JP3532223B2 - Laser processing machine head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing head of a laser processing machine, and more particularly, to a laser processing machine having a nozzle characterized by ejection of a cooling medium and assist gas. This relates to the machining head. 2. Description of the Related Art As is well known in the past, a laser processing apparatus for processing a plate-shaped workpiece has a reflecting mirror for irradiating the workpiece with a laser beam from a laser oscillator. A processing head having a condensing lens for condensing the laser beam and a processing table for horizontally supporting and moving the workpiece are provided. In laser processing, a laser beam is oscillated from a laser oscillator and irradiated onto a workpiece together with an assist gas from a processing head. The assist gas reacts with the work material to help melt the work material and removes molten metal and slug. In addition, there is also an effect of protecting the condenser lens from the scattering of the molten metal. In cutting with a laser beam,
The energy of the laser beam irradiated intensively on the processing point of the workpiece is absorbed by the workpiece as thermal energy,
The workpiece is melted and cut by this thermal energy. Accordingly, in order to perform accurate cutting, it is necessary to narrow the heat-affected portion. Therefore, in such thermal processing cutting, cooling is particularly performed as a cooling means for the workpiece during cutting of a thick plate. Highly effective water spray is used. This water spraying is performed by ejecting a laser beam and an assist gas coaxially from an inner nozzle of a nozzle having a double structure and flowing water from the outer nozzle. Therefore, the water flowing out from the outer nozzle is entrained by the assist gas ejected from the inner nozzle to become a fog state, and is sprayed on the workpiece together with the assist gas. In thick plate processing, the larger the inner nozzle diameter and the longer the straight portion of the gas blowing portion at the tip of the nozzle, the better the direction of the assist gas ejected from the nozzle and the better the cut surface. It has been known. However, in such a conventional technique, the assist gas ejected from the inner nozzle has a relative velocity with respect to the atmosphere when ejected alone. Immediately after the eruption, the flow is disturbed.
This disturbance in direction begins from the outer periphery of the assist gas,
Since it progresses inward, increasing the nozzle diameter delays the occurrence of turbulence inside the assist gas, and depending on the assist gas pressure and other factors, less turbulent assist gas blows into the cross-section groove, There is a problem that the consumption amount of the assist gas increases and the running cost is deteriorated. Further, the streak generated on the cut surface is generated when the work material melted by the laser beam is cooled and solidified by the assist gas, so that if the assist gas flow is disturbed, it enters the cutting groove. There is a possibility that the amount of gas and the flow velocity are reduced, and molten metal adheres to the back surface or the streak is disturbed. And since water flowing out from the outer nozzle is entrained by the assist gas and becomes a mist state and sprayed on the processed portion of the workpiece, the processing stability is ensured well, but the heat loss is large and the processing speed is high. The thickness of the workable plate is reduced. Furthermore, increasing the length of the straight portion at the tip of the inner nozzle has the effect of preventing disturbance of the assist gas flow, but there is a problem that the laser beam is likely to interfere and the focal point and movable range are shortened. An object of the present invention has been made by paying attention to such a conventional technique, and is capable of improving cutting ability, cutting surface roughness and processing stability, and reducing running cost. It is to provide a processing head of a processing machine. The present invention has been made in view of the conventional problems as described above. The present invention has been made around the inner nozzle that emits an assist gas to a workpiece and irradiates a laser beam. An outer nozzle that ejects a shielding gas mixed with a cooling medium is configured, and the ejection speed of the shielding gas from the outer nozzle is configured to be substantially the same as the ejection speed of the assist gas from the inner nozzle, and the inner nozzle The outer nose so that the relative height can be adjusted.
It is the structure which provided the robot movably up and down . A preferred embodiment of the present invention will be described below with reference to the drawings. 5 and 6 show the entire laser beam machine 1. FIG. This laser beam machine 1 includes a base 3, a post 5 fixed to one end of the base 3 and formed vertically, and an overhead beam 7 supported by the post 5 in a horizontal cantilever shape above the base 3. An NC control device 9 for numerically controlling the laser processing machine 1 is provided on the front surface (lower side in FIG. 6) of the post 5. A plurality of free bear balls 11 are placed on the upper end of the base 3 in order to place a workpiece W to be processed horizontally.
A fixed table 13 is provided. A processing head 19 having a mirror assembly 15 and a condenser lens 17 is provided at the front end of the overhead beam 7. A nozzle 21 for irradiating the laser beam LB is provided at the tip (lower end) of the processing head 19. The mirror assembly 15 includes a laser oscillator 2 provided on the left side of the laser processing machine 1 in the drawing.
3 is refracted in the direction of the condenser lens 17 and the workpiece W, and mirror assemblies 25 and 25 for sending the laser beam 23 from the laser oscillator 23 to the mirror assembly 15 are provided. . Accordingly, such a laser processing machine 1 receives the laser beam LB from the laser oscillator 23 and irradiates the laser beam LB through the processing head 19 for processing the workpiece W. On the other hand, in order to supply and position the workpiece W, a horizontally movable carriage base 27 and a pair of workpieces provided on the carriage base 27 so as to be movable and grip the workpiece W. A carriage 31 having a clamp 29 is provided. Carriage base 27 is fixed table 13.
Is integrally formed with a movable table 33 provided on both sides of the fixed table 13 and is slidably provided on a pair of guide rails 35 provided in parallel on both sides of the fixed table 13. It can be moved and positioned in any direction. The carriage 31 is provided on the carriage base 27 so as to be movable and positionable in the X-axis direction. Accordingly, the workpiece W is positioned in the machining area located directly under the machining head 19 in the carriage 3 equipped with the work clamp 29 for clamping the workpiece W.
1 is controlled to move in the X direction on the carriage base 27,
Further, the carriage base 27 is moved and controlled along the guide rail 35 in the Y direction. Next, the machining head 19 will be described with reference to FIG. The processing head 19 is provided with a condensing lens 17 for condensing the laser beam LB on the upper side of the central portion. An assist gas ejection port 37 that ejects the assist gas AG is provided. An inner nozzle 39 that irradiates the workpiece W with the laser beam LB and ejects the assist gas AG toward the workpiece W directly below the condenser lens 17 at the center of the lower end of the machining head 19.
Is provided. On the outer periphery of the inner nozzle 39, for example, an outer nozzle 41 for ejecting a shielding gas SG such as air and water WA as a cooling medium is provided. The outer nozzle 41 has an outer nozzle space 41A continuous along the shape of the inner space G, and is connected to the pipe 43 at the upper end of the outer nozzle space 41A. The lower end of the outer nozzle space 41 </ b> A forms a circular groove on the lower end surface of the nozzle 21 to form the outer nozzle 41.
The pipe 43 connected to the outer nozzle 41 is provided with a mixer 45 for mixing the mist-like water WA into the shield gas SG that has been sent. In the machining head 19 constructed as described above, the laser beam LB sent from the laser oscillator 23 via the mirror assembly 15 is reflected by the condenser lens 17.
The workpiece W is irradiated by the inner nozzle 39 to the cut portion of the workpiece W, and the assist gas AG is ejected toward the workpiece W to cut the workpiece W. At this time, the shield gas SG mixed with the mist-like water WA by the mixer 45 is ejected from the outer nozzle 41 at substantially the same flow rate as the assist gas AG. Referring to FIG. 2, when the shielding gas SG is ejected from the outer nozzle 41 as described above, the assist gas AG ejected from the inner nozzle 39 is not the atmosphere,
It will have a relative speed with the shield gas SG,
As a result, the relative speed is reduced. For this reason, the flow of the assist gas AG is not disturbed by the shielding effect of the shielding gas SG, and a large amount of gas having good directivity is blown into the processing portion. Therefore, the piercing time is shortened and the cut surface roughness is improved, so that the kerf is improved. The width can be narrowed, and the processing speed can be further increased. The shield gas SG includes a mixer 45.
Since the mist-like water WA is previously mixed, the effect of cooling the heat generated in the workpiece W by cutting can be enhanced. Here, since the flow rate of the shield gas SG substantially matches the flow rate of the assist gas AG, the shield gas S
The speed at which the mist-like water WA mixed in G enters the assist gas AG is slow and is not directly blown onto the processing part, so that the loss of the laser beam LB due to the water WA does not occur, and the processing speed can be reduced. Absent. Furthermore, since there is little mixing of the shielding gas SG and the assist gas AG after jetting the nozzle, inexpensive air or the like can be used as the shielding gas SG. Since the shield gas SG is separate from the assist gas AG, the flow rate or gas pressure can be set separately. For example, if the shielding gas SG is increased, it is possible to prevent the condensing lens from being contaminated by sputtering that occurs during piercing. As shown in FIG. 3, the outer nozzle 41 is provided so as to be movable in the vertical direction so that the relative height with respect to the inner nozzle 39 can be adjusted.
If controlled by the C device, the shield gas SG
It is also possible to change the cooling range according to the machining shape. That is, as shown on the right side of the figure, the outer nozzle 41
Is raised relative to the inner nozzle 39, the shielding gas SG spreads over a wide range, and thus the cooling range widens. The left side in the figure shows a case where the lower end of the outer nozzle 41 is at the same height as the lower end of the inner nozzle 39. In the above embodiment, the outer nozzle 41 is provided on the outer periphery of the inner nozzle 39. As shown in FIG. 4, the nozzle outlets of the outer nozzle are not ring-shaped but small holes arranged at equal intervals. 47 may be sufficient. Furthermore, instead of the shielding gas SG, water W
A or oil can be directly ejected, or oil, gas or a mixed gas thereof cooled by an external cooling device can also be used. As can be understood from the above description of the embodiment, the present invention has a jet speed of the assist gas jetted from the inner nozzle 39 and a jet speed of the shield gas from the outer nozzle 41. Since the speed difference between the assist gas and the shield gas is small, laser processing can be performed while preventing disturbance of the assist gas flow. Therefore, the cooling medium contained in the shielding gas is not directly blown to the laser processing position, heat loss at the processing position can be suppressed, and the periphery of the processing position can be effectively cooled. It is. Moreover, in which from the outer nozzle 41 is freely relatively vertically movable, so that the cooling range of the shielding gas can be adjusted in correspondence to the machining shape to the inner nozzle 39. [0036]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 Reference of a machining head of a laser beam machine according to the present invention.
It is a sectional view showing a considered example. FIG. 2 is a cross-sectional view showing the flow of assist gas and shield gas. FIG. 3 is a cross-sectional view showing an example of a machining head of a laser beam machine according to the present invention. FIG. 4 is a cross-sectional view showing another embodiment of the machining head of the laser beam machine according to the present invention. FIG. 5 is a front view showing the entire laser beam machine equipped with the machining head of the laser beam machine according to the present invention. 6 is a plan view seen from the direction of arrow VI in FIG. 5. FIG. [Description of Symbols] W Work Material AG Assist Gas LB Laser Beam WA Water (Cooling Medium) 1 Laser Processing Machine 19 Processing Head 39 Inner Nozzle 41 Outer Nozzle 43 Piping SG Shielding Gas 45 Mixer (Mixing Unit)

Claims (1)

(57) [Claims] [Claim 1] A shield in which a cooling medium is mixed around an inner nozzle (39) for ejecting an assist gas to a workpiece (W) and irradiating a laser beam (LB). An outer nozzle (41) for ejecting gas is provided, and the ejection speed of the shield gas from the outer nozzle (41) is configured to be substantially the same as the ejection speed of the assist gas from the inner nozzle (39). Phase against nozzle (39)
The outer nozzle (41) can be adjusted to adjust the height
A machining head of a laser beam machine characterized by being provided so as to be movable in the vertical direction .