JPS5861991A - Method and device for laser welding - Google Patents

Abstract

PURPOSE:To increase penetration and to obtain uniform results of welding by providing a suction nozzle which permits fine adjustment in the weld zone near the focus of the lens of a laser welding machine and sucking gaseous plasma through said nozzle. CONSTITUTION:The laser light 2 oscillated from a laser oscillator is converged onto the focus on base materials by a lens. The gaseous plasma 1 generated in this time is sucked through >=1 piece of suction nozzles 6 which are provided near the weld zone and are finely adjustable forward and backward, by means of a suction pump 7. Thus the gas 1 generated in the weld zone is removed without interfering the passing part for the laser light 2, whereby penetration is increased and the uniform results of welding are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION In laser welding, when welding thick plates, it is necessary to increase the laser output, but increasing the output does not mean that the penetration increases in proportion.

The reason for this is that as the output increases, the plasma gas L generated at the crater 3 becomes larger as an island, as shown in FIG. 1, and obstructs the transmission of the laser beam 2. For this purpose, as shown in Fig. 2, a method is usually provided in which a nozzle 5 is provided, from which argon, helium, or a mixture thereof is ejected as an assist gas to blow away the plasma gas 1 and increase penetration. Adopted.

The angle e formed between the nozzle 5 that ejects this assist gas and the base material 4 is such that even if the angle e is 01ζ, the plasma gas rising from the base material can be removed, so it is possible to deepen the injection, but it is more effective. In order to remove this plasma gas, it is better to set a large angle θ. However, if this angle θ is set too large, the assist gas hits the folds of the crater 3 and is reflected, causing turbulence, which is a disadvantage of the plasma gas 1. In addition, if the flow weight of the assist gas 1 for removing the plasma gas 1 is small, it will not be effective, but if it is too large, the molten metal will be blown away, resulting in cutting.

It is considered difficult to appropriately select the angle θ and flow rate of the assist gas nozzle, successfully remove the plasma gas 1, and obtain uniform welding results.

The present invention solves these problems and relates to a method and apparatus for obtaining a uniform deep depth even when welding thick plates. That is, as shown in FIG. 8, a suction nozzle 6 is provided near the crater 3, and a suction pump 7 is connected to this. Since the purpose of this suction posi 7 is to suction the plasma gas 1, even a vacuum cleaner or the like can sufficiently achieve the purpose.

Plasma gas 1 when inhaling compared to when blowing out
is removed without causing turbulence or reflection on the walls of the crater 3, and the penetration becomes deep and uniform.

The number of suction nozzles 6 may be IIm, but a plurality of suction nozzles 6 may also be provided. In the case of 2＠, it may be possible to move the nozzle forward or backward or to the left and right with respect to the direction of welding progress.By increasing the number of nozzles, when sucking the plasma gas 1, it is possible to prevent this gas from passing through the laser beam. It will no longer move.

However, the structure becomes complicated and it becomes difficult to see inside the welded part, so it is better to decide the number appropriately depending on the required penetration depth. The amount of suction required is several times that of the amount of wrinkles when blown away. The position of the suction nozzle 6 must be appropriate with respect to the crater 3. Therefore, if there is a mechanism that can finely adjust the welding area in the vertical and longitudinal directions, the welding area should be heated with argon gas, helium gas, hypooxygen gas, or a mixture of these to prevent oxidation and nitridation during actual welding. It is necessary to shield with a gas. FIG. 4 shows an explanatory diagram of one implementation of this. If a cap 9 is provided to allow the shielding gas 8 to flow, it is necessary to flow the shielding gas 11 for the laser.

In addition, in order to create a red appearance in the welded area or to prevent the occurrence of blowholes when welding #XwIA rimmed steel, it is necessary to add wire containing a deoxidizing agent. Chimento can be used differently.

The effectiveness of such a nozzle has been described in detail with respect to the case where it is applied to welding, but since the purpose of the suction nozzle is to remove plasma gas, it goes without saying that it is also effective when used for cutting.

A laser welder is an expensive device, and the price increases rapidly as the output increases. However, it is not possible to weld thick plates in proportion to the output of a laser welder. The cause of this was the difficulty in removing the plasma gas, but the present invention has made it possible to increase penetration using a simple suction device. It can be said that the effects are extremely high and the benefits are extremely large.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a normal laser welding method, Figure 2 is a schematic diagram of a laser welding method with an assist gas nozzle added to blow away the plasma gas generated at the weld, and Figure 8 is a diagram of a plasma gas suction bomb ffl. FIG. 4 is a schematic diagram of a laser welding method in which a pulling nozzle is added, and FIG. 4 is an explanatory diagram of one implementation of FIG. 8. 1: Plasma gas, 2: Laser beam, 6: Suction nozzle,
7: Suction pump

Claims (1)

[Claims] 1. In laser welding, one or a number of nozzles are provided near the welding area in order to remove the plasma gas generated at the welding area without blocking the passage of the laser beam, A method of connecting to a suction pump and sucking plasma scum from this nozzle. 2. A laser welding machine equipped with a laser oscillator and a lens that converges the oscillated laser has one or multiple nozzles, a mechanism that can finely adjust the nozzles up and down, back and forth, and a suction gib near the focal point of the lens. A laser welding device characterized by: