engleski

Significance of Preload in the Testing Machine Calibration Procedure

Preload plays an important role in the calibration procedure of a testing machine and represents an inevitable part of the calibration process. Preload affects the calibration results in the form of relative errors of the force-measuring system, which also indirectly influences the class of the measuring range. By applying one or several preloads, the values of characteristic relative errors of accuracy, repeatability and reversibility, which represent the classification criteria for determining the class, are significantly changed. A greater number of preloads make the error of accuracy bigger whereas the error of repeatability and the error of reversibility in particular are reduced in the absolute amount. Furthermore, preload also affects the residual force which remains on the force transducer after removing the load. Only one preload already minimizes this residue and thus allows valid testing. Therefore, the preload in checking the testing machine represents an important precondition of calibration with the aim of obtaining the correct information about the accuracy of the tested measurement instrument.

calibration; testing machine; preload; force

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