Test Stability Study Of Coating Thickness Gauge

The common coating thickness measurement technology can be divided into loss detection and lossless detection according to whether the substrate to be measured remains intact after measurement.This paper adopts a scheme combining the two measurement principles of eddy current thickness measurement and electromagnetic induction thickness measurement in lossless testing.The thickness gauge designed based on this scheme can measure the coating thickness on the surface of magnetic and non-magnetic substrates respectively.The research content of the article mainly includes: based on the principle of electromagnetic field and Maxwell's equations theory,expounding the principle of eddy current thickness measurement and electromagnetic induction thickness measurement,analyzing the influence of measuring probe structure parameters and excitation signal on sensor performance;combining the finite element software COMSOL to construct the sensor Simulation and analysis of the impact on sensor performance when the sensor excitation signal and probe structure(coil inner diameter,outer diameter and thickness)change.The simulation results show that the greater the frequency of the excitation signal,the higher the measurement sensitivity of the sensor,but the smaller the measurement range;the larger the inner diameter and outer diameter of the probe coil and the smaller the thickness,the higher the sensitivity of the sensor;when the excitation voltage has a small amount of jitter,The measurement result is unstable.After theoretically determining the probe structure and excitation signal,combined with the production process,a high-sensitivity,high-range and stable thickness gauge probe that integrates eddy current and electromagnetic induction measurement is processed.On the basis of theoretical analysis,this paper designs a measuring instrument for measuring the thickness of non-magnetic non-conductor coating on the surface of magnetic and non-magnetic substrates based on STM32.It can work in an environment of-10??40?,and the measurement range is 0-1000?m.,The measurement error is controlled within 2%.The instrument mainly includes modules such as sensor signal acquisition,data processing,bottom driver and human-computer interaction.The test results show that the thickness gauge has high measurement accuracy,strong environmental adaptability,and convenient human-computer interaction.At the same time,it also verifies the correctness of adjusting the probe structure parameters and excitation signal to improve the performance of the sensor.