Patent ID: 6224459
Filing Date: 2001-05-01
Classification: B23Q,B24B,H01L

Abstract:
A machine for edge grinding circular workpieces, comprising workpiece holding means for attachment to the face of a workpiece to move the latter from one position to another, robotic means controlling the position of the workpiece holding means and adapted to move in at least two orthogonal directions, both of which are parallel to the plane of the workpiece when it occupies an optical inspection station, means for rotating the workpiece in the inspection station and in a machining station, inspection means for determining the position of the geometric centre of the workpiece as it is rotated in the first station, and computing means for calculating from data delivered by the inspection means any shifts required along the orthogonal directions of movement of the robotic means, to move the geometric centre of the workpiece to a second desired position whose coordinates are known, the optical inspection means comprising a CCD camera having its optical axis parallel to the axis of the workpiece and which forms an optical image of the edge of the workpiece of the CCD chip, and means for illuminating the edge region of the disc for viewing by the camera in silhouette, wherein the CCD array contains a large umber of addressable pixels in a rectangular array.