Cutting machine and cutting method

Abstract

This cutting machine comprises: an emission part capable of cutting a material being processed by emitting a laser and an assist gas onto the material being processed; a switching part capable of supplying a first gas and a second gas having a nitrogen concentration higher than that of the first gas to the emission part as the assist gas, and capable of switching the assist gas supplied to the emission part; and a control unit that controls the switching part, thereby changing the assist gas supplied to the emission part by the switching part. The emission part can change a cutting speed for cutting the material being processed to a first speed or a second speed lower than the first speed. The control unit changes the assist gas supplied to the emission part on the basis of the cutting speed.

Description

Cutting machine and cutting method

[0001] This application claims priority to Japanese Patent Application No. 2024-012891, filed on January 31, 2024, the contents of which are incorporated herein by reference.

[0002] Conventionally, there are laser cutting machines that use laser to cut workpieces such as steel plates, etc. Laser cutting machines are classified into two types, for example, a bed type and a gantry type.

[0003] A bed-type laser cutting machine is a laser cutting machine in which the cutting head moves over the workpiece placed on a table inside the machine body cover to perform laser cutting. Bed-type laser cutting machines are small and lightweight. Bed-type laser cutting machines are also called table-type laser cutting machines.

[0004] A gantry-type laser cutting machine is a laser cutting machine in which the gate-shaped cutting machine body travels on rails to cut the workpiece. Gantry-type laser cutting machines are large and heavy. Gantry-type laser cutting machines are also called gate-type laser cutting machines.

[0005] Traditionally, oxygen gas has often been used as an assist gas in laser cutting of materials such as mild steel. In recent years, as laser power has become higher, laser cutting using nitrogen gas, which does not rely on oxidation reactions, has become more common in order to achieve higher speeds.

[0006] In laser cutting using nitrogen gas as an assist gas, dross adheres to the backside of the cut surface, necessitating post-processing such as grinding after laser cutting. One laser cutting method that reduces dross adhesion is laser cutting that uses a mixed gas, in which nitrogen gas is mixed with a small amount of oxygen gas or compressed air, as an assist gas (for example, Patent Document 1).

[0007] When laser cutting using mixed gases, the amount of dross that adheres is less than when laser cutting using nitrogen gas in the high-speed range, but the amount of dross that adheres tends to be more than when laser cutting using nitrogen gas in the low-speed range.

[0008] When cutting fine shapes such as small circles, it may be necessary to reduce the cutting speed to ensure cutting accuracy, and using a mixed gas may increase the amount of dross that adheres.

[0009] Bed-type laser cutting machines do not require a significant reduction in cutting speed even when cutting fine shapes, and can cut a variety of shapes using the same gas mixture.

[0010] Japanese Patent Application Publication No. 2001-353588

[0011] However, in the case of a gantry-type laser cutting machine, the speed changes more significantly depending on the cutting shape than in the case of a bed-type laser cutting machine, so when using a mixed gas to suppress the amount of dross, the cutting shape may be limited.

[0012] In view of the above circumstances, an object of the present disclosure is to provide a cutting machine and a cutting method that suppress the adhesion of dross regardless of the cut shape of the workpiece.

[0013] A cutting machine according to a first aspect of the present disclosure comprises an injection unit capable of injecting a laser and an assist gas onto a workpiece to cut the workpiece, a switching unit capable of supplying a first gas and a second gas having a higher nitrogen concentration than the first gas as the assist gas to the injection unit and capable of switching the assist gas supplied to the injection unit, and a control unit capable of changing the assist gas supplied to the injection unit by controlling the switching unit, wherein the injection unit is capable of changing the cutting speed at which the workpiece is cut to a first speed or a second speed slower than the first speed, and the control unit changes the assist gas supplied to the injection unit based on the cutting speed.

[0014] A cutting method according to a second aspect of the present disclosure is a cutting method for cutting a workpiece by injecting a laser and an assist gas into the workpiece, and based on the cutting speed at which the workpiece is cut, the assist gas injected into the workpiece is switched to a first gas or a second gas having a higher nitrogen concentration than the first gas.

[0015] A cutting machine according to a third aspect of the present disclosure comprises an injection section capable of injecting a laser and an assist gas onto a workpiece to cut the workpiece, a switching section capable of supplying a first gas and a second gas having a higher nitrogen concentration than the first gas as the assist gas to the injection section and capable of switching the assist gas supplied to the injection section, and a control section capable of changing the assist gas supplied to the injection section by the switching section by controlling the switching section, wherein the control section changes the assist gas supplied to the injection section based on the cutting area across which the injection section cuts the workpiece.

[0016] A cutting method according to a fourth aspect of the present disclosure is a cutting method for cutting a workpiece by injecting a laser and an assist gas into the workpiece, and switches the assist gas injected into the workpiece to a first gas or a second gas having a higher nitrogen concentration than the first gas based on the cutting area of ​​the workpiece.

[0017] According to the cutting machine and cutting method of the present disclosure, it is possible to provide a cutting machine and cutting method that suppresses the adhesion of dross regardless of the cut shape of the workpiece.

[0018] FIG. 1 is a perspective view schematically showing a cutting machine according to an embodiment of the present disclosure; FIG. 2 is a block diagram schematically showing a method of supplying an assist gas in the cutting machine; FIG. 3 is a photograph showing the back surface of a workpiece on which peripheral cutting has been performed using a first gas; FIG. 4 is a photograph showing the back surface of a workpiece on which peripheral cutting has been performed using a second gas; FIG. 5 is a photograph showing the back surface of a workpiece on which small hole cutting has been performed using a second gas; and FIG. 6 is a photograph showing the back surface of a workpiece on which small hole cutting has been performed using a first gas.

[0019] First Embodiment Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings.

[0020] Fig. 1 is a perspective view schematically illustrating a cutting machine 1 according to an embodiment of the present disclosure. Fig. 2 is a block diagram schematically illustrating a method of supplying assist gas in the cutting machine 1.

[0021] The cutting machine 1 includes a surface plate 10, a cutting machine main body 20, an operation deck 30, an operation unit 40, a control unit 50, and a switching unit 60. The cutting machine 1 is a device that cuts a workpiece such as a steel plate placed on the surface plate 10, and is a gate-type mobile (gantry-type) laser cutting machine in which the gate-type cutting machine main body can travel on rails.

[0022] In this embodiment, the vertical direction of the cutting machine 1 is defined as the "up-down direction Z," the vertically upward direction as the "upward Z1" in the vertical direction Z, and the vertically downward direction as the "downward Z2" in the vertical direction Z. Furthermore, among the horizontal directions perpendicular to the vertical direction Z, the direction in which the cutting machine 1 travels is defined as the "traveling direction X," the direction in which the cutting machine 1 moves forward is defined as the "forward X1" in the traveling direction X, and the direction opposite to the forward X1 in which the cutting machine 1 moves backward is defined as the "rearward X2" in the traveling direction X. Furthermore, the direction perpendicular to the vertical direction Z and the traveling direction X is defined as the "width direction Y," with one side in the width direction Y being defined as the "leftward Y1" and the other side being defined as the "rightward Y2" in the width direction Y.

[0023] The surface plate 10 is a platform on which a workpiece to be cut by the cutting machine 1 can be placed on its surface in the upper direction Z1, and is formed in a rectangular shape when viewed from above Z1. The surface plate 10 is placed on the ground or floor. The workpiece placed on the surface plate 10 is, for example, a steel plate made of mild steel.

[0024] The cutting machine body 20 is provided above the surface plate 10 on a Z1 side and is configured to be able to travel on a pair of rails R arranged along the traveling direction X. As shown in FIG. 1 , the rails R are provided on the left side Y1 and the right side Y2 of the surface plate 10.

[0025] The cutting machine main body 20 includes a carriage 21 , a drive unit 22 , a machine body cover unit 25 , a cutting head (ejection unit) 27 , an area sensor 28 , and an alarm unit 29 .

[0026] The carriage 21 is a gate-shaped frame that is movable in the traveling direction X above the surface plate 10 Z1. The cutting machine main body 20 moves in the traveling direction X as the carriage 21 travels on the rails R.

[0027] The drive unit 22 includes a wheel (not shown) mounted on the rail R and rotatable relative to the rail R, and an electric motor (not shown) such as an electric motor that can rotate the wheel around an axis extending in the width direction Y as the center of rotation.

[0028] The drive unit 22 rotates the wheels using an electric motor to move the carriage 21, thereby moving the cutting machine main body 20 in the traveling direction X. The cutting machine main body 20 is provided with a pair of drive units 22. The pair of drive units 22 are provided corresponding to a pair of rails R provided on the left side Y1 and the right side Y2 of the surface plate 10.

[0029] The machine body cover 25 is provided above the carriage 21 in the Z1 direction, and is a member that covers the cutting space in which the workpiece placed on the surface plate 10 is cut. By covering the cutting space with the machine body cover 25, the inside (cutting space) of the cutting machine 1 can be separated from the outside, improving safety during cutting work.

[0030] The machine body cover section 25 may be provided so as to be able to open and close the cutting space. Alternatively, the machine body cover section 25 may be configured such that a plurality of machine body cover sections 25 are arranged side by side in the width direction Y and each of the plurality of machine body cover sections 25 can be opened and closed independently.

[0031] The cutting head (injection unit) 27 is a cutting device capable of cutting a workpiece placed on the surface plate 10. The cutting head 27 is provided in the above-mentioned cutting space covered by the machine body cover unit 25.

[0032] The cutting head 27 is provided so as to be movable in the width direction Y. For example, the cutting head 27 is provided on a rail extending in the width direction Y, and is configured so as to be movable in the width direction Y along the rail. The cutting head 27 is also provided so as to be movable in the up-down direction Z.

[0033] A cutting torch (not shown) is provided at the lower end Z2 of the cutting head 27. The cutting head 27 laser-cuts the workpiece by emitting assist gas and a laser beam from the cutting torch onto the workpiece. The laser emitted from the cutting head 27 may be, for example, a fiber laser with an output of 1 kW or more.

[0034] The cutting head 27 is movable in the traveling direction X relative to the workpiece as the cutting machine body 20 travels in the traveling direction X on the rails R. As described above, the cutting head 27 is provided on the cutting machine body 20 so as to be movable in the width direction Y and the up-down direction Z. Therefore, the cutting head 27 is movable in the up-down direction Z, the width direction Y and the traveling direction X relative to the workpiece, and moves in any direction to cut the workpiece.

[0035] 1, the area sensor 28 is provided in the front X1 of the machine body cover part 25. The cutting machine body 20 includes a pair of area sensors 28 provided on the left Y1 and right Y2 of the machine body cover part 25.

[0036] The area sensors 28 are sensors that can detect an object that obstructs an area sandwiched between the pair of area sensors 28. The area sensors 28 are provided in the cutting machine 1 as a safety device.

[0037] The alarm unit 29 is a warning light that protrudes upward Z1 from the cutting machine body 20. The alarm unit 29 is an alarm device that notifies of danger by turning on the warning light. For example, the control unit 50, which will be described later, acquires the detection result of the area sensor 28, and controls the alarm unit 29 based on the acquired detection result to turn on the warning light.

[0038] The operation deck 30 is provided on the left side Y1 of the cutting machine body 20 and is a work deck on which an operator can get on. The operation deck 30 is equipped with an opening / closing door that can open and close the cutting space. An operator can perform maintenance on the cutting head 27 by getting on the operation deck 30 and opening the opening / closing door. In addition, the safety of the operator can be ensured by closing the opening / closing door when cutting the workpiece.

[0039] The operation unit 40 is provided above the operation deck 30 in the area Z1, and is an input device that allows an operator to input operations to the cutting machine 1. The operation unit 40 includes, for example, a display device such as a display that can display various information, and buttons and the like that allow an operator to input operations to the cutting machine 1. The operation unit 40 may also include a touch panel that allows an operator to input operations to the cutting machine 1.

[0040] The control unit 50 is a control device capable of controlling a part or the whole of the cutting machine 1. The control unit 50 is provided at the rear X2 of the cutting machine main body 20. The control unit 50 controls the cutting machine 1 based on, for example, an operation input to the operation unit 40, and causes the cutting head 27 to cut the workpiece placed on the surface plate 10.

[0041] The control unit 50 is a programmable device (computer) equipped with, for example, a processor, a memory, a storage unit, etc. Each function of the control unit 50 is realized by one or more processors, such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), executing a program stored in a program memory. However, all or part of these functions may be realized by hardware (e.g., circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a PLD (Programmable Logic Device). Furthermore, all or part of the above functions may be realized by a combination of software and hardware. The storage unit is realized by, for example, a flash memory, an EEPROM (Electrically Erasable Programmable Read-Only Memory), a ROM (Read-Only Memory), or a RAM (Random Access Memory).

[0042] The switching unit 60 is a switching device that can switch the assist gas injected from the cutting head 27. The switching unit 60 is, for example, a three-way valve that can open and close the flow path of the assist gas. The control unit 50 controls the switching unit 60 and causes the switching unit 60 to switch the assist gas.

[0043] 2, a first gas GA and a second gas GB flow into the switching unit 60. The first gas GA and the second gas GB are assist gases used when the cutting machine 1 cuts the workpiece.

[0044] The control unit 50 opens and closes the flow path in the switching unit 60 so that either the first gas GA or the second gas GB flows into the cutting head 27 , thereby changing the assist gas flowing into the cutting head 27 .

[0045] The first gas GA is a mixed gas obtained by mixing nitrogen gas with a gas other than nitrogen gas. In the first gas GA, the gas mixed with the nitrogen gas may be oxygen gas or air. Alternatively, an inert gas such as helium gas or argon gas may be used instead of nitrogen gas. The oxygen concentration of the first gas GA is preferably 10% or less.

[0046] The second gas GB is an assist gas having a higher nitrogen concentration than the first gas GA. The second gas GB is, for example, a high-purity nitrogen gas having a nitrogen purity of 99.999% or more.

[0047] In the cutting machine 1, the first gas GA and the second gas GB are, for example, at a pressure of 0.5 MPa or more and a flow rate of 50 m ３ / h or more.

[0048] The control unit 50 switches the assist gas flowing into the cutting head 27 from the switching unit 60 based on the cutting speed of the cutting head 27. For example, the control unit 50 switches the assist gas based on the cutting speed input by the operator to the operation unit 40.

[0049] Generally, the cutting speed when cutting a workpiece with a laser cutting machine is determined based on the cut shape.

[0050] In the gantry-type cutting machine 1, when performing peripheral cutting, which cuts the vicinity of the outer periphery of the workpiece, it is desirable to set the cutting speed of the cutting head 27 to a high speed range. Also, when cutting a fine shape such as a small hole, it is desirable to set the cutting speed of the cutting head 27 to a low speed range.

[0051] In the following description, the cutting speed when the cutting machine 1 cuts the workpiece in the high-speed range is referred to as a first speed, and the cutting speed when the cutting machine 1 cuts the workpiece in the low-speed range is referred to as a second speed.

[0052] The first speed is a cutting speed faster than the second speed and is used primarily for peripheral cutting of the workpiece. When peripheral cutting of the workpiece is performed, cutting at the first speed can shorten the cutting time.

[0053] The second speed is a cutting speed that is mainly used for cutting fine shapes such as small holes. When cutting fine shapes such as small holes in a workpiece, cutting accuracy can be ensured by cutting at the second speed, which is slower than the first speed.

[0054] Here, the first speed and the second speed are speed regions distinguished based on a predetermined value and have a predetermined width. The first speed, which is the high-speed region, is a cutting speed equal to or greater than the predetermined value. The second speed, which is the low-speed region, is a cutting speed less than the predetermined value. For example, the first speed indicates a cutting speed of 3000 mm / min or greater. For example, the second speed indicates a cutting speed less than 3000 mm / min.

[0055] When the cutting speed is the first speed, the control unit 50 controls the switching unit 60 to eject the first gas GA from the cutting head 27 as the assist gas.

[0056] Fig. 3 is a photograph showing the back surface of a workpiece that has been peripherally cut using the first gas GA. That is, Fig. 3 is a photograph showing the back surface of a workpiece that has been cut under the cutting conditions of the first gas GA and the first speed.

[0057] Fig. 4 is a photograph showing the back surface of a workpiece that has been peripherally cut using the second gas GB, i.e., the back surface of the workpiece that has been cut under the cutting conditions of the second gas GB and the first speed.

[0058] The workpiece shown in Figures 3 and 4 is an SS400 material with a plate thickness of 12 mm, and is cut at a cutting speed of 5500 mm / min.

[0059] As shown in Figures 3 and 4, the amount of dross adhering to the back surface of the workpiece shown in Figure 3 is less than the amount of dross adhering to the back surface of the workpiece shown in Figure 4. In other words, when the workpiece is cut at the first speed, the amount of dross adhering to the back surface of the workpiece cut using the first gas GA as the assist gas is less than the amount of dross adhering to the back surface of the workpiece cut using the second gas GB as the assist gas.

[0060] When the cutting speed is the second speed, the control unit 50 controls the switching unit 60 to eject the second gas GB from the cutting head 27 as the assist gas.

[0061] Fig. 5 is a photograph showing the back surface of a workpiece that has been subjected to small hole cutting using the second gas GB, i.e., Fig. 5 is a photograph showing the back surface of a workpiece that has been cut under the cutting conditions of the second gas GB and the second speed.

[0062] Fig. 6 is a photograph showing the back surface of a workpiece that has been subjected to small hole cutting using the first gas GA, i.e., Fig. 6 is a photograph showing the back surface of a workpiece that has been cut under the cutting conditions of the first gas GA and the second speed.

[0063] The workpiece shown in Figures 5 and 6 is an SS400 material with a plate thickness of 12 mm, and is cut at a cutting speed of 1000 mm / min.

[0064] As shown in Figures 5 and 6, the amount of dross adhering to the back surface of the workpiece shown in Figure 5 is less than the amount of dross adhering to the back surface of the workpiece shown in Figure 6. In other words, when the workpiece is cut at the second speed, the amount of dross adhering to the back surface of the workpiece cut using the second gas GB as the assist gas is less than the amount of dross adhering to the back surface of the workpiece cut using the first gas GA as the assist gas.

[0065] When the control unit 50 determines that the cutting speed for cutting the workpiece is a first speed, it switches the flow path within the switching unit 60 so that the first gas GA is injected from the cutting head 27. When the control unit 50 determines that the cutting speed for cutting the workpiece is a second speed, it switches the flow path within the switching unit 60 so that the second gas GB is injected from the cutting head 27.

[0066] A cutting condition database in which cutting speeds and assist gases are associated is stored in the memory of the control unit 50. The control unit 50 refers to the cutting condition database and selects an assist gas based on the cutting speed. The control unit 50 controls the switching unit 60 based on the selected assist gas to change the assist gas injected from the cutting head 27.

[0067] The cutting machine 1 of this embodiment is equipped with an injection section (cutting head) 27 that is capable of injecting a laser and an assist gas onto the workpiece to cut the workpiece, a switching section 60 that is capable of supplying a first gas GA and a second gas GB having a higher nitrogen concentration than the first gas GA as assist gases to the injection section 27 and is capable of switching the assist gas supplied to the injection section 27, and a control section 50 that is capable of changing the assist gas that the switching section 60 supplies to the injection section 27 by controlling the switching section 60.

[0068] The injection unit 27 can change the cutting speed at which the workpiece is cut to a first speed or a second speed slower than the first speed. The control unit 50 changes the assist gas supplied to the injection unit 27 based on the cutting speed.

[0069] For example, when the cutting speed is a first speed, the control unit 50 supplies a first gas GA from the switching unit 60 to the injection unit 27, and when the cutting speed is a second speed, the control unit 50 supplies a second gas GB from the switching unit 60 to the injection unit 27.

[0070] As a result, even when the cutting speed needs to be changed based on the cut shape of the workpiece, a cutting machine 1 and cutting method can be provided that suppresses dross adhesion regardless of the cut shape of the workpiece.

[0071] Second Embodiment A cutting machine 1A according to a second embodiment of the present disclosure will be described. In the following description, components common to those already described will be assigned the same reference numerals and redundant description will be omitted.

[0072] The cutting machine 1A includes a surface plate 10, a cutting machine main body 20, an operation deck 30, an operation unit 40, a control unit 50A, and a switching unit 60.

[0073] The control unit 50A is a control device capable of controlling a part or the whole of the cutting machine 1A, similar to the control unit 50 of the first embodiment. The control unit 50A controls the cutting machine 1A based on, for example, an operation input to the operation unit 40, and causes the cutting head 27 to cut the workpiece placed on the surface plate 10.

[0074] Similar to the control unit 50 of the first embodiment, the control unit 50A opens and closes the flow path in the switching unit 60 so that either the first gas GA or the second gas GB flows into the cutting head 27, thereby switching the assist gas flowing into the cutting head 27.

[0075] The control unit 50A switches the assist gas flowing into the cutting head 27 from the switching unit 60 based on the cutting area of ​​the workpiece cut by the cutting head 27. For example, the control unit 50A switches the assist gas based on the cutting area input by the operator to the operation unit 40.

[0076] In the following description, the cutting area of ​​the workpiece cut by the cutting machine 1 during peripheral cutting, which is larger than the cutting area of ​​a fine shape such as a small hole, is referred to as the "first area." Also, the cutting area during cutting of a fine shape such as a small hole, which is smaller than the first area, is referred to as the "second area."

[0077] Here, the first area and the second area are area regions that are distinguished based on a predetermined value and have a predetermined width. The first area is a shape area that is equal to or greater than the predetermined value. The second area is a shape area that is less than the predetermined value. For example, the first area is 400 mm ２ The above shape area is shown. The second area is 400 mm ２ Indicates a shape area less than .

[0078] When the cutting area is the first area, the control unit 50A controls the switching unit 60 to eject the first gas GA from the cutting head 27 as the assist gas.

[0079] As described above, Fig. 3 is a photograph showing the back surface of a workpiece that has been peripherally cut using the first gas GA. That is, Fig. 3 shows the workpiece that has been cut using the first gas GA when the cutting area is the first area.

[0080] As described above, Fig. 4 is a photograph showing the back surface of a workpiece that has been peripherally cut using the second gas GB. That is, Fig. 4 shows the workpiece that has been cut using the second gas GB when the cutting area is the first area.

[0081] As shown in Figures 3 and 4, when the cut area of ​​the workpiece is the first area, the amount of dross adhering to the back surface of the workpiece cut using the first gas GA as the assist gas is less than the amount of dross adhering to the back surface of the workpiece cut using the second gas GB as the assist gas.

[0082] When the cutting area is the second area, the control unit 50A controls the switching unit 60 to eject the second gas GB from the cutting head 27 as the assist gas.

[0083] As described above, Fig. 5 is a photograph showing the back surface of a workpiece that has been subjected to small hole cutting using the second gas GB. That is, Fig. 5 shows the workpiece that has been cut using the second gas GB when the cutting area is the second area.

[0084] As described above, Fig. 6 is a photograph showing the back surface of a workpiece that has been subjected to small hole cutting using the first gas GA. That is, Fig. 6 shows the workpiece that has been cut using the first gas GA when the cutting area is the second area.

[0085] As shown in Figures 5 and 6, when the cut area of ​​the workpiece is the second area, the amount of dross adhering to the back surface of the workpiece cut using the second gas GB as the assist gas is less than the amount of dross adhering to the back surface of the workpiece cut using the first gas GA as the assist gas.

[0086] When the control unit 50A determines that the cutting area for cutting the workpiece is a first area, it switches the flow path within the switching unit 60 so that the first gas GA is injected from the cutting head 27. When the control unit 50A determines that the cutting area for cutting the workpiece is a second area, it switches the flow path within the switching unit 60 so that the second gas GB is injected from the cutting head 27.

[0087] The memory of the control unit 50A stores a cutting condition database in which the cutting area is associated with the assist gas. The control unit 50A references the cutting condition database and selects an assist gas based on the cutting area. The control unit 50A controls the switching unit 60 based on the selected assist gas to change the assist gas injected from the cutting head 27.

[0088] The cutting machine 1A of this embodiment is equipped with an injection section (cutting head) 27 that can inject a laser and an assist gas onto the workpiece to cut the workpiece, a switching section 60 that can supply a first gas GA and a second gas GB that has a higher nitrogen concentration than the first gas GA as assist gases to the injection section 27 and can switch the assist gas supplied to the injection section 27, and a control section 50A that can change the assist gas that the switching section 60 supplies to the injection section 27 by controlling the switching section 60.

[0089] The control unit 50A changes the assist gas supplied to the injection unit 27 based on the cutting area.

[0090] For example, when the cutting area of ​​the workpiece is a first area, which is a large area for cutting an outer periphery or the like, the control unit 50A supplies the first gas GA from the switching unit 60 to the injection unit 27. Furthermore, when the cutting area of ​​the workpiece is a second area, which is a smaller area than the first area for cutting a small hole or the like, the control unit 50A supplies the second gas GB from the switching unit 60 to the injection unit 27.

[0091] As a result, it is possible to provide a cutting machine 1A and a cutting method that can suppress the adhesion of dross regardless of the cut shape of the workpiece.

[0092] Although the embodiments of the present disclosure have been described above in detail with reference to the drawings, the specific configurations are not limited to these embodiments and include design modifications within the scope of the present disclosure. Furthermore, the components shown in the above-described embodiments and the modified examples shown below can be configured in any suitable combination.

[0093] (Modification 1) In each of the above-described embodiments, the switching unit 60 switches the assist gas using a three-way valve, but the mode of the switching unit is not limited to this.

[0094] The switching unit may switch the assist gas by switching between a plurality of gas circuits using an electromagnetic valve, or may switch the assist gas by using a mass flow controller with high flow rate and high pressure specifications.

[0095] (Variation 2) In each of the above embodiments, the cutting machine 1, 1A switches the assist gas for each workpiece based on the cutting speed or the cutting area, but the cutting machine is not limited to this. The cutting machine may switch the assist gas for each cutting location based on the cutting speed or the cutting area.

[0096] For example, when peripheral cutting and small hole cutting are performed on the same workpiece, the cutting machine switches the assist gas based on the cutting speed or cutting area set for each cutting location.

[0097] In this case, the cutting machine uses a first gas GA when cutting a cutting portion (e.g., the outer periphery) at a first speed for the same workpiece, and uses a second gas GB when cutting a cutting portion (e.g., a small hole) at a second speed.

[0098] Furthermore, the cutting machine uses a first gas GA when cutting a cutting portion having a first cutting area (e.g., the outer periphery) for the same workpiece, and uses a second gas GB when cutting a cutting portion having a second cutting area (e.g., a small hole).

[0099] (Variation 3) In each of the above embodiments, the assist gases used by the cutting machine 1, 1A are the first gas GA and the second gas GB, but the types of assist gases used by the cutting machine are not limited to this. The cutting machine may be configured to be able to switch between three or more assist gases.

[0100] When the switching unit can switch between three types of assist gas, the control unit determines which of three speed ranges (first speed, second speed, third speed) distinguished by a predetermined value the cutting speed is in, and ejects the assist gas corresponding to the determined cutting speed from the cutting head 27.

[0101] The control unit also determines which of three area regions (first area, second area, third area) the cutting area is distinguished by a predetermined value, and ejects assist gas corresponding to the determined cutting area from the cutting head 27.

[0102] (Modification 4) In the above embodiments, the cutting machines 1 and 1A are gantry-type laser cutting machines, but they may be laser cutting machines other than the gantry type, such as bed-type machines.

[0103] 1, 1A Cutting machine 10 Surface plate 20 Cutting machine main body 27 Cutting head (injection part) 50, 50A Control part 60 Switching part

Claims

1. A cutting machine comprising: an injection unit capable of injecting a laser and an assist gas onto a workpiece to cut the workpiece; a switching unit capable of supplying a first gas and a second gas having a higher nitrogen concentration than the first gas as the assist gas to the injection unit and capable of switching the assist gas supplied to the injection unit; and a control unit capable of controlling the switching unit to change the assist gas supplied to the injection unit by the switching unit, wherein the injection unit can change the cutting speed at which the workpiece is cut to a first speed or a second speed slower than the first speed, and the control unit changes the assist gas supplied to the injection unit based on the cutting speed.

2. The cutting machine according to claim 1, wherein the control unit supplies the first gas from the switching unit to the injection unit when the cutting speed is the first speed, and supplies the second gas from the switching unit to the injection unit when the cutting speed is the second speed.

3. A cutting method for cutting a workpiece by injecting a laser and an assist gas into the workpiece, wherein the assist gas injected into the workpiece is switched to a first gas or a second gas having a higher nitrogen concentration than the first gas based on the cutting speed at which the workpiece is cut.

4. The cutting method according to claim 3, wherein the first gas is injected into the workpiece when the cutting speed is a first speed that is in a higher speed range of the cutting speeds, and the second gas is injected into the workpiece when the cutting speed is a second speed that is slower than the first speed.

5. A cutting machine comprising: an injection unit capable of injecting a laser and an assist gas onto a workpiece to cut the workpiece; a switching unit capable of supplying a first gas and a second gas having a higher nitrogen concentration than the first gas as the assist gas to the injection unit and capable of switching the assist gas supplied to the injection unit; and a control unit capable of controlling the switching unit to change the assist gas supplied to the injection unit by the switching unit, wherein the control unit changes the assist gas supplied to the injection unit based on the cutting area of the workpiece cut by the injection unit.

6. The cutting machine according to claim 5, wherein the control unit supplies the first gas from the switching unit to the injection unit when the cutting area is a first area, which is a larger area region of the cutting area, and supplies the second gas from the switching unit to the injection unit when the cutting area is a second area, which is a smaller area region than the first area.

7. A cutting method for cutting a workpiece by injecting a laser and an assist gas into the workpiece, wherein the assist gas injected into the workpiece is switched to a first gas or a second gas having a higher nitrogen concentration than the first gas based on the cutting area of the workpiece.

8. The cutting method according to claim 7, wherein the first gas is injected into the workpiece when the cutting area is a first area that is a larger area region of the cutting area, and the second gas is injected into the workpiece when the cutting area is a second area that is smaller than the first area.

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