JPH034460Y2 - - Google Patents

Description

[Detailed explanation of the invention] (Industrial field of application) This invention relates to deep penetration welding using a laser beam, and is particularly effective for plasma removal gas, which uses a large amount of inert gas. Regarding the welding equipment to be used.

(Prior Art) Conventionally, this type of laser welding equipment requires shielding gas for the purpose of preventing oxidation of the welded part, similar to other welding such as CO ₂ arc welding.

That is, Fig. 2 shows part of a conventional welding device, where a is a welding head (torch), b is a condensing lens,
c is nozzle, d is assist gas or shield gas such as helium (He) or argon (Ar) f
, g is the shield atmosphere, and h is the workpiece (sample for welding).

(Problems to be solved by the invention) In the conventional welding equipment described above, welding defects may occur because the shielding gas atmosphere at the laser welding part is not shielded in any way, which poses problems in welding quality. Unless an expensive inert gas such as argon or argon is used, a sufficient penetration depth cannot be obtained as shown in FIG.

Another problem with laser welding is that plasma is generated by the reaction between metal vapor from the keyhole and inert gas during laser welding, and this plasma absorbs the laser beam, resulting in energy not being used effectively for welding. arise.

Therefore, in order to remove this plasma, a method is often used in which the same gas as the shielding gas is sprayed at high pressure, as shown in FIG. i indicates a plasma removal nozzle. Further, the laser welding apparatus described in Japanese Patent Application Laid-Open No. 53-40661 also destroys plasma by using the same gas as the shielding gas, similar to the one shown in FIG.

However, this method requires a large amount of expensive inert gas, resulting in a significant increase in running costs, and has the disadvantage of being impractical.

(Means and effects for solving the problem) This invention was made in view of the above points, and it surrounds the welding nozzle at the tip of the welding head to completely seal the welding part and create a shielding gas atmosphere. ,
A shielding nozzle is provided to perform laser welding by replenishing inert gas, an inert gas outlet and a gas inlet are provided on the peripheral wall of the nozzle, and a pipe communicating these outlet and inlet is provided with a shielding nozzle. A suction pump, a tank discharge pump, and a plasma removal nozzle are installed in sequence, and by completely shielding the shield welding part, a good product with no welding defects can be obtained, and the use of large amounts of expensive inert gas can be avoided. By recirculating and using the necessary plasma removal gas within the pipe, running costs can be reduced, and the penetration depth can be improved by removing plasma.

(Example) An example of this invention will be described below based on the drawings.

In Figure 1, 1 is a welding head (torch), 2
3 is a condensing lens, 3 is a welding nozzle, 4 is a shielding nozzle surrounding the nozzle 3, and 5 is a laser beam. Reference numeral 8 denotes a welding sample, in which a shielding nozzle 4 completely seals the laser welded part to form a shielding gas atmosphere 9. Reference numeral 17 denotes an air barrier material such as Teflon. A gas cylinder 18 is filled with an inert gas such as helium or argon, and these shielding gases are appropriately supplied from the replenishment part 7 through a pipe.

A gas outlet 10 is provided on the peripheral wall of the shielding nozzle 4 and communicates with a pipe 12 as shown.

Similarly, a gas inlet 11 is provided on the peripheral wall of the shielding nozzle 4, and a plasma removal nozzle 13 communicating with a pipe 12 passes through the inlet 11 toward the shielding gas atmosphere 9 from the outside. A suction pump 1 is provided in the middle of the pipe 12 that communicates the gas outflow section 10 and the gas inflow section 11.
4, a tank 16, and a discharge pump 15 are provided so that plasma removal gas, which uses a large amount of expensive inert gas, can be circulated and used.

By circulating the inert gas in a nearly hermetically sealed manner in this way, good welding quality can be obtained, and running costs can be significantly reduced. Therefore, it is only necessary to replenish from the small amount replenishing section 7 only the degraded inert gas and the leaked inert gas into the atmosphere.

Moreover, since plasma can be removed, the penetration depth can be expected to be improved, and laser welding can also be applied to welding thick plates.

(Effect of the invention) This invention is made as described above, and the laser welding part is completely sealed by the shielding nozzle that surrounds the welding nozzle to form a shielding gas atmosphere, so welding defects can be avoided. Good quality welded products are obtained.

Furthermore, by cycling the plasma removal gas, which uses a large amount of helium and argon, which are expensive inert gases, the inert gas can be circulated in a nearly sealed manner, resulting in significantly improved running times. Cost can be reduced.
In other words, you can use as much expensive inert gas as you want, and you only need to replenish a small amount of the deterioration of the inert gas and the amount that leaks into the atmosphere, making it extremely economical and effective use of inert gas. becomes.

Furthermore, since the plasma can be removed in this way, it is expected that the penetration depth will be improved, so that laser welding can be applied to welding thick plates.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the laser welding device of this invention, Fig. 2 is a schematic diagram of a part of the conventional device, and Fig. 3 shows the penetration depth when using each shielding gas. A graph showing the relationship between penetration depth when each shielding gas is used. Figure 4 shows an example of a device using a conventional method in which the same gas as the shielding gas is sprayed to remove plasma. show. 1... Welding head, 3... Laser nozzle, 4
... Shield nozzle, 9 ... Gas atmosphere, 10
...Gas outflow section, 11...Gas inflow section, 12...
Tank, 13... Plasma removal nozzle, 14...
Suction pump, 15...discharge pump, 16...tank.

Claims (1)

[Scope of utility model registration request] The welding nozzle 3 at the tip of the welding head 1 is surrounded and the welding area is completely sealed to create a shielding gas atmosphere 9.
A shielding nozzle 4 is provided so as to perform laser welding by replenishing inert gas 6, 7, and an inert gas outlet 10 and a gas inlet 11 are provided on the peripheral wall of the nozzle 4. Outflow section 10 and inflow section 1
1, a suction pump 14, a tank 16, a discharge pump 15, and a plasma removal nozzle 13 are sequentially provided in a pipe 12 communicating with the laser welding apparatus.