JPH0259038B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a welding method and a welding apparatus for plate materials, which are designed to improve quality.

[Prior Art] Conventionally, apparatuses for butt welding plates using a laser beam have used a single beam as shown in FIG. 1 to perform linear seam welding by applying a single beam to a joint. That is, in FIG. 1, a laser beam 6 is condensed by a lens 3, the converged beam is applied to a joint 8, and a welding nozzle 2 or a material to be welded 1,
1' is welded while being moved in a direction perpendicular to the plane of the drawing. At this time, in order to remove plasma generated in the joint 8, assist gas such as argon gas is supplied to the nozzle 2 through the supply port 7, and welding is performed while being injected from the tip of the nozzle 2.

Furthermore, if there is a gap in the joint 8 of the plates 1, 1', the convergent beam is normally applied to a position that is biased toward either the welded material 1 or 1', as shown in FIG. That is, in FIG. 2, the convergent beam arrival point is set toward the material to be welded 1 away from the gap center line.

If the gap is small, it is possible to weld with sufficient quality.

However, when the gap becomes large compared to the plate thickness, it becomes impossible to weld using the method shown in Figure 2. Therefore, conventionally, in order to widen the applicable gap range even a little, a method has been adopted in which the focus position of the beam is shifted to increase the diameter of the convergent beam. Increasing the convergent beam diameter in this way not only widens the weld bead width and increases the amount of energy input, but also increases the heat-affected area of the plate and increases the amount of distortion, making it difficult to improve welding quality. There was a drawback.

[Summary of the invention]

This invention was made to eliminate the above-mentioned drawbacks. A pair of laser beams having different optical axes are set so that the focal points at the abutting portions of the plates are at a predetermined interval, and the laser beams are emitted at predetermined intervals. Provided are a method and a welding device for welding plate materials in which irradiation is performed alternately.

[Embodiments of the invention]

FIG. 3 shows an embodiment of the invention. In the figure,
1 and 1' are plate materials arranged at a predetermined interval, 2 is a processing nozzle for welding, and 3 and 3' are condenser lenses, each of which is fixed to the nozzle 2 via a predetermined support member. is focused on one of the plates 1 and 1'. Reflecting mirrors 4 and 4' are placed facing each other at a predetermined angle, and 5 is a reflecting mirror placed between the reflecting mirrors 4 and 4', which converges the light received from the reflecting mirrors 4 and 4', respectively. lens 3,
3' is reflected. 6 is a gas supply port connected to the nozzle 2, and the above 2 to 6 constitute a processing head 7 capable of irradiating a laser beam. 8 is a part to be joined, and 9 and 9' are reflecting mirrors 4 and 9, respectively.
4', e.g. a pulsed laser beam having outputs in alternately opposite directions. 10 and 10' are the convergent beam arrival points,
They are kept at a predetermined interval.

In such FIG. 3, when pulsed laser beams 9 and 9' are applied alternately at predetermined time intervals,
The laser beams 9, 9' passing through the condensing lenses 3, 3' are converged through the reflecting mirrors 4, 4' and 5, and become convergent beams that strike the plates 1, 1' at their respective destination points 10, 10'. melt. Therefore, the plate materials 1,
1' and supplying assist gas from the gas supply port 6, the parts 8 to be joined are alternately welded.

Note that the pulses 9 and 9', which have different optical axes, are
It may be supplied from two laser oscillators, or it may be dividedly supplied from one laser oscillator. Furthermore, irradiation may be performed alternately for each single pulse and for each multiple pulse.

〔Effect of the invention〕

As explained above, according to the present invention, laser beams having different optical axes are set such that their focal points at the abutting portions of the plates are spaced at a predetermined interval, and the laser beams are irradiated alternately at predetermined intervals. As a result, even if the distance between the joints becomes slightly larger,
The quality of welded parts can be ensured.

[Brief explanation of drawings]

FIGS. 1 and 2 are block diagrams showing a conventional system, respectively, and FIG. 3 is a block diagram showing an embodiment of the present invention. In the figure, 1 and 1' are plate materials, 3 is a condenser lens, 4 and 4' are reflecting mirrors, 5 is a reflecting mirror, 7 is a processing head, 9 and 9' are lasers, and 10 and 10' are focal points. Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Claims] 1. In a method of butting plate materials and welding the abutted portions with a laser beam, a pair of laser beams having different optical axes are set so that their focal points at the abutting portions are spaced apart by a predetermined distance, A method for welding plate materials characterized by irradiating laser beams alternately at predetermined time intervals. 2. In a plate welding device that abuts a first plate material and a second plate material at a predetermined interval and welds the abutted portions with a laser beam, the first plate material and the second plate material of the abutted portion are respectively focused. A first laser beam incident on a first optical axis different from the optical axis of the first focusing lens is reflected by a first focusing lens and a second focusing lens arranged so that the angles of the first focusing lens and the second focusing lens match. a pair of first reflecting mirrors arranged so as to be incident on the first condensing lens; and a second light beam that is different from the first optical axis and the optical axis of the second condensing lens. A plate welding device comprising a pair of second reflecting mirrors arranged so that a second laser beam incident at the axis is reflected and incident on the second condensing lens.