JP2019042793A - Laser processing machine - Google Patents

Abstract

To provide a laser processing machine which can select one beam profile from multiple beam profiles, and can process sheet metal using a laser beam having the selected beam profile.SOLUTION: A convex-concave axicon lens 31 transmits a laser beam being divergent light having a Gaussian beam profile. A plano-convex axicon lens 32 transmits the laser beam emitted from the convex-concave axicon lens 31. An NC device 50 controls positions of the convex-concave axicon lens 31 and the plano-convex axicon lens 32 so that modes are switched between: a first mode in which the convex-concave axicon lens 31 and the plano-convex axicon lens 32 abut each other so as to cause a beam profile of the laser beam focused by a focusing lens 34 to be a Gaussian profile; and a second mode in which the convex-concave axicon lens 31 and the plano-convex axicon lens 32 are spaced apart from each other so as to cause the beam profile to be a ring profile.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a laser processing machine that processes a metal plate (sheet metal) with laser light.

  2. Description of the Related Art Laser processing machines that process a sheet metal by cutting or welding it with laser light emitted from a laser oscillator or marking the sheet metal have become widespread. Various laser oscillators are used in the laser processing machine. In order to cut a sheet metal having a relatively small thickness at high speed, for example, a fiber laser oscillator is often used.

Special table 2015-500571 gazette International Publication No. 2011/124671

  The laser processing machine needs to appropriately set the beam profile of the laser beam applied to the sheet metal according to the processing conditions of the sheet metal. Patent Documents 1 and 2 describe a laser processing machine that can process a sheet metal by selecting any one of a plurality of beam profiles.

  The configuration for selecting a beam profile described in Patent Documents 1 and 2 is complicated, and a laser processing machine capable of selecting a beam profile with a simple and inexpensive configuration is desired.

  An object of the present invention is to provide a laser processing machine that can process a sheet metal by selecting any one of a plurality of beam profiles with a simple and inexpensive configuration.

  The present invention has a convex-concave axicon lens that has a convex curved surface as a laser light incident surface and a concave axicon surface as a laser light emission surface and transmits a divergent laser beam having a Gaussian beam profile, A plano-convex axicon lens that has a convex axicon surface as an incident surface and a flat surface as a laser light exit surface and transmits laser light emitted from the convex-concave axicon lens, and a laser emitted from the plano-convex axicon lens A converging lens that focuses light to irradiate a sheet metal to be processed, a first moving mechanism for moving the convex / concave axicon lens in the optical axis direction, and the convex / concave axicon lens by the first moving mechanism A first drive unit for driving the lens to move in the optical axis direction, and a second moving mechanism for moving the plano-convex axicon lens in the optical axis direction A second driving unit configured to drive the plano-convex axicon lens to move in the optical axis direction by the second moving mechanism; and the convex-concave axicon lens and the plano-convex axicon lens are brought close to each other; The first mode in which the beam profile of the laser beam focused by the focusing lens is a Gaussian type, and the laser beam focused by the focusing lens by separating the convex / concave axicon lens and the plano-convex axicon lens from each other And a control device for controlling the positions of the convex-concave axicon lens and the plano-convex axicon lens so as to switch to a second mode in which the beam profile of the lens is switched to a ring type is provided. .

  The present invention also includes a convex lens that receives divergent laser light and converts it into convergent light, and a concave lens that receives convergent light laser light emitted from the convex lens, and is emitted from the convex lens. A beam diameter varying device that varies the beam diameter emitted from the concave lens according to the convergence angle of the convergent light, a first moving mechanism for moving the convex lens in the optical axis direction, and the first moving mechanism. A first driving unit that drives the convex lens to move in the optical axis direction, a second moving mechanism for moving the concave lens in the optical axis direction, and the concave lens is moved in the optical axis direction by the second moving mechanism. And a laser beam emitted from the beam diameter variable device is incident, a plane as a laser beam incident surface, and a concave axicon as a laser beam emission surface A plano-concave axicon lens having a convex axicon surface as a laser light incident surface, a convex curved surface as a laser light exit surface, and focusing the laser light emitted from the plano-concave axicon lens A biconvex axicon lens that irradiates the sheet metal, a third movement mechanism for moving the plano-concave axicon lens in the optical axis direction, and the plano-concave axicon lens by the third movement mechanism. A laser processing machine comprising: a third drive unit that is driven to move in a direction.

  According to the laser processing machine of the present invention, a sheet metal can be processed by selecting any one of a plurality of beam profiles with a simple and inexpensive configuration.

It is a figure which shows the example of a whole structure of the laser beam machine of 1st Embodiment. It is a figure which shows the detailed structural example of the collimator unit in the laser beam machine of 1st Embodiment. It is a figure for demonstrating the change of the beam profile in the laser beam machine of 1st Embodiment. It is a figure which shows a Gaussian type beam profile. It is a figure which shows a thick ring type beam profile. It is a figure which shows a sharp ring type beam profile. It is a figure which shows the beam profile in which predetermined intensity | strength exists in the center of a thick ring. It is a figure which shows the beam profile in which predetermined intensity | strength exists in the center of a sharp ring. It is a figure which shows the convex / concave axicon lens and plano-convex axicon lens used with the laser beam machine of 2nd Embodiment. It is a figure which shows the convex / concave axicon lens and plano-convex axicon lens which are used with the laser beam machine of 3rd Embodiment. It is a figure which shows the convex / concave axicon lens and plano-convex axicon lens used with the laser beam machine of 4th Embodiment. It is a figure for demonstrating the change of the beam profile in the laser beam machine of 4th Embodiment. It is a figure which shows the detailed structural example of the collimator unit in the laser beam machine of 5th Embodiment. It is a figure for demonstrating the change of the beam profile in the state which enlarged the beam diameter with the beam diameter variable apparatus in the laser beam machine of 5th Embodiment. It is a figure for demonstrating the change of the beam profile in the state which made the beam diameter small with the beam diameter variable apparatus in the laser beam machine of 5th Embodiment.

  Hereinafter, laser processing machines according to first to fifth embodiments will be described with reference to the accompanying drawings. In the laser processing machines of the first to fifth embodiments, the same reference numerals are given to portions having the same function, and the description thereof may be omitted.

<First Embodiment>
In FIG. 1, a laser beam machine 100 generates a laser beam and emits a laser oscillator 10, a laser machining unit 20, and a process fiber 12 that transmits the laser beam emitted from the laser oscillator 10 to the laser machining unit 20. With. In addition, the laser processing machine 100 includes an operation unit 40 and an NC device 50 that controls the laser oscillator 10 and the laser processing unit 20. The NC device 50 is an example of a control device.

  The laser oscillator 10 is preferably a laser oscillator that amplifies excitation light emitted from a laser diode and emits laser light having a predetermined wavelength, or a laser oscillator that directly uses laser light emitted from a laser diode. The laser oscillator 10 is, for example, a solid laser oscillator, a fiber laser oscillator, a disk laser oscillator, or a direct diode laser oscillator (DDL oscillator).

  The laser oscillator 10 emits 1 μm band laser light having a wavelength of 900 nm to 1100 nm. Taking a fiber laser oscillator and a DDL oscillator as examples, the fiber laser oscillator emits laser light with a wavelength of 1060 nm to 1080 nm, and the DDL oscillator emits laser light with a wavelength of 910 nm to 950 nm.

  The laser processing unit 20 includes a processing table 21 on which a sheet metal W to be processed is placed, a portal X-axis carriage 22, a Y-axis carriage 23, and a collimator unit 30 fixed to the Y-axis carriage 23. The X-axis carriage 22 is configured to be movable in the X-axis direction on the processing table 21. The Y-axis carriage 23 is configured to be movable in the Y-axis direction perpendicular to the X-axis on the X-axis carriage 22.

  The collimator unit 30 includes a convex / concave axicon lens 31 into which laser light indicated by a one-dot chain line emitted from the exit end of the process fiber 12 is incident, and a plano-convex axicon lens into which laser light emitted from the convex / concave axicon lens 31 is incident. 32. The collimator unit 30 also reflects the laser light emitted from the plano-convex axicon lens 32 downward in the Z-axis direction perpendicular to the X-axis and the Y-axis, and the laser light reflected by the bend mirror 33. A focusing lens 34 for focusing and a processing head 35 are provided.

  The laser processing machine 100 configured as described above processes the sheet metal W with the laser light emitted from the laser oscillator 10. The processing of the sheet metal W may be either cutting or welding of the sheet metal W or marking on the sheet metal W.

  A detailed configuration example of the collimator unit 30 will be described with reference to FIG. In FIG. 2, divergent laser light indicated by a one-dot chain line emitted from the emission end 12 e of the process fiber 12 is incident on the convex / concave axicon lens 31. The convex / concave axicon lens 31 is a concave axicon surface in which the laser light incident surface 31a1 is a convex curved surface and the laser light emission surface 31b1 is a concave conical surface. The curvature of the exit surface 31b1 is zero.

  The convex / concave axicon lens 31 is attached to a moving mechanism 311 for making the convex / concave axicon lens 31 movable in the optical axis direction. When the driving unit 312 drives the moving mechanism 311, the convex / concave axicon lens 31 moves in the optical axis direction as indicated by an arrow.

  The laser beam emitted from the exit surface 31 b 1 of the convex / concave axicon lens 31 is incident on the plano-convex axicon lens 32. The planoconvex axicon lens 32 has a convex axicon surface in which the laser light incident surface 32a1 is a convex conical surface and a laser light exit surface 32b1 in a flat surface. The curvature of the incident surface 32a1 is zero.

  The plano-convex axicon lens 32 is attached to a moving mechanism 321 for making the plano-convex axicon lens 32 movable in the optical axis direction. When the drive unit 322 drives the moving mechanism 321, the plano-convex axicon lens 32 moves in the optical axis direction as indicated by an arrow.

  The moving mechanisms 311 and 321 may be any one of gears, belts, rack and pinions, worm gears, ball screws, or the like (or any combination thereof), and the driving units 312 and 312 are, for example, motors. The NC device 50 controls the driving unit 312 to move the convex / concave axicon lens 31 and controls the driving unit 322 to move the plano-convex axicon lens 32. The drive units 312 and 322 may be controlled by a control device other than the NC device 50.

  The entrance surface 31a1 of the convex / concave axicon lens 31 is set to a curvature that converts divergent light into parallel light when the distance from the exit end 12e to the surface of the entrance surface 31a1 is d1. The exit surface 31b1 of the convex / concave axicon lens 31 converts parallel light into divergent light. The divergent light is incident on the incident surface 32 a 1 of the plano-convex axicon lens 32. The angles of the exit surface 31b1 and the entrance surface 32a1 with respect to the optical axis are set so as to convert divergent light into parallel light by the refraction action of both.

  Since the emission surface 32b1 is a flat surface, parallel light is incident on the bend mirror 33. The parallel light whose optical axis is bent 90 degrees by the bend mirror 33 is focused by the focusing lens 34 so that the focal position is at or near the surface of the sheet metal W, and is irradiated onto the sheet metal W.

  Since the collimator unit 30 is freely movable in the X-axis direction and the Y-axis direction by the X-axis carriage 22 and the Y-axis carriage 23, the position at which the laser beam emitted from the processing head 35 is applied to the sheet metal W is set to the X-axis. It can be arbitrarily moved in the direction and the Y-axis direction.

  Although not shown in FIG. 2, the focusing lens 34 may be configured to be movable in the optical axis direction so that the focal position of the laser light irradiated onto the sheet metal W can be varied. In this case, a moving mechanism and a driving unit for moving the focusing lens 34 may be provided.

  As described above, the laser beam machine 100 according to the first embodiment includes the convex / concave axicon lens 31 and the plano-convex axicon lens 32, and the convex / concave axicon lens 31 and the plano-convex axicon lens 32 are movable in the optical axis direction. It is configured. Therefore, as will be described later, according to the laser processing machine 100 of the first embodiment, the beam profile of the laser light irradiated onto the sheet metal W can be selected from a plurality of beam profiles. The laser beam machine 100 according to the first embodiment can process the sheet metal W using the selected beam profile.

  With reference to FIG. 3, how the beam profile changes in accordance with the positions of the convex / concave axicon lens 31 and the plano-convex axicon lens 32 in the laser processing machine 100 of the first embodiment will be described. FIG. 3 conceptually shows a state in which the bend mirror 33 is omitted and the convex / concave axicon lens 31, the plano-convex axicon lens 32, and the focusing lens 34 are arranged so that the optical axis is in a straight line. In FIG. 3, Li indicates an inner beam in the light beam, and Lo indicates an outer beam in the light beam.

  The laser beam emitted from the emission end 12e has a Gaussian beam profile as shown in FIG. 4A. The beam profile is a characteristic (shape) indicating an intensity distribution when the laser beam is viewed in a cross section. The Gaussian beam profile has a characteristic that the intensity increases steeply from the peripheral part toward the central part.

  FIG. 3A shows a state in which the plano-convex axicon lens 32 is moved so as to be close to the convex-concave axicon lens 31. The beam collimated by the convex-concave axicon lens 31 is collimated at substantially the same position inside the plano-convex axicon lens 32 (it proceeds as it is as parallel light). The convex-concave axicon lens 31 and the plano-convex axicon lens 32 that are close to each other function substantially the same as the plano-convex lens. Therefore, the beam profile of the laser beam focused by the focusing lens 34 having a predetermined focal length is a Gaussian type as shown in FIG. 4A.

  FIG. 3B shows a state in which only the plano-convex axicon lens 32 is moved away from the convex-concave axicon lens 31 from the state of FIG. In FIG. 3B, a region where no beam exists is generated further inside the inner beam Li, and the collimated beam propagating from the plano-convex axicon lens 32 to the focusing lens 34 is like a thick ring. It becomes a state. The beam profile of the laser beam focused by the focusing lens 34 is a Gaussian type at the focusing point, and a thick ring type as shown in FIG. 4B on the near side and the back side (the left side and the right side in FIG. 3).

  FIG. 3C shows a state in which the convex / concave axicon lens 31 and the plano-convex axicon lens 32 are moved from the state of FIG. 3B to the exit end 12e side by the same distance. . At this time, the inner beam Li and the outer beam Lo that pass through the convex-concave axicon lens 31 and the plano-convex axicon lens 32 are each divergent light, and the divergence angle of the beam Lo is larger than the divergence angle of the beam Li.

  When the focusing lens 34 focuses the beams Li and Lo, the beam Lo is focused to the back side (right side in FIG. 3) from the beam Li, so that the focusing point moves to the back side. The beam profile of the laser beam focused by the focusing lens 34 has a sharp ring shape as shown in FIG. 4C on the back side from the focusing point. Note that the beam profile having a sharper peak at the center than the Gaussian type shown in FIG.

  FIG. 3D shows a state in which the convex-concave axicon lens 31 and the plano-convex axicon lens 32 are moved from the state of FIG. 3B by the same distance to the focusing lens 34 side. . At this time, the inner beam Li and the outer beam Lo that pass through the convex-concave axicon lens 31 and the plano-convex axicon lens 32 respectively become convergent light, and the convergence angle of the beam Lo is larger than the convergence angle of the beam Li.

  When the focusing lens 34 focuses the beams Li and Lo, the beam Lo is focused to the near side with respect to the beam Li, so that the focusing point moves to the near side. The beam profile of the laser beam focused by the focusing lens 34 has a sharp ring shape as shown in FIG. 4C on the front side of the focusing point. Note that the beam profile has a sharp peak at the center at the focal point and the back side of the focal point.

  As shown in FIG. 3A, a mode in which the convex / concave axicon lens 31 and the plano-convex axicon lens 32 are brought close to each other and the beam profile is a Gaussian type is defined as a first mode. As shown in FIG. 3C or 3D, the mode in which the convex / concave axicon lens 31 and the plano-convex axicon lens 32 are separated from each other and the beam profile is a ring type is defined as a second mode. The NC device 50 can switch between the first mode and the second mode.

  In the first mode, if the distance from the exit end 12e to the entrance surface 31a1 of the convex / concave axicon lens 31 is the first distance, the distance from the exit end 12e to the entrance surface 31a1 is the first distance in the second mode. The second distance is different from the distance.

  In the laser beam machine 100 of the first embodiment, the curvature of the entrance surface 31a1 of the convex / concave axicon lens 31 is set so that the distance d1 is 120 mm, the angle of the concave axicon surface of the exit surface 31b1 and the plano-convex axicon lens It is assumed that the angle of the convex axicon surface of the incident surface 32a1 at 32 is set to 9 degrees. The convex / concave axicon lens 31 is moved 5 mm from the state shown in FIG. 3A toward the exit end 12e, and the distance between the convex / concave axicon lens 31 and the plano-convex axicon lens 32 is 40 mm, as shown in FIG. Suppose that it is in a state. As a result, a ring-shaped beam profile having a diameter of about 400 μm is formed on the back side of the focusing point.

Second Embodiment
The laser beam machine 100 of the second embodiment has a configuration in which the convex / concave axicon lens 31 in FIG. 1 is replaced with a convex / concave axicon lens 31B shown in FIG.

  In FIG. 5, the convex / concave axicon lens 31B has an incident surface 31a2 as a convex curved surface and an exit surface 31b2 as a concave axicon surface. The curvature of the incident surface 31a2 is smaller than the curvature of the incident surface 31a1 of the convex / concave axicon lens 31 indicated by a two-dot chain line.

  The convex / concave axicon lens 31B compensates for the amount of curvature of the incident surface 31a2 smaller than the curvature of the incident surface 31a1 by giving a predetermined convex curvature to the exit surface 31b2, and is similar to the convex / concave axicon lens 31. It is comprised so that there may exist an effect | action. In order to compare the exit surface 31b1 and the exit surface 31b2, the exit surface 31b1 is indicated by a two-dot chain line.

<Third Embodiment>
The laser beam machine 100 according to the third embodiment has a configuration in which the convex / concave axicon lens 31 and the plano-convex axicon lens 32 in FIG. 1 are respectively replaced with the convex / concave axicon lens 31C and the plano-convex axicon lens 32C shown in FIG. .

  In FIG. 6, the convex / concave axicon lens 31C has an incident surface 31a2 as a convex curved surface and an exit surface 31b1 as a concave axicon surface. The curvature of the incident surface 31a2 is smaller than the curvature of the incident surface 31a1 of the convex / concave axicon lens 31 indicated by a two-dot chain line.

  In the plano-convex axicon lens 32C, the incident surface 32a2 is a convex axicon surface, and the exit surface 32b1 is a flat surface. The amount by which the curvature of the incident surface 31a2 in the convex / concave axicon lens 31C is made smaller than the curvature of the incident surface 31a1 is compensated by giving a predetermined convex curvature to the incident surface 32a2 of the plano-convex axicon lens 32C.

  Thus, the convex / concave axicon lens 31C and the plano-convex axicon lens 32C are configured to perform the same operation as the convex / concave axicon lens 31 and the plano-convex axicon lens 32. In order to compare the incident surface 31a1 and the incident surface 31a2, the incident surface 31a1 is indicated by a two-dot chain line.

<Fourth embodiment>
The laser beam machine 100 of the fourth embodiment has a configuration in which the convex / concave axicon lens 31 and the plano-convex axicon lens 32 in FIG. 1 are replaced with the convex / concave axicon lens 31D and the plano-convex axicon lens 32D shown in FIG. 7, respectively. .

  As shown in FIG. 7, in the convex / concave axicon lens 31D, the central portion of the exit surface 31b3 that is a concave axicon surface is a flat surface 31b4, and the plano-convex axicon lens 32D is the central portion of the entrance surface 32a3 that is a convex axicon surface. Is a plane 32a4.

  With reference to FIG. 8, in the laser beam machine 100 of the fourth embodiment, how the beam profile changes according to the positions of the convex / concave axicon lens 31D and the plano-convex axicon lens 32D will be described. FIG. 8 also conceptually shows a state in which the bend mirror 33 is omitted and the convex / concave axicon lens 31D, plano-convex axicon lens 32D, and focusing lens 34 are arranged so that the optical axis is in a straight line. In FIG. 8, Li represents an inner beam, Lo represents an outer beam, and Lc represents a central beam passing through the planes 31b4 and 32a4.

  The action of the convex / concave axicon lens 31D and the plano-convex axicon lens 32D on the inner beam Li and the outer beam Lo is the same as the action of the convex / concave axicon lens 31 and plano-convex axicon lens 32. Therefore, the operation due to the presence of the center-side beam Lc will be described.

  FIG. 8A shows a state in which the plano-convex axicon lens 32D is moved so as to approach the convex-concave axicon lens 31D. 8A is the same as FIG. 3A, and the beam profile of the laser beam focused by the focusing lens 34 is a Gaussian type as shown in FIG. 4A.

  FIG. 8B shows a state in which only the plano-convex axicon lens 32D is moved away from the convex-concave axicon lens 31D from the state of FIG. In FIG. 8B, since the center side beam Lc passing through the planes 31b4 and 32a4 exists inside the inner beam Li, on the near side and the far side (left side and right side in FIG. 8) of the focal point. As shown in FIG. 4D, the beam profile has a predetermined intensity at the center of the thick ring.

  FIG. 8C shows a state in which the convex / concave axicon lens 31D and the plano-convex axicon lens 32D are moved to the exit end 12e side by the same distance from the state of FIG. 8B. . Behind the focusing point, as shown in FIG. 4E, the beam profile has a predetermined intensity at the center of a sharp ring.

  FIG. 8D shows a state in which the convex / concave axicon lens 31D and the plano-convex axicon lens 32D are moved to the focusing lens 34 side by the same distance from the state of FIG. 8B. . On the near side of the focal point, the beam profile shown in FIG. 4E is obtained.

  In the laser beam machine 100 according to the first embodiment, if the ring diameter of the ring beam profile is increased, the energy at the center of the ring may be insufficient. According to the laser beam machine 100 of the fourth embodiment, the energy at the center of the ring can be supplemented.

<Fifth Embodiment>
In the collimator unit 30 shown in FIG. 9, the convex / concave axicon lens 31 and the plano-convex axicon lens 32 in the collimator unit 30 shown in FIG. 2 are replaced with a convex lens 36 and a concave lens 37, respectively. The convex lens 36 is a biconvex lens having a positive focal length, and the concave lens 37 is a biconcave lens having a negative focal length.

  In the collimator unit 30 shown in FIG. 9, the converging lens 34 is replaced with a planoconcave axicon lens 38 and a biconvex axicon lens 39. The laser beam machine 100 according to the fifth embodiment has the above-described configuration.

  The convex lens 36 is attached to a moving mechanism 361 for making the convex lens 36 movable in the optical axis direction. When the driving unit 362 drives the moving mechanism 361, the convex lens 36 moves in the optical axis direction as indicated by an arrow. The concave lens 37 is attached to a moving mechanism 371 for making the concave lens 37 movable in the optical axis direction. When the drive unit 372 drives the moving mechanism 371, the concave lens 37 moves in the optical axis direction as indicated by an arrow.

  As will be described later, the convex lens 36 and the concave lens 37 constitute a beam diameter varying device 367 that varies the beam diameter D.

  The plano-concave axicon lens 38 is a concave axicon surface in which the laser light incident surface 38a is a flat surface and the laser light exit surface 38b is a concave conical surface. The curvature of the exit surface 38b is zero. In the biconvex axicon lens 39, the laser light incident surface 39a is a convex axicon surface, and the laser light exit surface 39b is a convex curved surface. The curvature of the incident surface 39a is zero.

  The plano-concave axicon lens 38 is attached to a moving mechanism 381 for making the plano-concave axicon lens 38 movable in the optical axis direction. When the driving unit 382 drives the moving mechanism 381, the plano-concave axicon lens 38 moves in the optical axis direction as indicated by an arrow.

  The moving mechanisms 361, 371, and 381 may be similar to the moving mechanisms 311 and 321. The driving units 362, 372, and 382 are, for example, motors. The NC device 50 controls the drive units 362, 372, and 382 to move the convex lens 36, the concave lens 37, and the plano-concave axicon lens 38, respectively.

  In FIG. 9, the convex lens 36 is arranged such that the distance from the exit end 12 e to the convex lens 36 is equal to or greater than the focal length of the convex lens 36. Therefore, the convex lens 36 converts the divergent light of the laser light into convergent light. The NC device 50 can move the convex lens 36 in the optical axis direction under the condition that the distance from the exit end 12e to the convex lens 36 is equal to or greater than the focal length of the convex lens 36.

  If the concave lens 37 does not exist, the convergent light emitted from the convex lens 36 converges at a predetermined position as a focal point. If the concave lens 37 is arranged on the convex lens 36 side from the focal point at a position (reference position) shifted by the same distance as the focal length of the concave lens 37, the concave lens 37 converts the convergent light into parallel light. If the concave lens 37 is arranged on the convex lens 36 side from the focusing point at a position shifted by a distance longer than the focal length of the concave lens 37, the concave lens 37 converts the convergent light into divergent light.

  The beam diameter D of the laser light emitted from the concave lens 37 changes according to the convergence angle of the convergent light emitted from the convex lens 36. The beam diameter varying device 367 can vary the beam diameter D.

  How the beam diameter D and the beam profile change in the laser beam machine 100 according to the fifth embodiment will be described with reference to FIGS. 10A and 10B. 10A and 10B, the bend mirror 33 is omitted, and a concept is shown in which a convex lens 36, a concave lens 37, a plano-concave axicon lens 38, and a biconvex axicon lens 39 are arranged so that the optical axis is in a straight line. Is shown.

  FIGS. 10A and 10B show a state where the distance between the convex lens 36 and the concave lens 37 is short, the concave lens 37 is at the reference position with respect to the convex lens 36, and the concave lens 37 emits parallel light. Yes. At this time, since the convergence angle of the convergent light emitted from the convex lens 36 is large, the beam diameter D increases.

  FIG. 10A shows a state in which the plano-concave axicon lens 38 is moved so as to be close to the biconvex axicon lens 39. The plano-concave axicon lens 38 and the biconvex axicon lens 39 that are close to each other function in substantially the same manner as a plano-convex focusing lens. Therefore, the beam profile of the laser beam focused by the plano-concave axicon lens 38 and the biconvex axicon lens 39 is a Gaussian type as shown in FIG. 4A.

  FIG. 10A (b) shows a state in which only the plano-concave axicon lens 38 is moved away from the biconvex axicon lens 39 from the state of FIG. 10A (a). The beam profile of the laser beam focused by the biconvex axicon lens 39 is a Gaussian type at the focusing point, and a thick ring type as shown in FIG. 4B on the front side and the back side (the left side and the right side in FIG. 10A). It becomes.

  (C) of FIG. 10A has shown the state which moved the concave lens 37 to the convex lens 36 side from the state of (b) of FIG. 10A. The concave lens 37 emits divergent light. At this time, the beam profile of the laser beam focused by the biconvex axicon lens 39 has a sharp ring shape as shown in FIG. In FIGS. 10A and 10B, the Rayleigh length is relatively short.

  10B (a) and (b), the convex lens 36 is moved to the exit end 12e side so that the distance between the convex lens 36 and the concave lens 37 is longer than that in FIGS. 10A (a) and (b). Indicates the state. The concave lens 37 is at the reference position with respect to the convex lens 36, and the concave lens 37 emits parallel light. At this time, since the convergence angle of the convergent light emitted from the convex lens 36 is smaller than that in (a) and (b) of FIG. 10A, the beam diameter D becomes smaller.

  In FIG. 10B (a), similarly to the case of FIG. 10A (a), the beam profile of the focused laser beam is a Gaussian type. However, the focusing diameter in FIG. 10B (a) is smaller than that in FIG. 10A (a). The same applies to (b) and (c) of FIG. 10B.

  FIG. 10B (b) shows a state in which only the plano-concave axicon lens 38 is moved away from the biconvex axicon lens 39 from the state of FIG. 10B (a). The beam profile in (b) of FIG. 10B is the same as (b) of FIG. 10A.

  FIG. 10B (c) shows a state in which the concave lens 37 is moved to the convex lens 36 side from the state of FIG. 10B (b). The concave lens 37 emits divergent light. The beam profile in (c) of FIG. 10B is the same as (c) of FIG. 10A. In FIGS. 10B (b) and (c), the Rayleigh length is longer than that in FIGS. 10A (b) and (c).

  As described above, according to the laser beam machine 100 of the fifth embodiment, the function of changing the focusing diameter of the Gaussian beam, the function of selecting the beam profile, and the function of changing the Rayleigh length of the ring beam. With.

  In the laser processing machine 100 of the first to fifth embodiments described above, the operator operates the operation unit 40 to sort the material of the sheet metal W, the thickness of the sheet metal W, the focusing diameter of the laser beam, the focal position, and the like. Various processing conditions can be set. The material of the sheet metal W is, for example, iron, stainless steel, aluminum, copper, or brass. The plate thickness of the sheet metal W is, for example, any plate thickness within a predetermined range with 0.1 mm to 30 mm being a predetermined range.

  In the laser processing machine 100 according to the first to fourth embodiments, the NC device 50 includes the convex / concave axicon lenses 31, 31B, 31C, 31D, and flat according to the processing conditions of the sheet metal W input by the operation unit 40. The positions of the convex axicon lenses 32, 32C, and 32D are controlled. In the laser processing machine 100 of the fifth embodiment, the NC device 50 controls the positions of the convex lens 36, the concave lens 37, and the plano-concave axicon lens 38 according to the processing conditions of the sheet metal W input by the operation unit 40.

  The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the present invention. The first to fifth embodiments can be combined with each other. For example, the configuration in which the center of the lens in the fourth embodiment is a plane can be combined with the second, third, and fifth embodiments. The fifth embodiment can be combined with a configuration in which the curvature of the convex curved surface in the second and third embodiments is made smaller by providing a predetermined curvature to another surface.

DESCRIPTION OF SYMBOLS 10 Laser oscillator 12 Process fiber 12e Outlet end 20 Laser processing unit 30 Collimator unit 31,31B, 31C, 31D Convex-concave axicon lens 31b4, 32a4 Plane 32, 32C, 32D Plano-convex axicon lens 33 Bend mirror 34 Converging lens 36 Convex lens 37 Concave lens 38 Plano-concave axicon lens 38
39 Biconvex Axicon Lens 40 Operation Unit 50 NC Unit (Control Unit)
DESCRIPTION OF SYMBOLS 100 Laser beam machine 311,321,361,371,381 Movement mechanism 312,322,362,372,382 Driving part 367 Beam diameter variable device W Sheet metal

Claims (8)

A convex and concave axicon lens that has a convex curved surface as a laser light incident surface, a concave axicon surface as a laser light emission surface, and transmits divergent laser light having a Gaussian beam profile;
A plano-convex axicon lens having a convex axicon surface as a laser light incident surface and a flat surface as a laser light emission surface, and transmitting laser light emitted from the convex-concave axicon lens;
A focusing lens that focuses the laser light emitted from the plano-convex axicon lens and irradiates the sheet metal to be processed;
A first moving mechanism for moving the convex / concave axicon lens in the optical axis direction;
A first drive unit configured to drive the convex / concave axicon lens in the optical axis direction by the first movement mechanism;
A second moving mechanism for moving the plano-convex axicon lens in the optical axis direction;
A second drive unit that drives the plano-convex axicon lens to move in the optical axis direction by the second moving mechanism;
A first mode in which the convex / concave axicon lens and the plano-convex axicon lens are brought close to each other so that a beam profile of the laser beam focused by the focusing lens is a Gaussian type, the convex / concave axicon lens and the flat axicon lens The convex-concave axicon lens and the plano-convex axicon lens are switched so as to switch between a second mode in which the beam profile of the laser beam focused by the focusing lens is separated from the convex axicon lens. A control device for controlling the position;
A laser processing machine comprising: Laser light emitted from the exit end of the process fiber is incident on the convex / concave axicon lens, and the distance from the exit end to the convex curved surface is a first distance, and the convex / concave axicon lens and the plano-convex lens The convex curved surface and the concave axicon are arranged such that when the axicon lens is separated from each other, the plano-convex axicon lens emits parallel light by the refraction action of the convex-concave axicon lens and the plano-convex axicon lens. A curvature of each of the surface, the convex axicon surface, and an angle with respect to the optical axis of each of the concave axicon surface and the convex axicon surface,
The control device includes:
The convex-concave axicon lens and the plano-convex axicon lens in a state of being close to each other are set to the first mode by setting a distance from the exit end to the convex curved surface as the first distance,
The convex-concave axicon lens and the plano-convex axicon lens in a state of being separated from each other by setting a distance from the exit end to the convex curved surface as a second distance different from the first distance, The laser beam machine according to claim 1, wherein the laser beam machine is in the second mode. Curvature of the concave axicon surface and the convex axicon surface is 0,
3. The convex curved surface converts divergent light into parallel light, the concave axicon surface converts parallel light into divergent light, and the convex axicon surface converts divergent light into parallel light. Laser processing machine.   The laser processing machine according to claim 2, wherein the concave axicon surface has a predetermined convex curvature, and the curvature of the convex axicon surface is zero.   3. The laser processing machine according to claim 2, wherein the curvature of the concave axicon surface is 0, and the convex axicon surface has a predetermined convex curvature.   The laser processing machine according to any one of claims 1 to 5, wherein a central portion of each of the concave axicon surface and the convex axicon surface is a flat surface. It has a convex lens that receives divergent laser light and converts it into convergent light, and a concave lens that receives the convergent laser light emitted from the convex lens, and has a convergence angle of the convergent light emitted from the convex lens. A beam diameter varying device that varies the beam diameter emitted from the concave lens in response,
A first moving mechanism for moving the convex lens in the optical axis direction;
A first drive unit that drives the convex lens to move in the optical axis direction by the first moving mechanism;
A second moving mechanism for moving the concave lens in the optical axis direction;
A second drive unit that drives the concave lens to move in the optical axis direction by the second moving mechanism;
A laser beam emitted from the beam diameter variable device is incident, a plano-concave axicon lens having a plane as a laser beam incident surface and a concave axicon surface as a laser beam emission surface;
A biconvex axicon that has a convex axicon surface as the laser light incident surface and a convex curved surface as the laser light exit surface, and focuses the laser light emitted from the plano-concave axicon lens and irradiates the sheet metal to be processed. A lens,
A third moving mechanism for moving the plano-concave axicon lens in the optical axis direction;
A third drive unit that drives the plano-concave axicon lens to move in the optical axis direction by the third moving mechanism;
A laser processing machine comprising: The beam diameter varying device corresponds to the position of the convex lens in the optical axis direction, and the concave lens has the same distance as the focal length of the concave lens from the position where the convergent light emitted from the convex lens converges to the convex lens side. When the concave lens is positioned at a position shifted by a distance longer than the focal length of the concave lens, the convergent light is converted into parallel light. Is converted to divergent light,
With the beam diameter varying device emitting parallel light, the plano-concave axicon lens is brought close to the biconvex axicon lens, and the beam profile of the laser beam focused by the biconvex axicon lens is obtained. The biconvex axicon lens is formed by separating the plano-concave axicon lens from the biconvex axicon lens in a state where the first mode is a Gaussian type and the beam diameter varying device emits divergent light. A control device for controlling the positions of the convex lens, the concave lens, and the plano-concave axicon lens so as to switch between the second mode in which the beam profile of the laser beam focused by the ring type is switched;
The laser processing machine according to claim 7, comprising:

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