WO2023085160A1 - Procédé de traitement au laser et dispositif de traitement au laser - Google Patents

Procédé de traitement au laser et dispositif de traitement au laser Download PDF

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Publication number
WO2023085160A1
WO2023085160A1 PCT/JP2022/040736 JP2022040736W WO2023085160A1 WO 2023085160 A1 WO2023085160 A1 WO 2023085160A1 JP 2022040736 W JP2022040736 W JP 2022040736W WO 2023085160 A1 WO2023085160 A1 WO 2023085160A1
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Prior art keywords
sheet metal
laser beam
nozzle
laser
cutting
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PCT/JP2022/040736
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English (en)
Japanese (ja)
Inventor
明彦 杉山
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株式会社アマダ
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Publication of WO2023085160A1 publication Critical patent/WO2023085160A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/36—Removing material
    • B23K26/38—Removing material by boring or cutting

Definitions

  • the present disclosure relates to a laser processing method and a laser processing machine.
  • Patent Document 1 a laser processing machine that performs laser processing using an assist gas has been known (Patent Document 1).
  • the laser processing machine described in Patent Literature 1 makes uniform the pressure distribution in the circumferential direction of the assist gas ejected from the nozzles attached to the laser processing head. As a result, the height of dross generated in the cutting process of the plate material (sheet metal) in the cutting direction is less likely to occur, and the product quality is improved.
  • the laser processing machine described in Patent Document 1 uses a fiber laser whose oscillation wavelength (hereinafter simply referred to as "wavelength") is in the 1 ⁇ m band.
  • a laser beam with a wavelength of 1 ⁇ m or less has a higher absorptance characteristic to the sheet metal due to the incident angle than a laser beam with a wavelength of 10 ⁇ m such as a CO2 laser.
  • Absorption due to reflection within the sheet metal also occurs in the lateral direction on the lower side of the cutting front. Therefore, if the laser beam and the assist gas (oxygen) are not properly supplied to the lower surface of the sheet metal, the thermal cutting due to the oxidation-reduction reaction is not properly performed on the lower surface of the sheet metal, and the bevel amount exceeds the standard.
  • the definition of the bevel amount is the distance between two parallel tangent lines that the cutting surface profile of the cut surface of the sheet metal contacts. , or the shortest distance from the lower end of the cutting surface profile to another tangent line with which the cutting surface profile contacts.
  • the 1 ⁇ m band fiber laser wavelength generally refers to a wavelength band with a fundamental wave of 1060 nm to 1080 nm
  • the 10 ⁇ m band CO2 laser wavelength generally refers to a wavelength band with a fundamental wave of 10600 nm. Point.
  • a laser beam having a wavelength of 1 ⁇ m band or less includes a wavelength band of a green laser or a blue laser in addition to a fiber laser of 1 ⁇ m band.
  • the laser beam melts the metal on the top side of the cutting front, and the laser beam and the oxygen assist gas melt the metal on the cutting front that continues to the top side of the cutting front.
  • the molten metal is discharged from the lower surface of the cutting front by the assist gas flow and its own weight.
  • a laser processing machine smoothly performs a series of these processes. Further, a part of the laser beam with a wavelength of 1 ⁇ m band or less irradiated to the metal surface is reflected within the beam cutting front and contributes to metal melting again on the lower surface side of the cutting front. Also, on the cutting front surface, both the heat energy from the laser beam and the heat energy of the oxidation-reduction reaction by the oxygen assist gas melt the surrounding metal by heat conduction.
  • a laser processing method is a laser processing method in which a sheet metal is irradiated with a laser beam having a wavelength of 1080 nm or less and an assist gas is blown to cut the sheet metal, wherein the focus of the irradiated laser beam
  • the position is set inside the sheet metal, and based on the thickness of the sheet metal, the amplitude of vibration of the laser beam in the horizontal direction with respect to the cutting progress direction of the sheet metal, and the nozzle attached to the processing head, wherein the laser beam determines the opening diameter of the opening of the nozzle through which the assist gas is ejected, and moves the processing head to which the nozzle having the determined opening diameter is attached relative to the sheet metal along the cutting progress direction
  • the laser beam is oscillated in the left-right direction with respect to the cutting progress direction at the set focal position and the determined amplitude from the nozzle having the opening diameter while the laser beam is ejected, and the assist gas is ejected. do.
  • the focal position of the irradiated laser beam is set inside the sheet metal, and the horizontal vibration of the laser beam with respect to the cutting direction of the sheet metal is determined based on the thickness of the sheet metal.
  • the amplitude and the opening diameter of the opening of the nozzle attached to the processing head from which the laser beam is emitted and the assist gas is ejected are determined.
  • the nozzle having the opening diameter emits a laser at the set focal position and the determined amplitude.
  • the beam is oscillated in the horizontal direction with respect to the direction of cutting and ejected, and the assist gas is ejected.
  • the amount of bevel generated on the cut surface of the sheet metal can be reduced, and the dimensional difference between the upper surface side and the lower surface side of the sheet metal can be reduced.
  • a laser processing machine is a laser processing machine that irradiates a sheet metal with a laser beam having a wavelength of 1080 nm or less and sprays an assist gas to cut the sheet metal, and is a nozzle attached to a processing head.
  • the beam vibrating mechanism is operated so as to oscillate the laser beam in the left-right direction with respect to the cutting progress direction at the set focal position and the determined amplitude from the nozzle having the opening diameter while moving the beam vibrating mechanism. and a control unit that controls and ejects the assist gas.
  • a laser processing machine sets the focal position of the laser beam inside the sheet metal, and based on the thickness of the sheet metal, the amplitude of the horizontal vibration of the laser beam with respect to the cutting progress direction, and the nozzle a controller for determining the opening diameter of the opening of the
  • the control unit moves the processing head, to which the nozzle having the determined opening diameter is attached, relative to the sheet metal along the direction of cutting progress, while the nozzle having the opening diameter emits the set focal position and the determined amplitude.
  • the beam vibration mechanism is controlled so that the laser beam is emitted while vibrating in the horizontal direction with respect to the cutting progress direction, and the assist gas is ejected.
  • the amount of bevel generated on the cut surface of the sheet metal can be reduced, and the dimensional difference between the upper surface side and the lower surface side of the sheet metal can be reduced.
  • the amount of bevel generated on the cut surface of the sheet metal is reduced, and the upper surface side and the lower surface side of the sheet metal are reduced. Dimensional difference can be reduced.
  • FIG. 1 is a diagram showing an overall configuration example of a laser processing machine according to an embodiment.
  • FIG. 2 is a perspective view showing a detailed configuration example of a collimator unit and a processing head in the laser processing machine according to the embodiment;
  • FIG. 3 is a diagram showing the displacement of the irradiation position of the laser beam on the sheet metal by the beam vibration mechanism.
  • FIG. 4 is a graph showing the relationship between the plate thickness of the sheet metal and the lateral amplitude of the laser beam with respect to the direction in which cutting progresses.
  • FIG. 5A is a diagram showing an orthogonal vibration pattern of a laser beam.
  • FIG. 5B is a diagram showing a circular oscillation pattern of a laser beam.
  • FIG. 5C is a diagram showing a C-shaped oscillation pattern of a laser beam.
  • FIG. 6 is a diagram showing an actual vibration pattern when using the orthogonal vibration pattern shown in FIG. 5A.
  • FIG. 7A is a graph showing the relationship between the opening diameter of the nozzle and the dimensional difference in the vertical direction of the sheet metal at a predetermined thickness of the sheet metal measured by experiment (No. 1).
  • FIG. 7B is a graph showing the relation between the opening diameter of the nozzle and the dimensional difference in the vertical direction of the sheet metal at a predetermined thickness of the sheet metal measured by experiment (No. 2).
  • FIG. 8 is a graph showing the optimum nozzle opening diameter for each sheet metal thickness obtained from the measurement results of FIGS. 7A and 7B.
  • FIG. 9 is a schematic diagram showing an example of a cross-sectional shape of a sheet metal formed by conventional laser processing.
  • the laser processing method and laser processing machine are mild steel plates and are suitable for cutting sheet metal having a thickness of 16 mm or more.
  • a laser processing machine and a laser processing method according to one embodiment will be described with reference to the drawings. In the description of the drawings, the same parts are denoted by the same reference numerals, and the description thereof is omitted.
  • FIG. 1 is a diagram showing an overall configuration example of a laser processing machine 100 according to an embodiment. An overall configuration example of a laser processing machine 100 will be described with reference to FIG.
  • a laser processing machine 100 includes a laser oscillator 10 , a laser processing unit 20 , and a process fiber 12 that transmits a laser beam emitted from the laser oscillator 10 to the laser processing unit 20 .
  • the process fiber 12 may be single-core or multi-clad, and may have an optical coupler on the transmission path to the laser processing unit 20 .
  • the laser processing machine 100 also includes an operation unit 40, an NC (Numerical Control) device 50, a processing program database 60, a processing condition database 70, and an assist gas supply device 80.
  • the NC device 50 is an example of a control device (control section) that controls each section of the laser processing machine 100 .
  • the laser oscillator 10 generates and emits a laser beam.
  • a laser oscillator that amplifies excitation light emitted from a laser diode and emits a laser beam of a predetermined wavelength, or a laser oscillator that directly uses the laser beam emitted from the laser diode is suitable.
  • the laser oscillator 10 is, for example, a solid-state laser oscillator, a fiber laser oscillator, a disk laser oscillator, or a direct diode laser oscillator (DDL oscillator).
  • the laser oscillator 10 emits a 1 ⁇ m band laser beam with a wavelength of 900 nm to 1080 nm.
  • the fiber laser oscillator emits a laser beam with a wavelength of 1060 nm to 1080 nm
  • the DDL oscillator emits a laser beam with a wavelength of 910 nm to 950 nm.
  • the laser oscillator 10 may emit a laser beam having a wavelength of 300 nm or more and 1080 nm or less. Lasers with wavelengths of 300 nm or more and 1080 nm or less include green lasers and blue lasers in addition to fiber lasers.
  • the laser processing unit 20 includes a processing table 21 on which a sheet metal W to be processed is placed, a gate-shaped X-axis carriage 22, a Y-axis carriage 23, a collimator unit 30 fixed to the Y-axis carriage 23, and a processing head 35.
  • the laser processing unit 20 has a nozzle 36 having a circular opening 36a attached to the processing head 35, and has a plurality of nozzles with different opening diameters for the opening 36a. It is configured so that a nozzle 36 having an optimum opening diameter for cutting can be selected.
  • the nozzle 36 may be automatically attached to the processing head 35 by a nozzle changer (not shown) provided in the laser processing machine 100, or may be attached by an operator.
  • the assist gas supply device 80 supplies oxygen as an assist gas to the processing head 35 .
  • the X-axis carriage 22 is configured to be movable on the processing table 21 in the X-axis direction.
  • the Y-axis carriage 23 is configured to be movable on the X-axis carriage 22 in the Y-axis direction perpendicular to the X-axis.
  • the X-axis carriage 22 and the Y-axis carriage 23 are moving mechanisms that move the machining head 35 along the surface of the sheet metal W in the X-axis direction, the Y-axis direction, or any combination of the X-axis and the Y-axis. Function.
  • the processing head 35 may be configured such that the position of the processing head 35 is fixed and the sheet metal W moves. That is, the laser processing machine 100 only needs to have a moving mechanism that moves the processing head 35 relative to the surface of the sheet metal W.
  • the collimator unit 30 has a collimation mechanism that converts the diverging laser beam emitted from the process fiber 12 into parallel light (collimated light), and a beam oscillation mechanism that oscillates the laser beam irradiated onto the sheet metal W. Details of the collimator unit 30 will be described later with reference to FIGS.
  • a nozzle 36 having a circular opening 36 a is detachably attached to the processing head 35 .
  • a laser beam is emitted from an opening 36a of the nozzle 36, and an assist gas (oxygen) is ejected.
  • the sheet metal W is irradiated with the laser beam emitted from the opening 36a, and the ejected oxygen is blown onto the sheet metal W. As shown in FIG.
  • the oxygen blown onto the sheet metal W promotes an oxidation-reduction reaction to cause thermal cutting of the sheet metal W, and discharges the molten metal of the sheet metal W from the kerf.
  • the processing head 35 is configured such that the assist gas is ejected coaxially with the laser beam emitted from the opening 36a of the nozzle 36 in a state in which the beam vibration mechanism in the collimator unit 30 is not operated. Details of the processing head 35 will be described later with reference to FIGS.
  • the operation unit 40 and the display unit 90 are used to input processing conditions that must be input to the NC device 50 when cutting the sheet metal W, and to set the laser processing machine 100 determined based on the input processing conditions.
  • the operation unit 40 is composed of a touch panel or a keyboard, and can input processing conditions to the NC device 50 .
  • the processing conditions are, for example, the thickness of the sheet metal W, the material of the sheet metal W, the power of the laser beam, and the processing speed.
  • the display unit 90 is a monitor that displays input items to the NC unit 50 and setting values determined based on the input items.
  • the machining program database 60 stores machining programs for the NC device 50 to operate each component of the laser processing machine 100 .
  • the processing program is program code that defines the operation procedure of the laser processing machine 100 .
  • the processing condition database 70 stores a plurality of processing condition files in which a plurality of parameters necessary for cutting the sheet metal W are registered.
  • a machining condition file is a file that defines each parameter in a machining program.
  • the processing condition database 70 stores the processing condition file 1 that defines the horizontal vibration pattern of the laser beam with respect to the direction in which the sheet metal W is cut. Details of the oscillation pattern of the laser beam defined in the processing condition file 1 will be described later with reference to FIGS. 5A to 6. FIG.
  • the processing condition database 70 stores a processing condition file 2 that defines the amplitude of vibration of the laser beam in the left-right direction with respect to the cutting direction for each thickness of the sheet metal W. The details of the amplitude of the vibration of the laser beam in the left-right direction with respect to the cutting direction for each thickness of the sheet metal W defined in the processing condition file 2 will be described later with reference to FIG.
  • the processing condition database 70 also stores a processing condition file 3 that defines the opening diameter of the opening 36a of the nozzle 36 for each thickness of the sheet metal W (hereinafter also referred to as "the opening diameter of the nozzle 36"). The details of the opening diameter of the nozzle 36 for each thickness of the sheet metal W defined in the processing condition file 3 will be described later with reference to FIGS. 7A to 8.
  • FIG. 1 The parameters defined in the processing condition file 2 and the processing condition file 3 reduce the amount of bevel that occurs on the cut surface of the sheet metal W when cutting the sheet metal W, which is obtained in advance by experiments, and the upper surface side of the sheet metal W is reduced. This is the optimal value that can reduce the dimensional difference between and the lower surface side.
  • FIG. 2 is a perspective view showing a detailed configuration example of the collimator unit 30 and the processing head 35 in the laser processing machine 100 according to the embodiment.
  • the collimator unit 30 includes a collimation lens 31 that converts the divergent laser beam emitted from the process fiber 12 into parallel light (collimated light).
  • the divergent laser beam emitted from the process fiber 12 travels so that the center of its optical axis is positioned at the center of the collimation lens 31 .
  • the collimator unit 30 also includes a galvanometer scanner unit 32 and a bend mirror 33 that reflects the laser beam emitted from the galvanometer scanner unit 32 downward in the Z-axis direction perpendicular to the X-axis and the Y-axis.
  • the processing head 35 includes a focusing lens 34 that focuses the laser beam reflected by the bend mirror 33 and irradiates the sheet metal W with the laser beam.
  • the focusing lens 34 is configured to be movable toward and away from the sheet metal W by a driving unit and a moving mechanism (not shown) in order to adjust the focal position of the laser beam.
  • the laser processing machine 100 is centered so that the laser beam emitted from the opening 36a of the nozzle 36 is positioned at the center of the opening 36a. In the reference state, the laser beam is emitted from the center of the opening 36a.
  • the galvanometer scanner unit 32 functions as a beam vibration mechanism that moves within the opening 36a the laser beam that advances through the processing head 35 and is emitted from the opening 36a.
  • the galvanometer scanner unit 32 has a scan mirror 321 that reflects the laser beam emitted from the collimation lens 31, and a drive section 322 that rotates the scan mirror 321 to a predetermined angle.
  • the galvanometer scanner unit 32 also has a scan mirror 323 that reflects the laser beam emitted from the scan mirror 321, and a drive unit 324 that rotates the scan mirror 323 to a predetermined angle.
  • the drive units 322 and 324 can reciprocate the scan mirrors 321 and 323 respectively within a predetermined angle range based on the control by the NC device 50 .
  • the galvanometer scanner unit 32 vibrates the laser beam with which the sheet metal W is irradiated by reciprocatingly oscillating either one or both of the scan mirror 321 and the scan mirror 323 .
  • the illustrated galvano-scanner unit 32 is an example of the beam vibration mechanism, and the beam vibration mechanism is not limited to the galvano-scanner unit 32 having a pair of scan mirrors.
  • the beam oscillation mechanism may consist of one scan mirror, or three or more scan mirrors.
  • FIG. 3 is a diagram showing the displacement of the irradiation position of the laser beam on the sheet metal W by the beam vibration mechanism.
  • the displacement of the irradiation position of the laser beam on the sheet metal W by the beam vibration mechanism will be described with reference to FIG.
  • FIG. 3 shows a state in which one or both of the scan mirror 321 and the scan mirror 323 are tilted and the position of the laser beam with which the sheet metal W is irradiated is displaced.
  • the thin solid line that is bent by the bend mirror 33 and passes through the focusing lens 34 indicates the optical axis of the laser beam when the laser processing machine 100 is in the standard state.
  • the operation of the galvanometer scanner unit 32 located in front of the bend mirror 33 changes the angle of the optical axis of the laser beam incident on the bend mirror 33, and the optical axis is shifted from the center of the bend mirror 33. get off.
  • the incident position of the laser beam on the bend mirror 33 is the same before and after the operation of the galvanometer scanner unit 32 .
  • the optical axis of the laser beam is displaced from the position indicated by the thin solid line to the position indicated by the thick solid line due to the action of the galvanometer scanner unit 32 .
  • the laser beam reflected by the bend mirror 33 is inclined at an angle ⁇
  • the irradiation position of the laser beam on the sheet metal W is displaced by a distance ⁇ s.
  • the focal length of the condenser lens 34 is EFL (Effective Focal Length)
  • the distance ⁇ s is calculated by EFL ⁇ sin ⁇ .
  • the galvanometer scanner unit 32 tilts the laser beam by an angle ⁇ in the direction opposite to the direction shown in FIG. 3, the irradiation position of the laser beam on the sheet metal W is displaced by a distance ⁇ s in the direction opposite to the direction shown in FIG. be able to.
  • the distance ⁇ s is less than the radius of the opening 36a, preferably less than or equal to the maximum distance obtained by subtracting a predetermined margin from the radius of the opening 36a.
  • the NC device 50 can vibrate the laser beam in a predetermined direction within the plane of the sheet metal W by controlling the drive units 322 and 324 of the galvano scanner unit 32 .
  • the NC device 50 can vibrate the beam spot formed on the surface of the sheet metal W by vibrating the laser beam.
  • FIG. 9 is a schematic diagram showing an example of a cross-sectional shape of a sheet metal W produced by conventional laser processing.
  • the conventional laser processing in order to obtain a kerf width corresponding to the sheet metal thickness, it is necessary to increase the laser beam irradiation diameter from the sheet metal upper surface toward the sheet metal lower surface as the sheet metal thickness increases.
  • the energy density on the upper surface of the sheet metal must be reduced by selecting defocusing, in which the focus position of the laser beam is shifted upward from the upper surface of the sheet metal, or infocus, in which the focal position is shifted into the inside of the sheet metal. If the energy density on the upper surface of the sheet metal is too low, the metal cannot be melted, so the laser output must be increased. As a result, the total amount of energy irradiated to the sheet metal increases, and the laser beam that was not absorbed (reflected) by the upper surface of the sheet metal is irradiated again in the side direction of the lower surface of the sheet metal in the cutting front and absorption occurs. .
  • the laser beam and oxygen assist gas melt the metal on the cutting front that continues from the top side of the cutting front, and the molten metal is discharged from the bottom side of the cutting front by the assist gas flow and its own weight.
  • the amount of molten metal discharged from the lower surface side of the cutting front exceeds the amount suitable for the volume of the cutting front in the sheet metal W in which more than the appropriate amount of heat energy has been accumulated, or when the amount of molten metal discharged from the lower surface side of the cutting front exceeds
  • thermal energy is received, a bevel amount exceeding the standard is generated, and a dimensional difference is generated between the upper surface side and the lower surface side of the sheet metal W.
  • the appropriate nozzle opening diameter for the plate thickness is defined in the processing condition file 2 stored in the NC unit 50.
  • FIG. The tendency of the nozzle opening diameter to increase as the plate thickness increases has not changed since the time when the laser source was a carbon dioxide laser.
  • the NC unit 50 measures the amplitude of vibration of the laser beam in the horizontal direction with respect to the direction in which the sheet metal W is cut (hereinafter also referred to as the “horizontal amplitude of the laser beam”) based on the thickness of the sheet metal W. ), and the opening diameter of the opening 36 a of the nozzle 36 .
  • the NC unit 50 moves the processing head 35, to which the nozzle 36 having the determined opening diameter is attached, along the direction of cutting progress, while emitting a laser beam with the determined amplitude from the nozzle 36 having the opening diameter in the direction of cutting progress.
  • the beam vibration mechanism is controlled so that the beam is emitted while vibrating in the horizontal direction, and the assist gas is ejected. The details of each process of the laser processing machine 100 will be described below.
  • the NC unit 50 determines the amplitude of vibration of the laser beam in the horizontal direction with respect to the direction in which the sheet metal W is cut, and the opening diameter of the nozzle 36 . Specifically, the NC unit 50 displays a screen for inputting the thickness of the sheet metal W on the display unit 90 and acquires the thickness of the sheet metal W input by the operator from the operation unit 40 .
  • the NC unit 50 refers to the processing condition file 2 stored in the processing condition database 70 that defines the amplitude of the laser beam in the left-right direction with respect to the cutting direction for each thickness of the sheet metal W.
  • the horizontal amplitude of the laser beam corresponding to the thickness of the sheet metal W is obtained from the inside. As a result, the amplitude of vibration of the laser beam in the left-right direction with respect to the direction of progress of cutting, which is optimum for the thickness of the sheet metal W, is determined.
  • FIG. 4 is a graph showing the relationship between the thickness of the sheet metal W and the amplitude of the laser beam in the left-right direction with respect to the cutting direction.
  • the NC unit 50 increases the amplitude of the laser beam in the left-right direction with respect to the cutting progress direction as the plate thickness of the sheet metal W increases. That is, the kerf width formed in the sheet metal W increases as the sheet metal W increases in thickness.
  • the focal position of the laser beam may be set inside the sheet metal so that the laser beam irradiation diameter does not change between the sheet metal upper surface and the sheet metal lower surface.
  • the center of the amplitude of the laser beam in the horizontal direction with respect to the direction of cutting may coincide with the center of the nozzle, or the center of the amplitude may precede the center of the nozzle in the direction of cutting.
  • the NC unit 50 refers to the processing condition file 1 and determines the vibration pattern of the laser beam when vibrating the laser beam in the left-right direction with the determined amplitude.
  • FIGS. 5A to 6 examples of vibration patterns of the laser beam in the left-right direction with respect to the cutting progress direction of the sheet metal W defined in the processing condition file 1 will be described.
  • 5A to 5C show vibration patterns in a state in which the processing head 35 is not moved in the direction in which cutting progresses, so that the vibration patterns can be easily understood.
  • the cutting progress direction of the sheet metal W is defined as the x direction
  • the direction orthogonal to the x direction within the plane of the sheet metal W is defined as the y direction.
  • the NC device 50 vibrates the laser beam in one of the vibration patterns shown in FIGS. 5A to 5C.
  • FIG. 5A is a diagram showing an orthogonal vibration pattern of a laser beam.
  • the orthogonal vibration pattern shown in FIG. 5A vibrates the beam spot Bs formed on the sheet metal W in the direction (y direction) perpendicular to the cutting direction (x direction).
  • a kerf Wk is formed by laser beam irradiation.
  • FIG. 5B is a diagram showing a circular oscillation pattern of a laser beam.
  • the circular vibration pattern shown in FIG. 5B circularly vibrates the beam spot Bs formed on the sheet metal W.
  • FIG. 5C is a diagram showing a C-shaped oscillation pattern of a laser beam. In the C-shaped vibration pattern shown in FIG.
  • the beam spot Bs formed on the sheet metal W is vibrated so as to draw the letter "C".
  • the oscillation pattern of the laser beam is not limited to this.
  • the laser beam may oscillate in the left-right direction with respect to the cutting progress direction (x-direction) of the sheet metal W, and may be, for example, a figure-eight trajectory or an elliptical trajectory.
  • FIG. 6 is a diagram showing an actual vibration pattern when using the orthogonal vibration pattern shown in FIG. 5A.
  • the beam spot Bs vibrates in the y direction while moving in the x direction, so the actual orthogonal vibration pattern is a vibration pattern as shown in FIG.
  • the NC unit 50 refers to the processing condition file 3, which is stored in the processing condition database 70 and defines the opening diameter of the nozzle 36 for each thickness of the sheet metal W, and selects the sheet metal W from the processing condition file 3. Acquire the opening diameter of the nozzle 36 corresponding to the thickness. As a result, the optimal nozzle opening diameter for the thickness of the sheet metal W is determined.
  • the NC device 50 controls the nozzle changer so as to attach the nozzle 36 having the determined opening diameter to the machining head 35 . Alternatively, the opening diameter of the nozzle 36 attached to the processing head 35 is displayed on the display unit 90 to notify the operator to attach the nozzle 36 having the optimum opening diameter.
  • FIG. Machining condition file 3 is obtained by performing cutting using a plurality of nozzles having different opening diameters for openings 36a for each thickness of sheet metal W in advance in an experiment, and using nozzles 36 with different opening diameters. The dimensional difference is measured and obtained based on the opening diameter of the nozzle 36 with the smallest dimensional difference for each plate thickness. Note that the amplitude of the laser beam in the left-right direction with respect to the cutting direction during cutting in the experiment is the value shown in FIG.
  • FIG. 7A is a graph showing the relationship between the opening diameter (nozzle diameter) of the nozzle 36 and the dimensional difference in the vertical direction (upper surface side and lower surface side) of the sheet metal W at a predetermined thickness of the sheet metal W measured by experiment ( Part 1).
  • the dimensional difference between the upper surface side and the lower surface side of the sheet metal W due to the opening diameter of the nozzle 36 and the bevel amount generated on the cut surface of the sheet metal W is measured.
  • the plotted points are actual measurements. As shown in FIG.
  • the dimensional difference between the upper surface side and the lower surface side of the sheet metal W is 0 when the opening diameter of the nozzle 36 is 1.8 mm. It can be seen that the dimensional difference between the upper surface side and the lower surface side of the sheet metal W increases around the nozzle 36 of 1.8 mm.
  • the shape of the kerf Wk is such that the dimension on the upper surface side of the sheet metal is smaller than that on the lower surface side. It becomes a shape whose dimension is larger than that of the lower surface side.
  • the opening diameter of the nozzle 36 is less than 1.8 mm, the amount of oxygen supplied to the lower surface side of the sheet metal W is insufficient, and the amount of molten metal of the sheet metal W due to the oxidation-reduction reaction is insufficient. It can be determined that the gas flow does not have enough force to wash away the molten metal on the lower side of the cutting front. Further, when the opening diameter of the nozzle 36 is larger than 1.8 mm, it is judged that the amount of oxygen supplied to the lower surface side of the sheet metal W is excessive and the amount of molten metal of the sheet metal W due to oxidation-reduction reaction is excessive. can. Further, as indicated by the dashed line in FIG. 7A, it can be seen that the relationship between the opening diameter of the nozzle 36 and the dimensional difference in the vertical direction of the sheet metal W can be linearly approximated.
  • FIG. 7B is a graph showing the relationship between the opening diameter of the nozzle 36 and the vertical dimensional difference of the sheet metal W at a predetermined thickness of the sheet metal W measured by experiment (No. 2).
  • the sheet metal W having a thickness of 22 mm is cut, the dimensional difference between the upper surface side and the lower surface side of the sheet metal W due to the opening diameter of the nozzle 36 and the bevel amount generated on the cut surface of the sheet metal W.
  • the plotted points are actual measurements.
  • FIG. 7B even when the plate thickness of the sheet metal W is 22 mm, it can be seen that there is a tendency similar to the case where the plate thickness is 16 mm shown in FIG. 7A. That is, the dimensional difference between the upper surface side and the lower surface side of the sheet metal W changes linearly around the opening diameter of the nozzle 36 of 2.4 mm where the dimensional difference between the upper surface side and the lower surface side of the sheet metal W becomes 0.
  • FIG. 8 is a graph showing the optimum opening diameter of the nozzle 36 for each thickness of the sheet metal W obtained from the measurement results of FIGS. 7A and 7B.
  • the optimum opening diameter of the nozzle 36 for each thickness of the sheet metal W obtained from the measurement results of FIGS. 7A and 7B will be described with reference to FIG.
  • the points plotted on the left side of FIG. 8 are the opening diameters of the nozzle 36 at which the dimensional difference between the upper surface side and the lower surface side of the sheet metal W becomes 0 when cutting the sheet metal W having a thickness of 16 mm.
  • FIGS. 7A and 7B it is known that the relationship between the opening diameter of the nozzle 36 and the dimensional difference in the vertical direction of the sheet metal W can be linearly approximated. Therefore, as shown in FIG. 8, the opening diameter of the nozzle 36 when the plate thickness of the sheet metal W is 16 mm and the nozzle when the plate thickness is 22 mm, where the dimensional difference between the upper surface side and the lower surface side of the sheet metal W is 0. 36 can be defined as the optimum nozzle diameter for each thickness of the sheet metal W.
  • the NC unit 50 increases the opening diameter of the nozzle 36 as the thickness of the sheet metal W increases, and linearly changes the opening diameter with respect to the change in the thickness of the sheet metal W.
  • FIG. 7A and 7B it is known that the relationship between the opening diameter of the nozzle 36 and the dimensional difference
  • the appropriate nozzle opening diameter for conventional laser processing is 4 mm when the thickness of the sheet metal is 16 mm. This is a case where the method of irradiating by oscillating the laser beam in the lateral direction with respect to the cutting direction of the sheet metal as in the present embodiment is not performed, and the nozzle opening diameter is obviously made larger than in the case of the present embodiment. I needed it.
  • the straight line connecting the opening diameter of the nozzle 36 when the sheet metal W has a thickness of 16 mm and the opening diameter of the nozzle 36 when the sheet metal W has a thickness of 22 mm is , where y is the opening diameter of the nozzle 36 and x is the thickness of the sheet metal W, the following calculation formula (1) is obtained. Therefore, the NC device 50 determines the opening diameter of the nozzle 36 based on the calculation formula (1).
  • the NC unit 50 moves the processing head 35, to which the nozzle 36 having the determined opening diameter is attached, along the direction of cutting progress, while emitting a laser beam with the determined amplitude from the nozzle 36 having the opening diameter in the direction of cutting progress.
  • the beam vibration mechanism is controlled so that the beam is emitted while vibrating in the horizontal direction, and the assist gas is ejected.
  • the NC device 50 controls the gate-shaped X-axis carriage 22 and Y-axis carriage 23, which are moving mechanisms, to move the processing head 35, to which the nozzle 36 having the determined opening diameter is attached, along the cutting direction.
  • the NC device 50 oscillates and emits a laser beam in the left-right direction with the determined amplitude from the nozzle 36 having the determined opening diameter while moving the processing head 35 along the cutting direction. It controls the galvanometer scanner unit 32, which is a beam vibration mechanism. The NC device 50 controls the assist gas supply device 80 so as to cause the laser beam to oscillate in the lateral direction with respect to the direction in which the cutting progresses with the determined amplitude, and to eject the assist gas.
  • the focal position of the laser beam to be irradiated is set inside the sheet metal.
  • the diameter of the opening of the nozzle to be attached, through which the laser beam is emitted and the assist gas is ejected, is determined.
  • the set focal position and the determined The laser beam is oscillated in the left-right direction with respect to the cutting progress direction by the amplitude, and the assist gas is jetted out.
  • the laser processing machine sets the focal position of the irradiated laser beam inside the sheet metal. Thereby, the irradiation diameter of the laser beam can be prevented from changing between the upper surface side and the lower surface side of the sheet metal. That is, by preventing the irradiation diameter of the laser beam from changing between the upper surface side and the lower surface side of the sheet metal, the dimensional difference between the upper surface side and the lower surface side of the sheet metal can be reduced. Furthermore, the laser processing machine oscillates and emits a laser beam in the horizontal direction with respect to the direction in which the sheet metal is cut, with an amplitude determined based on the thickness of the sheet metal. Width can be set.
  • the laser processing machine can reduce the bevel amount generated on the cut surface of the sheet metal, and can reduce the dimensional difference between the upper surface side and the lower surface side of the sheet metal due to the bevel amount generated on the cut surface of the sheet metal.
  • the laser processing machine oscillates the laser beam in the left-right direction with respect to the direction in which the sheet metal is cut, with an amplitude determined based on the thickness of the sheet metal. can be reduced.
  • the laser processing machine can prevent the laser beam from being excessively absorbed in the lateral direction of the lower surface of the sheet metal within the cutting front. Therefore, it is possible to reduce excessive metal melting of the sheet metal due to the laser beam and metal melting due to excessive oxidation-reduction reaction due to the assist gas in the lateral direction of the lower surface of the sheet metal. That is, the laser processing machine can reduce the bevel amount generated on the cut surface of the sheet metal, and can reduce the dimensional difference between the upper surface side and the lower surface side of the sheet metal.
  • the laser processing machine sprays assist gas onto the sheet metal from a nozzle having an opening diameter determined based on the thickness of the sheet metal. can be properly controlled. Therefore, the laser processing machine can appropriately control the metal melting of the sheet metal due to the oxidation-reduction reaction on the lower surface side of the sheet metal promoted by the assist gas according to the thickness of the sheet metal. That is, the laser processing machine can reduce the bevel amount generated on the cut surface of the sheet metal, and can reduce the dimensional difference between the upper surface side and the lower surface side of the sheet metal.
  • the opening diameter of the nozzle is increased as the thickness of the sheet metal increases, and changes linearly with changes in the thickness of the sheet metal.
  • assist gas is jetted from a nozzle having an appropriate opening diameter, and the assist gas is supplied to the lower surface side of the sheet metal.
  • the amount should be properly controlled.
  • the flow of the assist gas differs between the center and the ends of the nozzle opening. Specifically, the assist gas ejected from the end of the nozzle opening diffuses to the surroundings and the flow velocity drops rapidly, but the flow of the assist gas ejected from the center side of the nozzle opening is stable. , stably flows to the cutting front.
  • the laser processing machine increases the opening diameter of the nozzle as the plate thickness of the sheet metal increases, and by linearly changing the nozzle opening diameter with respect to the change in the plate thickness of the sheet metal, assists with an appropriate supply amount to the lower surface side of the sheet metal. Gas can be supplied, and metal melting of the sheet metal due to oxidation-reduction reaction on the lower surface side of the sheet metal can be appropriately controlled. That is, the laser processing machine can reduce the bevel amount generated on the cut surface of the sheet metal, and can reduce the dimensional difference between the upper surface side and the lower surface side of the sheet metal.
  • the laser processing machine calculates the opening diameter of the nozzle using the calculation formula (1).
  • the opening diameter of the nozzle which is an approximate expression obtained from experiments, it is possible to determine a nozzle having an optimum opening diameter according to the plate thickness of the sheet metal.
  • the present embodiment can be processed with a nozzle opening diameter smaller than that of the conventional processing method, a secondary effect of reducing the consumption of assist gas is also recognized.
  • the laser processing machine increases the amplitude of the laser beam in the horizontal direction with respect to the cutting direction of the sheet metal as the thickness of the sheet metal increases.
  • the thicker the sheet metal the larger the kerf width can be formed, and the thicker the sheet metal, the more melted material generated during the cutting process can be easily discharged. dross adhering to the lower surface side of the sheet metal can be reduced. That is, the laser processing machine can reduce the bevel amount generated on the cut surface of the sheet metal, and can reduce the dimensional difference between the upper surface side and the lower surface side of the sheet metal.
  • the laser processing machine irradiates a laser beam with a wavelength of 300 nm or more and 1080 nm or less.
  • the energy density is higher than that of a laser beam with a wavelength of 10 ⁇ m, such as a CO2 laser, and cutting can be performed at a higher speed.
  • a laser beam with a wavelength of 1080 nm or less has a higher energy conversion efficiency than a CO2 laser, and can reduce the cost of cutting sheet metal.
  • thermal energy is supplied into the cutting front without increasing the total amount of energy when irradiating the sheet metal with the focal position shifted for the purpose of expanding the kerf width. be able to.
  • the laser processing machine ejects assist gas from the same axis as the laser beam emitted from the nozzle opening.
  • the center of the amplitude in the horizontal direction of the laser beam and the center of the nozzle with respect to the cutting direction may precede the center of the nozzle in the cutting direction.
  • the assist gas flow is a fluid with enough force to push the molten metal away. I can assure you that there is.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Laser Beam Processing (AREA)

Abstract

L'emplacement de point focal d'un faisceau laser rayonnant est défini dans une section intérieure d'un métal en feuille, et l'amplitude d'oscillation du faisceau laser dans une direction gauche/droite et le diamètre d'ouverture d'une ouverture (36a) d'une buse (36) à travers laquelle le faisceau laser est émis et un gaz d'assistance est éjecté sont déterminés sur la base de l'épaisseur de feuille du métal en feuille, ladite oscillation étant relative à la direction de progression de la coupe du métal en feuille, et ladite buse (36) étant fixée à une tête de traitement (35). Tandis que la tête de traitement (35) qui comporte la buse (36) avec le diamètre d'ouverture déterminé fixée à celle-ci est déplacée par rapport au métal en feuille le long de la direction de progression de la coupe, le faisceau laser oscille dans la direction gauche/droite par rapport à la direction de progression de la coupe et émis, à l'aide de l'emplacement de point focal défini et de l'amplitude déterminée, à partir de la buse (36) avec le diamètre d'ouverture déterminé, et le gaz d'assistance est éjecté à partir de celle-ci.
PCT/JP2022/040736 2021-11-09 2022-10-31 Procédé de traitement au laser et dispositif de traitement au laser WO2023085160A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017192986A (ja) * 2016-04-14 2017-10-26 株式会社アマダホールディングス レーザ加工機及びレーザ加工方法
WO2020085279A1 (fr) * 2018-10-22 2020-04-30 株式会社アマダホールディングス Dispositif d'usinage laser et procédé d'usinage laser

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017192986A (ja) * 2016-04-14 2017-10-26 株式会社アマダホールディングス レーザ加工機及びレーザ加工方法
WO2020085279A1 (fr) * 2018-10-22 2020-04-30 株式会社アマダホールディングス Dispositif d'usinage laser et procédé d'usinage laser

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