JPH0530871Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a laser processing device for welding metal materials and the like using laser light, and particularly relates to a protective structure for a condensing lens that condenses laser light.

[Conventional technology]

When performing metal processing such as welding using a laser processing device, there is a problem in that flying objects such as spatter generated during the processing adhere to the condensing lens, shortening the life of the condensing laser. As a countermeasure to this problem, a method was devised as shown in Japanese Patent Application Laid-Open No. 59-223191, in which a nozzle for protecting the lens was installed at the tip of the device, and a high-speed gas flow crossed the optical axis of the condensing lens and flowed out in a film form. has been done.

[The problem that the idea attempts to solve]

When a high-speed airflow is formed on the bottom surface of the condenser lens, as in the above-mentioned device, the high-speed airflow prevents spatter from entering the device, and has a great effect on adhesion to the condenser lens. However, a problem arises in that the shielding gas is disturbed during welding by the high-speed airflow. This occurs because the high-speed airflow formed on the lower surface of the condenser lens entrains the surrounding air, creating an airflow near the welding area and disrupting the flow of the shielding gas that is supplied at low speed. It is something. Therefore, a problem arises in that the gas shielding of the welded part becomes incomplete and defects such as blowholes occur in the welded part.

The present invention focuses on the above-mentioned problems, and aims to prevent spatter and the like from adhering to the condenser lens, ensure gas shielding of the weld, and eliminate defects in the weld.

[Means to solve the problem]

A laser processing device according to the present invention that meets this purpose irradiates a workpiece with a laser beam focused by a condensing lens provided in a laser processing head, and shields the laser beam irradiation point of the workpiece. In a laser processing apparatus that performs laser welding by supplying gas, a jet port for jetting dry air toward the workpiece is provided below the condenser lens in the laser processing head, and the A plate-shaped member extending substantially perpendicular to the optical axis of the laser beam is disposed below the laser processing head, and the plate-shaped member has a diameter slightly smaller than the cross-sectional diameter of the laser beam through which the laser beam passes. An orifice with a large diameter is formed, and a first nozzle is provided on the lower surface side of the plate-shaped member to be arranged concentrically with the laser beam that has passed through the orifice and to eject shielding gas toward the laser beam irradiation point on the workpiece. A second air current is arranged near the orifice on the upper surface of the plate-like member to form a high-speed airflow that crosses the laser beam.
A nozzle is provided, a drive means is connected to the plate-shaped member for vertically moving and rotating the plate-shaped member, and the plate-shaped member is placed between the lower surface of the laser processing head and the upper surface of the plate-shaped member. It consists of a piece with an escape space for raising it.

[Effect]

In the laser processing device configured in this way, below the condenser lens in the laser processing head,
Since a jet is provided to blow out dry air toward the workpiece, the pressure inside the laser processing head becomes higher than atmospheric pressure, preventing foreign matter such as welding fumes (dust) from entering the laser processing head. It becomes difficult.

In addition, since the second nozzle forms a high-speed airflow that crosses the laser beam, this high-speed airflow also prevents welding fumes, spatter, etc. from entering the processing head and reaching the surface of the condenser lens. Adhesion of spatter etc. is reliably prevented. Furthermore, since the diameter of the orifice is only slightly larger than the cross-sectional diameter of the laser beam, the effect of preventing the intrusion of spatter and the like is great.

Since the first nozzle is arranged concentrically with respect to the laser beam that has passed through the orifice, the shielding gas can be ejected from the entire circumference toward the laser beam irradiation, significantly improving the shielding properties of the welded part. becomes possible.

Here, during welding work, dry air is ejected from the jet nozzle in the laser processing head toward the workpiece, but between the bottom surface of the laser processing head and the top surface of the plate-shaped member where the first nozzle is provided. is provided with an escape space for allowing the plate-shaped member to escape upwards, so most of the dry air flowing out from the laser processing head can be diffused outward, and the dry air is also directed to the second nozzle. Since the flow is blocked by the high velocity airflow, dry air from the laser processing head is prevented from entering the first nozzle. Therefore, dry air is not mixed into the shielding gas, and deterioration in welding quality is prevented.

Since the plate member can be moved up and down and rotated by the driving means, even if the workpiece has a protrusion or step that projects upward, the first nozzle can escape upward, and the first nozzle can be moved upwardly. It becomes possible to prevent interference between the nozzle and the workpiece. Once the first nozzle has been released from the workpiece, the first nozzle can be positioned at a predetermined position again by lowering the plate member using the driving means. Therefore, it is possible to weld the first nozzle always in close proximity to the welded member, and a good shielding effect can be maintained.

〔Example〕

Preferred embodiments of the laser processing apparatus according to the present invention will be described below with reference to the drawings.

The figure shows the vicinity of a processing head of a laser processing apparatus according to an embodiment of the present invention. In the figure, 1 indicates the main body of the laser processing head. The processing head 1 is formed into a substantially cylindrical shape, and a lens holder 2 is attached to the inside of the processing head main body 1. A condensing lens 3 that condenses the laser beam L is located inside the lens holder 2. The condensing lens 3 is fixed to the lens holder 2 by being tightened by a ring screw 6 which is screwed into the lens holder 2 via an O-ring 4 and a retaining ring 5.
An annular flow path 7 for circulating cooling water is formed in the processing head main body 1, and this flow path 7 is connected to a cooling pipe 8 attached to the outer peripheral surface of the processing head main body 1.
is connected to. The cooling pipe 8 is connected to a cooling water supply source (not shown), and the condenser lens 3 is indirectly cooled by the cooling water supplied from the cooling water supply source.

A subchamber 9 extending in the circumferential direction is formed between the processing head main body 1 and the lens holder 2. The auxiliary chamber 9 is located on the outer periphery of the processed lens 3, and the gap connected to the auxiliary chamber 9 is sealed with an O-ring or the like (not shown). The auxiliary chamber 9 communicates with a passage 12 formed in the machining head body 1, and this passage 12 is connected to a pipe 13 attached to the outer peripheral surface of the machining head body 1. pipe 13
is connected to, for example, a compressor (not shown) that pumps dry air. The subchamber 9 communicates with a plurality of jet ports 14 formed in the lens holder 2 . Each jet port 14 is arranged radially around the optical axis A of the laser beam L, and is arranged in a subchamber 9.
The dry air _P1 sent to the lower workpiece 40
It is starting to erupt towards.

A sleeve 16 is attached to the lower end of the processing head body 1 with a spacer 15 interposed therebetween. Further, a nozzle 18 is attached to the lower end of the sleeve 16. The sleeve 16 and the nozzle 18 are integrated by a screw structure, and a main chamber 19 through which the laser beam L passes is formed inside them. The inner circumferential surface of the nozzle 18 is formed into a tapered surface 18a whose cross-sectional area decreases as it goes downward. Further, the lower end surface of the nozzle 18 is formed into a tapered surface 18b that becomes smaller in diameter as it goes downward.

Below the laser processing head, i.e. nozzle 18
A plate member 20 extending substantially perpendicular to the optical axis A of the laser beam L is disposed below the laser beam L. One end of the plate member 20 is connected to a jig device 2 for moving the workpiece.
It is attached to a drive means 22 fixed to the frame of 1. The driving means 22 is for rotating and moving up and down, and the drive means 22 moves the plate member 20 as necessary.
can be moved up and down and rotated. An escape space S for raising the plate member 20 is provided between the lower surface of the laser processing head 1 and the upper surface of the plate member 20.

The plate member 20 is formed with an orifice 23 through which the laser beam L passes and whose diameter is slightly larger than the cross-sectional diameter of the laser beam L. Orifice 23 is
It is a tapered hole, and the opening diameter on the upper surface side of the plate-shaped member 20 is smaller than the opening diameter on the lower surface side. That is, the opening diameter on the upper surface side of the orifice 23 is formed to be as large as the cross-sectional diameter of the laser beam L.
A nozzle 24 located on the same axis as the orifice 23 is provided on the upper surface of the plate member 20 . The nozzle 24 is formed in the shape of a donut disk, and its inner diameter is larger than the orifice 23, and its upper surface is formed into a tapered surface 24a whose diameter increases as it goes downward. That is, the tapered surface 24a on the upper surface side of the nozzle 24 is symmetrical with respect to the tapered surface 18b of the nozzle 18 on the laser processing head side.

A first nozzle 25 is provided directly below the orifice 23 on the lower surface of the plate member 20 to supply shielding gas to the laser beam irradiation point B (welding area).
The axis of the first nozzle 25 coincides with the axis of the orifice 23 (optical axis A of the laser beam L). That is, the first nozzle 25 is arranged concentrically with the laser beam L. The inside of the first nozzle 25 is formed such that the cross-sectional area of the flow path decreases as it goes downward. A workpiece 40 to be laser welded is located directly below the ejection port 26 of the first nozzle 25 . That is, the laser beam L focused by the condensing lens 3 passes through the orifice 23 and the first nozzle 25 and reaches the ejection port 2 of the first nozzle 25.
It converges to one point just below 6.

An air supply pipe 27 is provided on the side of the first nozzle 25.
is attached so that the shielding gas G supplied to the air supply pipe 27 is ejected from the ejection port 26 toward the laser beam irradiation point B. Also,
A plurality of vent holes 28 are provided at the upper part of the air supply pipe 27 on the side surface of the first nozzle 25 .

A second nozzle 30 is provided near the orifice 23 on the upper surface of the plate member 20 to form a high-speed airflow P ₂ that crosses the laser beam L. The second nozzle 30 is arranged along the upper surface of the plate-like member 20 and extends from the drive means 22 side toward the donut-shaped nozzle 24 . The second nozzle 30 tapers toward the orifice 23, and a high-speed airflow _P2 is ejected from the ejection port 31 at the tip toward the optical axis A of the laser beam L. This second nozzle 30 is
It is fixed to the plate member 20 via the block 33,
At the rear end of the nozzle is a hose 3 that pumps dry air.
3 is connected.

Next, the operation of the above laser processing apparatus will be explained.

When welding the workpiece 40 by irradiating the laser beam L, first, the workpiece 40 is attached to the jig device 21.
It is clamped by a clamping means (not shown). That is, during laser welding, the workpiece 40 is moved by the jig device 21 along the welding line, and the laser processing head is kept stationary at a fixed position.
When the workpiece 40 is clamped by the jig device 21, the drive means 22 is activated, and the plate-shaped member 20 swings and descends toward the laser processing head 1 side. That is, the plate member 20 is rotated from the rest position toward the laser processing head 1, and the center of the orifice 23 and the optical axis A of the laser beam L passing through the main chamber 19 of the laser processing head 1 are aligned.

When the plate member 20 moves to the fixed position, dry air P ₁ is supplied to the pipe 13, and this dry air P ₁
is ejected downward from the condenser lens 3 from the plurality of ejection ports 14 via the auxiliary chamber 9 . At the same time,
High-pressure dry air is force-fed to the second nozzle 30 through the hose 33, and the high-pressure dry air is jetted toward the center of the orifice 23 from the jet port 31 at the tip of the second nozzle 30.

High-speed airflow created by the second nozzle 30
P ₂ crosses the laser beam L, continues straight in the horizontal direction, and scatters in the distance. In this case, the lower end surface of the nozzle 18 on the processing head side and the upper surface of the nozzle 24 on the upper surface side of the plate-shaped member 20 are both tapered surfaces, so that the convergence effect of the high-speed airflow that crosses the laser beam L is enhanced. , the straightness of the high-speed airflow P ₂ ejected from the second nozzle 30 is improved. Therefore,
Nozzle 1 for spatter etc. generated by laser welding
This high-speed airflow P ₂ reliably prevents the intrusion from the laser beam 8 , and prevents spatter and the like from adhering to the condensing laser 3 .

Further, since the diameter of the orifice 23 is formed to be only slightly larger than the cross-sectional diameter of the laser beam L, the effect of this intrusion of spatter etc. into the processing head is also improved.

At the same time as the high-speed airflow P ₂ is ejected from the second nozzle 30, shielding gas such as Ar gas is sent to the air supply pipe 27, and the workpiece 27 is ejected from the ejection port 26 at the tip of the first nozzle 25. A shielding gas G is ejected toward the welding part (laser beam irradiation point B) to perform gas shielding during welding. In this case, the high-speed airflow P ₂ from the second nozzle 30 creates a negative pressure in the surroundings, and the shielding gas G flows through the high-speed airflow.
Dry air is supplied from above the main chamber 19 as a purge gas, although there is a risk of it getting caught up in _P2.
Since P ₁ is ejected from the tip of the nozzle 18, the pressure in the vicinity of the tip of the nozzle 18 is balanced, and negative pressure around the high-speed airflow P ₂ is prevented. Therefore, the shielding gas is hardly disturbed by the high-speed airflow _P2 from the second nozzle 30, and gas shielding during welding is reliably performed.

If it is necessary to blow out dry air at a higher speed from the second nozzle 30, the amount of shielding gas from the air supply pipe 27 is increased, and this shielding gas G and the atmosphere flowing in from the vent 28 are It is also possible to prevent the generation of negative pressure above.

In this embodiment, the plate member 20 is moved up and down and rotated by the driving means 22, so that even if the surface shape of the workpiece 40 is complex and uneven, for example, The first nozzle 25 can be temporarily released by moving the plate member 20.

Furthermore, by making the plate-shaped member 20 rotatable, the plate-shaped member 20 can be released from directly under the laser processing head 1 to the outside, making cleaning and inspection of the orifice 23 and the first nozzle 25 much easier. It becomes easier.

[Effect of idea]

According to the laser processing apparatus of the present invention, the following effects can be obtained.

(1) Below the condensing lens in the laser processing head,
A jet nozzle is provided for blowing out dry air toward the workpiece, and a second nozzle for forming a high-speed airflow that crosses the laser beam is provided on a plate-shaped member provided below the processing head. It is possible to reliably prevent weld fumes, spatter, and the like generated by welding from entering the laser processing head, and to prevent foreign matter from adhering to the surface of the condenser lens.

Further, since the diameter of the orifice of the plate-shaped member through which the laser beam passes is made slightly larger than the cross-sectional diameter of the laser beam, the effect of preventing the intrusion of spatter and the like can be further improved.

(2) Since the first nozzle is arranged concentrically with respect to the laser beam that has passed through the orifice, it is possible to eject the shielding gas from the entire circumference toward the laser beam irradiation point of the workpiece, and welding The shielding properties of the parts can be significantly improved.

As a result, the laser welded portion is reliably shielded by the shielding gas, and welding defects such as blowholes can be prevented from occurring.

(3) The plate-shaped member provided with the second nozzle acts as a shielding means to prevent the high-speed airflow from flowing toward the first nozzle that supplies the shielding gas, so the shielding gas is not disturbed by the high-speed airflow. Almost nothing happens.

In addition, an escape space is provided between the lower surface of the laser processing head and the upper surface of the plate member where the first nozzle is provided, so that the plate member can escape upward. Most of the drying air can be diffused outward, and since the flow of the drying air is blocked by the high-speed airflow from the second nozzle,
Ingress of dry air from the laser processing head into the nozzle is prevented. Therefore, dry air is not mixed into the shielding gas, and deterioration in welding quality can be prevented.

(4) Since the driving means is connected to the plate-like member, the plate-like member can be moved up and down. This allows the first nozzle to be raised and lowered even if there are protrusions or steps that protrude upward on the surface of the workpiece, and after the first nozzle is temporarily released upward, the first nozzle It becomes possible to position the nozzle at a predetermined position.

Therefore, even if the surface shape of the workpiece is complex, welding can be performed with the first nozzle that ejects the shielding gas always close to the workpiece, and a good shielding effect can be maintained. I can do it.

(5) Since the plate-like member can be rotated by the drive means, the first nozzle, which tends to attract spatter, can be cleaned while being moved outward from directly under the laser processing head. The cleaning efficiency of the first nozzle can be significantly improved.

[Brief explanation of drawings]

The figure is a sectional view of a main part of the laser processing apparatus of the present invention. 1... Laser processing head (processing head body),
3... Condensing lens, 20... Plate member, 22...
Drive means, 23... Orifice, 25... First nozzle, 30... Second nozzle, 40... Workpiece, A... Optical axis of laser beam, B... Laser beam irradiation point, L... ...Laser light, P ₁ ...Dry air, P ₂ ...
High-speed airflow, G...shielding gas, S...escape space.

Claims (1)

[Scope of utility model registration request] In a laser processing device that performs laser welding by irradiating a workpiece with a laser beam focused by a condensing lens provided in a laser processing head and supplying a shielding gas to the laser beam irradiation point of the workpiece. , an ejection port for ejecting dry air toward the workpiece is provided below the condensing lens in the laser processing head; A plate-shaped member extending in a right angle direction is disposed, an orifice through which the laser beam passes and whose diameter is slightly larger than the cross-sectional diameter of the laser beam is formed in the plate-shaped member, and an orifice is formed on the lower surface side of the plate-shaped member. , disposing a first nozzle that is arranged concentrically with the laser beam passing through the orifice and spouting a shielding gas toward the laser beam irradiation point of the workpiece;
A second nozzle for forming a high-speed airflow that crosses the laser beam is provided near the orifice on the upper surface of the plate-like member, and a driving means for vertically and rotationally moving the plate-like member is connected to the plate-like member, A laser processing apparatus characterized in that an escape space for raising the plate-shaped member is provided between the lower surface of the laser processing head and the upper surface of the plate-shaped member.