JPS5825558B2 - Laser processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a laser processing device suitable for welding processing, and particularly to an improvement of a device in which a processing section is shielded with an inert gas.

For example, in laser welding, exposing the part to be welded to the atmosphere has an adverse effect on the weld, so various techniques have been used to avoid this.

Figure 1 shows one of these innovations, a nozzle for laser processing that can be used for both welding and fusing.

In the figure, a lens holder 2 in which a condensing lens 1 is installed
and the nozzle 3 are coaxially coupled by a spacer 4.

The tip of the nozzle 3 has a double structure of an inner cylinder 5 and an outer cylinder 6 surrounding the lower end 5 of the inner cylinder 5, both of which are tapered.

The tip of the inner cylindrical body 5 serves as an exit hole 8 for the focused laser beam 7, and the tip of the outer cylindrical body 6 serves as an annular blowhole 9 surrounding the injection hole 8.

An inert, for example, argon gas supply pipe 11 is connected to the outer cylinder 6, passing through its side wall and communicating with a header 10 formed between the inner and outer cylinders.

Further, an oxygen gas supply pipe 13 is connected to the upper side of the inner cylindrical body 5 through its side wall.

In the case of this nozzle, a passage 14 that opens in the header 10 and communicates with the inside of the inner cylinder 5 is provided in the side wall of the tapered portion 5' of the inner cylinder 5.

The welding process using the nozzle 3 described above is performed by cutting off the supply of oxygen from the supply pipe 13 and supplying argon gas from the supply pipe 13.

The welded part 17 of the workpiece 15° 16 is shielded with argon gas from the annular blowhole 9 and can be irradiated with the laser beam 7 without being exposed to the atmosphere.
The flow of argon gas ejected from the welding part 17 can prevent the condensing lens 1 from being contaminated by scattered objects such as steam from the welding part 17.

However, the argon gas coming out of the nozzle 9 directly injects the molten pool formed in the welding part 17, and the argon gas enters the inside of the weld and creates pores.
Since the nozzle mentioned above has a structure that does not actively exclude flying objects and steam, there were problems such as the injection hole 8 and jet nozzle 9 at the tip of the nozzle becoming clogged during long periods of use. .

Furthermore, the shield area of the nozzle described above is small, and when welding is performed by moving the laser beam and the workpiece relative to each other, the welded part may be exposed to the atmosphere and oxidized while it is not sufficiently cooled. There was a serious problem.

This invention was made in view of the above-mentioned circumstances, and the shield area is set in a range where the processed part is cooled to a temperature that does not oxidize. By guiding the laser beam and forcibly removing it in a direction perpendicular to the optical path of the laser beam, it is possible to perform laser processing with reliable prevention of oxidation.

Hereinafter, the present invention will be described with reference to drawings showing embodiments.

FIGS. 2 and 3 show an apparatus for laser welding according to an embodiment of the present invention.

In the figure, a laser oscillator 21 is provided, and a laser beam 22 emitted from the laser oscillator 21 passes through a reflecting mirror 23 and a condensing lens 24 to a workpiece 25 a placed on a moving table (not shown). > 25b is focused and irradiated onto the matching portion 26.

Above the workpieces 25 a and 25 b, a rectangular or circular cover plate 27 having an area that sufficiently covers the spot portion of the laser beam irradiation on the mating portion 26 is provided close to the workpieces 25 a and 25 b.
is placed horizontally.

The area of the cover plate 27 varies depending on the processing scanning speed of the movable table, but the important thing is that there is enough room for the temperature of the welded part at the joining part 26 to drop to such an extent that no oxidation reaction with the atmosphere occurs when the cover plate 27 is removed. It should be as wide as .

Further, the cover plate 27 does not necessarily have to be plate-shaped, and can be deformed depending on the shape of the plate.

A hole 28 is bored at approximately the center of the cover plate 27, which is located on the optical path of the focused laser beam 22 that has passed through the focusing lens 24, through which the entire beam of the focused laser beam 22 passes.

Further, above the cover plate 27, a blow pipe 29 connected to a known blower (not shown) is installed with its tip formed in a slit-shaped opening as close as possible to the beam of the focused laser beam 22. has been done.

One end portion of the blower pipe 29 including the above-mentioned tip is fitted into the exhaust pipe 30 .

This exhaust pipe 30 is provided with a ventilation hole 31 through which the entire luminous flux of the focused laser beam 22 passes.
1 is located approximately coaxially with the hole 28.

On the other hand, in addition to drilling holes 28 in the cover plate 27, supply pipes 3 are provided at four locations symmetrically with the exhaust pipe 30 in between.
2 are connected.

These supply pipes 32 are connected to an inert gas supply device and are connected to the workpiece 25a.

An inert gas is supplied to a space 33 between the cover plate 25b and the cover plate 27.

Note that the exhaust pipe 30 is for not expanding the flux caused by the injection from the blast pipe 29 and for guiding the exhaust to a predetermined location, and may be removed if these are not necessary.

Next, the effect of the above configuration will be explained.

First, a blower and an inert gas supply device (not shown) are activated, and a high-speed fluid such as air or nitrogen is flowed from the blow pipe 29 in the direction shown by arrow A, and argon, helium, etc. are supplied from each supply pipe 32. Inert gas is supplied from the directions of arrows C and D, respectively.

The inert gas is ejected toward the surfaces of the workpieces 25a and 25b and flows along the directions of arrows E, F or G, H,
The opposing space 33 is filled.

The filled inert gas is suctioned by the high-speed fluid flowing in the exhaust pipe 30, passes through the hole 28 and the vent hole 31 as shown by arrows I and J, merges with the high-speed fluid, and is discharged in the direction of arrow B.

After achieving this state, the laser oscillator 1 is activated, and in order to relatively scan the laser beam 22 and the workpieces 25 a and 25 b, the movable table (not shown) is scanned and the alignment portion 26 is moved. , Performs welding processing.

The melted scatterings and metal vapor generated from the joint portion 26 that is temporarily melted when irradiated with the focused laser beam 22 are shown by the arrow I.
, J is forcibly exhausted along with the flow of inert gas, and at the same time, the high-speed fluid in the exhaust pipe 30 that generates the flow action shown by arrows I and J is irradiated and melts the gas that creates pores inside the weld. It is forcibly sucked in from inside the mating portion 26 of the part where the gas is attached, and is removed along with high-speed fluid, inert gas, scattered objects, etc. in the direction of arrow B.

The inert gas acting as a shielding gas is also a contributing factor to the above pores, but as mentioned above, the arrow ■.

J, and since it is not sprayed directly onto the joint part 26, it becomes difficult for it to enter into the joint part 26 during melting.

On the other hand, since the cover plate 27 has an area that sufficiently covers the spot portion of the focused laser beam 22 on the mating portion 26, the mating portion 26 that has been irradiated with the focused laser beam 22 is covered with the cover plate 27.
It will not be oxidized even if it comes off and comes into contact with the atmosphere.

As detailed above, in processing such as welding and scribing, the present invention does not directly inject inert gas at or near the processing part to shield it, but rather injects inert gas from the surrounding area away from the processing part. For example, in laser welding processing, inert gas is guided into the laser optical path and a means is provided to discharge it in a direction that intersects the laser optical path, and a cover plate is processed to create a shielding atmosphere. Since the area is configured to be large enough to match the scanning speed, during the welding process, the inert gas generated in the molten zone is forcibly discharged together with the inert gas, making it possible to obtain a welded zone without pores. Furthermore, the conventional problem of oxidation due to exposure to the atmosphere after welding is completed has been resolved by providing a sufficient cover area.

In the above embodiment, gas was flowed at high speed from the blower pipe installed in the exhaust pipe, but liquid such as water may be flowed at high speed.

Also, instead of the exhaust action caused by the high-speed fluid as described above,
Needless to say, it can be replaced by a vacuum suction device, for example.

Furthermore, as shown in FIG. 4, which is a second embodiment of the present invention, the exhaust pipe 30 and the cover plate 27 are not integrated, but are installed separately, for example, so that the exhaust pipe 30 is moved in the vertical direction indicated by the arrow 2-2. By making it possible to move to , the amount of G suction from the hole 28 can be finely adjusted.

FIG. 5 shows a third embodiment of the present invention, in which a cover plate 27 is provided with a groove 34 on the back surface for guiding inert gas toward the hole 28. The flow of inert gas into the exhaust pipe 30 becomes better.

Note that the present invention is not limited to the above-mentioned embodiments, and can be modified in various ways without departing from the spirit of the invention.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a conventional device, Fig. 2 is a cross-sectional view showing an embodiment of the present invention, Fig. 83 is a cross-sectional view taken along the line ■-■ in Fig. 2, and Fig. 4 is a cross-sectional view of the present invention. FIG. 5 is a cross-sectional view showing a second embodiment of the invention, and FIG. 5 is a plan view showing a third embodiment of the invention. 21... Laser oscillator, 22... Laser light, 24... Condensing lens, 25a, 25b
...Workpiece, 27...Covering plate, 28
...hole, 29 ... air pipe, 30 ...
...exhaust pipe, 32...supply pipe.

Claims (1)

[Scope of Claims] 1. A laser oscillator, a condenser lens that condenses laser light emitted from the laser oscillator and irradiates a focused spot on the workpiece, and a combination of the condenser lens and the workpiece. a cover having a hole intersecting the laser beam and passing the laser beam at a position on the optical path of the laser beam; and a cover having a hole in the space facing the cover and the workpiece. and a discharge device positioned above the cover and guiding the inert gas filling the opposing space from the hole to outside the optical path of the laser beam. Laser processing equipment featuring: 2. In the laser processing apparatus according to claim 1, the cover has an area that compensates for the temperature of the processed part after irradiation with the laser beam to decrease to a temperature at which it will not be oxidized when it comes into contact with the atmosphere during processing scanning. A laser processing device characterized by: 3. In the laser processing apparatus according to claim 1, the discharge device has a vent hole, and the vent device is fitted into an outer tube provided in the laser beam path and has one end connected to the vent hole. A laser processing device characterized by comprising an inner tube that is provided as close as possible to the inner tube and ejects a high-speed fluid in a direction intersecting the laser beam passing through the ventilation hole.