Everyone involved in measurement technology knows the somewhat flippant ? but very catchy ? statement: ?In the event that you measure a lot, you measure nothing!? What is meant by that is: It is possible to measure a lot. However the values are only useful if you can validate them. In everyday activity, for example, one may be surprised once the scales at home show a large deviation from those at the doctor?s or the bicycle speedometer deviates many a huge selection of metres from the GPS instrument. The saying also often alludes to our tendency to generate more and more data inside our modern world, without considering its evaluation. To be able to obtain valid data with which to keep working, it really is worthwhile for industrial measuring instruments to be calibrated regularly.
For the individual, the best accuracy is probably not important. In industrial applications, however, it really is precisely this that may make the key difference between rejects and the highest quality ? hence the calibration of the measuring instruments. It serves to match the measuring device with the national standard ? in a nutshell: to check if the values are correct.
เกจวัดแรงดัน to the national standard
The keyword here is thus the traceability to the national standard. Realizing that the respective measuring instrument measures the right value could be of great importance for most applications. For example, ISO 9000 requires that the deviations of the test equipment used ought to be monitored. Having an up-to-date calibration, passing the audit is no problem. This avoids the repetition of the audit, production downtime or even a recall ? and thus reduces stress, time and costs. The expenditure on the calibration has thus quickly covered itself. Everyone is happy.
Besides meeting the audit requirements, traceability can also be necessary for quality assurance, optimising resource utilisation and reducing energy consumption. Finally, the most convincing reason to have one?s own measuring devices checked relative to the current standard is the feeling of security: The measuring instruments will continue steadily to provide the correct values!
Certification in accordance with the German accreditation body
The illustration shows the way the four calibration sequences relative to DKD-R 3-3 differ.
The highest standard for this may be the calibration certificate of the German accreditation body (Deutsche Akkreditierungsstelle ? DAkkS). WIKA has offered certification for pressure, temperature and electrical measurands (DC current, DC voltage and DC resistance) for quite a while. Since the beginning of 2022, tecsis has been accredited relative to DIN EN ISO / IEC 17025 for the measurand force.
Just what a DAkkS-certified calibration of force measuring instruments means is shown by the exemplory case of high-end force transducers, which are used in calibration machines. In their case, the test sequence follows the EN ISO 376 standard. At the very least eight measuring stages are approached, with a complete of five preloads, two upward series and two up-down series. In เพรสเชอร์เกจ , the force transducers are each rotated by 120�, which results in three installation positions. With 65 measured values (eight stages), your time and effort is correspondingly high. The purchase price for such a calibration goes together with this.
Regarding industrial devices, the question arises as to whether such a procedure is worthwhile. Alternatively, the DKD-R 3-3 directive could be applied. It describes four test sequences that may be selected in line with the requirements. WIKA and tecsis likewise have DAkkS certification because of this.
An additional option for regular calibration is the non-standardised 3.1 inspection certificate.
Practical examples
An illustrative example of the usefulness of regular calibration may be the checking of hydraulic compression force transducers. These instruments gauge the clamping forces of industrial machines such as for example punches, pneumatic presses, sealing presses, spindle presses, tablet presses and toggle lever presses. Here, calibration provides a contribution to ensuring safe working conditions.
Another example may be the instrumentation for checking the contact forces of welding tongs. Ideally, they are monitored continuously by built-in tension/compression force transducers, however they may also be checked at set intervals utilizing a test set for measuring electrode forces (model FSK01). This ensures the quality of the welding points and reduces wear on the electrodes.
For the tension/compression force transducers mentioned, calibration can be worthwhile, should they be utilized for monitoring very precise production steps. When pressing in cellular phone displays, for example, both the measuring instruments and their calibration can quickly pay off: If an error in that process isn’t noticed immediately (for instance, if only the travel is controlled), several thousand euros in material value could be destroyed within minutes.
Adjustment before calibration can be useful
According to the instrument, application and regulation, it may be worthwhile with an adjustment carried out before calibration. In this manner, the user ensures that their measuring instrument achieves the corresponding accuracy during calibration. For the calibration itself, the user gets the option of choosing the sort and procedure, both for the own and for third-party products.
Note
On the WIKA website you will see further information on the average person calibration services as well as on WIKA force measuring instruments (offers are also available in the web shop). Assuming you have any questions, your contact will gladly assist you to.
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Calibration or adjustment ? Where?s the difference?