Tips for changing the parameters of coating thickness gauge heads
The coating thickness gauge has become an important process for quality inspection of finished products in many industries, and is a necessary means for products to meet high-quality standards. The suction force between the permanent magnet (probe) and the magnetizing steel is proportional to the distance between the two, which is the thickness of the coating. Using this principle to make a thickness gauge, as long as the difference in permeability between the coating and the substrate is large enough, it can be measured. Given that most industrial products are formed by stamping structural steel and hot-rolled and cold-rolled steel plates, they are widely used.
The basic structure of the coating thickness gauge consists of magnetic steel, relay spring, ruler, and self stopping mechanism. After the magnetic steel is attracted to the measured object, the measuring spring is gradually stretched and the tension gradually increases. When the pulling force is just greater than the suction force, the size of the pulling force can be recorded at the moment when the magnetic steel detaches to obtain the coating thickness. The new product can automatically complete this recording process. This instrument is characterized by easy operation, durability, no need for power supply, no need for calibration before measurement, and low price. It is very suitable for on-site quality control in the workshop.
The coating thickness gauge is an effective means of non-destructive measurement of the thickness of non-conductive coatings on non-magnetic metal substrates listed above. The development and application practice of modern engineering materials have shown that various non-ferrous metal materials such as aluminum, copper, zinc, and their alloy materials are widely used in industries such as aviation, building materials, metallurgy, light industry, machinery, instruments, and chemical engineering, often requiring anti-corrosion protection with surface coatings such as oxide film, paint, spray molding, and rubber to extend their service life.
When the coating thickness gauge head comes into contact with the tested sample, the high-frequency electromagnetic field generated by the gauge head device causes eddy currents in the metal conductor placed below the gauge head. Its amplitude and phase are functions of the non-conductive coating thickness between the conductor and the gauge head. That is, the alternating electromagnetic field generated by the gauge will change the gauge head parameters, and the magnitude of the gauge head parameter variable depends on the thickness of the coating layer. By measuring the size of the measurement head parameter variable and converting this electrical signal, the thickness value of the measured coating layer can be obtained.
Once the coating thickness gauge is calibrated, the parameters will be saved and the calibration process does not need to be repeated. It is recommended to use the same calibration substrate/foil as the previous calibration instrument after prolonged operation or when the instrument is not in use for a period of time. This process is achieved by zeroing the instrument on an uncoated test piece, and the coating thickness will be measured on this test piece.
