JP3291097B2 - Processing head of laser processing machine - Google Patents

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 ejecting a cooling medium and an assist gas.

[0002]

2. Description of the Related Art As is well known, in a laser processing apparatus for processing a plate-shaped workpiece, a reflecting mirror for irradiating a laser beam from a laser oscillator to the workpiece and a laser beam are used. A processing head having a condenser lens for condensing light, and a processing table for horizontally supporting and moving the workpiece are provided.

[0003] A laser beam in laser processing is oscillated from a laser oscillator and is irradiated from a processing head to a workpiece together with an assist gas. The assist gas reacts with the workpiece to assist the melting of the workpiece, and acts to remove the molten metal and slug. It also has the function of protecting the condenser lens from scattering of molten metal.

In the cutting process using a laser beam,
The energy of the laser beam intensively applied to the processing point of the workpiece is absorbed by the workpiece as thermal energy,
The work material is melted and cut by the heat 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 be widened. In particular, a laser using high-concentration oxygen as the assist gas is used. In the case of processing, a rise in the temperature of the workpiece due to heat storage promotes the oxidation reaction of the workpiece, and the molten region is unstably widened, so that accurate cutting may not be performed.

Accordingly, in order to perform accurate cutting, it is necessary to forcibly remove excess heat stored in the work material.
As is known from JP-A-7985, JP-A-4-135087, JP-A-4-284995, etc., water spray having a high cooling effect is used.

[0007] This water spraying is performed by ejecting a laser beam and an assist gas coaxially from the inner nozzle of the nozzle as a double structure and flowing water from the outer nozzle. Therefore, the water flowing out of the outer nozzle is entrained by the assist gas ejected from the inner nozzle into a mist state, and is sprayed on the workpiece together with the assist gas.

In the processing of a thick plate, the direction of the assist gas ejected from the nozzle becomes better as the inner nozzle diameter is larger and the length of the linear portion of the gas outlet at the tip of the nozzle is longer, so that the cut surface is in a good state. It has been known.

[0009]

However, in such a conventional technique, when the assist gas ejected from the inner nozzle is ejected by itself, the assist gas is ejected immediately after ejection due to the relative speed with the atmosphere. The direction becomes disturbed.
This directional disturbance starts from the outer periphery of the assist gas,
Proceed inward.

[0010] The turbulence causes the assist gas to gradually mix with the atmosphere to deteriorate the concentration, and similarly, immediately after the water entrapped in the assist gas mixes, the assist gas completely mixes with the flow of the assist gas.

Therefore, since the assist gas in which the water is mixed in the form of mist is directly blown to the processing portion and the processing progress portion of the workpiece, the processing stability is sufficiently secured, but the heat loss is large, and the processing is possible. In addition to reducing the thickness of the plate and reducing the width of the kerf, in order to obtain the assist gas necessary for removing molten metal and slug, increase the pressure of the assist gas, increase the consumption of the assist gas, and reduce the running cost. There was a problem of deterioration.

Also, increasing the nozzle diameter delays the generation 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 cross-sectional groove. Although the heat loss due to the direct cooling of the processing portion by the cooling water is reduced, there is a problem that the consumption of the assist gas increases and the running cost is deteriorated.

Further, increasing the length of the straight portion at the tip of the inner nozzle has the effect of preventing disturbance of the flow of the assist gas. However, there is a problem that the laser beam easily interferes and the focal point and the movable range are shortened. .

Further, when the work material is a mild steel material or the like,
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 provide a processing head of a laser processing machine which aims to improve the cuttable plate thickness, the cutting speed, and the processing stability and reduce the lining cost in order to improve the above problems. To provide.

[0016]

Means for Solving the Problems Conventional problems as described above
In view of the above, the invention according to claim 1 focuses a laser beam.
To the workpiece at the position below the condenser lens
An inner nozzle that blows out assist gas is provided.
A mixed gas of a shielding gas and a cooling medium is
Machining a laser machine with an outer nozzle for jetting
Assist ejected from the inner nozzle at the head
Gas flow rate and mixed gas ejected from the outer nozzle
And the tip of the outer nozzle
On the inner surface, project inward to atomize the gas mixture
This is a configuration in which an aperture portion is provided.

The invention according to claim 2 is the invention according to claim 1.
In the processing head of the laser processing machine, the outer nozzle
The tip of the inner nozzle projects from the tip.
You.

[0018]

[0019]

[0020]

[0021]

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

FIGS. 7 and 8 show the entire laser beam machine 1. The 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 in a horizontal cantilever shape above the base 3 by the post 5. An NC controller 9 for numerically controlling the laser beam machine 1 is provided on the front surface of the post 5 (the lower side in FIG. 8).

A plurality of free bear balls 11 are placed on the upper end of the base 3 in order to place the workpiece W to be processed horizontally.
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 a tip (lower end) of the processing head 19.

The mirror assembly 15 is provided with a laser oscillator 2 provided on the left side of the laser beam machine 1 in the drawing.
3 is provided so as to refract the laser beam LB from 3 toward the condensing lens 17 and the workpiece W, and further provided are mirror assemblies 25, 25 for sending from the laser oscillator 23 to the mirror assembly 15. .

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 workpiece W, a horizontally movable carriage base 27 and a pair of workpieces movably provided on the carriage base 27 and gripping the workpiece W are provided. A carriage 31 having a clamp 29 is provided.

The carriage base 27 is a 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, and a Y-axis is provided by a driving device (not shown). 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 positioning of the workpiece W in the processing area located immediately 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 on the carriage base 27 in the X direction,
In addition, the movement is performed by controlling the movement of the carriage base 27 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 condensing lens 17 for condensing the laser beam LB on the upper side of the center, and oxygen or the like is formed near the upper end of the side wall of the internal space G having a conical shape that is pointed downward. An assist gas ejection port 37 for ejecting the assist gas AG is provided. At the center of the lower end of the processing head 19 immediately below the condenser lens 17, an inner nozzle 39 for irradiating the workpiece W with the laser beam LB and ejecting the assist gas AG to the workpiece W is provided.
Is provided.

On the outer periphery of the inner nozzle 39, an outer nozzle 41 for jetting 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 that is continuous along the shape of the inner space G, and is connected to a pipe 43 at the upper end of the outer nozzle space 41A.

However, from the pipe 43, the outer nozzle space 41
A mixed gas of the shielding gas SG and the water WA introduced into the upper end of the pipe A is tangentially introduced from the pipe 43 to the space between the outer nozzle spaces 41A as shown in FIG.
B is formed. Therefore, the mixed gas rotates and equalizes inside the outer nozzle space 41A.

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

In the processing head 19 configured as described above, the laser beam LB sent from the laser oscillator 23 via the mirror assembly 15 is
The workpiece W is cut by the assist gas AG being ejected toward the workpiece W while being radiated from the inner nozzle 39 to the cut portion of the workpiece W. At this time, the shield gas SG in which the atomized water WA is mixed by the mixer 45 is jetted from the outer nozzle 41 at a flow rate substantially equal to the flow rate of the assist gas AG.

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 has a relative velocity with respect to the shield gas SG, not the atmosphere. The relative speed decreases. 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, so that the piercing time is shortened, the cut surface roughness is improved, and the kerf width is increased. Can be reduced, and the processing speed can be further increased.

Further, a mixer 45 is added to the shielding gas SG.
As a result, since the water WA in the form of mist is mixed in advance, the cooling effect of the heat generated in the workpiece W by the cutting process 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
Since the speed of entry of the atomized water WA mixed into the G into the assist gas AG is slow, and the water WA is not sprayed directly on the processing portion, 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 the mixing of the shielding gas SG and the assist gas AG after the nozzle is jetted is small, inexpensive air or the like can be used as the shielding gas SG. Since the shield gas SG is provided separately from the assist gas AG, the flow rate or gas pressure of each can be set separately. For example, if the shielding gas SG is strengthened, it is possible to prevent contamination of the condenser lens due to spatter generated during piercing.

[0038] Incidentally, as shown in FIG. 3, or outside the nozzle 41
The inner nozzle 39 projects from the outer nozzle 4
1 is higher than the inner nozzle 39 ,
Gas SG effectively seals around the assist gas AG.
And the mist cooling medium is processed
That can effectively suppress direct spraying on the part
It is.

Further, in the above-described embodiment, as shown in detail in FIG. 3, near the ejection port at the lower end of the outer nozzle 41, a throttle portion SB slightly protruding inward is provided.
is there. Therefore, the mist that has turned into water droplets inside the outer nozzle space 41A can also be atomized again. Further, in the above embodiment, the outer nozzle 41 is provided on the outer periphery of the inner nozzle 39. However, as shown in FIG.
May be small holes 47 arranged at equal intervals instead of a ring shape.

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

Further, as shown in FIG.
When water WA is used as the cooling medium mixed in G, it is preferable to supply the water WA from a water tank 49 in which a water-soluble rust preventive or rust preventive oil BO is mixed in advance.

A schematic diagram of a water spray pipe according to an embodiment employing the water tank 49 will be schematically described.

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

The reserve tank, which is the water tank 49, contains water in which water WA and rust-preventive oil BO are mixed, reference numeral 59 denotes a pump, reference numeral 61 denotes a solenoid, reference numeral 63 denotes a filter regulator, and reference numeral 63 denotes 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 to open and close by a signal from the main tank, thereby turning the motor ON and OFF, and replenishing the internal pressure tank 51 with rust preventive water. In addition, solenoids 53 and 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 never operates. This is because, if the water spray is emitted while the assist gas AG is stopped, the condensing lens 17 is stained when 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 for 0.5 seconds or more, solenoid 5
5 Turn off the air and assist gas AG. This is because if the assist gas AG stops before the water spray nozzle, water contaminates the condenser lens 17 when the nozzle is near the material. In addition, since the water in the solenoid 53 is closed before the air for spraying the solenoid 55, the water in the outer nozzle 41 is blown out. Therefore, water does not leak from the nozzle after processing, and water does not accumulate at the tip of the inner nozzle 39. When water accumulates at the tip of the inner nozzle 39, the laser beam LB is blurred. In addition, when the processing head 19 is removed, the water collected at the tip is sucked into the inside and soils the condenser lens 17.

According to the configuration described above, the shield gas SG mixed with the cooling medium is jetted 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 due to the communication through the connection path 41B formed in the tangential direction. Further, by providing the throttle 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 changed to the ejection port of the inner nozzle 39. A higher position farther away.

For this reason, the shield gas SG ejected from the outer nozzle 41 is sprayed on the workpiece W along the outer shape of the inner nozzle 39, so that the shield gas SG having a well-flowed flow around the assist gas AG at the time of machining. And the mist-like cooling medium cools the vicinity of the processed portion of the workpiece W. Thus, it is possible to improve processing efficiency without generating heat loss at the processing position.

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

[0050]

As is clear from the above description,
In the invention according to claim 1 of the present invention, the inner nozzle 3
Flow rate of assist gas AG ejected from nozzle 9 and outer nozzle
Make the flow velocity of the mixed gas ejected from 41 almost equal,
In addition, the mixed gas is applied to the inner peripheral surface of the tip of the outer nozzle 41.
An inwardly protruding throttle portion SB is provided to make a mist
Between the assist gas AG and the mixed gas
The relative velocity of the gas is small, and the assist gas A
Effective shielding without disturbing the flow of G
And the cooling medium in the mixed gas is assist gas A
What can be mixed with G and sprayed directly on the processed part
Not something. Therefore, accurate laser cutting
As well as effective cooling around the laser processing part.
It can be done effectively.

In the invention according to claim 2,
Project the tip of the inner nozzle from the tip of the outer nozzle 41
Configuration, the cooling medium in the mixed gas assists
Invasion into the gas AG and flow of the assist gas AG
That can more effectively prevent disturbing
It is.

[Brief description of the drawings]

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

FIG. 2 is an enlarged explanatory view taken 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 piping path that connects a water tank and a processing nozzle according to the present invention.

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

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

FIG. 8 is a plan view seen from the direction of arrow VIII in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser processing machine 19 Processing head 39 Inner nozzle 41 Outer nozzle 43 Pipe 45 Mixer (mixing means) W Workpiece material AG Assist gas LB Laser beam WA Water (cooling medium) SG Shield gas SB Draw-down part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23K 26/14 B23K 26/06

Claims (2)

(57) [Claims] 1. A method for converging a laser beam (LB).
The workpiece (W) is positioned below the condenser lens (17).
Nozzle (3) that blows out assist gas (AG)
9), and a seal is provided on the outer periphery of the inner nozzle (39).
Gas mixture of gas (SG) and cooling medium (WA)
Laser processing machine with an outer nozzle (41)
In the processing head, ejected from the inner nozzle (39)
Assist Gas (AG) Flow Rate and Outer Nozzle
Set the flow velocity of the mixed gas ejected from (41) to be almost equal.
Mixed with the inner peripheral surface of the tip of the outer nozzle (41).
A throttle part that protrudes inward to make the gas into a mist
Processing of a laser beam machine characterized by providing (SB)
head. 2. The laser processing machine according to claim 1,
The front end of the outer nozzle (41)
The inner nozzle (39) must have a protruding tip.
And a processing head for a laser processing machine.