JPH091374A - Machining head for welding in laser beam machine - Google Patents

Abstract

PURPOSE: To join an aluminum alloy, in which spatter or blowholes are easily produced, with a superior appearance and with a weld bead free of internal flaws while stain is suppressed on the converging lens. CONSTITUTION: On the side for converging laser beams 3 from the converging lens 2 of a machining head 1 for welding, a shield gas blowing hole 8 is provided which blows a shield gas transversely like an air-curtain over the entire inner side of a cylindrical member 5; and also, on the side oppositely facing the shield gas blowing hole 8, a shield gas discharging hole 10 is provided; thereby preventing the converging lens 2 from being stained by flying spatter, with a large amount of shield gas blown in from the blowing hole 8. In addition, by discharging the shield gas from the discharging hole 10, a jetting speed is adequately adjusted on the shield gas jetting from a machining head nozzle 6, enabling even an aluminum alloy to be joined with a superior appearance and with a weld bead free of internal flaws.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a welding processing head in a laser processing machine, and in particular, spatters and blowholes are generated even though it has an excellent function of preventing contamination of a focusing optical system. The present invention relates to a welding processing head in a laser processing machine that makes it possible to obtain a welded portion with few defects even with an easy aluminum alloy.

[0002]

2. Description of the Related Art A welding processing head in a conventional typical laser beam machine is constructed as shown in FIG. 4 which is a longitudinal sectional view thereof. That is, the lens holder 4 is provided inside the tubular member 5 of the welding processing head 1 and supports the condenser lens 2 which is a condenser optical system for condensing the laser light 3. Further, a processing head nozzle 6 is provided at the tip of the tubular member 5, and the laser beam 3
Is configured to be condensed by the condensing lens 2 so as to connect the condensing point 7 directly below the processing head nozzle 6. Further, a shield gas blowing hole 8 is provided between the condensing lens 2 of the tubular member 5 and the processing head nozzle 6 to supply a shielding gas such as argon or helium which is ejected from the processing head nozzle 6. The shield gas sprayed from the processing head nozzle 6 shields the weld from the outside air to prevent oxidation and defects in the weld, and controls the state of the plasma formed directly above the weld, and further the welding fumes. And the like to prevent the welding head 1 from entering the welding processing head 1.

However, in high power laser welding and welding of aluminum alloys by laser light, which have been increasingly diversified in recent years, spatter and fumes are severely generated in the welded portion, and light is condensed by a condenser lens or the like. There are problems such as instability of welding results and reduction of life of optical parts due to output reduction due to contamination of optical system. A welding processing head of a laser beam processing machine capable of preventing the condensing optical system from being contaminated by such a spatter is disclosed in, for example, Japanese Patent Application Laid-Open No. 59-223191 and Japanese Patent Application Laid-Open No. 1-107994.
Japanese Patent Laid-Open No. 6-122089 and the like.

First, a welding head for a laser beam machine disclosed in Japanese Patent Laid-Open No. 59-223191 is shown in a sectional view of FIG. 5 (a) and a section taken along line BB of FIG. 5 (a). As shown in FIG. 5B, the tip of the processing main body 1 which is a welding processing head is provided with a lens protecting gas such as air or nitrogen from the nozzle hole 21a provided on the inner surface thereof to the condenser lens 5.
A lens protecting nozzle 21 is attached which crosses the optical axis of No. 2 and flows out at a high flow rate to protect the condenser lens 5 from spatter during welding. This lens protection nozzle 21
The nozzle hole 21a of the nozzle is, for example, as shown in FIG.
The planar shape is almost fan-shaped, and the lens protecting gas covers the entire lens surface of the condenser lens 5. In addition, a shield gas supply nozzle 22 for supplying a shield gas such as argon gas to the welding point of the material to be welded at a relatively slow flow rate is provided in the vicinity of the focusing point 4a of the laser light 4, and the shield gas supply nozzle 22 is provided. Are joined and fixed to the processing head body 1 by a joining member 23. Therefore, the nozzle hole 21a of the lens protection nozzle 21
By the lens protecting gas flowing out from the condenser lens 5
Since the spatter flying toward the air is blocked, the condensing lens 5 is prevented from being contaminated, and the shield gas supply nozzle 2
Since the welding point of the material to be welded is covered with the shielding gas flowing out from the welding target 2, welding can be performed without any trouble.

A welding head of a laser beam machine disclosed in Japanese Patent Laid-Open No. 1-107994 is shown in a sectional view of FIG. 6 (a) and a sectional view taken along line CC of FIG. 6 (a). 6
Describing with reference to (b), reference numeral 1 is a welding head which is a welding processing head, and a condenser lens 2 arranged above the welding head 1 welds a laser beam 5 to a welding member 3.
The welding is performed by focusing on the butt surface of No. 3 and melting the butt portion of the moving welding member. Air passing through the gas discharge pipe 6 provided on the left side wall of the welding head 1 is blown into the welding head 1 through the gas discharge nozzle 8, and this air passes through the gas suction holes 9 and the right side wall of the welding head 1. It is sucked out from the gas suction pipe 7 provided in the. A large number of gas discharge nozzles are provided in one row in the lateral direction.
Has a flat shape extending in the lateral direction, the air flow flowing from the gas discharge nozzle 8 to the gas suction hole 9 becomes a film, and the film-like air flow causes spatter generated during welding into the welding head 1. Entry is blocked. The left-side pipe whose opening is directed to the focal point 4 of the laser beam 5 is an atmosphere gas discharge nozzle 10 for spraying a shield gas to the welding point, and the right-side pipe is an exhaust pipe 11.

The welding processing head of the laser processing machine disclosed in Japanese Patent Laid-Open No. 6-122089 will be described with reference to FIG. 7 which is an enlarged longitudinal sectional view of the main part of the welding processing head. A spatter guard 11 having an opening 12 through which the laser light L passes is arranged apart from each other, and an air curtain that is substantially orthogonal to the laser light L and covers the upper side of the opening 12 is formed. A flat nozzle for the working gas is formed. Further, on the upper surface of the spatter guard 11, there is a guide groove 13 for the gas for preventing spatter entry.
Are formed. Therefore, most of the spatter from the welded portion 2 is scattered by the sputter guard 11 in the direction of the welding processing head 1, and the portion scattered through the laser light passage opening 12 is also air curtain. Blocked by. It should be noted that what is obliquely arranged below the sputter guard 11 is a shield gas nozzle 9 for injecting a shield gas onto the welded portion 2.

[0007]

By adopting the sputter shielding means as described above, the problem of preventing contamination of the condenser optical system such as the condenser lens is considerably improved. However, it is very difficult to ensure good quality of the welded portion of the material to be welded, while preventing the condensing optical system from being contaminated by the spatter. For example, aluminum alloy has the characteristics that the molten metal is lighter in weight than other general steel materials, has good fluidity, and is easily oxidized, so spatter easily occurs during laser welding, and blowholes are also likely to occur. Is also likely to occur.

Therefore, even if the shape of the shield gas nozzle for blowing the shield gas, which is separately provided in the vicinity of the welded portion, and the gas flow rate are variously examined, the appearance of the weld bead and the internal defect of the weld bead are It was difficult to obtain a weld having the quality as obtained by welding using the typical welding processing head described with reference to FIG. In other words, adding a function that can reliably prevent the condensing optical system from being contaminated to a typical welding processing head that injects a shield gas from the processing head nozzle makes it possible to obtain a high quality product with excellent appearance and no internal defects. It is preferable for obtaining a weld bead.

Therefore, it is an object of the present invention to provide a welded portion having few defects even with an aluminum alloy which is prone to spatter and blowholes even though it has an excellent contamination preventing function for the condensing optical system. It is an object of the present invention to provide a welding processing head in a laser processing machine that makes it possible to obtain the same.

[0010]

Therefore, in order to solve the above-mentioned problems, the means adopted by the welding processing head in the laser beam machine according to claim 1 of the present invention is characterized in that the tubular member is A welding processing head in a laser beam machine, comprising a condensing optical system for condensing a laser beam inside, and a machining head nozzle on the tip side of the tubular member. A shield gas injection hole for injecting a shield gas for welding in an air curtain shape is provided between the optical system and the condensing point of the laser light in a direction traversing the entire inner side of the tubular member.

Further, a feature of the means adopted by the welding processing head in the laser processing machine according to claim 2 of the present invention is that the welding processing head in the laser processing machine according to claim 1 is characterized in that A shield gas discharge hole for discharging the gas blown from the shield gas blow hole is provided on the side of the strip-shaped member opposite to the shield gas blow hole.

The means adopted by the welding processing head in the laser processing machine according to claim 3 of the present invention is characterized in that in the welding processing head in the laser processing machine according to claim 2, the shield is provided. A gas flow rate adjusting valve is installed in a shield gas exhaust pipe communicating with the gas exhaust hole.

[0013]

With the welding processing head in the laser beam machine according to claim 1 of the present invention, a larger amount of shield gas is blown into the tubular member from the shield gas blowing hole.
A shield gas can be jetted from the processing head nozzle to the welded portion of the material to be welded, and spatters or the like scattered toward the focusing optical system can be blocked.

According to the welding processing head of the laser beam machine of the second aspect of the present invention, a larger amount of shield gas is blown into the cylindrical member from the shield gas blowing hole to remove the material to be welded from the processing head nozzle. A shield gas can be injected to the welded portion, spatters scattered toward the condensing optical system can be blocked, and the shield gas blown into the tubular member can be discharged from the shield gas discharge hole. The amount of shield gas sprayed from the processing head nozzle to the welded portion can be made equal to the amount of shield gas sprayed from the processing head nozzle according to the typical conventional example.

According to the welding processing head of the laser processing machine of the third aspect of the present invention, a larger amount of shield gas is blown into the cylindrical member from the shield gas blowing hole to remove the material to be welded from the processing head nozzle. A shield gas can be injected to the welded part, spatters scattered toward the condensing optical system can be shielded, and a gas flow rate control valve installed in a shield gas discharge pipe communicating with the shield gas discharge hole. The amount of shield gas discharged from the processing head nozzle to the welded portion can be easily adjusted by adjusting the opening degree of the shield gas and adjusting the amount of shield gas discharged from the shield gas discharge hole.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A welding processing head in a laser beam machine according to an embodiment of the present invention will now be described with reference to FIG. 1 which is a longitudinal sectional view showing the main part thereof and FIG. 2 which is a sectional view taken along the line AA of FIG. It will be explained with reference to FIG.

Reference numeral 1 shown in FIG. 1 is a welding processing head.
The welding processing head 1 includes a tubular member 5 having a shield gas blowing hole and a shield gas discharging hole, which will be described later, and a ring-shaped lens holder 4 provided on an inner wall of the tubular member 5. A condenser lens 2 which is a condenser optical system for condensing the laser beam 3 and is fitted in a groove provided on the inner periphery of the lens holder 4, and a process provided on the lower end of the tubular member 5. It is composed of a head nozzle 6. By the way, in this embodiment, the condensing lens 2 is used as the condensing optical system, but the condensing optical system may have a parabolic mirror or the like. In addition, reference numeral 7 is a condensing point of the laser light 3 condensed at the focal point of the condensing lens 2, where the welding of the workpiece W is performed.

As shown in FIG. 2, a plurality of shield gas blowing holes 8 are provided in the circumferential direction of the tubular member 5 (six in this example).
Shield gas supply nozzles 9 that are arranged and are flat in the circumferential direction of the tubular member 5 and have a fan-shaped shape in the AA cross section are connected to the shield gas blowing holes 8. Further, there is one shield gas discharge hole 10, and a shield gas discharge pipe 11 in which a gas flow rate adjusting valve 12 is interposed communicates therewith. Although a plurality of shield gas blowing holes 8 are provided in this example, for example, as shown in FIG. 3 of the cross-sectional view of the welding processing head, one flat long member extending in the circumferential direction of the tubular member 5 is provided. The shield gas blowing hole 8 may be used.

The mode of operation of the welding processing head in the laser processing machine having the above-described structure will be described below. When welding the workpiece W, the shield gas is supplied from the shield gas supply nozzle 9 through the shield gas blowing hole 8. It is blown into the tubular member 5. A part of the blown shield gas is passed through the shield gas discharge hole 10 and the shield gas discharge pipe 1
While being discharged from 1, the other shield gas is sprayed from the processing head nozzle 6 to the welded portion of the workpiece W.

The laser welding of the material W to be welded causes the spatter to be scattered from the welded portion, and a part of the spatter enters from the opening of the processing head nozzle 6 and tries to fly to the condenser lens 2, but the shield gas is supplied. By blowing a large amount of shield gas from the nozzle 9 into the tubular member 5, spatter is effectively shielded. As described above, even if a large amount of shield gas is blown into the tubular member 5 from the shield gas blowing hole 8, the opening amount of the gas flow rate adjusting valve 12 is adjusted so that the amount of the shield gas discharged from the shield gas discharge pipe 11 is adjusted. By adjusting, the shield gas amount injected from the processing head nozzle 6 to the welded portion of the workpiece W corresponds to the material of the workpiece W that is excellent in appearance and suitable for forming a weld bead without internal defects. The amount can be adjusted.

By the way, argon gas (60 liters / min), which is a shield gas, is blown into the cylindrical member 5 through the shield gas blowing hole 8 and the opening of the gas flow rate adjusting valve 12 is adjusted so that the argon gas from the machining head nozzle 6 is discharged. The injection speed of the gas was adjusted to 10 m / s, the aluminum alloy (A5052) plate was moved at a speed of 2 m / min, and welding was performed with the laser beam 3 of 3.5 kW. ,
10% of the case of a welding processing head according to a typical conventional example
It was suppressed to the following level, and the appearance and internal defects of the weld bead were the same, which was superior to the case of the welding processing head according to the conventional example equipped with the spatter shielding means. In this embodiment, as described above, the blowing direction of the argon gas is perpendicular to the optical axis of the laser beam 3, but when the argon gas is blown slightly downward, the spatter adheres to the condenser lens 2. It was recognized that the amount of sucrose decreased.

Therefore, even if the material to be welded is an aluminum alloy which is prone to spatter and internal defects,
There is less risk of instability of the welding result and reduction of the life of the optical parts due to the output reduction due to the contamination of the condenser lens, and the appearance defects and internal defects of the welding beads are also reduced. Therefore, a welded product having a weld bead that has an excellent appearance over a long period of time and has few internal defects can be obtained, which can greatly contribute to the improvement of the reliability of the welded product.

In the above description, the example in which the injection rate of the argon gas from the processing head nozzle 6 is adjusted by adjusting the opening of the gas flow rate adjusting valve 12 has been described. Even if the amount is fixed, the injection rate of the argon gas from the processing head nozzle 6 can be adjusted by adjusting the amount of the argon gas supplied from the shield gas supply nozzle 9.

Further, the shield gas discharged from the shield gas discharge pipe 11 may be recovered and reused such that it is mixed into a pipe communicating with the shield gas supply nozzle 9 from a shield gas supply source (not shown). It is possible. Further, like the welding processing head according to the conventional example provided with the spatter shielding means, a shield gas nozzle for injecting a shield gas can be separately provided at the welded portion of the material to be welded.

[0025]

As described above, according to the welding head of the laser beam machine of the first aspect of the present invention,
By blowing a larger amount of shield gas into the cylindrical member from the shield gas blowing hole, it is possible to block spatters or the like scattered toward the focusing optical system, and the laser beam machine according to claim 2 or 3 of the present invention. According to the welding processing head in, the shield gas blown into the tubular member is discharged from the shield gas discharge hole, so that the amount of the shield gas injected from the processing head nozzle to the welded portion of the workpiece is typically Since it is possible to make it equal to the amount of the shielding gas sprayed from the processing head nozzle according to the conventional example, even if the material to be welded is an aluminum alloy that is apt to cause spatter and internal defects, it is possible to collect There is less risk of instability in welding results and shortening of life of optical components due to reduction in output due to lens contamination, and there are also fewer defects in appearance and internal defects of the welding beads. Therefore, a welded product having a weld bead that has an excellent appearance over a long period of time and has few internal defects can be obtained, and there is a great effect that it can greatly contribute to the improvement of the reliability of the welded product.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a welding processing head in a laser processing machine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a transverse cross-sectional view of a welding processing head according to another embodiment of the present invention.

FIG. 4 is a vertical sectional view of a welding processing head in a typical laser processing machine according to a conventional example.

FIG. 5 relates to a conventional example disclosed in Japanese Patent Laid-Open No. 59-223191, FIG. 5 (a) is a sectional view of a welding processing head of a laser processing machine, and FIG. 5 (b) is FIG. 5 (a). ) BB
It is a line sectional view.

FIG. 6 relates to a conventional example disclosed in JP-A-1-107994, FIG. 6A is a sectional view of a welding processing head of a laser processing machine, and FIG. 6B is FIG. 6A. 6 is a cross-sectional view taken along the line CC of FIG.

FIG. 7 is an enlarged vertical cross-sectional view of a main part of a welding processing head of a laser processing machine according to a conventional example disclosed in Japanese Patent Laid-Open No. 6-122089.

[Explanation of symbols]

 1 ... Processing head for welding 2 ... Condensing lens 3 ... Laser light 4 ... Lens holder 5 ... Cylindrical member 6 ... Processing head nozzle 7 ... Focusing point 8 ... Shield gas blowing hole 9 ... Shield gas supply nozzle 10 ... Shield gas Exhaust hole 11 ... Shield gas exhaust pipe 12 ... Gas flow rate adjusting valve W ... Welding material

Claims (3)

[Claims] 1. A welding processing head in a laser processing machine, comprising: a condensing optical system for condensing a laser beam inside a tubular member, and a machining head nozzle on a tip end side of the tubular member. A shield gas injection hole for injecting a shield gas for welding in an air curtain shape in a direction traversing the entire inner region of the cylindrical member between the condensing optical system of the cylindrical member and a condensing point of laser light A processing head for welding in a laser processing machine, which is characterized by being provided with. 2. The shield gas discharge hole for discharging the gas blown from the shield gas blow hole is provided on the opposite side of the shield gas blow hole of the tubular member. Welding head for laser processing machines in Japan. 3. The welding processing head for a laser beam machine according to claim 2, wherein a gas flow rate adjusting valve is provided in a shield gas discharge pipe communicating with the shield gas discharge hole.