| 摘要 |
1,235,653. Cutting by burning; cutting wood by lasers. NATIONAL RESEARCH DEVELOPMENT CORP. 5 Jan., 1970 [10 Jan., 1969], No. 1578/69. Headings B4B and B5L. [Also in Divisions B3 and H1] In a laser cutting operation, the workpiece 32, Fig. 1, e.g. cloth, leather, paper, plastics, timber, is positioned between a laser beam 26 and a suction chamber 36 for extracting the fumes. In one embodiment, Fig. 1, the workpiece is supported on a grid 34 of the chamber 36 which is connected via a valve 38 to a reservoir 40, filter 42, suction pump 44 and motor 45. The laser beam is moved over the workpiece by moving a mirror 28 and lens 30. The laser beam energy is absorbed by a firebrick layer 46. In another embodiment, Fig. 4, a drum 86 having a cylindrical grid surface 85, is divided into segments by walls 88 having ceramic coatings 89, each segment having a firebrick layer 46. As the drum is rotated relative to a stationary shaft 90, each segment is connected in turn to a suction chamber 92 in the shaft 90 and the workpiece 32b is cut by the laser beam 26a which may be movable. A chamber 94 in the shaft 90 is connected to atmosphere so that each segment is filled with air after it has moved out of the working position. In a further embodiment (Fig. 5, not shown), a water-cooling coil (100) is positioned around the suction chamber. A jet of water may be directed on to the workpiece during cutting. |
