Laser processing nozzle

Abstract

To provide a nozzle for laser processing which can supply an assist gas so as to apply a stagnation pressure according to an attitude of an object preferably while inhibiting complication of the structure.SOLUTION: A nozzle for laser processing radiates a laser beam while supplying an assist gas to process an object and includes: a nozzle body. The nozzle body has an outlet part in which an inner diameter of an internal space allowing the assist gas and the laser beam to pass therethrough reduces along an axial direction and which is used to inject the assist gas and the laser beam to the outside. The outlet part has an opening surface which inclines relative to a vertical surface of a center axis of the nozzle body. The opening surface has an area smaller than an internal cross-section which passes through a most upstream position of the opening surface and is orthogonal to the center axis.SELECTED DRAWING: Figure 3

Description

Technical Field

[0005] ,

[0001] The present disclosure relates to a nozzle for laser processing.

Background Art

[0002] A nozzle for laser processing for processing an object by irradiating a laser beam while supplying an assist gas is known. For example, in laser cutting, which is a type of laser processing, the nozzle for laser processing is arranged with respect to the object in a predetermined posture, and the laser beam is irradiated while supplying the assist gas. The nozzle for laser processing is scanned along a predetermined path, and the object is cut while the molten portion by the laser beam is removed by the fluid force of the assist gas.

[0003] For example, Patent Document 1 discloses an example of a nozzle for laser processing used for laser processing in water, and shows a structure in which a configuration for irradiating a laser beam and a configuration for supplying an assist gas are arranged coaxially.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When laser processing is performed using a laser processing nozzle in which laser beam irradiation and assist gas supply are integrated, as described in Patent Document 1 above, the laser irradiation position and the assist gas supply position cannot be controlled independently. Here, when laser processing is performed, if the laser processing nozzle can be installed approximately perpendicular to the surface of the object, sufficient stagnation pressure can be applied to the area to be melted by the laser beam using the assist gas from the laser processing nozzle, and the assist gas can be suitably guided to the back side of the object. However, if the laser processing nozzle cannot be installed perpendicular to the object and is installed at an angle, if the angle of inclination is large, the flow of assist gas from the laser processing nozzle will be deflected by the surface of the object, and sufficient stagnation pressure cannot be applied to the area to be melted by the laser beam. As a result, the assist gas cannot be guided to the back side of the object, and there is a risk of construction defects. Therefore, the above problems arise when the angle of the surface of the object changes relative to the laser processing nozzle during laser processing, or when the posture of the laser processing nozzle is tilted relative to the object in order to access the object.

[0006] At least one embodiment of this disclosure has been made in view of the above circumstances, and aims to provide a laser processing nozzle that can supply assist gas in such a way as to suitably apply stagnation pressure according to the orientation of the object, while suppressing complexity of the configuration. [Means for solving the problem]

[0007] A laser processing nozzle according to at least one embodiment of this disclosure solves the above problem. A laser processing nozzle for processing an object by irradiating it with laser light while supplying an assist gas, The nozzle body comprises an internal space through which the assist gas and the laser beam can pass, the inner diameter of which decreases along the axial direction, and an outlet for ejecting the assist gas and the laser beam to the outside. The outlet portion has an opening surface that is inclined with respect to the vertical plane of the central axis of the nozzle body. The opening surface has an area smaller than the internal cross-section that passes through the uppermost position of the opening surface and is perpendicular to the central axis. [Effects of the Invention]

[0008] According to at least one embodiment of the present disclosure, a laser processing nozzle can be provided that can supply assist gas in such a way as to suitably apply stagnation pressure according to the orientation of the object, while suppressing complexity of the structure. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view showing, from the side, how an object is laser-processed using a laser processing nozzle related to the reference technology. [Figure 2] This figure shows the area near the exit when laser processing is performed with the laser processing nozzle shown in Figure 1 positioned at an angle to the object. [Figure 3] This is a cross-sectional view showing a laser processing nozzle according to one embodiment, along with an object, from the side. [Figure 4] Figure 3 is a schematic diagram of the area near the outlet. [Figure 5] This is a cross-sectional view showing a laser processing nozzle according to another embodiment, along with the object, from the side. [Figure 6] Figure 5 is a schematic diagram of the area near the outlet. [Figure 7] This is a cross-sectional view showing a laser processing nozzle according to another embodiment, along with the object, from the side. [Figure 8] Figure 7 is a schematic diagram of the area near the outlet. [Modes for carrying out the invention]

[0010] Hereinafter, several embodiments of the present invention will be described with reference to the attached drawings. However, the configurations described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0011] Figure 1 is a schematic cross-sectional view showing, from the side, how an object 2 is laser-processed using a laser processing nozzle 1' relating to the reference technology, and Figure 2 is a diagram showing the vicinity of the exit portion 10 when laser processing is performed with the laser processing nozzle 1' of Figure 1 positioned at an angle to the object 2.

[0012] The laser processing nozzle 1' is a device for processing an object 2 by irradiating it with laser light L while supplying assist gas G to the object 2. The laser processing performed by the laser processing nozzle 1' is, for example, laser cutting, but may also be drilling, plasma cutting, or gas cutting. The object 2 is not limited, but in this embodiment it is a structure having a flat plate shape with a predetermined thickness t, and is made of a metal material such as aluminum alloy or stainless steel alloy. The laser light, for example, has a wavelength in the near-infrared region, and the assisting gas is, for example, compressed air, oxygen, argon, or nitrogen.

[0013] The laser beam L emitted from the laser processing nozzle 1' is introduced into the nozzle body 6 via a laser fiber 4 from a laser light source (not shown). The nozzle body 6 has a substantially cylindrical shape with a central axis C and has an internal space 8 through which the laser beam L and assist gas G can pass. The laser fiber 4 is connected to the upstream side of the nozzle body 6 (left side in Figure 1), and the laser beam L introduced into the internal space 8 by the laser fiber 4 is incident on an optical system 11 provided in the internal space 8. The optical system 11 focuses the laser beam L onto the surface of the object 2. The laser beam L irradiated onto the object 2 imparts energy to the surface of the object 2, causing it to melt locally.

[0014] The assist gas G is introduced into the internal space 8 of the nozzle body 6 via a gas line 12 from an assist gas source (not shown). The gas line 12 is connected to the side of the nozzle body 6, and the assist gas G supplied at a predetermined pressure is sprayed from the outlet 10 of the nozzle body 6 toward the object 2, thereby removing the melted portion of the object 2 caused by the laser beam L.

[0015] The nozzle body 6 still includes a first portion 6a to which the laser fiber 4 is connected on the upstream side, and a second portion 6b on the downstream side of the first portion 6a. The first portion 6a has a cylindrical shape in which the internal space 8 has a substantially constant inner diameter with respect to the central axis C, and an optical system 11 is provided in the internal space 8. In the second portion 6b, the internal space 8 has a substantially conical shape in which the inner diameter decreases toward the downstream side along the central axis C, and a gas line 12 is connected to the side. As a result, in the second portion 6b, the laser beam L condensed on the surface of the object 2 by the optical system 11 does not interfere with the inner surface of the internal space 8, and the assist gas G jetted from the outlet portion 10 to the object 2 through the internal space 8 is configured to be accelerated.

[0016] In addition, in FIG. 1, in the laser processing nozzle 1′, the case where the irradiation direction of the laser beam L emitted from the outlet portion 10 and the injection direction of the assist gas G are coaxially configured is illustrated, but they do not have to be coaxial.

[0017] In this way, in the laser processing nozzle 1′, since the irradiation mechanism of the laser beam L and the supply mechanism of the assist gas G are integrally configured, the irradiation position of the laser beam L and the supply position of the assist gas G cannot be independently controlled. Here, when the laser processing nozzle 1′ can be installed substantially perpendicular to the surface of the object 2 as shown in FIG. 1 during the laser processing, a sufficient stagnation pressure can be applied to the molten portion by the laser beam L by the assist gas G from the laser processing nozzle 1′, and the assist gas G can be suitably guided to the back side of the object 2.

[0018] However, as shown in FIG. 2, when the laser processing nozzle 1' cannot be installed perpendicular to the object 2 and has to be installed at an inclination, as the inclination angle θ (the angle of the central axis C with respect to the normal line D to the surface of the object 2) increases, the flow of the assist gas G from the laser processing nozzle 1' is deflected on the surface of the object 2, and sufficient stagnation pressure cannot be applied to the melting portion by the laser beam L. That is, on the obtuse angle side (front side) of the central axis C with respect to the surface of the object 2, most of the flow of the assist gas G is not converted into pressure, and the flow direction changes and flows out forward. As a result, for example, when performing laser cutting, sufficient stagnation pressure cannot be applied to the local melting portion of the object 2 by the laser beam L, and the assist gas G cannot be guided through the melting hole 5 formed in the object 2 to reach the back side of the object 2, which may cause construction defects. Therefore, when the angle of the surface of the object 2 with respect to the laser processing nozzle 1' changes during the laser processing, or when the posture of the laser processing nozzle 1' is inclined with respect to the object 2 to access the object 2, the above problems occur. Such problems can be preferably solved by each of the embodiments described below.

[0019] FIG. 3 is a cross-sectional view showing a laser processing nozzle 1A according to an embodiment together with an object 2 from the side, and FIG. 4 is a schematic view of the vicinity of the outlet portion 10 in FIG. 3. In the following description, components corresponding to the above-described related art will be described using common reference numerals, and redundant descriptions will be omitted unless otherwise specified.

[0020] The laser processing nozzle 1A is a device for processing an object 2 by irradiating it with laser light L while supplying assist gas G, and has a nozzle body 6. The nozzle body 6 has a substantially cylindrical shape in which an internal space 8 through which the assist gas G and laser light L can pass extends along the axial direction of the central axis C. As described above with reference to Figure 1, the nozzle body 6 includes an upstream first part 6a and a downstream second part 6b. The second part 6b has a substantially conical shape such that the inner diameter of the internal space 8 through which the assist gas G and laser light L can pass decreases along the axial direction. An outlet part 10 is provided downstream of the internal space 8 for ejecting the assist gas G and laser light L to the outside toward the object 2.

[0021] The outlet section 10 has an opening surface 14 that is inclined with respect to the vertical plane of the central axis C of the nozzle body 6. In this embodiment, since the internal space 8 has a substantially circular cross-section in the vertical plane of the central axis C, the inclined opening surface 14 has a substantially elliptical shape. As shown in Figure 3, on the cross-section along the central axis C, the opening surface 14 includes the upstream position 14a and the downstream position 14b. In Figure 3, the uppermost position 14a and the lowermost position 14b of the opening surface 14 are shown as an example where they lie on the same cross-section, but they do not necessarily have to lie on the same cross-section.

[0022] The opening surface 14 passes through the uppermost position 14a and has a smaller area than the internal cross-section 15 which is perpendicular to the central axis C. As shown in Figure 4, such a configuration can be identified as satisfying the condition that ∠ABC(θ1) is smaller than ∠ACB(θ2) (∠ABC < ∠ACB) if, on the cross-section passing through the central axis C and the uppermost position 14a, point A is defined as the position corresponding to the uppermost position 14a, point B is defined as the intersection point of the reference line M passing through the uppermost position 14a and perpendicular to the central axis C with the inner surface of the internal space 8, and point C is defined as the position of the opening surface 14 corresponding to the lowermost position 14b.

[0023] In a nozzle body 6 having such a configuration, when the flow velocity of the assist gas G reaches the speed of sound at the outlet 10, the flow direction of the assist gas G is forcibly changed to be approximately perpendicular to the opening surface 14 by the choke effect at the opening surface 14. In this way, the flow direction of the assist gas G, which is guided along the central axis C in the internal space 8 upstream of the outlet 10, is changed to be perpendicular to the opening surface 14 at the outlet 10. This suppresses the evaporative flow of the assist gas G on the surface of the object 2, even when the object 2 is inclined with respect to the central axis C, and generates sufficient stagnation pressure.

[0024] Furthermore, the outlet portion 10 of the nozzle body 6 may have a surface 18 facing the object 2 which is inclined with respect to the central axis C. As shown in Figure 3, when the object 2 is inclined with respect to the central axis C, the gap 19 between the surface of the object 2 and the surface of the object 2 can be narrowed by inclining the facing surface 18 to be substantially parallel to the surface of the object 2, thereby increasing the flow resistance of the assist gas G that is trying to pass through the gap 19. This suppresses the leakage of the assist gas G to the outside from the gap 19 between the outlet portion 10 of the nozzle body 6 and the surface of the object 2, and converts the dynamic pressure of the assist gas G introduced from the internal space 8 of the nozzle body 6 into static pressure, thereby providing a suitable stagnation pressure to the irradiation position of the laser beam L.

[0025] Furthermore, the outlet portion 10 of the nozzle body 6 may have a notch 22 on its outside. By notching the outside of the outlet portion 10 of the nozzle body 6 in this way, interference (catching) of the outlet portion 10 with the object 2 can be effectively reduced when the laser processing nozzle moves (scans) along the object 2, enabling smooth movement (scanning).

[0026] Furthermore, while the notch 22 may be angular as shown in Figure 3, forming it in a curved shape (with rounded corners) can more effectively reduce interference (such as snagging) with the object 2.

[0027] Figure 5 is a cross-sectional view showing a laser processing nozzle 1B according to another embodiment, together with the object 2, from the side, and Figure 6 is a schematic diagram of the vicinity of the outlet portion 10 of Figure 5.

[0028] In the laser processing nozzle 1B, on a cross-section passing through the central axis C and the upstreammost position 14a, the inclination angle of the first region 24 with respect to the central axis C, located downstream of point B which corresponds to the intersection of a reference line M perpendicular to the central axis C and the inner surface of the internal space 8, is greater than the inclination angle of the second region 26 with respect to the central axis C, located upstream of point B (i.e., with point B as the boundary, the inclination angle with respect to the central axis C is configured to increase downstream).

[0029] In the laser processing nozzle 1A shown in Figures 3 and 4, as described above, the flow direction could be changed by the choke effect when the flow velocity of the assist gas G at the outlet 10 reached the speed of sound. Here, the flow velocity of the assist gas G at the outlet 10 depends on the pressure difference between the inside and outside of the internal space 8 relative to the outlet 10, and more specifically, it depends on the supply pressure from the assist gas source (not shown), the diameter and length of the gas line 12, the diameter and length of the internal space 8, etc. Therefore, depending on these configurations, if the flow velocity of the assist gas G at the outlet 10 does not reach the speed of sound, it is difficult to change the flow direction by the choke effect in the laser processing nozzle 1A described above.

[0030] In contrast, in the laser processing nozzle 1B shown in Figures 5 and 6, the inclination angle of the inner surface of the nozzle body 6 with respect to the central axis C increases in the first region 24 near the outlet 10. This causes the assist gas G flowing through the internal space 8 to collide with the inner surface of the nozzle body 6, thereby changing the flow direction of the assist gas G along the internal space 8. As a result, even if the assist gas G does not reach the speed of sound at the outlet 10 and the aforementioned choke effect cannot be expected, the flow direction of the assist gas G can be changed by changing the inclination angle in the first region 24 and the second region 26.

[0031] In Figures 5 and 6, the inner surfaces of the nozzle body 6 in the first region 24 and the second region 26 are connected in a non-curvilinear manner, but they may also be connected in a curvilinear manner. In this case, the inclination angle of the inner surfaces of the nozzle body 6 in the first region 24 and the second region 26 changes smoothly, which reduces pressure loss and allows for a smooth change in the flow direction of the assist gas G, thereby effectively generating stagnation pressure on the target object 2.

[0032] In the laser processing nozzle 1B having such a configuration, the distance between point A and point B corresponding to the upstream position 14a is greater than the distance between point C and point A corresponding to the downstream position 14b (i.e., AB > AC), so that the area of ​​the opening surface 14 at the outlet 10 can be made smaller than the internal cross-section 15 that passes through the upstream position 14a and is perpendicular to the central axis C, similar to the laser processing nozzle 1A described above. As a result, the laser processing nozzle 1B can change the flow direction of the assist gas G by the choke effect, similar to the laser processing nozzle 1A, when the flow velocity of the assist gas G at the outlet 10 reaches the speed of sound. On the other hand, even when the flow velocity of the assist gas G at the outlet 10 does not reach the speed of sound, the flow direction of the assist gas G can be changed by changing the inclination angle of the inner surface of the nozzle body 6 in the first region 24 and the second region 26. As a result, a laser processing nozzle 1B that can be widely used regardless of the flow velocity of the assist gas G at the outlet 10 can be realized.

[0033] Furthermore, in the configuration shown in Figure 6, ∠ACB(θ2) may be 90 degrees. In this case, the flow direction can be suitably changed by causing the assist gas G flowing along the second region 26 on the inner surface of the nozzle body 6 to collide with the first region 24.

[0034] Figure 7 is a schematic cross-sectional view showing a laser processing nozzle 1C according to another embodiment, together with the object 2, viewed from the side, and Figure 8 is a schematic view of the vicinity of the outlet portion 10 of Figure 7.

[0035] In the laser processing nozzle 1C, the first region 24 located downstream of the nozzle body 6 is formed in a concave shape. In other words, the first region 24 is at least partially thinner than the second region 26, and is concave with respect to the dashed line N along the inner surface of the second region 26.

[0036] In the laser processing nozzle 1B shown in Figures 5 and 6, the tip of the first region 24 protrudes relative to the dashed line N. Therefore, depending on the irradiation state of the laser beam L, there is a risk that the laser beam L may interfere with this tip. However, in the laser processing nozzle 1C, the first region 24 is formed in a concave shape relative to the dashed line N. Thus, such interference of the laser beam L is structurally prevented, and the flow direction of the assist gas G can be changed by changing the inclination angle of the inner surface of the nozzle body 6 in the first region 24 and the second region 26.

[0037] If we define point D here as the position with the smallest thickness in the first region 24, then as shown in Figure 8, ∠ACD(θ3) may be 90 degrees. By designing the nozzle body 6 in this way, the laser beam L does not interfere with the inner surface of the nozzle body 6, and the flow direction of the assist gas G, which flows from the upstream second region 26 along the inner surface of the nozzle body 6, is made to collide with the inner surface of the first region 24, thereby suitably changing the flow direction of the assist gas G.

[0038] As described above, according to each of the embodiments described above, it is possible to provide a laser processing nozzle that can supply assist gas G in such a way as to suitably apply stagnation pressure according to the orientation of the object 2, while suppressing the complexity of the configuration.

[0039] Furthermore, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, without departing from the spirit of this disclosure, and the above-described embodiments may also be combined as appropriate.

[0040] The contents described in each of the above embodiments can be understood, for example, as follows:

[0041] (1) A laser processing nozzle according to one embodiment is: A laser processing nozzle (1A, 1B, 1C) for processing an object (2) by irradiating it with laser light (L) while supplying assist gas (G), The nozzle body (6) comprises an internal space (8) through which the assist gas and the laser beam can pass, the inner diameter of which decreases along the axial direction, and an outlet (10) for ejecting the assist gas and the laser beam to the outside. The outlet portion has an opening surface (14) that is inclined with respect to the vertical plane of the central axis (C) of the nozzle body. The opening surface has an area smaller than the internal cross-section (15) that passes through the uppermost position (14a) of the opening surface and is perpendicular to the central axis.

[0042] According to the embodiment of (1) above, in a nozzle body having an internal space in which the inner diameter decreases along the axial direction, the outlet portion from which the assist gas is ejected to the outside has an opening surface inclined with respect to the central axis of the nozzle body. The opening surface has an area smaller than the internal cross-section that passes through the uppermost position of the opening surface and is perpendicular to the central axis. As a result, the assist gas, which is accelerated to the speed of sound toward the outlet portion by the pressure difference between the inside and outside of the internal space, is forcibly changed in flow direction to be approximately perpendicular to the opening surface by the choke effect at the opening surface. In this way, the flow direction of the assist gas guided through the internal space along the central axis is changed at the outlet portion having an opening surface inclined with respect to the central axis, thereby suppressing the stagnation of the assist gas on the surface of the object even when the object is inclined with respect to the central axis, and generating sufficient stagnation pressure.

[0043] (2) In other embodiments, in the embodiment of (1) above, On the cross-section passing through the central axis and the upstreammost position, using point A corresponding to the upstreammost position, point B corresponding to the intersection of a reference line passing through the upstreammost position and perpendicular to the central axis with the inner surface of the internal space, and point C corresponding to the downstreammost position (14b) of the opening surface, ∠ABC(θ1) < ∠ACB(θ2).

[0044] According to the embodiment of (2) above, by designing the nozzle body so that ∠ABC < ∠ACB, the area of ​​the opening surface at the outlet can be made smaller than the internal cross-section.

[0045] (3) In other embodiments, in the embodiment of (1) or (2) above, On a cross-section passing through the central axis and the upstreammost position, the side of the inner surface of the internal space that includes the upstreammost position has a first region downstream of point B, which corresponds to the intersection of a reference line perpendicular to the central axis and the inner surface of the internal space, whose inclination angle with respect to the central axis is greater than the second region upstream of point B, which is located upstream of point B.

[0046] According to the embodiment of (3) above, the inner surface of the nozzle body that defines the internal space, including the upstreammost position, includes a first region downstream of point B and a second region upstream of point B, with the first region having a larger inclination angle with respect to the central axis than the second region. In this way, the inclination angle of the inner surface with respect to the central axis is larger in the first region downstream, which is closer to the outlet. This allows the flow direction of the assist gas to be changed by changing the inclination angle between the first and second regions, even if the assist gas does not reach the supersonic region at the outlet due to specifications of the assist gas supply configuration, for example, if the choke effect described above cannot be expected.

[0047] (4) In other embodiments, in the embodiment of (3) above, The first region and the second region are connected curvilinearly on the cross-section.

[0048] According to the embodiment of (4) above, the first region and the second region are connected in a curved manner, and as the inclination angle with respect to the central axis changes between the first region and the second region, the flow direction of the assist gas can be smoothly changed while reducing pressure loss, thereby effectively generating stagnation pressure on the object.

[0049] (5) In other embodiments, in the embodiment of (3) or (4) above, On the aforementioned cross-section, the distance (AB) between point A, which corresponds to the uppermost position, and point B, is greater than the distance (AC) between point C, which corresponds to the lowermost position on the opening surface, and point A.

[0050] According to the embodiment of (5) above, by designing the distance between point A and point B, and the distance between point A and point C to be greater than the area of ​​the opening surface at the exit, the area of ​​the opening surface at the exit can be made smaller than the internal cross-section.

[0051] (6) In other embodiments, in any one embodiment of (3) to (5) above, On the aforementioned cross-section, using point A corresponding to the upstream position and point C corresponding to the downstream position of the opening surface, ∠ACB is 90 degrees.

[0052] According to the embodiment of (6) above, the flow direction can be suitably changed by causing the assist gas flowing along the second region of the inner surface in the internal space of the nozzle body to collide with the first region of the inner surface.

[0053] (7) In other embodiments, in any one embodiment of (3) to (6) above, On the cross-section, the first region is formed in a concave shape compared to the second region.

[0054] According to the embodiment of (7) above, by forming the second region in a concave shape, the optical path of the laser beam in the internal space of the nozzle body can be avoided, and interference of the laser beam with the inner surface of the nozzle body can be effectively prevented.

[0055] (8) In other embodiments, in the embodiment of (7) above, Using point D, which corresponds to the position with the smallest thickness in the first region, ∠ACD(θ3) is 90 degrees.

[0056] According to the embodiment of (8) above, by designing in this way, the laser beam can be prevented from interfering with the inner surface of the nozzle body, and the flow direction can be suitably changed by causing the assist gas flowing along the second region of the inner surface in the internal space of the nozzle body to collide with the first region of the inner surface.

[0057] (9) In other embodiments, in any one embodiment of (1) to (8) above, The tip of the nozzle body has a surface (18) that is inclined with respect to the central axis.

[0058] According to the embodiment of (9) above, the tip of the nozzle body is inclined with respect to the central axis, thereby reducing the gap between the tip of the nozzle body and the surface of the object when the object is inclined with respect to the central axis, thereby increasing the flow resistance, suppressing the leakage of assist gas from the internal space of the nozzle body to the outside, and allowing suitable stagnation pressure to be applied to the irradiation position of the laser beam.

[0059] (10) In other embodiments, in any one embodiment of (1) to (9) above, The tip of the nozzle body has a notch on the outside.

[0060] According to the embodiment of (10) above, the outer surface of the tip of the nozzle body is notched, which effectively reduces interference between the tip and the object when the laser processing nozzle moves (scans) along the object. [Explanation of symbols]

[0061] 1A, 1B, 1C Laser processing nozzles 2. Object 4 Laser Fibers 5. Molten holes 6. Nozzle body 8 Interior space 10 Exit section 11 Optical system 12 Gas lines 14 Opening surface 14a Most upstream position 14b Most downstream position 15 Internal cross section 18 Opposing surfaces 19 gaps 22 Notch 24 First area 26 Second area C center axis G Assist Gas L Laser light

Claims

1. A laser processing nozzle having a nozzle body having an internal space through which assist gas and laser light can pass, the nozzle body having an outlet for ejecting the assist gas and laser light from the internal space to the outside, the outlet having an opening surface inclined with respect to a plane perpendicular to the central axis of the nozzle body, and for processing an object by supplying the assist gas and irradiating the object with the laser light in a position where the opening surface is substantially parallel to the surface of the object, The inner diameter of the aforementioned internal space decreases along the axial direction. The aforementioned opening surface has an area smaller than the internal cross-section that passes through the uppermost position of the opening surface and is perpendicular to the central axis, and is a laser processing nozzle.

2. A laser processing nozzle according to claim 1, wherein, on a cross section passing through the central axis and the upstreammost position, using point A corresponding to the upstreammost position, point B corresponding to the intersection of a reference line passing through the upstreammost position and perpendicular to the central axis with the inner surface of the internal space, and point C corresponding to the downstreammost position of the opening surface, ∠ABC < ∠ACB.

3. A laser processing nozzle according to claim 1 or 2, wherein, on a cross-section passing through the central axis and the upstreammost position, the inner surface of the internal space on the side including the upstreammost position has a first region downstream of point B corresponding to the intersection of a reference line perpendicular to the central axis and the inner surface of the internal space, and the inclination angle with respect to the central axis is greater than the inclination angle with respect to the central axis of the second region upstream of point B.

4. The laser processing nozzle according to claim 3, wherein the first region and the second region are connected curvilinearly on the cross-section.

5. The laser processing nozzle according to claim 3 or 4, wherein, on the cross-section, the distance between point A, which corresponds to the upstreammost position, and point B is greater than the distance between point C, which corresponds to the downstreammost position of the opening surface, and point A.

6. A laser processing nozzle according to any one of claims 3 to 5, wherein, on the cross-section, using point A corresponding to the upstream position and point C corresponding to the downstream position of the opening surface, ∠ACB is 90 degrees.

7. The laser processing nozzle according to any one of claims 3 to 6, wherein the first region is formed in a concave shape on the cross-section compared to the second region.

8. The laser processing nozzle according to claim 7, wherein ∠ACD is 90 degrees, using point A corresponding to the upstream position, point C corresponding to the downstream position of the opening surface, and point D corresponding to the position with the smallest thickness in the first region.

9. The nozzle for laser processing according to any one of claims 1 to 8, wherein the tip of the nozzle body has a surface inclined with respect to the central axis.

10. The nozzle for laser processing according to any one of claims 1 to 9, wherein the tip of the nozzle body is notched on the outside.

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