Basics of Construction: Learn More about Coating Thickness Meter

Coating thickness meters or gauges determine the thickness of paint and corrosion layers in surfaces. These devices use principles of measurement based on magnetic induction or by analysing eddy current values. Most gauges are designed to test coating thickness on various types of surfaces, as long as they are made from metallic materials like metal, iron, and non ferrous metal alloys.

Coating thickness gauges are designed for performing quality control tests for anodising or galvanising processes. It is an essential tool for measuring and determining coating conditions in the automotive sector. While most coating meters are made for metallic surfaces, there are also wall thickness gauges that are specifically designed to determine the hardness of metal, glass, and even plastic walls and windows. They are particularly useful in identifying wall thickness for different types of pressure pipes like steam pipes.

Coating thickness meters are advantageous because they provide a non-destructive method of investigation for determining the thickness of materials. Today, they are regularly utilised in different areas of industrial measurements. These tools allow measurement without the need for accessing either side of a test piece. Thus, surfaces stay intact. Many of these tools use ultrasonic technology, which allows for testing different types of materials without the need for damaging or collecting samples from the testing surface.

A simple ultrasonic thickness meter can determine the thickness by gauging the amount of time that it takes for sound to traverse from its transducer through the material and then back to the end of a part. It then measures the time that the reflection takes to return to the transducer. Equipped with intelligent technology, a thickness gauge can automatically calculate the data retrieved based on the speed of sound measured through the tested sample.

Two basic types of transducers are used for ultrasonic thickness measurement. These are EMAT and piezoelectric sensors. Both of these sensors emit sound waves into a tested material when excited or triggered. They typically used predetermined frequencies, although certain meters also allow for manual frequency tuning so they can be used to measure and inspect more types of materials. The standard frequency used by most ultrasonic thickness gauges is 5 MHz.

Some coating thickness meters require some form of a gel, paste or liquid couplant to eliminate gap between the test piece and the transducer. Gaps may cause inaccurate readings of thickness. A popular couplant used with coating thickness gauges is propylene glycol, although many other substances can be substituted.