The instrument adopts eddy current thickness measurement method
(NFe Probe):
Measure non-conductive coating on non-magnetic metals substrate
(such as paint coatings on enamel, plastic, rubber, copper,
aluminum, zinc, tin substrates).
The electromagnetic field is generated by using high-frequency
alternating current in the coil. When the probe contacts the cover,
an eddy current in the metal substrate is generated and fed back to
the coil in the probe, which is obtained by measuring the feedback
effect of the coating thickness.
Measuring Conditions
a) The characteristics of substrate
Standard methods for magnetic substrate of magnetic properties and
surface roughness should be similar to the magnetic properties and
surface roughness of specimens substrate.
For eddy current method, the standard substrate of electrical
properties should be similar to the electrical properties of
specimens substrate.
b) The thickness of substrate
Check whether the thickness of the substrate is lower than the
minimum thickness, if not, can use one of method in 3.3 to
calibrate.
c) Edge effect
Should not be in the specimen shape changing places, such as edges,
holes, and the place such as Angle measurement.
d) The curvature
Should not be in curved surface measurement of the specimens.
e) Measurement and measured times
Usually as a result of the instrument measurement result is not the
same each time, so we must in every area from several measurement
results.Coating thickness and surface rough degree of local
differences, require at any repeated measurements in a specific
area.
f) Surface cleanliness
Before measurement, should remove any attached on the surface of a
material, such as dust, grease and corrosion products, but do not
remove any covering material.
