Research On Applying Laser Scattering Characteristic Of Object To Measure Surface Microcosmic Profile Precision Of Steel Plate

The precision of the surface microcosmic profile of the cold-rolled plate has been considered the one of the most important controlling parameters of the machining process. It can affect the friction factor between the steel plate and mould. It also affects the oil storage condition between the steel plate and mould and then affects the figuration capability during the steel plate pressing. The quality of steel plate surface such as reflecting and bepainting also can be affected. With the development and appliance of the photoelectric technique, laser technique and computer, a new tool has been applied to the precision measuring of the surface microcosmic profile. The non-contact photoelectric measuring technology based on this new theoretical technique has become the important tool of the modern product quality measuring. The system of the precision measuring of the surface microcosmic profile of the cold-rolled plate was a multi-parameter,real time and online measuring system that can apply to non-contact photoelectric measuring technology.This article based on the Beckmann's light scattering theory designed the system of the precision measuring of the surface microcosmic profile of the steel plate. The article talked about the scattering characteristic of light on the medium surface and analyzed the basic analysis method, hypothesis condition and the application of the Beckmann's scalar integral theory, rayleigh -Rice's SPM theory, S-C-S vector integral theory and other scattering theories. It also founded the light scattering model and analyzed the ration relation between the light scattering and the roughness measuring and established the approximate expression of the roughness surface. So it can be applied to the precision measuring of the surface microcosmic profile of the cold-rolled plate. And then we founded the model of the profile arithmetic average error Ra and the model of correlation length T of the cold-rolled steel surface, so that we can establish the ration relation between the specular reflection and surface roughness. Based on it, we designed the subsystem to measure the surface roughness Ra and the peeks of per inch (PPI) .In the measuring subsystem of Ra, in order to get the Ra value of the measured surface, we must measure the light intensity of the incident light and the specular reflect light. Moreover it is the key of the measurement that the choice of the wavelength of the incident light and the incidence angle. Through the analysis and the experiment of spectrum relation of the wavelength of the incident laser light and the reflectivity of the steel surface, and through the research of the intensity of the specular reflected light of the incident lights which wavelength is 0.6328 μm and 3.39 μm, we considered the 3.39 μm wavelength He-Ne laser as the light source. At the same time, through the theoretical calculate and analyses of test result, the incident angle 75° can be considered as the best angle. Otherwise,...