JPH06218572A - Machining head of laser beam machine - Google Patents

Abstract

PURPOSE:To provide a machining head of a laser beam machine capable of improving cuttability, cutting surface roughness and cutting stability and reducing running cost. CONSTITUTION:A mixing device(mixing means) 45, which mixes a shield gas SG and misty state water(cooling medium)WA, is arranged in a piping 43 communicating to an outside nozzle 41, which is arranged around an inside nozzle 39, at machining, the shield gas shields around an assist gas AG, further, a misty state water cools the neighborhood of machining part of a work W. At this time, because the shield gas SG mixed with a misty state water WA is jetted approximately at the same speed as the jet speed of assist gas AG, the flow of assist gas is not disturbed and is jetted on the machining position of the work W with keeping good orientation. Accordingly, a misty water is not jetted on the machining position of the work W, not generating heat loss at the machining position and improving machining efficiency.

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 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.

Therefore, in order to perform accurate cutting, it is necessary to narrow the heat-affected portion. Therefore, in such thermal processing cutting, cooling is performed as a cooling means for the material to be processed, especially when cutting thick plates. A highly effective water spray is used.

This water spraying is carried out by ejecting the laser beam and the assist gas coaxially from the inner nozzle of the double-structured nozzle and letting water flow from the outer nozzle. 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.

[0008]

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,
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, assist gas with less turbulence is blown into the groove in the cross section. There is a problem that the consumption of the assist gas increases and the running cost deteriorates.

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, and therefore enters the cutting groove when the flow of the assist gas is disturbed. The amount of gas and the flow velocity may decrease, and molten metal may adhere to the back surface or streaks may be disturbed. Then, the water flowing out from the outer nozzle is entrained by the assist gas and becomes a mist state and is sprayed onto the processed portion of the work material, so that the processing stability is ensured satisfactorily, but the heat loss is large and the processing speed increases. This causes a reduction in the workable plate thickness.

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

The object of the present invention was made by paying attention to such a conventional technique, and it is possible to improve the cutting ability, the cut surface roughness and the processing stability and to reduce the running cost. It is to provide a processing head of a processing machine.

[0012]

In order to achieve the above-mentioned object, a processing head of a laser processing machine according to the present invention has a structure in which an assist gas is jetted to a material to be processed and an inner nozzle for irradiating a laser beam is provided around the inner nozzle. An outer nozzle for ejecting a shield gas mixed with a cooling medium is provided.

A 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 atomized at a speed substantially the same as the ejection speed of the assist gas ejected from the inner nozzle. It is desirable that a shield gas mixed with a cooling medium be ejected.

[0014]

According to the processing head of the laser processing machine of the present invention, since the assisting gas is ejected from the inner nozzle together with the laser beam to cut the material to be processed, the material to be melted and the molten metal are assisted. And slugs can be removed.

Since the outer nozzle is provided around the inner nozzle, and the pipe connected to the outer nozzle is provided with a mixing means for mixing the shield gas and the atomized cooling medium, the shield gas surrounds the assist gas during processing. And the mist-like cooling medium cools the vicinity of the processed part of the work material.

At this time, since the shield gas mixed with the mist-like cooling medium is ejected at a speed substantially the same as the ejection speed of the assist gas, the assist gas is ejected as compared with the conventional case where the assist gas is in direct contact with the atmosphere. 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.

[0017]

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

FIG. 5 and FIG. 6 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. 6) 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 a 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 beam 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 work material W, a horizontally movable carriage base 27, and a pair of works movably provided on the carriage base 27 and holding the work material W. A carriage 31 having a clamp 29 is provided.

The carriage base 27 is the 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. 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 work piece W in the work area located directly below the work head 19 is performed by the carriage 3 equipped with the work clamp 29 for clamping the work piece 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.

An outer nozzle 41 for ejecting a shield gas SG such as air and water WA as a cooling medium is provided on the outer periphery of the inner nozzle 39. 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 41A forms a circular groove on the lower end surface of the nozzle 21 to form the outer nozzle 41.
Then, 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.

Referring to FIG. 2, when the shield 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 has a relative velocity with the shield gas SG,
As a result, the relative speed becomes small. Therefore, 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. The 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
The mist-like water WA mixed in G enters the assist gas AG at a low speed and is not directly sprayed to the processing portion, so that the laser beam LB does not cause a loss due to the water WA and the processing speed can be reduced. Absent.

Furthermore, 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 provided movably 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. That is, as shown on the right side of the drawing, the outer nozzle 41
Is relatively increased with respect to the inner nozzle 39, the shielding gas SG spreads over a wide range, so that the cooling range expands. The left side of the drawing shows a case where the lower end of the outer nozzle 41 is at the same height position as the lower end of the inner nozzle 39.

Further, in the above embodiment, the outer nozzle 41 is provided on the outer circumference of the inner nozzle 39, but as shown in FIG. 4, the ejection ports of the outer nozzle are not ring-shaped but are arranged at regular intervals. It may be 47.

Further, instead of the shield gas SG, water W is used.
It is also possible to directly eject A or oil, or use oil, gas, or a mixed gas thereof cooled by an external cooling device.

[0035]

The processing head of the laser beam machine according to the present invention is constructed as described above, and the outer nozzle is provided around the inner nozzle, and the pipe connected to this outer nozzle is sprayed with the shield gas and atomized. Since the mixing means for mixing the cooling medium is provided, the shield gas shields the assist gas from the surroundings at the time of processing, and the atomized cooling medium can cool the vicinity of the processed portion of the workpiece. Therefore, since the assist gas is blown to the processed portion in a good direction, the cutting ability, the cut surface roughness and the processing stability are improved, and the waste of the assist gas is reduced, and the running cost can be reduced.

At this time, the shield gas mixed with the mist-like cooling medium is ejected at a speed substantially the same as the ejection speed of the assist gas. Therefore, the assist gas is ejected as compared with the conventional case where the assist gas is in direct contact with the atmosphere. 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.

[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 a cross-sectional view showing flows of an assist gas and a shield gas.

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

FIG. 5 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.

FIG. 6 is a plan view seen from the direction of arrow VI in FIG.

[Explanation of symbols]

 W Workpiece 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 Shield gas 45 Mixer (mixing means)

Claims (3)

[Claims] 1. A laser beam machine according to claim 1, further comprising: an outer nozzle for ejecting a seal gas mixed with a cooling medium around an inner nozzle for ejecting an assist gas onto a material to be processed and for irradiating a laser beam. Processing head. 2. The processing head of a laser beam machine according to claim 1, wherein mixing means for mixing the cooling medium and the seal gas is provided in a pipe connected to the outer nozzle. 3. The outer nozzle ejects a shield gas mixed with a mist-like cooling medium at a speed substantially the same as the ejection speed of the assist gas ejected from the inner nozzle. Processing head of laser processing machine.