Length measuring instruments, as test instruments, fall under the risk determination of ISO 9001. As a result of increasing safety requirements, the importance of calibration in connection with this is greater. In the past, a good-bad test was often sufficient – as it also was, for example, with tapered thread gauges. By determining the actual dimensions of the effective pitch diameter, more concrete findings can now be derived here.
Alongside measuring test equipment, reference gauges are also used in production on a daily basis. Calipers, dial gauges, thread gauges, lever gauges, testing pins and parallel gauge blocks are likewise used in the thousands. Frequently, this service is carried out by external service providers. For example, WIKA, with its calibration laboratories, performs these tests as a service. The necessity of calibration lies, not just with the standards that must be met, but also in the optimisation and assurance of processes.
Necessity of calibration for length measuring instruments
ISO 9001 puts more emphasis on the possibility of negative influences on the quality of products. A constructive risk assessment involves a regular calibration of the internal test equipment as a supervisory authority. ISO 9001 requires a regular calibration of those measuring instruments which are directly related to the product quality. A required calibration interval is not specified.
The frequency of the calibration is therefore determined by the respective company. The significant criteria are the frequency of use and their properties and condition. The test intervals can only be determined individually, since they are influenced by several factors: Are the test items used to measure dry or greased parts? Will the thread be “lightly hand-tightened” by the personnel? At WIKA, the internal cycle of a new gauge, for example, is one year. Depending on the results, the following cycle is then defined. In particular, in the calibration of thread gauges, a range of manual steps are still necessary.
In summary, calibration is necessary, in every case, to ensure the correct measuring results, as well as to reduce costs by minimising machine and plant downtime. Based on the safety requirements mentioned, regular calibration and monitoring of the test equipment – and thus length measuring instruments – is of central importance.
If you have any questions, please do not hesitate to contact our serviceteam on workdays from 7 am to 4 pm (Fri. until 3 pm) by telephone on +49 9372 132-5049. For more information about our calibration & service centre, visit the WIKA website.
See also our article
Calibration of tapered thread gauges