10 Operator‘s Manual for instrument types MP0R
Influencing Variables Taken into Consideration
4 Influencing Variables Taken into Consider-
ation
Main variables influencing the coating thickness measurement:
• Physical properties of the specimen substrate material such as the elec-
trical conductivity or the permeability.
• The geometric design of the specimen such as the thickness of the sub-
strate material or a cylindrical shape.
• The position of the measurement spot on the specimen: distance to the
edge, hole, offset or step.
• Surface roughness.
For correct measurements of the coating thickness, the instrument and the
probe, together referred to as the measurement system, must “become
familiar” with the specimen (part). This is done using a calibration. The
influencing parameters are captured using a reference part and can then
be compensated in future measurements. The calibration is preformed for
the respective open Application.
4.1 Kinds of calibration
In calibration, we distinguish between normalization and corrective calibra-
tion.
Normalization
The Normalization is the simplest kind of calibration and is used for
adapting the measurement system to a reference point. These are the
base materials (magnetizable or non-magnetizable and electrically
conducting depending on the used test method). Measurements are made
on a reference part that corresponds in material and shape to the actual
part to be measured. It consists only of the base material, i.e., without the
coating material to be measured.
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