Automated calibration of length change sensors (extensometers). Quality assurance per DIN ISO 9000 requires that measuring instruments must be checked at specific intervals depending on the frequency and type of test equipment used.

A length change sensor is such a measuring instrument. Length change sensors, also known as extensometers or strain sensors, are implemented in a wide variety of areas related to material testing, as well as in research and development. This involves measuring changes to the material structure or yielding of materials up to the nanometer range.



Calibrating an extensometer in series production

The entire measurement setup is calibrated against a laser interferometer as a reference to increase the accuracy of the calibrating device, especially for strain sensors with very small measured values (under ± 1 mm).

Computer-controlled extensometer calibration

Computer-driven calibration test bench, extremely high precision, with mounted high-temperature diametral extensometer.

Mechanical setup of the calibration test bench

Positional changes made to the ultra-precision measurement table simulates the diametral change of a specimen.

The high-temperature transverse strain sensor is deflected over the entire measurement range.