Abstract: To simplify and to shorten the cutting of a glass sheet (3) with the help of a cutting tool (11) and the removal of a coating applied on glass sheet (3) with the help of a grinding tool (12), the scratching of glass sheet (3) and the removal of the coating in strips lying on both sides of the scratch lines, running parallel to the latter, is performed in a single operation. In the device proposed for this purpose, cutting tool (11) and grinding tool (12) are mounted on a common support (8) movable on a beam (5) over a supporting surface (2) for glass sheet (3). Grinding tool (11) is fastened to an auxiliary support (17), which can be pivoted around axis (10) of cutting tool (11) oriented perpendicular to supporting surface (2). Grinding tool (12) and cutting tool (11) can be raised from glass sheet (3) independently of one another and mounted on the latter. Further, a suctioning of the dust accumulating during removal of the coating from glass sheet (3) is provided.

Abstract: The open end of the nozzle 42 is positioned close to and facing the surface of the metal base 20 on the side were the portion of the semiconductor ingot is to be cut off. An electromagnetic valve 46 is provided in the passage through which compressed air is supplied to the nozzle 42. The initial position of the blade 19 is detected by the detector 50U and the counter 52 measures the distance the blade 19 travels downward from the detected position and then the comparator 56 detects the point at which the measured value matches the value set on the numeric value setting device 54. The electromagnetic valve 46 is opened to emit compressed air from the nozzle 42 after this detection, until the detection of the lower limit position of the blade 19 by the detector 50D.