SU1585674A1 - Method of checking roughness of surface - Google Patents

Abstract

The invention relates to a measurement technique and can be used to control the roughness of sound-conducting materials. The purpose of the invention is to improve accuracy by reducing interference. Surface acoustic waves are excited on the test surface. Measured in relative units of their attenuation coefficient, it is possible to judge the surface roughness. The attenuation coefficient is determined by the optical method, emitting coherent beams at two points on the surface at an acute angle and registering the corresponding intensity maxima of the reflected diffraction beams. By their relation, the attenuation is judged and then by the calibration curve the attenuation of acoustic waves — the roughness determines the desired value. 2 Il.

Description

(21) 4361568 / 25-28

(22) 01/11/88

(46) 08/15/90. Bksh. No. 30

(71) Komsomolsk-on-Amur Polytechnic Institute

(72) V.F. Tsalko and E.V.Lanovenko (53) 620.179.16 (088.8)

(56) Patent of France No. 2531776, cl. G 01 B 11/30, 1984.

454) METHOD FOR CONTROL OF SURFACE ROUGHNESS

(57) The invention relates to a measurement technique and can be used to control the roughness of sound-conducting materials. The purpose of the invention is to improve accuracy by reducing interference. Surface acoustic waves are excited on the test surface. Measured in relative units of their attenuation coefficient, it is possible to judge the surface roughness. The attenuation coefficient is determined by the optical method of the radiation at two points on the surface at an acute angle of coherent beams and recorded the corresponding intensity maxima of the reflected diffraction beams. By their relation, the attenuation is judged and then by the calibrated attenuation of acoustic waves — the roughness determines the desired value. 2 Il.

The invention relates to mechanical engineering, in particular, to methods for controlling the quality of the polished surface of sound-conducting materials.

The purpose of the invention is to improve accuracy by reducing interference.

FIG. Figure 1 shows an installation with a laser probe on which the proposed method is implemented.

Position 1 marked controlled surface; 2 - a translucent mirror; 3 - lens; 4 - laser; 5 laser radiation intensity recorder; 6 aperture; 7 - lens; 8 - optical filter; 9 - lens; 10 - photomultiplier tube; 11 - broadband amplifier, 12 - intensity recording device

reflected radiation; 13 - light guide.

FIG. Figure 2 shows the calibration curve for the dependence of the coefficient of surface acoustic waves (SAS) of attenuation on the magnitude of the roughness to the length of the SAS.

The method is carried out in the following manner.

On the surface studied wake surfactant, such as a laser. Then, the attenuation of the surfactant depending on the roughness is measured. To do this, a coherent beam of radiation is directed at two different points on the surface at the same acute angle. The roughness and surfactant act upon reflection of the beams as a diffraction grating, and the intensity of the diffracted light

sd

CX)

ate

O5

4; ib

is proportional to the intensity of the sound wave, which is confirmed by the formula:

I sinxfL

  l / t

 2G

de

ImCy.

0 - M 36

light emission intensity at tU-M diffraction maximum;

the intensity of the main specular reflected beam; ,

- the length of the interaction of light radiation with a surfactant (in this case it is the diameter of the light beam); wavelength;

a parameter characterizing the acousto-optic qualities of the material (the value is constant);

- intensity of the sound waveRegister the intensities of the corresponding maxima, diffraction beams, the ratio of which characterizes. In arbitrary units of attenuation K surfactant, O roughness is judged by

0

five

0

five

 the dependences of the zatzghani K on the ratio of roughness to the length of the surfactant using the plot curve in FIG. 2

Claims (1)

Formulaisableness The method of controlling the surface roughness, which means that at one point of the surface, at a sharp angle, a coherent beam of radiation is directed and recorded the intensity of the reflected diffraction beam, taking into account which roughness is judged, characterized in that, in order to improve accuracy, the surface is excited acoustic waves, at the same angle to another point of the surface, direct a coherent radiation beam, record the corresponding intensity maxima of the reflected diffraction diffraction signals, and about Howat judged depending on the ratio of the intensity maxima of the reflected beams .from ratio of roughness to the length of the surface acoustic wave. ig. one 0.1 0.2 /7.3 OL 0.5 0.6 0.7 0.8 0.8 0.9 1.0 Phie. g to /, fO