Questions and Answers on Influencing Factors of Coating Thickness Gauge
1. Why is the instrument sometimes inaccurate?
This is a relatively general question. Because there are various reasons for the inaccuracy of the instrument. For the coating thickness gauge alone, there are mainly the following reasons that cause inaccurate measurement.
(1) Interference from strong magnetic fields. We have done a simple experiment, when the instrument works near the electromagnetic field of about 10,000 V, the measurement will be seriously disturbed. If it is very close to the electromagnetic field, there may be a crash phenomenon.
(2) Human factor. This situation often happens to new users. The reason why the coating thickness gauge can measure to the micron level is that it can take the small change of magnetic flux and convert it into a digital signal. If the user is not familiar with the instrument during the measurement process, the probe may deviate from the body under test, causing the magnetic flux to change and cause wrong measurement. Therefore, it is recommended that users and friends first master the measurement method when using the instrument for the first time. The placement of the probe has a great influence on the measurement. During the measurement, the probe should be kept perpendicular to the surface of the sample. And the probe should not be placed for too long, so as not to cause the interference of the magnetic field of the matrix itself.
(3) An appropriate substrate was not selected during system calibration. The minimum plane of the substrate is 7mm, and the minimum thickness is 0.2mm. Measurements below this critical condition are unreliable.
(4) The influence of attached substances. The instrument is sensitive to adhering substances that prevent the probe from making intimate contact with the overlay surface. Therefore, the attached substances must be removed to ensure that the probe is in direct contact with the surface of the covering layer. When performing system calibration, the surface of the selected substrate must also be bare and smooth.
(5) The instrument breaks down. At this time, you can communicate with technicians or return to the factory for repair.
2. During the measurement process, why sometimes there are obvious deviations in the measurement data?
During the measurement process, due to the incorrect placement of the probe or the influence of external interference factors, the measurement data may be significantly larger. At this time, you can press and hold the CAL key to clear the data so as not to enter the data statistics.
3. How to calibrate the system?
The method and type of calibration are common problems for new users. System calibration, zero point calibration, and two-point calibration have actually been written in the manual, and users only need to read it carefully. It should be noted that when calibrating the iron base, it is necessary to measure several times to prevent wrong operation; the samples for system calibration should be carried out in order from small to large. If individual standard pieces are lost, you can find samples with similar values to replace them.
4. What is the reason for the interference when starting up sometimes?
After the instrument is turned on, the measurement status arrow appears on the screen of the instrument and the measurement cannot be performed again, which means that the instrument has been interfered. There are two main reasons:
(1) When starting up, the probe is too close to the iron base, which is disturbed by the magnetic field of the iron base.
(2) The probe is not inserted properly or the probe cable is damaged.
Coating and cladding measurement has become an important part of the quality inspection of the processing industry and surface engineering, and is an essential means for products to meet high quality standards. In order to make products internationalized, there are clear requirements and regulations on the measurement of coating thickness in my country's export commodities and foreign-related projects.
The measurement methods of coating thickness mainly include: wedge-cut coating measurement, optical section coating measurement, electrolytic coating measurement, thickness difference measurement method, weighing method coating measurement, x-ray fluorescence method coating measurement, β Coating measurement by ray backscattering method, coating measurement by capacitance method, thickness measurement by magnetic measurement method and eddy current measurement method, etc. Among these methods, the first five are destructive testing, the measurement methods are cumbersome and slow, and most of them are suitable for sampling inspection. With the increasing progress of science and technology, especially in recent years, the coating thickness gauge has taken a big step towards the direction of miniature, intelligent, multi-functional, high-precision and practical. The measurement resolution has reached 1 micron, and the accuracy can reach 1%, which has been greatly improved. The coating thickness gauge has wide application range, wide measuring range, easy operation and low price. It is the most widely used coating thickness gauge in industry and scientific research.
