JP2014054638A - Nozzle for laser processing head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing head nozzle capable of making uniform flows of assist gas in an annular assist gas passage between an inner nozzle and an outer nozzle, and suppressing sputtering and entry of return light into the inner nozzle.SOLUTION: A laser processing head nozzle provided with a plurality of communication holes 41 communicating an annular assist gas passage 57 with an interior of an inner nozzle 23 in the inner nozzle 23 comprises an annular pressure adjustment unit 53 in a base portion of the assist gas passage 57 for making uniform annular gas flows of assist gas ejected from the respective communication holes 41 and directed to a nozzle port 49 provided on a tip end of an external nozzle 25. Each communication hole 41 is provided to be directed to the pressure adjustment unit 53, the pressure adjustment unit 53 includes an annular stepped portion 45 forming a throttle portion 55 between the annular stepped portion 45 and an outer circumferential surface of the inner nozzle 23, and each communication hole 41 is provided upward of the stepped portion 45.

Description

  The present invention relates to a double-structure nozzle used in a laser processing head, and more specifically, a sputter that suppresses the incidence of return light from the laser processing position and scatters from the laser processing position to the condenser lens side. It is related with the nozzle for laser processing heads which can suppress etc.

  When performing laser processing of a workpiece, a double-structure nozzle is used to inject and supply assist gas to a laser processing position (see, for example, Patent Document 1).

JP 2010-234373 A

  Patent Document 1 describes a double-structure nozzle having an outer nozzle outside the inner nozzle. The dual-structure nozzle has a configuration in which assist gas is supplied from separate assist gas supply sources into the inner nozzle and the annular assist gas passage formed between the inner nozzle and the outer nozzle. is there. Further, there is a configuration in which the inner nozzle is provided with a communication hole communicating with the annular assist gas passage (see FIG. 6 of Patent Document 1).

  The latter configuration described in Patent Document 1 is a configuration as shown in FIG. That is, the conventional double-structure nozzle 1 includes an outer nozzle 5 outside the tapered inner nozzle 3, and is tapered between the outer peripheral surface of the inner nozzle 3 and the inner peripheral surface of the outer nozzle 5. An annular assist gas passage 7 is provided. The assist gas supplied from the assist gas supply source 9 into the inner nozzle 3 is jetted into the assist gas passage 7 from a plurality of communication holes 11 provided in the inner nozzle 3.

  In the above-described configuration, the work W is irradiated with the laser beam LB oscillated from the laser oscillator 13 and the assist gas is supplied from the assist gas supply source 9 into the inner nozzle 3, so that a part of the assist gas is in the inner nozzle 3. Are ejected from the nozzle port 15. A part of the assist gas is ejected from the communication hole 11 to the assist gas passage 7 and is ejected from the nozzle port 17 of the outer nozzle 5 to the laser processing position 19 of the workpiece W.

  At the time of piercing as laser processing, if a part of the reflected light from the laser processing position 19 enters the inside from the nozzle opening 15 of the inner nozzle 3 as return light, the optical system such as an optical fiber may be damaged. . Therefore, it is desired to suppress the return light from entering from the nozzle port 15.

  Further, when spatter or the like scattered from the laser processing position 19 enters the inside from the nozzle port 15, it may adhere to, for example, a condenser lens and be damaged. In addition, spatter and the like scattered from the laser processing position 19 may adhere to the outer peripheral surface of the inner nozzle 3 and the communication hole 11.

  By the way, since the assist gas is ejected from the communication hole 11 into the assist gas passage 7, the assist gas flows toward the nozzle port 17 in the assist gas passage 7. Since the position of the communication hole 11 is provided at the proximal end portion of the assist gas passage 7, the assist gas ejected from the communication hole 11 into the assist gas passage 7 abuts against the inner peripheral surface of the outer nozzle 5. When flowing in the direction of the nozzle port 17 along the inner peripheral surface of the outer nozzle 5, the flow gradually spreads along the inner peripheral surface and then tends to gather at the nozzle port 17.

  Therefore, the flow of the assist gas at the nozzle port 17 is likely to be uneven, and the uniformity of blowout of dross or the like may be lacking depending on the laser cutting process progress direction of the workpiece. Moreover, when the assist gas is ejected from the communication hole 11, sputtering or the like tends to be easily caught on and attached to the outer peripheral surface of the inner nozzle 3 near the communication hole 11.

  Moreover, in the said structure, since the nozzle port 15 of the inner side nozzle 3 is adjoining to the nozzle port 17 of the outer side nozzle 5, the spatter | spatter and return light which scatter from the laser processing position 19 enter into the inner side nozzle 3 easily. There is a problem.

  The present invention has been made in view of the above-described problems, and includes an outer nozzle outside the inner nozzle, an annular assist gas passage provided between the inner nozzle and the outer nozzle, and an inner side of the inner nozzle. A nozzle for a laser processing head provided with a plurality of communication holes in the inner nozzle, the nozzle opening being ejected from each of the communication holes and provided at the tip of the outer nozzle at the base of the assist gas passage An annular pressure adjusting unit is provided for equalizing the flow of the assist gas in the annular gas flow directed toward the head.

  Further, in the laser processing head nozzle, each of the communication holes is provided to face the pressure adjusting portion, and the pressure adjusting portion has an annular shape that forms a constricted portion with the outer peripheral surface of the inner nozzle. The communication holes are provided on the upper side of the step portions.

  In the laser processing head nozzle, the outer diameter of the tip portion of the inner nozzle is larger than the diameter of the nozzle port of the outer nozzle.

  In the laser processing head nozzle, the tip of the inner nozzle is located at a substantially intermediate height position between the pressure adjusting unit and the nozzle opening of the outer nozzle.

  In the laser processing head nozzle, a taper hole having a taper angle larger than a taper angle of the taper hole is provided on a tip end side of the taper hole in the inner nozzle.

  Further, in the laser processing head nozzle, the outer nozzle includes a straight hole communicating with the annular pressure adjusting portion, and a taper hole communicating with the nozzle port is provided below the straight hole. The tip of the nozzle is located in the tapered hole.

  According to the present invention, the flow of the assist gas can be made uniform in the annular assist gas passage between the inner nozzle and the outer nozzle. In addition, it is possible to suppress spatter and return light from entering the inner nozzle.

It is a section explanatory view showing the composition of the nozzle for laser processing heads concerning the embodiment of the present invention. It is sectional explanatory drawing which shows the structure of the nozzle for conventional laser processing heads.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. A laser processing head nozzle (hereinafter simply referred to as a nozzle) 21 according to an embodiment of the present invention is detachably attached to a tip portion of a laser processing head 23. It is attached. The nozzle 21 has a configuration in which an outer nozzle 25 is provided outside the inner nozzle 23 as in the conventional nozzle.

  The inner nozzle 23 includes a fitting portion 29 having a circular outer periphery that is integrally fitted in a fitting hole 27 in the outer nozzle 25. A tapered portion 31 having a progressively smaller diameter on the distal end side (lower end side) is integrally provided at the lower portion of the fitting portion 29. The proximal end outer peripheral portion of the tapered portion 31 and the fitting portion 29 are integrally provided. An annular flat surface portion 33 is formed between the outer peripheral surface and the outer peripheral surface. In the inner nozzle 23, a first tapered hole 35 having a gradually decreasing diameter at the lower end side is formed. A hole 39 is provided.

  The second taper hole 39 serves to temporarily restrict the assist gas flowing in the first taper hole 35 toward the nozzle port 37, and the taper angle of the second taper hole 39 is It is formed larger than the taper angle of the first taper hole 35. Therefore, the assist gas that has flowed in the first tapered hole 35 toward the nozzle opening 37 is rapidly throttled at the position of the second tapered hole 39, and the pressure increases at the portion of the second tapered hole 39, The flow rate of the assist gas ejected from the nozzle port 37 is increased. Therefore, it is possible to more effectively suppress spatter and the like from entering the inner nozzle 23 from the nozzle port 37.

  In the inner nozzle 23, a plurality of communication holes 41 having substantially the same diameter are provided at equal intervals in the circumferential direction at a position close to the proximal end portion of the tapered portion 31.

  In the outer nozzle 25, a medium-diameter straight hole 43 is formed in the lower part of the fitting hole 27, and an annular stepped portion 45 is formed in the lower part of the straight hole 43 so that a small-diameter straight hole is formed. A hole 47 is formed. A tapered hole 51 connected to a nozzle port 49 formed at the tip of the outer nozzle 25 is formed below the straight hole 47.

  The tip of the inner nozzle 23 is in the tapered hole 51 of the outer nozzle 25 and is located at a substantially intermediate height between the stepped portion 45 and the nozzle port 49 and is far away from the nozzle port 49. It is. The outer diameter of the front end surface (tip end) 23F of the inner nozzle 23 is larger than the inner diameter of the nozzle port 49.

  With the above-described configuration, the lower side of the lower flat portion 33 of the inner nozzle 23 is disposed between the inner peripheral surface of the straight hole 43 surrounding the proximal end portion of the tapered portion 31 of the inner nozzle 23. In this configuration, an annular pressure adjusting unit 53 is provided. The communication hole 41 formed in the tapered portion 31 is directed in the direction of the stepped portion 45.

  With the above-described configuration, the assist gas ejected from the communication hole 41 into the pressure adjusting unit 53 as indicated by the arrow A shown in FIG. 1 is generated between the stepped portion 45 and the tapered portion 31 due to the presence of the stepped portion 45. The annular throttle portion 55 formed between the outer circumferential surface and the annular assist gas passage 57 between the tapered portion 31 and the inner circumferential surface of the straight hole 47 is prevented from flowing immediately. Therefore, the assist gas ejected from the communication hole 41 tends to swirl as indicated by the arrow B in the pressure adjusting portion 53, and enters the assist gas passage 57 along the outer peripheral surface of the tapered portion 31. It tends to flow in.

  As understood from the above description, since the assist gas ejected from the communication hole 41 into the pressure adjusting unit 53 is throttled by the action of the throttle unit 55, the pressure is uniformized in the pressure adjusting unit 53. It will be done. Therefore, the flow of the annular assist gas flowing from the throttle portion 55 into the assist gas passage 57 becomes a substantially uniform flow without unevenness.

  As already understood, the communication hole 41 of the inner nozzle 23 is provided on the upper side of the throttle portion 55. Therefore, spatter and the like that tend to scatter from the laser processing position and adhere to the vicinity of the communication hole 41 are more effectively suppressed by the assist gas whose flow velocity is increased in the throttle portion 55, and The rise is suppressed by the swirl flow (flow of arrow B) in the pressure adjusting unit 53. Therefore, it is possible to effectively prevent the spatter and the like from adhering to the vicinity of the communication hole 41 and the outer peripheral surface of the inner nozzle 23.

  The annular flow of the assist gas that has passed through the throttle portion 55 is merged in a merging region 59 between the front end surface 23F of the inner nozzle 23 and the nozzle port 49 of the outer nozzle 25. The junction area 59 is formed in a relatively large space area because the front end surface 23F of the inner nozzle 23 is located at a substantially intermediate height between the pressure adjusting portion 53 and the nozzle port 49 of the outer nozzle 25. It is. Therefore, the assist gas merged from the periphery in the merge region 59 and the assist gas flow ejected from the nozzle port 37 of the inner nozzle 23 are made uniform.

  Therefore, the assist gas ejected from the nozzle port 49 of the outer nozzle 25 has a uniform flow without unevenness. Therefore, even if the advancing direction of the laser cutting process is changed, it is possible to perform blowing off of dross and the like satisfactorily.

  As already understood, at the base of the annular assist gas passage 57 formed between the inner nozzle 23 and the outer nozzle 25, the flow of the assist gas ejected from the communication hole 41 of the inner nozzle 23 is made uniform. An annular pressure adjusting portion 53 is provided.

  Accordingly, the assist gas flow in the assist gas passage 57 can be made uniform, and adhesion of spatter and the like to the peripheral surface of the tapered portion 31 and the vicinity of the communication hole 41 in the inner nozzle 23 is effectively prevented. It is something that can be done.

  In addition, a throttle 55 is provided between the pressure adjuster 53 and the annular assist gas passage 57, and the communication hole 41 provided in the inner nozzle 23 in the direction of the pressure adjuster 53 is configured as described above. It is provided above the diaphragm portion 55. Accordingly, a swirling flow is generated in the pressure adjusting portion 53, and a gas flow tends to be generated along the outer peripheral surface of the tapered portion 31 in the inner nozzle 23. Therefore, it is possible to effectively prevent the adhesion of the spatter and the like to the outer peripheral surface of the tapered portion 31 and the vicinity of the communication hole 41.

  Further, the diameter of the front end surface 23 </ b> F in the inner nozzle 23 is formed larger than the diameter of the nozzle port 49 in the outer nozzle 25. Therefore, it is possible to reduce spatter and the like that tend to scatter from the laser processing position toward the annular assist gas passage 57.

  Further, the height position of the tip portion of the inner nozzle 23 is located at a substantially intermediate height position between the pressure adjusting portion 53 and the nozzle port 49 of the outer nozzle 25. Therefore, the separation distance from the nozzle port 49 to the tip of the inner nozzle 23 is increased. Therefore, the taper angle in the virtual conical shape formed by connecting the laser processing position and the inner peripheral surface of the nozzle opening 37 can be further reduced, and the intrusion and return light such as sputtering into the inner nozzle 23 can be reduced. Intrusion can be reduced.

  In the configuration described above, the second tapered hole 39 having a taper angle larger than the taper angle of the first tapered hole 35 is provided on the distal end side of the first tapered hole 35 in the inner nozzle 23. Therefore, the pressure of the assist gas that flows through the first tapered hole 35 and is ejected from the nozzle port 37 is temporarily increased in the portion of the second tapered hole 39. Therefore, the flow velocity of the assist gas ejected from the nozzle port 37 is increased, and the intrusion of spatter or the like that tends to scatter into the nozzle port 37 can be more effectively suppressed. .

  Further, the outer nozzle 25 is provided with a straight hole 47 below the annular pressure adjusting portion 53, and the tip of the tapered portion 31 in the inner nozzle 23 is inserted into a tapered hole 51 provided below the straight hole 47. The side is located. Therefore, a tapered assist gas passage is formed between the inner peripheral surface of the tapered hole 51 and the outer peripheral surface of the tapered portion 31. Therefore, laminar flow of the assist gas flowing in the direction of the nozzle port 49 of the outer nozzle 25 can be achieved.

21 Nozzle for Leather Processing Head 23 Inner Nozzle 25 Outer Nozzle 31 Tapered Part 35 First Tapered Hole 37 Nozzle Port 39 Second Tapered Hole 41 Communication Hole 45 Stepped Part 49 Nozzle Port 53 Pressure Adjusting Part 55 Restricting Part 57 Assist Gas Passage

Claims (6)

  A laser having an outer nozzle outside the inner nozzle, and a plurality of communication holes that communicate the annular assist gas passage provided between the inner nozzle and the outer nozzle with the inner side of the inner nozzle. A nozzle for a machining head, wherein the flow of an assist gas in an annular gas flow directed to a nozzle port provided at a tip of the outer nozzle is ejected from each communication hole at a base portion of the assist gas passage. A laser processing head nozzle comprising an annular pressure adjusting portion for achieving the purpose.   2. The laser processing head nozzle according to claim 1, wherein each of the communication holes is provided so as to face the pressure adjusting portion, and the pressure adjusting portion includes a throttle portion between the outer peripheral surface of the inner nozzle. A laser processing head nozzle comprising an annular step portion to be formed, wherein each communication hole is provided above the step portion.   3. The laser processing head nozzle according to claim 1, wherein an outer diameter of a tip portion of the inner nozzle is larger than a diameter of the nozzle port of the outer nozzle. 4.   4. The laser processing head nozzle according to claim 1, wherein a tip portion of the inner nozzle is located at a substantially intermediate height position between nozzle openings of the pressure adjusting portion and the outer nozzle. Nozzle for laser processing head.   The laser processing head nozzle according to any one of claims 1 to 4, wherein a tapered hole having a taper angle larger than a taper angle of the tapered hole is provided on a tip end side of the tapered hole in the inner nozzle. Nozzle for laser processing head.   The laser processing head nozzle according to any one of claims 1 to 5, wherein the outer nozzle includes a straight hole communicating with the annular pressure adjusting portion, and communicates with the nozzle port below the straight hole. A nozzle for a laser processing head, comprising: a tapered hole, wherein the tip of the inner nozzle is located in the tapered hole.

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