JP2623993B2 - Laser processing head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing head, and more particularly, to a laser processing head for stably welding a steel plate having been subjected to surface treatment such as galvanization.

[0002]

2. Description of the Related Art In recent years, laser beams have been focused and densified, and their application to metal or non-metal processing has been actively carried out. Particularly, as a joining means characterized by low distortion welding and high speed welding, a laser beam is used. The application of welding is increasing. On the other hand, the quality required for products is also increasing, and accordingly, changes in the materials to be welded are remarkable. For example, in the automotive industry, surface-treated steel sheets such as galvanized steel sheets are being actively used in order to improve corrosion resistance. However, from the viewpoint of welding, it is well known that the surface treatment material burns at the time of welding and generates welding defects such as blow holes. As a means for solving this welding defect, in the general field of arc welding, various measures such as changing the composition of a wire serving as a consumable electrode have been taken, but they have not yet become a decisive factor. Further, in the case of laser welding, it is an issue to eliminate welding defects particularly in the case of a lap joint. To solve this issue, conventionally, the following measures have been taken. That is, FIG. 7 is a cross-sectional view showing a conventional lap welding using a laser, showing a state where a predetermined gap g is secured between a pair of plate materials 1 and 2 and welding is performed by the processing head 3. By welding in this manner, the gas of the burned zinc layer enters the gap g and is further diffused to the periphery, so that it does not remain in the fused metal and does not generate welding defects.

[0003]

Conventionally, laser welding has been performed as described above. However, it is not always easy to ensure a uniform gap g depending on the size and shape of the object to be welded. There was a problem of lack of practicality.

[0004] The present invention has been made to solve the above problems, and has as its object to provide a laser processing head capable of performing stable laser processing of a surface-treated steel sheet or the like.

[0005]

According to a first aspect of the present invention, there is provided a laser processing head having a first nozzle for guiding a laser beam, and a desired gap interposed on the outer periphery of the first nozzle. A second nozzle, a small hole communicating the inside of the first nozzle with the gap, and an amount of the processing gas flowing into the gap through the small hole and into the tip of the first nozzle. Processing gas separation means for separating the
The air-permeable material filter is provided in the gap .

The laser processing head according to the second aspect of the present invention is such that a filter means of a gas permeable material is interposed between the processing gas separating means and the small holes.

[0007]

Further, a laser processing head according to a third aspect of the present invention includes a first nozzle for guiding a laser beam, and a second nozzle disposed around a periphery of the first nozzle with a desired gap.
Nozzle, processing gas supply means for supplying the processing gas to the gap, and a filter means of a breathable material which is located at the tip of the first nozzle and is detachably mounted.

[0009]

The working head according to the present invention supplies a shielding gas having a uniform flow velocity around a nozzle for guiding a focused laser beam, for example, to mitigate a reaction between a burned zinc layer gas and a molten metal. I do.

[0010] In addition, a filter means made of a gas-permeable material provided in the flow path of the shield gas controls the flow of the supplied shield gas to a uniform state.

[0011]

[Embodiment 1] FIG. 1 is a cross-sectional view showing a configuration of a laser welding working head according to a first embodiment of the present invention. In the figure, reference numeral 3 denotes a head main body that holds a condensing optical component 10 (indicated by a parabolic mirror in the figure), 11 engages with the head main body 3, and
A first nozzle for guiding the focused laser beam 12,
13 is a plurality of small holes radially machined on the slope 14 of the first nozzle 11, 15 is a predetermined length joined to the step 16 slightly below the small hole 13 inside the slope of the first nozzle 11. Is fixed to the outer periphery of the first nozzle 11 with screws 18, and the second nozzle , which forms a desired conical gap with the outer periphery of the first nozzle 11 , 30 is the first nozzle . Noz
Formed on the slope 14 of the nozzle 11 and the outer periphery of the cylindrical body 15.
It is a filter of a breathable material interposed in the gap .

In the laser welding processing head configured as described above, argon gas or helium gas is supplied as a processing gas to the head body 3 in order to eliminate plasma vapor generated at the tip of the first nozzle 11 during welding. That is known. The processing gas supplied to the head main body 3 is separated by the cylindrical body 15 and most of the processing gas is guided to the first nozzle 11 and injected into the weld metal. The remaining processing gas is supplied to the second nozzle 17 through the plurality of small holes 13 as a flow without disturbance in the filter 30 , and the laminar flow is generated from the outer periphery of the first nozzle 14. in it is released.

Embodiment 2 FIG. FIG. 2 is a sectional view showing a configuration of a laser welding working head according to a second embodiment of the present invention. In the figure, 20-2
2 is a step formed on the inner slope of the second nozzle 17;
Reference numerals 3 to 25 denote ring-shaped wire meshes which are mounted on the step portions 20 to 22, respectively, and have different inner and outer diameters. The other configuration is the same as that of the first embodiment, and the same reference numerals are given and the description is omitted.

In the processing head for laser welding configured as described above, the processing gas separated by the cylindrical body 15 is rectified by the ring-shaped wire meshes 23 to 25, and processed in the same manner as in the first embodiment. Acts on the processed part of the object.

Embodiment 3 FIG. FIG. 3 is a sectional view showing a configuration of a laser welding working head according to a third embodiment of the present invention. In the figure, 40 is a tip member which is fixed by the screw portion 41 formed at the tip of the first nozzle 11, as shown in a perspective view thereof in FIG. 4, a support piece 42 which is formed radially I have. 43
5 is a net-like structure whose perspective view is shown in FIG. 5, which is made of a heat-resistant material, and has a tip member 40 and a second nozzle 1.
7 supported. 44 is the first nozzle 1
Filter means 45 interposed in the gap formed by the first and second nozzles 17 is a pipe for supplying a shielding gas to the gap. Note that the filter means 44 is
6 is formed in a substantially conical shape as shown in a perspective view, and is manufactured by cutting a plate-shaped material having a property of foaming metal and allowing gas to pass through into a fan shape and forming a curved surface body. I have. In this FIG. 6 shows a combination of plural materials, may of course be formed integrally.

Although the embodiments of the present invention have been illustrated and described above, the present invention is not limited to these embodiments, and various design changes can be made without departing from the gist of the present invention.
Needless to say, the processing head according to the present invention can be used for all automatic welding apparatuses including a laser welding robot.

[0017]

As described above, according to the laser processing head of the present invention, the flow dividing means and the filter are used.
Divert part of the process gas as a shielding gas undisturbed Te
Results welded portion covering the periphery, and air involving for example zinc gas generated when welding galvanized steel, is relaxed reaction phenomenon between the weld metal, weld free from defects is obtained, a portion of the process gas It is not necessary to newly provide a supply port for the shield gas to divert the gas as the shield gas, and there is an advantage that the structure of the processing head is simplified.

According to another aspect of the present invention, a filter means of a gas permeable material is provided in a passage of a shielding gas whose main purpose is to block air, so that turbulence of a processing gas is suppressed and uniformity is achieved. Gas shield performance in a laminar flow state by the flow velocity can be obtained.

Further, during welding, so-called molten metal may be scattered as spatter, but the spatter adheres to the filter means and causes clogging, so that the flow rate of the shielding gas becomes uneven and the initial effect cannot be obtained. . Therefore, timely, it becomes necessary to replace the filter means, there is another advantage that replacement of the filter unit is facilitated by extremely According to the invention of the present invention.

[Brief description of the drawings]

1 is a cross-sectional view showing a machining head configuration for laser welding according to an embodiment of the first invention.

FIG. 2 is a sectional view showing a configuration of a processing head for laser welding according to an embodiment of the second invention.

FIG. 3 is a cross-sectional view showing a configuration of a working head for laser welding according to an embodiment of the third invention .

FIG. 4 is a perspective view showing a tip member used in the third invention .

FIG. 5 is a perspective view showing a filter means used in the third invention .

FIG. 6 is a perspective view showing another example of the filter means used in the third invention .

FIG. 7 is a diagram showing a conventional lap welding state using a laser.

[Explanation of symbols]

3 is a processing head body, 10 is a condensing optical component, 11 is a first
Nozzle, 12 is a laser beam, 13 is a small hole, 15 is a cylindrical body, 17 is a second nozzle, 20 is a step, 21 is a step,
22 is a step, 23 is a wire mesh, 24 is a wire mesh, 25 is a wire mesh, 3
0 is a filter, 40 is a chip member, 43 is a filter
And 44, a filter .

Claims (3)

(57) [Claims] 1. A laser processing head for processing a workpiece by irradiating a laser beam focused by a focusing means to a workpiece and supplying a processing gas to a processing section of the workpiece.
A first nozzle that guides the laser light, a second nozzle that is disposed on the outer periphery of the first nozzle with a desired gap interposed therebetween, and communicates with the inside of the first nozzle and the gap. A processing gas separating means provided in the first nozzle for separating the processing gas into the gap through the small hole into the gap and the processing gas into the tip of the first nozzle; A laser processing head including a filter means of a gas permeable material interposed in a gap. 2. A laser processing head for irradiating a laser beam condensed by a light condensing means to a workpiece and supplying a processing gas to a processing portion of the workpiece to process the workpiece.
A first nozzle that guides the laser light, a second nozzle that is disposed on the outer periphery of the first nozzle with a desired gap interposed therebetween, and communicates with the inside of the first nozzle and the gap. A processing gas separating means provided in the first nozzle for separating the processing gas into the gap through the small hole into the gap and the processing gas into the tip of the first nozzle; A laser processing head comprising a gas-permeable material filter means interposed between a processing gas separating means and the small hole. 3. A laser processing head for irradiating a laser beam condensed by a light condensing means to a workpiece and supplying a processing gas to a processing section of the workpiece to process the workpiece.
A first nozzle that guides the laser light, a second nozzle that is disposed on the outer periphery of the first nozzle with a desired gap interposed therebetween, and a processing gas supply unit that supplies the processing gas to the gap. A laser processing head which is provided at an end of the first nozzle and is provided with a filter means of a breathable material which is detachably provided.