JP6425678B2 - Processing head of laser processing device - Google Patents

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a processing head of a laser processing apparatus that performs cutting on a workpiece by irradiating a laser beam.

  In the conventional processing head, after introducing the processing gas into the annular flow channel provided in the processing head, the connecting flow channel cross-sectional area leading to the processing head inner space is made narrower than the processing gas supply flow channel cross-sectional area A pressure loss was given to equalize the flow in the annular channel circumferentially.

JP, 2000-225487, A

  In the processing head in such a processing laser device, pressure loss is given by narrowing the connection flow path from the annular flow path provided in the processing head to the processing head inner space. In the case of processing requiring a large flow rate of processing gas, pressure loss is further increased. Further, if the pressure loss is reduced due to the above problems, the flow is not uniformed and becomes unstable in the case of processing such as mild steel oxygen cutting where the flow rate of the processing gas is small.

  The present invention is made in view of the above, and an object of the present invention is to obtain a processing head which can equalize the flow of processing gas regardless of the flow rate of processing gas.

In order to solve the problems described above and to achieve the object, the present invention condenses and irradiates a laser beam to a workpiece through a processing nozzle, and injects a processing gas in a space in a processing head from the processing nozzle to the workpiece A processing head of a laser processing apparatus, which is axially symmetrical with respect to the central axis of a processing nozzle, and has an annular flow path connected to a space in the processing head via a connection flow path and a processing gas in the annular flow path And a processing gas supply channel for supplying the gas. The cross-sectional area of the connection channel is larger than the cross-sectional area of the processing gas supply channel. The processing gas supply flow path is disposed offset with respect to the central axis of the processing nozzle.

  ADVANTAGE OF THE INVENTION According to this invention, it is effective in the ability to equalize the flow of process gas irrespective of the flow volume of process gas.

Sectional drawing which shows the processing head of the laser processing apparatus concerning Embodiment 1 of this invention Sectional view along line II-II in FIG. 1 Sectional view along the line III-III in FIG. 1 Sectional drawing which shows the modification of the processing head of the laser processing apparatus which concerns on Embodiment 1. Sectional drawing which shows the processing gas introduction path in the processing head of the laser processing apparatus concerning Embodiment 2 of this invention Sectional drawing which shows the processing head of the laser processing apparatus concerning Embodiment 3 of this invention Sectional drawing which shows the processing head of the laser processing apparatus concerning Embodiment 4 of this invention Sectional view along line VIII-VIII in FIG. 7 Sectional drawing which shows the processing head of the laser processing apparatus concerning Embodiment 5 of this invention Sectional view along line X-X in FIG. 9 Sectional drawing which shows the processing head of the laser processing apparatus concerning Embodiment 5 of this invention Sectional view along line XII-XII in FIG. Sectional drawing which shows the processing head of the laser processing apparatus concerning Embodiment 7 of this invention Sectional drawing which shows the processing head of the laser processing apparatus concerning Embodiment 8 of this invention Sectional view along line XV-XV in FIG. 14

  Hereinafter, a processing head according to an embodiment of the present invention will be described in detail based on the drawings. The present invention is not limited by the embodiment.

Embodiment 1
FIG. 1 is a cross-sectional view showing a processing head of a laser processing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. The laser beam machine includes a laser oscillator 100 for oscillating the laser beam 3, a processing head 1 for focusing the laser beam 3 on the workpiece 6, and a propagation for guiding the laser beam 3 emitted from the laser oscillator 100 to the processing head 1. An optical system 101 is provided.

  The workpiece 6 is installed on a processing table 9. In addition, although the workpiece 6 is actually installed on the processing table 9 via the support member, illustration of the support member is omitted here.

  The processing head 1 is configured by connecting a nozzle adapter 11 to a head main body 10. The processing nozzle 5 is installed at the tip of the nozzle adapter 11. The processing nozzle 5 is independently replaceable.

  An annular flow passage 12 is provided inside the processing head 1. The annular flow passage 12 is disposed in axial symmetry with respect to the optical axis 2 as shown in FIG. Therefore, the central axis of the annular channel 12 coincides with the optical axis 2. The term "axisymmetric" as used herein includes not only a perfect axisymmetric shape, but also a shape that is substantially axisymmetric even if not completely symmetrical. It can be said that the annular flow passage 12 in which the processing gas supply flow passage 8 described later is disposed at a position offset with respect to the center is substantially axially symmetrical. Further, it can be said that the flow control member or the annular flow path 12 provided with the flow control plate 14 provided with the connection holes 17 described later has a substantially axially symmetrical shape. The annular flow passage 12 is connected to the processing head inner space 15 through the connection flow passage 13. The connecting channel 13 has a narrower cross-sectional area than the annular channel 12.

  As shown in FIG. 2, the processing gas supply passage 8 is disposed at a position offset with respect to the center of the annular passage 12. That is, the center of the annular flow passage 12 is not located on the extension of the processing gas supply flow passage 8.

  As shown in FIG. 1, the laser beam 3 emitted from the laser oscillator 100 is guided along the optical axis 2 by the propagation optical system 101 to the processing lens 4 installed in the processing head 1, and the processing nozzle 5 The light is condensed on the workpiece 6 through the processing nozzle outlet 51. Further, when the processing gas is supplied from the processing gas supply hole 7 installed in the processing head 1 to the annular flow channel 12, the processing gas passes through the annular flow channel 12 to the processing head inner space 15, an annular connected flow The gas is supplied through the passage 13 and then ejected from the processing nozzle outlet 51 to the workpiece 6 in the same manner as the laser beam 3.

  The workpiece is processed by moving at least one of the processing head 1 and the workpiece 6 while supplying the laser beam 3 and the processing gas condensed to the workpiece 6 through the processing nozzle outlet 51 as described above. The relative position between the material 6 and the laser beam 3 can be changed, the machining groove 61 formed in the workpiece 6 is moved and formed, and the laser cutting process is performed. At the time of laser cutting, only the workpiece 6 may be moved by moving the processing table 9 on which the workpiece 6 is installed, or only the processing head 1 may be moved. Furthermore, both the processing table 9 and the processing head 1 may be moved.

  The processing gas used in the laser cutting process uses a small flow rate of oxygen gas for general mild steel, and by using the heat generated by the oxidation reaction in addition to the heat input by the laser, the laser cutting process is performed with high efficiency It is possible to In addition, when the material 6 to be processed is stainless steel, oxygen may be used, but an oxide having a high hardness such as chromium or molybdenum is generated, which makes it difficult to carry out the processing in the subsequent steps. There are many laser cutting processes using. When nitrogen gas is used as the processing gas, processing is performed by blowing away a metal heated and melted by a laser using nitrogen at a high pressure and a large flow rate.

  Since the processing gas supply channel 8 is arranged in a direction offset with respect to the center of the annular channel 12, the processing gas circulates the annular channel 12 centering on the center of the annular channel 12. . In the cross section shown in FIG. 2, when viewed along the traveling direction of the laser beam 3, it is counterclockwise rotated. Therefore, in the annular flow passage 12, the processing gas flows while turning counterclockwise as viewed along the traveling direction of the laser beam 3, and the circumferential flow velocity in the annular flow passage 12 is made uniform and annular It is supplied to the processing head inner space 15 through the connection flow path 13. The processing gas supplied to the processing head inner space 15 is injected from the processing nozzle outlet 51 to the workpiece 6.

  Since the processing gas also swirls in the connection flow channel 13, centrifugal force acts on the processing gas, and the processing gas swirls while being pressed against the outer peripheral surface of the connection flow channel 13. Of the processing gas supplied to the connection flow path 13, the friction increases and decelerates more for the high speed part, while the friction received for the low speed part is smaller, so the circumferential flow velocity becomes more uniform. It will be. Therefore, the processing head 1 according to the first embodiment can suppress the flow into the processing head inner space 15 as it is before the flow velocity in the circumferential direction is equalized, and the processing gas in the connection flow path 13 is The turning component makes the flow of the processing gas uniform. By uniforming the flow of the processing gas, the processing gas is stably discharged from the processing nozzle outlet 51 through the processing head inner space 15, so that laser cutting processing of stable quality can be realized.

  Further, in the processing head 1 according to the first embodiment, it is not necessary to give a pressure loss to make the flow uniform by making the cross sectional area of the connection flow channel 13 narrower than the cross sectional area of the processing gas supply flow channel 8 Therefore, the pressure loss in the connection flow path 13 can be suppressed low. Specifically, by making the cross-sectional area of the connection flow channel 13 having an annular cross section equal to or larger than the cross-sectional area of the processing gas supply flow channel 8, the pressure loss in the connection flow channel 13 can be suppressed low. In particular, by making the cross sectional area of the connection flow channel 13 larger than the cross sectional area of the processing gas supply flow channel 8, the connection flow channel 13 is prevented from becoming a bottleneck in pressure loss, and an excessive pressure loss occurs. Can be suppressed. By avoiding the connection flow path 13 becoming a bottleneck in pressure loss, it becomes possible to lower the processing gas supply pressure. Therefore, a device such as a compressor is not required, and the laser processing device can be configured with an inexpensive system. Further, even when a small amount of processing gas is used as in the case of cutting a mild steel using oxygen as a processing gas, a uniform and stable processing gas can be supplied to the workpiece 6 so that the processing is stable, Therefore, high quality laser cutting can be performed.

In the present embodiment, a CO 2 laser, a fiber laser, a disk laser, a YAG (Yttrium Aluminum Garnet) laser, or a direct diode laser can be applied to the laser oscillator 100, but the invention is not limited thereto. The propagation optical system 101 shown in FIG. 1 is mirror transmission, but may be configured to use a curvature mirror or a lens in the middle. Furthermore, the fiber laser, in the case of a disk laser, YAG laser or direct diode laser, by forming the propagation optical system 101 by an optical fiber, the After guiding the laser beam 3 to the machining head 1, the processing In general, a collimating lens may be provided in the head 1 to be collimated light and then guided to the processing lens 4. Alternatively, the optical system in the processing head 1 may be a zoom lens using two or more lens groups. The laser beam 3 incident on the processing lens 4 does not necessarily have to be collimated, and can be focused on the processing point with a desired beam diameter by controlling the position of the lens system in conjunction.

  In the processing head according to the first embodiment, since the processing gas supply channel 8 is disposed in the direction offset with respect to the center of the annular channel 12, the flow of the processing gas is uniform regardless of the flow rate of the processing gas. Can be

  FIG. 4 is a cross-sectional view showing a modification of the processing head of the laser processing apparatus according to the first embodiment. Inside the processing head 1, a protective glass 20 for protecting the processing lens 4 is provided closer to the processing nozzle 5 than the processing lens 4. The protective glass 20 prevents spatter from being generated from the processing groove 61 of the workpiece 6 at the time of laser processing and adheres to the processing lens 4. The protective glass 20 is particularly effective when using an optical fiber as the propagation optical system 101 and transmitting the laser beam 3 to the processing head 1 by fiber transmission.

Second Embodiment
FIG. 5 is a cross-sectional view showing the processing gas introduction path in the processing head of the laser processing apparatus according to the second embodiment of the present invention. In Embodiment 1, although the case where one processing gas supply hole 7 was shown was shown, you may provide multiple processing gas supply holes. In the second embodiment, the processing head 1 is provided with four processing gas supply holes 71, 72, 73 and 74. In this case, processing gas is introduced into the annular flow passage 12 from four directions. Therefore, as compared with the first embodiment in which the processing gas is introduced from one place, it is possible to form the swirling flow more uniformly, and a more stable processing gas flow can be realized. In the second embodiment, the processing gas is introduced from four directions, but may be two or three directions, or five or more directions.

Third Embodiment
FIG. 6 is a cross-sectional view showing the processing head of the laser processing apparatus according to the third embodiment of the present invention. In the third embodiment, the processing gas supply flow path 8 for supplying the processing gas to the annular flow path 12 disposed in the processing head 1 is offset in the horizontal plane with respect to the annular flow path 12 and It is arranged to be inclined obliquely downward in the paper. In other words, the processing gas supply channel 8 is closer to the tip of the processing head 1 as it goes downstream.

  Since the processing head 1 according to the third embodiment has a velocity component moving away from the connection flow channel 13 when the processing gas is supplied to the connection flow channel 13 through the annular flow channel 12, the processing gas is supplied. As compared with the case where the flow path 8 is disposed in the horizontal direction, the flow in the annular flow path 12 can be facilitated without flowing directly to the connection flow path 13. Therefore, the processing gas flows to the connection flow channel 13 after becoming a more uniform swirling flow than in the case where the processing gas supply flow channel 8 has no inclination, so that a more stable processing gas flow can be realized. .

Fourth Embodiment
FIG. 7 is a cross-sectional view showing the processing head of the laser processing apparatus according to the fourth embodiment of the present invention. FIG. 8 is a cross-sectional view taken along the line VIII-VIII in FIG. In the fourth embodiment, a flow path barrier 16 is provided downstream of the processing gas supply flow path 8 for supplying the processing gas to the annular flow path 12 so that the processing gas does not flow directly to the connection flow path 13. There is.

  According to the fourth embodiment, when the processing gas flows from the processing gas supply flow path 8 to the connection flow path 13 via the annular flow path 12, it is necessary to bypass the flow path barrier 16. For this reason, the processing gas is easily swirled in the annular flow passage 12. Therefore, the processing gas flows into the connection flow channel 13 after becoming a more uniform swirling flow than in the case where the flow channel barrier 16 is not provided, so that a more stable processing gas flow can be realized.

  Furthermore, as in the third embodiment, the processing gas supply channel 8 may be inclined in the opposite direction to the connecting channel 13, and in this case, the processing gas can be more uniformly swirled.

Embodiment 5
FIG. 9 is a cross-sectional view showing a processing head of a laser processing apparatus according to a fifth embodiment of the present invention. FIG. 10 is a cross-sectional view taken along the line X-X in FIG. In the fifth embodiment, a straightening vane 14 which is a straightening member for dividing the connecting flow passage 13 in the circumferential direction of the optical axis 2 is disposed in parallel with the optical axis 2 in the connecting flow passage 13 having an annular cross section. There is.

  In the first to fourth embodiments, the processing gas is supplied to the annular flow channel 12 through the processing gas supply hole 7 and the processing gas supply flow channel 8 provided at a position offset from the center of the annular flow channel 12. Ru. Therefore, the processing gas swirls in the annular flow channel 12, and the circumferential swirl component becomes substantially uniform in the annular flow channel 12, and then flows into the connection flow channel 13, and the processing gas having passed through the connection flow channel 13 is processed It has been stably supplied to the workpiece 6 through the in-head space 15 and the processing nozzle outlet 51. Therefore, the stability and straightness of the processing gas are excellent, and stable and good cutting can be realized.

  However, the processing gas holds the turning component even in the processing groove 61 formed in the workpiece 6 by laser processing. Therefore, in the first to fourth embodiments described above, the processing gas flows in the same direction as the swirl component in the advancing direction of the laser processing, and the end face to which the supply of the processing gas is weak and the advancing direction of the laser processing Since the processing gas flows in the opposite direction and the end face where the supply of the processing gas is strongly applied can be made, the surfaces on both sides of the processing groove 61 are processed with different surface quality.

  In general laser cutting, when cutting out the target shape from the workpiece 6, the target shape is a product, and the remaining end surface members are not products. Therefore, in this case, the processing direction is set so that the surface quality of the member left as a product in the turning direction of the processing gas becomes better. However, depending on processing, the left end side members may also be products, and if a turning component is present in the processing gas in the processing groove 61 after coming out of the processing nozzle outlet 51, the cut end surfaces of both members On the other hand, the same surface quality can not be obtained.

  In the fifth embodiment, since the straightening vanes 14 are disposed in the connection flow path 13, the processing gas swirling in the annular flow path 12 and in the annular connection flow path 13 is not discharged into the processing head inner space 15. , And strikes a rectifying plate 14 parallel to the optical axis 2. Therefore, the processing gas is rectified by flowing along the rectifying plate 14, and the swirl component of the processing gas is suppressed. From this, in the processing head inner space 15, the processing nozzle outlet 51 and the processing groove 61 on the downstream side of the straightening vane 14, the processing gas has a stable flow with no swirling component. Can be achieved. In the fifth embodiment, it is not necessary to narrow the cross-sectional area of the connection flow path 13 in the portion where the straightening vane 14 is installed. Therefore, uniform flow in the circumferential direction can be realized with low pressure loss.

  The rectifying plate 14 does not necessarily have to be parallel to the optical axis 2, but if the rectifying plate 14 is inclined with respect to the optical axis 2, the flow of the processing gas swirling in the connection flow path 13 Depending on the direction, the pressure loss may increase and may also cause a new turning component to be generated. If the straightening vane 14 is installed parallel to the optical axis 2, the pressure loss is unlikely to become the cause of extreme increase regardless of how the flow rate and flow velocity of the processing gas change, and the turning component is suppressed. The laser processing conditions can be made less likely to be restricted.

Sixth Embodiment
FIG. 11 is a cross-sectional view showing a processing head of a laser processing apparatus according to a fifth embodiment of the present invention, and FIG. 12 is a cross-sectional view along line XII-XII in FIG. In the sixth embodiment, instead of the rectifying plate 14 shown in the fifth embodiment, a rectifying member provided with a connecting hole 17 is disposed in the middle of the connecting flow channel 13, and the connecting flow channel 13 has a circumference of the optical axis 2. It is divided in the direction. The connection hole 17 is opened in parallel with the optical axis 2. Further, the total cross-sectional area of the connection hole 17 is larger than the cross-sectional area of the processing gas supply hole 7 so that excessive pressure loss in the connection hole 17 does not occur. As shown in FIG. 12, the cross section of the connection flow path 13 divided by the flow straightening member is circular.

  The processing head according to the sixth embodiment suppresses the turning component of the processing gas because it is rectified in the direction of the hole disposed parallel to the optical axis 2 when passing through the connection hole 17 including the turning component. be able to. In addition, when the connection hole 17 is too short with respect to the diameter of the connection hole 17, the effect of suppressing the swirl component of the flow of processing gas becomes small, but the hole having a length of 10 times or more with respect to the diameter turns It is known experimentally that the effect of suppressing ingredients can be obtained. Therefore, by making the length of the connection hole 17 10 times or more of the diameter of the connection hole 17, it is possible to further suppress the turning component, and to realize a more stable and directional-free good cutting. Can.

Embodiment 7
FIG. 13 is a cross-sectional view showing a processing head of a laser processing apparatus according to a seventh embodiment of the present invention. In the first to sixth embodiments, the connecting flow channel 13 is installed from the annular flow channel 12 to the processing head inner space 15 in the direction of the processing lens 4, for example, upward in FIG. On the other hand, in the seventh embodiment, the connection flow path 13 is installed with the processing nozzle 5 facing the direction. Further, as in the fourth embodiment, a flow path barrier 16 is provided in the annular flow path 12 so that the processing gas does not flow directly to the connection flow path 13.

  According to the configuration of the seventh embodiment, when processing gas is supplied to the connection flow channel 13 via the annular flow channel 12, it is necessary to bypass the flow channel barrier 16, so the inside of the annular flow channel 12 is swirled. This facilitates the formation of a more uniform swirling flow. Further, even when flowing to the connection flow path 13, it is possible to realize a more stable processing gas flow.

  When the shape of the connection flow path 13 from the annular flow path 12 to the processing head inner space 15 is annular, the processing gas supplied from the processing nozzle outlet 51 to the workpiece 6 has a swirl component and the swirl component is It becomes possible to maintain and process.

Eighth Embodiment
FIG. 14 is a cross-sectional view showing a processing head of a laser processing apparatus according to an eighth embodiment of the present invention. FIG. 15 is a cross-sectional view taken along the line XV-XV in FIG. In the case of suppressing the turning component of the processing gas in order to obtain processing without directivity to the processing groove 61 as described in Embodiment 5 with respect to Embodiment 7, connection is performed as shown in FIG. A straightening vane 14 in a direction parallel to the optical axis 2 may be disposed in the flow path 13.

  As described in the fifth embodiment, the flow of the processing gas having the swirl component flowing into the connection flow path 13 flows along the flow straightening plate 14 by colliding with the flow straightening plate 14 parallel to the optical axis 2. By providing the rectifying plate 14, the swirl component of the processing gas can be suppressed. From this, in the processing head inner space 15, the processing nozzle outlet 51 and the processing groove 61 on the downstream side of the straightening vane 14, the processing gas has a stable flow with no swirling component. Can be achieved. In the fifth embodiment, it is not necessary to narrow the cross-sectional area of the connection flow path 13 in the portion where the straightening vane 14 is installed. Thus, it is possible to realize circumferentially uniform flow with low pressure loss.

  As described in the sixth embodiment, the pivoting component can also be suppressed by configuring the connecting flow channel 13 with a plurality of holes parallel to the optical axis 2.

  The configuration shown in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and one of the configurations is possible within the scope of the present invention. Parts can be omitted or changed.

  DESCRIPTION OF SYMBOLS 1 processing head, 2 optical axis, 3 laser beam, 4 processing lens, 5 processing nozzle, 6 processed material, 7, 71, 72, 73, 74 processing gas supply hole, 8 processing gas supply flow path, 9 processing table, DESCRIPTION OF SYMBOLS 10 Head main body, 11 nozzle adapter, 12 annular flow path, 13 connection flow path, 14 flow regulating plate, 15 processing head internal space, 16 flow path barrier, 17 connection hole, 20 protective glass, 51 processing nozzle outlet, 61 processing groove, 100 laser oscillator, 101 propagation optics.

Claims (6)

A processing head of a laser processing apparatus for condensing and irradiating a laser beam onto a workpiece through a processing nozzle and injecting a processing gas in a space in a processing head from the processing nozzle to the workpiece.
An annular flow channel which is axially symmetrical with respect to the central axis of the processing nozzle, and is connected to the processing head inner space via a connection flow channel;
And a processing gas supply flow path for supplying the processing gas to the annular flow path,
The cross-sectional area of the connection channel is larger than the cross-sectional area of the processing gas supply channel,
A processing head of a laser processing apparatus, wherein the processing gas supply flow path is disposed offset with respect to a central axis of the processing nozzle. Having a plurality of the processing gas supply channels,
The processing head of the laser processing apparatus according to claim 1, wherein the processing gas supply flow paths are installed in directions different from each other with respect to the central axis. The processing head of the laser processing apparatus according to claim 1 or 2 , wherein the processing gas supply flow channel is installed in a direction away from the inlet to the connection flow channel from the annular flow channel. The processing head of the laser processing apparatus according to any one of claims 1 to 3 , further comprising a flow path barrier between the downstream outlet of the processing gas supply flow path and the connection flow path. The processing head of the laser processing apparatus according to any one of claims 1 to 4 , further comprising: a straightening member that divides the connection flow path in the circumferential direction of the central axis. The processing head of the laser processing apparatus according to claim 5 , wherein a cross-sectional shape of the connection flow channel divided by the flow straightening member is circular.

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