Sheet metal welding method, processing program creation method, and processing program creation device

Abstract

This sheet metal welding method comprises: acquiring a processing program for cutting a sheet metal from a base material and welding the sheet metal, the base material having a plating layer formed thereon; acquiring cutting positions for cutting the sheet metal from the acquired processing program; identifying a welded cutting position which is a cutting position for welding from the acquired cutting positions; setting irradiation regions for irradiation with a laser beam from a laser processing machine (100) on both sides of the identified welded cutting position; irradiating the set irradiation regions with the laser beam to remove the plating layer; irradiating the cutting position with the laser beam to cut out the sheet metal from the base material; and welding the sheet metal that has been cut out.

Description

Sheet metal welding method, machining program creation method, and machining program creation device

[0001] The present disclosure relates to a sheet metal welding method, a processing program creation method, and a processing program creation device.

[0002] Patent Document 1 discloses a laser cutting method for cutting a plated steel sheet with a laser beam. In the laser cutting method disclosed in Patent Document 1, a metal contained in a plating layer is melted by irradiation with a laser beam and allowed to flow into the cut surface of the plated steel sheet.

[0003] Japanese Patent Application Laid-Open No. 2019-69457

[0004] However, in the conventional laser cutting method described above, the molten plating layer-containing metal is caused to flow onto the cut surface. Therefore, when the cut surface into which the plating layer-containing metal has flowed is welded, the welding quality deteriorates, and there is room for improvement.

[0005] A first aspect of one or more embodiments is a sheet metal welding method that includes acquiring a processing program for cutting out sheet metal from a base material having a plating layer formed thereon and welding the sheet metal, acquiring cutting positions for cutting the sheet metal from the acquired processing program, identifying welding cutting positions that are cutting positions to be welded from the acquired cutting positions, setting irradiation areas on both sides of the identified welding cutting positions where a laser beam is irradiated from a laser processing machine, irradiating the set irradiation areas with a laser beam to remove the plating layer, irradiating the cutting position with a laser beam to cut out the sheet metal from the base material, and welding the cut-out sheet metal.

[0006] A second aspect of one or more embodiments is a method for creating a processing program, which includes acquiring design data for a product formed from sheet metal cut out from a base material on which a plating layer is formed, identifying a welding edge portion to be welded from among the edge portions of the product based on the design data, setting a plating removal area in which the plating layer is removed adjacent to the cut surfaces of multiple pieces of the sheet metal joined at the identified welding edge portion, generating an unfolded view of the sheet metal in which the plating removal area is set, and creating a processing program for cutting out the sheet metal from the base material and welding it based on the generated unfolded view.

[0007] A third aspect of one or more embodiments is a processing program creation device that acquires design data of a product formed from sheet metal cut out from a base material on which a plating layer is formed, identifies a welding edge portion to be welded from among edge portions of the product based on the design data, sets a plating removal area in contact with cut surfaces of multiple pieces of the sheet metal joined at the identified welding edge portion to remove the plating layer, generates an unfolded view of the sheet metal in which the plating removal area is set, and creates a processing program for cutting out the sheet metal from the base material and welding it based on the generated unfolded view.

[0008] According to one or more embodiments of the sheet metal welding method, the plating layer on both sides of the cutting position to be welded is removed in advance, which prevents the metal components of the plating layer that melts during cutting from flowing into the cut surface, thereby improving the welding quality even when cutting a plated steel sheet and welding the cut surface.

[0009] According to the sheet metal welding method of one or more embodiments, it is possible to improve the welding quality even when cutting a plated steel sheet and welding the cut surfaces.

[0010] FIG. 1 is a diagram showing the overall configuration of a laser processing machine used in the sheet metal welding method according to the first embodiment. FIG. 2 is a perspective view showing the detailed configuration of a collimator unit and a processing head of the laser processing machine used in the sheet metal welding method according to the first embodiment. FIG. 3 is a diagram for explaining the displacement of the irradiation position of the laser beam on the sheet metal by a beam vibration mechanism. FIG. 4 is a flowchart showing the processing procedure of the sheet metal welding process according to the first embodiment. FIG. 5 is a diagram for explaining a method for removing a plating layer from a sheet metal using the sheet metal welding method according to the first embodiment. FIG. 6 is a diagram showing an example of sheet metal welding using the sheet metal welding method according to the first embodiment. FIG. 7 is an enlarged top view of a welded portion of a sheet metal using the sheet metal welding method according to the first embodiment. FIG. 8 is a diagram for explaining a method for removing a plating layer from a sheet metal using the sheet metal welding method according to the first embodiment. FIG. 9 is a diagram for explaining a method for vibrating a laser beam of the laser processing machine used in the sheet metal welding method according to the first embodiment. FIG. 10 is a diagram for explaining a method for vibrating a laser beam of the laser processing machine used in the sheet metal welding method according to the first embodiment. FIG. 11 is a diagram for explaining a method of aligning metal sheets by the metal sheet welding method according to the first embodiment. FIG. 12 is a diagram showing the overall configuration of a laser processing machine used in the processing program creation method according to the second embodiment. FIG. 13 is a flowchart showing the processing procedure of the processing program creation process according to the second embodiment. FIG. 14 is a diagram showing an example of a display screen displayed on the processing program creation device according to the second embodiment. FIG. 15 is a diagram showing the welding state of metal sheets in the case of one-way pull. FIG. 16 is a diagram showing the welding state of metal sheets in the case of half-way pull. FIG. 17 is a diagram showing an example of a 3D model displayed on the processing program creation device according to the second embodiment. FIG. 18 is a diagram showing an example of a 3D model displayed on the processing program creation device according to the second embodiment. FIG. 19 is a diagram showing an example of a development generated by the processing program creation device according to the second embodiment.

[0011] First Embodiment Hereinafter, a sheet metal welding method according to the first embodiment will be described with reference to the drawings. The sheet metal welding method according to the first embodiment includes acquiring a processing program for cutting out a sheet metal from a base material having a plating layer formed thereon and welding the sheet metal, acquiring cutting positions for cutting the sheet metal from the acquired processing program, identifying welding cutting positions that are cutting positions to be welded from the acquired cutting positions, setting irradiation areas on both sides of the identified welding cutting positions where a laser beam is irradiated from a laser processing machine, irradiating the set irradiation areas with the laser beam to remove the plating layer, irradiating the cutting positions with the laser beam to cut out the sheet metal from the base material, and welding the cut sheet metal.

[0012] [Configuration of Laser Processing Machine] Fig. 1 is a diagram showing the overall configuration of a laser processing machine used in the sheet metal welding method according to the first embodiment, and Fig. 2 is a perspective view showing the detailed configuration of a collimator unit and a processing head in the laser processing machine. In Fig. 1, the laser processing machine 100 includes a laser oscillator 10 that generates and emits a laser beam, a laser processing unit 20, and a process fiber 12 that transmits the laser beam emitted from the laser oscillator 10 to the laser processing unit 20. Note that the process fiber 12 may be single-core or multi-clad, and an optical coupler may be provided on the transmission path to the laser processing unit 20.

[0013] The laser processing machine 100 includes an NC (numerical control) device 50, a processing program database 60, and an assist gas supply device 70. The NC device 50 is an example of a control device that controls each part of the laser processing machine 100. The processing program database 60 may be configured external to the laser processing machine 100. In this case, the processing program database 60 may be connected to the laser processing machine 100 via a network.

[0014] A laser oscillator that amplifies pumping light emitted from a laser diode to emit a laser beam of a predetermined wavelength, or a laser oscillator that directly utilizes a laser beam emitted from a laser diode, is suitable as the laser oscillator 10. Examples of the laser oscillator 10 include a solid-state laser oscillator, a fiber laser oscillator, a disk laser oscillator, and a direct diode laser oscillator (DDL oscillator).

[0015] The laser processing unit 20 includes a processing table 21 on which the sheet metal W to be processed, which is the base material, is placed, and a processing head 35 having a nozzle 36 attached to its tip, which emits a laser beam from a circular opening 36a onto the sheet metal W. The laser processing unit 20 also includes a gate-shaped X-axis carriage 22 and a Y-axis carriage 23 which move the processing head 35 to the processing position, and the processing head 35 is connected to a collimator unit 30 fixed to the Y-axis carriage 23.

[0016] The X-axis carriage 22 is configured to be movable in the X-axis direction on the processing table 21. The Y-axis carriage 23 is configured to be movable in the Y-axis direction perpendicular to the X-axis on the X-axis carriage 22. The X-axis carriage 22 and the Y-axis carriage 23 function as a movement mechanism that moves the collimator unit 30 and the processing head 35 along the surface of the metal sheet W in the X-axis direction, the Y-axis direction, or any combined direction of the X-axis and the Y-axis.

[0017] Instead of moving the collimator unit 30 and the processing head 35 along the surface of the metal sheet W, the collimator unit 30 and the processing head 35 may be configured to be fixed in position and the metal sheet W may be moved. The laser processing machine 100 may be provided with a movement mechanism that moves the relative positions of the collimator unit 30 and the processing head 35 with respect to the surface of the metal sheet W.

[0018] The NC device 50 controls the X-axis carriage 22 and the Y-axis carriage 23 so that the processing head 35 moves along the surface of the metal sheet W, and can vibrate the laser beam in a predetermined direction on the surface of the metal sheet W. Furthermore, the NC device 50 can vibrate the laser beam to vibrate the beam spot formed on the surface of the metal sheet W. In this way, the NC device 50 controls the laser processing machine 100 to irradiate the metal sheet W with the laser beam to remove a plating layer formed on the metal sheet W and cut the metal sheet W.

[0019] The NC device 50 is configured by a computer having a memory, a processor such as a CPU (Central Processing Unit), and various interfaces. The memory and various interfaces are connected to the processor via a bus. By having the processor execute a program stored in the memory, the NC device 50 irradiates a laser beam to remove the plating layer and perform a process of cutting the metal sheet W.

[0020] The processing program database 60 stores a processing program for cutting out and welding a metal sheet from a base material on which a plating layer has been formed. The processing program database 60 also stores information for controlling the removal of the plating layer and the cutting of the metal sheet by the laser processing machine 100. The NC device 50 reads the processing program from the processing program database 60, and executes control to vibrate the beam spot on the surface of the metal sheet W and to move the processing head 35 along the surface of the metal sheet W.

[0021] The assist gas supply device 70 supplies assist gas to the processing head 35 when processing the metal sheet W. When the metal sheet W to be processed is an iron-based material, the assist gas supply device 70 can use oxygen, nitrogen, or air as the assist gas. The assist gas supplied to the processing head 35 is sprayed from the opening 36a in a direction perpendicular to the metal sheet W. The assist gas expels molten metal from the metal sheet W.

[0022] 2, the collimator unit 30 includes a collimation lens 31 that converts the divergent laser beam emitted from the process fiber 12 into parallel light (collimated light). The collimator unit 30 also includes a galvano scanner unit 32 and a bend mirror 33 that reflects the laser beam emitted from the galvano scanner unit 32 downward in the Z-axis direction, which is perpendicular to the X-axis and Y-axis.

[0023] The processing head 35 is equipped with a focusing lens 34 that focuses the laser beam reflected by the bend mirror 33 and irradiates the laser beam onto the metal plate W. The divergent laser beam emitted from the process fiber 12 travels so that the center of its optical axis is located at the center of the collimation lens 31.

[0024] The laser processing machine 100 is centered so that the laser beam emitted from the opening 36a of the nozzle 36 is positioned at the center of the opening 36a. In the reference state, the laser beam is emitted from the center of the opening 36a. The galvano scanner unit 32 functions as a beam vibration mechanism that vibrates the laser beam, which travels through the processing head 35 and is emitted from the opening 36a, within the opening 36a. How the galvano scanner unit 32 vibrates the laser beam will be described later.

[0025] The galvano scanner unit 32 has a scan mirror 321 that reflects the laser beam emitted from the collimation lens 31, and a drive unit 322 that rotates the scan mirror 321 to a predetermined angle. The galvano scanner unit 32 also has a scan mirror 323 that reflects the laser beam emitted from the scan mirror 321, and a drive unit 324 that rotates the scan mirror 323 to a predetermined angle. The scan mirrors 321 and 323 are installed so as to rotate in different directions.

[0026] The driving units 322 and 324 can set the scan mirrors 321 and 323 to predetermined angles, respectively, based on the control of the NC device 50. The driving units 322 and 324 can also oscillate the scan mirrors 321 and 323 back and forth within a predetermined angular range.

[0027] The galvano scanner unit 32 can move the beam spot of the laser beam irradiated onto the metal sheet W by changing the angle of either or both of the scan mirror 321 and the scan mirror 323. Furthermore, the galvano scanner unit 32 can vibrate the beam spot of the laser beam by reciprocatingly vibrating either or both of the scan mirror 321 and the scan mirror 323. Note that the galvano scanner unit 32 is an example of a beam vibration mechanism, and the beam vibration mechanism is not limited to the galvano scanner unit 32 having a pair of scan mirrors.

[0028] 3 is a diagram for explaining the displacement of the irradiation position of the laser beam on the metal sheet W by the galvano scanner unit 32. Here, the diagram shows a state in which one or both of the scan mirrors 321 and 323 are tilted, displacing the position of the laser beam irradiated on the metal sheet W. In FIG. 3, the thin solid line that is bent by the bend mirror 33 and passes through the focusing lens 34 indicates the optical axis of the laser beam when the laser processing machine 100 is in the reference state.

[0029] In more detail, the angle of the optical axis of the laser beam incident on the bend mirror 33 changes due to the operation of the galvano scanner unit 32 located in front of the bend mirror 33, and the optical axis deviates from the center of the bend mirror 33. For the sake of simplicity, in Fig. 3, the incident position of the laser beam on the bend mirror 33 is shown as the same before and after the operation of the galvano scanner unit 32.

[0030] It is assumed that the optical axis of the laser beam is displaced from the position indicated by the thin solid line to the position indicated by the thick solid line by the action of the galvano scanner unit 32. If the laser beam reflected by the bend mirror 33 is tilted at an angle θ, the irradiation position of the laser beam on the metal sheet W is displaced by a distance Δs. If the focal length of the focusing lens 34 is EFL (effective focal length), the distance Δs is calculated as EFL × sin θ.

[0031] 3, the irradiation position of the laser beam on the metal plate W is displaced by a distance Δs in the direction opposite to the direction shown in Fig. 3. The distance Δs is a distance less than the radius of the opening 36a, and preferably a distance equal to or less than the maximum distance, where the maximum distance is the distance obtained by subtracting a predetermined margin from the radius of the opening 36a.

[0032] [Method for welding sheet metal] Hereinafter, a method for welding sheet metal according to a first embodiment will be described with reference to Fig. 4. Fig. 4 is a flowchart showing the procedure for welding sheet metal. As shown in Fig. 4, in step S101, the NC device 50 acquires a machining program from the machining program database 60. This machining program records a process for cutting out and welding sheet metal from a base material on which a plating layer has been formed.

[0033] In step S103, the NC device 50 acquires, from the machining program acquired in step S101, cutting positions for cutting the metal sheet W. For example, as shown in Fig. 5, when cutting out a metal sheet W1 from the base metal sheet W, the NC device 50 acquires the positions of the four sides that form the outer periphery of the metal sheet W1 as cutting positions P.

[0034] In step S105, the NC device 50 identifies a welding cut position, which is a cut position to be welded, from the cut positions P acquired in step S103. In the example shown in Fig. 5, the NC device 50 refers to the processing program and identifies a welding cut position 51 as a cut position to be welded from the cut positions P on the four sides that form the outer periphery of the sheet metal W1 to be cut out.

[0035] In step S107, the NC device 50 sets irradiation areas on both sides of the welding and cutting position identified in step S105, where the laser beam is irradiated from the laser processing machine 100. For example, as shown in Fig. 6, a case will be described in which the side of a box 80 is formed by one-way pull welding of metal sheets W1 and W2. Fig. 7 shows an enlarged view of the welded portion in this case, viewed from above.

[0036] In FIG. 7 , for ease of viewing, a space is provided between the cut surface X1 and the metal sheet W2. However, as shown in FIG. 7 , the cut surface X1 of the metal sheet W1, cut at the welding and cutting position 51, is welded to the metal sheet W2. Therefore, it is necessary to prevent metal components of the plating layer from flowing into the cut surface X1 at the welding and cutting position 51 of the metal sheet W1. Therefore, as shown in FIG. 5 , the NC device 50 sets an irradiation area E1 of a predetermined width on both sides of the welding and cutting position 51. After this, the plating layer in the irradiation area E1 is removed, so that the metal components of the plating layer will not flow into the cut surface X1 even when the metal sheet W1 is cut at the welding and cutting position 51.

[0037] In this case, the predetermined width of the irradiation area E1 is set to be equal to or greater than the beam diameter of the laser beam during laser cutting. For example, if the beam diameter correction amount is set to 0.08 mm to 0.10 mm in the cutting conditions for the thickness of the target base material, the beam diameter can be expected to be a maximum of 0.20 mm. Therefore, the predetermined width, which is the width of the irradiation area E1, is set to be equal to or greater than the beam diameter of 0.20 mm.

[0038] On the other hand, in the case of the sheet metal W2 shown in Fig. 7, it is necessary not only to prevent the metal components of the plating layer from flowing into the cut surface X2 cut at the welding cutting position 53, but also to remove the plating layer in the welding range X3 of the sheet metal W2 where the cut surface X1 is welded. Therefore, a case of setting an irradiation area on such a sheet metal W2 will be described with reference to Fig. 8. Fig. 8 is a diagram illustrating a case of cutting out the sheet metal W2 from the base metal sheet W.

[0039] As shown in Fig. 8, in the case of sheet metal W2, when welding and cutting position 53 is identified, NC device 50 acquires the position of welding range X3 from the processing program. Here, welding range X3, where cut surface X1 shown in Fig. 7 is welded, is adjacent to welding and cutting position 53 as shown in Fig. 8. Therefore, NC device 50 sets welding range X3, which is adjacent to welding and cutting position 53, as irradiation area E2.

[0040] On the other hand, when cutting is performed at the welding and cutting position 53, the cut surface becomes X2 in Fig. 7. Therefore, the NC device 50 sets an irradiation area E1 of a predetermined width on the opposite side of the welding range X3 of the welding and cutting position 53, as shown in Fig. 8.

[0041] Therefore, the NC device 50 acquires from the processing program a welding range X3 in which welding is performed on the surface of the metal sheet W2 adjacent to the welding and cutting position 53, sets an irradiation area E2 in the acquired welding range X3, and sets an irradiation area E1 of a predetermined width on the opposite side of the welding range X3 at the welding and cutting position 53. In this way, the NC device 50 sets the irradiation areas E1 and E2 for the metal sheet W2.

[0042] In step S109, the NC device 50 irradiates the irradiation areas set in step S107 with a laser beam to remove the plating layer. Specifically, in the case of the sheet metal W1 shown in Fig. 5, the NC device 50 irradiates the irradiation areas E1 on both sides of the welding and cutting position 51 with the laser beam to remove the plating layer. In the case of the sheet metal W2 shown in Fig. 8, the NC device 50 irradiates the irradiation areas E1 and E2 adjacent to the welding and cutting position 53 with the laser beam to remove the plating layer.

[0043] At this time, the NC device 50 acquires the processing conditions from the processing program database 60 and removes the plating layer under the acquired processing conditions. Generally, to remove a zinc plating layer, it is necessary to remove a maximum of 50 μm from the material surface, so the output must be higher than that of laser marking, etc., and the pressure of the assist gas must also be high.

[0044] For example, the processing conditions are set as follows: laser beam moving speed 5000 to 10000 mm / min, output 700 to 1600 W, assist gas pressure 0.5 to 0.8 MPa, and a gap of 5 mm or more between the metal plate W and the tip of the nozzle 36. In addition, in order to prevent an oxide film from forming on the portion where the plating layer has been removed, an inert gas is used as the assist gas.

[0045] These processing conditions are set according to the material of the metal sheet W. For example, when the metal sheet W is a highly corrosion-resistant plated steel sheet, the laser beam movement speed is set to 10,000 mm / min, the output is set to 700 W, and the assist gas pressure is set to 0.8 MPa in removing the plating layer of the metal sheet W1. Also, when removing the plating layer of the metal sheet W2, the laser beam movement speed is set to 5,000 mm / min, the output is set to 1,600 W, and the assist gas pressure is set to 0.8 MPa.

[0046] When removing the plating layer, the NC device 50 controls the driving parts 322, 324 of the galvano scanner unit 32 to vibrate the laser beam at a predetermined vibration amplitude, thereby vibrating the beam spot on the surface of the metal sheet W.

[0047] 9 is a diagram illustrating a method for vibrating the laser beam. As shown in FIG. 9, the maximum vibration amplitude of the laser beam is a width C1, which is the diameter of the opening 36a minus a predetermined margin (G1 + G2). Therefore, the NC device 50 vibrates the laser beam within a range that does not exceed the maximum vibration amplitude C1.

[0048] The NC device 50 also vibrates the laser beam in a direction D2 perpendicular to the laser beam traveling direction D1 to remove the plating layer. As a result, the metal components of the removed plating layer are blown away in the direction F1. In this way, in the case of Figure 9, the plating layer is removed by vibrating the laser beam with a predetermined vibration amplitude and vibrating the beam spot formed on the surface of the sheet metal W in the direction D2 perpendicular to the laser beam traveling direction D1.

[0049] It is also possible to change the vibration direction of the laser beam. For example, as shown in Fig. 10, the beam spot may be vibrated so as to describe a semicircle C2 in the laser beam traveling direction D1. That is, in the case of Fig. 10, the laser beam is vibrated by a predetermined vibration amplitude, and the beam spot formed on the surface of the metal sheet W is vibrated so as to describe a semicircle C2 in the laser beam traveling direction D1, thereby removing the plating layer.

[0050] In this case, the metal components of the removed plating layer are blown away in the direction of F2. Therefore, the metal components of the removed plating layer are blown away backward relative to the laser beam traveling direction D1, so the amount of metal components attached can be reduced compared to the case of Fig. 9. For example, the adhesion rate of metal components to the sheet metal surface (volume of attached metal components / volume of removed metal components) is 20% in the case of Fig. 9, but is reduced to 14% in the case of Fig. 10.

[0051] Furthermore, when performing the process of removing the plating layer, the NC device 50 first sets the vibration center. For example, in the case shown in FIG. 5 , the NC device 50 sets the vibration center D at the same position as the welding and cutting position 51. The NC device 50 then sets the laser beam to vibrate from the vibration center D by a width equal to the irradiation area E1. As a result, the plating layer is removed in an area with a vibration width E (2×E1) centered on the vibration center D. For example, if the width of the irradiation area E1 is 0.20 mm, the vibration width E is 0.40 mm.

[0052] 8, the NC device 50 sets the vibration center D at a position that is a distance L from the weld cutting position 53. For example, if the width of the irradiation area E1 is 0.20 mm and the thickness of the metal sheet W1 is 2.30 mm, the width of the irradiation area E2 will be 2.30 mm. In this case, the distance L can be calculated using the formula L = (E1 + E2) / 2 - E1 = (E2 - E1) / 2, so that L = 1.05 mm.

[0053] When the vibration center D is set at the position of the calculated distance L, the NC device 50 sets the laser beam to vibrate at a width of (E1 + E2) / 2 from the vibration center D. As a result, the plating layer is removed in an area with a vibration width E (E1 + E2) centered on the vibration center D. For example, if the width of the irradiation area E1 is 0.20 mm and the width of the irradiation area E2 is 2.30 mm, the vibration width E will be 2.50 mm. In this way, the NC device 50 executes the process of removing the plating layer.

[0054] In step S111, the NC device 50 controls the laser beam to be irradiated onto the cutting position P to cut out the metal sheets W1 and W2 from the metal sheet W serving as the base material. Specifically, in the case of Fig. 5, the NC device 50 irradiates the laser beam onto the cutting position P that forms the outer periphery of the metal sheet W1, cuts the metal sheet W1, and cuts out the metal sheet W1 from the metal sheet W. Similarly, in the case of Fig. 8, the NC device 50 irradiates the laser beam onto the cutting position P that forms the outer periphery of the metal sheet W2, cuts the metal sheet W2, and cuts out the metal sheet W2 from the metal sheet W.

[0055] In step S113, the metal sheets cut out in step S111 are welded. Specifically, as shown in Fig. 6, the cut metal sheets W1 and W2 are butted together and welded using a laser welder (not shown) to create box 80. The laser welder that welds the metal sheets W1 and W2 may be any laser welder, such as an existing robot type or handheld type.

[0056] 11, when the plating layer is removed from the welding area 91 where the metal sheet W1 is to be welded, protrusions 93 are formed around the welding area 91 by the metal components of the removed plating layer. These protrusions 93 have a height of about 100 μm, and can be used for alignment when the metal sheets W1 and W2 are butted together.

[0057] Therefore, the laser processing machine 100 irradiates an irradiation area set in the welding area 91 with a laser beam to remove the plating layer, and forms protrusions 93 around the welding area 91 using the metal components of the removed plating layer. The metal sheet W1 is then aligned using the formed protrusions 93, and the metal sheets W1 and W2 are welded together. This completes the metal sheet welding process according to this embodiment.

[0058] Effect of the First Embodiment As described above in detail, the sheet metal welding method according to the first embodiment acquires cutting positions for cutting the sheet metal from a processing program, identifies welding cutting positions from among the acquired cutting positions, sets irradiation areas on both sides of the identified welding cutting position, irradiates the set irradiation areas with the laser beam to remove the plating layer, irradiates the cutting position with the laser beam to cut the sheet metal from the base material, and welds the cut sheet metal. This removes the plating layer on both sides of the cutting position to be welded, thereby preventing metal components of the molten plating layer from flowing into the cut surface during cutting. Therefore, welding quality can be improved even when cutting a plated steel sheet and welding the cut surface.

[0059] In particular, when welding materials with thick plating layers such as zinc, the welding quality is reduced due to the occurrence of pits and bit holes, but in this embodiment, the plating layer is removed before welding, so the welding quality can be improved. Furthermore, the work time can be significantly reduced compared to when metal components of the plating layer that have flowed into the cut surface are removed with a grinder or laser cleaning device.

[0060] In the sheet metal welding method according to the first embodiment, irradiation areas of a predetermined width are set on both sides of the weld cut position. This allows the plating layer on both sides of the cut position to be removed by a predetermined width, preventing the metal components of the plating layer melted during cutting from flowing into the cut surface. This improves welding quality even when cutting a plated steel sheet and welding the cut surface.

[0061] Furthermore, in the sheet metal welding method according to the first embodiment, a welding area where welding is performed on the surface of the sheet metal adjacent to the welding cut position is obtained from the processing program, an irradiation area is set in the obtained welding area, and an irradiation area of ​​a predetermined width is set on the opposite side of the welding area from the welding cut position. This makes it possible to remove the plating layer in the welding area even when welding is performed on the surface of the sheet metal adjacent to the welding cut position, thereby improving welding quality.

[0062] In the sheet metal welding method according to the first embodiment, the predetermined width of the irradiation area is set to be equal to or greater than the beam diameter of the laser beam used for laser cutting. This allows the plating layer to be removed from the cutting position to be welded by a width equal to or greater than the beam diameter used for laser cutting, thereby preventing the metal components of the plating layer melted during cutting from flowing into the cut surface. This improves welding quality even when cutting a plated steel sheet and welding the cut surface.

[0063] Furthermore, in the sheet metal welding method according to the first embodiment, the plating layer is removed by vibrating the laser beam at a predetermined vibration amplitude and vibrating the beam spot formed on the surface of the sheet metal W in a direction perpendicular to the direction of travel of the laser beam. This allows the plating layer to be easily removed using the galvano scanner unit 32, thereby shortening the work time.

[0064] In the sheet metal welding method according to the first embodiment, the plating layer is removed by vibrating the laser beam at a predetermined vibration amplitude, and vibrating the beam spot formed on the surface of the sheet metal W in a semicircular pattern in the direction of travel of the laser beam. This allows the metal components of the removed plating layer to be blown away backward relative to the direction D1 of travel of the laser beam, thereby reducing the amount of metal components adhering to the sheet metal.

[0065] Furthermore, in the sheet metal welding method according to the first embodiment, a laser beam is irradiated onto an irradiation area set in the welding range 91 to remove the plating layer, protrusions 93 are formed around the welding range 91 using the metal components of the removed plating layer, and the sheet metal W1 is aligned using the formed protrusions 93 to weld the sheet metal W1 and the sheet metal W2. This allows the sheet metal W1 to be aligned using the metal components removed from the plating layer, so accurate alignment can be achieved even for joints where alignment is difficult, such as with half-draw welding.

[0066] [Second embodiment] A method for creating a processing program according to a second embodiment will be described below with reference to the drawings. In the drawings, the same parts are designated by the same reference numerals, and detailed description thereof will be omitted. In the second embodiment, a processing program to be used in the laser processing machine 100 described in the first embodiment is created.

[0067] [Configuration of Laser Processing Machine] Fig. 12 is a diagram showing the overall configuration of a laser processing machine used in the processing program creation method according to the second embodiment. The second embodiment differs from the laser processing machine 100 of the first embodiment in that the laser processing machine 100 further includes a CAD / CAM (Computer Aided Design / Computer Aided Manufacturing) device 120. The CAD / CAM device 120 may be external to the laser processing machine 100. In this case, the CAD / CAM device 120 may be connected to the laser processing machine 100 via a network.

[0068] The CAD / CAM device 120 is a device that imports CAD data of the sheet metal to be laser processed and creates a development drawing and a processing program required to execute the laser processing. In particular, in this embodiment, the CAD / CAM device 120 functions as a processing program creation device 121 that creates a processing program. The processing program creation device 121 is a device that creates a processing program for cutting out and welding the sheet metal from a base material on which a plating layer has been formed, and includes a control unit 123 and a memory unit 125.

[0069] The control unit 123 executes a process for creating a machining program from the 3D CAD data. Specifically, the control unit 123 acquires design data for a product formed from a metal sheet cut from a base material on which a plating layer is formed, and identifies welding edges to be welded from among the edge portions of the product based on the acquired design data. The control unit 123 then sets a plating removal region in which the plating layer is removed, adjacent to the cut surfaces of the multiple metal sheets joined at the identified welding edges, generates a development of the metal sheet in which the plating removal region is set, and creates a machining program based on the generated development.

[0070] The storage unit 125 is a memory or database that stores data necessary to execute the process of creating a machining program, and stores, for example, 3D CAD data imported from outside, generated development drawings, and created machining programs.

[0071] The machining program creating device 121 is configured by a computer having a memory, a processor such as a CPU (Central Processing Unit), and various interfaces. The memory and various interfaces are connected to the processor via a bus. The processor executes a program stored in the memory, and the machining program creating device 121 executes a process of creating a machining program.

[0072] [Method for Creating a Machining Program] A method for creating a machining program according to the second embodiment will be described below with reference to Fig. 13. Fig. 13 is a flowchart showing the processing steps for creating a machining program. As shown in Fig. 13, in step S201, the control unit 123 acquires three-dimensional CAD data as design data for a product formed from a metal sheet cut out from a base material on which a plating layer is formed. For example, the three-dimensional CAD data for the box 80 in Fig. 6 described in the first embodiment is acquired.

[0073] In step S203, the control unit 123 activates a "welding setting" command. For example, as shown in FIG. 14, when the user presses the "welding setting" command button 140 on the screen of the CAD / CAM device 120, the control unit 123 displays an operation screen 141 for "welding setting." When the user selects "welding 1" from the welding attributes on the operation screen 141, an enlarged view of the edge portion where the weld line L1 is set is displayed. The flanges 142 and 143 joined at this edge portion are part of the sheet metal.

[0074] The control unit 123 determines that the portion where the flanges 142 and 143 are joined is a weld portion based on the joining state of the flanges 142 and 143 recorded in the 3D CAD data acquired in step S201. That is, the control unit 123 identifies, from among the edge portions of the product based on the design data, an edge portion to be welded as a weld edge portion. As a result, the control unit 123 displays a weld line L1 at the identified weld edge portion.

[0075] In step S205, the control unit 123 executes the processing instructions input by the user. For example, when the user selects "welding 1" on the operation screen 141, the user can specify parameters for the weld line L1 from the operation screen 141. The parameters include, for example, the offset amount of the start point or end point and the type of joint, as well as continuous welding or intermittent welding as the welding method. Furthermore, the user can specify fiber laser welding, arc welding, or the like as the welding type.

[0076] Furthermore, the user selects a check box 144 for "Joint Plating Removal" and a check box 145 for "Cut Plating Removal" from the "Processing Technology Method" field on the operation screen 141. This causes the control unit 123 to set a plating removal area on the sheet metal. The plating removal area is an area where the plating layer formed on the sheet metal is removed. The plating removal area includes a cut plating removal area that is set to prevent the metal components of the molten plating layer from flowing into the cut surface when the sheet metal is cut, and a joint plating removal area that is set on the surface of the sheet metal where the cut surface of the sheet metal is joined.

[0077] First, the control unit 123 determines the type of joint between the flanges 142 and 143 based on the 3D CAD data acquired in step S201. For example, Fig. 15 is a top view of the welded portion between the flanges 142 and 143 shown in Fig. 14. As shown in Fig. 15, the entire cut surface 151 of the flange 143 is joined to the flange 142, so the control unit 123 determines that the type of joint is a flush corner joint.

[0078] When the type of joint is determined, the control unit 123 sets a plating removal region in contact with the cut surfaces of the flanges 142 and 143 joined at the identified welding edge portion. At this time, the control unit 123 sets the cut portion plating removal region and the joint portion plating removal region based on the joining state of the flanges 142 and 143 joined at the welding edge portion.

[0079] For example, as shown in Figure 15, the cut surface 151 of the flange 143 is joined to the surface of the flange 142, and based on this joining state, the control unit 123 sets a cut portion plating removal area 152 and a joint portion plating removal area 153.

[0080] As a result, the cut portion plating removal region 152 is set in contact with the cut surface 151 so that the metal components of the molten plating layer do not flow into the cut surface 151 when the sheet metal is cut out. This cut portion plating removal region 152 corresponds to the irradiation region E1 shown in Fig. 5 of the first embodiment.

[0081] Furthermore, the joint plating removal region 153 is set in contact with the cut surface 154 on the surface portion of the flange 142 to which the cut surface 151 of the flange 143 is joined. This joint plating removal region 153 corresponds to the irradiation region E2 shown in Figure 8 of the first embodiment.

[0082] The joint may also be a flush corner joint, in which half of a cut surface 151 of a flange 143 is joined to a flange 142, as shown in Figure 16. In this case, a cut plating removal region 152 and a joint plating removal region 153 are set, as shown in Figure 16. However, the width of the joint plating removal region 153 may be narrower than in the case of a single-pull corner joint.

[0083] In step S207, the control unit 123 displays a 3D model that reflects the processing instructions executed in step S205. For example, as shown in Fig. 17, in the product shape of the 3D model, the cut portion plating removal region 152 is set to the flange 143 and displayed, and as shown in Fig. 18, the joint portion plating removal region 153 is set to the flange 142 and displayed. At this time, if parameters are specified on the operation screen 141, the 3D model is displayed according to the specified parameters.

[0084] In step S209, when the user who confirmed the 3D model displayed in step S207 inputs an instruction to create a development, the control unit 123 generates the development. For example, the development shown in Fig. 19 is generated from the 3D models shown in Figs. 17 and 18. In Fig. 19, a cut portion plating removal region 152 is set along a cut surface 151 of the flange 143, a joint portion plating removal region 153 is set along a cut surface 154 of the flange 142, and bend lines 156 and 157 for bending in the bending process are also set. In this way, the processing instructions are reflected and a development of the sheet metal with the set plating removal regions is generated.

[0085] In step S211, the control unit 123 creates a processing program for cutting out and welding the metal sheet from the base material on which the plating layer is formed, based on the development view created in step S209, and ends the processing program creation process according to this embodiment. The created processing program is output to the processing program database 60, and the NC device 50 reads the processing program and performs the metal sheet welding process described in the first embodiment.

[0086] [Effects of the Second Embodiment] As described above in detail, the machining program creation method according to the second embodiment acquires design data for a product formed from sheet metal cut from a base material on which a plating layer is formed, identifies a welding edge from among edge portions of the product based on the design data, sets a plating removal region adjacent to the cut surfaces of multiple sheet metals joined at the welding edge, generates a development view of the sheet metal in which the plating removal region is set, and creates a machining program for cutting the sheet metal from the base material and welding it based on the generated development view. This allows the creation of a machining program in which the plating removal region is set without the user having to manually specify the region where the plating layer is to be removed, thereby improving work efficiency.

[0087] In particular, in the past, users could not specify the area where the plating layer was to be removed unless they imagined the three-dimensional shape of the product from a development view and calculated coordinates taking into account the positions of other related parts. However, the machining program creation method according to the second embodiment identifies the edge portions of the product to be welded based on 3D CAD data, and sets the plating removal area adjacent to multiple cut surfaces joined by the welded edge portions. Therefore, a machining program with the area where the plating layer is to be removed can be created without the user having to perform tedious work, thereby improving work efficiency.

[0088] Furthermore, in the method for creating a machining program according to the second embodiment, the plating removal regions include a cut portion plating removal region 152 that is set to prevent metal components of the molten plating layer from flowing into the cut surface when the sheet metal is cut, and a joint portion plating removal region 153 that is set in the surface portion of the sheet metal where the cut surfaces of the sheet metal are joined. The cut portion plating removal region 152 and the joint portion plating removal region 153 are set based on the joining state of multiple sheet metals joined at the weld edge. This makes it possible to easily create a machining program that can prevent metal components of the plating layer from flowing into the cut surface and also remove the plating layer from the portion where the cut surfaces of the sheet metal are joined.

[0089] Although the embodiments of the present disclosure have been described above, the descriptions and drawings that form part of this disclosure should not be understood to limit this disclosure. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure.

[0090] The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2024-178839, filed October 11, 2024, the entire disclosure of which is incorporated herein by reference.

Claims

1. A method for welding sheet metal, comprising: acquiring a processing program for cutting out a metal sheet from a base material having a plating layer formed thereon and welding the metal sheet; acquiring a cutting position for cutting the metal sheet from the acquired processing program; identifying a welding cutting position which is a cutting position for welding from among the acquired cutting positions; setting an irradiation area onto which a laser beam is irradiated from a laser processing machine on both sides of the identified welding cutting position; irradiating the set irradiation area with a laser beam to remove the plating layer; irradiating the cutting position with a laser beam to cut out the metal sheet from the base material; and welding the cut-out metal sheet.

2. The sheet metal welding method according to claim 1, wherein the irradiation area is set to a predetermined width on both sides of the weld cut position.

3. The method for welding sheet metal according to claim 1, further comprising the steps of: acquiring from the processing program a welding range in which welding is performed on the surface of the sheet metal adjacent to the weld cut position; setting the irradiation area in the acquired welding range; and setting the irradiation area of ​​a predetermined width on the opposite side of the welding range from the weld cut position.

4. The sheet metal welding method according to claim 2 or 3, wherein the predetermined width is set to be equal to or greater than the beam diameter of the laser beam during laser cutting.

5. A method for welding sheet metal according to any one of claims 1 to 3, in which the plating layer is removed by vibrating the laser beam with a predetermined vibration amplitude and vibrating the beam spot formed on the surface of the sheet metal in a direction perpendicular to the traveling direction of the laser beam.

6. A method for welding sheet metal according to any one of claims 1 to 3, in which the plating layer is removed by vibrating the laser beam with a predetermined vibration amplitude and vibrating the beam spot formed on the surface of the sheet metal in a semicircular manner in the direction of travel of the laser beam.

7. The method for welding sheet metal according to claim 3, further comprising the steps of: irradiating the laser beam onto the irradiation area set in the welding area to remove the plating layer; forming protrusions around the welding area with metal components of the removed plating layer; and aligning the sheet metal with the formed protrusions to weld the sheet metal.

8. A method for creating a processing program, comprising: acquiring design data for a product formed from a metal sheet cut out from a base material on which a plating layer is formed; identifying a welding edge portion to be welded from among edge portions of the product based on the design data; setting a plating removal area for removing the plating layer adjacent to cut surfaces of a plurality of the metal sheets joined at the identified welding edge portion; generating an unfolded view of the metal sheet in which the plating removal area is set; and creating a processing program for cutting out the metal sheet from the base material and welding it based on the generated unfolded view.

9. A method for creating a processing program as described in claim 8, wherein the plating removal area includes a cut portion plating removal area that is set so that the metal components of the molten plating layer do not flow into the cut surface when the sheet metal is cut out, and a joint portion plating removal area that is set on the surface portion of the sheet metal where the cut surface of the sheet metal is joined, and the cut portion plating removal area and the joint portion plating removal area are set based on the joining state of the multiple sheets of metal joined at the welding edge portion.

10. A processing program creation device that acquires design data of a product formed from sheet metal cut out from a base material on which a plating layer is formed, identifies a welding edge portion to be welded from among edge portions of the product based on the design data, sets a plating removal area in contact with cut surfaces of multiple sheet metals joined at the identified welding edge portion, removes the plating layer, generates an expansion drawing of the sheet metal in which the plating removal area is set, and creates a processing program for cutting out the sheet metal from the base material and welding it based on the generated expansion drawing.

11. The processing program creation device described in claim 10, wherein the plating removal area includes a cut portion plating removal area that is set so that the metal components of the plating layer that melts when the sheet metal is cut do not flow into the cut surface, and a joint portion plating removal area that is set on the surface portion of the sheet metal where the cut surface of the sheet metal is joined, and the cut portion plating removal area and the joint portion plating removal area are set based on the joining state of the multiple pieces of sheet metal joined at the welding edge portion.

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