| Research Abstract |
The free surface qualities of the material change accompanied with a plastic deformation level. It has been investigated for a long time that the surface roughness of the material increases with an increasing strain. The control of the surface roughness of product before pressing the thin plate and plating the cold rolled sheet is a serous problem. Therefore, it is necessary that the surface roughness is quantitatively measured with high accuracy. Generally, the methods for measurement of the surface roughness are to measure the profile of the surface by using the profile meter and to measure the brightness by using the reflection meter. In the former method, it is difficult to measure the two dimensional surface roughness in operation, and in the latter method, it is possible to measure the mean surface roughness nondestructively, but the values can not be measured with accuracy. Consequently, the two dimensional surface roughness can not be measured in operation with high accuracy by
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these methods. A new method for measurement of the surface roughness has been developed by means of a laser beam by the authors. If the laser beam with a high coherency is thrown on the rough surface of metals, the laser beam is diffracted by the surface structure of the metal and the characteristic intensity distribution is observed. The observed distribution is obtained by Fourier transform of the distribution of the beam wave. Since the surface profile of the metal is connected with the distribution of the beam wave, the intensity distribution includes the qualities of the surface profile. Therefore, the surface profile can be examined by measuring the intensity distribution. It is possible to measure the surface roughness nondestructively without touching the material by this method. Since this method can be used in operation, the application of this method to the control of the product surface expected. In this paper, a inline apparatus for measurement of surface quality is developed newly. Less
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