WO2023166730A1

WO2023166730A1 - Laser processing head and laser processing device

Info

Publication number: WO2023166730A1
Application number: PCT/JP2022/009507
Authority: WO
Inventors: 直幸中村; 弘菊池
Original assignee: 三菱電機株式会社
Priority date: 2022-03-04
Filing date: 2022-03-04
Publication date: 2023-09-07
Also published as: JP7138827B1; JPWO2023166730A1

Abstract

A laser processing head (3) is provided in a laser processing device (1) that locally melts a workpiece (4) by irradiation with laser light (L) and that uses jetting of a processing gas to remove a molten product produced in the melting. The laser processing head (3) is provided with a gas-filled chamber (10) filled with a processing gas and is provided with: a casing (5) that houses therein a processing lens (7) for condensing the laser light (L); a nozzle (6) that is attached to the casing (5) and through which the laser light (L) to be radiated on the workpiece (4) and the processing gas to be jetted from the gas-filled chamber (10) to the workpiece (4) pass; and an ultrasonic wave generation unit (11) that generates an ultrasonic wave for oscillating the processing gas in the gas-filled chamber (10). The laser processing head (3) removes a molten product by the processing gas with ultrasonic oscillation being applied.

Description

Laser processing head and laser processing equipment

The present disclosure relates to a laser processing head of a laser processing apparatus and a laser processing apparatus that cuts a work by locally melting the work by irradiating it with a laser beam.

In a laser processing device that cuts a work by locally melting the work by irradiating it with a laser beam, the cutting process proceeds while removing the molten material generated by the melting.

Patent Literature 1 discloses laser processing that has a plurality of ultrasonic sources that generate pressure waves by vibrating air, and that removes melt by propagating pressure waves from each ultrasonic source to a processing point of a workpiece. An apparatus is disclosed. In the laser processing apparatus disclosed in Patent Document 1, a plurality of ultrasonic wave sources are arranged around a laser processing head that emits laser light, and pressure waves generated by each ultrasonic wave source are generated at a processing point. converge.

JP 2019-55422 A

Some laser processing devices remove the melt by injecting processing gas from a laser processing head that emits laser light to the processing point. The processing gas injected into the workpiece reaches the molten portion of the workpiece and pushes the molten material out of the workpiece. A laser processing apparatus can efficiently remove molten material from a workpiece by using a processing gas. On the other hand, the laser processing apparatus disclosed in Patent Document 1 does not remove the melted material by injecting the processing gas, so it is possible to efficiently remove the melted material compared to the case where the processing gas is used. is difficult.

In addition, Patent Document 1 discloses a method of using pressure waves as a method of removing melted matter, but does not disclose the use of a processing gas in combination.

The present disclosure has been made in view of the above, and an object thereof is to obtain a laser processing head capable of efficiently removing molten matter generated by melting a workpiece.

In order to solve the above-described problems and achieve the object, the laser processing head according to the present disclosure locally melts a workpiece by irradiating it with a laser beam, and removes the melted matter generated by the melting by injecting a processing gas. It is a laser processing head provided in the processing device. The laser processing head according to the present disclosure includes a housing that includes a gas-filled chamber filled with a processing gas and a processing lens that collects laser light, and a housing that is attached to the housing and irradiates the workpiece. a nozzle through which the laser beam to be applied and the processing gas injected from the gas filling chamber to the workpiece pass; A laser processing head according to the present disclosure removes a melt with a processing gas to which ultrasonic vibrations are applied.

The laser processing head according to the present disclosure has the effect of being able to efficiently remove melted matter generated by melting a workpiece.

1 is a diagram showing a configuration example of a laser processing apparatus according to a first embodiment; FIG. FIG. 4 is a diagram showing an example of an ultrasonic generator provided in the laser processing head of the laser processing apparatus according to the first embodiment; FIG. 11 is a diagram showing a configuration example of a laser processing apparatus according to a second embodiment; FIG. 10 is a diagram showing an example of an ultrasonic generator provided in a laser processing head of a laser processing apparatus according to a second embodiment; FIG. 11 is a diagram for explaining position adjustment of a convergence point of ultrasonic waves by the laser processing apparatus according to the second embodiment; FIG. 1 is a first diagram for explaining intensity distribution adjustment of ultrasonic waves by a laser processing apparatus according to a second embodiment; FIG. 2 is a second diagram for explaining intensity distribution adjustment of ultrasonic waves by the laser processing apparatus according to the second embodiment; FIG. 3 is a third diagram for explaining intensity distribution adjustment of ultrasonic waves by the laser processing apparatus according to the second embodiment; FIG. 10 is a diagram for explaining an example in which the laser processing apparatus according to the second embodiment reduces the intensity distribution and moves the convergence point at high speed; The figure which shows the structural example of the laser processing apparatus concerning Embodiment 3. FIG. 11 is a diagram for explaining position adjustment of a convergence point of ultrasonic waves by the laser processing apparatus according to the fourth embodiment; FIG. 12 is a diagram for explaining an example in which the laser processing apparatus according to the fourth embodiment moves the convergence point in the direction of the optical axis; FIG. 11 is a first diagram for explaining the effect of making the distance between the nozzle and the convergence point longer than the distance between the nozzle and the focal point of the laser light in the fourth embodiment; A second diagram for explaining the effect of making the distance between the nozzle and the convergence point longer than the distance between the nozzle and the focal point of the laser light in the fourth embodiment. FIG. 3 is a third diagram for explaining the effect of making the distance between the nozzle and the convergence point longer than the distance between the nozzle and the focal point of the laser light in the fourth embodiment; FIG. 11 is a diagram showing a portion including a gas rectifying section of the laser processing head according to the fifth embodiment; FIG. 4 is a diagram showing a first configuration example of hardware that implements the ultrasound control unit according to Embodiments 1 to 5; FIG. 10 is a diagram showing a second configuration example of hardware that implements the ultrasound control unit according to Embodiments 1 to 5;

The laser processing head and laser processing apparatus according to the embodiment will be described in detail below with reference to the drawings.

Embodiment 1.
FIG. 1 is a diagram showing a configuration example of a laser processing apparatus 1 according to a first embodiment. The laser processing apparatus 1 cuts the workpiece 4 by locally melting the workpiece 4 by irradiating the laser beam L thereon. The laser processing apparatus 1 removes the melted material from the work 4 by blowing off the melted material produced by melting by jetting a processing gas. The workpiece 4 is a metal plate such as a steel plate.

A laser processing apparatus 1 includes a laser oscillator 2 that outputs a laser beam L and a laser processing head 3 . The laser oscillator 2 is a laser commonly used in industrial laser processing, such as CO ₂ laser, CO laser, fiber laser, semiconductor laser, direct diode laser (DDL), UV (UltraViolet) laser, deep ultraviolet UV laser, and the like. The laser oscillator 2 may be a laser other than the above, and may be a laser of any wavelength band. A laser beam L output from the laser oscillator 2 propagates through an optical path between the laser oscillator 2 and the laser processing head 3 and is introduced into the housing 5 of the laser processing head 3 . A processing lens 7 that condenses the laser beam L and a protective glass 8 that is an optical component for protecting the processing lens 7 are housed inside the housing 5 . Note that the configuration between the laser oscillator 2 and the protective glass 8 is arbitrary.

The housing 5 includes a gas filling chamber 10 filled with processing gas. The laser processing head 3 includes a nozzle 6 through which the laser beam L to irradiate the work 4 and the processing gas injected from the gas filling chamber 10 to the work 4 pass. The laser beam L is emitted from the nozzle 6 toward a processing point on the workpiece 4 where processing is being performed. In Embodiment 1, the processing point is assumed to be the focal point of the laser beam L during processing.

A pipe 9 through which processing gas supplied from a gas supply source passes is connected to the housing 5 . Illustration of the gas supply source is omitted. The processing gas passing through the pipe 9 fills the gas filling chamber 10 . In the example shown in FIG. 1, the gas filling chamber 10 is a portion of the interior of the housing 5 between the nozzle 6 and the protective glass 8 . The processing gas is pressurized in the gas filling chamber 10 and jetted from the nozzle 6 toward the workpiece 4 . The processing gas is oxygen gas, nitrogen gas, or dry air.

The laser processing head 3 has an ultrasonic generator 11 arranged inside the gas filling chamber 10 . The ultrasonic generator 11 generates ultrasonic waves that vibrate the processing gas inside the gas filling chamber 10 . The laser processing apparatus 1 includes an ultrasonic controller 12 that controls the ultrasonic generator 11 . The ultrasonic wave controller 12 converges the ultrasonic waves on the work 4 by controlling the ultrasonic wave generator 11 . The ultrasonic wave generator 11 generates ultrasonic waves that converge on the workpiece 4 under the control of the ultrasonic wave controller 12 . The laser processing head 3 ejects the melted material from the cut portion of the work 4 by jetting the processing gas, and ejects the melted material from the cut portion of the work 4 by applying ultrasonic acoustic radiation pressure to the melted material. As a result, the laser processing apparatus 1 removes the melted matter with the processing gas to which the ultrasonic vibration is applied during processing of the workpiece 4 . The laser processing head 3 can efficiently apply acoustic radiation pressure to the melt by converging ultrasonic waves.

The workpiece 4 is placed on the table and processed. Illustration of the table is omitted. The laser processing apparatus 1 moves the laser processing head 3 relatively to the workpiece 4 by moving at least one of the laser processing head 3 and the table. The laser processing apparatus 1 cuts the work 4 by locally melting the work 4 and moving the laser processing head 3 relative to the work 4 . The laser processing apparatus 1 includes components for driving the laser processing head 3 or the table, components for controlling movement of the laser processing head 3 or the table, and components for controlling the laser oscillator 2. , but illustration of these components is omitted.

FIG. 2 is a diagram showing an example of the ultrasonic generator 11 provided in the laser processing head 3 of the laser processing apparatus 1 according to the first embodiment. The ultrasonic generator 11 is, for example, an ultrasonic transducer. In the example shown in FIG. 2, the ultrasonic transducer is an annular element. The ultrasonic wave generator 11 is arranged so that the center of the ring shape coincides with the optical axis AX of the processing lens. FIG. 2 shows the ultrasonic wave generator 11 when the ultrasonic wave generator 11 is cut along one plane including the optical axis AX.

The ultrasonic waves are converged at one convergence point by the ultrasonic wave generator 11 simultaneously generating ultrasonic waves from the entire annular shape. In the following description, the convergence point is the point at which the intensity of the acoustic radiation pressure due to ultrasonic waves is the highest, that is, the point at which the acoustic radiation pressure due to ultrasonic waves is maximum. In Embodiment 1, the convergence point may be at the same position as the processing point or at a different position from the processing point. The ultrasonic wave generator 11 may have any configuration as long as it can converge the ultrasonic waves.

The ultrasonic wave generator 11 may be a combination of a plurality of elements, each of which is an annular element. Each of the plurality of elements is arranged with the center of the ring aligned with the optical axis AX. That is, the plurality of elements are arranged concentrically. The ultrasonic controller 12 controls each of the plurality of elements. The ultrasonic wave control unit 12 appropriately delays the phase of the ultrasonic wave by adjusting the timing of oscillation of each element. The ultrasonic control unit 12 delays the phase of the ultrasonic waves generated from each element according to the difference in the distance between each element and the convergence point so that the phases of the ultrasonic waves from each element match each other at the convergence point. Let

Assuming that k _i is the angular wave number of ultrasonic waves generated from each element, l _i is the distance from each element to the convergence point, α _i is the timing delay amount of oscillation in each element, and n is an integer, the following equation (1) is obtained. The phases can be aligned at the convergence point by setting the timing delay amount α _i so as to be satisfied. The intensity of the acoustic radiation pressure at the convergence point can be increased by setting the timing delay amount α _i including the characteristic variation of each element or the error of the position where each element is installed.
k _i l _i +α _i =2πn (1)

According to the first embodiment, the laser processing head 3 causes the ultrasonic generator 11 to generate an ultrasonic wave that vibrates the processing gas inside the gas filling chamber 10 , so that the processing gas to which ultrasonic vibration is applied is discharged from the nozzle. 6 to the workpiece 4. Since the pressure of the processing gas, which is a medium, is kept uniform until the processing gas reaches the work 4, the laser processing head 3 can propagate ultrasonic waves to the work 4 with little disturbance. The laser processing head 3 can efficiently propagate ultrasonic waves to the work 4 as compared with the case where the ultrasonic waves are propagated toward the work 4 from the outside of the laser processing head 3 . Therefore, the laser processing head 3 can efficiently apply acoustic radiation pressure to the melt.

When propagating ultrasonic waves from the outside of the laser processing head 3 toward the work 4 , the shorter the distance between the nozzle 6 and the work 4 , the more difficult it is to converge the ultrasonic waves on the work 4 . The laser processing head 3 applies ultrasonic waves to the processing gas inside the gas filling chamber 10 to easily focus the ultrasonic waves on the work 4 even when the distance between the nozzle 6 and the work 4 is short. can be done. As described above, the laser processing head 3 has the effect of being able to efficiently remove the molten material generated by the melting of the workpiece 4 .

The ability of the laser processing apparatus 1 to efficiently remove the melted material makes it possible to improve the processing speed, improve the processing quality, and reduce the consumption of processing gas. The laser processing apparatus 1 can reduce the running cost for processing by being able to reduce the consumption of processing gas.

The laser processing head 3 can be realized by adding the ultrasonic wave generator 11 to the existing laser processing head used for cutting, and design changes from the existing configuration can be reduced. In addition, the laser processing head 3 can be realized without increasing the size of the existing laser processing head and without increasing the manufacturing cost of the existing laser processing head.

Embodiment 2.
FIG. 3 is a diagram showing a configuration example of a laser processing apparatus 1A according to the second embodiment. The laser processing apparatus 1A includes a laser processing head 3A having a configuration different from that of the laser processing head 3 shown in FIG. In the second embodiment, the same reference numerals are assigned to the same components as in the first embodiment, and the configuration different from the first embodiment will be mainly described.

The laser processing head 3A includes an ultrasonic wave generator 11A that generates ultrasonic waves that vibrate the processing gas. The ultrasonic generator 11A has a plurality of ultrasonic transducers 20 arranged in an annular shape. The gas filling chamber 21 is provided inside the housing 5 . In the cross section shown in FIG. 3 , the outer shape of the gas-filled chamber 21 is tapered from the end of the gas-filled chamber 21 on the side of the protective glass 8 toward the nozzle 6 . In the example shown in FIG. 3, the ultrasonic wave generator 11A is arranged at the end of the gas filling chamber 21 on the protective glass 8 side. A portion of each ultrasonic transducer 20 that generates ultrasonic waves is provided inside the gas filling chamber 21 . It should be noted that the outer shape of the gas filling chamber 21 is not limited to the shape shown in FIG. 3 and is arbitrary.

FIG. 4 is a diagram showing an example of the ultrasonic generator 11A provided in the laser processing head 3A of the laser processing apparatus 1A according to the second embodiment. A plurality of rings in which a plurality of ultrasonic transducers 20 are arranged are provided in the ultrasonic generator 11A. The center of each of the multiple rings is on the optical axis AX. In Embodiment 2, the multiple rings are concentrically arranged. It is assumed that the number of ultrasonic transducers 20 forming each ring is arbitrary. Also, the number of rings forming the ultrasonic wave generator 11A is arbitrary.

The ultrasound controller 12 controls each of the plurality of ultrasound transducers 20 . The ultrasonic control unit 12 delays the phase of the ultrasonic waves generated from each ultrasonic transducer 20 so that the phases of the ultrasonic waves from each ultrasonic transducer 20 match each other at the point of convergence. The position of the convergence point of the ultrasonic waves is set, and the timing delay amount α _i corresponding to the diameter of each ring forming the ultrasonic wave generator 11A is set according to the above equation (1). As a result, the phases of the ultrasonic waves from the ultrasonic transducers 20 are aligned at the convergence point. 3 and 4, the ultrasonic transducers 20 are arranged in each of a plurality of rings concentrically arranged around the optical axis AX. As long as the timing delay amount α _i is set, the configuration of the ultrasonic generator 11A is not limited to one in which the ultrasonic transducers 20 are arranged in concentric circles.

FIG. 5 is a diagram for explaining position adjustment of the convergence point 22 of the ultrasonic waves by the laser processing apparatus 1A according to the second embodiment. In FIG. 5, the area where the ultrasonic wave propagates is represented by a dashed line. The laser processing apparatus 1A is provided with a plurality of ultrasonic transducers 20 in each ring of the ultrasonic generator 11A. The position of the convergence point 22 can be adjusted in three-dimensional directions. Thereby, the laser processing apparatus 1A can easily adjust the position of the convergence point 22 for efficiently removing the melted material. The three double-headed arrows shown in FIG. 5 represent three-dimensional directions in which the position of the convergence point 22 can be adjusted. The laser processing device 1A can adjust the position of the convergence point 22 near the processing point.

Also, the laser processing apparatus 1A can adjust the intensity distribution of the ultrasonic waves in the region including the convergence point 22 by appropriately delaying the phase of the ultrasonic waves from the ultrasonic transducers 20 . FIG. 6 is a first diagram for explaining intensity distribution adjustment of ultrasonic waves by the laser processing apparatus 1A according to the second embodiment. FIG. 7 is a second diagram for explaining intensity distribution adjustment of ultrasonic waves by the laser processing apparatus 1A according to the second embodiment. FIG. 8 is a third diagram for explaining intensity distribution adjustment of ultrasonic waves by the laser processing apparatus 1A according to the second embodiment. The intensity distribution 23 shown in FIGS. 6, 7 and 8 is the intensity distribution of the ultrasonic waves in the region including the convergence point 22, and the sound pressure of the ultrasonic waves in the plane perpendicular to the optical axis AX is constant. represents a region that is equal to or greater than The arrows in FIGS. 6, 7 and 8 indicate the direction in which machining progresses.

The intensity distribution 23 shown in FIG. 6 has a shape in which the outer edge on the advancing direction side protrudes in the advancing direction, and the outer edge on the opposite side to the advancing direction is depressed in the advancing direction. The intensity distribution 23 shown in FIG. 7 has a shape close to an ellipse. The direction of the major axis of the ellipse matches the traveling direction. The intensity distribution 23 shown in FIG. 8 has a shape obtained by rotating the shape of the intensity distribution 23 shown in FIG. 7 by 90 degrees in a plane perpendicular to the optical axis AX. The laser processing apparatus 1A can adjust the shape of the intensity distribution 23 as shown in FIGS. 6, 7, and 8 on the basis of the circular shape. The laser processing apparatus 1A can also adjust the size of the region that is the intensity distribution 23 .

The laser processing apparatus 1A can adjust the shape of the intensity distribution 23 according to the material or plate thickness of the work 4. The laser processing apparatus 1A can easily adjust the intensity distribution 23 for efficiently removing the melt. Note that the shape of the intensity distribution 23 shown in FIGS. 6, 7 and 8 is an example. The laser processing apparatus 1A may adjust the shape of the intensity distribution 23 to a shape different from the shapes shown in FIGS.

Further, the laser processing apparatus 1A may reduce the intensity distribution 23 and move the convergence point 22 at high speed within a plane perpendicular to the optical axis AX. FIG. 9 is a diagram for explaining an example in which the laser processing apparatus 1A according to the second embodiment reduces the intensity distribution 23 and moves the convergence point 22 at high speed. FIG. 9 shows the workpiece 4 being cut by the laser beam L viewed from the laser processing head 3A side. FIG. 9 shows a machined groove 25 formed in the workpiece 4 by machining, and a convergence point 22 and a spot 24 during machining. A spot 24 is a spot of the laser light L on a plane perpendicular to the optical axis AX. In FIG. 9, it is assumed that the center point of the intensity distribution 23 is the convergence point 22 .

　In the description of FIG. 9, the upward direction and the left direction refer to the upward direction and the left direction in FIG. In the example shown in FIG. 9, it is assumed that the laser processing apparatus 1A cuts the workpiece 4 upward, then changes the processing direction leftward, and cuts leftward. The intensity distribution 23 has a circular shape that is slightly smaller than the spot 24 when the cutting process proceeds linearly upward and when the cutting process proceeds leftward in FIG. When the processing point reaches a corner where the direction of progress of processing changes from upward to leftward, the laser processing apparatus 1A reduces the intensity distribution 23 before processing reaches the corner. Furthermore, the laser processing apparatus 1A reciprocates the convergence point 22 at high speed within a plane perpendicular to the optical axis AX. In the example shown in FIG. 9, the laser processing apparatus 1A reciprocates the convergence point 22 in the directions of the double arrows shown in FIG. FIG. 9 shows how one convergence point 22 at a corner is reciprocated in an oblique direction. Thereafter, the laser processing apparatus 1A stops reciprocating movement of the convergence point 22 and returns the intensity distribution 23 to its original size.

It may be difficult to process the corners into a right-angled shape due to the occurrence of roundness according to the shape of the spot 24 or the influence of heat accumulation. For this reason, the processing quality tends to deteriorate at the corners. The laser processing apparatus 1A shapes the corner so as to form a right angle by reciprocating the convergence point 22 at the corner at high speed. Thus, the laser processing apparatus 1A can improve the processing quality by reducing the intensity distribution 23 and reciprocating the convergence point 22 within the plane perpendicular to the optical axis AX. The laser processing apparatus 1A can easily change the magnitude of the intensity distribution 23 and easily move the convergence point 22 at high speed by controlling each of the plurality of ultrasonic transducers 20 .

Here, the convergence of ultrasonic waves will be described. w is the diameter of the area including the convergence point 22 of the ultrasound, that is, the area of the intensity distribution 23, λ is the wavelength of the ultrasound, r is the distance between the ultrasound transducer 20 and the convergence point 22, and the number of the ultrasound transducers 20 is N, and the diameter of the surface of the ultrasonic transducer 20 that generates ultrasonic vibration is d, the following equation (2) holds.
w=2λr/Nd (2)

For example, for 40 kHz ultrasound, w=20 mm when λ=8.5 mm, r=200 mm, N=17, and d=10 mm.

In the case of perpendicular incidence of plane waves, P (Pa) is the acoustic radiation pressure generated on the surface of the object, E (J/m ³ ) is the acoustic energy density of the ultrasonic wave, I (W/m ² ) is the acoustic intensity, and I (W/m 2 ) is the sound velocity. Assuming c (m/s), p (Pa) as the effective value of the ultrasonic sound pressure, and ρ (kg/m ³ ) as the density of the medium, the following equation (3) holds. Note that α is a coefficient determined by the state of reflection, absorption, or transmission on the surface of the object. For total internal reflection, α=2.
P=αE=α(I/c)=α(p ² /ρc ² ) (3)

The above formula (3) indicates that an arbitrary radiation pressure pattern with an acoustic radiation pressure of P can be generated by controlling the spatio-temporal pattern of ultrasonic waves with an effective sound pressure of p.

According to the second embodiment, the laser processing apparatus 1A is provided with a plurality of ultrasonic transducers 20 in the ultrasonic generator 11A, thereby adjusting the position of the convergence point 22 and adjusting the shape or size of the intensity distribution 23. and high-speed movement of the convergence point 22 can be easily performed.

In the examples shown in FIGS. 3 and 4, each ultrasonic transducer 20 is arranged such that the normal to the surface of the ultrasonic transducer 20 that generates ultrasonic vibration is parallel to the optical axis AX. Yes, but not limited to this. Each ultrasonic transducer 20 may be arranged such that the normal to the surface that generates ultrasonic vibrations is oblique to the optical axis AX. The direction of the normal line is the direction in which the intensity of ultrasonic vibration is the strongest. The laser processing apparatus 1A can efficiently propagate the acoustic radiation pressure to the convergence point 22 by appropriately adjusting the orientation of each ultrasonic transducer 20 .

Embodiment 3.
FIG. 10 is a diagram showing a configuration example of a laser processing apparatus 1B according to the third embodiment. The laser processing apparatus 1B includes a laser processing head 3B having a configuration different from that of the laser processing head 3 shown in FIG. In the third embodiment, the same reference numerals are assigned to the same constituent elements as in the first or second embodiment, and the configuration different from that in the first or second embodiment will be mainly described.

The laser processing head 3B includes an ultrasonic wave generator 11B that generates ultrasonic waves that vibrate the processing gas. In the example shown in FIG. 10, the ultrasonic generator 11B is arranged on the surface between the end of the gas filling chamber 21 on the protective glass 8 side and the nozzle 6. In the example shown in FIG. A plurality of rings in which a plurality of ultrasonic transducers 20 are arranged are provided in the ultrasonic generator 11B. The respective rings are arranged with their positions shifted from each other in the optical axis direction. The center of each of the multiple rings is on the optical axis AX. As described above, in Embodiment 3, the plurality of rings are arranged concentrically, and are arranged in multiple stages so that the positions in the optical axis direction are shifted for each ring. It is assumed that the number of ultrasonic transducers 20 forming each ring is arbitrary. Also, the number of rings forming the ultrasonic wave generator 11B is arbitrary.

A portion of each ultrasonic transducer 20 that generates ultrasonic waves is provided inside the gas filling chamber 21 . A portion of each ultrasonic transducer 20 that generates ultrasonic waves is directed toward the protective glass 8 . The ultrasonic waves generated by each ultrasonic transducer 20 are reflected by the protective glass 8 and travel toward the workpiece 4 . The orientation of each ultrasonic transducer 20 is set so that the ultrasonic waves reflected by the protective glass 8 converge on the workpiece 4 . With such a configuration, the laser processing head 3B causes the protective glass 8 to reflect the ultrasonic waves generated by the ultrasonic wave generator 11B, and converges the ultrasonic waves on the workpiece 4. As shown in FIG.

The ultrasonic waves generated by the plurality of ultrasonic transducers 20 may include ultrasonic waves reflected by reflecting surfaces other than the protective glass 8 . In addition, in the example shown in FIG. 10, each ultrasonic transducer 20 is arranged so as to cause ultrasonic waves to travel in a direction oblique to the optical axis AX, but this is not restrictive. Each ultrasonic transducer 20 may be arranged to propagate ultrasonic waves in the direction of the optical axis AX.

The ultrasound controller 12 controls each of the plurality of ultrasound transducers 20 . The ultrasonic control unit 12 delays the phase of the ultrasonic waves generated from each ultrasonic transducer 20 so that the phases of the ultrasonic waves from each ultrasonic transducer 20 match each other at the convergence point 22 . The timing delay amount α _i corresponding to the difference in the distance between each ultrasonic transducer 20 and the convergence point 22 so that the phases of the ultrasonic waves from each ultrasonic transducer 20 match each other at the convergence point 22 is expressed by the above equation. (1). As a result, the phases of the ultrasonic waves from the ultrasonic transducers 20 are aligned at the convergence point 22 .

According to Embodiment 3, the laser processing head 3B arranges more ultrasonic transducers 20 in the gas filling chamber 21 than in the case of arranging the plurality of ultrasonic transducers 20 in the direction perpendicular to the optical axis AX. becomes possible. The laser processing apparatus 1B can increase the acoustic radiation pressure applied to the melt by arranging many ultrasonic transducers 20 . As a result, the laser processing apparatus 1B can efficiently remove the molten material generated by the melting of the work 4. As shown in FIG.

Embodiment 4.
Embodiment 4 describes an example of adjusting the position of the convergence point 22 in the direction of the optical axis AX by using a laser processing apparatus 1A similar to that of Embodiment 2. FIG. FIG. 11 is a diagram for explaining position adjustment of the convergence point 22 of the ultrasonic waves by the laser processing apparatus 1A according to the fourth embodiment. In the fourth embodiment, the same reference numerals are assigned to the same components as in the first to third embodiments, and the configuration different from the first to third embodiments will be mainly described. FIG. 11 shows the focal point 26 of the laser beam L, the convergence point 22 of the ultrasonic wave, and the outer shape of the work 4 in the groove formed in the work 4 . In FIG. 11, the area where the ultrasonic wave propagates is represented by a dashed line.

The convergence point 22 is at a different position from the focal point 26 in the direction of the optical axis AX. Further, as shown in FIG. 11, the distance between the nozzle 6 and the convergence point 22 is longer than the distance between the nozzle 6 and the focal point 26 of the laser beam L. As shown in FIG. That is, the ultrasonic wave control unit 12 converges the ultrasonic waves at the convergence point 22 at a position further advanced from the focal point 26 in the direction in which the laser light L propagates.

The laser processing device 1A may move the convergence point 22 in the direction of the optical axis AX. FIG. 12 is a diagram for explaining an example in which the laser processing apparatus 1A according to the fourth embodiment moves the convergence point 22 in the direction of the optical axis AX. In FIG. 12, the dashed line represents the region in which the ultrasonic waves are propagating. 1 A of laser processing apparatuses reciprocate the convergence point 22 between two points which are mutually different positions in the direction of the optical axis AX. One of the two points is at the same position as the convergence point 22 shown in FIG. The other of the two points is the position on the nozzle 6 side with respect to the focal point 26 . FIG. 12 shows how one convergence point 22 is reciprocated in the direction of the optical axis AX indicated by the double arrow.

FIG. 13 is a first graph for explaining the effect of making the distance between the nozzle 6 and the convergence point 22 longer than the distance between the nozzle 6 and the focal point 26 of the laser beam L in the fourth embodiment. is a diagram. FIG. 14 is a second diagram for explaining the effect of making the distance between the nozzle 6 and the convergence point 22 longer than the distance between the nozzle 6 and the focal point 26 of the laser beam L in the fourth embodiment. is a diagram. FIGS. 13 and 14 show the work 4 obtained by cutting the portion of the work 4 in which the machined groove 30 is formed. In FIG. 14, the area in which the ultrasonic wave propagates is represented by a dashed line.

FIG. 13 shows an example in which the width of the end portion 32 of the processed groove 30 on the side opposite to the nozzle 6 is narrower than the width of the end portion 31 of the processed groove 30 on the nozzle 6 side. As shown in FIG. 13, the focal point 26 is a position near the center of the thickness of the workpiece 4 . The narrower the width of the end portion 32, the more difficult it is for the molten material to be discharged from the processing groove 30, resulting in a decrease in the processing speed. If the focal point 26 is shifted toward the end portion 32 in order to widen the end portion 32, the density of the heat energy input to the portion of the work 4 on the nozzle 6 side is reduced. Also in this case, the processing speed decreases due to the decrease in the density of input heat energy.

FIG. 14 shows an example in which the convergence point 22 is set at a position further advanced from the focal point 26 in the direction in which the laser light L propagates. In the example shown in FIG. 14, the convergence point 22 is set near the edge 32 .

FIG. 15 is a third diagram for explaining the effect of making the distance between the nozzle 6 and the convergence point 22 longer than the distance between the nozzle 6 and the focal point 26 of the laser beam L in the fourth embodiment. is a diagram. FIG. 15 shows a cut plane perpendicular to the cut plane shown in FIG. 14 in the workpiece 4 shown in FIG. As shown in FIG. 15, melt 33 is deposited on the walls of working groove 30 . Convergence point 22 is a location on melt 33 near edge 32 .

By setting the convergence point 22 near the end portion 32 as shown in FIGS. 14 and 15, the discharge of the molten material 33 from the end portion 32 is facilitated, and the width of the end portion 32 can be widened. The increased width of the end portion 32 enables efficient removal of the melt 33 from the machined groove 30 . Thereby, the laser processing apparatus 1A can improve the processing speed.

The laser processing apparatus 1A may reciprocate the convergence point 22 as shown in FIG. The ultrasonic wave propagates at a speed of sound of 340 m/s, while the cutting speed is about 0.01 m/s to 2 m/s, and the flow speed of the melt 33 is about 10 m/s. Since the speed of sound is sufficiently higher than the processing speed and the flow speed of the melt 33, the acoustic radiation pressure at the convergence point 22 can be maintained even if the convergence point 22 is reciprocated. Therefore, the laser processing apparatus 1A can apply acoustic radiation pressure over a wide range of the processed groove 30 while maintaining the acoustic radiation pressure at the convergence point 22 . Thereby, the laser processing apparatus 1A can further promote the removal of the melted material 33 . In addition, the laser processing apparatus 1A can reduce the unevenness of the cutting front of the workpiece 4, thereby enabling high-quality processing.

Thus, according to Embodiment 4, the laser processing apparatus 1A has a longer distance between the nozzle 6 and the convergence point 22 than the distance between the nozzle 6 and the focal point 26, so that the molten material 33 can be efficiently removed. Note that the position adjustment of the convergence point 22 described in the fourth embodiment may be performed by the laser processing apparatus 1B similar to that of the third embodiment.

Embodiment 5.
Embodiment 5 describes a configuration in which a gas rectifying section is combined with the laser processing heads 3, 3A, and 3B of Embodiments 1 to 4. FIG. Here, a configuration in which the laser processing head 3A of the second embodiment is combined with a gas rectifying section will be described as an example. The gas rectifying section described in Embodiment 5 can also be combined with the laser processing heads 3 and 3B in the same manner as the laser processing head 3A. In Embodiment 5, the same components as those in Embodiments 1 to 4 are denoted by the same reference numerals, and configurations different from those in Embodiments 1 to 4 will be mainly described.

FIG. 16 is a diagram showing a portion of the laser processing head 3A according to Embodiment 5, which includes the gas rectifying section 40. As shown in FIG. The gas rectifying section 40 is a component through which the processing gas passes before flowing into the gas charging chamber 21 shown in FIG. 3 to regulate the flow of the processing gas. The gas rectifying section 40 is provided in the vicinity of the portion of the tube 9 connected to the housing 5 .

A partially unstable flow such as turbulence may occur in the flow of the processing gas inside the tube 9 . By changing the flow of the processing gas in the gas straightening section 40 , the density distribution of the processing gas can be made uniform compared to before passing through the gas straightening section 40 . The laser processing head 3</b>A can align the phases of the ultrasonic waves at the convergence point 22 by allowing the processing gas having a uniform density distribution to flow into the gas-filled chamber 21 . The laser processing head 3A can efficiently apply the acoustic radiation pressure to the melted material by aligning the phases of the ultrasonic waves, and can efficiently remove the melted material. As described above, according to Embodiment 5, the laser processing head 3A can efficiently remove the molten material by including the gas rectifying section 40 .

Next, a hardware configuration for realizing the ultrasound control unit 12 in Embodiments 1 to 5 will be described. The ultrasonic controller 12 is implemented by a processing circuit. The processing circuitry may be circuitry in which a processor executes software, or it may be dedicated circuitry.

FIG. 17 is a diagram showing a first configuration example of hardware that implements the ultrasound control unit 12 according to Embodiments 1 to 5. As shown in FIG. A first configuration example is a configuration example in which the functions of the ultrasound control unit 12 are realized by a processing circuit 50 having a processor 51 and a memory 52 . The functions of the ultrasound controller 12 are realized by the processor 51 reading and executing a program stored in the memory 52 .

The processor 51 is a CPU (Central Processing Unit, also referred to as a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, or DSP (Digital Signal Processor)). The memory 52 is a non-volatile memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (registered trademark) (Electrically Erasable Programmable Read Only Memory), etc. Alternatively, a volatile semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), or the like.

The input/output circuit 53 is a circuit that receives an input signal to the processing circuit 50 from the outside and outputs a signal generated by the processing circuit 50 to the outside of the processing circuit 50 . The input/output circuit 53 outputs the control signal generated by the processing circuit 50 to the

ultrasonic generators

11, 11A and 11B.

The ultrasound control unit 12 may be realized by dedicated hardware. FIG. 18 is a diagram showing a second configuration example of hardware that implements the ultrasound control unit 12 according to the first to fifth embodiments. A second configuration example is a configuration example in which the functions of the processing circuit 50 shown in FIG. 17 are realized by a processing circuit 54 that is dedicated hardware.

The processing circuit 54 is, for example, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a circuit combining these. In the example shown in FIG. 18, the ultrasound controller 12 is implemented by a single processing circuit 54, but the present invention is not limited to this. Hardware may include a plurality of processing circuits 54 , and the ultrasound control unit 12 may be realized by the plurality of processing circuits 54 . A part of the ultrasound control unit 12 may be realized by the processing circuit 50 shown in FIG. 17, and the rest may be realized by dedicated hardware similar to the processing circuit 54.

The configuration shown in each embodiment above is an example of the content of the present disclosure. The configuration of each embodiment can be combined with another known technique. Configurations of respective embodiments may be combined as appropriate. A part of the configuration of each embodiment can be omitted or changed without departing from the gist of the present disclosure.

1, 1A, 1B laser processing device, 2 laser oscillator, 3, 3A, 3B laser processing head, 4 workpiece, 5 housing, 6 nozzle, 7 processing lens, 8 protective glass, 9 tube, 10, 21 gas filling chamber, 11, 11A, 11B Ultrasonic generator, 12 Ultrasonic controller, 20 Ultrasonic oscillator, 22 Convergence point, 23 Intensity distribution, 24 Spot, 25, 30 Processing groove, 26 Focus, 31, 32 Edge, 33 Melt Object, 40 gas rectifier, 50, 54 processing circuit, 51 processor, 52 memory, 53 input/output circuit, AX optical axis, L laser light.

Claims

A laser processing head included in a laser processing apparatus that locally melts a workpiece by irradiating it with a laser beam and removes the molten material generated by the melting by injecting a processing gas,
a housing having a gas-filled chamber filled with the processing gas and containing therein a processing lens for condensing the laser beam;
a nozzle attached to the housing through which the laser beam to irradiate the work and the processing gas injected from the gas filling chamber to the work pass;
an ultrasonic generator that generates ultrasonic waves that vibrate the processing gas inside the gas filling chamber,
A laser processing head, wherein the melt is removed by the processing gas to which ultrasonic vibration is applied.
A protective glass provided inside the housing through which the laser beam passes;
2. The laser processing head according to claim 1, wherein the ultrasonic waves generated by the ultrasonic generator are reflected by the protective glass to apply ultrasonic vibrations to the processing gas.
3. The laser processing head according to claim 1 or 2, wherein the ultrasonic generator has a plurality of ultrasonic transducers for generating the ultrasonic waves.
The point at which the acoustic radiation pressure due to the ultrasonic wave is maximum is defined as the convergence point of the ultrasonic wave, and the distance between the nozzle and the convergence point of the ultrasonic wave is greater than the distance between the nozzle and the focus of the laser beam. 4. The laser processing head of claim 3, wherein the distance is longer.
5. The laser processing according to any one of claims 1 to 4, further comprising a gas rectifying section through which the processing gas passes before flowing into the gas charging chamber and for regulating the flow of the processing gas. head.
A laser processing apparatus that locally melts a workpiece by irradiating it with a laser beam and removes the molten material generated by the melting by injecting a processing gas,
a laser oscillator that outputs the laser light;
a housing provided with a gas-filled chamber filled with a processing gas for removing melted matter generated by melting of the workpiece, and containing therein a processing lens for condensing the laser beam; a nozzle mounted through which the laser beam to irradiate the work and the processing gas injected from the gas filling chamber to the work pass; a laser processing head having a sound wave generator;
and an ultrasonic wave controller that converges the ultrasonic waves on the workpiece by controlling the ultrasonic wave generator.
The ultrasonic generator has a plurality of ultrasonic transducers that generate the ultrasonic waves,
7. The laser processing apparatus according to claim 6, wherein the ultrasonic control unit controls each of the plurality of ultrasonic transducers.
With the point at which the acoustic radiation pressure due to the ultrasonic wave is maximum as the convergence point of the ultrasonic wave, the ultrasonic control unit controls the convergence point at a position further advanced from the focal point of the laser light in the direction in which the laser light propagates. 8. The laser processing apparatus according to claim 7, wherein the ultrasonic waves are converged at.
The point at which the acoustic radiation pressure due to the ultrasonic wave is maximum is defined as a convergence point of the ultrasonic wave, and the ultrasonic control unit reciprocates the convergence point in the direction of the optical axis of the processing lens. Item 8. The laser processing apparatus according to item 7.
The laser processing apparatus according to claim 7, wherein the ultrasonic wave control unit changes the intensity distribution of the ultrasonic wave in a plane perpendicular to the optical axis of the processing lens.
With the point at which the acoustic radiation pressure due to the ultrasonic wave is maximum as the convergence point of the ultrasonic wave, the ultrasonic wave control unit reduces the intensity distribution in an area including the convergence point so that a plane perpendicular to the optical axis 11. The laser processing apparatus according to claim 10, wherein the convergence point is reciprocated within.