Flexible Thickness Measurement

Many shops that coat a variety of substrate metals are faced with the problem of how to measure coating thickness on, for example, both aluminum and steel parts. Different coating materials and thicknesses can also impact coating thickness measurement accuracy and repeatability.

Addressing these issues is a new coating thickness measurement instrument that is said to allow accurate measurement of a wide range of coating thicknesses and types on both ferrous and nonferrous substrates.

According to developer Fischer Technology Inc. (Windsor, CT), the DualScope FMP100 combines the flexibility and capabilities of a PC-based lab instrument with the ease of use of a portable unit. The instrument uses a new generation of probes that Fischer says enable accurate measurement of coatings over a wider range of thicknesses that is wider than normal.

The instrument combines two physical measurement methods that conform to many thickness measurement standards and practices. For nonmagnetic coating materials such as zinc, chromium, copper or tin plate, or for paint or enamel on ferrous substrates, the FMP100 uses magnetic induction measuring according to ASTM B 499 and ISO 2178. The device uses eddy current testing according to ASTM B 244 and ISO 2360 for electrically nonconductive coatings on nonferrous substrates. It can also perform measurements according to ASTM D 7091-05 for dry film thickness measurement of nonmagnetic coatings on ferrous metals and for measurement of nonmagnetic, nonconductive coatings on nonferrous substrates. Fischer says instrument operation is straightfoward and the same for any of the various measurement methods.

Measurement can be accomplished using a probe dedicated to either the eddy current or magnetic induction methods or a dual probe that can handle either technnique. According to Fischer, the high precision of the probes enables a significantly increased measurement range that allows accurate measurement of both very thin and thick coatings.

The unit features a color liquid crystal display with a touch-screen user interface that is said to significantly simplify setup, measurement and data evaluation. Its touch screen can be operated using either a stylus or fingers. Other control elements such as soft keys, menu bars and a screen keyboard provide support.

Storage for all relevant measurement data, plus information n the configuration of a measurement application, is provided in a central file. Stored data includes material properties and the size and shape of the specimen, plus measurement, display and evaluation settings. Configurable dialogues can assist the operator and help error-proof a variety of thickness measurement tasks.

Users can view measurement data statistics including characteristic statistical values such as mean, standard deviation and confidence interval at the push of a button. Data can also be displayed graphically. Sum frequency diagrams and histrograms, for example, provide easily seen indications of potential systemic influences in measurement series. Graphical data presentation also enables rapid evaluation of production processes and differences between various shipment during incoming inspection, Fischer says.