A multi-wire additive manufacturing device and control method based on cross-coupled arcs

Abstract

The present invention discloses a multi-wire additive manufacturing device and a control method based on cross-coupled arcs, including a special multi-wire additive welding torch, a substrate, a gas cylinder, a first gas metal arc welding power source, a second gas metal arc welding power source, a first wire feeding mechanism, a second wire feeding mechanism, a third wire feeding mechanism, and a fourth wire feeding mechanism. The device forms two cross-shaped welding circuits by using two gas metal arc welding power sources, four wire feeders, and a special welding torch. The magnetic fields generated by two perpendicular currents act on the arcs, causing specific arc-wrapping behaviors of the arcs. The arcs wrap around the electrodes, generating a U-shaped arc formed by the overlap and coupling of two C-shaped arcs. The heat generated by the U-shaped arc is mainly used to melt the wire materials, and the gravity and the arc force along the gravity direction are used for droplet transfer, realizing the decoupling of heat-mass-force during the additive process, reducing the heat input to the already formed deposited layer during the additive process, preventing the occurrence of remelting defects in the deposited layer, and improving the utilization rate of the heat source.

Description

Technical Field

[0001] The present invention relates to a multi-wire additive manufacturing device based on a cross-coupled arc and a multi-wire rotating arc melting control method, belonging to the fields of arc additive manufacturing and in-situ alloy manufacturing of multi-element metals. Background Art

[0002] Additive manufacturing technology is a new manufacturing technology developed in the late 1980s. Additive manufacturing converts a digital model into a three-dimensional entity by "discretizing and stacking" materials. Among them, arc additive manufacturing technology has attracted the attention of domestic and foreign research scholars due to its high melting efficiency and low cost. At present, the arc wire additive technology at home and abroad is mostly a simple transplantation of arc surfacing to additive manufacturing. During the additive process, high-temperature liquid metal droplets are continuously and smoothly transferred to the surface of the formed part and accumulated layer by layer. With the increase in the number of metal stacking layers, the gradually increasing heat accumulation and gradually deteriorating heat dissipation conditions make it more difficult to control the molten pool morphology and forming size. Due to the application background of "transporting heat and mass on a base material (substrate) with good heat dissipation to obtain metallurgical bonding", there is a high degree of coupling between heat transfer and mass transfer in the traditional welding arc heat source, and the impact of the thermal force on the molten pool increases gradually with the increase in the height of metal stacking. At present, there have emerged various new and efficient forms of composite heat source action, such as Tandem welding heat source, T.I.M.E. welding heat source, multi-wire coupled heat source, etc. However, when these multi-electrode heat sources are welding, multiple arcs are ignited in parallel with the workpiece, and the heat-mass-force of multiple arcs during the welding process is a carrier of mutual coupling.

[0003] To address the above technical problems, the present invention provides a multi-wire rotating arc additive manufacturing device and control method based on cross-coupled arcs, which realizes high-efficiency additive manufacturing process and decoupling of heat, mass, and force during the additive manufacturing process, reduces heat input to the already deposited part during the additive manufacturing process, and improves the utilization efficiency of the welding heat source. At the same time, it makes the efficiencies of the four melting poles of the cross-coupled arcs controllable during the additive manufacturing process, realizes stable transition of the arc polarity and reasonable distribution of heat generation in the arc pole regions, and achieves stable arc additive manufacturing. The present invention uses two gas metal arc welding power sources, four wire feeders, and a special welding torch to form two cross-shaped welding circuits. The magnetic fields generated by two perpendicular currents act on the arcs, causing specific arc-wrapping behaviors. The arcs wrap around the electrodes, generating a U-shaped arc formed by the overlap and coupling of two C-shaped arcs. The heat generated by the U-shaped arc is mainly used to melt the wire. Gravity and the arc force along the direction of gravity are used for droplet transfer, realizing decoupling of heat, mass, and force during the additive process, reducing heat input to the already formed deposited layer during the additive process, preventing remelting defects in the deposited layer, and improving the heat source utilization rate. At the same time, for cross-coupled arc additive manufacturing, due to the cathode region effect, the melting efficiencies of the welding wires are different at the anode and cathode, and the arc may become unstable or even extinguish. To address this, the present invention changes the positions of the four contact tips in the welding torch and the wire feeding methods of the wire feeders, increasing the stable existence range and adjustable range of the cross-coupled arcs. At the same time, by applying an alternating current with variable polarity to the two gas metal arc welding power sources, the U-shaped arc formed by the cross-coupled arcs alternately switches the arc polarity along the arc-wrapping direction of the coupled arcs, macroscopically showing that the entire arc rotates in the same direction. The droplets formed by the melting of the wire also stably transition towards the rotation center along the direction of the rotating arc, solving the problem of different melting efficiencies due to the pole region effect, realizing controllable efficiencies of the four melting poles, and thus realizing stable transition of the arc polarity and reasonable distribution of heat generation in the arc pole regions. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a multi-wire rotating arc additive manufacturing device and control method based on cross-coupled arcs, which realizes high-efficiency additive manufacturing process and decoupling of heat, mass, and force during the additive manufacturing process, reduces heat input to the already deposited part during the additive manufacturing process, and improves the utilization efficiency of the welding heat source. At the same time, it makes the efficiencies of the four melting poles of the cross-coupled arcs controllable during the additive manufacturing process, realizes stable transition of the arc polarity and reasonable distribution of heat generation in the arc pole regions, and achieves stable arc additive manufacturing.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A multi-wire rotating arc additive manufacturing device based on cross-coupled arcs, comprising a special multi-wire additive welding torch (5), a substrate (9), a gas cylinder (2), a first gas metal arc welding power source (3), a second gas metal arc welding power source (7), a first wire feeder (1), a second wire feeder (4), a third wire feeder (6), and a fourth wire feeder (8);

[0007] The special multi-wire additive welding torch (5) includes a first wire guide tube (5-1), a second wire guide tube (5-2), a third wire guide tube (5-3), a fourth wire guide tube (5-4), a shielding gas inlet pipe (5-5), an insulating wood (5-6), a gas sieve (5-7), a ceramic nozzle (5-8), a contact tip (5-9), and a high-temperature ceramic wire guide sleeve (5-10).

[0008] The first wire feeder (1), the second wire feeder (4), the third wire feeder (6), and the fourth wire feeder (8) are respectively installed in the first wire guide tube (5-1), the second wire guide tube (5-2), the third wire guide tube (5-3), and the fourth wire guide tube (5-4) of the special multi-wire additive welding torch (5), and the special multi-wire additive welding torch (5) faces the substrate (9). The gas cylinder (2) is installed in the shielding gas inlet pipe (5-5) of the special multi-wire additive welding torch (5). The first gas metal arc welding (3) is respectively connected to the wire guide tubes of the second wire feeder (4) and the third wire feeder (6). The second gas metal arc welding power source (7) is respectively connected to the wire guide tubes of the first wire feeding mechanism (1) and the fourth wire feeder (8);

[0009] The special multi-wire additive welding torch (5) uses an axial gas inlet method to reduce the overall volume of the special multi-wire additive welding torch. The insulating wood (5-6) is connected to the first wire guide tube (5-1), the second wire guide tube (5-2), the third wire guide tube (5-3), the fourth wire guide tube (5-4), and the contact tip (5-9) through openings, playing the role of insulation and high-temperature resistance. The gas sieve (5-7) is a small hole provided on the insulating wood, and its purpose is to improve the protection effect on the special multi-wire additive welding torch (5) and reduce the turbulence degree of the shielding gas entering the ceramic nozzle (5-8). The ceramic nozzle (5-8) is arranged at the end of the special multi-wire additive welding torch (5) and is bolted to the main body of the special multi-wire additive welding torch (5). The purpose of using the ceramic nozzle (5-8) is not to short-circuit with the workpiece on the substrate (9) and to be high-temperature resistant, to keep the gas flow uniform and stable during the additive process, and to have good gas flow rate and arc stiffness; the contact tip (5-9) is arranged inside the ceramic nozzle (5-8), and a high-temperature ceramic wire guide sleeve (5-10) is arranged circumferentially on the contact tip (5-9). The high-temperature ceramic wire guide sleeve (5-10) can increase and restrict the dry elongation of the welding wire and preheat the welding wire, and at the same time it can also prevent the contact tip (5-9) from back burning. The angles of the openings of the insulating wood (5-6) and the first wire guide tube (5-1), the second wire guide tube (5-2), the third wire guide tube (5-3), and the fourth wire guide tube (5-4) can be adjusted synchronously. The four wire guide tubes change angles synchronously, and the angle changes from the wire guide tube being perpendicular to the horizontal plane to 60 degrees.

[0010] The positive and negative electrodes of the first gas metal arc welding power source (3) are respectively connected to the wire materials on the first wire feeder (1) and the third wire feeder (6), and the first wire guide tube (5-1) and the third wire guide tube (5-3) to form a first welding circuit; the positive and negative electrodes of the second gas metal arc welding power source (7) are respectively connected to the wire materials on the second wire feeder (4) and the fourth wire feeder (8), and the second wire guide tube (5-2) and the fourth wire guide tube (5-4) to form a second welding circuit; the two welding circuits form a cross-shaped intersecting arc at the end of the special multi-wire additive welding torch (5). When the magnetic fields generated by two perpendicular currents act on the cross-shaped intersecting arc, the cross-shaped intersecting arc shows an arc-wrapping behavior, and the cross-shaped intersecting arc wraps around the electrode, generating a U-shaped arc formed by the overlap and coupling of two C-shaped arcs. The heat generated by the U-shaped arc is mainly used to melt the wire material, and the gravity and the arc force along the gravity direction are used for droplet transfer, realizing the decoupling of heat-mass-force in the additive process, reducing the heat input to the already formed deposition layer during the additive process, preventing the deposition layer from generating remelting defects, and at the same time improving the heat source utilization rate.

[0011] Furthermore, the first gas metal arc welding power source (3) and the second gas metal arc welding power source (7) adopt variable polarity AC power sources. The output waveforms of the two AC power sources are the same. The initial waveform of the first gas metal arc welding generated by the first gas metal arc welding power source (3) is 1 / 4 cycle faster than the second gas metal arc welding generated by the second gas metal arc welding power source (7), ensuring that the U-shaped arc formed by the cross-coupled arc alternately switches the arc polarity along the arc-wrapping direction of the coupled arc, and the macroscopic manifestation is that the overall arc rotates in the same direction. The droplets formed by the melting of the welding wire also stably transition to the rotation center along the direction of the rotating arc, solving the problem of different melting efficiencies due to the pole region effect, realizing the controllable efficiency of the four melting poles, and further realizing the stable transition of the arc polarity and the reasonable distribution of the heat generation in the arc pole region.

[0012] Further, the wire in the first wire feeder (1) is introduced into the corresponding contact tip (5-9) through the first wire guide tube (5-1) on the welding torch, the wire in the second wire feeder (4) is introduced into the corresponding contact tip (5-9) through the second wire guide tube (5-2) on the welding torch, the wire in the third wire feeder (6) is introduced into the corresponding contact tip (5-9) through the third wire guide tube (5-3) on the welding torch, and the wire in the fourth wire feeder (8) is introduced into the corresponding contact tip (5-9) through the fourth wire guide tube (5-4) on the welding torch. The first wire feeder, the second wire feeder, the third wire feeder, and the fourth wire feeder are independent of each other, and the two gas metal arc welding power sources corresponding to the wire feeders are also independent of each other and are adjusted independently. Among them, the first wire feeder and the second wire feeder adopt the constant wire feeding method to adjust their respective wire feeding speeds respectively, and the third wire feeder and the fourth wire feeder adopt the arc voltage feedback variable wire feeding method to adjust their respective wire feeding speeds respectively, preventing the generated arc from being disordered or even extinguished. At the same time, this wire feeding speed control method can well avoid the problems of the cathode region effect of multi-wire additive manufacturing and different melting efficiencies of the four-terminal welding wires, enabling the rotary arc and droplet transfer to proceed stably.

[0013] The wire materials used are all metals, such as aluminum alloy, magnesium alloy, and carbon steel. The four wire feeders can feed the same wire material to manufacture a formed part that meets the requirements, or they can feed heterogeneous wire materials to manufacture high-strength alloys, solving the problem of the great difficulty in preparing special wire materials for high-strength alloy additive manufacturing.

[0014] In the special welding torch, the four wire guide tubes are arranged in a circumferential pattern at equal angles, and the extension lines of the contact tips are arranged in a cross shape, increasing the arc stability range of the multi-wire rotary arc and reducing the occurrence of arc extinction and arc annihilation.

[0015] The gas cylinder inlet pipe is connected to the gas inlet in the special welding torch, and the gas used in the gas cylinder is an inert gas.

[0016] A control method for a multi-wire rotary arc additive manufacturing device based on a cross-coupled arc, characterized by comprising the following steps:

[0017] Step 1: Pretreat the surface of the workpiece to be deposited before cladding, and fix the pretreated workpiece on the substrate (9).

[0018] Step 2: Connect the multi-wire rotary arc additive manufacturing device based on the cross-coupled arc, and select appropriate current waveforms, wire feeding speeds, etc. according to the deposited layer.

[0019] Step 3: Start the first gas metal arc welding power source and the second gas metal arc welding power source at the same time, then start the four wire feeders, and perform additive stacking according to the planned path. When the welding torch moves to the end point of the deposited layer, turn off the four wire feeders, the first and second gas metal arc welding power sources in sequence, and then pass the shielding gas for 5 s to prevent the deposited layer from oxidizing.

[0020] Step 4: After the deposited layer cools for 40 - 90 s, raise the height of the welding torch.

[0021] Step 5: Repeat Steps 1 - 4 in a cycle for deposition, and finally form the required component.

[0022] Advantages of the present invention:

[0023] (1) Compared with the existing inventions, the present invention forms two cross - shaped welding arcs by using two gas metal arc welding power sources, four wire feeders and a special welding torch. When the magnetic fields generated by two perpendicular currents act on the arcs, the arcs exhibit specific arc - winding behaviors, generating a U - shaped arc formed by the overlap and coupling of two C - shaped arcs. The welding power source is not connected to the substrate to form a circuit, reducing the heat input to the deposited part during the additive process.

[0024] (2) Compared with the existing inventions, the present invention manufactures a special welding torch for multi - wire rotary arc additive manufacturing based on cross - coupled arcs. The welding torch and other devices of the present invention form a multi - wire additive device based on cross - coupled arcs, and the four - wire welding torch improves the additive deposition efficiency.

[0025] (3) Compared with the existing inventions, the present invention changes the arrangement of the contact tips in the special welding torch and the wire feeding methods of the four wire feeders, increasing the stable existence range and adjustable range of the cross - coupled arcs, and improving the stability of the additive process.

[0026] (4) Compared with the existing inventions, the four wire feeders of the present invention can feed wire materials of different materials to manufacture the required high - strength alloy, solving the problem of the great difficulty in preparing special wire materials for high - strength alloy additive manufacturing.

[0027] (5) Compared with the existing inventions, the present invention applies an alternating current with variable polarity to the two gas metal arc welding power sources, causing the U - shaped arc formed by the cross - coupled arcs to alternately switch the arc polarity along the arc - winding direction of the coupled arcs. Macroscopically, it is manifested as the overall rotation of the arc in the same direction. The molten droplets formed by the melting of the welding wire also stably transition to the rotation center along the direction of the rotating arc, solving the problem of different melting efficiencies due to the pole - region effect, realizing the controllable efficiency of the four melting poles, and further realizing the stable transition of the arc polarity and the reasonable distribution of heat generation in the arc pole region. Description of the Drawings

[0028] Figure 1 It is a diagram of a multi - wire rotary arc additive manufacturing device based on cross - coupled arcs.

[0029] Figure 2 It is a structural diagram of the special welding torch. a is the elevation view of the special welding torch; b is the front view of the special welding torch; c is the diagram of the high - temperature ceramic wire guide sleeve; d is the top view of the special welding torch.

[0030] In the figure: 1. First wire feeder; 2. Gas cylinder; 3. First gas metal arc welding power source; 4. Second wire feeder; 5. Specialized welding torch: 5-1. No. 1 wire guide tube; 5-2. No. 2 wire guide tube; 5-3. No. 3 wire guide tube; 5-4. No. 4 wire guide tube; 5-5. Shielding gas inlet pipe; 5-6. Insulating wood; 5-7. Gas sieve; 5-8. Ceramic nozzle; 5-9. Conductive tip; 5-10. High-temperature ceramic wire guide sleeve; 6. Third wire feeder; 7. Second gas metal arc welding power source; 8. Fourth wire feeder; 9. Substrate.

[0031] Figure 3 It is a cross-coupled arc stability state diagram.

[0032] Figure 4 Schematic diagram of an alternating current arc rotating arc.

[0033] Figure 5 Schematic diagram of the current waveform for controlling the rotating arc. Specific implementation manners

[0034] In order to further understand the content, characteristics and effects of the present invention, the following embodiments are listed and described in detail in conjunction with the accompanying drawings as follows:

[0035] The basic idea of the present invention: A multi-wire rotating arc additive manufacturing device and control method based on cross-coupled arcs are proposed. Two gas metal arc welding power sources, four wire feeders and a specialized welding torch are used to form two cross-shaped welding circuits. When the magnetic fields generated by two perpendicular currents act on the arc, the arc shows a specific arc-wrapping behavior, generating a U-shaped arc formed by the overlap and coupling of two C-shaped arcs. Different from the traditional welding process where the wire and the substrate form a welding circuit, the heat input to the substrate and the deposited area during the welding process is reduced. By changing the positions of the four conductive tips in the welding torch and the wire feeding methods of the wire feeders, the stable existence interval and the adjustable range of the cross-coupled arc are increased. At the same time, by applying an alternating current with variable polarity to the two gas metal arc welding power sources, the U-shaped arc formed by the cross-coupled arc alternately switches the arc polarity along the arc-wrapping direction of the coupled arc, and macroscopically, the overall arc rotates in the same direction. The molten droplets formed by the melting of the welding wire also stably transition towards the rotation center along the direction of the rotating arc, solving the problem of different melting efficiencies due to the pole region effect, realizing the controllable efficiency of the four melting poles, and further realizing the stable transition of the arc polarity and the reasonable distribution of the heat generation in the arc pole region. At the same time, the four wire feeders can feed wires of different materials to manufacture the required high-strength alloy, solving the problem of the difficult preparation of special wires for high-strength alloy additive manufacturing.

[0036] Such as Figure 1The shown multi-wire rotary arc additive manufacturing device based on cross-coupled arcs is characterized in that it includes a special multi-wire additive welding torch (5), a substrate (9), a gas cylinder (2), a first gas metal arc welding power source (3), a second gas metal arc welding power source (7), a first wire feeding mechanism (1), a second wire feeder (4), a third wire feeder (6), and a fourth wire feeder (8), where: the first gas metal arc welding (3), the second gas metal arc welding power source (7), the first wire feeding mechanism (1), the second wire feeder (4), the third wire feeder (6), the fourth wire feeder (8), and the special multi-wire additive welding torch (5) are connected to form a multi-wire rotary arc additive manufacturing device based on cross-coupled arcs.

[0037] As Figure 2 The shown special multi-wire additive welding torch includes a first wire guiding tube (5-1), a second wire guiding tube (5-2), a third wire guiding tube (5-3), a fourth wire guiding tube (5-4), a shielding gas inlet pipe (5-5), an insulating wood (5-6), a gas sieve (5-7), a ceramic nozzle (5-8), a contact tip (5-9), and a high-temperature ceramic wire guiding sleeve (5-10). Among them, the special welding torch (5) uses an axial gas inlet method to reduce the volume of the welding torch. The insulating wood (5-6) is opened with holes at a specific angle and connected to the four wire guiding tubes and the contact tip, playing the role of insulation and high-temperature resistance. The gas sieve (5-7) is made by opening small holes on the insulating wood, and its purpose is to improve the protection effect on the welding torch and reduce the turbulence degree of the shielding gas entering the nozzle. The ceramic nozzle (5-8) is connected to the main body of the welding torch by bolts. The purpose of using the ceramic nozzle is to prevent short circuit with the workpiece and be resistant to high temperature, keep the gas flow uniform and stable during the additive process, have good gas flow rate and arc stiffness. The high-temperature ceramic wire guiding sleeve can increase and restrict the dry elongation of the welding wire and preheat the welding wire, and at the same time it can also prevent the contact tip from back burning.

[0038] The positive and negative poles of the first gas metal arc welding power source are respectively connected to the wire materials on the first and third wire feeders and the first and third wire guiding tubes of the special welding torch to form a first welding circuit; the positive and negative poles of the second gas metal arc welding power source are respectively connected to the wire materials on the second and fourth wire feeders and the second and fourth wire guiding tubes of the special welding torch to form a second welding circuit. These two welding circuits form a cross-shaped cross arc at the welding torch end. As Figure 3 As shown, when the magnetic fields generated by two perpendicular currents act on the arc, the arc shows a specific arc-wrapping behavior. The arc wraps around the electrode, generating a U-shaped arc formed by the overlap and coupling of two C-shaped arcs. The heat generated by the U-shaped arc is mainly used to melt the wire material, and the gravity and the arc force along the gravity direction are used for droplet transfer, realizing the decoupling of heat-mass-force during the additive process, reducing the heat input to the already formed deposition layer during the additive process, preventing the deposition layer from generating remelting defects, and at the same time improving the heat source utilization rate.

[0039] The first and second gas metal arc welding power sources adopt variable polarity AC power sources. As Figure 5 shown, the output waveforms of the two power sources are the same. The initial waveform of the first gas metal arc welding is 1 / 4 cycle faster than that of the second gas metal arc welding, ensuring that the U-shaped arc formed by the cross-coupled arc alternately switches the arc polarity along the arc winding direction of the coupled arc. Macroscopically, the overall arc rotates in the same direction as Figure 4 shown. The molten droplets formed by the melting of the welding wire also stably transition towards the rotation center along the direction of the rotating arc, solving the problem of different melting efficiencies due to the pole region effect, achieving controllable efficiency of the four melting poles, and further realizing the stable transition of the arc polarity and the reasonable distribution of heat generation in the arc pole region.

[0040] The wire in the first wire feeder (1) is introduced into the corresponding contact tip through the first wire guide tube (5-1) on the welding torch. The wire in the second wire feeder (4) is introduced into the corresponding contact tip through the second wire guide tube (5-2) on the welding torch. The wire in the third wire feeder (6) is introduced into the corresponding contact tip through the third wire guide tube (5-3) on the welding torch. The wire in the fourth wire feeder (8) is introduced into the corresponding contact tip through the fourth wire guide tube (5-4) on the welding torch. The first, second, third, and fourth wire feeders are independent of each other, and the two gas metal arc welding power sources corresponding to the wire feeders are also independent of each other and are adjusted independently. Among them, the first and second wire feeders adopt the constant wire feeding method to adjust their respective wire feeding speeds respectively. The third and fourth wire feeders adopt the arc voltage feedback variable speed wire feeding method to adjust their respective wire feeding speeds respectively, preventing the generated arc from being disordered or even extinguished. At the same time, this wire feeding speed control method can well avoid the problems of the cathode region effect of multi-wire additive manufacturing and different melting efficiencies of the four-terminal welding wires, enabling the stable progress of the rotating arc and molten droplet transfer.

[0041] Example 1:

[0042] Taking the deposition of a five-layer thin-walled aluminum alloy component as an example, as Figure 1 shown, connect the additive manufacturing device that controls the stable multi-wire rotating arc and molten droplet transfer. Fix the special welding torch to the three-dimensional motion mechanism, and make the three-dimensional motion mechanism drive the welding torch to move. The first and second gas metal arc welding power sources used are two Miller welding machines, and the four wire feeders are adjustable-speed ordinary wire feeders. The specific steps are as follows:

[0043] Step 1: Polish the surface of the 5A06 aluminum alloy substrate with sandpaper to remove the surface oxide film. Place the substrate on the surface of the workbench, and through the three-dimensional motion mechanism controller, adjust the relative position of the special welding torch and the additive substrate so that it is 6 mm above the substrate;

[0044] Step 2: Place four coils of ER4043 aluminum alloy wire into four wire feeders respectively. Turn on the power of the wire feeders and set the wire feeding speed to 2 m / min. The 1st and 2nd wire feeders adopt the equal-speed wire feeding adjustment method, and the 3rd and 4th wire feeders adopt the arc voltage feedback variable-speed wire feeding method to adjust the wire feeding speed. Set the shielding gas flow rate to 15 L / min. Turn on two Miller welders and use alternating current with variable polarity. The initial waveform of the 1st Miller welder is 1 / 4 cycle faster than that of the 2nd Miller welder, and the welding current is 120 A.

[0045] Step 3: Start the two Miller welders simultaneously first, and then start the four wire feeders. Perform additive deposition according to the planned path. Move the welding torch to the end point of the deposition layer, turn off the four wire feeders and the two Miller welders in sequence, and then pass the shielding gas for 5 s to prevent the deposition layer from oxidation.

[0046] Step 4: After the deposition layer cools for 40 - 90 s, raise the height of the welding torch by 4 mm

[0047] Step 5: Repeat Steps 1 - 4 in a cycle for deposition, and finally form the required component.

Claims

1. A multi-wire additive manufacturing device based on cross-coupled arcs, characterized in that: It includes a special multi-wire additive welding torch (5), a substrate (9), a gas cylinder (2), a first gas metal arc welding power source (3), a second gas metal arc welding power source (7), a first wire feeder (1), a second wire feeder (4), a third wire feeder (6) and a fourth wire feeder (8); The special multi-wire additive welding torch (5) includes a first wire guide tube (5-1), a second wire guide tube (5-2), a third wire guide tube (5-3), a fourth wire guide tube (5-4), a shielding gas inlet pipe (5-5), an insulating wood (5-6), a gas sieve (5-7), a ceramic nozzle (5-8), a contact tip (5-9) and a high-temperature ceramic wire guide sleeve (5-10); The first wire feeder (1), the second wire feeder (4), the third wire feeder (6) and the fourth wire feeder (8) are respectively installed in the first wire guide tube (5-1), the second wire guide tube (5-2), the third wire guide tube (5-3) and the fourth wire guide tube (5-4) of the special multi-wire additive welding torch (5), and the special multi-wire additive welding torch (5) faces the substrate (9); the gas cylinder (2) is installed in the shielding gas inlet pipe (5-5) of the special multi-wire additive welding torch (5), and the first gas metal arc welding power source (3) is respectively connected to the wire guide tubes of the second wire feeder (4) and the third wire feeder (6), and the second gas metal arc welding power source (7) is respectively connected to the wire guide tubes of the first wire feeder (1) and the fourth wire feeder (8); The insulating wood (5-6) is connected to the first wire guide tube (5-1), the second wire guide tube (5-2), the third wire guide tube (5-3), the fourth wire guide tube (5-4) and the contact tip (5-9) through openings; the gas sieve (5-7) is a small hole provided on the insulating wood to reduce the turbulence of the shielding gas entering the ceramic nozzle (5-8); the ceramic nozzle (5-8) is arranged at the end of the special multi-wire additive welding torch (5) and is connected to the special multi-wire additive welding torch (5); the contact tip (5-9) is arranged inside the ceramic nozzle (5-8), and a high-temperature ceramic wire guide sleeve (5-10) is arranged circumferentially around the contact tip (5-9). The high-temperature ceramic wire guide sleeve (5-10) can increase and restrict the dry elongation of the welding wire and preheat the welding wire, and at the same time prevent the contact tip (5-9) from back burning.

2. The multi-wire additive manufacturing device based on cross-coupled arcs according to claim 1, characterized in that: The special multi-wire additive welding torch (5) uses an axial gas inlet method.

3. The multi-wire additive manufacturing device based on cross-coupled arcs according to claim 1, wherein: The angles of the openings of the insulating wood (5-6) and the first wire guide tube (5-1), the second wire guide tube (5-2), the third wire guide tube (5-3), the fourth wire guide tube (5-4) can be adjusted synchronously. The four wire guide tubes change angles synchronously, and the angle changes from the wire guide tube being perpendicular to the horizontal plane to 60 degrees.

4. The multi-wire additive manufacturing device based on cross-coupled arcs according to claim 1, wherein: The positive and negative electrodes of the first gas metal arc welding power source (3) are respectively connected to the wire materials on the first wire feeder (1) and the third wire feeder (6), and the first wire guide tube (5-1) and the third wire guide tube (5-3) to form a first welding circuit; the positive and negative electrodes of the second gas metal arc welding power source (7) are respectively connected to the wire materials on the second wire feeder (4) and the fourth wire feeder (8), and the second wire guide tube (5-2) and the fourth wire guide tube (5-4) to form a second welding circuit; the two welding circuits form a cross-shaped arc at the end of the special multi-wire additive manufacturing welding torch (5); when the magnetic fields generated by two perpendicular currents act on the cross-shaped arc, the cross-shaped arc shows an arc-wrapping behavior, and the cross-shaped arc wraps around the electrode, generating a U-shaped arc formed by the overlap and coupling of two C-shaped arcs.

5. The multi-wire additive manufacturing device based on cross-coupled arcs according to claim 4, wherein: The heat generated by the U-shaped arc is mainly used to melt the wire material, and the gravity and the arc force along the gravity direction are used for droplet transfer, realizing the decoupling of heat-mass-force in the additive manufacturing process, reducing the heat input to the already formed deposition layer during the additive manufacturing process, preventing the deposition layer from generating remelting defects, and at the same time improving the heat source utilization rate.

6. The multi-wire additive manufacturing device based on cross-coupled arcs according to claim 1, characterized in that: The first gas metal arc welding power source (3) and the second gas metal arc welding power source (7) adopt variable polarity alternating current power sources; the output waveforms of the two alternating current power sources are the same, and the initial waveform of the first gas metal arc welding generated by the first gas metal arc welding power source (3) is 1 / 4 cycle faster than the second gas metal arc welding generated by the second gas metal arc welding power source (7), ensuring that the U-shaped arc formed by the cross-coupled arc alternately switches the arc polarity along the arc-wrapping direction of the coupled arc, and the macroscopic manifestation is that the arc rotates in the same direction as a whole; the droplets formed by the melting of the wire also stably transition to the rotation center along the direction of the rotating arc, solving the problem of different melting efficiencies due to the pole region effect, realizing the controllable efficiency of the four melting poles, and further realizing the stable transition of the arc polarity and the reasonable distribution of the heat generation in the arc pole region.

7. The multi-wire additive manufacturing device based on cross-coupled arcs according to claim 1, characterized in that: The wire material in the first wire feeder (1) is introduced into the corresponding contact tip (5-9) through the first wire guide tube (5-1) on the welding torch, the wire material in the second wire feeder (4) is introduced into the corresponding contact tip (5-9) through the second wire guide tube (5-2) on the welding torch, the wire material in the third wire feeder (6) is introduced into the corresponding contact tip (5-9) through the third wire guide tube (5-3) on the welding torch, and the wire material in the fourth wire feeder (8) is introduced into the corresponding contact tip (5-9) through the fourth wire guide tube (5-4) on the welding torch.

8. The multi-wire additive manufacturing device based on cross-coupled arcs according to claim 1, wherein: The first wire feeder, the second wire feeder, the third wire feeder, and the fourth wire feeder are independent of each other, and the two gas metal arc welding power sources corresponding to the wire feeders are also independent of each other and are adjusted independently; among them, the first wire feeder and the second wire feeder adopt the constant speed wire feeding method to adjust their respective wire feeding speeds, and the third wire feeder and the fourth wire feeder adopt the arc voltage feedback variable speed wire feeding method to adjust their respective wire feeding speeds; the wire materials used are all metals.

9. The multi-wire additive manufacturing device based on cross-coupled arcs according to claim 1, wherein: In the special welding torch, four wire guide tubes are arranged in a circumferential pattern at equal angles, and the extension wires of the contact tips are arranged in a cross shape; the intake pipe of the gas cylinder is connected to the intake port in the special welding torch, and the gas used in the gas cylinder is an inert gas.

10. The multi-wire additive manufacturing control method based on cross-coupled arc for the multi-wire additive manufacturing device according to any one of claims 1-9, characterized in that: It includes the following steps: Step 1: Pretreat the surface of the workpiece to be deposited before cladding, and fix the pretreated workpiece on the substrate; Step 2: Connect to the multi-wire rotary arc additive manufacturing device based on the cross-coupled arc, and select appropriate current waveforms and wire feeding speeds according to the deposited layer; Step 3: Start the first gas shielded metal arc welding power source and the second gas shielded metal arc welding power source simultaneously, then start four wire feeders, and perform additive deposition according to the planned path; move the welding torch to the end point of the deposited layer, turn off the four wire feeders, the first and second gas shielded metal arc welding power sources in sequence, and then pass the shielding gas to prevent the deposited layer from oxidation; Step 4: After the deposited layer cools, raise the height of the welding torch Step 5: Repeat Steps 1 to 4 in a cycle to deposit, and finally form the required component.

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