Coating Thickness Gauges with Different Measuring Principles

From:Linshang     Time:2019/12/13 13:53:22     Browse:
The application of coating thickness gauges with different design principles is not the same.The ultrasonic thickness measurement principle is suitable for coating measurement of non-metal substrates.The measurement principles of eddy current and magnetic methods are suitable for coating thickness measurement of metal substrates.

      Customers who buy our coating thickness gauge often ask whether the Linshang coating thickness gauge can measure the coating thickness on wood or plastic? Wood and plastics are non-metallic substrates. The coating thickness gauges for such non-metallic substrates usually use the principle of ultrasonic thickness measurement. In the following, we will briefly introduce the three measuring principles and applications of magnetic method, eddy current method and ultrasonic method.

    1.Ultrasonic thickness measurement principle

ultrasonic principle

     The ultrasonic thickness measurement principle mainly uses the ultrasonic pulses from the measuring hair to reach the material interface through the measured object and the pulses are reflected back to the probe. Then, the thickness of the measured material is determined by the accurate propagation time of the ultrasonic wave in the material. All kinds of materials that can make the ultrasonic wave propagate inside at a constant speed can use this thickness measurement principle.
     For example, DeFelsko PosiTector 200 coating thickness gauge is an ultrasonic coating thickness gauge. This coating thickness gauge is suitable for non-destructive measurement of dry film thickness on concrete and masonry substrates. It can be used for large projects, so there is no need to repair the coating after inspection, saving time for supervisors and contractors.
    The ultrasonic coating thickness gauge is suitable for masonry substrates including stone, brick, tile, cast concrete, precast concrete, concrete block, asbestos cement board, renderings and gypsum board. The stacked substrates are usually porous and have varying degrees of surface roughness. Although this porosity and roughness help improve adhesion, repeatable measurements of coating thickness add to the difficulty.

    2. Magnetic measurement principle

     The magnetic thickness measurement principle we are referring to here specifically refers to the principle of magnetic induction measurement rather than magnetic suction measurement. Specifically, it refers to the magnitude of the magnetic flux that enters the ferromagnetic substrate through the non-ferromagnetic coating. The principle of coating thickness measurement using magnetic induction can measure the thickness of non-magnetic coatings on magnetic collectives. For magnetic substrates, the permeability of the substrate must be above 500. If the coating is also magnetic, the difference between the permeability of the coating and the substrate must be sufficiently large.
     Linshang coating thickness gauge adopts the thickness measurement principle of magnetic method. Moreover, new technologies such as frequency stabilization and temperature compensation are also used in circuit design. Use magnetoresistance to modulate the measurement signal. Magnetic thickness gauges can be used to accurately measure paint, enamel, plastic and rubber on steel surfaces. It can also be used to measure electroplated coatings made of non-magnetic metals, as well as various anticorrosive coatings for chemical and petroleum industries.

   3.Eddy current thickness measurement principle

     The eddy current thickness measurement principle specifically means that high-frequency AC signals will generate an electromagnetic field in the side coil. When the side is close to the conductor, a vortex is generated on the substrate surface of the substrate. As the probe gets closer to the metal substrate, the larger the vortex, the larger the reflection impedance. When the probe is farther away from the metal substrate, the eddy current is smaller and the reflection impedance is smaller. Therefore, the size of the eddy current directly represents the distance between the probe and the conductive substrate and also indicates the coating thickness on the conductive substrate. This measuring principle is used to measure the coating thickness on non-magnetic metal substrates.
    The coating thickness gauge based on the eddy current measurement principle can measure all non-conductive coatings on non-magnetic metal substrates. Such as home appliances, aluminum alloy doors and windows, aluminum products paint surface, plastic coating and anodized film. The coating thickness gauge based on the eddy current measurement principle will use high frequency materials as the coil core. Compared with other coating thickness gauges, the coating thickness gauge based on the eddy current principle is mainly different in the probe signal frequency.

   4.Linshang coating thickness gauge 

     Compared with the products in the same industry, the Linshang coating thickness gauge is a better product. Linshang Technology has invented LS220 paint thickness gauge, LS220B paint thickness gauge with Bluetooth, LS220H coating thickness gauge, LS221 coating thickness gauge, LS223 coating thickness gauge + F3N3 probe, LS223 coating thickness gauge + F5N3 probe. These 6 coating thickness gauges use the measuring principle of both magnetic thickness measurement and eddy current thickness measurement. An instrument can measure the thickness of non-magnetic coatings on magnetic metal substrates as well as the thickness of non-conductive coatings on non-magnetic metal substrates. This instrument has high measurement accuracy, long use time which is small and convenient for using.

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