Abstract: The present invention stably supplies a side blow gas to a piercing site and prevents the adherence of spatter to a cutting nozzle. A hood, which is attached to a side blow gas nozzle, guides side blow gas jetted from a side blow gas nozzle to the piercing site and prevents spatter from adhering to the cutting nozzle as laser beam and assist gas are respectively radiated or jetted onto a cutting material through a communicating hole.

Abstract: In a piercing operation prior to the laser cutting of steel, etc., the development of a technology in which a piercing hole of the intended shape is obtained in a short time, even for a thick cut work. An oxygen gas coaxial to the laser beam applied towards the cut work and a low concentration gas with a low oxygen concentration and major components comprising nitrogen gas, air, or a mixture thereof discharged from an outer gas nozzle disposed so as to surround the outer side of the flow of this oxygen gas is supplied and disposed towards said cut work, and can realize shortening of the time, etc., of the piercing operation time by applying a laser beam to the cut work. In addition, a laser processing nozzle provided with an inner gas nozzle which discharges oxygen gas and an outer gas nozzle which discharges low concentration gas, and a laser cutting apparatus provided with this nozzle is provided.

Abstract: A development of a laser cutting method and a laser cutter in which the adverse effects such as self burning to the cutting surface can be prevented, when the material is cut at a high speed, has been desired. In order to achieve the object, the present invention provides a laser cutting method and a laser cutter in which a cutting laser beam 22 is applied to a material 25 to be cut at a cutting point 26, while ejecting gases 23 and 24 to the cutting point 26 or its surrounding area from a plurality of nozzle openings 30 and 31 arranged in a ring or in a line, wherein the oxygen concentrations of the gases 23 and 24 ejecting from at least one of the nozzle opening 30 and 31 are changed to adjust the oxygen concentration distribution in an area within several millimeters of the cutting point 26; thereby the cutting quality can be improved.

Abstract: The present invention stably supplies a side blow gas to a piercing site and prevents the adherence of spatter to a cutting nozzle. A hood, which is attached to a side blow gas nozzle, guides side blow gas jetted from a side blow gas nozzle to the piercing site and prevents spatter from adhering to the cutting nozzle as laser beam and assist gas are respectively radiated or jetted onto a cutting material through a communicating hole.