Coating thickness is a critical variable when it comes to process control, product quality, and cost control. The measuring film thickness is a routine process for coaters as it can have a big impact on quality and cost of work. There are many different types of instruments that can be used to determine this value and the proper gauge to use usually depends on the shape and type of the substrate, the thickness range of the coating, the cost of the gauge, and the criticality of a precise measurement. These factors are among the most important things you should pay attention to when selecting the right coating thickness meter to use for any type of project.
Understanding the equipment you are using as well as how efficient it is for the coating operation at hand is important to ensure the quality of the new coating being applied. Some commonly used measuring techniques and methodologies used for measuring the thickness of cured organic films include non-destructive methods like eddy current, magnetic gauges, ultrasonic pulse echo, and micrometer measurement. Destructive dry film methods are also used like gravimetric or mass measurement and cross-sectioning measurement. Methods for liquid and powder coatings are also used to measure film thicknesses before it is cured.ral 9005 powder coating
Magnetic film thickness gages are commonly used for non-destructive measurement of non-magnetic coating on ferrous substrates. Coatings on ferrous metals like iron and steel are typically measured this way. Magnetic gages use one of two operational principles, namely, magnetic pull-of or electromagnetic induction.
Eddy current techniques also promote non-destructive measurement. Instruments that use Eddy current often use a coil of fine wire that conducts high-frequency alternating current to set up an alternating magnetic field at the probe's surface. When the instrument is brought near the conductive surface, the magnetic field triggers eddy currents or an opposing magnetic field, which is then sensed by the exciting coil or by an adjacent coil. Gages that use Eddy current resemble and are operated like electromagnetic gages, although they are commonly used to measure coating thickness on non-ferrous metals.
Ultrasonic pulse-echo gages, on the other hand, are used to measure coating thickness on non-metal substrates like wood and plastic. Like the previous types of gages, ultrasonic instruments won't damage coating in the process of measurement. Micrometers are another type of non-destructive coating thickness meter that allow for the measurement of different coating and substrate combinations. However, they may not be sensitive enough to detect thin coatings.
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