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MATERIAL CALIBRATION
•
The surface should be finely ground. The dispersion of measured
hardness values will rise with greater roughness of the surface and
will lead to inexact calibrations.
•
The hardness of the sample should be as homogeneous as possible
over the total surface. Variability of the hardness effects the
measurement and leads to incorrect calibrations.
The hardness of the reference sample can be determined e.g. with a stationary
hardness tester. If such an instrument is not available, the manufacturer of the
device can assist you.
First the four calibration parameter must be set:
1. Select the material type for the calibration. If no material type is
selected, the hardness values determined with this material can
later be not converted to a hardness scale other than HV.
2. Afterwards the hardness scale in which the calibration should be
made, must be selected. This corresponds to the hardness scale
of the reference sample.
3. Enter the hardness of the reference sample.
4. Enter the number of measurements that should be made for this
calibration. Usually four to five measurements are sufficient. If
great dispersion is to be expected, e.g. for rough surfaces, the
number can be increased.
If necessary the calibration can now be interrupted by pressing ESC.
If the calibration should be continued, the cursor key right ► must be pressed.
Now, the measurements for calibration have to be taken. The alphaDUR mini
makes a beep at the end of each measurement. The probe should be lowered
evenly and steadily.
When the calibration is done, the standard deviation of the measurements will
be displayed (in units of the selected hardness scale and as percentage of the
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