DE2147373A1 - Method of welding with the aid of a continuous, focused laser light beam - Google Patents

Description

BF / ü / C C 2 4 1 Λ

F 5687 ■ ^ 'V

SER

COEPAGNIE GENEHALE D ¹ ELEGTRICITe 54, Rue La Boetie, PARIS (8), France

PROCESS FOR WELDING USING A CONTINUOUS, FOCUSED LASER LIGHT BUNCH

The invention relates to a method for welding with With the help of a laser light beam, in particular a welding process with the help of a continuous, focused beam of laser light.

For welding two parts together on a specific one As is well known, the two parts concerned are grounded at the Place where the welding is to be made, brought into contact with each other, and then this becomes the point of contact surrounding material melted. The molten substance of the two parts mixes and solidifies during the Cool down, which bonds the two parts together.

For performing certain difficult welding jobs the energy of a laser light beam is currently used. A laser can be used for spot and continuous welding

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Welds are carried out. Become a spot weld Solid-state laser used in pulse mode, the laser pulses be less than or about ten milliseconds. Laser pulses are perfect for welding metal parts suitable.

For example, watch springs are welded to their holder

For continuous welding, for example of plastic parts, continuous lasers, in particular COp-I> aser used. To carry out a continuous The weld seam can either be the focussing point of the light beam a continuous laser on the line of contact the two parts can be moved along, or the contact line of the two parts can be moved and the laser light beam remain fixed.

Since at present the continuous laser, in particular the gas lasers such as COp lasers, and considerable powers They can emit energies with a higher efficiency than all other lasers in pulse mode used for spot welds. For this purpose, the continuous laser light beam is simply chopped up with the aid a chopper that periodically covers the laser light beam. For example, one of the most famous choppers is called a controllable aperture designed as it is used in cameras. There are other choppers, especially electro-optic ones Chopper, however difficult to use. the

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However, the use of choppers only has disadvantages, because they are very easily "damaged because the laser beam is constantly falling on their input surface, and on the other hand require they use precision mechanics with a complicated electronic control device.

The invention aims to eliminate these drawbacks.

The aim of the invention is also to carry out a spot welding process by means of a continuous laser light beam without covering the latter, with which a weld can be achieved, the one with a pulsed laser performed welding is equivalent.

Another aim of the invention is to use a method for welding with the help of a continuous, focused laser light beam without covering the latter, with which a clean, high quality weld point can be achieved with a laser in pulse mode.

The invention relates to a method for welding with the aid of a continuous, focused laser light beam, characterized in that it consists in the welding point in the focused laser light beam, outside of the focussing point, in order to carry out preheating, and the welding point for this in the focused laser light beam and then to coincide with the focus point to create a local melting to achieve, while the welding point continues in the laser

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keep the bundle of light, and then move it out of the focus point lead out in order to anneal the welding point cause.

The description with reference to the drawing contains other features and advantages of the method according to the invention, which illustrates its individual phases in more detail.

This figure relates to the welding of two parts 1 and 2, for example two metal parts, which are so side by side are arranged so that they are welded together at least at one point 3 can be.

The laser light bundle 4 used for welding comes from a continuous laser not shown in the figure, for example a gas laser such as a COp laser. The laser light beam 4 can also emerge from a continuously operating solid-state or liquid laser; by the way give all continuously working lasers dissipate enough energy to weld between at least two materials to be able to undertake the same or different types.

The light bundles emitted by the lasers are cylindrical and can therefore be viewed from a schematic in the Fig. With 10 designated converging lens in point 5 are focused.

The welding of the two parts 1 and 2 at the point takes place as follows; the two parts 1 and 2, which are in the Point 3 are in contact with each other, are shown in their starting position (A). Then the two parts

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at (B) in the beam 4, outside of the focus point 5, introduced in such a way that it preheats on and around point 3 to learn at the moment when the temperature of the material at the welding point 3 with the melting temperature of the material coincides, creating a significant temperature gradient on one short distance as well as damage to the parts as a result of the thermal stress. The position (B) of the parts 1 and 2 and the time required for preheating will depend on the parameters such as texture the material used and the energy density of the laser light beam certainly.

Parts 1 and 2 can either remain in position (B) for a certain time or, as soon as point 3 is roughly aligned with the axis of laser light beam 4, slowly moved in the direction of focal point 5 at a speed that ensures that the preheating temperature is reached just before point 3 reaches focussing point 5.

As soon as this preheating temperature is reached, the Parts 1 and 2 in the focus point 5 of the laser light blind 4 to achieve a local melt on and around the point. This position of parts 1 and 2 is in the Pig labeled (C). As is well known, a focused laser beam nienteils exactly in one point, but in a first approximation accordingly a rotating cylinder is focused, the diameter of which has otwa the wavelength of the laser beam

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and its length for certain converging lenses about a few Can be millimeters. The parts can either be in the Cylinders of light are held for a certain period of time is generally about ten milliseconds and corresponds to the duration of the light pulses from pulsed solid-state lasers, which be used for spot welding, or they can be used in the light cylinder at a certain speed be moved in such a way that the point 3 moves in this sufficiently long to ensure a 'local melting. As soon as the melting is achieved in point 3, parts 1 and 2 continue in the direction of propagation of the Laser light bundle moved, held out of focus and for example to point (D) to achieve annealing of the weld and a good quality weld. Like position (B), position (D) is preferably determined by experiments. Once the welding is done is, the two welded together parts are led out of the laser light beam 4 and, for example, into the Position (E) brought.

In the figure, the arrows 6, 7> 8 and 9 denote the individual movements of parts 1 and 2, whereby the parts can first move into the converging part or into the diverging part Part of the light beam brought and then, after they have been brought into focus, in the converging or diverging part of the light beam are brought.

In certain cases the lens can be moved the three phases of the process, i.e. preheating, melting

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and annealing to achieve; on the other hand you can use lenses variable focal length can be used.

In those cases where the parts fall into one of the two Parts of the light beam, i.e. the diverging or converging toilet, brought and then, according to their penetration through the focal point are brought into the other part, the welding process according to the invention can take place automatically. Namely, according to the method, when the annealing is performed at (D), for example, another Pair of parts brought into position (B) and preheated there, with the parts already inserted in their position (D) remain.

If the parts are not led out of the laser light beam, but a new pair of parts into the Bundle is brought, it is preferable to bring these parts into the converging part of the bundle first and use them then to lead into the diverging part of the bundle according to the direction of propagation of the bundle. The ones in the The converging part of the light beam covers the part and the two annealed parts can be removed v / ground while the next two parts are being preheated. That way, the annealed parts can go faster cool because they are not exposed by the laser light beam.

It should be noted that between the points where the preheating and annealing takes place, point 3

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of parts 1 and 2 are preferably essentially corresponding the axis of symmetry of the laser light "bundle 4" moves.

In the example described of the application of the invention The laser light beam is through a method Rotation converging lens 10 focused, but it can also Cylindrical converging lenses are used to "make wider welds." in the order of magnitude of a few millimeters.

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Claims (3)

2H7373 PATENT CLAIMS V 1 »J Method for welding with the aid of a continuous, focused laser light beam, characterized in that it consists in bringing the welding point (3) into the focused laser light beam (4), into the position (B), outside the focussing point in order to carry out a preheating, and to keep the welding point (3) in the focused laser light beam and then at (C) to allow it to essentially coincide with the focusing point (5) in order to achieve a local melting, and the welding point further in the laser beam to hold it and then move it out of the focussing point into position (D) in order to anneal the welding point, 2. The method according to claim 1, characterized marked that the welding point is initially brought into the converging part of the laser light beam (4) and then after passing through the focusing point (5) is brought into the diverging part of the laser light beam, 3. The method according to claim 1, characterized marked that the welding point is between the place (B) where preheating takes place and the place (D), at which the annealing takes place, is shifted essentially according to the Achao dos laser light bundle, 2 0 Q 8 I 4 / Hl 0 8 Blank page