Laser processing equipment

Abstract

This suppresses the adhesion of fine particles generated from the processed workpiece to the workpiece itself. [Solution] The laser processing apparatus 10 for processing the workpiece 3 is a laser head 11 having a liquid supply chamber 16 for storing liquid, a liquid nozzle 17 positioned facing the liquid supply chamber 16 and having a nozzle 17b for generating a liquid column 41, an optical lens 14 for focusing the laser onto the nozzle 17b, and a liquid column discharge port 22 through which the liquid column 41 passes, and a mist nozzle 37 positioned at the tip of the laser head 11 for spraying mist 55 toward the workpiece 3.

Description

Technical Field

[0001] The present invention relates to a laser processing apparatus.

Background Art

[0002] A method is known in which a liquid jet is ejected from a machine head, a laser is guided into the liquid jet, a protective shield blank without holes is fixed to the machine head, a through hole is processed in the protective shield blank using the laser guided in the liquid jet, and a workpiece is processed using the laser guided in the liquid jet passing through the through hole (Patent No. 5579733. Hereinafter, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0003] Fine particles generated from the processed workpiece may adhere to the workpiece or the laser head (machine head). An object of the present invention is to provide a laser processing apparatus that suppresses the adhesion of fine particles generated from the processed workpiece to the workpiece or the laser head.

Means for Solving the Problems

[0004] A first aspect of the present invention is a laser processing apparatus for processing a workpiece, a laser head, a liquid supply chamber for storing a liquid, a liquid nozzle disposed facing the liquid supply chamber and having a nozzle for generating a liquid column, an optical lens for focusing a laser on the nozzle, a liquid column discharge port through which the liquid column passes, and a laser head having a mist nozzle disposed at the tip of the laser head and spraying mist toward the workpiece, and a laser processing apparatus having.

[0005] The angles between the mist nozzles and the liquid column may be different. For example, the mist nozzles may be divided into two groups: a first mist nozzle positioned on the first side and a second mist nozzle positioned on the second side when viewed from the liquid column. The angle between the first mist nozzle and the liquid column will be called the first angle. The angle between the second mist nozzle and the liquid column will be called the second angle. In this case, the first angle and the second angle may be different angles. When the mist nozzle's injection axis and the liquid column do not intersect, the point where the injection axis and the liquid column are closest may be located on the back side of the workpiece rather than the front side of the workpiece, as viewed from the machining head.

[0006] The nozzle may have a nozzle facing the liquid supply chamber and a liquid column forming chamber connected to the nozzle through which the liquid column generated from the nozzle passes.

[0007] Laser processing equipment, An outlet pipe through which the liquid column passes and which is inserted into the liquid column forming chamber, A liquid column outlet connected to the aforementioned outlet pipe, Inside the liquid column forming chamber, a gas introduction passage connected to the outside of the outlet pipe, It is acceptable to have it.

[0008] The laser processing apparatus may further include a laser oscillator that generates a laser. The liquid column outlet may have the same inner diameter as the outlet pipe.

[0009] The gas inlet is, An annular dispersion chamber positioned radially outward of the nozzle, An annular collection chamber connected to the liquid column formation chamber, Multiple connecting conduits that connect the distributed rooms and the collective rooms, It is acceptable to have it.

[0010] Multiple connecting pipes may be arranged rotationally symmetrically with respect to the central axis of the nozzle. The connecting pipes may extend along a straight line passing through the central axis of the nozzle.

[0011] The liquid column forming chamber may be conical. The liquid column forming chamber may be centered on the central axis of the nozzle. The diameter of the liquid column forming chamber may increase as it moves away from the nozzle. The liquid column forming chamber may have a straight cylindrical portion centered on the central axis of the nozzle, and the collecting chamber may be connected to the straight cylindrical portion. The liquid column forming chamber may be disposed on the nozzle side of the straight cylindrical portion and may have a conical portion connected to the straight cylindrical portion.

[0012] The laser head may have a recess disposed at the tip and having a liquid column discharge port for discharging a liquid column. The recess may have a bottom surface. The liquid column discharge port may be disposed on the bottom surface. The bottom surface may be a plane perpendicular to the central axis of the nozzle. The liquid column discharge port is disposed in the recess. The recess may have a larger diameter as it approaches the tip of the laser head. The recess may be frustum-shaped.

Advantages of the Invention

[0013] According to the laser processing apparatus of the present invention, it is possible to suppress the adhesion of fine particles generated from the processed workpiece to the workpiece.

Brief Description of the Drawings

[0014] [Figure 1] [[ID=2s1]]Vertical sectional view of the laser processing apparatus of Embodiment 1 [Figure 2] Enlarged view of part II in FIG. 1 [Figure 3] Cross-sectional view taken along line III-III in FIG. 2 [Figure 4] Cross-sectional view taken along line IV-IV in FIG. 2 [Figure 5] Cross-sectional view taken along line V-V in FIG. 1 [Figure 6] Cross-sectional view of the mist nozzle of Embodiment 1 [Figure 7] Vertical sectional view of the laser processing apparatus of Embodiment 1 during use [Figure 8] Vertical sectional view of the laser processing apparatus of Embodiment 1 during use [Figure 9] Vertical sectional view of the laser processing apparatus of Embodiment 2 [Figure 10] Cross-sectional view taken along line X-X in FIG. 9 [Figure 11]Longitudinal cross-sectional view of the laser processing apparatus of Embodiment 3 [Figure 12] Figure 11 shows a cross-sectional view along line XII-XII. [Figure 13] Modified version of Figure 12 [Modes for carrying out the invention]

[0015] <Embodiment 1> As shown in Figure 1, the laser processing apparatus 10 of this embodiment includes a laser oscillator 31, a liquid supply source 33, a gas source 35, a laser head 11, and a mist nozzle 37. The laser head 11 includes a head body 13, an optical lens 14, a window 15, a nozzle (liquid nozzle) 17, a packing 18, and a cap 19. The laser head 11 has a liquid column discharge port 22. With respect to the laser head 11, the side facing the liquid column discharge port 22 along the central axis 1 is considered the tip. Along the central axis 1, the side in the opposite direction to the tip is considered the base.

[0016] The laser oscillator 31 emits a laser. A pulsed laser is preferred. The liquid supply source 33 may have a high-pressure pump and a low-pressure pump. The high-pressure pump is, for example, a piston pump. The liquid supply source 33 is a liquid pump. The liquid supply source 33 pressurizes the liquid to 10 MPa to several tens of MPa. The liquid is, for example, water. The gas source 35 is an air compressor or a gas cylinder. The gas source 35 supplies compressed air or helium gas to the laser head. The laser oscillator 31, liquid supply source 33, and gas source 35 may be located outside the laser processing apparatus 10.

[0017] As shown in Figure 2, the head body 13 is columnar. The head body 13 has, in order from the base end, a laser passage 13a, a window chamber 13b, a liquid supply chamber 16, a nozzle chamber 13c, a cap chamber 13d, and an end face 13g. The laser passage 13a, window chamber 13b, liquid supply chamber 16, nozzle chamber 13c, and cap chamber 13d are arranged along the central axis 1. The laser passage 13a is a frustum of a right circle. The window chamber 13b and nozzle chamber 13c are right cylindrical. The nozzle chamber 13c may have a packing groove (not shown). The liquid supply chamber 16 has a U-shaped cross-section and is a body of rotation about the central axis 1. The cap chamber 13d is a right cylindrical. The cap chamber 13d has an internal thread 13f. The internal thread 13f is located at the tip of the cap chamber 13d.

[0018] The nozzle 17 is located in the nozzle chamber 13c. The nozzle 17 has a nozzle tip 17a and a liquid column forming chamber 17c. The nozzle tip 17a is, for example, a gemstone. Hereinafter, gemstones include artificial gemstones and sintered artificial gemstones. The nozzle tip 17a has a nozzle 17b. The nozzle 17b extends along the central axis 1. The liquid column forming chamber 17c is located along the central axis 1. The liquid column forming chamber 17c may have a cylindrical portion 17f and a conical portion 17d. The cylindrical portion 17f is located at the tip of the nozzle 17. The cylindrical portion 17f is a straight cylinder. The conical portion 17d is connected to the cylindrical portion 17f. The conical portion 17d is located at the base end of the cylindrical portion 17f. The conical portion 17d may be a straight cone. The diameter of the conical portion 17d decreases as it approaches the nozzle 17b. Note that the cylindrical portion 17f may be omitted. In this case, the conical portion 17d extends to the tip of the nozzle 17.

[0019] The packing 18 is positioned in a packing groove (not shown). The packing 18 seals the space between the head body 13 and the nozzle 17.

[0020] Window 15 is located in window chamber 13b. Window 15 is a right-circular column. Window 15 is, for example, a gemstone 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.

[0021] The cap 19 is fastened to the cap chamber 13d. The cap 19 is cylindrical in shape. The nozzle 17 is held by the cap 19. The cap 19 has a first surface 19f, a second surface 19g, an outer cylindrical surface 19c, a male thread 19b, a nozzle chamber 19d, a first gas inlet passage 20, an outlet pipe 21, a liquid column discharge port 22, a second gas inlet passage 24, a recess 25, and a gas outlet 26. The second gas inlet passage 24 and the gas outlet 26 may be omitted.

[0022] The first surface 19f and the second surface 19g are planar. The first surface 19f and the second surface 19g are the end faces of the cap 19. The first surface 19f abuts against the bottom surface of the cap chamber 13d. The second surface 19g is substantially identical to the end face 13g. Substantially identical surfaces include those with a distance between them of 0.5 mm or less.

[0023] The outer cylindrical surface 19c is a cylindrical surface and has a smaller diameter than the male thread 19b. The outer cylindrical surface 19c is located on the base end side of the side surface of the cap 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 distance between the first surface 19f and the second surface 19g. The male thread 19b is located at the tip of the cap 19. The male thread 19b fits into the female thread 13f.

[0024] The recess 25 is located on the second surface 19g. The recess 25 is a frustoconical right circle centered on the central axis 1. The recess 25 has a base surface 25a and a side surface 25b. The base surface 25a is a plane perpendicular to the central axis 1. The side surface 25b is a conical right circle centered on the central axis 1. The side surface 25b has a diameter that decreases towards the first surface 19f.

[0025] The nozzle chamber 19d is positioned with an opening on the first surface 19f. The nozzle chamber 19d is a right cylinder centered on the central axis 1. The tip 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.

[0026] As shown in Figures 2 and 3, the first gas introduction passage 20 includes a first distribution chamber 20a, a plurality of first connecting pipes 20b, and a collection chamber (gas supply chamber) 20c. The first gas introduction passage 20 is located on the first surface 19f. The first gas introduction passage 20 may also be open to the first surface 19f. The first distribution chamber 20a is hollow and disc-shaped. The collection chamber 20c is hollow and disc-shaped. The outer diameter of the collection chamber 20c is smaller than the inner diameter of the first distribution chamber 20a. The collection chamber 20c is located radially inward of the first distribution chamber 20a. The depth of the collection chamber 20c from the first surface 19f may be the same as the depth of the first distribution chamber 20a from the first surface 19f.

[0027] Each first connecting conduit 20b connects the first distribution chamber 20a and the collection chamber 20c. The first connecting conduit 20b extends radially from the collection chamber 20c. The cross-section of the first connecting conduit 20b is, for example, rectangular. The depth of the first connecting conduit 20b from the first surface 19f may be the same as the depth of the first distribution chamber 20a from the first surface 19f. The first connecting conduit 20b may be rotationally symmetric with respect to the central axis 1. As shown in Figure 3, the first connecting conduit 20b in this embodiment is rotationally symmetric eight times with respect to the central axis 1. The first connecting conduit 20b may be located at the nozzle 17. In this case, the collection chamber 20c may be integrated with the cylindrical section 17f.

[0028] The outlet pipe 21 and the liquid column outlet 22 are positioned on the central axis 1. The outlet pipe 21 is a hollow cylinder. The outlet pipe 21 extends from the upper surface of the collection chamber 20c toward the nozzle 17. The outlet pipe 21 is positioned inside the liquid column forming chamber 17c. The outlet pipe 21 protrudes in the proximal direction beyond the proximal edge of the collection chamber 20c. The liquid column outlet 22 is positioned on the bottom surface 25a. The liquid column outlet 22 is a cylindrical hole and 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.

[0029] As shown in Figures 2 and 4, the second gas introduction passage 24 has a second distribution chamber 24a, a plurality of second connecting pipes 24b, and a gas supply chamber 24c. The second gas introduction passage 24 is located further forward than the first gas introduction passage 20. For example, the second distribution chamber 24a is partitioned by an outer cylindrical surface 19c and a cap chamber 13d. The second distribution chamber 24a is thin-walled cylindrical. The second distribution chamber 24a is located radially outward of the first distribution chamber 20a. The gas supply chamber 24c is hollow disc-shaped. The gas supply chamber 24c is located further forward than the collection chamber 20c. Each second connecting pipe 24b connects the second distribution chamber 24a and the gas supply chamber 24c. The second connecting pipes 24b are located further forward than 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 conduit 24b may be rotationally symmetric with respect to the central axis 1. As shown in Figure 4, the second connecting conduit 24b in this embodiment is rotationally symmetric eight times with respect to the central axis 1.

[0030] As shown in Figure 2, multiple gas outlets 26 penetrate from the gas supply chamber 24c toward the bottom surface 25a. The gas outlets 26 extend parallel to the central axis 1. As shown in Figure 4, the gas outlets 26 are cylindrical holes. The gas outlets 26 may be small diameter holes. The diameter of the gas outlets 26 may be 1 mm or less. For example, the diameter of the gas outlets 26 is 0.4 mm to 0.8 mm. The gas outlets 26 are arranged rotationally symmetrically with respect to the central axis 1. As shown in Figure 4, the gas outlets 26 in this embodiment are rotationally symmetrical 8 times with respect to the central axis 1. The gas outlets 26 may be located in the center of the radial width of the gas supply chamber 24c.

[0031] As shown in Figures 1 and 5, the laser processing apparatus 10 may have a plurality (three in this embodiment) of mist nozzles 37. The mist nozzles 37 spray mist 55 so that it spreads in a full cone shape around the injection axis 5. The mist nozzles 37 may also spray mist 55 so that it spreads on a flat plate. Preferably, the mist nozzles 37 are arranged asymmetrically with respect to the central axis 1. In this embodiment, two first mist nozzles 37a and one second mist nozzle 37b are arranged. The first mist nozzle 37a is positioned on the first side of the central axis 1 (lower left in Figure 5). The second mist nozzle 37b is positioned on the second side of the central axis 1 (upper right in Figure 5). The first mist nozzle 37a and the second mist nozzle 37b have the same structure. As shown in Figure 5, the injection axis 5a of the first mist nozzle 37a intersects the central axis 1. The injection axis 5b of the second mist nozzle 37b also intersects the central axis 1. In the circumferential direction, the first mist nozzle 37a and the second mist nozzle 37b are evenly distributed. As shown in Figure 1, the mist nozzles 37a and 37b inject mist 55 toward the machining point of the workpiece 3. The machining point is the intersection of the liquid column 41 and the workpiece 3. However, the angle 38a between the central axis 1 and the injection axis 5a is smaller than the angle 38b between the central axis 1 and the injection axis 5b. The spray angle 37h of the mist nozzle 37 is, for example, 10 to 20 degrees. The spray angle 37h is the angle at which the mist 55 is sprayed. The mist nozzle 37 sprays the mist 55 continuously over time.

[0032] As shown in Figure 6, the mist nozzle 37 has a body 37c, a mixing chamber 37d, a mist nozzle 37e, a gas nozzle 37f, and a liquid inlet 37g. The body 37c is columnar. The mist nozzle 37e is located at the tip of the mist nozzle 37 and extends along the injection axis 5.

[0033] The mixing chamber 37d is located inside the body 37c. The mixing chamber 37d is snowman-shaped. The mixing chamber 37d has a small diameter section 37d1 and a large diameter section 37d2. The small diameter section 37d1 is located at the tip of the mist nozzle 37. The large diameter section 37d2 is located at the base end of the mist nozzle 37. The mist nozzle 37e is located on the injection axis 5 and is connected to the small diameter section 37d1. The mist nozzle 37e injects mist 55 in a full cone or flat plate shape. The gas nozzle 37f is located at the base end of the mist nozzle 37 and extends along the injection axis 5. The gas nozzle 37f is connected to the large diameter section 37d2. The gas nozzle 37f is connected to the gas source 35. The gas nozzle 37f injects gas into the mixing chamber 37d. The gas is, for example, compressed air. The liquid inlet 37g is connected to the large-diameter section 37d2. The liquid inlet 37g is positioned to the side of the body 37c when viewed from the injection axis 5. The liquid inlet 37g is positioned perpendicular to the injection axis 5. The liquid flowing in from the liquid inlet 37g mixes with the gas injected into the mixing chamber 37d, forms droplets, and is sprayed from the mist nozzle 37e.

[0034] As shown in Figure 7, when the liquid supply source 33 supplies liquid to the laser head 11, a liquid column 41 is formed from the nozzle 17b via the liquid supply chamber 16. The liquid column 41 is ejected from the laser head 11 through the liquid column formation chamber 17c, the outlet pipe 21, and the liquid column discharge port 22. The laser oscillator 31 oscillates a laser. The optical lens 14 focuses the laser on the nozzle 17b via the window 15. The laser then propagates inside the liquid column 41.

[0035] When the gas source 35 supplies gas to the first gas inlet passage 20, the gas is evenly distributed within the first distribution chamber 20a. The gas flows almost evenly into the collection chamber 20c from multiple first connecting pipes 20b. The gas flows out of the collection chamber 20c into the liquid column forming chamber 17c. The gas becomes a swirling flow 42 within the liquid column forming chamber 17c. The gas flows along the periphery of the cylindrical section 17f towards the nozzle 17b. At the conical section 17d near the nozzle 17b, the gas changes direction toward the central axis 1. Then, the gas swirls from near the nozzle 17b along the liquid column 41 toward the tip, passes through the center of the liquid column forming chamber 17c, and enters the inside of the outlet pipe 21. The gas is ejected from the liquid column discharge port 22.

[0036] From the vicinity of the nozzle 17b of the liquid column forming chamber 17c, the gas flows so as to envelop the outer circumference of the liquid column 41. The liquid column 41 is enveloped in the swirling gas flow 42 and flows together with the gas flow inside the liquid column forming chamber 17c. In the section from the base end of the outlet pipe 21 to the liquid column discharge port 22, the gas also flows so as to envelop the liquid column 41. The gas flow 43 ejected from the liquid column discharge port 22 flows together with the liquid column 41, enveloping its periphery. The swirling flow 42 and the gas flow 43 flow at a higher speed than the liquid column 41. The gas has a lower viscosity than the liquid. As the gas flows so as to envelop the liquid column 41, the velocity of the gas flowing around the liquid column 41 increases compared to the surface of the liquid column 41. As a result, 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 gas flow 43 promote the straightening of the liquid column 41.

[0037] The outlet pipe 21 extends along the central axis 1 inside the liquid column forming chamber 17c. The collection chamber 20c is connected below the liquid column forming chamber 17c. As a result, the gas flows from the periphery of the liquid column forming chamber 17c toward the nozzle 17b, swirls near the nozzle 17b, and flows along the liquid column 41. The swirling flow 42 is created inside the liquid column forming chamber 17c, forming a tubular flow of gas around the liquid column 41 discharged from the nozzle 17b. This suppresses tilting of the liquid column 41 and turbulence of the flow of the liquid column 41 inside the liquid column forming chamber 17c. The liquid column forming chamber 17c has a cylindrical portion 17f located at the tip and a conical portion 17d located at the base. This promotes the formation of the swirling flow 42.

[0038] The flow of the liquid column 41 begins to become turbulent as it moves away from the nozzle 17. At position 45 where the outer surface of the liquid column 41 becomes turbulent, the laser leaks out of the liquid column 41. According to the laser processing device 10, cutting can be effectively performed between the end face 13g and position 45. The distance from the end face 13g to position 45 is called the effective cutting length 49. In this embodiment, the first gas introduction passage 20 is positioned near the tip face of the nozzle 17. The length of the first gas introduction passage 20 in the direction of the central axis is short. The second gas introduction passage 24 is formed in the shape of a thin disc. Therefore, the distance 48 from the tip face of the nozzle 17 to the end face 13g is short. This makes it possible to increase the effective cutting length 49.

[0039] The inner diameter of the liquid column discharge port 22 is the same as the inner diameter of the outlet pipe 21. Therefore, the vorticity of the gas flow 43 and the liquid column 41 is suppressed between the inlet (base end) of the outlet pipe 21 and the liquid column discharge port 22. This suppresses turbulence in the liquid column 41 and increases the effective cutting length 49. It also suppresses laser attenuation within the liquid column 41. As a result, the processing capacity of the laser processing device 10 is improved.

[0040] The gas flow rate in the mist 55 is slower than that of the gas flow 43. Also, the apparent density of the mist 55 is lower than that of the liquid. Therefore, the effect of the mist 55 on the gas flow 43 is small. As a result, even when the mist nozzle 37 sprays the mist 55, the effective cutting length 49 tends to be maintained.

[0041] The energy of the laser propagating through the liquid column 41 tends to decrease as the distance 47 from the nozzle 17 increases. Therefore, it is preferable to bring the nozzle 17 and the workpiece 3 as close together as possible. With the laser head 11, the distance 48 is short, so the distance between the workpiece 3 and the nozzle 17 can be shortened.

[0042] As shown in Figure 8, 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 rebound liquid 51 bounces back from the surface 3a. The rebound liquid 51 adheres to the tip surface of the laser head 11 as a droplet 53. Furthermore, fine particles 54 generated from the workpiece 3 float between the laser head 11 and the workpiece 3. The fine particles 54 may have adhesive properties.

[0043] According to conventional technology, droplets 53 were sometimes attracted to the liquid column discharge port 22. When droplets 53 adhere to the liquid column discharge port 22, the liquid column 41 is easily disturbed. In this case, the energy of the laser propagating within the liquid column 41 tends to decrease. In addition, dross generated during processing, along with the droplets 53, sometimes adhered to the tip surface of the laser head 11. When the dross, along with the droplets 53, was attracted to the liquid column discharge port 22, the liquid column discharge port 22 could become clogged with the dross.

[0044] Furthermore, fine particles 54 sometimes adhere to the laser head 11 or the workpiece 3. When fine particles 54 adhere to and accumulate at the liquid column discharge port 22, the liquid column 41 is easily disturbed. Also, the liquid column 41 is more likely to tilt. Furthermore, due to the fluid resistance of the gas flow 43 flowing around the liquid column 41, fine particles 54 floating between the laser head 11 and the workpiece 3 tend to flow towards the workpiece 3. In some cases, fine particles 54 adhering to the surface 3a or floating near the surface 3a may become fixed to the surface 3a due to the gas flow.

[0045] The laser processing apparatus 10 of this embodiment has a mist nozzle 37. The mist 55 sprayed by the mist nozzle 37 lowers the temperature of the fine particles 54. In addition, the mist 55 cleans the surface 3a. Since angle 38a is larger than angle 38b, the mist flows on the workpiece 3 toward the second side (upper right in Figure 5). Thus, because the installation angles of the mist nozzle 37a and the mist nozzle 37b are different, the flow of mist on the surface 3a becomes unbalanced. This suppresses the accumulation of droplets sprayed on the surface 3a near the processing point. As a result, the adhesion of fine particles 54 to the surface 3a is suppressed. Furthermore, the uneven flow of mist on surface 3a promotes the discharge of liquid from near the processing point. This suppresses laser scattering caused by liquid accumulation near the processing point, thereby preventing a decrease in processing capability. Furthermore, the spraying of mist 55 from the mist nozzle 37 helps to suppress disturbance of the liquid column 41.

[0046] The laser processing apparatus 10 of this embodiment has a gas nozzle 26. Because the diameter of the gas nozzle 26 is small, the total cross-sectional area of ​​the gas nozzle 26 can be reduced. Therefore, the flow rate of the gas ejected from the gas nozzle 26 can be reduced. Furthermore, even if the gas flow rate is reduced, the flow velocity of the gas ejected from the gas nozzle 26 can be increased. Because the gas flow rate is small, the effect of the gas ejected from the gas nozzle 26 on the liquid column 41 is small. Accordingly, turbulence of the liquid column 41 caused by the gas ejected from the gas nozzle 26 can be reduced. The gas ejected from the gas nozzle 26 divides the reflected liquid 51, promoting scattering. This reduces the adhesion of reflected liquid 51 to the tip surface of the laser head 11. By increasing the gas flow velocity, the adhesion of reflected liquid 51 can be suppressed.

[0047] The laser processing apparatus 10 of this embodiment has a recess 25. The recess 25 has a bottom surface 25a. The gas nozzle 26 is located on the bottom surface 25a. By injecting gas from the gas nozzle 26, droplets 53 adhering to the bottom surface 25a move outward. Most of the droplets 53 are then discharged from the side surface 25b, passing through the second surface 19g and the end surface 13g. The side surface 25b is inclined outward, which promotes the discharge of droplets 53. The fact that the second surface 19g and the end surface 13g are substantially the same plane also promotes the discharge of droplets 53. This reduces the adverse effect of splashed liquid 51 adhering to the laser head 11. It also suppresses clogging of the liquid column discharge port 22 due to dross.

[0048] Furthermore, even if the gas nozzle 26 is not present, the side surface 25b is inclined outward, so the droplets 53 are easily discharged from near the liquid column outlet 22.

[0049] Furthermore, the gas flow path to the recess 25 (for example, the second gas inlet passage 24 or the gas outlet 26) may be replaced with a prior art (for example, a second conduit as described in European Patent No. 31054043). Furthermore, the laser head assembly 12 may be replaced with a prior art design (for example, Japanese Patent No. 5147445, Japanese Patent No. 6318428, and Japanese Patent No. 5877432).

[0050] <Embodiment 2> As shown in Figure 9, the laser processing apparatus 100 of this embodiment has a laser head 111 instead of the laser head 11 of the first embodiment. The other structures of the laser processing apparatus 100 are substantially the same as those of the laser processing apparatus 10 of Embodiment 1. The laser head 111 includes a head body 113, a window 15, a nozzle 17, a nozzle cover 127, and a cap 119.

[0051] The head body 113 has a cap chamber 113d instead of a cap chamber 13d. The rest of the structure of the head body 113 is substantially the same as that of the head body 13 of Embodiment 1. The cap chamber 113d is stepped cylindrical. The cap chamber 113d has an internal thread 13f.

[0052] The nozzle cover 127 has a flange 127a, a nozzle chamber 127e, a nozzle-side projection 127b, a liquid column passage 127c, and a gas groove 127d. The flange 127a is disc-shaped and abuts against the base end surface of the cap chamber 113d. The nozzle chamber 127e is a straight cylinder and is located at the base end of the flange 127a. The nozzle chamber 127e abuts against the nozzle 17 on two surfaces: the cylindrical side and the bottom surface. The nozzle-side projection 127b is located on the tip side of the flange 127a. The nozzle-side projection 127b is a frustoconical shape centered on the central axis 1. The diameter of the nozzle-side projection 127b decreases towards the tip. The liquid column passage 127c is a straight cylinder centered on the central axis 1 and penetrates the nozzle cover 127. As shown in Figure 10, multiple (four in this embodiment) gas grooves 127d are arranged rotationally symmetrically with respect to the central axis 1. The gas grooves 127d are located on the tip surface of the flange 127a. The gas grooves 127d have a rectangular cross-section and extend radially. The radially inner end of the gas groove 127d, as viewed from the central axis 1, may be semicircular.

[0053] The cap 119 has an inlet chamber 119a, a swirling chamber (gas supply chamber) 119b, a liquid column discharge port 22, a cap projection 119c, a male screw 119d, and a recess 125. The cap 119 is cylindrical. The diameter of the inlet chamber 119a decreases towards the tip. The inlet chamber 119a is a frustoconical shape with respect to the central axis 1. There is a gap between the inlet chamber 119a and the nozzle-side projection 127b. The swirling chamber 119b is cylindrical with respect to the central axis 1. The swirling chamber 119b is located on the tip side of the inlet chamber 119a and is connected to the inlet chamber 119a. The cap projection 119c is located on the tip surface of the swirling chamber 119b. The cap projection 119c is cylindrical or frustoconical with respect to the central axis 1. The diameter of the cap projection 119c decreases towards the base end. The liquid column outlet 22 penetrates the cap 119. The liquid column outlet 22 is located on the cap projection 119c. The recess 125 is located at the tip of the cap 119. The recess 125 is substantially identical to the recess 25 of the first embodiment. The cylindrical cap projection 119c and the liquid column outlet 22 may be replaced with an inlet pipe. The cap projection 119c may also be omitted.

[0054] The gas introduction passage 124 has a distribution chamber 124a and a connecting passage 124b. The distribution chamber 124a is defined between the flange 127a and the cap chamber 113d. The distribution chamber 124a is hollow and cylindrical. The connecting passage 124b is separated from the cap chamber 113d by the gas groove 127d. The connecting passage 124b has a rectangular cross-section and extends radially. The connecting passage 124b connects the introduction chamber 119a and the distribution chamber 124a. The gas passes through the gas inlet passage 124 and the inlet chamber 119a, swirls in the swirling chamber 119b, and is ejected from the liquid column discharge port 22 as a gas flow 43. The gas flow 43 flows along the central axis 1, enveloping the liquid column 41.

[0055] <Embodiment 3> As shown in Figure 11, the laser processing apparatus 200 of this embodiment has a processing head 211 and a mist nozzle 39. The processing head 211 is substantially the same as the laser processing apparatus 10 of Embodiment 1, except that it has a cap 219 instead of a cap 19.

[0056] The cap 219 does not have the second gas introduction passage 24 and the gas outlet 26 of the first embodiment. The other configurations of the cap 219 are substantially the same as those of the cap 19 of the first embodiment.

[0057] The mist nozzle 39 sprays mist 55 in a solid cone shape centered on the injection axis 5c. As viewed from the machining head 211, the injection axis 5c intersects the central axis 1 on the back side of the workpiece 3. The angle 40c between the injection axis 5c and the central axis 1 is, for example, 65 to 75 degrees. The spray angle 39h of the mist nozzle 39 is, for example, 15 to 25 degrees. The orientation of the mist nozzle 39 is adjusted so that the mist 55 does not collide with the machining head 211. The water flow rate of the mist 55 is 0.040 L / min to 0.150 L / min. The air flow rate of the mist 55 is 2 to 8 L / min per nozzle at atmospheric pressure and 25 degrees Celsius. The other configurations of the mist nozzle 39 are substantially the same as those of the mist nozzle 37 of Embodiment 1.

[0058] According to this embodiment, a suitable liquid film is formed on the workpiece 3, suppressing sludge adhesion to the workpiece 3. Furthermore, since the impact on the liquid column 41 is small, the processing capacity is less likely to decrease.

[0059] The laser processing apparatus 200 has one or more mist nozzles 39. Preferably, the laser processing apparatus 200 has multiple (three in this embodiment) mist nozzles 39. The multiple mist nozzles 39 are arranged rotationally symmetrically with respect to the central axis 1. As shown in Figure 12, the area 6 in which the mist 55 collides with the workpiece 3 is away from the central axis 1.

[0060] If the airflow rate is low, the machining capacity decreases. This is thought to be because the droplets of mist 55 become larger, and the water adhering to the machining head 211 disrupts the jet. If the airflow rate is high, the impact on machining capacity is small. In this case, the water film on the workpiece 3 is blown away, so sludge adhesion to the workpiece 3 is not suppressed very well.

[0061] When the water flow rate is high, the liquid film formed on the workpiece 3 tends to become thicker. In this case, the laser light is more likely to scatter, and the processing capacity tends to decrease. When the water flow rate is low, the formation of a liquid film on the workpiece 3 is suppressed. As a result, the effect of suppressing sludge adhesion to the workpiece 3 tends to decrease.

[0062] When the angle 38c is large, water is more likely to adhere to the machining head 211. This tends to reduce machining capacity. When the angle 38c is small, water is less likely to adhere to the machining head 211. In this case, the impact on machining capacity is small. However, the amount of water adhering to the workpiece 3 decreases, and the formation of a water film on the workpiece 3 is suppressed. As a result, the effect of suppressing sludge adhesion to the workpiece 3 tends to decrease.

[0063] When the number of mist nozzles 39 is small, the water film thickness on the workpiece 3 may vary. This can lead to variations in the amount of sludge adhering to the workpiece 3. Using multiple mist nozzles 39 makes it easier to achieve a uniform water film thickness on the workpiece 3. This reduces variations in the amount of sludge adhering to the workpiece 3.

[0064] <Variation> As shown in Figure 13, the injection axis 5d may be changed to be at a twisted position with respect to the central axis 1. In this case, the injection axis 5d does not intersect with the central axis 1. Even in this case, the mist nozzle 39 is arranged rotationally symmetrically with respect to the central axis 1. The injection axis 5d is also arranged rotationally symmetrically with respect to the central axis 1.

[0065] According to this modified version, the mist 55 does not collide with the liquid column 41. This suppresses disturbance of the liquid column 41, and thus suppresses a decrease in processing capacity. In addition, a water film can be formed on the upper surface of the workpiece 3. This suppresses the adhesion of sludge to the workpiece 3.

[0066] The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. All technical matters included in the technical concept described in the claims are covered by the present invention. The embodiments described above are preferred examples, but those skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed herein, and these are included in the technical scope described in the appended claims. [Explanation of Symbols]

[0067] 10, 100, 200 laser processing equipment 11, 111, 211 Laser Heads 14 Optical Lenses 16 Liquid supply chamber 17 nozzles 17b spout 17c Liquid column formation chamber 20. First gas introduction channel (gas introduction channel) 21 Outlet pipe 22 Liquid column outlet 37, 39 Mist nozzle

Claims

1. A laser processing device for processing a workpiece, It is a laser head, A liquid supply chamber for storing liquid, A liquid nozzle having a nozzle that generates a liquid column is positioned facing the liquid supply chamber, An optical lens for focusing the laser onto the nozzle, A liquid column discharge port through which the liquid column passes, A laser head having, A mist nozzle is positioned at the tip of the laser head and sprays mist toward the workpiece, A laser processing device having the following features.

2. The mist nozzle is, Mist nozzle and A mixing chamber connected to the mist nozzle, A gas nozzle is provided in the mixing chamber and injects gas along the injection axis passing through the mist nozzle, A liquid inlet is provided in the mixing chamber for injecting the liquid into the mixing chamber from the side of the injection axis, A laser processing apparatus according to claim 1, having the following features.

3. The mist nozzle sprays the mist toward the vicinity of the machining point where the liquid column collides with the workpiece. The laser processing apparatus according to claim 1 or 2.

4. The injection axis of the mist nozzle intersects with the liquid column. A laser processing apparatus according to any one of claims 1 to 3.

5. The system has a plurality of mist nozzles arranged asymmetrically with respect to the liquid column, A laser processing apparatus according to any one of claims 1 to 4.

6. The mist nozzle sprays continuously over time. A laser processing apparatus according to any one of claims 1 to 5.

7. The mist nozzle sprays the mist in a flat or conical shape. A laser processing apparatus according to any one of claims 1 to 6.

8. The laser head is positioned at the tip of the liquid nozzle and has a gas supply chamber connected to the liquid column discharge port. The aforementioned liquid column outlet ejects the gas supplied to the gas supply chamber. A laser processing apparatus according to any one of claims 1 to 7.

9. The mist nozzle is positioned radially outward from the laser head as viewed from the liquid column, and sprays the mist toward a position away from the machining point where the liquid column collides with the workpiece. The laser processing apparatus according to claim 1 or 2.

10. The system has a plurality of mist nozzles arranged symmetrically with respect to the liquid column, The laser processing apparatus according to claim 9.

11. The injection axis of the mist nozzle intersects the liquid column at a point on the back side of the workpiece as viewed from the laser head. The laser processing apparatus according to claim 9 or 10.

12. The spray axis of the mist nozzle does not intersect with the liquid column. The laser processing apparatus according to claim 9 or 10.

13. The mist nozzle sprays the mist in a flat or conical shape. A laser processing apparatus according to any one of claims 9 to 11.

14. Each of the mist nozzles has a gas flow rate of 2 to 8 L / min. A laser processing apparatus according to any one of claims 1 to 13.

15. Each of the mist nozzles has a liquid flow rate of 0.040 L / min to 0.150 L / min. A laser processing apparatus according to any one of claims 1 to 14.

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