JPH07185874A - Machining head of laser beam machine - Google Patents

Abstract

PURPOSE:To improve cutting capability in thickness, cutting speed, and machining stability and also to reduce running cost. CONSTITUTION:In order that a cooling medium MA which is mixed in a sealed gas SG ejected from the jetting port of an outer nozzle 41 is introduced so as to be evenly diffused inside the outer nozzle 41 and that the medium is also atomized again, a throttle SB is provided at least in one place near the jetting port of the outer nozzle. In addition, in order to adjust a blowing position to a work W for the sealed gas SG in which the cooling medium WA is mixed, the relative height of the outer nozzle 41 and an inner nozzle 39 is provided freely variably.

Description

Detailed Description of the Invention

[0001]

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 processing head of a laser processing machine having a nozzle characterized by jetting a cooling medium and assist gas.

[0002]

2. Description of the Related Art As is well known in the prior art, in a laser processing apparatus for processing a plate-shaped work material, a reflector and a laser beam for irradiating the work material with a laser beam from a laser oscillator are provided. The processing head includes a condensing lens that condenses light, and a processing table that horizontally supports and moves the workpiece.

A laser beam in laser processing is oscillated from a laser oscillator and irradiated from a processing head together with an assist gas onto a material to be processed. This assist gas reacts with the material to be processed, assists in melting the material to be processed, and acts to remove the molten metal and slag. It also has the function of protecting the condenser lens from the scattering of the molten metal.

In cutting with a laser beam,
The energy of the laser beam that is intensively applied to the processing point of the work material is absorbed by the work material as thermal energy,
The work material is melted and cut by this thermal energy.

However, when this heat energy is stored in the work material and the temperature of the work material rises, the melting region of the work material tends to widen, and in particular, a laser using high concentration oxygen as an assist gas is observed. In the case of processing, the temperature rise of the material to be processed due to heat accumulation promotes the oxidation reaction of the material to be processed, and the melting region may be expanded unstably, so that accurate cutting may not be performed.

Therefore, in order to perform accurate cutting, it is necessary to forcibly remove the excess heat accumulated in the material to be processed.
As known from Japanese Patent No. 7985, Japanese Patent Application Laid-Open No. 4-135087, Japanese Patent Application Laid-Open No. 4-284995, water spray having a high cooling effect is used.

This water spraying is carried out by ejecting the laser beam and the assist gas coaxially from the inner nozzle of the nozzle and flowing water from the outer nozzle as a double structure. Therefore, the water flowing out from the outer nozzle is caught by the assist gas ejected from the inner nozzle to be in a mist state, and is sprayed on the work material together with the assist gas.

Further, in thick plate processing, the larger the inner nozzle diameter and the longer the straight line portion of the gas blowing portion at the nozzle tip, the better the directionality of the assist gas ejected from the nozzle, and the better the cut surface. It has been known.

[0009]

However, in such a conventional technique, when the assist gas ejected from the inner nozzle is ejected alone, it is immediately ejected because of the relative velocity with the atmosphere. The flow becomes turbulent.
This directional disturbance starts from the outer periphery of the assist gas,
It progresses inward.

Due to this turbulence, the assist gas gradually mixes with the atmosphere to deteriorate the concentration, and similarly, the water entrained in the assist gas is completely mixed into the flow of the assist gas immediately after mixing.

Therefore, since the assist gas in which the water is mixed in the form of mist is blown directly to the working portion and the working progress portion of the work material, the working stability is ensured satisfactorily, but the heat loss is large and the working is possible. Since the plate thickness is reduced and the kerf width is narrowed, in order to obtain the assist gas necessary for removing molten metal and slag, the assist gas pressure is increased to increase the assist gas consumption and reduce the running cost. There was a problem of deterioration.

Further, increasing the nozzle diameter delays the occurrence of turbulence inside the assist gas, and depending on the assist gas pressure and other factors, high-purity assist gas with less turbulence is blown into the groove of the cross section. Although the heat loss due to the direct cooling of the processed part by the cooling water is reduced, there is a problem that the consumption amount of the assist gas is increased and the running cost is deteriorated.

Further, lengthening the straight portion of the tip of the inner nozzle has the effect of preventing the disturbance of the flow of the assist gas, but there is a problem that the laser beam is likely to interfere and the focus and the movable range are shortened. .

Furthermore, when the material to be processed is mild steel, etc.,
There was a problem of rust generation due to cooling water and a problem of cost increase due to rust prevention measures on the processing machine side.

An object of the present invention is to improve a cutting head, a cutting speed, and a processing stability in order to improve the above-mentioned problems, and to provide a processing head of a laser processing machine for reducing a lining cost. To provide.

[0016]

In order to achieve the above object, the present invention ejects an assist gas onto a material to be processed and a shield gas mixed with a cooling medium around an inner nozzle for irradiating a laser beam. An outer nozzle is provided, and mixing means for mixing the cooling medium and the shield gas is provided in the pipe connected to the outer nozzle, and the outer nozzle is at a speed substantially the same as the ejection speed of the assist gas ejected from the inner nozzle. Introduced as a processing head of a laser processing machine that ejects a shielding gas mixed with a mist-like cooling medium, so that the cooling medium mixed with the shielding gas ejected from the ejection port of the outer nozzle is equalized inside the outer nozzle. At the same time, in order to re-atomize, at least one narrowed portion was provided in the vicinity of the ejection port of the outer nozzle to configure the processing head of the laser processing machine.

In order to adjust the spraying position of the work material of the shield gas mixed with the cooling medium, the relative heights of the outer nozzle and the inner nozzle are variably provided.
Further, it is desirable that the ejection port of the outer nozzle is a ring-shaped or a plurality of small holes provided in the circumference.

[0018]

By employing the processing head of the laser processing machine according to the present invention, the assisting gas is ejected from the inner nozzle together with the laser beam to cut the material to be processed, so that the material to be processed is melted and melted. Metals and slag can be removed.

An outer nozzle is provided on the outer circumference of the inner nozzle, means for mixing the shield gas and the cooling medium from the outer nozzle is provided, and the mixed shield gas and cooling medium are equalized in the outer nozzle. Introduce. Furthermore, since a throttle part that atomizes the cooling medium when ejecting the shield gas from the outer nozzle is provided, and it is ejected from a position higher than the assist gas ejection position of the inner nozzle, the shield gas with a well-designed flow of assist gas Is shielded from the surroundings, and the atomized cooling medium cools the vicinity of the processed portion of the work material.

At this time, since the shield gas mixed with the mist-like cooling medium is ejected at substantially the same speed as the ejection speed of the assist gas, the assist gas is ejected as compared with the case where the assist gas is in direct contact with the atmosphere as in the conventional case. The speed difference becomes very small. For this reason, the flow of the assist gas is jetted to the processing position of the material to be processed without disturbing the directivity. Along with this, the mist-like cooling medium is not caught in the assist gas and is not directly sprayed to the processing position of the workpiece,
There is no heat loss at the processing position and processing efficiency is improved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings.

7 and 8 show the entire laser processing machine 1. The laser beam machine 1 includes a base 3, a post 5 fixed to one end of the base 3 and vertically formed, and an overhead beam 7 supported above the base 3 in a horizontal cantilever shape by the post 5. An NC control device 9 for numerically controlling the laser processing machine 1 is provided on the front surface (lower side in FIG. 8) of the post 5.

On the upper end of the base 3, a plurality of free bear balls 11 for horizontally mounting a work W to be processed is placed.
Is provided with a fixed table 13. 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 is the laser oscillator 2 provided on the left side of the laser processing machine 1 in the figure.
The laser beam LB from the laser beam No. 3 is provided so as to be refracted in the direction of the condenser lens 17 and the workpiece W, and further mirror assemblies 25, 25 for sending from the laser oscillator 23 to the mirror assembly 15 are provided. .

Therefore, such a laser processing machine 1 receives the laser beam LB from the laser oscillator 23 and irradiates the laser beam LB for processing the workpiece W through the processing head 19.

On the other hand, in order to supply and position the workpiece W, a horizontally movable carriage base 27, and a pair of works movably provided on the carriage base 27 and holding the workpiece W. A carriage 31 having a clamp 29 is provided.

The carriage base 27 is a fixed table 13.
Of the movable table 33 provided on both sides of the fixed table 13, and is slidably mounted on a pair of guide rails 35 provided on both sides of the fixed table 13 in parallel with each other. 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 positioned in the X-axis direction.

Therefore, the positioning of the workpiece W in the processing region located directly below the processing head 19 is performed by 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,
In addition, the carriage base 27 is controlled to move in the Y direction along the guide rail 35.

Next, the processing head 19 will be described with reference to FIG.

The processing head 19 is provided with a condenser lens 17 for condensing the laser beam LB on the upper side of the central portion thereof, and oxygen or the like near the upper end portion of the side wall of the internal space G having a downwardly pointed conical shape. An assist gas ejection port 37 for ejecting the assist gas AG is provided. The inner nozzle 39 that irradiates the workpiece W with the laser beam LB and ejects the assist gas AG onto the workpiece W at the center of the lower end of the processing head 19 directly below the condenser lens 17.
Is provided.

On the outer periphery of the inner nozzle 39, an outer nozzle 41 for ejecting a shield 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.

However, from the pipe 43 to the outer nozzle space 41
The mixed gas of the shield gas SG and the water WA introduced at the upper end of A is tangentially introduced from the pipe 43 to the outer nozzle space 41A as shown in FIG.
B is formed. Therefore, the mixed gas is rotated and equalized inside the outer nozzle space 41A.

The lower end of the outer nozzle space 41A has the nozzle 2
The outer nozzle 41 is formed as a circular groove on the lower end surface of the first nozzle. The pipe 43 connected to the outer nozzle 41 is provided with a mixer 45 for mixing the atomized water WA into the sent shield gas SG.

In the processing head 19 configured as described above, the laser beam LB sent from the laser oscillator 23 through the mirror assembly 15 is used as the condenser lens 17.
Are collected and irradiated from the inner nozzle 39 to the cut portion of the workpiece W, and the assist gas AG is jetted 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 a flow rate substantially the same as the flow rate of the assist gas AG.

When the shield gas SG is jetted from the outer nozzle 41 as described above, the assist gas AG jetted from the inner nozzle 39 has a relative velocity with the shield gas SG, not with the atmosphere, and as a result. The relative speed decreases. For this reason, the flow of the assist gas AG is not disturbed by the shielding effect of the shield gas SG, and a large amount of gas with good directionality is blown into the processed portion, so that the piercing time is shortened and the cut surface roughness is improved to improve the kerf width. Can be narrowed and the processing speed can be increased.

The shield gas SG has a mixer 45.
Thus, the mist-like water WA is mixed in advance, so that the cooling effect of the heat generated in the workpiece W by the cutting process can be enhanced. Here, since the flow velocity of the shield gas SG substantially matches the flow velocity of the assist gas AG, the shield gas S
Since the atomized water WA mixed in G enters the assist gas AG at a slow speed and is not directly sprayed onto the processing portion, the laser beam LB is not lost by the water WA and the processing speed can be reduced. Absent.

Further, since the shield gas SG and the assist gas AG are less mixed after jetting from the nozzle, inexpensive air or the like can be used as the shield gas SG. Since the shield gas SG and the assist gas AG are provided separately from each other, the flow rate or gas pressure of each gas can be set separately. For example, if the shield gas SG is increased, it is possible to prevent the condensing lens from being contaminated due to spatter that is generated during the piercing process.

As shown in FIG. 3, the outer nozzle 41 is movably provided in the vertical direction so that the relative height with respect to the inner nozzle 39 can be adjusted, and the height of the outer nozzle 41 is N.
If it is controlled by the C device, the shield gas SG
It is also possible to change the cooling range by the machining shape.

Further, in the above-described embodiment, as shown in FIG. 1 or 3, by providing at least one throttling portion SB in the vicinity of the jet port at the lower end of the outer nozzle 41, water droplets inside the outer nozzle space 41A. The atomized fog can be atomized again. Further, in the above-described embodiment, the outer nozzle 41 is provided on the outer circumference of the inner nozzle 39.
As shown in FIG. 3, the ejection ports of the outer nozzle 41 may not be ring-shaped but may be small holes 47 arranged at equal intervals.

Furthermore, it is also possible to directly spray only the shield gas SG, directly eject water WA or oil instead of the shield gas SG, or use oil, gas or a mixed gas thereof cooled by an external cooling device. it can.

As shown in FIG. 5, the shielding gas S
When water WA is used as the cooling medium mixed in G, it is desirable to supply it from a water tank 49 in which a water-soluble rust preventive agent or rust preventive oil BO has been mixed in advance.

A system diagram of a water spray pipe which is an embodiment employing the water tank 49 will be briefly described.

Referring to FIG. 6, reference numeral 51 is an internal pressure tank, the water pipe is shown by a one-dot chain line, and the air pipe is shown by a dotted line. A solenoid 53 is provided on the outlet side of the internal pressure tank 51 for opening and closing the water pipe, and a solenoid 55 is provided on the outlet side of the internal pressure tank 51 for opening and closing the air pipe. Further, a check valve 57 is provided in the middle of the inlet water pipe to the internal pressure tank 51.

The reserve tank, which is the water tank 49, contains water mixed with water WA and rust preventive oil BO, reference numeral 59 is a pump, reference numeral 61 is a solenoid, reference numeral 63 is a filter regulator, Reference numeral 65 is a regulator.

The control method of the water spray pipe as described above is as follows.
The solenoid 61 is controlled by opening and closing in response to a signal from the main tank to turn the motor on and off, and replenish the internal pressure tank 51 with rustproof water. Also, the solenoids 53, 5
In the control of No. 5, the water spray is O when the assist gas AG is ON.
If the command of N is issued, the solenoids 53 and 55 are simultaneously opened and the water spray nozzle alone does not operate. This is because if the water spray is made while the assist gas AG is stopped, the condenser lens 17 will be soiled if there is a shield such as a material at the tip of the nozzle.

Further, the water WA is stopped by the solenoid 53,
After shifting the timing by 0.5 seconds or more, the solenoid 5
Stop the air and assist gas AG by 5. This is because, if the assist gas AG stops before the water spray nozzle, the water contaminates the condenser lens 17 when the nozzle is near the material. Further, by closing the water of the solenoid 53 before the atomizing air of the solenoid 55, the water in the outer nozzle 41 is blown out, so that water does not leak from the nozzle after processing and water does not collect at the tip of the inner nozzle 39. When water accumulates at the tip of the inner nozzle 39, the laser light LB is blurred. In addition, when the processing head 19 is removed, the water collected at the tip is sucked into the inside and stains the condenser lens 17.

With the above-described structure, the outer nozzle space 41A is used to eject the shield gas SG mixed with the cooling medium into the outer nozzle space 41A of the outer nozzle 41.
The shield gas SG is introduced so as to rotate inside the outer nozzle 41 by communicating with the connection path 41B formed in the tangential direction of the. Further, by providing the narrowed portion SB at the tip of the outer nozzle 41, the cooling medium mixed with the shield gas SG can be re-atomized at the time of ejection, and the ejection port of the outer nozzle 41 can be the ejection port of the inner nozzle 39. It was set at a higher position further away.

Therefore, since the shield gas SG ejected from the outer nozzle 41 is blown onto the workpiece W along the outer shape of the inner nozzle 39, the shield gas SG having a uniform flow around the assist gas AG during machining. And the mist-like cooling medium cools the vicinity of the processed portion of the workpiece W. Therefore, heat loss does not occur at the processing position, and the processing efficiency can be improved.

The present invention is not limited to the above-described embodiments, but can be implemented in other modes by making appropriate changes.

[0050]

As will be understood from the above description of the embodiments, according to the present invention, since the structure is as described in the claims, the outer nozzle is provided on the outer periphery of the inner nozzle, A means for mixing the shield gas and the cooling medium was provided in the pipe connected to the outer nozzle, and this was introduced into the outer nozzle so as to be even. In addition, a throttle portion that atomizes the cooling medium when ejecting the shield gas from the outer nozzle is provided, and it is ejected from a position higher than the assist gas ejection position of the inner nozzle, so that a shield gas with a well-equipped flow assists during machining. The gas is shielded from the surroundings, and the atomized cooling medium cools the vicinity of the processed part.

Therefore, heat loss at the processing position does not occur, the cuttable plate thickness, the cutting speed, and the processing stability can be improved, and the running cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a processing head of a laser processing machine according to the present invention.

FIG. 2 is an enlarged explanatory diagram along line II-II in FIG.

FIG. 3 is a sectional view showing another embodiment of the processing head of the laser processing machine according to the present invention.

FIG. 4 is an explanatory bottom view showing still another embodiment of the processing head of the laser processing machine according to the present invention.

FIG. 5 is an explanatory diagram of a pipe path that connects the water tank and the processing nozzle according to the present invention.

FIG. 6 is a piping system explanatory diagram of the water spray piping system according to the present invention.

FIG. 7 is a front view showing the entire laser processing machine equipped with the processing head of the laser processing machine according to the present invention.

8 is a plan view seen from the direction of arrow VIII in FIG.

[Explanation of symbols]

 1 Laser Processing Machine 19 Processing Head 39 Inner Nozzle 41 Outer Nozzle 43 Piping 45 Mixer (Mixing Means) W Work Material AG Assist Gas LB Laser Beam WA Water (Cooling Medium) SG Shield Gas SB Throttling Part

Claims (4)

[Claims] 1. An outer nozzle for ejecting a shield gas mixed with a cooling medium is provided around an inner nozzle for ejecting an assist gas onto a material to be processed and for irradiating a laser beam,
Mixing means for mixing the cooling medium and the shield gas is provided in the pipe connected to the outer nozzle, and the outer nozzle generates a mist-like cooling medium at a speed substantially the same as the ejection speed of the assist gas ejected from the inner nozzle. Use as a processing head of a laser processing machine that ejects the mixed shield gas, and introduce the cooling medium mixed with the shield gas ejected from the ejection port of the outer nozzle so that it is equalized inside the outer nozzle and re-atomize. In order to do so, at least one narrowed portion is provided in the vicinity of the ejection port of the outer nozzle, the processing head of a laser processing machine. 2. The relative height between the outer nozzle and the inner nozzle is variably provided in order to adjust the position at which the shield gas mixed with the cooling medium is sprayed on the workpiece. The processing head of the laser processing machine according to 1. 3. The machining head of a laser beam machine according to claim 1, wherein the ejection port of the outer nozzle has a ring shape. 4. The machining head of a laser beam machine according to claim 1, wherein the ejection port of the outer nozzle is a plurality of small holes provided on the circumference.