7
Calibration and Adjustment
The
PosiTest PC
probe is factory calibrated and performs an
automatic self-check each time it calculates a measurement. For
most powder measurement applications, no further adjustment is
necessary. Simply
Zero
the gage (pg. 4) at the beginning of
each shift, then measure.
The
PosiTest PC’s
factory calibration accurately predicts cured
powder thickness for a wide range of powder coatings. However,
some powder formulations may require a
Calibration Adjustment
.
Begin by performing a
Verification of Accuracy
to determine if
there is a need for an adjustment. If the average of several
thickness results is outside the combined tolerances of the two
measuring instruments (
PosiTest PC
and dry film thickness
instrument) then two adjustment techniques are available to
correct the variance (see
Adjustment Techniques
).
Verification of Accuracy
Before first use on a new powder and periodically thereafter, an
accuracy check should be performed. This ensures the gage
measures properly by comparing predicted thickness values with
actual cured thickness values.
1.
Zero
the probe (pg. 4).
2.
Spray powder onto a flat, smooth metal sample.
3.
Measure the uncured powder with the
PosiTest PC
.
4.
Cure the powder.
5.
Measure cured thickness with a magnetic or eddy current
coating thickness gage such as the
PosiTest DFT
or
PosiTector 6000
.
6.
Compare results.
A successful verification requires that the average of a series of
measurements by both instruments be within their combined
tolerances. If not, adjust the
PosiTest PC
using one of the
methods described in
Adjustment Techniques
(pg 8).
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.com
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