Laser processing apparatus and laser processing method

Abstract

The invention provides a laser processing apparatus capable of stabilizing a liquid column and prolonging the distance at which laser light is stably guided. A laser processing apparatus (10) is provided with: a liquid supply chamber (16); a nozzle (17) having: a spout (17b) facing the liquid supply chamber (16); and a liquid column formation chamber (17c) which is connected to the nozzle (17b) and through which a liquid column (41) generated from the nozzle (17b) passes. A lead-out tube (21) through which the liquid column (41) passes and which is inserted into the liquid column formation chamber (17c); a liquid column discharge port (22) connected to the delivery pipe (21); a gas introduction path (20) connected to the outside of the delivery pipe (21) inside the liquid column formation chamber (17c); and an optical lens (14) that aligns the focal point of the laser beam to the nozzle (17b) through the liquid supply chamber (16).

Description

Technical Field

[0001] This invention relates to laser processing apparatus and laser processing methods. Background Technology

[0002] A device for generating a liquid jet that internally guides a laser beam is known (e.g., Patent No. 5882927). This device comprises: a fluid nozzle having a nozzle channel; an optical system that focuses the light onto the inlet opening of the nozzle channel; a housing having a space; a gas inlet supplying gas to the space; and a gas outlet nozzle having a gas outlet for discharging gas from the space. The gas outlet is located downstream of the fluid nozzle. Summary of the Invention

[0003] In existing laser processing equipment, there is an issue of liquid column instability. Consequently, the distance required for the processing head to stably guide the laser within the liquid column becomes shorter.

[0004] The purpose of this invention is to provide a laser processing apparatus and a laser processing method that can stabilize a liquid column and extend the distance over which a laser is stably guided.

[0005] The first aspect of this invention is a laser processing apparatus, which has:

[0006] Liquid supply room;

[0007] The nozzle has:

[0008] Nozzle, the nozzle facing the liquid supply chamber; and

[0009] A liquid column forming chamber connected to the nozzle through which a liquid column generated from the nozzle passes;

[0010] An outlet tube, through which the liquid column passes and is inserted into the interior of the liquid column forming chamber;

[0011] A liquid column outlet is connected to the outlet pipe;

[0012] A gas inlet path, the gas inlet path being connected inside the liquid column forming chamber to the outside of the outlet pipe; and

[0013] An optical lens, which directs the focus of the laser toward the nozzle via the liquid supply chamber.

[0014] The second aspect of this invention is a laser processing method, wherein,

[0015] The liquid column formed from the nozzle is discharged from the liquid column outlet.

[0016] Focus the laser beam at the nozzle.

[0017] Gas flows into the nozzle from the lower end of the nozzle, swirling near the nozzle and flowing along the liquid column in a manner that surrounds the liquid column, before exiting from the liquid column outlet.

[0018] Workpieces are processed using a laser propagating within the liquid column.

[0019] Laser processing equipment can have a laser oscillator that oscillates the laser.

[0020] The gas inlet path can be connected to the radial outside of the outlet tube.

[0021] The connecting pipes can extend radially from the nozzle.

[0022] The conical portion can also be directly connected to the cylindrical portion. The conical portion is positioned near the nozzle of the cylindrical portion. The diameter of the conical portion decreases as it moves towards the nozzle. The conical portion can be a straight cone shape.

[0023] A laser oscillator vibrates the laser beam. An optical lens can focus the laser beam at the nozzle.

[0024] The gas can flow from the edge of the liquid column forming chamber of the nozzle into the nozzle, where the gas swirls around and is discharged from the liquid column outlet through the outlet pipe.

[0025] The gas flows in a manner that surrounds the liquid column. The gas velocity is higher than the surface velocity of the liquid column. The gas also flows in a manner that surrounds the liquid column inside the outlet tube or outside the laser head.

[0026] The recess can be configured at the front end of the laser head, having a liquid column outlet for discharging the liquid column. The recess has a bottom surface. The bottom surface can be a plane perpendicular to the central axis of the nozzle. The recess can have a larger diameter as it faces the front end of the laser head. The recess can be frustoconical.

[0027] A liquid column can be formed from the recess of the laser head through the nozzle. The liquid column formed from the nozzle can be discharged from the liquid column outlet located in the recess of the laser head.

[0028] According to the present invention, the liquid column can be stabilized, thereby extending the distance over which the laser is stably guided. Attached Figure Description

[0029] Figure 1 This is a longitudinal cross-sectional view of the laser processing apparatus according to the embodiment.

[0030] Figure 2 yes Figure 1 Sectional view along line II-II.

[0031] Figure 3 yes Figure 1 Sectional view along line III-III.

[0032] Figure 4 This is a longitudinal cross-sectional view when using a laser processing device.

[0033] Figure 5 This is a longitudinal cross-sectional view when using a laser processing device.

[0034] Figure 6 This is a longitudinal cross-sectional view when using a laser processing device.

[0035] Symbol Explanation

[0036] 10 laser processing devices

[0037] 11 laser heads

[0038] 14 optical lenses

[0039] 16 Liquid Supply Room

[0040] 17 nozzles

[0041] 17b nozzle

[0042] 17c liquid column formation chamber

[0043] 20. First gas introduction path (gas introduction path)

[0044] 21 Export tube

[0045] 22 liquid column outlet

[0046] 31 laser oscillator Detailed Implementation

[0047] like Figure 1 As shown, the laser processing apparatus 10 of this embodiment includes a laser oscillator 31, a pump 33, a gas source 35, and a laser head 11. The laser head 11 includes a head body 13, an optical lens 14, a window 15, a nozzle 17, a gasket 18, and a cover 19. Figure 1 yes Figure 2 The image shows a cross-sectional view along line II. The laser head 11 has a central axis 1 and a liquid outlet 22. The laser head 11 is defined as having a front end along the central axis 1 towards the liquid outlet 22. The base end is defined as the direction opposite to the front end.

[0048] Laser oscillator 31 oscillates the laser. Pulsed laser is preferred.

[0049] Pump 33 is, for example, a piston pump. Pump 33 is a liquid pump. Pump 33 pressurizes the liquid to 10 MPa to tens of MPa. The liquid is, for example, water. Gas source 35 is an air compressor or a gas cylinder. Gas source 35 supplies compressed air or helium to the laser head.

[0050] The laser oscillator 31, pump 33, and gas source 35 can also be configured outside the laser processing device 10.

[0051] The head body 13 is cylindrical. From the base end side, the head body 13 sequentially comprises a laser path 13a, a window chamber 13b, a liquid supply chamber 16, a nozzle chamber 13c, a cover chamber 13d, and an end face 13g. The laser path 13a, window chamber 13b, liquid supply chamber 16, nozzle chamber 13c, and cover chamber 13d are arranged along a central axis 1. The laser path 13a is a right circular truncated cone. The window chamber 13b and nozzle chamber 13c are straight cylindrical. The nozzle chamber 13c may have a liner groove (not shown). The liquid supply chamber 16 has a U-shaped cross-section and is a rotating body centered on the central axis 1. The cover chamber 13d is a straight cylindrical body with an internal thread 13f. The internal thread 13f is located at the front end of the cover chamber 13d.

[0052] Nozzle 17 is disposed in nozzle chamber 13c. Nozzle 17 has nozzle head 17a and liquid column forming chamber 17c. Nozzle head 17a is, for example, a gemstone. Hereinafter, gemstone includes artificial gemstone or sintered body of artificial gemstone. Nozzle head 17a has nozzle 17b. Nozzle 17b extends along central axis 1. Liquid column forming chamber 17c is disposed along central axis 1. Liquid column forming chamber 17c may have a cylindrical portion 17f and a conical portion 17d. Cylindrical portion 17f is disposed at the front end of nozzle 17. Cylindrical portion 17f is a straight cylinder. Conical portion 17d is disposed in contact with cylindrical portion 17f. Conical portion 17d is disposed at the base end of cylindrical portion 17f. Conical portion 17d may be a straight cone. The diameter of conical portion 17d decreases as it approaches nozzle 17b.

[0053] Alternatively, the cylindrical portion 17f can be omitted. In this case, the conical portion 17d extends to the front end of the nozzle 17.

[0054] Gasket 18 is disposed in a gasket groove (not shown). Gasket 18 seals between head body 13 and nozzle 17.

[0055] Window 15 is disposed in window chamber 13b. Window 15 is a straight cylinder. Window 15 is, for example, a sapphire plate. The laser passes through window 15. The laser is focused onto nozzle 17b by optical lens 14. Optical lens 14 may have multiple lenses.

[0056] The cover 19 is fastened to the cover chamber 13d. The cover 19 is a straight cylinder. The nozzle 17 is held by the cover 19. The cover 19 has a first surface 19f, a second surface 19g, an outer cylindrical surface 19c, an external thread 19b, a nozzle chamber 19d, a first gas inlet path 20, an outlet pipe 21, a liquid column outlet 22, a second gas inlet path 24, a recess 25, and a gas outlet 26.

[0057] The first surface 19f and the second surface 19g are flat surfaces. The first surface 19f and the second surface 19g are the end faces of the cover 19. The first surface 19f abuts against the bottom surface of the cover chamber 13d. The second surface 19g is substantially the same as the end face 13g. Substantially the same surfaces include cases where the distance between the surfaces is less than 0.5mm.

[0058] The outer cylindrical surface 19c is a cylindrical surface with a diameter smaller than that of the external thread 19b. The outer cylindrical surface 19c is located on the base end side of the side of the cover 19. A gap is provided on the radially outer side of the outer cylindrical surface 19c. The height of the outer cylindrical surface 19c is approximately 50% of the inter-surface distance between the first surface 19f and the second surface 19g. The external thread 19b is located at the front end of the cover 19. The external thread 19b engages with the internal thread 13f.

[0059] A recess 25 is disposed on the second surface 19g. The recess 25 is a right circular frustum shaped around the central axis 1. The recess 25 has a bottom surface 25a and a side surface 25b. The bottom surface 25a is a plane perpendicular to the central axis 1. The side surface 25b is a right circular cone shaped around the central axis 1. The side surface 25b has a diameter that decreases as it faces the first surface 19f.

[0060] The nozzle chamber 19d is disposed with an opening on the first surface 19f. The nozzle chamber 19d is a straight cylinder centered on the central axis 1. The front end portion of the nozzle 17 is housed in the nozzle chamber 19d. The bottom surface of the nozzle chamber 19d abuts against the bottom surface of the nozzle 17. The inner cylindrical surface of the nozzle chamber 19d abuts against the outer cylindrical surface of the nozzle 17.

[0061] like Figure 1 as well as Figure 2 As shown, the first gas introduction path 20 has a first dispersion chamber 20a, a plurality of first connecting pipes 20b, and a collection chamber 20c. The first gas introduction path 20 is disposed on the first surface 19f.

[0062] The first gas introduction path 20 can also be opened on the first surface 19f.

[0063] The first dispersion chamber 20a is a hollow circular plate. The collecting chamber 20c is a hollow circular plate. The outer diameter of the collecting chamber 20c is smaller than the inner diameter of the first dispersion chamber 20a. The collecting chamber 20c is located radially inside the first dispersion chamber 20a. The depth of the collecting chamber 20c from the first surface 19f can be the same as the depth of the first dispersion chamber 20a from the first surface 19f.

[0064] Each first connecting pipe 20b connects the first dispersion chamber 20a and the collection chamber 20c. The first connecting pipe 20b extends radially from the collection chamber 20c. The cross-section of the first connecting pipe 20b is, for example, rectangular. The depth of the first connecting pipe 20b from the first surface 19f can be the same as the depth of the first dispersion chamber 20a from the first surface 19f. The first connecting pipe 20b can be rotationally symmetrical about the central axis 1. Figure 2 As shown, the first connecting pipe 20b in this embodiment is rotated symmetrically 8 times relative to the central axis 1.

[0065] Alternatively, the first connecting pipe 20b can also be configured on the nozzle 17. In this case, the collecting chamber 20c can be integrated with the cylindrical portion 17f.

[0066] The outlet pipe 21 and the liquid column outlet 22 are disposed on the central shaft 1. The outlet pipe 21 is a hollow cylinder. The outlet pipe 21 extends from the upper surface of the collecting chamber 20c toward the nozzle 17. The outlet pipe 21 is disposed inside the liquid column forming chamber 17c. The outlet pipe 21 protrudes towards the base end edge of the collecting chamber 20c. The liquid column outlet 22 is disposed on the bottom surface 25a. The liquid column outlet 22 is a cylindrical hole that communicates with the inner surface of the outlet pipe 21. The inner diameter of the liquid column outlet 22 is the same as the inner diameter of the outlet pipe 21.

[0067] like Figure 1 as well as Figure 3 As shown, the second gas inlet path 24 has a second dispersion chamber 24a, a plurality of second connecting pipes 24b, and a gas supply chamber 24c. The second gas inlet path 24 is positioned at a forward position compared to the first gas inlet path 20. For example, the second dispersion chamber 24a is divided by an outer cylindrical surface 19c and a cover chamber 13d. The second dispersion chamber 24a is a thin-walled cylindrical shape. The second dispersion chamber 24a is positioned radially outside the first dispersion chamber 20a. The gas supply chamber 24c is a hollow circular plate shape. The gas supply chamber 24c is positioned at a forward position compared to the collection chamber 20c. Each of the second connecting pipes 24b connects the second dispersion chamber 24a and the gas supply chamber 24c. The second connecting pipes 24b are positioned at a forward position compared to the first connecting pipes 20b. The second connecting pipes 24b extend, for example, along a straight line passing through the central axis 1. The second connecting pipes 24b can be rotationally symmetrical with respect to the central axis 1. Figure 3 (where n=8). Figure 3 As shown, the second connecting pipe 24b in this embodiment is rotated symmetrically 8 times relative to the central axis 1.

[0068] like Figure 1 As shown, multiple gas outlets 26 extend from the gas supply chamber 24c toward the bottom surface 25a. The gas outlets 26 extend parallel to the central axis 1. Figure 3As shown, the gas outlet 26 is a cylindrical orifice. The gas outlet 26 can be a small-diameter orifice. The diameter of the gas outlet 26 can be less than 1 mm. For example, the diameter of the gas outlet 26 is 0.4 mm to 0.8 mm. The gas outlet 26 is configured to be rotationally symmetrical about the central axis 1. Figure 3 (where n=8). Figure 3 As shown, the gas outlet 26 of this embodiment is rotated symmetrically eight times with respect to the central axis 1. The gas outlet 26 can be disposed at the center of the radial width of the gas supply chamber 24c.

[0069] Alternatively, the gas outlet 26 can extend obliquely in the circumferential direction of a circle centered on the central axis 1. In this case, the gas outlet 26 and the central axis 1 are in a skew position.

[0070] Alternatively, the second gas inlet path 24 and the gas outlet 26 can be omitted.

[0071] like Figure 4 As shown, when pump 33 supplies liquid to laser head 11, a liquid column 41 is formed from nozzle 17b via liquid supply chamber 16. The liquid column 41 is discharged from laser head 11 through liquid column forming chamber 17c, outlet pipe 21, and liquid column outlet 22. Laser oscillator 31 oscillates the laser. The laser's focal point is aligned with nozzle 17b via window 15 and optical lens 14. Thus, the laser propagates inside the liquid column 41.

[0072] When gas source 35 supplies gas to the first gas inlet path 20, the gas is uniformly dispersed within the first dispersion chamber 20a. Gas flows approximately equally into the collection chamber 20c from multiple first connecting pipes 20b. Gas flows out of the collection chamber 20c into the liquid column forming chamber 17c. Within the liquid column forming chamber 17c, the gas forms a swirling flow 42. The gas flows along the periphery of the cylindrical portion 17f towards the nozzle 17b. At the conical portion 17d near the nozzle 17b, the gas changes flow towards the central axis 1. Then, the gas swirls along the liquid column 41 towards the front end from near the nozzle 17b, passes through the center of the liquid column forming chamber 17c, and enters the interior of the outlet pipe 21. The gas is ejected from the liquid column outlet 22.

[0073] Gas flows from near the nozzle 17b of the liquid column forming chamber 17c, surrounding the outer periphery of the liquid column 41. The liquid column 41 is surrounded by a swirling flow 42 of gas, flowing together with the gas flow inside the liquid column forming chamber 17c. In the section from the base of the outlet pipe 21 to the liquid column outlet 22, gas also flows surrounding the liquid column 41. A gas flow 43 ejected from the liquid column outlet 22 flows together with the liquid column 41, surrounding it. The swirling flow 42 and the gas flow 43 flow at a higher velocity than the liquid column 41. The viscosity of the gas is lower than that of the liquid. By causing the gas to flow around the liquid column 41, the velocity of the gas flowing around the surface of the liquid column 41 increases compared to the surface of the liquid column 41. Therefore, the swirling flow 42 and the gas flow 43 reduce the vorticity at the interface between the surface of the liquid column 41 and the gas. Furthermore, the swirling flow 42 and the gas flow 43 promote the rectification of the liquid column 41.

[0074] The outlet pipe 21 extends along the central axis 1 inside the liquid column forming chamber 17c. The collecting chamber 20c is connected to the lower part of the liquid column forming chamber 17c. Thus, gas flows from the periphery of the liquid column forming chamber 17c toward the nozzle 17b, swirles near the nozzle 17b, and flows along the liquid column 41. By generating a swirling flow 42 inside the liquid column forming chamber 17c, a tubular flow of gas is formed around the liquid column 41 discharged from the nozzle 17b. Thus, tilting or turbulence of the liquid column 41 is suppressed inside the liquid column forming chamber 17c. The liquid column forming chamber 17c has a cylindrical portion 17f disposed at the front end and a conical portion 17d disposed at the base end. This promotes the formation of the swirling flow 42.

[0075] The flow of the liquid column 41 becomes turbulent as it moves away from the nozzle 17. At the turbulent position 45 on the outer surface of the liquid column 41, the laser leaks out from the liquid column 41. According to the laser processing apparatus 10, it is possible to effectively cut from the end face 13g to the position 45. The distance from the end face 13g to the position 45 is called the effective cutting length 49. In this embodiment, the first gas introduction path 20 is disposed near the front end face of the nozzle 17. Moreover, the length of the first gas introduction path 20 in the direction of the central axis 1 is short. The second gas introduction path 24 is formed into a thin circular plate. Therefore, the distance 48 from the front end face of the nozzle 17 to the end face 13g is short. As a result, the effective cutting length 49 can be extended.

[0076] The inner diameter of the liquid column outlet 22 is the same as the inner diameter of the outlet pipe 21. Therefore, the gas flow and vorticity of the liquid column 41 are suppressed between the inlet (base end) of the outlet pipe 21 and the liquid column outlet 22. As a result, turbulence in the liquid column 41 can be suppressed, and the effective cutting length 49 can be extended. In addition, the attenuation of the laser within the liquid column 41 can be suppressed. As a result, the processing capability of the laser processing apparatus 10 is improved.

[0077] The energy of the laser propagating on the liquid column tends to decrease as the distance 47 from the nozzle 17 increases. Therefore, it is preferable to make the nozzle 17 and the workpiece 3 as close as possible. In the laser head 11, since the distance 48 is short, the distance 46 between the workpiece 3 and the nozzle 17 can be shortened (see reference). Figure 5 ).

[0078] like Figure 5 As shown, the laser processing apparatus 10 of this embodiment processes the workpiece 3. The workpiece 3 has a surface 3a. When the liquid column 41 collides with the workpiece 3, the liquid column 41 bounces back from the surface 3a and returns to the liquid 51. The bounced liquid 51 becomes droplets 53 and adheres to the front end face of the laser head 11.

[0079] According to existing technology, sometimes droplets 53 are attracted to the liquid column outlet 22. When droplets 53 adhere to the liquid column outlet 22, the liquid column 41 is prone to turbulence. When the liquid column 41 is turbulent, the energy of the laser propagating within the liquid column 41 is easily reduced. In addition, sometimes scum generated during processing adheres to the front end face of the laser head 11 along with droplets 53. When scum and droplets 53 are attracted to the liquid column outlet 22 together, the liquid column outlet 22 is sometimes blocked by scum.

[0080] The laser processing apparatus 10 of this embodiment has a gas ejection port 26. Since the diameter of the gas ejection port 26 is small, the total cross-sectional area of ​​the gas ejection port 26 can be reduced. Therefore, the flow rate of the gas ejected from the gas ejection port 26 can be reduced. Furthermore, even with a reduced gas flow rate, the velocity of the gas ejected from the gas ejection port 26 can be increased. Because the gas flow rate is small, the gas ejected from the gas ejection port 26 has little effect on the liquid column 41. Therefore, turbulence in the liquid column 41 caused by the gas ejected from the gas ejection port 26 can be reduced. The return liquid 51 is divided by the gas ejected from the gas ejection port 26, promoting dispersion. This reduces the adhesion of the return liquid 51 to the front end face of the laser head 11. By increasing the gas velocity, the adhesion of the return liquid 51 can be suppressed.

[0081] The laser processing apparatus 10 of this embodiment has a recess 25. The recess 25 has a bottom surface 25a. A gas outlet 26 is disposed on the bottom surface 25a. By ejecting gas from the gas outlet 26, droplets 53 adhering to the bottom surface 25a move in the outward peripheral direction. Furthermore, most of the droplets 53 are discharged from the side surface 25b through the second surface 19g or the end surface 13g. Since the side surface 25b is inclined outward, the discharge of droplets 53 is promoted. The discharge of droplets 53 is promoted because the second surface 19g and the end surface 13g are substantially the same plane. As a result, the adverse effects of the rebound liquid 51 adhering to the laser head 11 are reduced. In addition, the clogging of the liquid column discharge outlet 22 caused by scum can be suppressed.

[0082] Liquids possess viscosity and surface tension. For example... Figure 6 As shown, when the distance 61 between the laser head 11 and the workpiece 3 is brought close, there is a tendency for liquid to accumulate between the laser head 11 and the workpiece 3. According to the prior art, sometimes the space between the laser head 11 and the surface 3a of the workpiece 3 is filled with liquid. In this case, the processing capability is significantly reduced because the laser cannot be effectively irradiated to the processing point.

[0083] The laser head 11 of this embodiment has a recess 25. A gas ejection port 26 is disposed in the recess 25. Gas is ejected from the gas ejection port 26. The ejected gas promotes the discharge of liquid from between the laser head 11 and the surface 3a in the outward peripheral direction. This facilitates the formation of a gas-filled space between the recess 25 and the workpiece 3. Consequently, the liquid column 41 reaches the surface 3a, promoting the processing of the workpiece 3.

[0084] Alternatively, the gas flow path to the recess 25 (e.g., second gas inlet path 24, gas outlet 26) can be replaced with existing technology (e.g., a second conduit as disclosed in European Patent No. 31054043).

[0085] This invention is not limited to the embodiments described above. Various modifications can be made without departing from the spirit of this invention, and all technical matters included in the technical concept set forth in the claims are subject to this invention. Although the embodiments shown are preferred examples, those skilled in the art can implement various alternatives, modifications, variations, or improvements based on the content disclosed in this specification, and these are included within the technical scope set forth in the appended claims.

Claims

1. A laser processing apparatus (10), comprising: Liquid supply chamber (16); Nozzle (17), said nozzle (17) having: Nozzle (17b), the nozzle (17b) facing the liquid supply chamber (16); and A liquid column forming chamber (17c) is connected to the nozzle (17b) through which a liquid column (41) generated from the nozzle (17b) passes; Outlet tube (21), through which the liquid column (41) passes and is inserted into the interior of the liquid column forming chamber (17c); Liquid column outlet (22), which is connected to the outlet pipe (21); A gas inlet path (20) is provided inside the liquid column forming chamber (17c) and connected to the outside of the outlet pipe (21); and An optical lens (14) is used to focus the laser beam onto the nozzle (17b) through the liquid supply chamber (16).

2. The laser processing apparatus (10) according to claim 1, wherein, It also has a laser oscillator (31) for generating the laser.

3. The laser processing apparatus (10) according to claim 1 or 2, wherein, The liquid column outlet (22) has the same inner diameter as the outlet pipe (21).

4. The laser processing apparatus (10) according to any one of claims 1-3, wherein, The gas introduction path (20) has: An annular dispersion chamber (20a) is disposed radially outside the nozzle (17); An annular collecting chamber (20c) connected to the liquid column forming chamber (17c); and Multiple connecting pipes (20b) connect the dispersion chamber (20a) and the collection chamber (20c).

5. The laser processing apparatus (10) according to claim 4, wherein, The plurality of the connecting pipes (20b) are arranged rotationally symmetrically with respect to the central axis (1) of the nozzle (17b).

6. The laser processing apparatus (10) according to claim 4 or 5, wherein, The connecting pipe (20b) extends in a straight line along the central axis (1) of the nozzle (17b).

7. The laser processing apparatus (10) according to any one of claims 4-6, wherein, The liquid column forming chamber (17c) has a cylindrical portion (17f) centered on the central axis (1) of the nozzle (17b). The collection chamber (20c) is connected to the cylindrical portion (17f).

8. The laser processing apparatus (10) according to claim 7, wherein, The liquid column forming chamber (17c) has a conical portion (17d) disposed on the side closer to the nozzle (17b) than the cylindrical portion (17f) and connected to the cylindrical portion (17f).

9. The laser processing apparatus (10) according to any one of claims 4-6, wherein, The liquid column forming chamber (17c) is a cone shaped with the central axis (1) of the nozzle (17b) as its center, and its cross-section decreases as it moves toward the nozzle (17b), and is connected to the collection chamber (20c).

10. The laser processing apparatus (10) according to any one of claims 1-9, wherein, It also has a cover (19) having the liquid column outlet (22) and a recess (25) at the front end.

11. A laser processing method, wherein, The liquid column (41) formed from the nozzle (17b) of the nozzle (17) is discharged from the liquid column outlet (22). The laser is focused on the nozzle (17b). Gas flows into the nozzle (17b) from the lower end of the nozzle (17), swirling near the nozzle (17b), flowing along the liquid column (41) in a manner that surrounds the liquid column (41), and exiting from the liquid column outlet (22). The workpiece (3) is processed using a laser propagating within the liquid column (41).

12. The laser processing method according to claim 11, wherein, The liquid column (41) is discharged from the liquid column outlet (22) via the outlet pipe (21). The gas is discharged from the liquid column outlet (22) via the outlet pipe (21).

13. The laser processing method according to claim 11 or 12, wherein, The gas is supplied to an annular gas dispersion chamber (20a). The gas is supplied equally from the gas dispersion chamber (20a) to the front end of the liquid column forming chamber (17c) via multiple connecting pipes (20b).

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