JPS62110885A - Laser welding method - Google Patents

Abstract

PURPOSE:To increase the welding speed with less reflectivity of the laser for the joining face and to automate the laser welding by taking the joining face subjected to the laser welding as the face having the crater by discharging or by coating a granular body on the joining face. CONSTITUTION:The components 9, 10 abutting the joining face each other are fixed with correct positioning on the table 6 which moves with numerical control in the X axial and Y axial directions which are at right angles each other, or on the rotary table 8 which is placed on the table 6. The absorptivity of the laser energy is made larger by having the crater by discharging on the joining face of the components 9, 10 in order to batter the absorption of a laser 20, or further by coating or pouring a granule on the joining face. The signal which controls with follow-up so as to make the laser irradiating position at right angles with the joining face all the time by detecting the magnetism thereof by magnetizing this granule itself and further by fixing the focus of the laser with the detector utilizing infrared supersonic wave is inputted to NC unit 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is a welding method using laser irradiation. □ [Prior art] Laser light oscillated from a laser oscillator is focused by a condensing lens, and is irradiated onto the workpiece while welding, cutting, grooves, etc.
Laser processing for creating recesses, surface cutting, etc. is well known and is currently used in various fields. Among these, in laser welding in particular, when the temperature of the metal surface rises due to laser irradiation, the laser absorption rate gradually increases, and as soon as melting begins, an evaporation phenomenon occurs.Furthermore, the reflection of the perforated wall surface causes the laser beam to penetrate deep into the metal. At the same time, it begins to penetrate into the wall surface. It is known that this J:Una laser welding can perform so-called keyhole welding in which welding progresses while applying energy directly to the bottom of the hole without relying on conduction heat of surface spot heat waves.

[Problem that the invention seeks to solve]

Laser welding has the advantage of forming a smooth, bulging bead due to Geeball welding, having little heat influence, and obtaining sufficient welding strength, but before this effective welding begins, When moving the laser beam to irradiate a new welding area, the irradiated laser 11
Most of the irradiated energy is reflected by the metal surface, and only a few percent of the irradiated energy is effectively utilized, which has the disadvantage of slowing down the welding speed.

In addition, when assembling metal parts without welding, the joint surfaces of each part are finished by cutting, etc.
Generally, the cut surfaces are finished with a file or scraper, or the polished surfaces are brought together and joined with bolts. When joining parts with bolts in this way, you can either provide a protruding 7-lunge part, pass the bolt through it, and tighten it with a nut, or make a through hole for the bolt in one part and use it. A screw hole is provided in one part, and a bolt passed through the bolt hole is screwed into the screw hole to fasten the parts. As described above, according to the conventional method of joining parts using bolts, it is necessary to provide a flange portion for passing the bolt and to process bolt holes and screw holes. Also, because of the shape of the part and the need for inserting a bolt, it was not possible to provide a structure above the hole into which the bolt was inserted to block it. For this reason, it has been desired to join parts by welding, but conventionally many parts have been welded manually, making it impossible to weld a large number of parts with the same shape. SUMMARY OF THE INVENTION An object of the present invention is to provide an automated laser welding method that increases the welding speed by reducing the laser reflectance on the joint surfaces of parts.

[Means for solving problems]

Therefore, when assembling parts, the present invention makes the joint surfaces of the parts a surface with craters created by electric discharge machining with low laser reflectivity, or injects metal or alloy powder into the joint surfaces. The laser absorption was increased by coating it. Also, it is applied by mixing an organic substance such as CMC or an activator such as borax or boric acid. Then, by magnetizing the powder itself or by magnetizing a mixture of magnetic powder, it is possible to easily apply it to the joint surface, and to control the laser to follow while detecting the magnetism. be able to do so.

When performing laser welding, each part to be assembled must be accurately held while numerically controlled in the X-axis and Y-axis directions at right angles to each other, and then perpendicular to the X- and Y-axis planes. It was mounted so that it could rotate around the R axis. On the other hand, the housing that holds the laser focusing lens rotates around the R' axis parallel to the X axis, and is slidably attached to the tip of an arm that moves up and down in the Z axis direction at right angles to the R' axis. , the numerical value in the axial direction of the housing itself! -The radius of rotation of the housing can be changed by setting the control limit to 1.

[Effect]

Parts whose joint surfaces are in contact with each other are accurately positioned and fixed on a table that is numerically controlled to move in X-axis and Y-axis directions perpendicular to each other, or on a rotary table placed on the table. The joint surface has a crater created by electrical discharge machining to improve laser absorption, or powder particles are coated or injected onto the joint surface to increase laser beam absorption. be.

The position of the bonding surface can be set at a position where the laser moves according to a program, or the laser can be irradiated by a conventional control method of playing back so that the laser moves along the bonding surface. A detector detects the magnetism and magnetic force of the magnetic powder coated or injected onto the surface, and a detector that uses infrared rays and ultrasonic waves determines the focus of the laser. A signal for follow-up control so as to be perpendicular to the NG device is input to the NG device. When welding is started according to a command from the NG device, the parts are moved on the table in the X-axis and Y-axis directions, or rotated on the rotary table. On the other hand, the housing that illuminates the laser is placed at the tip of the arm that moves up and down on the Z-axis.While rotating, the housing is used for synthetic movements such as changing the rotation radius. A laser is irradiated along the surface to perform C welding. Welding is faster than conventional laser welding by creating a joint surface with reduced C laser reflection due to electric discharge machining, or by reducing laser reflection on powder particles and improving energy absorption. It can be advanced quickly and the weld depth is adjusted within the keyhole depth that can be reached by the laser energy. Also, during welding, an inert gas such as argon is sprayed to prevent oxidation and at the same time prevent the laser from being absorbed by metal vapor.

〔Example〕

The present invention will be explained based on the drawings that illustrate the invention. In Fig. 1, an X-axis slide table 2 having a guide surface in the X-axis direction is fixed on a bed 1, and a servo motor 3 is used to move the
A saddle 4 that moves in the axial direction is attached. X on saddle 4
It has a guide surface in the Y-axis direction perpendicular to the axis, and a table 6 that is moved in the Y-axis direction by a servo motor 5 is mounted thereon. On this table 6, a table 8 that rotates and indexes by a servo motor 7 on an R axis perpendicular to the X and Y axes is removably attached, and parts 9 and 10 are positioned and fixed on it. do. A column 11 fixed to a bed 1 has a head 14 that is moved in the vertical Z-axis direction by a servo motor 12 and rotated by a servo motor 13, and a servo motor 15 is used to move the head 14 around the R' axis parallel to the X axis. A rotating arm 16 is provided.

A laser oscillator 17 is provided at the base end of the arm 16, and a housing 1 is provided at the tip end of the housing 1, which can be slid in a direction perpendicular to the R' axis by a servo motor 18 to change and adjust the radius of rotation.
9 is the setting. 21 is the servo motor 3 mentioned above,
5, 7, 12, 15.18, and an NC device (numerical control device) that controls the laser oscillator 17.

In FIG. 2, the portion explained in FIG. 1 will be explained in more detail. The screw 13 is engaged with a nut 22 fixed to the head 14 to move the head 14 up and down v1. A worm wheel 24 that meshes with a worm (not shown) provided on a shaft 23 rotated by a servo motor 15 is fixed to a shaft 25 with a nut 26, and the shaft 25 is connected to a bearing 28 enclosed in the head 14 with a plate 27. J: Rotatably supported. The arm 16 is attached to a disc 29 that is integrally provided with the shaft 25.
to fix. Laser oscillator 17 uses Japanese Patent Application Laid-Open No. 60-107.
, No. 877, No. 107,878, No. 107,
No. 880, No. 170,991, No. 115,2
The laser 20 emitted from the laser oscillator 17 changes its optical path by reflection @ 30, 31, is focused by the condensing lens 32, and is focused on the welded part of the part 9 and 10. do. The housing 19, which fixes the condensing lens 32 with a lens fixing member 33, is slidably held on the arm 16, and the sliding movement is controlled by a helical rack 34 that is fixed to the housing 19 and also serves as a slide key. This is done by rotating the helical gear 35 that meshes with the servo motor 18 via the shaft 36. IP of this housing 19! Parts 9 that change due to lj+,
Focus the laser on 10 welding locations.

The welding position of this part 9.10 is detected by a detector 38 attached to the nozzle 37, and the detection signal is input to the NC device 21 via an amplifier (not shown) or the like.
This is one of the signals that control each part. Although only one detector 38 is shown, the number is not limited to one, and a plurality of detectors 38 may be provided to accurately set the height, position, and direction of laser irradiation.

For example, the distance between the parts 9 and 10 and the condensing lens 32 can be determined by using infrared rays to detect the position where the infrared rays emitted by the molten metal are the most intense, or by using an ultrasonic detector.
To track the joint surface of the component 9.10, a magnetic sensor that detects the magnetism or magnetic force of magnetic powder on the joint surface can be used.

When powder particles are inserted into the joint surface and used by painting or adhering with tape, when the powder particles are magnetized and used, the absorption of laser energy is extremely large and effective welding is possible. It is something to do.

The powder particles can be coated with a mixture of an organic substance such as CMC, an activator such as borax or boric acid, and powder particles having magnetization ability.

Other powder particles include W, which can be obtained by reducing oxides.
, Wo, Fe, Ni, Co(7) powder, Cu, l'Ji powder that can be made by reduction from aqueous solution, Fe, l'Ji that can be obtained by thermal decomposition of metal carbonyl.
Cu powder, which can be obtained by electrolysis of molten salt,
Ao, [A powder, cemented carbide material powder obtained by crushing, and other alloys obtained by powdering by blowing water, air, inert PI gas, etc. into the molten metal flow flowing out of the nozzle. Powder can be used. Nozzle 37 through pipe 39
An inert gas such as argon is blown out from around the transmission relay 1f20 to prevent oxidation of the welded part and at the same time prevent the laser from being absorbed by metal vapor.

〔Effect of the invention〕

Is the joint surface to be laser welded exposed? The welding speed can be made similar to the welding speed by creating a surface with craters due to drilling or by applying powder or granular material to the joint surface to prevent formation of a retarder and improve the absorption of laser energy. was completed.

Also, the relative position of the parts to be joined and the laser is X.

Y axis, X, Y, Z axis or even X, Y, Z, R axis
By controlling C, welding can be automated,
Furthermore, by magnetizing the powder particles inserted into the joint surface and detecting the magnetism and magnetic force, it also has the effect of allowing the laser to follow the joint surface for welding.

6......table ８・・・・・・・・・Rotary table 9.10・・・・・・・Parts 16・・・・・・・・・Arm 17... Laser oscillator 19・・・・・・Housing 20......Laser Patent applicant

Claims (7)

[Claims] (1) A laser welding method in which each part to be assembled is accurately held by abutting a machined surface having a crater due to electrical discharge machining, etc., and welding by irradiating the abutting portion with a laser. (2) The laser welding method according to claim 1, wherein each part to be assembled moves under numerical control in the X and Y axis directions. (3) The laser welding method according to claim 1, wherein each part to be assembled moves under numerical control in the X, Y, and R axis directions. (4) Laser irradiation is in a plane parallel to the Z axis,
The laser welding method according to claim 1, wherein the laser welding method rotates around an R' axis parallel to the axis and controls the radius of rotation for irradiation. (5) The laser welding method according to claim 1, wherein the processed surface has powder grains that improve the absorption of laser energy. (6) The laser welding method according to claim 1, wherein the processed surface has magnetized powder grains that improve absorption of laser energy. (7) The laser welding method according to claim 1, wherein the laser irradiation detects and follows a machined surface having magnetized powder particles.