|One aspect of materials testing machines
calibration which is frequently overlooked for non-metallic
materials testing, is the verification of the crosshead displacement
readout when either extension or modulus readings are required.
We are one of only a handful of UKAS Accredited Calibration
Laboratories that are accredited for crosshead displacement
alongside their accreditation for force calibrations.
Testing Calibration Services holds UKAS Accreditation for
the calibration of crosshead displacement to BS EN ISO 5893.
Crosshead displacement is used as a measure of sample extension
when constant cross-sectional area samples are tested and
there is negligible movement of sample in the grips as the
force is increased. This method can only be used on the so-called
"hard" materials testing machines where there is
little movement of the force sensor during the application
We are also able to calibrate the rate at which the crosshead
moves in mm/min. Many test methods state that the set test
speed should be within certain limits, as well as being a
requirement of BS EN ISO 5893. Calibration of the test speeds
that you use will show whether the test method is being conformed
to. This is especially important where test results are speed-dependent.