JP7437245B2 - Laser cutting method - Google Patents

Description

The present invention relates to a corner laser cutting method that allows corners to be cut rationally when a figure including corners is laser cut by irradiating a laser beam toward a material to be cut.

Laser cutting methods are widely used in which a laser beam is irradiated toward the material to be cut, and an assist gas is injected along with the laser beam, or a shielding gas is injected along the assist gas to cut the material. has been done.

This laser cutting involves irradiating a laser beam from a nozzle attached to a laser torch toward the top surface of the material to be cut, and injecting an assist gas. This is done by removing the material and forming a kerf. Then, by moving the laser torch along a preset planned cutting line, a continuous kerf is formed along this planned cutting line to perform the desired cutting.

In this kind of cutting, there is a time lag between the reaction on the front side of the material to be cut and the reaction on the back side, and the cut surface formed on the material to be cut has a tendency to move backward from the cutting direction. A diagonal line (drag line) is formed.

Even if a diagonal drag line as described above is formed, it is not a big problem as long as the intended cutting line is a straight line. However, if there is a corner on the planned cutting line, even if the front side of the corner is cut at the desired angle, a delay in the drag line will be expressed on the back side, so it will not be cut at the desired angle. A problem arises.

Therefore, when cutting corners, the problem is how to eliminate the delay on the back side with respect to the front side. In order to solve this problem, the laser torch is cut by passing through the corner with one side of the corner cut, and then the laser torch is moved to cut from the extension line of the other side of the corner or from the corner. A cutting method has been proposed (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2016-068144

In the invention described in Patent Document 1, the corner can be cut at substantially the same angle from the front side to the back side. However, since the cutting area of the material to be cut is separated from the two sides forming the corner, there is a problem in that the area to be scrapped increases and the yield deteriorates.

When cutting a corner, the cutting speed is reduced to cut continuously, or the cutting is stopped once at the corner. In this case, if the heat input when cutting the corners is the same as the heat input when cutting the sides, there is a risk that the heat input will be excessive at the corners and self-burning will occur. For this reason, the cutting speed is reduced and the heat input is also reduced, but in this case, there is a problem that the cutting delay on the back side cannot be eliminated.

An object of the present invention is to provide a laser cutting method and a laser cutting device that can reduce the cutting delay on the back side when cutting the corners of a figure to be cut from a workpiece.

A typical corner laser cutting method according to the present invention is a laser cutting method in which a corner to be cut is cut when a material to be cut is irradiated with laser light and cut along a preset scheduled cutting line. As the corner to be cut is approached, the cutting speed is gradually decreased from the speed set in advance when cutting the material to be cut, and the heat input is set in advance when cutting the material to be cut. The heat input is gradually decreased from the gradually decreased heat input, and the cutting speed is gradually decreased before reaching the corner, while the heat input is gradually increased from the gradually decreased heat input, and when the corner is reached, the cutting speed is the lowest. and the gradually increased heat input is lower than the preset heat input, and after passing the corner, the cutting speed is gradually increased and the heat input is gradually decreased from the gradually increased heat input, and then gradually increasing the cutting speed to the preset speed and gradually increasing the heat input to the preset heat input, and increasing the heat input to the preset speed as the cutting speed reaches the preset speed. The feature is that the heat input is gradually increased up to a certain temperature.

Further, a typical laser cutting device according to the present invention is a laser cutting device that cuts a corner portion to be cut when cutting a material to be cut along a preset scheduled cutting line by irradiating a laser beam onto a material to be cut. The cutting condition storage unit stores cutting conditions including a cutting speed and laser conditions corresponding to the material and thickness of the material to be cut in advance, and a cutting condition storage unit that stores cutting conditions including cutting speed and laser conditions corresponding to the material and thickness of the material to be cut, and The cutting speed is controlled so that the cutting speed is gradually decreased from the preset cutting speed to the lowest when reaching the corner, and after passing the corner, the cutting speed is gradually increased to the preset cutting speed. and the heat input by the laser beam is adjusted to a preset heat input when cutting the material to be cut as the cutting speed gradually decreases as the cutting speed approaches the corner to be cut. , and before reaching the corner, the heat input is gradually increased compared to the gradually reduced heat input, and when reaching the corner, the heat input is lower than the preset heat input, and after passing the corner, a laser condition control unit that controls to gradually decrease the heat input from the gradually increased heat input, and then gradually increase the heat input to the preset heat input;
It has the following.

In the laser cutting method according to the present invention, when cutting a corner, it is possible to reduce the delay on the back side of the material to be cut. That is, when cutting the target material to be cut, the preset speed is gradually decreased as the corner approaches the corner, and the cutting speed is set to the lowest speed when the corner is reached. After that, the speed is gradually increased to a preset speed. Then, the heat input is gradually decreased as the cutting speed gradually decreases, is gradually increased before reaching the corner, is gradually decreased again after passing the corner, and is then gradually increased. Therefore, even though the cutting speed is at its lowest when reaching and passing the corner, the heat input is not at its lowest.

In this way, when passing through a corner, the heat input is higher than the cutting speed. This increases the relative cutting ability. Therefore, the heat input to the back side of the material to be cut is increased, and the delay in cutting that occurs on the back side can be reduced or eliminated.

Further, the laser cutting device according to the present invention can smoothly cut corners that exist when cutting a preset scheduled cutting line.

FIG. 1 is a diagram schematically explaining a laser cutting method according to the present invention. It is a figure explaining the change of cutting speed and the change of heat input when implementing the laser cutting method based on a present Example. It is a photograph comparing the back side of a workpiece cut by this example and the backside of a workpiece cut by a conventional laser cutting method. 1 is a diagram schematically illustrating a laser cutting device according to an embodiment. FIG. FIG. 2 is a diagram schematically illustrating the configuration of a control device that constitutes a laser cutting device.

Hereinafter, a laser cutting method and a laser cutting apparatus according to the present invention will be explained using FIGS. 1 and 4. The laser cutting method according to the present invention is a method for cutting a corner 2 included in a figure 1 to be cut set on a material to be cut A shown in FIG. Particularly, the corner 2 is cut in a substantially straight line from the front side to the back side by reducing or eliminating the cutting delay on the back side of the workpiece A at the corner 2 with respect to the front side. It is.

The laser cutting device according to the present invention includes a truck 21 that runs along a rail 20, and a transverse carriage 23 that runs on the truck 21 in a direction perpendicular to the rail 20. The truck 21 is driven by a travel motor 22, and the traverse carriage 23 is driven by a traverse motor 24. A laser torch 25 is disposed on the transverse carriage 23 so as to be movable up and down, and a laser oscillator 26 is connected to the laser torch 25. An operation panel 28 is disposed on the trolley 21, and a control device 29 for controlling the travel motor 22, the traverse motor 24, and the laser oscillator 26 is configured on the operation panel 28.

By controlling the traveling motor 22, the traverse motor 24, and the laser oscillator 26 of the laser cutting device configured as described above, the laser beam is irradiated from the laser torch 25 toward the material A to be cut, and the outline of the figure 1 to be cut is Cutting is performed by running the machine along the Then, in this process, the corner portion 2 is cut.

When cutting the corner portion 2, there is no limitation as to whether the cutting progresses in the order of the cutting line 3, the corner portion 2, and the cutting line 4, or the cutting progresses in the order of the cutting line 4, the corner portion 2, and the cutting line 3. Further, the cutting speed for the material to be cut A varies depending on conditions such as the thickness, material, or surface condition of the material to be cut, but is mainly set in accordance with the thickness of the material to be cut.

As shown in FIG. 2, since the cutting direction changes at the corner 2, the traveling speed (cutting speed) of the laser nozzle 25 is set to be the slowest when the laser nozzle 25 reaches the corner 2. However, the laser nozzle 25 does not stop running, and the cutting direction is changed while the cutting speed is gradually reduced. Therefore, the corner portion 2 has a slightly curved surface within an allowable range.

By controlling the heat input due to laser beam irradiation to the material A to be cut in response to changes in cutting speed, the edge formed by the surface defined by the cutting line 3 and the surface defined by the cutting line 4 that constitute the corner portion 2 can be cut. It is possible to configure it substantially vertically from the front side to the back side. That is, with the corner 2 as a reference, the separation distance from the corner 2, the time to reach the corner 2, or The time of separation from the corner 2 is set, and the cutting speed and heat input at each set point are controlled in correspondence.

As shown in FIG. 2, a plurality of positions S with respect to the corner 2 are defined as a position S3 at which the cutting direction starts to be changed from the cutting line 3 toward the corner 2, a separation distance from the corner 2, or a position S3 at which the cutting direction starts to be changed from the cutting line 3 toward the corner 2; The positions S03 and S04 are set at the time when the cutting direction is reached, and the position S4 is set at the time when the cutting direction is completely changed from the corner 2 toward the cutting line 4. Note that the spacing between the positions S is not uniquely set, but is set depending on the thickness of the material A to be cut, heat input conditions, and the like.

In this example, when the thickness of the material to be cut A is 12 mm, the distance from position S3 to position S03 and the distance from position S04 to position S4 are approximately 1.6 mm, or the time t1 is approximately 0.1 seconds, and the distance from position S03 to position S03 is approximately 1.6 mm. The interval from S03 to position S2 and the interval from position S2 to position S04 are set to approximately 0.8 mm, or time t2 is set to approximately 0.07 seconds. Further, when the thickness of the material to be cut A is 19 mm, the interval from position S3 to position S03 and the interval from position S04 to position S4 are approximately 1.5 mm, or the time t1 is approximately 0.1 second, and the interval from position S03 to position The interval to S2 and the interval from position S2 to position S04 are set to approximately 0.6 mm, or time t2 is set to approximately 0.06 seconds. Further, when the thickness of the material to be cut A is 25 mm, the distance from position S3 to position S03 and the distance from position S04 to position S4 are approximately 1.9 mm, or the time t1 is approximately 0.2 seconds, and the distance from position S03 to position The interval to S2 and the interval from position S2 to position S04 are set to approximately 0.5 mm, or time t2 is set to approximately 0.06 seconds.

The cutting speed V at each position S is set as speed V3 at position S3, speed V03 at position S03, speed V2 at position S2, and speed V04 at position S04. The speeds V3 and V4 set at the positions S3 and S4 are set as cutting speeds when cutting the material A to be cut. Further, the speed V2 set at the position S2 is set as the cutting speed when cutting the corner portion 2. Furthermore, the speeds V03 and V04 set at positions S03 and S04 are the cutting speed when passing through position S03 in the process of reaching speed V2 from speed V3, and the cutting speed passing through position S04 in the process of reaching speed V4 from speed V2. It is set as the cutting speed when cutting.

In this example, when the thickness of the material to be cut A is 12 mm, the speeds V3 and V4 are set to approximately 1100 mm per minute, the speed V2 is set to approximately 650 mm per minute, and the speeds V03 and V04 are set to approximately 850 mm per minute. has been done. Further, when the thickness of the material to be cut A is 19 mm, the speeds V3 and V4 are set to approximately 900 mm per minute, the speed V2 is set to approximately 550 mm per minute, and the speeds V03 and V04 are set to approximately 700 mm per minute. . Further, when the thickness of the material to be cut A is 25 mm, the speeds V3 and V4 are set to approximately 650 mm per minute, the speed V2 is set to approximately 450 mm per minute, and the speeds V03 and V04 are set to approximately 500 mm per minute. .

Heat input P due to laser beam irradiation at each position S is set as heat input P3 at position S3, heat input P03 at position S03, heat input P2 at position S2, and heat input P04 at position S04. Heat inputs P3 and P4 set at positions S3 and S4 are set as heat inputs when cutting material A to be cut. Further, the heat input P2 set at the position S2 is set as the heat input when cutting the corner portion 2. Furthermore, heat inputs P03 and P04 set at positions S03 and S04 reach heat input P4 from heat input P2 as heat input when passing through position S03 in the process of reaching heat input P2 from heat input P3. This is set as the heat input when passing through position S04 in the process.

In this embodiment, the heat input P due to laser beam irradiation is changed by controlling the duty. When the thickness of the material to be cut A is 12 mm, the heat inputs P3 and P4 are set to a duty of approximately 50%, the heat input P2 is set to a duty of approximately 41%, and the heat inputs P03 and P04 are set to a duty of approximately 35%. There is. In addition, when the thickness of the material to be cut A is 19 mm, the heat inputs P3 and P4 are set to a duty of approximately 75%, the heat input P2 is set to a duty of approximately 61%, and the heat inputs P03 and P04 are set to a duty of approximately 53%. has been done. Furthermore, when the thickness of the material to be cut A is 25 mm, the heat inputs P3 and P4 are set to a duty of approximately 65%, the heat input P2 is set to a duty of approximately 53%, and the heat inputs P03 and P04 are set to a duty of approximately 49%. has been done.

When we cut the workpiece A of each thickness using the above settings and compared the roundness on the front side and the roundness on the back side at corner 2, we found that although the roundness on the back side was slightly larger, it was sufficient. It is judged that it can withstand practical use. For example, in the case of a plate thickness of 19 mm, the roundness on the front side was approximately 700 μm, while the roundness on the back side was approximately 800 μm. Thus, it is sufficiently practical that the thickness is 19 mm and the difference in roundness between the front side and the back side is 100 μm.

FIG. 3 shows the back side of a workpiece cut by the laser cutting method according to the present invention (FIG. 3(a)) and the backside of a workpiece cut by the conventional laser cutting method (FIG. 3(b)). FIG. As shown in the figure, it is clear that the roundness of the back surface of the corner cut by the laser cutting method of the present invention is smaller than the roundness of the back surface of the corner cut by the conventional laser cutting method.

In the above embodiment, the heat input to the material A to be cut is changed by controlling the duty. However, when changing the heat input, it goes without saying that it is sufficient to control not only the duty but also at least one of the laser output and the output frequency.

Next, the configuration of the control device 29 in the laser cutting device according to this embodiment will be explained. This control device 29 includes a calculation unit 29a, a cutting condition storage unit 29b that stores cutting conditions including a cutting speed and laser conditions that correspond to the material of the material to be cut A, a cutting speed that corresponds to the plate thickness in advance, and a cutting condition storage unit 29b that stores cutting conditions including a cutting speed and laser conditions. The cutting speed is gradually decreased from the preset cutting speed as the corner is approached, and when the corner is reached, the cutting speed is the lowest, and after passing the corner, the cutting speed is reduced to the preset cutting speed. a cutting speed control unit 29c that controls the laser output to gradually increase the cutting speed to the corner portion to be cut, and cuts the material as the cutting speed gradually decreases from the preset cutting speed as the cutting speed approaches the corner to be cut; At the corner, the output is gradually decreased from the preset output, and before reaching the corner, the output is gradually increased from the gradually decreased output, and when the corner is reached, the output is lower than the preset output, and when the corner is reached, the output is lower than the preset output. a laser condition control unit 29d that controls the laser to gradually decrease the output after passing through the laser beam, and then gradually increase the output to the preset output; and a primary storage unit that temporarily stores input from the input device 30. 29e.

In the laser cutting device having the control device 29 configured as described above, when cutting the material to be cut A, information such as the cutting conditions including the thickness of the target material to be cut A and the shape 1 to be cut is transmitted. When input is input from the input device 30 and cutting is started, the cutting line 3 of the figure 1 is cut according to the input conditions.

Then, when the laser torch 25 approaches the corner 2 and reaches the position S3, as shown in FIG. proceed. During this cutting process, the cutting speed V gradually decreases from position S3 toward position S2, and after passing through position S2, gradually increases toward position S4. This process of gradually decreasing and increasing the cutting speed V is the same as in conventional laser cutting.

The laser torch 25 performs a heat input P3 on the cutting line 3 of the figure 1, and as shown in FIG. 2, after reaching the position S3, the laser torch 25 gradually decreases from the heat input P3 to the heat input P03 toward the position S03. Then, when reaching position S03, heat input P03 is reached, and then gradually increases to heat input P2 toward position S2, becomes heat input P2 at position S2, and after passing position 2, toward position S04 until heat input P04. Decrease gradually. Furthermore, the heat input P04 when reaching the position S04 gradually increases toward the position S4, and after reaching the heat input P4 at the position S4, cutting along the cutting line 4 is continued at the preset heat input P4.

In this way, when the laser torch 25 passes the position S2 corresponding to the corner 2, the heat input P is gradually increased, thereby increasing the cutting ability for the portion of the workpiece A where the cutting delay occurs on the back side. This will improve the results. As a result, cutting progresses on the portion where the cutting delay occurs on the upstream side in the cutting progress direction, making it possible to reduce or eliminate the cutting delay. Therefore, it is possible to reduce the difference in roundness between the front side and the back side of the corner 2 of the cut figure 1, and configure the corner 2 from the front side to the back side as a substantially vertical line.

With the laser cutting method according to the present invention, corners can be cut well regardless of the thickness of the material to be cut, and it is advantageous for use in precision cutting of the material to be cut.

A Material to be cut S, S3, S03, S2, S04, S4 Position V, V3, V03, V2, V04, V4 Cutting speed P, P3, P03, P2, P04, P4 Heat input t1, t2 Time 1 Figure 2 Corner Parts 3 and 4 Cutting line 20 Rail 21 Dolly 22 Traveling motor 23 Traversing carriage 24 Traversing motor 25 Laser torch 26 Laser oscillator 28 Operation panel 29 Control device 29a Computing section 29b Cutting condition storage section 29c Cutting speed control section 29d Laser condition control section 29e Primary Storage unit 30 Input device

Claims (6)

A laser cutting method for cutting a corner to be cut when cutting a material to be cut along a preset scheduled cutting line by irradiating a laser beam to the material, the method comprising:
As the corner to be cut is approached, the cutting speed is gradually decreased from the preset speed when cutting the material to be cut, and the heat input is reduced to the preset speed when cutting the material to be cut. gradually decrease the
Before reaching the corner, the cutting speed is gradually decreased while the heat input is gradually increased relative to the gradually decreased heat input;
when the corner is reached, the cutting speed is set to the lowest and the gradually increased heat input is lower than the preset heat input;
After passing the corner, the cutting speed is gradually increased and the heat input is gradually decreased from the gradually increased heat input,
Subsequently, the cutting speed is gradually increased to the preset speed and the heat input is gradually increased to the preset heat input, and as the cutting speed reaches the preset speed, the heat input is increased to the preset speed. A laser cutting method characterized in that the heat input is gradually increased to a certain temperature. 2. The laser cutting method according to claim 1, wherein the heat input is set in accordance with a cutting speed. 3. The set value of the heat input to the cutting part corresponding to the cutting speed is set at least one of a duty of a laser beam, a laser output, or a frequency control condition. Laser cutting method. A laser cutting device that cuts a corner to be cut when cutting a material to be cut along a preset scheduled cutting line by irradiating a laser beam to the material,
a cutting condition storage unit that stores in advance cutting conditions including cutting speed and laser conditions corresponding to the material and thickness of the material to be cut;
The cutting speed is gradually decreased from the preset cutting speed as the corner to be cut is approached, and when the corner is reached, the cutting speed is the lowest, and after passing the corner, the cutting speed is reduced to the preset cutting speed. a cutting speed control unit that controls the cutting speed to gradually increase the cutting speed to a set cutting speed;
The heat input by the laser beam is gradually decreased from the preset heat input when cutting the material to be cut as the cutting speed gradually decreases as the cutting speed approaches the corner to be cut. The heat input is gradually increased from the gradually decreased heat input before reaching the corner, the heat input is lower than the preset heat input when reaching the corner, and the gradually increased heat input is made after passing the corner. a laser condition control unit that controls the heat input to gradually decrease the heat input and then gradually increase the heat input to the preset heat input;
A laser cutting device characterized by having: 5. The laser cutting device according to claim 4, wherein the laser conditions are set in accordance with a cutting speed. 6. The laser cutting device according to claim 4, wherein the laser condition setting value corresponding to the cutting speed sets at least one of a laser beam duty, a laser output, or a frequency control condition. .

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