© PCE Instruments
6
•
Sample support
o
For heavy sample pieces: no support is required
o
For medium sized pieces: the sample must be placed on a flat, stable surface
with no shaking.
•
The minimal sample surface thickness must comply with the requirements of Table 3.
•
For hard surface layers, the depth of the layer must comply with the requirements of
Table 3.
•
Coupling:
o
Light samples must be tightly coupled with a strong support. The two coupling
surfaces must be flat and smooth, and the amount of coupling agent should
not be excessive. The test direction must be perpendicular to the coupling
plane.
o
If the sample is a large-area plate, long rod, or bent; even if the weight or
thickness are large, the sample piece may be deformed or unstable, this will
result in inaccurate test values. Therefore, the sample should be reinforced
or supported on the back side of the sample piece.
•
The sample surface should not exceed 30 Gauss.
8.2
Measurement process
Before measurement, the instrument can be tested with a random test block. The indication error
and repeatability should not exceed the requirements of table 1.
Repeatability
[µm]
1-point
calibration (µ)
±(3 %H +
0.7)
±(3 %H
+ 1)
±(3 %H
+ 10)
±(3 %H
+ 0.7)
±(3 %H
+ 1.5)
±(3 %H
+ 1)
2-point
calibration (m)
±(1 %H +
0.7)
±(1 %H
+ 1)
±(1 %H
+ 10)
±(1 %H
+ 0.7)
±(1 %H
+ 1.5)
-
Table 1
Note: the random test block must be measured with a calibrated device.
8.2.1
Measurement procedure
•
Insert the probe into the probe input on the device.
•
The probe must be placed into the test sample. The probe, sample and operator must
now remain perfectly stable and the probe should be as perfectly perpendicular to the
sample as possible.
•
If the resulting value exceeds the measurable amount, the device will need to be
calibrated separately with 5 test pieces.
•
The distance between any two indentations or the distance from the centre of any
indentation must comply with table 2.
Table 2
Distance between two
indentation centres
Indentation centre distance from the
edge of the sample
not less than
not less than
3mm
5mm
