| 摘要 |
The subject of the invention is a method and a device for locating surface evenness defects in a metal sheet by illuminating the metal sheet 1 placed flat on a flat support 2 with glancing light. According to the invention, there is projected onto the metal sheet 1 a laser beam 3 with constant thickness e, capable of covering a plane P which is inclined with respect to the flat support 2 and respectively cutting the latter along a rectilinear reference line 21 and the metal sheet 1 along a wavy line 42, and above the wavy line 42, parallel to the reference line 21, a reader device 5 is moved, which allows measurement at a plurality of reading positions distributed along the wavy line 42 of the transverse separation with respect to the theoretical line of the centre O of the light spot 4 projected by the beam 3 onto the metal sheet 1, and of the ratio of the length d in horizontal projection of this spot to the thickness e of the beam; by means of a central computation unit 63 associated with the reading device 5, the elevation h of the metal sheet 1 and the angle of inclination B of its plane which is tangent to the support plane are then determined from these two measurements, at each reading point O. The invention applies especially to producing metal sheets for calibrating means for measuring surface evenness during passage. <IMAGE>
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