JP2022001375A - Laser cutting method - Google Patents

Abstract

To provide a laser cutting method that can reduce delay in cutting a backside of a material to be cut, when cutting a corner part of a graphic from the material to be cut.SOLUTION: As approaching a corner part 2 to be cut, a cutting speed V is gradually made lower than a preset speed when cutting a material A to be cut and heat input P is gradually made smaller than preset heat input. Before reaching the corner part 2, the heat input is gradually made more than the gradually lowered heat input while keeping on gradually lowering the cutting speed, and when reaching the corner part 2, the cutting speed is made lowered to the lowest speed and the gradually increased input heat is made smaller than the preset heat input. After passing on the corner part 2, the cutting speed is gradually increased and the heat input is gradually made smaller than the gradually increased heat input, the cutting speed is gradually increased up to the preset speed continuously, and the heat input is gradually increased up to the preset heat input. As the cutting speed reaches the preset speed, the heat input is gradually increased up to the preset heat input.SELECTED DRAWING: Figure 2

Description

The present invention relates to a corner laser cutting method capable of rationally cutting a corner portion when a figure including the corner portion is laser-cut by irradiating a laser beam toward the material to be cut.

A laser cutting method is widely adopted in which a laser beam is irradiated toward a material to be cut and an assist gas is injected along with the laser light, or a shield gas is injected along the assist gas to cut the material to be cut. Has been done.

In this laser cutting, a laser beam is irradiated from a nozzle attached to the laser torch toward the upper surface of the material to be cut and an assist gas is ejected, and the melt generated by the irradiated laser beam and the ejected assist gas is discharged on the back surface side. It is done by eliminating the laser and forming a groove. Then, by moving the laser torch along a preset scheduled cutting line, a continuous cutting groove is formed along the scheduled cutting line to perform the desired cutting.

In such cutting, a time lag occurs between the reaction on the front surface side and the reaction on the back surface side of the material to be cut, and the cut surface formed on the material to be cut is directed backward from the direction of progress of cutting. A diagonal line (drag line) is formed.

Even when the diagonal drag line as described above is formed, it is not a big problem if the target planned 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, the drag line delay will be expressed on the back side, so it will not be cut at the desired angle. The problem arises.

Therefore, when cutting the corner portion, how to eliminate the delay on the back surface side with respect to the front surface side has been raised as an issue. In order to solve this problem, after cutting by passing through the corner while cutting one side constituting the corner, the laser torch is moved to move the laser torch from the extension line of the other side of the corner or the corner. Therefore, a cutting method for cutting has been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-066144

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

When cutting the corners, the cutting speed is reduced to continuously cut, or the corners are stopped once to cut. In this case, if the heat input when cutting the corner portion is left as the heat input when cutting the side portion, the heat input at the corner portion may become excessive and self-burning may occur. Therefore, the heat input is also reduced as the cutting speed is reduced, but in this case, there is a problem that the cutting delay on the back surface side cannot be eliminated.

An object of the present invention is to provide a laser cutting method capable of reducing a cutting delay on the back surface side when cutting a corner portion of a figure to be cut from a material to be cut, and a laser cutting device.

A typical corner laser cutting method according to the present invention is a laser cutting method for cutting a corner to be cut when the material to be cut is irradiated with a laser beam to cut along a preset scheduled cutting line. Therefore, the cutting speed is gradually reduced from the preset speed when cutting the material to be cut as it approaches the corner to be cut, and the heat input is set in advance when cutting the material to be cut. It is gradually reduced from the heat input, and the cutting speed is gradually reduced before reaching the corner, and the heat input is gradually increased from the gradually reduced heat input, and the cutting speed is set to the lowest when the corner is reached. At the same time, the gradually increased heat input is set to be lower than the preset heat input, and after passing through the corner, the cutting speed is gradually increased and the heat input is gradually reduced from the gradually increased heat input, and then continued. The cutting speed is gradually increased to the preset speed and the heat input is gradually increased to the preset heat input, and the heat input is preset as the cutting speed reaches the preset speed. It is characterized by gradually increasing the amount of heat input.

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 the material to be cut is irradiated with laser light to cut along a preset scheduled cutting line. The cutting condition storage unit that stores the cutting conditions including the cutting speed and laser conditions corresponding to the material of the material to be cut and the plate thickness in advance, and the cutting speed as the cutting speed approaches the corner portion to be cut. Cutting speed control that controls the cutting speed to be gradually reduced from the preset cutting speed to the lowest when the corner is reached, and after passing through the corner, the cutting speed is gradually increased to the preset cutting speed. Pre-set heat input when cutting the material to be cut due to the gradual decrease of the preset cutting speed of the cutting speed associated with approaching the portion and the corner portion to be cut by the heat input by the laser beam. After gradually decreasing the heat input, the heat input is gradually increased from the gradually reduced heat input before reaching the corner portion, and when the corner portion is reached, the heat input is lower than the preset heat input, and after passing through the corner portion, the heat input is set to be lower than the preset heat input. A laser condition control unit that controls to gradually increase the heat input to the preset heat input after the heat is gradually reduced from the gradually increased heat input.
It has.

In the laser cutting method according to the present invention, it is possible to reduce the delay on the back surface side of the material to be cut when cutting the corner portion. That is, the cutting speed is gradually reduced as the target cut material is cut with the preset speed approaching the corner, and when the corner is reached, the cutting speed is set to the lowest and the cutting speed is passed through the corner. After that, the speed is gradually increased to a preset speed. Then, the heat input is gradually reduced with the gradual decrease of the cutting speed, gradually increased before reaching the corner, reaches the corner, passes through the corner, is gradually reduced again, and then is gradually increased. Therefore, when reaching and passing through the corner, the heat input is not the lowest, even though the cutting speed is the lowest.

When passing through the corner portion in this way, the heat input is higher than the cutting speed. Therefore, the relative cutting ability is high. Therefore, the heat input to the back surface side of the material to be cut becomes high, and the delay in cutting generated on the back surface side can be reduced or eliminated.

Further, in the laser cutting apparatus according to the present invention, it is possible to smoothly cut a corner portion existing when cutting a preset scheduled cutting line.

It is a figure which schematically explains the laser cutting method which concerns on this invention. It is a figure explaining the change of the cutting speed and the change of heat input at the time of carrying out the laser cutting method which concerns on this Example. It is a photograph comparing the back surface of the material to be cut cut by this example and the back surface of the material to be cut cut by the conventional laser cutting method. It is a figure which schematically explains the laser cutting apparatus which concerns on this Example. It is a figure which schematically explains the structure of the control device which comprises the laser cutting device.

Hereinafter, the laser cutting method and the laser cutting device according to the present invention will be described with reference to FIGS. 1 and 4. The laser cutting method according to the present invention is a method for cutting the corner portion 2 included in the figure 1 to be cut set in the material A to be cut shown in FIG. In particular, by reducing or eliminating the cutting delay on the back surface side of the material A to be cut in the corner portion 2 with respect to the front surface side, the corner portion 2 is cut so as to be a substantially straight line from the front surface side to the back surface side. Is.

The laser cutting device according to the present invention has a carriage 21 traveling along the rail 20 and a traverse carriage 23 traveling on the carriage 21 in a direction orthogonal to the rail 20. The bogie 21 is driven by the traveling motor 22, and the traversing carriage 23 is driven by the traversing motor 24. A laser torch 25 is arranged so as to be able to move up and down on the transverse carriage 23, and a laser oscillator 26 is connected to the laser torch 25. An operation panel 28 is arranged on the carriage 21, and the operation panel 28 comprises a control device 29 for controlling a traveling motor 22, a transverse motor 24, and a laser oscillator 26.

By controlling the traveling motor 22, the transverse 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 performed. Cutting is performed by running along. Then, in this process, the corner portion 2 is cut.

When cutting the corner portion 2, it is not limited whether the cutting proceeds in the order of the cutting line 3 to the corner portion 2 to the cutting line 4 or the cutting proceeds in the order of the cutting line 4 to the corner portion 2 to the cutting line 3. Further, the cutting speed with respect to the material to be cut A is set mainly according to the plate thickness, although it varies depending on conditions such as the plate thickness, material and surface condition of the material A to be cut.

As shown in FIG. 2, since the cutting direction changes at the corner portion 2, the traveling speed (cutting speed) of the laser nozzle 25 is set to be the slowest when the corner portion 2 is reached. However, the traveling of the laser nozzle 25 is not stopped, 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 the irradiation of the laser beam to the material A to be cut in accordance with the change in the cutting speed, the edge formed by the surface formed by the cutting line 3 forming the corner portion 2 and the surface formed by the cutting line 4 can be formed. It can be configured substantially vertically from the front surface side to the back surface side. That is, with respect to the corner portion 2, the distance from the corner portion 2 or the time to reach the corner portion 2 is located on the upstream side (cutting line 3 side) and the downstream side (cutting line 4 side) in the cutting traveling direction, respectively. The time of separation from the corner portion 2 is set, and the cutting speed and heat input at each set point are controlled in correspondence with each other.

As shown in FIG. 2, a position S3 at which a plurality of positions S start to change the cutting direction from the cutting line 3 toward the corner 2 with the corner 2 as a reference, a separation distance from the corner 2, or the corner 2 It is set as the position S03 and the position S04 set at the time to reach the position S4, and the position S4 where the change of the cutting direction is completed from the corner portion 2 toward the cutting line 4. The distance between the positions S is not uniquely set, but is set according to the plate thickness of the material A to be cut, heat input conditions, and the like.

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

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

In this embodiment, when the plate thickness of the material A to be cut is 12 mm, the speeds V3 and V4 are set to approximately 1100 mm / min, the speed V2 is set to approximately 650 mm / min, and the speeds V03 and V04 are set to approximately 850 mm / min. Has been done. When the plate thickness of the material A to be cut is 19 mm, the speeds V3 and V4 are set to about 900 mm / min, the speed V2 is set to about 550 mm / min, and the speeds V03 and V04 are set to about 700 mm / min. .. Further, when the plate thickness of the material A to be cut is 25 mm, the speeds V3 and V4 are set to about 650 mm / min, the speed V2 is set to about 450 mm / min, and the speeds V03 and V04 are set to about 500 mm / min. ..

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

In this embodiment, the heat input P due to the irradiation of the laser beam is changed by controlling the duty. When the plate thickness of the material A to be cut is 12 mm, the heat input 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 input P03 and P04 are set to a duty of approximately 35%. There is. When the plate thickness of the material A to be cut is 19 mm, the heat input 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 input P03 and P04 are set to a duty of approximately 53%. Has been done. Further, when the plate thickness of the material A to be cut is 25 mm, the heat input 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 input P03 and P04 are set to a duty of approximately 49%, respectively. Has been done.

When the material A to be cut of each plate thickness was cut according to the above-mentioned set values and the roundness on the front surface side and the roundness on the back surface side at the corner portion 2 were compared, the roundness on the back surface side was slightly larger, but 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 surface side was approximately 700 μm, whereas the roundness on the back surface side was approximately 800 μm. As described above, it is sufficiently practical that the thickness is 19 mm and the difference in roundness between the front surface side and the back surface side is 100 μm.

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

In the above-described embodiment, the change in heat input to the material A to be cut is controlled by controlling the duty. However, when changing the heat input, it is natural that not only the duty but also at least one of the laser output and the output frequency may be controlled.

Next, the configuration of the control device 29 in the laser cutting device according to this embodiment will be described. The control device 29 cuts the calculation unit 29a, the cutting condition storage unit 29b that stores the cutting conditions including the material of the material A to be cut, the cutting speed corresponding to the plate thickness in advance, and the laser conditions, and the cutting speed. It is gradually reduced from the preset cutting speed as it approaches the corner to be the lowest when it reaches the corner, and after passing through the corner, the cutting speed is set to the preset cutting speed. The cutting speed control unit 29c that controls to gradually increase the cutting speed, and the cutting material to be cut are cut as the laser output gradually decreases in the cutting speed as the cutting speed approaches the corner to be cut. At the time, the output is gradually reduced from the preset output, gradually increased from the gradually reduced output before reaching the corner, and when the corner is reached, the output is lower than the preset output, and the corner is set. After passing through, the laser condition control unit 29d that controls to gradually decrease the output from the gradually increased output and then gradually increase the output to the preset output, and the primary storage unit for primary storage input from the input device 30. It is configured to have 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 cutting conditions including the plate thickness of the target material A to be cut and the figure 1 to be cut is input. 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 portion 2 and reaches the position S3, as shown in FIG. 2, the rotation of the traveling motor 22 traversing motor 24 is controlled and the laser oscillator 26 is controlled to cut the corner portion 2. proceed. In the process of this cutting, the cutting speed V gradually decreases from the position S3 toward the position S2, and gradually increases toward the position S4 after passing through the position S2. The process of gradually decreasing and increasing the cutting speed V is the same as that of conventional laser cutting.

The laser torch 25 is applied to the cutting line 3 of the figure 1 by the heat input P3, and as shown in FIG. 2, after reaching the position S3, the heat is gradually reduced from the heat input P3 to the heat input P03 toward the position S03. Then, when it reaches the position S03, it reaches the heat input P03, then gradually increases to the heat input P2 toward the position S2, becomes the heat input P2 at the position S2, passes through the position 2, and then reaches the heat input P04 toward the position S04. Gradually decrease. Further, the heat input P04 when reaching the position S04 gradually increases toward the position S4, reaches the heat input P4 at the position S4, and then continues cutting with respect to the cutting line 4 at the preset heat input P4.

In this way, when the laser torch 25 passes through the position S2 corresponding to the corner portion 2, the heat input P is gradually increased, so that the cutting ability for the cut delay portion generated on the back surface side of the material A to be cut is increased. It will be improved. As a result, cutting proceeds with respect to the cutting delay portion generated on the upstream side in the cutting progress direction, and it becomes possible to reduce or eliminate the cutting delay. Therefore, it is possible to reduce the difference in roundness between the front surface side and the back surface side of the corner portion 2 of the cut figure 1 and to configure the corner portion 2 from the front surface side to the back surface side as a substantially vertical line.

In the laser cutting method according to the present invention, it is possible to cut corners satisfactorily regardless of the thickness of the material to be cut, which is advantageous when the material to be cut is precisely 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 corners Part 3, 4 Cutting line 20 Rail 21 Carriage 22 Traveling motor 23 Traverse carriage 24 Traverse motor 25 Laser torch 26 Laser oscillator 28 Operation panel 29 Control device 29a Calculation unit 29b Cutting condition storage unit 29c Cutting speed control unit 29d Laser condition control unit 29e Primary Storage unit 30 Input device

Claims (6)

It is a laser cutting method that cuts the corners to be cut when the material to be cut is irradiated with laser light and cut along a preset cut line.
As it approaches the corner to be cut, the cutting speed is gradually reduced from the preset speed when cutting the material to be cut, and the heat input is preset when the material to be cut is cut. Gradually decrease,
Prior to reaching the corner, the cutting rate was continuously reduced while the heat input was gradually increased from the gradually reduced heat input.
When the corner is reached, the cutting speed is set to the lowest speed, and the gradually increased heat input is set to be lower than the preset heat input.
After passing through the corners, the cutting speed is gradually increased and the heat input is gradually reduced 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 the heat input is preset as the cutting speed reaches the preset speed. A laser cutting method characterized by gradually increasing the amount of heat input. The laser cutting method according to claim 1, wherein the heat input is set according to the cutting speed. The first or second aspect of the present invention, wherein the set value of the heat input to the cutting portion corresponding to the cutting speed is set to at least one of the control conditions of the duty, the laser output, or the frequency of the laser beam. Laser cutting method. A laser cutting device that cuts corners to be cut when the material to be cut is irradiated with laser light and cut along a preset scheduled cutting line.
A cutting condition storage unit that stores cutting conditions including cutting speed and laser conditions corresponding to the material of the material to be cut and the plate thickness in advance.
The cutting speed is gradually reduced from the preset cutting speed as it approaches the corner to be cut, and is set to the lowest when reaching the corner, and after passing through the corner, the cutting speed is set to the preset cutting speed. A cutting speed control unit that controls to gradually increase to the set cutting speed,
The heat input by the laser beam is gradually reduced from the preset heat input when cutting the material to be cut due to the gradual decrease of the preset cutting speed 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, and when the corner is reached, the heat input is lower than the preset heat input, and after passing through the corner, the heat is gradually increased. A laser condition control unit that controls the heat input to be gradually increased and then gradually increased to the preset heat input.
A laser cutting device characterized by having. The laser cutting apparatus according to claim 4, wherein the laser conditions are set according to the cutting speed. The laser cutting apparatus according to claim 4 or 5, wherein the set value of the laser condition corresponding to the cutting speed is set to at least one of the control conditions of the duty or the laser output or the frequency of the laser light. ..

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