Laser processing machine and nozzle unit for laser processing machine

Abstract

This invention provides a nozzle unit for a laser processing machine that uses a laser beam to process a workpiece disposed in a light-shielding liquid. The nozzle unit includes an inner nozzle, a gas outlet, and a vortex generator. The laser beam passes through the inner nozzle. The gas outlet blows gas towards the workpiece to remove the light-shielding liquid between the inner nozzle and the workpiece. The vortex generator causes the gas to swirl.

Description

Technical Field

[0001] This invention relates to laser processing machines and nozzle units for laser processing machines. Background Technology

[0002] Laser processing machines perform processes such as cutting on workpieces by irradiating them with a laser beam from a nozzle. Most of the laser beam is absorbed by the workpiece, causing it to melt. However, a portion of the laser beam is reflected within the workpiece and scattered to the surrounding area. Therefore, for example, in the laser processing machine of Patent Document 1, a cover is provided to suppress laser beam scattering. The cover covers the range of motion of the nozzle.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 5940582 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] In the aforementioned laser processing machine, the housing covers the entire range of nozzle movement. This results in a larger machine size. Furthermore, since the laser beam penetrates the workpiece and is reflected from below, it may leak outwards. Installing a housing extending below the workpiece to prevent this leakage complicates the machine's structure.

[0008] Therefore, the inventors of this invention have proposed a laser processing machine in which a workpiece is placed in a light-shielding liquid (hereinafter referred to as "light-shielding liquid"). The light-shielding liquid is, for example, an aqueous solution containing additives such as light-absorbing carbon. The workpiece is placed slightly below the surface of the light-shielding liquid. Thus, the surface of the workpiece is covered by the light-shielding liquid.

[0009] During processing, this laser processing machine blows gas from a nozzle onto the workpiece. This removes the light-shielding liquid from the workpiece surface, and the laser beam is then used to process the workpiece. At this time, the area outside the workpiece surface where gas is blown (hereinafter referred to as the "processing area") is covered by the light-shielding liquid. Therefore, laser beam leakage can be prevented through a simple structure.

[0010] On the other hand, in the aforementioned laser processing machine, when the light-shielding liquid enters the processing area of ​​the workpiece, the processing quality of the workpiece decreases. Therefore, it is desirable to effectively suppress the entry of light-shielding liquid into the processing area of ​​the workpiece. The object of the present invention is to effectively suppress the entry of light-shielding liquid into the processing area of ​​the workpiece in a laser processing machine.

[0011] Technical solutions for solving technical problems

[0012] One embodiment of the nozzle unit of the present invention is a laser processing machine nozzle unit for processing a workpiece disposed in a light-shielding liquid using a laser beam. The nozzle unit includes: an inner nozzle, a gas outlet, and a vortex generator. The laser beam flows through the inner nozzle. The gas outlet blows gas towards the workpiece to remove the light-shielding liquid between the inner nozzle and the workpiece. The vortex generator causes the gas to swirl.

[0013] In the nozzle unit of this method, a swirling flow of gas is generated by a cyclone generator and blown onto the surface of the workpiece. The swirling flow disperses tangentially at the moment of ejection from the nozzle. Therefore, it effectively suppresses the penetration of light-shielding liquid into the workpiece's machining area. Consequently, the workpiece's machining quality is improved.

[0014] Another aspect of the laser processing machine of the present invention includes: a liquid reservoir, a stage, a laser generator, a laser head, a drive unit, and the aforementioned nozzle unit. The liquid reservoir stores a light-shielding liquid. The stage is disposed within the liquid reservoir. The workpiece is placed on the stage. The laser generator generates a laser beam. The laser head is connected to the laser generator and disposed above the stage. The drive unit moves the laser head. The nozzle unit is mounted on the laser head. In this type of laser processing machine, the light-shielding liquid prevents the laser beam from leaking out. Furthermore, the nozzle unit effectively suppresses the light-shielding liquid from entering the processing area of ​​the workpiece. Therefore, the processing quality of the workpiece is improved.

[0015] The effects of the invention

[0016] According to the present invention, in a laser processing machine, the penetration of light-shielding liquid into the processing area of ​​the workpiece can be effectively suppressed. This improves the processing quality of the workpiece. Attached Figure Description

[0017] Figure 1 This is a perspective view of the laser processing machine according to the implementation method.

[0018] Figure 2 This is a schematic diagram showing the structure of a laser processing machine.

[0019] Figure 3 This is a schematic diagram showing the structure of a laser processing machine.

[0020] Figure 4 This is an enlarged view of the laser head and nozzle unit.

[0021] Figure 5 This is a cross-sectional view of the laser head and nozzle unit.

[0022] Figure 6 This is a cross-sectional view of the nozzle unit.

[0023] Figure 7 This is an exploded 3D view of the nozzle unit.

[0024] Figure 8This is a cross-sectional view of a hydrocyclone.

[0025] Figure 9 This is a schematic diagram showing the gas flow in the nozzle unit of the comparative example.

[0026] Figure 10 This is a schematic diagram illustrating the gas flow in the nozzle unit of the embodiment.

[0027] Figure 11 This is a cross-sectional view of the laser head during the workpiece cutting process. Detailed Implementation

[0028] The laser processing machine of the embodiment will now be described with reference to the accompanying drawings. Figure 1 This is a perspective view of the laser processing machine 1 according to the embodiment. Figure 2 This is a schematic diagram showing the structure of laser processing machine 1. Laser processing machine 1 is a device that uses a laser beam to process workpiece W1. Figure 1 As shown, the laser processing machine 1 has: a liquid storage tank 2, a laser head 3, and a drive device 4.

[0029] The storage tank 2 stores a light-shielding liquid L1. The storage tank 2 has a box-like shape with an upward opening. (Example:) Figure 2 As shown, a stage 11 and a sludge tray 12 are arranged inside the liquid storage tank 2. A workpiece W1 is placed on the stage 11. The stage 11 includes, for example, a plurality of interconnected grid-like plate components. The sludge tray 12 is positioned below the stage 11. The sludge tray 12 receives sludge generated during the processing of the workpiece W1 using a laser beam.

[0030] The drive unit 4 moves the laser head 3 above the mounting stage 11. The drive unit 4 moves the laser head 3 in the longitudinal (X), transverse (Y), and vertical (Z) directions. The drive unit 4 includes a first movable stage 13, a second movable stage 14, and a support stage 15. The first movable stage 13 is movably supported relative to the second movable stage 14 in the transverse (Y) direction. The laser head 3 is supported so that it can move in the vertical (Z) direction relative to the first movable stage 13. The second movable stage 14 is supported so that it can move in the longitudinal (X) direction relative to the support stage 15. The first movable stage 13 is... Figure 2 The first motor 16 shown is driven in the horizontal (Y) direction. The laser head 3 is driven by the second motor 17 in the vertical (Z) direction. The second movable stage 14 is driven by the third motor 18 in the vertical (X) direction.

[0031] like Figure 2As shown, the laser processing machine 1 has a laser generator 19. The laser generator 19 generates a laser beam. The laser head 3 is connected to the laser generator 19. The laser generator 19 generates the laser beam, for example, from a fiber laser. The laser beam has, for example, a wavelength of 0.7 μm or more and 10 μm or less. Figure 2 As shown, the laser head 3 is connected to the laser generator 19 via an optical fiber cable 21. The laser head 3 includes a focusing lens 22. The laser head 3 uses the focusing lens 22 to focus the laser beam from the laser generator 19 onto the workpiece W1.

[0032] like Figure 2 As shown, the laser processing machine 1 has a liquid level regulating device 5. The liquid level regulating device 5 changes the liquid level (hereinafter simply referred to as "liquid level") of the light-shielding liquid L1 in the storage tank 2. The liquid level regulating device 5 can adjust the liquid level compared to... Figure 2 The workpiece W1 shown is positioned closer to the bottom than... Figure 3 The liquid level is changed between positions where the workpiece W1 is closer to the top.

[0033] The liquid level regulating device 5 includes a supply pipe 23 and a supply valve 24. The supply pipe 23 is connected to an external tank 25 and a storage tank 2. The external tank 25 is located outside the storage tank 2. The supply valve 24 is connected to the supply pipe 23. By opening the supply valve 24, a light-shielding liquid L1 is supplied from the external tank 25 to the storage tank 2.

[0034] The liquid level regulating device 5 includes: a regulating tank 26, a gas piping 27, a pressure boosting valve 28, and a pressure reducing valve 29. The regulating tank 26 is connected to the storage tank 2. Light-shielding liquid L1 can flow from the regulating tank 26 into the storage tank 2. Additionally, light-shielding liquid L1 can flow from the storage tank 2 into the regulating tank 26. The gas piping 27 connects the regulating tank 26 to a gas supply source (not shown). The pressure boosting valve 28 and the pressure reducing valve 29 are connected to the gas piping 27.

[0035] Gas is supplied to the regulating tank 26 by opening the pressure boosting valve 28. Thus, as... Figure 3 As shown, the light-shielding liquid L1 is squeezed out of the regulating tank 26 and flows into the storage tank 2. This causes the liquid level in the storage tank 2 to rise. Additionally, by opening the pressure-reducing valve 29, gas is discharged from the regulating tank 26 to the outside. Thus, as... Figure 2 As shown, the light-shielding liquid L1 flows from the storage tank into the regulating tank 26. As a result, the liquid level in the storage tank 2 drops.

[0036] The liquid level regulating device 5 includes an overflow pipe 31. The overflow pipe 31 is connected to the storage tank 2 and the external tank 25. When the liquid level in the storage tank 2 is above the specified upper limit, the light-shielding liquid L1 in the storage tank 2 is discharged to the external tank 25 through the overflow pipe 31.

[0037] The liquid level regulating device 5 includes a discharge pipe 32 and a discharge valve 33. The discharge pipe 32 is connected to the storage tank 2 and the external tank 25. The discharge valve 33 is connected to the discharge pipe 32. By opening the discharge valve 33, the light-shielding liquid L1 is discharged from the storage tank 2 to the external tank 25 through the discharge pipe 32.

[0038] The light-shielding liquid L1 suppresses the transmission of the aforementioned laser beam. The transmittance of light in the wavelength region of 0.7 μm to 10 μm of the light-shielding liquid L1 is, for example, 10% / cm or less. Preferably, the transmittance of light in the wavelength region of 0.7 μm to 10 μm of the light-shielding liquid L1 is 5% / cm or less. More preferably, the transmittance of light in the wavelength region of 0.7 μm to 10 μm of the light-shielding liquid L1 is 3% / cm or less.

[0039] In this embodiment, the light-shielding liquid L1 is a liquid in which an additive with light-shielding properties is dispersed in an aqueous solution. The additive includes, for example, carbon black. However, the additive may also be other substances with high light-shielding properties relative to the laser beam. The concentration of carbon black is, for example, 4.0 to 20.0% by weight. Preferably, the concentration of carbon black is 5.0 to 10.0% by weight.

[0040] The laser processing machine 1 includes a liquid level sensor 34 and a transmittance sensor 35. The liquid level sensor 34 detects the liquid level of the light-shielding liquid L1 in the storage tank 2 and outputs a signal indicating the liquid level. The transmittance sensor 35 detects the transmittance of the light-shielding liquid L1 in the storage tank 2 relative to the laser beam and outputs a signal indicating the transmittance.

[0041] The laser processing machine 1 has a controller 36 and an input device 37. The controller 36 includes a processor such as a CPU and a memory. The controller 36 stores programs and data for controlling the laser processing machine 1. The drive device 4 and the laser generator 19 are controlled using signals from the controller 36. The supply valve 24, the pressure boosting valve 28, and the pressure reducing valve 29 are controlled using signals from the controller 36. The controller 36 receives signals from the liquid level sensor 34 and the transmittance sensor 35.

[0042] The input device 37 can be operated by the operator of the laser processing machine 1. The input device 37 may include, for example, a switch. The input device 37 may also include a touch panel. The input device 37 may also include a connection port for an external storage medium. The input device 37 may also be an external computer. The operator can use the input device 37 to input processing conditions. Processing conditions include the thickness, material, processing speed, and design shape of the workpiece W1. The input device 37 outputs signals representing the processing conditions to the controller 36.

[0043] The controller 36 controls the laser processing machine 1 according to the program and processing conditions, thereby cutting the workpiece W1 into the desired shape. The controller 36 controls the liquid level regulating device 5 to change the liquid level of the light-shielding liquid L1 in the liquid storage tank 2. The controller 36 controls the laser generator 19 to irradiate the workpiece W1 with a laser beam from the laser head 3. The controller 36 controls the drive device 4 to move the laser head 3 above the workpiece W1.

[0044] like Figure 3 As shown, in this embodiment, the laser processing machine 1 processes the workpiece W1 when the level of the light-shielding liquid L1 is above the workpiece W1. Figure 4 As shown, a nozzle unit 6 is installed on the laser head 3. The laser head 3 irradiates the workpiece W1 with a laser beam from the nozzle unit 6.

[0045] Additionally, the laser head 3 blows gas from the nozzle unit 6 onto the workpiece W1. This removes the light-shielding liquid L1 from the surface of the workpiece W1, and the workpiece W1 is then processed using the laser beam. At this time, the portion of the workpiece W1 surface outside the processing area is covered by the light-shielding liquid L1. Furthermore, as... Figure 2 As shown, a light shield 38 is installed on the laser head 3. The light shield 38 prevents the laser beam from leaking upwards from the processing area. The processing area is the area on the surface of the workpiece W1 where gas is blown. The processing area includes the laser beam irradiation point on the surface of the workpiece W1. The processing area at least includes the area where the nozzle units 6 face each other.

[0046] The structure of the laser head 3 and the nozzle unit 6 will be described in detail below. The nozzle unit 6 is installed at the front end of the laser head 3. Figure 5 This is a cross-sectional view of the laser head 3 and the nozzle unit 6. (See attached image.) Figure 5 As shown, the laser head 3 includes: a nozzle base 41, a first gas port 42, a second gas port 43, and a third gas port 44.

[0047] A nozzle unit 6 is detachably mounted on a nozzle base 41. The nozzle base 41 includes a mounting hole 45. The mounting hole 45 extends upward from the front end face 46 of the nozzle base 41. A portion of the nozzle unit 6 is disposed within the mounting hole 45. The nozzle base 41 includes a laser passage 47 and a gas passage 48. The laser passage 47 extends in the axial direction.

[0048] It should be noted that, in the following description, "axial direction" refers to the axial direction of nozzle unit 6 and the direction parallel to the axial direction of nozzle unit 6. "Radial" refers to the radial direction of nozzle unit 6 and the direction parallel to the radial direction of nozzle unit 6. The laser beam from laser generator 19 passes through laser path 47. Gas path 48 separates from laser path 47. Gas path 48 is arranged radially outside of laser path 47.

[0049] The first gas port 42, the second gas port 43, and the third gas port 44 are connected to the nozzle base 41. The first gas port 42 and the second gas port 43 communicate with the gas passage 48 within the nozzle base 41. The first gas port 42 is connected to a first gas pipe 51. The second gas port 43 is connected to a second gas pipe 52. The third gas port 44 communicates with the laser passage 47 within the nozzle base 41. Figure 2 The third gas piping 53 is shown.

[0050] like Figure 2 As shown, the laser processing machine 1 has a gas control device 7. The gas control device 7 controls the gas blown from the laser head 3. The gas control device 7 includes a first gas valve 54 and a second gas valve 55. The first gas valve 54 and the second gas valve 55 are controlled by signals from a controller 36. A first gas pipe 51 and a second gas pipe 52 are connected to a gas supply source (not shown) via the first gas valve 54. Protective gas is supplied to the laser head 3 through the first gas pipe 51 and the second gas pipe 52. A third gas pipe 53 is connected to a gas supply source (not shown) via the second gas valve 55. Auxiliary gas is supplied to the laser head 3 through the third gas pipe 53.

[0051] When machining mild steel or low-carbon steel, oxygen is used as an assist gas, for example, because a redox reaction is utilized. When machining stainless steel, since a redox reaction cannot be utilized, nitrogen is used as an assist gas, for example, to prevent the formation of oxides on the cut surface. Regarding the protective gas, since it is used to remove the opacifying liquid L1 from the surface of the workpiece W1, inexpensive compressed air can be used, for example.

[0052] The nozzle unit 6 is detachably mounted relative to the laser head 3. That is, the nozzle unit 6 can be replaced relative to the laser head 3. It should be noted that in the following description of the nozzle unit 6, the direction from the base end of the nozzle unit 6 toward the front end is defined as downward. In addition, the direction from the front end of the nozzle unit 6 toward the base end is defined as upward.

[0053] The front end of nozzle unit 6 refers to the end of nozzle unit 6 along its axial direction that faces the workpiece W1. The base end of nozzle unit 6 is located on the opposite side of the front end of nozzle unit 6 along its axial direction. Figure 6 This is a cross-sectional view of nozzle unit 6. Figure 7 This is an exploded perspective view of nozzle unit 6. (See diagram below.) Figure 6 As shown, the nozzle unit 6 includes: an inner nozzle 61, an outer nozzle 62, and a vortex generator 63.

[0054] The inner nozzle 61 is made of a conductive metal. For example, the inner nozzle 61 is made of copper. However, the inner nozzle 61 can also be made of a metal other than copper. The inner nozzle 61 includes a first opening 64, a second opening 65, and a through hole 66. The first opening 64 is located at the front end 611 of the inner nozzle 61. The second opening 65 is located at the base end 612 of the inner nozzle 61. The through hole 66 communicates with the first opening 64 and the second opening 65. The through hole 66 has a shape that gradually tapers towards the front end 611 of the inner nozzle 61. That is, the inner diameter of the through hole 66 decreases towards the front end 611 of the inner nozzle 61. The through hole 66 is connected to the laser passage 47 within the nozzle base 41.

[0055] A laser beam from laser generator 19 enters the through-hole 66 through the second opening 65. The laser beam passes through the through-hole 66 and irradiates the workpiece W1 through the first opening 64. Additionally, auxiliary gas enters the through-hole 66 through the second opening 65. The auxiliary gas passes through the through-hole 66 and is blown out onto the workpiece W1 through the first opening 64.

[0056] The inner nozzle 61 includes a first nozzle portion 67, a second nozzle portion 68, and a cyclone mounting portion 69. The first nozzle portion 67 extends upward from the front end 611 of the inner nozzle 61. The second nozzle portion 68 extends downward from the base end 612 of the inner nozzle 61. The second nozzle portion 68 is longer than the first nozzle portion 67 in the axial direction. The second nozzle portion 68 is larger than the first nozzle portion 67 in the radial direction.

[0057] A hydrocyclone mounting portion 69 is disposed between a first nozzle portion 67 and a second nozzle portion 68. The hydrocyclone mounting portion 69 is shorter than the first nozzle portion 67 in the axial direction. The first nozzle portion 67 is smaller than the hydrocyclone mounting portion 69 in the radial direction. A first step portion 71 is provided between the first nozzle portion 67 and the hydrocyclone mounting portion 69. The hydrocyclone mounting portion 69 is smaller than the second nozzle portion 68 in the radial direction. A second step portion 72 is provided between the second nozzle portion 68 and the hydrocyclone mounting portion 69.

[0058] A plurality of recesses 73 are provided on the outer peripheral surface of the second nozzle portion 68. It should be noted that only one of the recesses 73 is marked in the accompanying drawings, and the markings for the other recesses 73 are omitted. Each of the recesses 73 has a shape that is recessed from the outer peripheral surface of the second nozzle portion 68. The recesses 73 are arranged circumferentially on the outer peripheral surface of the second nozzle portion 68. The recesses 73 are adjacent to the second stepped portion 72.

[0059] An outer nozzle 62 is disposed on the outer periphery of an inner nozzle 61. The outer nozzle 62 covers a portion of the inner nozzle 61 from the radially outer side. A portion of the outer nozzle 62 protrudes downward from the front end face 46 of the nozzle base 41. A portion of the outer nozzle 62 protrudes to the outside of the laser head 3. The remaining portion of the outer nozzle 62 is disposed within a mounting hole 45 of the nozzle base 41.

[0060] The outer nozzle 62 includes an outer cover 74, a protective cover 75, and an insulating guide 76. The protective cover 75, outer cover 74, and insulating guide 76 are integrated. The protective cover 75, outer cover 74, and insulating guide 76 are joined together, for example, by pressing or bonding. Alternatively, the protective cover 75, outer cover 74, and insulating guide 76 can also be joined together by threaded engagement.

[0061] The outer cover 74 is made of an insulator such as ceramic. However, the outer cover 74 may also be made of other insulators such as resin. The outer cover 74 is disposed on the outer periphery of the front end 611 of the inner nozzle 61. A portion of the outer cover 74 protrudes to the outside of the laser head 3. The remaining portion of the outer cover 74 is disposed within the mounting hole 45 of the nozzle base 41.

[0062] The outer cover 74 includes a bottom surface 77 and a sleeve portion 78. The bottom surface 77 includes a first hole 79. A first nozzle portion 67 communicates with the first hole 79. The bottom surface 77 is disposed on the outer periphery of the first nozzle portion 67. The front end 611 of the inner nozzle 61 protrudes from the bottom surface 77. However, the front end 611 of the inner nozzle 61 may also be flush with the bottom surface 77. The bottom surface 77 is configured facing the workpiece W1.

[0063] The cover sleeve portion 78 extends upward from the cover bottom surface 77. The outer peripheral surface of the cover sleeve portion 78 includes a first groove 81. The first groove 81 extends circumferentially upward on the outer peripheral surface of the cover sleeve portion 78. A [feature / feature] is disposed in the first groove 81. Figure 5 The first O-ring 82 is shown. The first O-ring 82 seals the outer circumferential surface of the external nozzle 62 with the inner circumferential surface of the mounting hole 45. The first O-ring 82 prevents the light-shielding liquid L1 from entering the laser head 3.

[0064] A shield 75 is disposed between the outer cover 74 and the inner nozzle 61. The shield 75 is disposed radially inside the outer cover 74. The shield 75 is made of a conductive metal. For example, the shield 75 is made of brass. However, the shield 75 may also be made of a metal other than brass.

[0065] The protective cover 75 includes a protective cover cylindrical portion 83 and a unit connecting portion 84. The protective cover cylindrical portion 83 has a tubular shape with an open front end. The protective cover cylindrical portion 83 is disposed inside the outer cover 74. The unit connecting portion 84 protrudes upward from the outer cover 74. The unit connecting portion 84 is disposed exposed to the outside of the nozzle unit 6. The unit connecting portion 84 is larger in the radial direction than the protective cover cylindrical portion 83. The nozzle unit 6 is mounted to the nozzle base 41 in the unit connecting portion 84. For example, the unit connecting portion 84 is provided with an external thread, and the inner circumferential surface of the mounting hole 45 is provided with an internal thread. The external thread of the unit connecting portion 84 engages with the internal thread of the mounting hole 45. Thus, the nozzle unit 6 is fixed to the nozzle base 41.

[0066] An insulating guide 76 is disposed between the inner nozzle 61 and the protective cover 75. The insulating guide 76 is disposed radially outward of the inner nozzle 61 and radially inward of the protective cover 75. The protective cover 75 is covered by the outer cover 74 and the insulating guide 76. The insulating guide 76 is made of an electrically insulating material such as resin. Alternatively, the insulating guide 76 may also be made of other insulating materials such as ceramic.

[0067] The insulating guide 76 includes a guide bottom surface 85, a guide cylindrical portion 86, and a guide sealing portion 87. The guide bottom surface 85 is disposed at the front end of the insulating guide 76. The guide bottom surface 85 and the cover bottom surface 77 face each other in the axial direction. The guide bottom surface 85 includes a second hole 88. The second hole 88 is parallel to the first hole 79 in the axial direction. The first nozzle portion 67 passes through the second hole 88. The guide bottom surface 85 is disposed on the outer periphery of the first nozzle portion 67.

[0068] A guide tube portion 86 extends upward from the bottom surface 85 of the guide. A portion of the first nozzle portion 67, the cyclone mount portion 69, and the second nozzle portion 68 are disposed within the guide tube portion 86. The guide tube portion 86 and the bottom surface 85 of the guide are disposed within a protective cover 75. A guide sealing portion 87 protrudes upward from the protective cover 75. The guide sealing portion 87 is disposed exposed to the outside of the nozzle unit 6. The guide sealing portion 87 is larger radially than the guide tube portion 86. The outer peripheral surface of the guide sealing portion 87 includes a second groove 89. The second groove 89 extends circumferentially on the outer peripheral surface of the guide sealing portion 87. A groove 89 is provided in the second groove 89. Figure 5 The second O-ring 91 is shown. The second O-ring 91 is used to seal the area between the outer circumferential surface of the outer nozzle 62 and the inner circumferential surface of the mounting hole 45. The second O-ring 91 prevents leakage of protective gas.

[0069] The nozzle unit 6 includes a gas inlet 92, a gas outlet 93, and a gas passage 94. The gas inlet 92 is located at the base end of the nozzle unit 6. The gas inlet 92 is positioned between the base end 612 of the inner nozzle 61 and the base end 761 of the insulating guide 76. The gas outlet 93 is located at the front end of the nozzle unit 6. The gas outlet 93 is positioned between the front end 611 of the inner nozzle 61 and the bottom surface 77 of the outer cover 74. The gas inlet 92, the gas outlet 93, and the gas passage 94 have an annular shape.

[0070] A gas passage 94 is disposed between the inner nozzle 61 and the outer nozzle 62. More specifically, the gas passage 94 is disposed between the outer peripheral surface of the inner nozzle 61 and the inner peripheral surface of the insulating guide 76. The gas passage 94 communicates with both the gas inlet 92 and the gas outlet 93. Protective gas enters the gas passage 94 from the gas inlet 92. The protective gas passes through the gas passage 94 and exits from the gas outlet 93.

[0071] The cyclone separator 63 causes the protective gas to swirl. The cyclone separator 63 has an annular shape. The cyclone separator 63 is an annular component having a swirling flow generating mechanism for causing the protective gas to swirl. The cyclone separator 63 is disposed within the gas passage 94. The cyclone separator 63 is disposed between the insulating guide 76 and the inner nozzle 61. The cyclone separator 63 is axially disposed between the second step portion 72 of the inner nozzle 61 and the guide bottom surface 85 of the insulating guide 76. The cyclone separator 63 is disposed on the outer periphery of the inner nozzle 61. The cyclone separator 63 is mounted on the cyclone separator mounting portion 69 of the inner nozzle 61.

[0072] For example, the hydrocyclone 63 is press-fitted into the hydrocyclone mounting portion 69. Alternatively, the hydrocyclone 63 can be mounted in the hydrocyclone mounting portion 69 by other mounting methods such as threaded engagement. The first stepped portion 71 of the inner nozzle 61 is disposed within the hydrocyclone 63. The inner diameter of the hydrocyclone 63 is larger than the outer diameter of the first nozzle portion 67. Therefore, a gap is provided between the outer peripheral surface of the first nozzle portion 67 and the inner peripheral surface of the hydrocyclone 63. This gap is contained within the gas passage 94.

[0073] Figure 8 This is a cross-sectional view of hydrocyclone 63. (Example) Figure 8 As shown, the hydrocyclone 63 includes a plurality of holes 95. It should be noted that in the accompanying drawings, only a portion of the plurality of holes 95 is labeled, and the labels for the other holes are omitted. The plurality of holes 95 extend from the outer peripheral surface of the hydrocyclone 63 to the inner peripheral surface. In a cross-sectional view of the hydrocyclone 63 perpendicular to the axial direction, the holes 95 are inclined relative to the radial direction. The holes 95 include a first hole portion 951 and a second hole portion 952. The first hole portion 951 communicates with the outer peripheral surface of the hydrocyclone 63. The second hole portion 952 communicates with the inner peripheral surface of the hydrocyclone 63. The inner diameter of the second hole portion 952 is smaller than the inner diameter of the first hole portion 951.

[0074] The protective gas enters the gas passage 94 from the gas inlet 92. Within the gas passage 94, the protective gas flows from the outside of the hydrocyclone 63 through multiple holes 95 and into the interior of the hydrocyclone 63, thus forming a swirling flow. The protective gas then exits through the gas passage 94 and is ejected from the gas outlet 93 towards the workpiece W1.

[0075] like Figure 2 As shown, the laser processing machine 1 has a nozzle sensor 96. The nozzle sensor 96 detects the height of the inner nozzle 61 relative to the workpiece W1. More specifically, the nozzle sensor 96 detects the capacitance between the inner nozzle 61 and the workpiece W1. The controller 36 calculates the height of the inner nozzle 61 relative to the workpiece W1 using the capacitance. The controller 36 controls the drive device 4 to move the laser head 3 in the height direction based on the height of the inner nozzle 61. The control of the laser processing machine 1 by the controller 36 will be described below.

[0076] First, such as Figure 2 As shown, with the level of the light-shielding liquid L1 below that of the mounting platform 11, the workpiece W1 is placed on the mounting platform 11. When the controller 36 receives a processing start command from the input device 37, it controls the liquid level adjustment device 5 to raise the level of the light-shielding liquid L1. Figure 3 As shown, the controller 36 raises the liquid level to a predetermined position above the workpiece W1. Thus, the workpiece W1 is immersed in the light-shielding liquid L1. For example, the liquid level during processing is located several mm to tens of mm above the workpiece W1. It should be noted that the controller 36 acquires the liquid level based on a signal from the liquid level sensor 34. The controller 36 detects the transmittance of the light-shielding liquid L1 based on a signal from the transmittance sensor 35.

[0077] Then, the controller 36 controls the drive device 4 to move the laser head 3 above the machining start position of the workpiece W1. When the laser head 3 reaches above the machining start position, the controller 36 lowers the laser head 3 towards the workpiece W1 and controls the gas control device 7 to blow out auxiliary gas and protective gas from the nozzle unit 6. Thus, as... Figure 4 As shown, the auxiliary gas and protective gas are blown onto the surface of the workpiece W1 to remove the light-shielding liquid L1 from the processing area of ​​the workpiece W1 surface.

[0078] The controller 36 obtains the height of the inner nozzle 61 above the workpiece W1 based on the signal from the nozzle sensor 96. The controller 36 lowers the inner nozzle 61 to a predetermined height above the workpiece W1. According to the processing conditions, the controller 36 begins processing the workpiece W1 using a laser beam. The controller 36 controls the laser generator 19 to irradiate the workpiece W1 with a laser beam from the laser head 3, cutting the workpiece W1. The controller 36 controls the drive device 4 to move the laser head 3 in the longitudinal (X) and transverse (Y) directions. Thus, the workpiece W1 is cut into a shape conforming to the processing conditions. It should be noted that if the transmittance of the light-shielding liquid L1 exceeds a predetermined threshold, the controller 36 may not begin processing even if it receives a start command, but instead issue an alarm.

[0079] Once workpiece W1 has finished processing, controller 36 stops the laser beam irradiation and gas blowing. Additionally, controller 36 raises the laser head 3, moving it to a predetermined standby position. Controller 36 lowers the level of the light-shielding liquid L1 to a position below workpiece W1. Thus, the cut workpiece W1 can be transported from the mounting table 11.

[0080] In the laser processing machine 1 of this embodiment described above, gas is blown into the processing area of ​​the workpiece W1, and processing is performed using a laser beam. Therefore, the portion outside the processing area is covered by a light-shielding liquid L1. Thus, laser beam leakage can be prevented with a simple structure.

[0081] Furthermore, in nozzle unit 6, a swirling flow of protective gas is generated by swirler 63 and blown onto the surface of workpiece W1. Therefore, the penetration of the light-shielding liquid L1 into the processing area of ​​workpiece W1 can be effectively suppressed. As a result, the processing quality of workpiece W1 is improved.

[0082] For example, Figure 9 This is a cross-sectional view of the nozzle unit 100 and the workpiece W1, which are comparative examples. Figure 9 In the diagram, the dashed arrows indicate the flow of auxiliary gas and protective gas. The comparative example nozzle unit 100 does not have a vortex generator 63; the gas blown from the nozzle unit 6 is an axial flow parallel to the axis. The gas blown from the comparative example nozzle unit 100 collides with the surface of the workpiece W1, thereby changing its direction radially. In this case, the radially directed gas flows close to the surface of the workpiece W1. Therefore, as shown by the dashed arrows, an airflow, such as that drawn into the inner nozzle 101, is generated. Consequently, the light-shielding liquid L1 around the nozzle unit 6 can easily infiltrate the processing area of ​​the workpiece W1. When the light-shielding liquid L1 infiltrates the processing area of ​​the workpiece W1, the processing quality of the workpiece W1 may be reduced. Furthermore, when the inner nozzle 101 is wetted by the light-shielding liquid L1, the electrostatic capacitance between the inner nozzle 101 and the workpiece W1 changes. Therefore, the height of the inner nozzle 101 relative to the workpiece W1 may be misdetected.

[0083] Correspondingly, the nozzle unit 6 of this embodiment blows out a swirling flow of protective gas. Figure 10 This is a cross-sectional view of the nozzle unit 6 and the workpiece W1 in this embodiment. Figure 10 As shown, in the nozzle unit 6 of this embodiment, the swirling flow diverges tangentially at the moment it is blown out from the inner nozzle 61. Therefore, airflow drawn into the inner nozzle 101, as in the nozzle unit 100 of the comparative example, can be suppressed. Therefore, the immersion of the light-shielding liquid L1 into the processing range of the workpiece W1 can be effectively suppressed. As a result, the processing quality of the workpiece W1 is improved. Furthermore, the electrostatic capacitance between the inner nozzle 61 and the workpiece W1 can be detected with good accuracy. Therefore, the height of the inner nozzle 61 relative to the workpiece W1 can be detected with good accuracy.

[0084] The outer nozzle 62 has a triple structure consisting of an outer cover 74, a protective shield 75, and an insulating guide 76. For example... Figure 11 As shown, by using the shield 75, it is possible to suppress the misdetection of changes in capacitance C2 caused by changes in the position of the light-shielding liquid L1 as changes in capacitance C1 between the inner nozzle 61 and the workpiece W1. Furthermore, the shield 75 is covered by an outer cover 74, which acts as an insulator, and an insulating guide 76. This prevents droplets from adhering to the shield 75. Consequently, it is possible to suppress misdetection of the height of the inner nozzle 61.

[0085] Furthermore, the outer cover 74, being made of ceramic, improves resistance to sputtering generated during laser cutting. The insulating guide 76, made of resin, enhances its seal with the nozzle base 41. This, in turn, prevents leakage of protective gas.

[0086] The present invention has been described above with respect to one embodiment, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. The structure of the laser processing machine 1 is not limited to the above embodiment and can also be modified. For example, in the above embodiment, the laser processing machine 1 uses a laser beam to cut the workpiece W1. However, the laser processing machine 1 can also use a laser beam to weld the workpiece W1.

[0087] The laser generator 19 is not limited to a fiber laser, but can also be a solid-state laser such as a YAG laser, or other types of lasers such as a carbon dioxide laser. The structure of the liquid level regulating device 5 is not limited to the above embodiment and can be modified. For example, the liquid level regulating device 5 can also change the liquid level by controlling the supply of the light-shielding liquid L1 to the storage tank 2.

[0088] The structure of nozzle unit 6 is not limited to the above embodiment and can be modified. For example, the cyclone separator 63 can also be provided in a manner that causes the auxiliary gas to swirl. The cyclone separator 63 can also be integrally formed with the inner nozzle 61. The shape of the inner nozzle 61 is not limited to the above embodiment and can be modified. The structure of the outer nozzle 62 is not limited to the above embodiment and can be modified. The shape of the outer cover 74 is not limited to the above embodiment and can be modified. The shape of the protective cover 75 is not limited to the above embodiment and can be modified. The shape of the insulating guide 76 is not limited to the above embodiment and can be modified.

[0089] Industrial applicability

[0090] According to the present invention, in a laser processing machine, the penetration of light-shielding liquid into the processing area of ​​the workpiece can be effectively suppressed. This improves the processing quality of the workpiece.

[0091] Explanation of reference numerals in the attached figures

[0092] 1 Laser processing machine; 2 Liquid storage tank; 3 Laser head; 4 Drive device; 6 Nozzle unit; 11 Platform; 19 Laser generator; 36 Controller; 61 Inner nozzle; 62 Outer nozzle; 63 Swirler; 74 Outer cover; 75 Protective cover; 76 Insulating guide; 84 Unit connection; 93 Gas outlet; 94 Gas passage; 95 Hole; 96 Nozzle sensor.

Claims

1. A nozzle unit for a laser processing machine that processes a workpiece disposed in a light shielding liquid having light shielding properties with a laser beam, characterized by comprising: an inner nozzle through which the laser beam passes; a gas blowout port that blows a gas toward the workpiece in order to remove the light shielding liquid from between the inner nozzle and the workpiece; a swirler that swirls the gas; an outer nozzle disposed on the outer periphery of the inner nozzle; a gas passage that is provided between the inner nozzle and the outer nozzle and communicates with the gas blowout port; the outer nozzle including an insulator outer cover disposed on the outer periphery of the front end of the inner nozzle; and the outer nozzle further including a metal shield disposed between the outer cover and the inner nozzle.

2. The nozzle unit according to claim 1, wherein the swirler is disposed in the gas passage.

3. The nozzle unit according to claim 1 or 2, wherein the swirler has a ring shape and is disposed on the outer periphery of the inner nozzle, and the swirler includes a plurality of holes that are inclined with respect to the radial direction of the swirler in a cross section perpendicular to the axial direction of the swirler.

4. The nozzle unit according to claim 1, wherein the outer nozzle further includes an insulator guide disposed between the inner nozzle and the shield.

5. The nozzle unit according to claim 4, wherein the shield is covered by the outer cover and the insulator guide.

6. The nozzle unit according to claim 4 or 5, wherein the gas passage is provided between the insulator guide and the inner nozzle, and the swirler is disposed between the insulator guide and the inner nozzle.

7. The nozzle unit according to claim 1, wherein the shield includes a unit connection portion that is exposed to the outside of the nozzle unit, and the nozzle unit is attached to the laser processing machine in the unit connection portion. with: a liquid reservoir that stores the light shielding liquid; a placement table that is disposed in the liquid reservoir and places the workpiece; a laser generator that generates the laser beam; a laser head that is connected to the laser generator and is disposed above the placement table; a drive device that moves the laser head; and the nozzle unit according to any one of claims 1 to 7 attached to the laser head. further comprising: a sensor that detects the electrostatic capacity between the inner nozzle and the workpiece; and a controller that calculates the height of the inner nozzle with respect to the workpiece using the electrostatic capacity and controls the drive device to move the laser head in the height direction. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 8. A laser processing machine characterized by comprising: ​ ​ ​ ​ ​ ​ ​ 9. The laser processing machine of claim 8, wherein, ​ ​ ​

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