METHOD FOR FRACTAL MONITORING OF SURFACE ROUGHNESS Russian patent published in 2019 - IPC G01B11/30 G01N21/88 

FIELD: machine building.

SUBSTANCE: invention relates to means of controlling microroughnesses of surfaces obtained from mechanical engineering operations on a rough surface, for example, the surface of a gas turbine engine blade at final stages of treatment. Disclosed method of fractal control of surface roughness consists in that the analysed surface is cleaned by plasma-chemical etching in an inert gas medium under conditions, not allowing the material of the analysed surface to be sprayed, immediately after cleaning, a drop of liquid of known viscosity and fixed volume is applied onto the analysed surface, then the time of spreading of a drop of liquid of known viscosity is recorded using a high-speed digital video camera and fixed volume on analysed surface and roughness of analysed surface is determined. For this purpose, beforehand by means of high-speed digital video camera moment of flowing out of liquid drop of known viscosity and fixed volume is registered, after which perimeter and area of spread drop of known viscosity and fixed volume is determined and high-speed digital video camera is removed, then liquid droplets of known viscosity and fixed volume spread on the analysed surface are coated with a liquid of lower viscosity in form of a second drop, wherein liquid of second drop must be soluble in first drop liquid, after which high-speed digital video camera is put into initial position, by means of which moment of flow spreading of the second drop of liquid dissolved in the first drop of liquid of known viscosity and fixed volume is registered. Further, perimeter and area of spread droplets formed as a result of merging of two drops of liquids of different viscosity are determined. Obtained data are used to determine fractal dimension D of analysed surface D = 2⋅log_a(G_length1/G_length2), where a = (G_area1/ G_area2), where G_length1 is perimeter of spread liquid drop of known viscosity and fixed volume; G_length2 is the permeate of the spread droplet formed by merging two drops of liquids of different viscosity; G_area1 is area of spread liquid drop of known viscosity and fixed volume; G_area2 is the area of spread droplets formed as a result of merging two drops of liquids of different viscosity.

EFFECT: technical result is higher accuracy of monitoring surface roughness level and expanded series of materials of analysed surface.

1 cl, 1 dwg