Abstract: A method and an apparatus for sharpening a cutting blade of a numerically controlled cutting apparatus which includes a conveyor for supporting material to be cut and a cutting head assembly mounted on a carriage disposed above a cutting surface of the conveyor. The cutting head assembly includes a cutting blade, a mechanism for rotating the cutting blade about an axis perpendicular to the cutting surface, a mechanism for raising and lowering the cutting blade and a pair of grinding wheels for sharpening the cutting blade. The rotating mechanism rotates the cutting blade from a first angular position at which cutting is performed to a second angular position at which the pair of grinding wheels sharpen the cutting blade.

Abstract: In a flat table drawing plotter, an image is drawn on the portion of a continuous work piece, e.g., a sheet of paper, located on a drawing table. Upon completion of the drawing of the image, a trace line is drawn at the rear end location of the image. The drawing carriage, having an optical detector means mounted thereon, is moved to the forward end of the table. The work piece is advanced with the optical detector means in continuous contact therewith. The advance of the work piece is stopped when the optical detector means detects the trace line. Then, the drawing carriage is slowly moved until the optical detector means again detects the trace line thereby identifying where the prior drawing of the image was completed. Drawing of the image is then recommenced.