Abstract: Hafnium carbide powder for plasma electrodes is represented by a chemical formula HfCx (where x=0.5 to 1.0). The content of carbon particles contained as impurities in the hafnium carbide powder is less than or equal to 0.03% by mass. The hafnium carbide powder preferably has an average particle size of 0.5 to 2 ?m. To produce the hafnium carbide powder, a pellet made from mixed powder of hafnium oxide and carbon is first placed in a second crucible made of silicon carbide. Then, the hafnium carbide powder is formed by heating the second crucible at 1800 to 2000° C. with the second crucible arranged in a first crucible made of carbon.

Abstract: A laser cutting device includes a control unit which sets a steady oxygen concentration, a moving speed of a laser nozzle and laser beam steady control conditions based on a material and a plate thickness of the workpiece, decreases the moving speed of the laser nozzle to a first setting speed when the laser nozzle arrives a first setting position in front of an end point of a cutting trajectory, and decreases a relative moving speed of the laser nozzle to a second setting speed by varying the oxygen concentration of the cutting gas and the control condition of the laser beam when the laser nozzle arrives at a second setting position.

Abstract: A laser cutting device includes a control unit which sets a steady oxygen concentration, a moving speed of a laser nozzle and laser beam steady control conditions based on a material and a plate thickness of the workpiece, decreases the moving speed of the laser nozzle to a first setting speed when the laser nozzle arrives a first setting position in front of an end point of a cutting trajectory, and decreases a relative moving speed of the laser nozzle to a second setting speed by varying the oxygen concentration of the cutting gas and the control condition of the laser beam when the laser nozzle arrives at a second setting position.

Abstract: A processing apparatus is provided in which a laser beam L2 is irradiated onto a processing portion of a workpiece W, and at the same time as the laser irradiation, an assist gas G is injected toward the processing portion from a nozzle 3 arranged concentric to the laser beam L2 so that the processing portion is covered with the assist gas G, thereby processing a piercing hole H on the processing portion. The apparatus includes control means 10 for processing a piercing hole H while moving the nozzle 3 within the range of 5 mm from a processing start point after the irradiation of the laser beam L2 is started.

Abstract: A processing apparatus is provided in which a laser beam L2 is irradiated onto a processing portion of a workpiece W, and at the same time as the laser irradiation, an assist gas G is injected toward the processing portion from a nozzle 3 arranged concentric to the laser beam L2 so that the processing portion is covered with the assist gas G, thereby processing a piercing hole H on the processing portion. The apparatus includes control means 10 for processing a piercing hole H while moving the nozzle 3 within the range of 5 mm from a processing start point after the irradiation of the laser beam L2 is started.