Laser-arc hybrid welding equipment

Abstract

To improve welding allowance while removing a surface film in a portion to be bonded.SOLUTION: A laser / arc hybrid welding device 1 includes a laser torch 40 and a welding torch 10. The laser torch 40 emits laser 50 to a portion to be bonded 3 to remove a surface film of the portion to be bonded 3. The welding torch 10 generates an arc 25 in between the welding torch 10 and the portion to be bonded 3 to weld the portion to be bonded 3. The welding torch 10 is configured such that a polarity ratio of an electrode positive polarity and an electrode negative polarity can be changed. After the laser torch 40 emits the laser 50 to the portion to be bonded 3, when the polarity ratio of the electrode negative polarity in the welding torch 10 is equal to or greater than 50%, the portion to be bonded 3 is welded.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laser-arc hybrid welding device. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2021-49562 (Patent Document 1) is a prior art document disclosing a laser-arc hybrid welding device. The laser-arc hybrid welding device described in Patent Document 1 includes a laser torch and a welding torch. The laser torch is configured to irradiate a laser toward a joint. The welding torch is configured to generate an arc between the joint and the laser torch. The joint is welded by heat input from the laser irradiation and arc welding, ensuring the joint strength of the joint. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-49562 Summary of the Invention [Problem to be solved by the invention]

[0004] In consumable electrode arc welding, welding is performed by appropriately changing the polarity ratio of the positive electrode and the negative electrode. In the laser-arc hybrid welding device described in Patent Document 1, increasing the polarity ratio of the negative electrode in arc welding increases the amount of melted welding wire, thereby improving the welding workability. On the other hand, increasing the polarity ratio of the negative electrode decreases the polarity ratio of the positive electrode, which may result in insufficient removal of the surface coating of the joint.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a laser-arc hybrid welding device that can remove the surface coating of the part to be joined while improving the welding workability. [Means for solving the problem]

[0006] The laser-arc hybrid welding device according to the present invention includes a laser torch and a welding torch. The laser torch irradiates the parts to be welded with a laser to remove the surface coating of the parts to be welded. The welding torch generates an arc between the parts to be welded and the welding torch to weld the parts to be welded. The welding torch is configured to be able to change the polarity ratio of the positive electrode polarity and the negative electrode polarity. After the parts to be welded are irradiated with a laser by the laser torch, the parts to be welded are welded with a polarity ratio of the negative electrode polarity of the welding torch of 50% or more.

[0007] In this case, the removal of the surface coating of the welded part is ensured by irradiating the laser, while the polarity ratio of the electrode negative polarity in the arc welding is set to 50% or more, thereby increasing the amount of melted welding wire and improving the welding workability.

[0008] In one embodiment of the present invention, the laser output of the laser torch increases as the polarity ratio of the electrode negative polarity increases.

[0009] In this case, the removal effect of the surface coating, which decreases as the polarity ratio of the electrode positive polarity decreases, can be ensured by increasing the laser output.

[0010] In one embodiment of the present invention, the width of the laser irradiation area in the direction perpendicular to the welding direction increases as the polarity ratio of the electrode negative polarity increases.

[0011] This increases the width of the surface coating removed by laser irradiation, thereby suppressing humping in arc welding.

[0012] In one embodiment of the present invention, the width of the laser irradiation area in a direction perpendicular to the welding direction is equal to or greater than one time and equal to or less than two times the leg length of the parts to be welded.

[0013] In this case, by irradiating the laser with an appropriate width, it is possible to ensure that the surface coating can be removed by irradiating the laser.

[0014] In one embodiment of the present invention, the welding torch welds the parts to be joined with a polarity ratio of electrode negative polarity of 70% or more. The welding by the welding torch is short-circuit welding.

[0015] In this case, the generation of spatter can be suppressed by short-circuit welding while ensuring the removal of the surface coating and the welding work margin. [Effects of the Invention]

[0016] According to the present invention, it is possible to improve the welding workability while removing the surface coating of the parts to be welded. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing the configuration of a laser-arc hybrid welding apparatus according to one embodiment of the present invention. [Figure 2] 1 is a top view showing a state in which a base material is being welded by a laser-arc hybrid welding apparatus according to an embodiment of the present invention. FIG. [Figure 3] 1 is a cross-sectional view showing the laser irradiation range and arc welding range of a base material in a laser-arc hybrid welding device according to an embodiment of the present invention. FIG. [Figure 4] 1 is a cross-sectional view showing the joining state of base materials welded by a laser-arc hybrid welding device according to one embodiment of the present invention. FIG. [Figure 5] 1 is a graph showing the relationship between the polarity ratio of electrode negative polarity in arc welding and laser output in a laser-arc hybrid welding device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] A laser-arc hybrid welding apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In the following description of the embodiment, the same or corresponding parts in the drawings will be given the same reference numerals, and the description thereof will not be repeated.

[0019] In the drawings, the welding direction is designated as the DR1 direction, and the direction perpendicular to the welding direction and parallel to the base metal surface is designated as the DR2 direction.

[0020] In addition, electrode positive polarity refers to a polarity state in which the welding torch side of the current path supplied from the welding power source is the anode and the base metal side is the cathode. Electrode negative polarity refers to a polarity state in which the base metal side of the current path supplied from the welding power source is the anode and the welding torch side is the cathode. The above-mentioned electrode positive polarity is sometimes referred to as EP polarity, and electrode negative polarity is sometimes referred to as EN polarity. Furthermore, the polarity ratio of the electrode positive polarity to the total polarity time of the electrode positive polarity and the electrode negative polarity is sometimes referred to as EP ratio, and the polarity ratio of the electrode negative polarity is sometimes referred to as EN ratio.

[0021] FIG. 1 is a schematic diagram showing the configuration of a laser-arc hybrid welding apparatus according to an embodiment of the present invention.

[0022] As shown in FIG. 1, a laser-arc hybrid welding apparatus 1 according to one embodiment of the present invention includes a welding torch 10, a welding power supply 30, a laser torch 40, and a laser oscillator 60.

[0023] The laser-arc hybrid welding device 1 is used to join metals together. By using the laser-arc hybrid welding device 1, one and the other of the base materials 2 to be joined are joined at the joint 3 by a lap fillet weld joint, a flare weld joint, or the like.

[0024] The base material 2 is made of, for example, aluminum or magnesium, or an alloy thereof. It is preferable that the melting point of the surface coating, such as an oxide coating, formed on the surface of the base material 2 is higher than the melting point of the base material 2 itself, and that there is a large temperature difference between the melting points of the base material and the surface coating. The base material 2 may also be made of iron or titanium, or an alloy thereof.

[0025] Welding torch 10 and welding power supply 30 are devices for performing arc welding. Welding torch 10 supplies welding wire 20 and a shielding gas (not shown) toward base material 2. Welding torch 10 generates an arc 25 between itself and parts to be joined 3 to weld the parts to be joined 3. Specifically, welding torch 10 receives a supply of welding current from welding power supply 30, generates arc 25 between the tip of welding wire 20 and base material 2, and supplies a shielding gas such as argon gas or carbon dioxide gas toward base material 2, thereby welding parts to be joined 3.

[0026] Welding power supply 30 generates a welding voltage and a welding current for performing arc welding, and outputs the generated welding voltage and welding current to welding torch 10. Welding power supply 30 also controls the feed speed of welding wire 20 in welding torch 10.

[0027] The welding torch 10 can weld the base material 2 under welding conditions of electrode positive polarity (EP polarity) and electrode negative polarity (EN polarity).

[0028] In EP polarity arc welding, the base material 2 becomes the cathode of the welding current, and cathode spots that are the origins of electron emission are concentrated on the base material 2, thereby removing the surface coating of the base material 2. For this reason, EP polarity arc welding is suitable for welding materials that form oxide coatings with melting points that are relatively higher than the melting point of the base material 2 itself.

[0029] In EN polarity arc welding, the welding torch 10 becomes the cathode of the welding current, causing cathode spots to concentrate on the welding wire 20, increasing the amount of melting of the welding wire 20. For this reason, EN polarity arc welding is suitable for welding thin plates because it does not excessively melt the base material when the base material is thin. Furthermore, in EN polarity arc welding, when there is a gap between one side and the other side of the base material, the welding wire 20 fills the gap, improving the gap tolerance for filling the gap during welding. In other words, EN polarity arc welding has a high welding workability.

[0030] The welding torch 10 is configured to be able to change the polarity ratio (EP ratio and EN ratio) of the electrode positive polarity and the electrode negative polarity. The EP ratio and EN ratio can be set as desired by inverter control. When AC arc welding is performed, welding is performed while alternating between EP polarity and EN polarity at a polarity ratio set as desired by inverter control.

[0031] When the EN ratio is increased, the EP ratio decreases as the EN ratio increases, which reduces the effectiveness of removing the surface coating and may result in arc welding being performed without the surface coating being removed. In this case, humping is more likely to occur in arc welding, which may make arc welding difficult. For this reason, in arc welding of base metals such as aluminum or magnesium, it is desirable to maintain the EP ratio at a certain ratio or higher in order to remove the surface coating, which has a melting point higher than that of the base metal. In arc welding of base metals such as aluminum or magnesium, welding is performed, for example, with an EN ratio of 20% to 30%.

[0032] The laser torch 40 irradiates the laser 50 toward the parts to be joined 3, thereby removing the surface coating of the parts to be joined 3. The laser torch 40 and the laser oscillator 60 are devices for performing welding using the laser 50. The laser torch 40 receives a supply of laser light from the laser oscillator 60, and irradiates the parts to be joined 3 of the base material 2 with the laser 50, thereby removing the surface coating of the parts to be joined 3.

[0033] In the present embodiment, there is no limitation on the method of irradiating the laser 50 onto the parts to be joined 3. For example, the method of irradiating the laser 50 onto the parts to be joined 3 may be to diffract the laser 50 using a diffractive optical element and focus the light, or to irradiate the laser 50 by driving a mirror with a motor inside the laser torch 40 to scan the laser 50, or to irradiate the laser 50 by defocusing the laser 50.

[0034] The irradiation of the laser 50 may not only remove the surface coating of the base material 2, but may also melt the base material 2 together with the arc welding. In particular, when the EN ratio of the arc welding in the laser-arc hybrid welding device 1 is increased, the welding wire 20 melts more easily than the base material 2, and therefore the base material 2 can be melted by the irradiation of the laser 50, thereby ensuring the amount of melting of the base material 2.

[0035] Fig. 2 is a top view showing a state in which base materials are welded by a laser-arc hybrid welding apparatus according to an embodiment of the present invention. Fig. 3 is a cross-sectional view showing a laser irradiation range and an arc welding range on a base material by a laser-arc hybrid welding apparatus according to an embodiment of the present invention. Fig. 4 is a cross-sectional view showing a joined state of base materials welded by a laser-arc hybrid welding apparatus according to an embodiment of the present invention. Note that, for ease of understanding, the welding wire 20, the arc 25, and the laser 50 are not shown in Fig. 2.

[0036] 2 to 4, the base material 2 is made up of a first base material 4 and a second base material 5. A gap G is provided between the first base material 4 and the second base material 5. The first base material 4 and the second base material 5 are welded by an arc 25 and irradiated with a laser 50 along the welding advance direction (DR1 direction) to join the first base material 4 and the second base material 5 to each other at the joined portion 3.

[0037] The laser 50 is irradiated within a range of an irradiation region 70. The irradiation region 70 of the laser 50 has a width W in a direction (DR2 direction) perpendicular to the welding progress direction. The width W of the irradiation region 70 of the laser 50 in the direction (DR2 direction) perpendicular to the welding progress direction is at least one time and at most two times the leg length L of the portion to be welded 3. As the laser 50 is irradiated within the range of the irradiation region 70 and progresses in the DR1 direction, a laser mark 71 is formed behind the irradiation region 70.

[0038] After the laser torch 40 irradiates the workpiece 3 with a laser 50, the workpiece 3 is welded with a welding torch 10 having a negative electrode polarity ratio (EN ratio) of 50% or more. The arc 25 melts the first base material 4 and the second base material 5. As a result, the workpiece 3 is welded while forming a molten pool 90 along the DR1 direction.

[0039] The width W of the irradiation area 70 of the laser 50 in the direction perpendicular to the welding direction (DR2 direction) increases as the polarity ratio of the electrode negative polarity (EN ratio) increases. Thus, by gradually increasing the width W of the irradiation area 70 of the laser 50 in conjunction with the EN ratio, the range of the surface coating removed by irradiation with the laser 50 is widened, and even if the surface coating removal effect of arc welding decreases due to a decrease in the EP ratio, it is possible to perform arc welding while suppressing the influence of the surface coating.

[0040] FIG. 5 is a graph showing the relationship between the polarity ratio of the electrode negative polarity in arc welding and the laser output in a laser-arc hybrid welding device according to an embodiment of the present invention.

[0041] As shown in Fig. 5, the output of the laser 50 of the laser torch 40 increases as the polarity ratio of the electrode negative polarity (EN ratio) increases. In this embodiment, the output of the laser 50 is, for example, 0.5 kW when the EN ratio is 50%. The output of the laser 50 increases in proportion to the EN ratio, and is, for example, 2.0 kW when the EN ratio is 100%. As a result, the removal effect of the surface coating of the base material 2 by the laser 50 becomes stronger as the EN ratio increases. Note that the required output of the laser 50 differs depending on the laser profile of the laser 50, the welding speed, the thickness of the base material, and the joint shape, and is therefore not limited to the output of the laser 50 shown in Fig. 5.

[0042] Here, the results of a test in which laser-arc hybrid welding was performed on a base material using the laser-arc hybrid welding apparatus 1 of this embodiment will be described.

[0043] The first and second base materials were lap fillet joints made of aluminum alloy with a plate thickness of 2 mm. There was a 1 mm gap between the first and second base materials. EN polarity arc welding was performed at a welding speed of 1 m / min, a welding current of 100 A, and a wire feed speed of 6 m / min. As a result, the base materials did not melt, resulting in humping.

[0044] Next, prior to the above arc welding, laser-arc hybrid welding was performed, in which a laser with an average output of 1.0 kW was irradiated. As a result, no humping occurred during welding, and the first and second base materials were well joined at the welded portions. With EP polarity arc welding, the first and second base materials could not be joined to each other at the welded portions, and good welding results could not be obtained. This confirmed that laser-arc hybrid welding under the conditions of this embodiment can well join the first and second aluminum alloy base materials with a gap.

[0045] In a laser-arc hybrid welding apparatus 1 according to one embodiment of the present invention, after the laser torch 40 irradiates the workpiece 3 with a laser 50, the workpiece 3 is welded with a polarity ratio (EN ratio) of the electrode negative polarity in the welding torch 10 of 50% or more, thereby increasing the amount of melting of the welding wire 20. Therefore, the irradiation of the laser 50 can ensure the removal of the surface coating of the workpiece 3, while improving the welding work tolerance.

[0046] In a laser-arc hybrid welding apparatus 1 according to one embodiment of the present invention, the output of the laser 50 of the laser torch 40 is increased as the polarity ratio of the electrode negative polarity (EN ratio) increases, thereby ensuring the removal effect of the surface coating, which decreases as the polarity ratio of the electrode positive polarity (EP ratio) decreases.

[0047] In a laser-arc hybrid welding apparatus 1 according to one embodiment of the present invention, the width W of the irradiation area of ​​the laser 50 in the direction perpendicular to the welding direction (DR2 direction) is increased as the polarity ratio of the electrode negative polarity (EN ratio) increases, thereby removing the surface coating irradiated by the laser 50 to a sufficient extent and suppressing humping in the arc welding.

[0048] In a laser-arc hybrid welding apparatus 1 according to one embodiment of the present invention, the width W of the irradiation area 70 of the laser 50 in the direction perpendicular to the welding direction (DR2 direction) is between 1 and 2 times the leg length L of the part to be joined 3, and by irradiating the laser 50 with an appropriate width W, the removal effect of the surface coating by irradiation with the laser 50 can be ensured.

[0049] A laser-arc hybrid welding apparatus according to a modification of an embodiment of the present invention will be described below. The laser-arc hybrid welding apparatus according to this modification has welding conditions for the welding torch that are different from those of the laser-arc hybrid welding apparatus 1 according to an embodiment of the present invention, and therefore, description of the same configuration as that of the laser-arc hybrid welding apparatus 1 according to an embodiment of the present invention will not be repeated.

[0050] A welding torch according to a modified example of an embodiment of the present invention welds a joint with a negative electrode polarity ratio (EN ratio) of 70% or more. If the EN ratio exceeds 70%, cathode spots in arc welding are generated at the tip and side of the welding wire, making droplet formation unstable when the welding wire melts. If the arc welding is pulse welding, the pulse current cycle becomes unstable, which may cause unstable welding and spatter.

[0051] The welding performed by the welding torch in this modification is short-circuit welding, which allows welding while bringing droplets of the welding wire into contact with the welding wire and the base material, thereby making it possible to prevent spatter from occurring during welding, as compared to pulse welding.

[0052] In a laser-arc hybrid welding device according to a modified embodiment of the present invention, the parts to be joined are welded with a polarity ratio (EN ratio) of the electrode negative polarity of the welding torch of 70% or more, and the welding torch is short-circuit welding, so that the removal of the surface coating and the welding work margin can be ensured while the generation of spatter can be suppressed by short-circuit welding.

[0053] It should be noted that the above-described embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments. Furthermore, all modifications within the scope and meaning equivalent to the claims are included. In the description of the above-described embodiments, combinable configurations may be combined with each other. [Explanation of symbols]

[0054] 1 Laser-arc hybrid welding device, 3 Workpiece, 10 Welding torch, 25 Arc, 40 Laser torch, 50 Laser, 70 Irradiation area, L Leg length, W Width.

Claims

1. a laser torch that irradiates a laser toward a portion to be joined and removes a surface coating of the portion to be joined; a welding torch that generates an arc between the welding torch and the welding parts to weld the welding parts, the welding torch is configured to be able to change the polarity ratio of the electrode positive polarity and the electrode negative polarity, a laser-arc hybrid welding device that irradiates the laser to the portion to be welded with the laser by the laser torch, and then welds the portion to be welded with the polarity ratio of the electrode negative polarity in the welding torch being 50% or more.

2. 2. The laser-arc hybrid welding device according to claim 1, wherein the output of the laser of the laser torch increases as the polarity ratio of the electrode negative polarity increases.

3. 3. The laser-arc hybrid welding device according to claim 1, wherein the width of the laser irradiation area in the direction perpendicular to the welding direction increases as the polarity ratio of the electrode negative polarity increases.

4. 4. The laser-arc hybrid welding device according to claim 3, wherein the width of the laser irradiation area in a direction perpendicular to the welding direction is equal to or greater than one time and equal to or less than two times the leg length of the welded parts.

5. the welding torch welds the joint portion with the polarity ratio of the electrode negative polarity being 70% or more, 5. The laser-arc hybrid welding device according to claim 1, wherein the welding torch performs short-circuit welding.

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