Scale Calibration
Calibrated Trust
It is common wisdom that any instrument, particularly a scale, shall be calibrated before its first use. But is this sufficient? Shall I recalibrate my scale? How frequently? How? And Why?
If you are working in a regulated industry, you may have asked yourself these questions a thousand times. You may have heard some of the usual answers. But do you really believe what you heard? Here is more information for a conscious user.
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Calibration Benefits
When leaving the factory, a scale has been verified and adjusted for immediate use in an optimal environment. However, it is impossible to anticipate the conditions in which the scale will operate. Think of a working environment with large temperature changes, wind draft, vibration from rotating equipment, etc. An initial calibration will document the effective performance of a scale within its effective operating environment. At that time a calibration certificate is issued. Sometimes, a Minimum Weight certificate is issued as well. This certificate will document for which weighing range (from minimum to maximum) the scale will deliver results in the accuracy corresponding to the tolerance required by your process and taking into account all of the process risks. The calibration certificate and the Minimum Weight Certificate are two important quality documents that will protect you from rejected lots, customer complaints, or failed ISO audits.
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Recalibration and Verification
During operation, scales will be exposed to dirt, rough operators, and all sorts of disturbances that will affect its performance over time. So how will you know today that your production will meet all your quality standards? For this purpose, you will need to perform a series of simple routine tests that will confirm that the scale you are going to use will effectively perform to the level expected.
However, depending on the level of tolerance and the risk of your process, you will need to recalibrate your scale on a regular basis. A trained technician will then verify that the scale fulfills its factory performance and proceed to make any adjustments on an as needed basis.
A combination of simple routine testing and regular recalibration will ensure that your daily production fulfills all your quality requirements.
