JPH0663778A - Method for cutting steel plate - Google Patents

Abstract

PURPOSE:To shorten a cutting line and to prevent a cutting trouble with a laser beam cutting machine. CONSTITUTION:A laser beam cutting machine is arranged on the upper side of a steel plate 4, the steel plate 4 is cut while controlling the moving direction of a torch of the laser beam cutting machine and cut to plural steel plates. The cutting line of the steel plate to be cut to plural steel plates is made in common. The movement of the torch 5 of the laser beam cutting machine is controlled in the order of cutting without generating the deformation in the cutting time. The frequency of the laser beam 8 emitted from the torch 5 is controlled corresponding to the cutting condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting a steel sheet with a laser cutting machine to cut out a plurality of steel sheets.

[0002]

Laser cutting machines are used to cut steel sheets. FIG. 1 is a perspective view showing an example of a laser cutting equipment (laser cutting line) for a steel plate on which a laser cutting machine is arranged. As shown in the drawing, a laser cutting machine 2 is movably arranged above a steel plate 4 placed on an upper surface of a belt conveyor 3 of a laser cutting facility 1. The moving direction of the torch (not shown) of the laser cutting machine 2 is controlled, and the steel plate is cut into a desired shape. As a laser cutting machine for steel plates, for example, a carbon dioxide laser cutting machine is used. The scrap after cutting is carried downstream by the belt conveyor 3. All management of the equipment is performed by a line control computer installed in the central control room 6.

[0003] Generally, for cutting a steel sheet, a method that does not have a common cutting line called one-stroke cutting (cutout cutting) (hereinafter referred to as "one-stroke cutting") and a common cutting line called common cutting are common. The method (hereinafter, referred to as "common disconnection") has been conventionally used. FIG. 2 is a plan view showing an example of a cutting line for one-stroke cutting, and FIG. 3 is a plan view showing an example of a cutting line for common cutting. As shown in FIG. 2, in the one-stroke cutting, the cutting lines 7 are separated and the steel plates are cut out one by one. On the other hand, as shown in FIG. 3, the common cutting has a common cutting line 7 crossed at the center.

When a steel sheet is cut by using a laser cutting machine, one-stroke cutting has been conventionally performed, and common cutting is hardly performed.

[0005]

The conventional cutting method using a single stroke for cutting with a laser cutting machine is described below.
It has the following problems.

As can be seen by comparing FIGS. 2 and 3, the one-stroke cutting has a longer cutting line than the common cutting because there is no common part in the cutting line.

Problems due to piercing occur frequently. That is, the one-stroke cutting requires punching (piercing) on the surface of the plate in order to start cutting from the inside of the plate, but in the laser cutting machine, there is a high probability that piercing will fail.

Since there is no common cutting line, the portion between the cut steel plates (between cutting lines) is scrap (9 shown in FIG. 2).
Will be.

The scrap remaining after laser cutting needs to be manually processed by gas cutting.

There is a problem that the burning phenomenon occurs. That is, at the cutting corners and sharp corners,
There is a problem that the sharpening of the cutting line reduces the speed of the torch, heat is concentrated on that part, and the burning phenomenon suddenly melts down at the cutting part.

For this reason, it has been considered to use the common cutting also in the laser cutting machine. However, in common cutting, in order to make the cutting line common, the cutting order may be such that the torch straddles the already cut cutting line. At this time, a burning phenomenon easily occurs and a cutting trouble occurs. There is a problem.

Therefore, an object of the present invention is to solve the above problems, to provide a method for cutting a steel sheet by a laser cutting machine which can shorten the cutting line, has no cutting trouble, and has a small amount of scrap. .

[0013]

According to the present invention, a laser cutting machine is arranged above a steel plate, and while controlling the moving direction of a torch of the laser cutting machine, the laser cutting machine cuts the steel plate into a plurality of sheets. In the method of cutting a steel sheet by a laser cutting machine for cutting out into the steel sheet, the laser cutting machine has a common cutting line to be cut into the plurality of steel sheets, and the cutting order is such that no deformation occurs in the plurality of steel sheets cut at the time of cutting. Of controlling the torch movement and controlling the frequency of the laser light according to the cutting conditions.

[0014]

The operation of the torch of the laser cutting machine is controlled by using a common cutting with a common cutting line and using a cutting order that minimizes the deformation of the steel plate when cutting by the common cutting. The cutting order is controlled by a computer. The cutting order teaching software teaches the cutting order and how to cut the nesting of the common cutting line according to the steel plate to be cut while controlling the moving direction of the torch while looking at the nesting screen. To do.

Next, control of the cutting mode of the laser cutting machine will be described with reference to the drawings. In the laser cutting machine, for example, it is possible to control the frequency of the laser light by determining what percentage is used while generating a pulse of 1000 Hertz in 1 second. This is because if the pulse is applied too much or suppressed too much, a cutting failure will result. In the present invention, the frequency of the laser light of the laser cutting machine is configured to be controllable to either the high speed cutting mode or the pulse cutting mode.

In the pulse cutting mode, the frequency of the laser light generated in one second is suppressed, and, for example, about 10% of the suppressed pulse is used. The pulse cutting mode, in which the frequency of the laser light is suppressed, is used for cutting where the burning phenomenon easily occurs. On the other hand, the high-speed cutting mode in which the frequency of the laser light is high is used for a cutting portion such as a straight portion where the burning phenomenon is not considered to occur normally.

FIG. 4 is an explanatory view of a method for preventing the burning phenomenon. As shown in FIG. 4, about 2 mm from the end surface of the steel plate 4.
A pulse cutting mode is used at a position at a distance of about mm (indicated by "A" in FIG. 4), and a high-speed cutting mode is used in subsequent inner portions (indicated by "B" in FIG. 4). . The arrow in FIG. 4 indicates the moving direction of the torch 5. In the laser cutting machine used for cutting the steel sheet, the diameter of oxygen gas, that is, the diameter of the torch 5 is about 2 mm, and the diameter of the laser beam 8 is about 0.2 mm. In the pulse cutting mode, the frequency of the laser beam used for one second is kept extremely low and the steel sheet is once grooved. As a result, the laser light is in the groove and does not spread to the left and right, so that the steel plate does not melt down due to heat.

As described above, when the torch straddles a corner portion and an acute angle portion, or a cutting line that has already been cut, the cutting speed is high by controlling the frequency of the laser light and cutting in the pulse cutting mode. Although it is lower than the mode, it can prevent the burning phenomenon and avoid cutting trouble.

On the other hand, in the high speed cutting mode, for example, about 75% of 1000 hertz is used for one second to cut at high speed.

By using the common cutting, scrap is not generated between the steel plates partitioned by the common cutting line. Further, since the common cutting starts from the outside of the steel sheet, piercing is not performed in the present invention.

[0021]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 5 is a partially omitted plan view showing a cutting order of steel plates by a laser cutting machine. In FIG. 5, 7 is a cutting line. The arrow described on the cutting line 7 indicates the cutting direction. Also, an arrow 10 written near the cutting line 7
Shows the direction of movement of the torch (not shown) of the laser cutting machine. That is, the torch moves from the starting point (indicated by “S” in FIG. 5) in the order of cutting numbers,
The steel plate 4 shown in FIG. 5 is cut and returned to the starting point.
During the cutting, the torch appropriately moves to the outside of the steel plate 4 as indicated by the arrow in FIG. Then, again, the steel plate 4 is returned from the outside to the inside and the cutting is started again.

At a cutting portion where a burning phenomenon is not considered to occur normally, such as a straight portion, cutting is performed in the high speed cutting mode. On the other hand, when the cutting line shown in FIG. 5 passes through the corner portion and the acute angle portion, or when the torch straddles the already cut cutting line, the cutting is performed by controlling the frequency of the laser light in the pulse cutting mode. This allows
Burning phenomenon was prevented and cutting trouble was avoided. Further, as shown in FIG. 5, the scrap 9 generated by cutting becomes a small piece, which is advantageous for recovery after cutting.

[0023]

As described above, according to the present invention, the following useful effects are brought about. Since the common cutting is used, the cutting line is shorter than the one-stroke cutting. There is no need to perform piercing because cutting can always be started from the outside of the steel plate. Since the cutting lines are common, there is no scrap between the cut steel plates (between the cutting lines). By making it possible to control the frequency of the laser light,
It is possible to avoid the occurrence of defective cutting due to the burning phenomenon.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a laser cutting facility for steel sheets.

FIG. 2 is a plan view showing an example of a cutting line for one-stroke cutting.

FIG. 3 is a plan view showing an example of a common cutting line.

FIG. 4 is an explanatory diagram of a method for preventing the burning phenomenon.

FIG. 5 is a partially omitted plan view showing a cutting order of steel plates by a laser cutting machine according to an embodiment of the present invention.

[Explanation of symbols]

 1 Laser cutting equipment 2 Laser cutting machine 3 Belt conveyor 4 Steel plate 5 Torch 6 Central control room 7 Cutting line 8 Laser light 9 Scrap 10 Arrow.

Front Page Continuation (72) Inventor Seiji Takahata 1-2, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. In the company

Claims (1)

[Claims] 1. A laser cutting machine is arranged above the steel plate,
In a method for cutting a steel sheet by a laser cutting machine, which cuts the steel sheet by the laser cutting machine to cut out into a plurality of steel sheets while controlling the moving direction of the torch of the laser cutting machine, a cutting line to be cut into the plurality of steel sheets. Controlling the movement of the torch of the laser cutting machine according to a cutting sequence in which deformation does not occur in the plurality of steel plates cut at the time of cutting, and controlling the frequency of the laser light according to cutting conditions. A method of cutting a steel sheet by a laser cutting machine, which is characterized by