JP6162014B2 - Laser processing head - Google Patents

Description

  The present invention prevents or reduces spatter generated from a processing part from adhering to a condensing lens when performing target processing by irradiating laser light toward a workpiece and injecting assist gas. The present invention relates to a laser processing head that can be used.

  A laser processing method may be employed when cutting or welding a workpiece made of metal. In this laser processing method, a laser beam is irradiated from a laser processing head toward a workpiece, and an assist gas is jetted to remove a melt or vapor generated from the base material with the assist gas, or Cutting or welding is performed by relatively moving the laser processing head and the workpiece while protecting the molten state with the assist gas.

  The laser processing head has a processing head main body provided with a condensing lens for condensing laser light at the upper portion and an opening through which the laser light and assist gas pass at the lower portion. Further, a supply port for supplying an assist gas is provided on a side surface of the processing head body, and an assist gas selected from oxygen gas, air, nitrogen gas, or the like is supplied according to the target processing. The opening provided in the lower part of the processing head main body may be any diameter that allows laser light to pass through, and generally has a relatively small area. Further, the assist gas supply port provided on the side surface of the processing head main body is set in consideration of processability, and the area is generally large.

  When laser processing is performed, a part of the molten base material is scattered as spatter and adheres to the outer peripheral surface of the processing head body or enters the inside of the processing head body against the assist gas injected from the opening. May adhere to the condenser lens. If spatter adheres to the condensing lens, the energy of the laser beam is absorbed by the spatter and may cause damage to the condensing lens. For the purpose of preventing spatter from adhering to the condensing lens, The technology has been proposed.

  For example, the invention described in Patent Document 1 has a processing head body in which a protective lens is provided between a condenser lens and a laser nozzle. The processing head body is provided with an air blowing nozzle for protecting the protective lens with an air curtain, and a removable air curtain cover is provided at an opposing position. The assist gas is configured to be ejected coaxially with the laser beam from an assist gas ejection port provided on the laser nozzle side of the air blowing nozzle.

  In the invention described in Patent Document 1, an air curtain composed of a high-speed air flow and an assist gas having a flow velocity suitable for laser processing work independently, so that while improving the shielding performance against the processing site, the sputter is achieved. Can be prevented from being rolled up.

  The invention described in Patent Document 2 relates to a processing head of a fiber laser processing machine that can protect an optical element, and a trap member is provided between a lens unit and a nozzle provided in the head body, The assist gas is configured to increase in speed when passing through the throttle portion formed in the trap member, thereby preventing dust from entering, and capturing the dust in the stay trap portion formed in the trap member.

  In the invention described in Patent Document 2, when dust enters from the nozzle, even if the dust travels in the direction of the lens unit, it is blocked by the increased assist gas flow, and is dropped and trapped in the stay trap. For this reason, the dust of a lens unit does not adhere.

JP 09-220687 A JP 2012-024811 A

  In the invention described in Patent Document 1, air and assist gas are simultaneously injected to form an air curtain inside the processing head main body. In particular, the air forming the air curtain needs to have a high flow velocity and is injected at a pressure higher than that of the assist gas. For this reason, there exists a possibility that air may mix in assist gas and a mixed gas may be injected from a laser nozzle, and in this case, there exists a possibility that the shielding performance by assist gas with respect to a process site | part may be inhibited.

  Moreover, in the invention described in Patent Document 2, the assist gas continuously passes through the constricted portion formed in the trap member and the stay trapping portion having an enlarged diameter, and the flow is disturbed as the cross-sectional area changes. In this case, there is a possibility that the assist gas injected from the nozzle is not stable and the quality of the processed part becomes unstable.

  An object of the present invention is to provide a laser processing head capable of preventing or reducing the spatter from reaching the condenser lens by the assist gas even when spatter enters from the irradiation port provided in the processing head main body. There is to do.

  The present inventor has been developing to prevent spatter that has entered the inside of the processing head body from reaching the condenser lens. As a result, in order to prevent the spatter from adhering to the condensing lens, it has been found that it is effective to form a flow obliquely downward across the optical axis of the laser beam. Further, it has been found that it is preferable to prevent the increase of the sputtering by colliding the assist gas having an increased flow velocity inside the machining head main body with the sputtering.

Based on the above results, the laser processing head according to the present invention performs laser processing that irradiates the workpiece with the laser beam condensed by the condensing lens provided on the upper part of the processing head body from the irradiation port provided on the lower part together with the assist gas. An assist gas injection member is provided on a side surface of the processing head main body between a condensing lens provided at an upper portion and an irradiation port provided at a lower portion. and by the condensing lens that is configured to be injected in a direction tilted in and irradiation direction downstream side across the optical axis of the laser light irradiated from the irradiation port it is condensed.

In the laser processing head, an injection port for injecting an assist gas is formed at a tip of the assist gas injection member, and an opening area of the injection port is an irradiation provided at a lower portion of the processing head main body. not smaller than the opening area of the mouth.

In the upper sharp over The processing head, the assist gas jetting member, the assist gas, flat dimension is large dimension along the optical axis of the laser beam traverses the optical axis of the small laser beam In order to inject the nozzle into a flat shape or a plurality of small holes, or a side surface of the processing head main body that is 90 degrees in plan view centered on the optical axis of the laser beam. It is preferable that a plurality are provided within the range.

  In the laser processing head according to the present invention, an assist gas injection member is provided on the side surface of the processing head main body and between the condenser lens and the irradiation port. In particular, the assist gas injection member is configured to inject the assist gas by inclining the assist gas across the optical axis of the laser beam to the downstream side in the irradiation direction, so that the sputter entering the inside of the processing head main body from the irradiation port. Can be sprayed obliquely from above. For this reason, it becomes possible to push out the movement of the laser beam while preventing the movement of the spatter from rising, and it is possible to prevent or reduce adhesion of the laser beam to the condenser lens.

  In particular, in order to ensure the flow rate of the assist gas injected from the irradiation port, the opening area of the injection port for injecting the assist gas formed at the tip of the assist gas injection member is smaller than the opening area of the irradiation port It is necessary to increase the pressure of the assist gas supplied to the injection port. For this reason, it is possible to realize a fast flow of the assist gas inside the processing head main body, and this assist gas acts as a large resistance against the sputter entering from the irradiation port. Accordingly, it is possible to prevent or reduce adhesion of the laser beam to the condenser lens by preventing the laser beam from rising inside the processing head while pushing the laser beam to the outside of the optical axis.

  Further, the assist gas injection member is formed with a flat injection port or an injection port composed of a plurality of small holes, or the planar view centered on the optical axis of the laser beam is within a range of 90 degrees. By providing a plurality, even when spatter that has entered the inside of the processing head body from the irradiation port diffuses, it is pushed out of the optical axis of the laser beam while preventing the rise of these spatters to the condenser lens. Can be prevented or reduced.

It is a figure explaining the structure of the laser processing head which concerns on 1st Example. It is an external view explaining the structure of the laser processing head which concerns on 2nd Example. It is a figure explaining the structure of the laser processing head which concerns on 2nd Example, and is III-III sectional drawing of FIG. It is a figure explaining the structure of the laser processing head which concerns on 3rd Example.

  Hereinafter, a laser processing head according to the present invention will be described. In the laser processing head according to the present invention, the assist gas is ejected in a direction that crosses the optical axis of the laser beam and is inclined downstream in the laser beam irradiation direction by the assist gas injection member provided in the processing head body. It is configured as follows. For this reason, it becomes possible to spray the assist gas obliquely from above on the spatter that has occurred when the workpiece is welded or cut and enters the inside of the processing head main body. As a result, it is possible to prevent or reduce adhesion of the laser beam to the condenser lens by pushing the laser beam outward while preventing the spatter from rising.

  The configuration of the laser processing head according to the first embodiment will be described with reference to FIG. The laser processing head A shown in the figure has a processing head main body 1 provided with a condenser lens 2 in the upper part and provided with an irradiation port 3 for irradiating laser light and injecting assist gas at the lower part. The center of the condenser lens 2 and the center of the irradiation port 3 are linearly connected, and this straight line coincides with the optical axis 4 a of the laser light 4.

  The processing head main body 1 is formed as a cylindrical tube portion 1a on the upper side where the condenser lens 2 is provided, and is formed as a tapered portion 1b whose diameter decreases downwardly following the tube portion 1a. ing. And the nozzle 3a in which the irradiation port 3 was formed in the center at the lower end part of the taper part 1b is attached so that attachment or detachment is possible. For this reason, it is possible to selectively attach different nozzles 3a formed with irradiation ports 3 of different diameters to the processing head main body 1, and it is possible to apply to laser oscillators having different outputs.

  An assist gas injection member 5 having an assist gas injection port 6 is provided between the condenser lens 2 and the irradiation port 3 in the cylindrical portion 1 a of the processing head main body 1. The assist gas injection member 5 is configured to inject the assist gas so as to incline in a direction that traverses the optical axis 4 a of the laser beam 4 and that is directed downstream in the irradiation direction of the laser beam 4. The assist gas injection member 5 only needs to be able to inject the assist gas as described above, and does not limit the structure or shape.

  In the present embodiment, the assist gas injection member 5 is arranged substantially perpendicular to the cylindrical portion 1a of the processing head main body 1 and is configured to be detachable. When the assist gas injection member 5 is attached to the cylindrical portion 1a, one end surface (front end surface 5a) is disposed inside the processing head main body 1, and the other end portion (rear end portion 5b) is the processing head main body 1. Placed outside. Further, the assist gas injection member 5 is formed with a hole 5c having a large diameter from the rear end portion 5b toward the front end surface 5a. The hole 5c is formed up to a position reaching the back side of the tip surface 5a without penetrating the tip surface 5a, and is connected to an assist gas supply source (not shown).

  The front end surface 5a of the assist gas injection member 5 is configured as an inclined surface inclined with respect to the central axis of the assist gas injection member 5, and an assist gas injection port 6 is formed substantially perpendicular to the front end surface 5a. Has been. Accordingly, the injection port 6 is inclined with respect to the central axis of the assist gas injection member 5, and the assist gas injection member 5 is directional. For this reason, it is preferable to form a mark (not shown) on either side of the rear end portion 5b of the assist gas injection member 5 in order to indicate the injection direction of the injection port 6.

  The assist gas injection member 5 is attached to the cylindrical portion 1a of the processing head main body 1 in a state in which the center axis 6a of the injection port 6 is set in a posture so as to face down across the optical axis 4a of the laser light 4. . The angle formed by the ejection port 6 and the optical axis 4a is not particularly limited. However, when the central axis 6a of the injection port 6 intersects the tapered portion 1b of the machining head main body 1, each of the central axis 6a and the inner surface of the tapered portion 1b in the direction of the irradiation port 3 is preferably an obtuse angle. That is, the inclination is preferably such that the assist gas refracted in the direction of the irradiation port 3 when the assist gas injected from the injection port 6 collides with the inner surface of the tapered portion 1b.

  The diameter (opening area) of the injection port 6 for injecting the assist gas is not particularly limited. However, it is preferably smaller than the opening area of the irradiation port 3. In particular, since the diameter of the irradiation port 3 can be changed by selecting the nozzle 3a, a plurality of assist gas injection members 5 in which the injection ports 6 having different diameters are prepared are prepared. It is preferable to select and install according to the diameter.

  In the processing head main body 1 configured as described above, the opening area of the injection port 6 is smaller than the opening area of the irradiation port 3, so that the assist gas supply pressure Po supplied to the hole 5 c of the assist gas injection member 5 A pressure difference (Po> Pi) is generated between the internal pressure Pi of the machining head main body 1 supplied through the ejection port 6. Further, a pressure difference (Po> Pi> P) is also generated between the internal pressure Pi of the processing head body 1 and the atmospheric pressure P acting via the irradiation port 3.

  For this reason, the flow of the assist gas according to the difference between the supply pressure Po of the assist gas and the internal pressure Pi of the processing head body 1 is generated inside the processing head body 1. At this time, the flow velocity of the assist gas in the machining head main body 1 is sufficiently larger than the flow velocity of the assist gas in the conventional machining head.

  In the case of the conventional machining head, the diameter of the member connecting the assist gas supply source and the machining head is large, and there is almost no difference between the assist gas supply pressure and the internal pressure of the machining head body (Po = Pi). ). Thus, the assist gas in the processing head is in a pressurized state (Po), and the cross-sectional area of the processing head is sufficiently larger than the cross-sectional area of the irradiation port. For this reason, when the assist gas is injected from the irradiation port, the flow velocity of the assist gas in the machining head is small.

  That is, the assist gas flow rate inside the machining head main body 1 of the laser machining head A can be made higher than the conventional flow velocity, and this velocity energy is resisted against the spatter entering the machining head 1. It is possible to act as. In particular, since the assist gas injected from the injection port 6 is inclined toward the downstream side in the irradiation direction of the laser beam 4, the assist gas acts on the rising sputtering from an obliquely upward direction, and the sputtering is surely performed. Can be prevented from rising.

  The assist gas ejected from the ejection port 6 crosses the optical axis 4 a of the laser beam 4, collides with the tapered portion 1 b of the opposing processing head body 1, and is refracted in the direction of the irradiation port 3. It is sprayed from the irradiation port 3 to the target processing site, and it is possible to proceed with the target processing including welding or cutting.

  Next, the configuration of the laser processing head B according to the second embodiment will be described with reference to FIGS. In the present embodiment, the same parts as those in the first embodiment and the parts having the same functions are denoted by the same reference numerals, and the description thereof is omitted (the same applies hereinafter).

  The laser processing head B according to the present embodiment is configured by arranging two assist gas injection members 5 on the processing head main body 1 side by side in a substantially horizontal direction. As shown in FIG. 3, each assist gas injection member 5 is in a plane around the optical axis 4a of the laser beam 4 so that the assist gas can be injected across the optical axis 4a of the laser beam 4. Are arranged so as to be within a range of 90 degrees. For this reason, the assist gas injected from the injection ports 6 of the two assist gas injection members 5 has a small dimension in the direction (longitudinal direction) along the optical axis 4a of the laser light 4 and a direction crossing the optical axis 4a ( It is injected in a flat shape with a large dimension in the horizontal direction.

  Thus, by ejecting the assist gas in a flat shape, it becomes possible to reliably protect the entire area of the surface of the condenser lens 2 by the assist gas.

  In order to inject the assist gas in a flat shape, the tip portion of the assist gas injection member is formed flat, in addition to arranging the two assist gas injection members 5 in a substantially horizontal direction as in the second embodiment. In addition, a flat injection port may be formed at the tip portion. In this case, it is possible to configure by pressing the tip portion of the assist gas injection member in which the injection port is formed in advance. Moreover, after forming the front-end | tip part of an assist gas injection member flat, you may form a some small hole from the front end surface side along a flatness.

  Next, the configuration of the laser processing head C according to the third embodiment will be described with reference to FIG. In this embodiment, the laser processing head C is configured by arranging two assist gas injection members 5 in the vertical direction along the optical axis 4 a of the laser light 4. As described above, by arranging the flow of the assist gas in the vertical direction, it becomes possible to act the resistance by the assist gas twice on the sputter entering the inside from the irradiation port 3 of the processing head body 1. It is possible to effectively prevent the increase in spatter.

  With the laser processing head of the present invention configured as described above, it is possible to prevent or reduce spatter adhesion to the condenser lens, and it is possible to cope with either cutting or welding.

A, B, C Laser processing head 1 Processing head body 1a Tube portion 1b Tapered portion 2 Condensing lens 3 Irradiation port 3a Nozzle 4 Laser light 4a Optical axis 5 Assist gas injection member 5a Front end surface 5b Rear end portion 5c Hole 6 Injection port 6a Center axis

Claims (3)

A laser processing head for irradiating a workpiece with a laser beam condensed by a condensing lens provided on the upper part of the processing head body from an irradiation port provided on the lower side together with an assist gas,
On the side surface of the processing head main body, an assist gas injection member is provided between the condenser lens provided in the upper part and the irradiation port provided in the lower part.
The assist gas injection member is configured to inject the assist gas in a direction that crosses the optical axis of the laser light that is collected by the condenser lens and is irradiated from the irradiation port and is inclined downstream in the irradiation direction. The injection port for injecting assist gas is formed in the tip , and the opening area of the injection port is smaller than the opening area of the irradiation port provided in the lower part of the processing head body. Laser processing head.   The assist gas injection member is formed in a flat shape in order to inject the assist gas into a flat shape having a small size in the direction along the optical axis of the laser light and a large size in the direction crossing the optical axis of the laser light. The laser processing head according to claim 1, wherein the laser processing head has an injection port comprising a plurality of small holes.   2. The laser according to claim 1, wherein a plurality of the assist gas injection members are provided in a range of 90 degrees on a side surface of the processing head main body and centered on the optical axis of the laser beam. Processing head.

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