Phascope Ideal for Thickness Measurement Tasks
Fischer Instrumentation has revealed how the Phascope PMP10 Duplex is being used by a car manufacturer to measure paint thickness and zinc thickness at the same time. Galvanised steel sheet is used with increasing popularity in the automotive industry for corrosion protection. The zinc coating is already applied by the sheet metal supplier either by galvanic deposition or in a zinc dip bath. If the zinc coating thickness was uniform, the coating thickness of the subsequently applied paint could be measured using a conventional magnetic induction coating thickness measuring instrument.
One would simply have to deduct a constant value from the actual reading. However, this uniformity of the zinc coating thickness is typically given within a batch on the supplied sheet that has still to be formed. When the body parts are formed, flowing or even scraping off the zinc coating may occur in the areas of severe bending radii, and this may vary its thickness by between 3 and 9um, and occasionally remove the coating altogether. Similar situations are encountered when repairing a body area that has coating defects due to sanding and subsequent repainting of the defective area.
In this case too, the zinc coating may be sanded away as well, leading to an apparent reduction in the paint thickness if the above-mentioned conventional paint coating thickness measurement system is used. This is not only problematic for the inspection of the finished painted body but also critical in the quality monitoring of a cataphoretic paint, because that thickness is typically only about 20um and a defect in the coating thickness measurement of 5 or 6um through a reduced zinc coating cannot be tolerated.
The Phascope PMP10 Duplex is ideally suited for measuring the paint thickness and the zinc thickness at the same time (and on the same spot). The repeatability precision of the zinc thickness measurement is as low as a few tens of nanometres, and that of the paint thickness measurement is below 0.5um. In order to reduce vehicle weight, the use of aluminium is becoming increasingly popular for non-safety-relevant components of the body. Therefore, the measuring instrument is also equipped with a conventional eddy current channel to measure the paint thickness on these parts according to a standard.
Without any action by the operator, who may not even know which parts are made of steel and which parts are made of aluminium, the instrument automatically selects the required measuring method - duplex or eddy current - immediately after the probe touches down and stores the paint thickness data in the same application in such a way that a simple evaluation of the paint thickness distribution is possible regardless of the type of sheet metal. The portable Phascope PMP10 Duplex is commonly used with a probe ESG 20, combining magnetic induction method and a phase-sensitive eddy current.
One would simply have to deduct a constant value from the actual reading. However, this uniformity of the zinc coating thickness is typically given within a batch on the supplied sheet that has still to be formed. When the body parts are formed, flowing or even scraping off the zinc coating may occur in the areas of severe bending radii, and this may vary its thickness by between 3 and 9um, and occasionally remove the coating altogether. Similar situations are encountered when repairing a body area that has coating defects due to sanding and subsequent repainting of the defective area.
In this case too, the zinc coating may be sanded away as well, leading to an apparent reduction in the paint thickness if the above-mentioned conventional paint coating thickness measurement system is used. This is not only problematic for the inspection of the finished painted body but also critical in the quality monitoring of a cataphoretic paint, because that thickness is typically only about 20um and a defect in the coating thickness measurement of 5 or 6um through a reduced zinc coating cannot be tolerated.
The Phascope PMP10 Duplex is ideally suited for measuring the paint thickness and the zinc thickness at the same time (and on the same spot). The repeatability precision of the zinc thickness measurement is as low as a few tens of nanometres, and that of the paint thickness measurement is below 0.5um. In order to reduce vehicle weight, the use of aluminium is becoming increasingly popular for non-safety-relevant components of the body. Therefore, the measuring instrument is also equipped with a conventional eddy current channel to measure the paint thickness on these parts according to a standard.
Without any action by the operator, who may not even know which parts are made of steel and which parts are made of aluminium, the instrument automatically selects the required measuring method - duplex or eddy current - immediately after the probe touches down and stores the paint thickness data in the same application in such a way that a simple evaluation of the paint thickness distribution is possible regardless of the type of sheet metal. The portable Phascope PMP10 Duplex is commonly used with a probe ESG 20, combining magnetic induction method and a phase-sensitive eddy current.
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