JP2002273593A - Laser cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrially advantageous laser cutter by keeping the moving precision or durability of the cutter as the result of reducing the range of sputtering during grooving. SOLUTION: The laser cutter having a cutting laser torch for cutting a steel plate by irradiating it with laser beams, a grooving laser torch positioned in front of the cutting laser torch in a cutting direction for grooving the surface of the steel plate and a gas jet nozzle which jets gas forward in the cutting direction from between the cutting laser torch and the grooving laser torch for removing the sputter generated from the groove is provided with a sputter collection plate 8 positioned in front of the grooving laser torch in the cutting direction to make the generated sputter collide with each other to deflect the sputtering direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser cutting apparatus for cutting a metal material such as a thick steel plate, which generally has an oxide layer or foreign matter adhered to the surface, by irradiating a laser beam.

[0002]

2. Description of the Related Art Generally, an oxide layer (scale) is formed on the surface of a thick steel plate. This is generated because oxidation of the surface proceeds while being left on the cooling floor after finish rolling at a high temperature. Plates are usually traded with scales, since they serve to block the atmosphere and the steel plate and prevent further oxidation of the plate body.

[0003] Thick steel plates are flat products, and the producers cut them to the dimensions required by customers and ship them. The cutting means at this time includes, for example, shear cutting and gas cutting. recent years,
Laser cutting, because of its high cutting speed and adaptability to automation,
Attention has been paid to plasma cutting. Among them, laser cutting has favorable features such as cutting accuracy, narrow cutting margin (kerf width), and dross-free (the molten material does not adhere to the lower part of the material to be cut). Accompanying
It is also spreading in the field of thick plates.

[0004] Conventionally, laser cutting has been effective in the field of thin sheets having relatively clean surface properties. In particular, it was described that the power saving effect by the automatic operation and the omission of the post-process was great.
However, in general, the thickness of a thick plate is not always clean or uniform. Due to such unevenness of surface texture, cutting defects such as scrambled cross section and dross adhesion of thick plates have occurred, and the superiority of laser cutting such as automatic operation and omission of post-process is significantly impaired at present. It is.

Japanese Patent Application Laid-Open No. H10-27776 discloses a method for controlling cutting defects caused by non-uniformity of the surface properties.
Means such as Japanese Patent Publication No. 3 is disclosed. This is a method in which a small output laser beam is separately arranged in front of the main laser beam for cutting the steel sheet, and a groove is formed on the steel sheet surface online, and immediately after the main cutting of the following laser along the groove. This is a laser cutting method for cutting with a beam. The above method certainly has a very high resistance to cutting defects due to uneven surface properties of the slab.

[0006] However, practical problems have been found by subsequent experiments by the present inventors. That is the scattering of spatter generated when grooves are formed by the preceding laser beam. Sputtering distance is about 1m to 2m. Considering the working environment at the site, it does not reach the path where workers can exist, but reaches the parallel movement rail of the cutting device, lowering the movement accuracy. Or the durability may be deteriorated.

[0007]

An object of the present invention is to reduce the amount of spatter that is scattered at the time of forming a groove, thereby maintaining the moving accuracy and durability of the cutting device and industrially advantageous. It is to make a break.

[0008]

Therefore, the present inventors have prepared spatter collecting plates of various shapes and examined the spattering. As a result, the spiral-shaped deflector was placed in front of the groove-forming torch. It was found that the arrangement method was the most convenient and suitable for the intended purpose. In other words, in this case, the sputter generated from the forefront of the groove processing gradually loses its speed while colliding with the inner wall of the collecting plate, thereby shortening the flying.

Therefore, the above-mentioned problems are (1) a laser torch for cutting a steel plate by irradiating a laser beam, and a laser torch for forming a groove positioned in front of the cutting direction of the laser torch and providing a groove on the surface of the steel plate. And a gas jet nozzle for ejecting a gas in the cutting direction forward from between the cutting laser torch and the groove forming laser torch to remove spatter generated from the groove, wherein the cutting of the groove forming laser torch is performed. 1. A laser cutting device comprising a sputter collecting plate positioned in front of a direction and deflecting a scattered direction by colliding generated spatter. (2) The direction of deflection of the sputter by the sputter collecting plate is set to a direction substantially parallel to the steel plate. (1)
The laser cutting method device according to the above. (3) The laser cutting device according to (2), wherein a cross section of the sputter collecting plate is formed in a spiral shape and is cylindrical. (4) The two spirally formed sputter collecting plates are joined at the spiral end outer surface, arranged symmetrically with respect to the laser cutting line and integrated to form one sputter collecting plate. (3) The laser cutting device according to (3). Can be solved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the gist of the present invention will be described with reference to the drawings to make it more detailed. Figure 1
FIG. 1 is a diagram showing the concept of an embodiment of the present invention. In this embodiment, a YAG laser (not shown) was used as a laser beam source for providing the groove 1. The present laser beam 2 is guided to a step index type optical fiber 3 having a core diameter of 800 μm, and a light collecting head 4 having a one-to-one image forming optical system is provided at an emitting end of the fiber 3 so as to be focused on the surface of a steel plate 5. Irradiate. Then, a gas jet is sprayed from the gas jet nozzle 6 toward the irradiation point in the direction in which the groove processing proceeds, and the molten steel is removed. Air was used as the gas.
The opening diameter of the air jet nozzle 6 is 2.5 mm and the original pressure is 0.1 mm.
5 MPa, the spray angle was 45 °, and the distance between the irradiation point and the nozzle opening was 10 mm. The relative movement speed between the light-collecting head 4 and the steel material 5 was 1.0 m / min. The YAG laser was operated continuously. YAG laser power on steel 5 is 120
W. At this time, the depth of the groove is 150 μm and the width is 8
It became 00 μm. The melted steel is discharged from the groove by the air jet and scatters forward as spatter. Spattering was about 1-2 m.

As shown in FIG. 1, in the present invention, a spiral-shaped sputter collecting plate 8 supported by a stay 7 is provided in front of a condensing head 4 for providing grooves. The material of the stay 7 and the sputter collecting plate 8 was aluminum. Stay 7 is length 2
A round bar having a thickness of 0 mm and a thickness of 3 mm was used. The sputter collecting plate 8 has a structure in which two spiral shapes are combined. 3 vertical edges
0 mm, and the length of the spiral part on one side is 120 mm. Groove 1
The spatters generated from the air are scattered forward by the air jet and enter the sputter collecting plate 8. Then, while colliding inside the sputter collecting plate 8 and changing its direction, the collision is repeated one after another, and the speed is lost to stop. If the spiral is made to gradually converge, the spatter can be surely dropped into the collecting plate 8. The spiral part may be formed into a tubular shape and then unwound. The shape may be a smooth curved surface as shown in FIG. 1 or a polygon. In addition to the method of placing the sputter collecting plate, it is physically possible to wind the spatter in a direction perpendicular to the direction other than winding it so as to deflect the sputter in a direction substantially parallel to the steel plate as shown in FIG. But,
In that case, the sputter is blown up toward the top, and as a result, the sputter drops in the direction of the groove processing, which may obstruct the subsequent processing. Therefore, it is preferable that the shape be deflected in the lateral direction as shown in FIG. However, it may be curved in a torus shape or a lid may be provided on the sputter collecting plate.

In this embodiment, a YAG laser is used as a laser for providing grooves, but another laser having the same level of output can be used. The material of the stay 7 and the sputter collecting plate 8 is not limited to aluminum as long as it is nonflammable. In FIG. 1, reference numeral 9 denotes a cutting laser beam for performing the main cutting;
Is a calf, and 11 is dross generated at the time of cutting.

[0013]

As described above, in the cutting using the laser cutting device according to the present invention, it is possible to reduce the spattering of the spatter scattered at the time of providing the groove, and as a result, to maintain the moving accuracy and durability of the cutting device. Thus, an industrially advantageous laser cutting means can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing the concept of one embodiment of a laser cutting device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Groove formed in steel plate surface 2 Laser beam for groove formation 3 Optical fiber 4 Condensing head 5 Steel plate 6 Air jet nozzle 7 Collection plate support stay 8 Collection plate 9 Cutting laser beam 10 Calf 11 Dross

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Yamamoto 20-1 Shintomi, Futtsu-shi, Chiba F-term in the Technology Development Division of Nippon Steel Corporation (reference) 4E068 AA05 AE00 CG00 CG05 DA14 DB01

Claims (4)

[Claims] 1. A cutting laser torch for irradiating a laser beam to cut a steel sheet, a groove forming laser torch provided in front of the cutting laser torch in a cutting direction and providing a groove on a steel sheet surface, and the cutting laser torch. In a laser cutting apparatus having a gas jet nozzle that ejects gas forward in the cutting direction from between the groove forming laser torch and removes spatter generated from the groove, the gas cutting nozzle is located in front of the groove forming laser torch in the cutting direction, A laser cutting device comprising a sputter collecting plate for colliding generated spatter to deflect the scattering direction. 2. The laser cutting method device according to claim 1, wherein the direction of deflection of the sputter by the sputter collecting plate is substantially parallel to the steel plate. 3. The laser cutting apparatus according to claim 2, wherein a cross section of the sputter collecting plate is formed in a spiral shape and is cylindrical. 4. The two sputter collecting plates formed in a spiral shape are joined at the outer surface of the spiral end portion, and are arranged symmetrically with respect to a laser cutting line to be integrated into one sputter collecting plate. The laser cutting device according to claim 3, wherein: