Calibration
The importance that measurement has in all market sectors is such that we all use and depend upon it every day in even the most mundane aspects of life; from setting your wristwatch against the radio or telephone time signal, checking the weather forecast or filling your vehicle with fuel. For success, all of these depend upon correct calibration services and traceability to national standards.
Over time components and equipment are subjected to changes in temperature or may endure mechanical stress, causing critical performance to slowly degrade. This is called drift. When this occurs your test results become inaccurate/unreliable and both design and production quality can suffer. Although drift cannot be eliminated, it can be identified, and taken in to account through the process of calibration.
Wikipedia, definition of Calibration?
Definition of Calibration
Calibration is the determination of the accuracy of an instrument, usually by measurement of its variation from a standard, to ascertain necessary correction factors.
Calibration can also involve the act of adjusting equipment so that it performs in accordance with an established standard or specification.
The process of Calibration establishes, under specified conditions, the relationship between the values indicated by the measuring system, and the corresponding values of a quantity realised by a reference standard or working standard within specified accuracy and precision. Measurements are based upon International Standards which are traceable; meaning all readings for each calibration is logged and therefore traceable right down to the equipment used for the instrument calibration.
For example, a thermometer could be calibrated so that it showed the temperature in Celsius at the correct point. Calibrated equipment provides confidence that your products/services meet their specifications.
Put simply, having your equipment calibrated:
- increases production yields
- optimises resources
- assures consistency
- ensures measurements (and perhaps products) are compatible with those made elsewhere
- ensures compliance with International Quality Systems
Examples of problems that have occurred from not calibrating equipment
A major manufacturer of premium golf balls didn't have their weighing scales checked because they were used for shipping purposes only. They shipped out large containers of balls based on a total weight. After a program of periodic calibration was finally implemented, they discovered that each bin contained 300 more balls than had been stated which was equivalent to a £500 loss per bin.
A manufacturing process used an oven with a calibrated temperature controller. After three months the controller was found to be inaccurate meaning that the actual temperature was substantially higher than specified. The quality and reliability of products made during the whole period were now in question and a costly product recall seemed necessary. Although it finally transpired that the error didn't adversely affect manufactured product, it took a month's work to prove it.
There are many more cases like these but the point is that it's not worth leaving your equipment to potentially be fine by not having it calibrated!