=14849&highlight=calibration+verification+adjust)

Calibration vs. Verification - Definition of (http://elsmar.com/Forums/showthread.php?t=3905&highlight=calibration+verification+adjust)

I find the definitions in this attached document to be acceptable also.

I find the definitions in this attached document to be acceptable also. Thanks, Harry. BTW - I changed the document name to Calibration Definitions.pdf so it shows up alphabetically with respect to Calibration in the Attachments Listing. I apologise for nit picking the name... But, you know me! ;)

I thought about this a bit, and I thought Adjustment isn't brought up a lot. The things to remember about adjustment are whether the instrument was Out of Tolerance or not when the device (gage, instrument, etc.) is adjusted. Often, the device is within tolerance, but has to be adjusted to be 'centered' upon a specific measurement unit.

Thanks, Harry. BTW - I changed the document name to Calibration Definitions.pdf so it shows up alphabetically with respect to Calibration in the Attachments Listing. I apologise for nit picking the name... But, you know me! ;)

Not at all, Marc. For the benefit of those who do not understand what we are talking about, Marc is particular about all these little details and spends time taking care of it in the interest of facilitating searches by users of the forum.

I thought about this a bit, and I thought Adjustment isn't brought up a lot. The things to remember about adjustment are whether the instrument was Out of Tolerance or not when the device (gage, instrument, etc.) is adjusted. Often, the device is within tolerance, but has to be adjusted to be 'centered' upon a specific measurement unit.

Yes! Adjustment is not discussed a lot, but is important. Different calibration entities have different policies about adjustment. For example, many make adjustments (wherever possible) if it is 50% of allowed tolerance. Many places only adjust if it is out of tolerance. Some places always adjust regardless of the percent deviation.

Assuming you have someone competent calibrating your equipment, two things to me are worth the money: 1) obtaining as-found data, and 2) having equipment adjusted for maximum accuracy. By always having the instrument adjusted, error creep can be minimized and reducing calibration failures due to accumulated error over time.

By analyzing the data one can make informed decisions about adjusting the calibration interval, granting cost savings that will exceed the data/adjustment extra charge.

Not forgetting, too, that some equipment can be calibrated, but not adjusted - like plain/thread plug/pin gauges, ring gauges, snap (aka 'Jo' blocks), slip, end/length and other similar 'fixed' gauging.