Coating thickness gaugeThe core principle is based on the variation of physical fields (magnetic fields or eddy currents), which indirectly converts the coating thickness.

　　Coating thickness gaugeIt is mainly divided into two categories:

Magnetic thickness measurement method

Applicable substrate: ferromagnetic metals (such as steel, iron, nickel, etc.).

Principle: The probe is equipped with a magnet or electromagnetic coil, which generates a stable magnetic field when powered on. When the probe contacts the surface of the coating, non-magnetic coatings (such as paint, rubber) will "block" the magnetic field, causing the magnetic path to become longer, the magnetic flux to decrease, and the magnetic resistance to increase. Sensors capture magnetic field changes, convert them into electrical signals, and then convert them into coating thickness through calibration curves.

Characteristics: High measurement accuracy, suitable for thin coating detection, and is one of the commonly used methods in industry.

Eddy current thickness measurement method

Applicable substrate: Non ferromagnetic conductive metals (such as aluminum, copper, magnesium, etc.).

Principle: The probe is equipped with a high-frequency oscillating coil, which generates a high-frequency alternating magnetic field when powered on. When the probe approaches the substrate, the magnetic field induces eddy currents on the surface of the substrate. Coating (non-conductive) will "weaken" the magnetic field strength, resulting in a decrease in eddy current intensity, which in turn affects the impedance of the probe coil. The instrument detects impedance changes and converts them into coating thickness.

Features: Suitable for non-ferrous metal substrates, but with slightly lower accuracy than magnetic methods.