car paint meter principles

The car paint meter is equipped with probes of different frequencies and chip sizes, which can measure the surface coating thickness of different materials. Automatic error adjustment is carried out through functions such as probe to zero calibration and two-point calibration. At the same time, it uses reverse sound velocity measurement. , To improve measurement accuracy. Different measurement methods are used according to different materials to be measured. Among them, the two most commonly used measurement methods are magnetic induction measurement and eddy current measurement.

The magnetic induction thickness measurement method is mainly used to measure the thickness of the non-magnetic coating on the magnetic material. This measurement method has high accuracy and is usually used to measure magnetic materials such as steel, iron, and silver. When the probe of the paint film thickness gauge is in contact with the coating, the probe will form a closed magnetic circuit with the magnetic metal substrate, but the non-magnetic coating on the surface of the magnetic metal will obstruct the magnetic circuit, resulting in a change in magnetoresistance. The change of magnetoresistance can get the thickness of the surface covering layer.

The main character of the eddy current thickness measurement method is used to measure the thickness of the non-conductive coating on conductive materials. This measurement method is less accurate than the magnetic thickness measurement method. Eddy current thickness measurement can achieve non-destructive measurement, measuring the thickness of non-magnetic metal substrates such as aluminum, copper, stainless steel, etc. on non-conductive coatings. Non-conductive coatings include paint, plastic, rubber, powder, etc.
Ultrasonic thickness measurement method currently has a limited range of applications, and only a few foreign manufacturers use this type of paint film thickness gauge.
Ultrasonic thickness measurement is mainly used to measure the thickness of plating or coating. Although its measurement accuracy is not high, it can be applied to occasions where the above two methods cannot be achieved.
The electrolytic thickness measurement method is different from the above three measurement methods, because the electrolytic thickness measurement method needs to destroy the coating layer on the surface of metal and other materials, and its accuracy is not high, which may cause some problems and cannot achieve non-destructive testing.