Abstract: A laser processing machine 100 includes: a laser processing unit 1 configured to process a workpiece W by using a laser beam L; an imaging device configured to image the workpiece W irradiated with the laser beam L; and a control device configured to control the laser processing unit 1 in accordance with a processing condition 51c for processing the workpiece W. The control device controls operation of the laser processing unit 1 such that size OIS of an optical image OI and a peak value PV of light intensity LI of the optical image OI observed from image information obtained by imaging the workpiece W with the imaging device approach preset reference values 60.

Abstract: A laser cutting nozzle includes an inner nozzle and an outer nozzle. The inner nozzle exhibits a tube shape having a through hole on an axis and having a diameter decreasing on a first end portion side and includes a notch extending in the axis direction along an outer peripheral surface on a second end portion side. The outer nozzle is fitted to the outer peripheral surface of the inner nozzle and includes a vent passage including the notch and communicating between the first end portion and the second end portion in the axis direction. A minimum flow cross-sectional area of the vent passage matches an opening area of the notch in an end surface on the second end portion side.

Abstract: In a laser processing method, laser lights of fiber lasers or direct diode lasers is irradiated onto an iron-based plate material from a nozzle, a nozzle with a nozzle opening whose opening diameter is preliminarily set according to a thickness of the plate material is selected from plural nozzles whose nozzle openings have different opening diameters from each other, and the plate material is cut while irradiating the laser lights onto the plate material and injecting assist gas from the nozzle opening toward the plate material.

Abstract: In a laser processing method, laser lights of fiber lasers or direct diode lasers is irradiated onto an iron-based plate material from a nozzle, a nozzle with a nozzle opening whose opening diameter is preliminarily set according to a thickness of the plate material is selected from plural nozzles whose nozzle openings have different opening diameters from each other, and the plate material is cut while irradiating the laser lights onto the plate material and injecting assist gas from the nozzle opening toward the plate material.

Abstract: A laser cutting nozzle includes an inner nozzle and an outer nozzle. The inner nozzle exhibits a tube shape having a through hole on an axis and having a diameter decreasing on a first end portion side and includes a notch extending in the axis direction along an outer peripheral surface on a second end portion side. The outer nozzle is fitted to the outer peripheral surface of the inner nozzle and includes a vent passage including the notch and communicating between the first end portion and the second end portion in the axis direction. A minimum flow cross-sectional area of the vent passage matches an opening area of the notch in an end surface on the second end portion side.

Abstract: A period of time during which a laser beam moves through an inner region of a beam spot that ranges from a center of the beam spot to an area corresponding to a thermal energy of 44% with respect to a total thermal energy of the beam spot is set as a moving time tp. “c”, “?”, “?”, “T”, “T0”, “A”, and “Pd” respectively represents a specific heat, a density, a thermal conductivity, a melting temperature, an environmental temperature, a light absorptance, and an energy density of the inner region. A time calculated from Equation (1) is set as a melting time tm. A plate thickness is represented by x and a value of tm/tp is represented by y. The value y is set between a lower limit value (Equation (2)) and an upper limit value (Equation (3)). tm=c×?×?×?[(T?T0)/(2×A×Pd)]2??(1) y=0.0027e0.36x??(2) y=0.0026e0.

Abstract: A laser processing machine includes a laser oscillator. The laser oscillator excites a laser beam having a wavelength in a 1 ?m band or a shorter wavelength band. One process fiber transmits the laser beam emitted from the laser oscillator. A focusing optical element focuses, when a workpiece is irradiated with the laser beam emitted from the process fiber, the laser beam on a plurality of spots in a unit area within a unit time, the unit area having a radius of 0.5 mm of an optical axis of the laser beam, and the unit time being a time from when the workpiece starts to melt to when the melting of the workpiece ends.

Abstract: A period of time during which a laser beam moves through an inner region of a beam spot that ranges from a center of the beam spot to an area corresponding to a thermal energy of 44% with respect to a total thermal energy of the beam spot is set as a moving time tp. “c”, “?”, “?”, “T”. “T0”, “A”, and “Pd” respectively represents a specific heat, a density, a thermal conductivity, a melting temperature, an environmental temperature, a light absorptance, and an energy density of the inner region. A time calculated from Equation (1) is set as a melting time tm. A plate thickness is represented by x and a value of tm/tp is represented by y. The value y is set between a lower limit value (Equation (2)) and an upper limit value (Equation (3)). tm=c×?×?×?[(T?T0)/(2×A×Pd)]2 ??(1) y=0.0027e0.36x ??(2) y=0.0026e0.

Abstract: A laser processing machine includes a laser oscillator. The laser oscillator excites a laser beam having a wavelength in a 1 ?m band or a shorter wavelength band. One process fiber transmits the laser beam emitted from the laser oscillator. A focusing optical element focuses, when a workpiece is irradiated with the laser beam emitted from the process fiber, the laser beam on a plurality of spots in a unit area within a unit time, the unit area having a radius of 0.5 mm of an optical axis of the laser beam, and the unit time being a time from when the workpiece starts to melt to when the melting of the workpiece ends.