A device and method for in-situ forming composite heat treatment of large complex components

Abstract

The present application belongs to the field of additive manufacturing, and specifically discloses an apparatus and method for in-situ forming composite heat treatment of large and complex components. The apparatus includes a first robot, a second robot, and a third robot arranged around a workbench, and also includes an arc additive unit and a laser additive unit fixed to the first robot, an ultrasonic forging unit fixed to the second robot, and a heat treatment unit fixed to the third robot. The arc additive unit and the laser additive unit are used to perform zoned additive manufacturing on large and complex components; the ultrasonic forging unit is used to perform in-situ ultrasonic forging on the deposited layer; and the heat treatment unit is used to perform in-situ heat treatment on the deposited layer after ultrasonic forging. The present application can realize zoned additive manufacturing of large and complex components, improve additive efficiency and achieve high-precision forming, while reducing the anisotropy of the formed parts, improving mechanical properties, and quickly eliminating residual stress, reducing deformation and cracking.

Description

Technical Field

[0001] The present application belongs to the field of additive manufacturing, and more specifically, relates to an apparatus and method for in-situ forming composite heat treatment of large and complex components. Background Art

[0002] Large, complex components are key load-bearing components of high-end equipment, and their forming quality directly impacts their service life and safety. However, traditional forging processes for these components are subject to long production cycles, high production costs, and extremely high equipment tonnage requirements. They are also prone to macro- and micro-defects such as uneven structure and disrupted streamlines, necessitating the development of new forming processes.

[0003] As an advanced manufacturing technology that achieves integrated forming by accumulating materials layer by layer, metal additive manufacturing technology has the characteristics of high material utilization, short manufacturing cycle, low cost and mold-free forming. Therefore, it has incomparable advantages over other manufacturing methods in the manufacture of large and complex components. For example, arc additive manufacturing technology has a high deposition efficiency and is suitable for rapid additive manufacturing of large and complex components, while laser additive technology has a high forming accuracy and is suitable for high-precision forming of fine structures of large and complex components. However, since additive components are essentially cast structures, it is difficult to avoid additive defects such as shrinkage cavities and structural inhomogeneity, and anisotropy often exists inside the formed components. In addition, additive components generally require subsequent heat treatment to improve the structure and enhance performance. However, in the overall heat treatment of large components, problems such as structural inhomogeneity, large residual stress, and easy cracking often occur due to excessive differences in the temperature field. Summary of the Invention

[0004] In response to the defects of the existing technology or the need for improvement, the present application provides a device and method for in-situ forming composite heat treatment of large complex components, aiming to solve the problem of difficult coordinated control of the shape properties during the overall forming process of large components.

[0005] According to one aspect of the present application, a device for in-situ forming composite heat treatment of large complex components is provided, which specifically includes a first robot, a second robot and a third robot arranged around a workbench, and also includes an arc additive unit and a laser additive unit fixed to the first robot, an ultrasonic forging unit fixed to the second robot and a heat treatment unit fixed to the third robot, wherein the arc additive unit and the laser additive unit are used for performing partitioned additive manufacturing on large complex components; the ultrasonic forging unit is used for performing in-situ ultrasonic forging on a deposited layer; and the heat treatment unit is used for performing in-situ heat treatment on the deposited layer after ultrasonic forging.

[0006] Through the above technical solutions conceived in the present application, compared with the existing technology, the present application can perform zoned additive manufacturing according to structural characteristics by setting up arc additive units and laser additive units, thereby improving the additive efficiency and forming accuracy. At the same time, by setting up ultrasonic forging units and heat treatment units, the deposited layer can be ultrasonically forged and heat treated in situ, avoiding the problems of uneven structure, large residual stress and easy cracking in large and complex components.

[0007] As a further preferred embodiment, the arc additive unit includes a welding gun, a welding power supply, a welding wire and a wire feeder, wherein the welding gun is fixed at the front end of the arm of the first robot and is connected to the welding power supply; one end of the welding wire passes through the welding gun, and the other end thereof is connected to the wire feeder.

[0008] As a further preferred embodiment, the laser additive unit includes a laser head, a laser generator, a powder tank and a powder feeding pipe. The laser head is fixed at the front end of the arm of the first robot and connected to the laser generator; the powder tank is connected to the laser head through the powder feeding pipe for feeding metal powder into the laser head.

[0009] As a further preference, the relative distance between the laser head and the welding gun is 2 mm to 8 mm, the defocus amount of the laser head is 2 mm to 4 mm, and the angle between the laser head and the vertical direction is 0 to 10°.

[0010] As a further preference, the ultrasonic forging unit includes an ultrasonic generator and an ultrasonic forging head, the ultrasonic generator is connected to the ultrasonic forging head, and is used to provide ultrasonic waves; the ultrasonic forging head is fixed at the front end of the arm of the second robot, and is used to apply ultrasonic forging to the deposited layer after the molten pool solidifies.

[0011] As a further preferred embodiment, the heat treatment unit includes an air cooling component and an electromagnetic induction heating component, the air cooling component includes an air spray gun and a gas refrigerator, the air spray gun is fixed at the front end of the arm of the third robot and connected to the gas refrigerator, and is used to provide cooling gas to the deposited layer after ultrasonic forging; the electromagnetic induction heating component includes an electromagnetic induction heating coil and an electromagnetic induction heating power supply, the electromagnetic induction heating coil is fixed at the front end of the arm of the third robot and is connected to the electromagnetic induction heating power supply, and is used to perform electromagnetic induction heating on the deposited layer after ultrasonic forging.

[0012] According to another aspect of the present invention, there is provided a method for additive manufacturing using the above-mentioned device, the method comprising:

[0013] S1 performs partition planning and additive trajectory planning for large and complex components;

[0014] S2 uses an arc additive unit and a laser additive unit to perform partitioned additive manufacturing according to the planning results of step S1, and simultaneously uses an ultrasonic forging unit and a heat treatment unit to perform in-situ ultrasonic forging and in-situ heat treatment on the deposited layer in sequence, thereby producing a large and complex component.

[0015] As a further preference, in step S2, for regions with simple structures, laser-assisted arc additive manufacturing in a wire feeding mode is adopted, and for regions with fine structures, arc-assisted laser additive manufacturing in a powder feeding mode is adopted.

[0016] As a further preference, in the laser-assisted arc additive manufacturing, the arc welding current is 110A to 160A, and the laser power is 200W to 400W; in the arc-assisted laser additive manufacturing, the laser power is 1kW to 2kW, and the arc welding current is 60A to 80A.

[0017] As a further preference, the voltage of the electromagnetic induction heating power supply in the in-situ heat treatment unit is 220V to 550V, the temperature of the cooling gas is -20°C to -30°C, and the flow rate of the cooling gas is 30L / min to 50L / min.

[0018] In general, the above technical solutions conceived by this application have the following technical advantages compared with the existing technologies:

[0019] 1. This application, by providing an arc additive unit and a laser additive unit, can achieve zoned additive manufacturing of large and complex components. Arc additive manufacturing in a wire-feeding mode is performed in areas with simple structures, greatly improving additive efficiency. Laser additive manufacturing in a powder-feeding mode is performed in areas with fine structures, achieving high-precision forming. Furthermore, by providing an ultrasonic forging unit and a heat treatment unit, in-situ ultrasonic forging and in-situ heat treatment of the deposited layer can be achieved, reducing the anisotropy of the formed part, improving mechanical properties, and rapidly eliminating residual stress, thereby reducing deformation and cracking.

[0020] 2. In particular, the present application optimizes the structure of the heat treatment unit and utilizes the synergistic effect of the air cooling component and the electromagnetic induction heating component to achieve precise control of the temperature of the deposited layer, thereby effectively achieving in-situ heat treatment;

[0021] 3. In addition, the present application also provides a method for in-situ forming composite heat treatment of large and complex components, which realizes laser-arc composite heat source forming, can adjust the additive mode according to the structure of different formed components, and uses low-power laser to assist arc additive manufacturing in areas with simple structures. The low-power laser has an attraction and stabilizing effect on the arc, can compress the arc, increase the melting depth, and can also provide anode spots to prevent arc drift and suppress arc jumping, thereby improving the stability of the forming process; arc-assisted high-power laser additive manufacturing is used in areas with fine structures. Laser has the advantages of high energy density and high forming accuracy. For materials with high surface reflectivity to laser, such as aluminum alloy, the laser utilization rate is reduced. The introduction of arc-assisted laser additive manufacturing reduces the required laser energy, increases the laser energy density and the material's absorption rate of the laser, increases the stability of the forming process, and improves the forming efficiency and forming effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the device for in-situ forming composite heat treatment of large complex components provided in an embodiment of the present application;

[0023] Figure 2 Schematic diagram of the apparatus provided in an embodiment of the present application performing laser-assisted arc additive manufacturing in a wire feeding mode;

[0024] Figure 3 Schematic diagram of an apparatus provided in an embodiment of the present application performing arc-assisted laser additive manufacturing in a powder feeding mode;

[0025] Figure 4 Schematic diagram of an apparatus for performing in-situ ultrasonic forging according to an embodiment of the present application;

[0026] Figure 5 This is a schematic diagram of the in-situ heat treatment performed by the device provided in the embodiment of the present application.

[0027] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0028] 1- welding power supply, 2- wire feeder, 3- welding wire, 4- welding gun, 5- powder tank, 6- powder feeding tube, 7- laser head, 8- laser generator, 9- ultrasonic forging head, 10- second robot, 11- ultrasonic generator, 12- gas refrigerator, 13- hose, 14- workbench, 15- third robot, 16- electromagnetic induction heating power supply, 17- electromagnetic induction heating coil, 18- air spray gun, 19- deposition layer, 20- first robot, 21- laser beam, 22- molten pool, 23- metal powder, 24- arc, 25- plastic deformation layer, 26- cooling gas. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0030] like Figure 1 As shown, the present application provides an apparatus for in-situ forming composite heat treatment of large and complex aluminum alloy components, which specifically includes a first robot 20, a second robot 10 and a third robot 15 arranged around a workbench 14, and also includes an arc additive unit and a laser additive unit fixed on the first robot 20, an ultrasonic forging unit fixed on the second robot 10 and a heat treatment unit fixed on the third robot 15. The arc additive unit and the laser additive unit are used to perform zoned additive manufacturing on large and complex components. For areas with simple structures, laser-assisted arc additive manufacturing in a wire feeding mode is adopted. Arc additive manufacturing has the advantages of high forming efficiency and low manufacturing cost. The use of laser-assisted arc additive can be used for rapid forming of large and complex components. At the same time, laser assistance is introduced in the arc additive process, and the laser is used to The attraction and stabilizing effect of arc 24 improves the stability of arc 24 in arc additive manufacturing and improves the additive efficiency; for areas with fine structures, arc-assisted laser additive manufacturing in powder feeding mode is used. Because laser additive manufacturing has the advantages of high energy density and strong process controllability, laser additive manufacturing can meet both precise forming and high-performance forming. Arc 24 and laser preferably use CMT arc and fiber laser. The CMT welding power supply can switch between CMT, pulse, non-pulsed DC and other working modes. It adopts an integrated welding mode and will automatically match the corresponding welding voltage after selecting the welding current; the fiber laser uses optical fiber output, the optical path is simple, not prone to failure, the laser output power is stable, and it is more suitable for compounding with arc heat source. The maximum laser power is 3kW, and different laser power ranges are selected for different additive modes.

[0031] The ultrasonic forging unit is used to perform in-situ ultrasonic forging on the deposited layer 19. The plastic deformation generated by ultrasonic forging can form fine equiaxed crystals and eliminate additive defects, optimize the grain structure of the component, greatly reduce the anisotropy of the additive component, and improve the mechanical properties of the formed part.

[0032] The heat treatment unit is used to perform in-situ heat treatment on the deposited layer 19 after ultrasonic forging, quickly eliminate residual stress, reduce deformation and cracking, and avoid problems such as uneven structure, large residual stress, and easy cracking caused by excessive temperature field differences during overall heat treatment after forging of large additive components.

[0033] In order to solve the defects that are easy to occur during the manufacturing of large and complex components and the problems that are easy to occur during the overall heat treatment after forging, this application proposes to use the characteristics of high efficiency and low forming accuracy of arc additive manufacturing and high precision and low additive efficiency of laser additive manufacturing to carry out partitioned manufacturing of large and complex components. At the same time, in-situ ultrasonic forging and in-situ heat treatment technology are introduced in the process of partitioned additive manufacturing of large and complex components. Ultrasonic forging is used to eliminate additive defects, and then the area after ultrasonic forging is heat treated in situ to avoid the problems of uneven structure, large residual stress, and easy cracking that are easy to occur during the overall heat treatment of large additive components after forging. High-efficiency, low-cost and high-performance overall forming of large and complex components is carried out to realize online additive-forging-heat treatment.

[0034] Furthermore, the arc additive unit includes a welding gun 4, a welding power supply 1, a welding wire 3 and a wire feeder 2. The welding gun 4 is fixed at the front end of the arm of the first robot 20 and is connected to the welding power supply 1; one end of the welding wire 3 passes through the welding gun 4, and the other end thereof is connected to the wire feeder 2, which is used to feed the welding wire 3 into the welding gun 4.

[0035] Furthermore, the laser additive unit includes a laser head 7, a laser generator 8, a powder tank 5 and a powder feeding tube 6. The laser head 7 is connected to the front end of the arm of the first robot 20 through a connector, and the laser head 7 is also connected to the laser generator 8. The powder tank 5 is connected to the laser head 7 through the powder feeding tube 6, and is used to feed metal powder 23 into the laser head 7. The relative position between the laser head 7 and the welding gun 4, the defocus of the laser, and the angle between the laser head and the vertical direction can all be adjusted through the connector. The relative distance between the laser head 7 and the welding gun 4 is 2mm to 8mm, the defocus of the laser head 7 is 2mm to 4mm, and the angle between the laser head 7 and the vertical direction is 0 to 10°. Specifically:

[0036] The distance between the welding torch 4 and the laser head 7 is called the heat source spacing. This spacing primarily affects the interaction between the laser plasma and the arc plasma, as well as the droplet transfer pattern. When the heat source spacing is too large, the laser action point gradually shifts from the bottom of the molten pool to the edge of the molten pool, resulting in lower energy utilization. When the heat source spacing is smaller, the laser action point is located at the bottom of the molten pool, the liquid aluminum alloy temperature is higher, and the laser energy utilization rate is higher. Therefore, the heat source spacing is set to be between 2mm and 8mm, the distance between the laser beam 21 and the arc 24. Within this heat source spacing range, the droplet transfer pattern is stable, as is the arc current and arc voltage, resulting in a stable forming process and better forming quality.

[0037] During the laser additive manufacturing process, the position of the focal plane of the laser beam 21 can be changed by adjusting the defocus value, thereby determining the size of the light spot irradiated on the workpiece surface and affecting the forming of the deposited layer 19. In the process of changing the defocus from negative defocus to zero defocus, the parent material changes from incomplete penetration to full penetration. When the positive and negative defocus are large, the focal plane is far away from the material surface. According to the propagation characteristics of the Gaussian beam, the laser spot area on the material surface is large, the power density is low, and the laser energy absorption rate of the material is significantly reduced, so a defocus of 2mm to 4mm is used.

[0038] Since aluminum alloy materials have a high reflectivity to lasers, it will cause a lot of energy consumption and waste. Therefore, during the forming process, it is necessary to adjust the angle between the laser beam and the vertical direction to a certain angle to improve the utilization rate of the laser energy. However, when the deflection angle of the laser beam 21 is too large, the actual laser energy acting on the inside of the molten pool is low, which will lead to waste of heat source energy. Therefore, the adjustable angle range is 0 to 10°.

[0039] Furthermore, in the program compiled in wire feeding mode, the selectable arc current range is 110A to 160A, the laser power range is 200W to 400W, the powder feed rate is set to 0, the wire feed speed is 8m / min to 9m / min, and the travel speed is 2m / min to 2.2m / min. In the program compiled in powder feeding mode, the selectable laser power is 1kW to 2kW, the arc current range is 60A to 80A, the wire feed speed is set to 0, the powder feed rate is 10g / min to 12g / min, and the travel speed is 0.4m / min to 0.6m / min.

[0040] Furthermore, the ultrasonic forging unit includes an ultrasonic generator 11 and an ultrasonic forging head 9. The ultrasonic generator 11 is connected to the ultrasonic forging head 9 for providing ultrasonic waves. The ultrasonic forging head 9 is vertically fixed at the front end of the arm of the second robot 10 for applying ultrasonic forging to the deposited layer 19 after the molten pool solidifies.

[0041] Furthermore, the heat treatment unit includes an air cooling assembly and an electromagnetic induction heating assembly. The air cooling assembly includes an air lance 18 and a gas refrigerator 12. The air lance 18 is fixed to the front end of the arm of the third robot 15 and connected to the gas refrigerator 12 via a hose 13. It is used to provide cooling gas to the deposited layer 19 after ultrasonic forging. The electromagnetic induction heating assembly includes an electromagnetic induction heating coil 17 and an electromagnetic induction heating power supply 16. The electromagnetic induction heating coil 17 is fixed to the front end of the arm of the third robot 15 and connected to the electromagnetic induction heating power supply 16. It is used to electromagnetically heat the deposited layer after ultrasonic forging. The electromagnetic induction heating coil 17 is arranged in front of the air lance 18 and moves with the air lance 18 through the third robot 15. The electromagnetic induction coil 17 is made of a hollow copper tube with an outer diameter of 8mm and an inner diameter of 4mm, and the pitch is approximately 8mm. The electromagnetic induction coil 17 is shaped like a mosquito coil and is heated by alternating current supplied by an electromagnetic induction heating power supply 16. The frequency of the electromagnetic induction heating power supply 16 is fixed at 90kHz, and the voltage applied to the electromagnetic induction heating coil 17 is adjustable within a range of 220V to 550V. The air-cooling assembly uses compressed air, which is highly recyclable and economical. The air spray gun 18 sprays cooling gas at the ultrasonically forged area. The gas used is compressed air, which is highly recyclable, with a flow rate of 30L / min to 50L / min and a temperature of -20°C to -30°C.

[0042] During operation, the residual heat of the additive material is utilized and an electromagnetic induction heating component is used to quickly heat the ultrasonically forged parts. The cooling gas ejected by the air spray gun 18 is then used to reduce the temperature, thereby effectively achieving in-situ heat treatment. This can quickly eliminate residual stress, reduce deformation and cracking, and avoid problems such as uneven structure, large residual stress, and easy cracking that are prone to occur in the overall heat treatment of large additive components after forging.

[0043] Furthermore, the device also includes a control unit, which is connected to the first robot 20, the second robot 10, the third robot 15, the arc additive unit, the laser additive unit, the ultrasonic forging unit and the heat treatment unit for controlling them. The control unit is used to control the transition between the wire feeding mode and the powder feeding mode, and different additive modes are used for manufacturing in different structural areas.

[0044] According to another aspect of the present invention, a method for additive manufacturing using the above-mentioned device is provided, the method comprising:

[0045] S1 performs zoning planning and additive trajectory planning for large and complex components, using feature recognition algorithms to divide large and complex components into simple structural areas and fine structural areas;

[0046] S2 uses an arc additive unit and a laser additive unit to perform partitioned additive manufacturing according to the planning results of step S1, and simultaneously uses an ultrasonic forging unit and a heat treatment unit to perform in-situ ultrasonic forging and in-situ heat treatment on the deposited layer in sequence, thereby producing a large and complex component.

[0047] As a further preference, in step S2, for areas with simple structures, laser-assisted arc additive manufacturing in wire feeding mode is adopted, the heat input is mainly arc, and laser is used as an auxiliary heat source; for areas with fine structures, arc-assisted laser additive manufacturing in powder feeding mode is adopted, the heat input is mainly laser, and arc is used as an auxiliary heat source.

[0048] Furthermore, in laser-assisted arc additive manufacturing, the arc welding current is 110A to 160A, and the laser power is 200W to 400W; in arc-assisted laser additive manufacturing, the laser power is 1kW to 2kW, and the arc welding current is 60A to 80A. The ultrasonic forging unit operates at a frequency of 20 kHz, an amplitude of 20μm to 40μm, and a travel speed of 8cm / min to 16cm / min. When ultrasonic forging is performed in areas with simple structures, the operating frequency of the ultrasonic forging device is 20 kHz, the amplitude is 40μm, and the travel speed of the ultrasonic forging head is 16cm / min. When ultrasonic forging is performed in areas with finer structures, the operating frequency of the ultrasonic forging device is 20 kHz, the amplitude is 20μm, and the travel speed is 8cm / min. In areas with simple structures of large components, the cross-section is generally thicker. Smaller ultrasonic amplitudes produce a smaller plastic deformation layer 25, resulting in less significant ultrasonic forging effects. Therefore, a larger ultrasonic amplitude of 40μm is selected. Fine-structured areas are generally thinner in cross-section. To prevent deformation caused by larger ultrasonic amplitudes, a smaller ultrasonic amplitude of 20 μm is used. The direction of ultrasonic forging is controlled by the second robot 10, allowing for ultrasonic forging to be applied to the deposited layer at any position and angle, no longer limited to the direction normal to the surface of the deposited layer or at a slight angle to the surface normal.

[0049] Furthermore, the voltage of the electromagnetic induction heating power supply 16 in the in-situ heat treatment unit is 220V to 550V, the temperature of the cooling gas is -20°C to -30°C, and the flow rate of the cooling gas is 30L / min to 50L / min.

[0050] The specific steps of the in-situ forming composite heat treatment method for large complex components provided in this application are:

[0051] Step 1: Carry out zoning planning and additive trajectory planning for large and complex components. According to the size and shape of large and complex components, use MATLAB to extract the model slice data of large and complex components. Use feature recognition algorithm to divide large and complex components into simple and fine structural areas. Then build a three-dimensional model in STL format, perform slicing and layering, contour extraction and trajectory planning, import the final forming path into the process planning software, and import process parameters according to the additive mode of different partitions to form the corresponding robot additive trajectory code. The compiled robot trajectory code realizes automatic switching of laser and arc energy, and automatically changes the additive mode for different structural areas, thereby realizing high-efficiency, low-cost and high-performance overall forming of large and complex components.

[0052] Step 2: Build the device, specifically, install the substrate on the workbench 14, arrange the welding gun 4 and the laser head 7 at the front end of the arm of the first robot 20, connect the laser head 7 to the front end of the arm of the first robot 20 through a connector, connect the welding gun 4 and the laser head 7 to the welding power supply 1 and the laser generator 8 respectively, load the welding wire 3 into the wire feeder 2, adjust the dry extension length of the welding wire 3, connect the powder tank 5 to the laser head 7 through a pipeline, feed the metal powder 23 into the laser head, introduce arc additive shielding gas, laser additive shielding gas and powder feeding gas, arrange the ultrasonic forging head 9 at the front end of the arm of the second robot 10, arrange the air spray gun 18 and the electromagnetic induction heating coil 17 at the front end of the arm of the third robot 15, and use 20% CO2 + 80% Ar gas as the shielding gas. The arc additive shielding gas flow rate is set to 15L / min, the laser additive shielding gas flow rate is set to 7L / min, and the powder feeding gas uses pure argon gas, and the powder feeding gas flow rate is set to 4L / min.

[0053] Step 3: Setting of process parameters. Depending on the material, different welding modes of welding power sources and welding current, travel speed, wire feeding speed, laser power, and powder feeding rate of laser-arc composite additive can be selected. The relative position between the laser head 7 and the welding gun 4, the defocus amount of the laser, and the angle between the laser head 7 and the vertical direction are adjusted through the connector. The travel speed, impact frequency, amplitude of the ultrasonic forging head 9, the gas flow rate and gas temperature of the air spray gun, and the working power supply of the electromagnetic induction heating device are selected.

[0054] Step 4: Optimization of process parameters. Use ANSYS to simulate the arc and molten pool morphology during ultrasonic-assisted laser-arc composite heat source additive manufacturing. The composite heat source simulates the laser-arc composite heat source, which can better simulate the actual situation of the composite heat source during real additive manufacturing. First, establish a finite element model of laser-arc composite heat source additive manufacturing, and perform composite heat source additive manufacturing simulation. First, simulate the small laser power assisted arc additive manufacturing in the wire feeding mode to determine the optimal arc heat input and laser power as well as the optimal travel speed and wire feeding speed when additive manufacturing in a simple structure area. Then, perform the arc assisted large laser power in the powder feeding mode. The simulation of additive manufacturing with high rate is carried out to determine the optimal arc current and laser power as well as the optimal travel speed and powder feeding rate when performing additive manufacturing in areas with fine structures. Then, a finite element model of ultrasonic-assisted laser-arc composite heat source additive manufacturing is established to simulate the arc and molten pool morphology under different ultrasonic forging parameters, obtain the influence of different ultrasonic forging parameters on the arc and molten pool morphology, determine the optimal ultrasonic forging parameters, and then simulate the additive temperature field after ultrasonic forging, simulate the influence of the synergistic effect of electromagnetic induction heating and cooling gas on the temperature field of the deposited layer, and determine the optimal gas flow rate and gas temperature under in-situ heat treatment.

[0055] Step 5: Start the partitioned additive manufacturing of large and complex components, turn on the shielding gas and powder feeding gas, select the programmed trajectory command, use the robot teaching device to determine the starting point of welding, then turn on the welding power supply 1, select the appropriate welding current, travel speed, wire feeding speed, laser power, powder feeding rate and travel speed of the ultrasonic forging head in the control unit, and in the additive area with a simple structure, the first robot 20 arm with the welding gun 4 and the laser head 7 starts to add materials according to the predetermined trajectory, with the welding gun 4 feeding the wire and the laser head 7 stopping feeding the powder, and performing low-power laser-assisted arc additive manufacturing. The ultrasonic generator 11 is started at the same time, and ultrasonic forging is applied to the deposited layer after the molten pool 22 solidifies. The working frequency of the ultrasonic forging is 20KHz and the amplitude is 20μm~40μm. When the additive material is added to the area with fine structure, the compiled robot program realizes the automatic conversion of the additive mode. The first robot 20 arm carries the welding gun 4 and the laser head 7 to start additive material according to the predetermined trajectory. The laser head 7 feeds powder, the wire feeder 2 stops feeding wire, and arc-assisted high-power laser is used for additive material. At the same time, the ultrasonic forging head is used to apply ultrasonic forging to the deposited layer after the molten pool 22 solidifies.

[0056] Step 6: Perform in-situ heat treatment. After ultrasonic forging, the electromagnetic induction heating component and the air cooling component are activated. The third robot 15, carrying the electromagnetic induction heating coil 17 and the air spray gun 18, performs in-situ heat treatment on the ultrasonic forged area. The motion trajectory of the third robot 15 is similar to that of the first robot 20. First, the electromagnetic induction heating component is used to quickly heat the material to the effective temperature range for in-situ heat treatment using the residual heat after the material is added. Then, the air cooling component is activated and cooling gas is used to achieve the critical cooling rate for in-situ heat treatment. The synergistic effect of electromagnetic induction heating and gas cooling is used to increase and decrease the temperature, thereby performing effective in-situ heat treatment. The gas flow rate of the air cooling component is 30L / min to 50L / min, the gas temperature is -20℃ to -30℃, the power frequency of the electromagnetic induction heating device is fixed at 90kHz, and the voltage applied to the coil is adjustable in the range of 220V to 550V.

[0057] When running the program compiled according to the wire feeding mode, the system executes the laser-assisted arc additive manufacturing in the wire feeding mode to perform rapid forming of the component, while ultrasonic forging and in-situ heat treatment are performed at the rear at the same time. The wire is fed by the wire feeder 2, the powder tank 5 stops feeding powder, and the laser head 7 only serves to generate a laser heat source. The laser head is located in front of the welding gun 4. The laser located in the front has an attraction and stabilization effect on the arc located in the rear. At the same time, in the direction of travel of the welding gun, the laser contacts the substrate before the arc, which can play a role in preheating the substrate, making the spread of the molten pool 22 more uniform during the additive process, improving the forming quality of the subsequent deposited layer, and increasing the additive efficiency. The laser power in the wire feeding mode is 200W to 400W. The smaller laser power excites less aluminum alloy metal vapor and laser plasma, and the attraction and stabilization effect on the arc is not obvious. Excessive laser power will cause the heat input to increase accordingly, causing the molten pool 22 to overflow and collapse, making the appearance quality of the formed part worse. This laser power range can better ensure the composite effect between the laser and the arc. During implementation, if Figure 3 As shown, when running a program compiled for the powder feeding mode, the system executes arc-assisted laser additive manufacturing in powder feeding mode, achieving high-precision component forming, while ultrasonic forging and in-situ heat treatment are simultaneously performed. Powder is fed by powder tank 5, wire feeder 2 stops feeding wire, and the welding gun serves only as an arc heat source. Welding gun 4 is located in front of laser head 7. The welding gun contacts the substrate before the laser head in the direction of travel of the six-axis robot arm, which can preheat the substrate and generate a liquid molten pool, reducing the aluminum alloy's reflectivity to the laser and improving the utilization of laser energy.

[0058] Among them, the laser power in the powder feeding mode is 1kW~2kW. Laser additive manufacturing has the advantages of high laser energy density, strong process controllability, and high forming accuracy. Therefore, it can achieve high-precision forming for areas with fine structures.

[0059] Among them, when automatically switching to the additive mode, the laser-arc composite heat source needs to rotate 180° to change the relative position of the laser head and the welding gun. In order to ensure that the composite heat source avoids colliding with the additive test piece during the rotation process, it is necessary to control the first robot 20 to be raised to a certain height to smoothly complete the rotation of the composite heat source. Therefore, when automatically switching to the additive mode, the front end of the arm of the first robot 20 returns to a safe position.

[0060] During implementation, ultrasonic forging is applied to the deposited layer after solidification of the molten pool in the two additive modes. Ultrasonic forging and additive processing are carried out simultaneously. The effects of ultrasonic forging are divided into two categories: one is the influence of ultrasonic impact on the liquid aluminum alloy at the interface front during solidification, such as Figure 2 、 3 As shown in Figure 2, it mainly includes ultrasonic cavitation effect and acoustic streaming effect. The second is the effect of ultrasonic forging on the aluminum alloy structure after the molten pool solidifies, such as Figure 4 As shown, it mainly includes plastic deformation and recrystallization. In this way, the ultrasonic cavitation effect generated by ultrasonic forging can make the tiny bubble nuclei in the liquid aluminum alloy expand, compress, oscillate and finally collapse at high speed. The acoustic streaming effect can accelerate the internal flow of the liquid aluminum alloy to uniformize the temperature field, reduce the temperature gradient, and make the solute distribution in the molten pool uniform, thereby affecting the solidification process. The plastic deformation layer 25 generated by ultrasonic forging can strengthen the surface of the formed part, such as Figure 4 As shown, the additive defects are eliminated, the grain structure of the component is optimized, and the anisotropy of the arc additive component is greatly reduced.

[0061] During implementation, the ultrasonic forging parts are subjected to in-situ heat treatment, such as Figure 5As shown, in-situ heat treatment is achieved through an electromagnetic induction heating device and an air cooling device. The electromagnetic induction heating coil and the air spray gun are arranged at the front end of the third six-axis robot arm and move together with the third six-axis robot arm. First, the residual heat of the deposited layer after the addition is used to quickly heat the deposited layer to the in-situ heat treatment temperature range of 450°C to 550°C for aluminum alloys using the electromagnetic induction heating device. Then, the air spray gun sprays cooling gas 26 to quickly cool the temperature, achieving effective in-situ heat treatment. The cooling gas used by the gas cooling device is compressed air, which has good recyclability and economy. The gas flow rate and gas temperature within this parameter range can achieve good in-situ heat treatment results. If the gas flow rate is too low and the gas temperature is too high, the critical cooling rate for in-situ heat treatment cannot be reached (for example, for 6063 aluminum alloy profiles, the minimum cooling rate within the critical cooling temperature range is 38°C / min), and in-situ heat treatment cannot be performed. If the gas flow rate is too high and the gas temperature is too low, it will cause energy consumption and waste. Therefore, when performing laser-assisted arc additive manufacturing in wire feeding mode, since the structure of the additive part is generally relatively coarse, a higher gas flow rate and a lower gas temperature are selected. The gas flow rate is 40L / min~50L / min, and the gas temperature is -25℃~-30℃. When performing arc-assisted laser additive manufacturing in powder feeding mode, since the structure of the additive part is generally relatively fine, a lower gas flow rate and a higher gas temperature are selected. The gas flow rate is 30L / min~40L / min, and the gas temperature is -20℃~-25℃.

[0062] Compared with the prior art, this application:

[0063] 1. It realizes the partitioned additive manufacturing of large and complex components. In the area with simple structure, the laser-assisted arc additive manufacturing in wire feeding mode is used to greatly improve its additive efficiency. In the area with fine structure, the arc-assisted laser additive manufacturing in powder feeding mode is used for high-precision forming. It overcomes the problems of low surface accuracy of single arc heat source additive forming and low efficiency and high cost of single laser heat source additive forming in the direct forming of large and complex components. It integrates the advantages of high forming efficiency of wire feeding mode and high forming accuracy of powder feeding mode, and uses laser-arc composite heat source for rapid direct forming and partitioned additive manufacturing of large and complex components.

[0064] 2. The combination of different forms of laser-arc composite heat sources is realized. The additive mode can be adjusted according to the structure of different forming components. In areas with simple structures, low-power laser-assisted arc additive manufacturing is used. Low-power laser has an attraction and stabilizing effect on the arc, which can compress the arc and increase the melting depth; it can also provide anode spots to prevent arc drift and suppress arc jumping, thereby improving the stability of the forming process; arc-assisted high-power laser additive manufacturing is used in areas with fine structures. Laser has the advantages of high energy density and high forming accuracy, but the surface reflectivity of aluminum alloy materials to laser is high, resulting in reduced laser utilization. Therefore, arc-assisted laser additive manufacturing is introduced. On the one hand, the preheating effect of the arc reduces the required laser energy, increases the laser energy density and the absorption rate of the aluminum alloy material to the laser, increases the stability of the forming process, and improves the forming efficiency and forming effect.

[0065] 3. This invention introduces ultrasonic forging in the zoned additive manufacturing of large, complex components. The effects of ultrasonic forging on the additive process fall into two main categories: first, the effect on the liquid metal in the melt pool at the interface front during solidification, primarily including ultrasonic cavitation and acoustic streaming. Second, the effects of ultrasonic forging on the solid metal structure primarily include plastic deformation and recrystallization. The plastic deformation produced by ultrasonic forging can form fine equiaxed crystals, eliminate additive defects, optimize the component's grain structure, significantly reduce the anisotropy of arc-added components, and improve mechanical properties.

[0066] 4. This invention introduces in-situ heat treatment in the zoned additive manufacturing of large, complex components. By utilizing the synergistic effect of electromagnetic induction heating and gas cooling, the temperature of the deposited layer after forging is increased and decreased, effectively achieving in-situ heat treatment. This effectively utilizes the residual heat of the deposited layer after additive manufacturing, reducing energy consumption, rapidly eliminating residual stress, and minimizing deformation and cracking. This avoids the problems of uneven structure, high residual stress, and cracking that often occur with overall heat treatment of large additive components after forging.

[0067] 5. The ultrasonic forging head 9, air spray gun 18 and electromagnetic induction heating coil 17 of the present invention are arranged at the front end of the robot arm, which can extend the processing range and realize ultrasonic forging and in-situ heat treatment of some extreme positions, such as the surface of the component perpendicular to the workbench plane.

[0068] 6. The device provided by the present invention can realize online additive manufacturing, forging and heat treatment, greatly improving the manufacturing efficiency of directly formed parts. The laser-arc composite device, ultrasonic forging device and in-situ heat treatment device are all arranged at the front end of the six-axis robot arm. The scale of the parts that can be manufactured is large, close to the maximum elongation of the robot arm.

[0069] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or combination thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0070] It should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0071] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0072] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0073] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A device for in-situ forming composite heat treatment of large complex components, characterized in that: The device comprises a first robot (20), a second robot (10) and a third robot (15) arranged around a workbench (14), and also comprises an arc additive unit and a laser additive unit fixed on the first robot (20), an ultrasonic forging unit fixed on the second robot (10) and a heat treatment unit fixed on the third robot (15). The arc additive unit and the laser additive unit are used to perform partitioned additive manufacturing on large and complex components. For regions with simple structures, laser-assisted arc additive manufacturing in a wire feeding mode is used to attract and stabilize the arc using a low-power laser. For the fine structural areas, arc-assisted laser additive manufacturing in powder feeding mode is adopted to utilize the preheating effect of the arc to reduce the required laser energy; the ultrasonic forging unit is used to perform in-situ ultrasonic forging on the deposited layer to act on the liquid metal and solid metal in the molten pool at the front edge of the interface; the heat treatment unit is used to perform in-situ heat treatment on the deposited layer after ultrasonic forging, and the heat treatment unit includes an electromagnetic induction heating component and an air cooling component. When working, the residual heat of the additive is utilized, and the electromagnetic induction heating component is used to quickly heat the part after ultrasonic forging, and then the cooling gas ejected by the air cooling component is used to reduce the temperature.

2. The device according to claim 1, wherein The arc additive unit comprises a welding gun (4), a welding power source (1), a welding wire (3) and a wire feeder (2); the welding gun (4) is fixed to the front end of the arm of the first robot (20) and is connected to the welding power source (1); one end of the welding wire (3) passes through the welding gun (4), and the other end thereof is connected to the wire feeder (2).

3. The device according to claim 1, wherein The laser additive unit comprises a laser head (7), a laser generator (8), a powder tank (5) and a powder feeding pipe (6); the laser head (7) is fixed to the front end of the arm of the first robot (20) and is connected to the laser generator (8); the powder tank (5) is connected to the laser head (7) through the powder feeding pipe (6) and is used to feed metal powder (23) into the laser head (7).

4. The device according to claim 3, characterized in that The relative distance between the laser head (7) and the welding gun (4) is 2 mm to 8 mm, the defocusing amount of the laser head (7) is 2 mm to 4 mm, and the angle between the laser head (7) and the vertical direction is 0° to 10°.

5. The device according to claim 1, wherein The ultrasonic forging unit comprises an ultrasonic generator (11) and an ultrasonic forging head (9), wherein the ultrasonic generator (11) is connected to the ultrasonic forging head (9) and is used to provide ultrasonic waves; the ultrasonic forging head (9) is fixed to the front end of the arm of the second robot (10) and is used to apply ultrasonic forging to the deposited layer after the molten pool solidifies.

6. The device according to claim 1, wherein The heat treatment unit includes an air cooling component and an electromagnetic induction heating component. The air cooling component includes an air spray gun (18) and a gas refrigerator (12). The air spray gun (18) is fixed at the front end of the arm of the third robot (15) and is connected to the gas refrigerator (12) for providing cooling gas to the deposited layer after ultrasonic forging. The electromagnetic induction heating component includes an electromagnetic induction heating coil (17) and an electromagnetic induction heating power supply (16). The electromagnetic induction heating coil (17) is fixed at the front end of the arm of the third robot (15) and is connected to the electromagnetic induction heating power supply (16) for electromagnetic induction heating the deposited layer after ultrasonic forging.

7. A method for additive manufacturing using the device according to any one of claims 1 to 6, characterized in that: The method is: S1 performs partition planning and additive trajectory planning for large and complex components; S2 uses arc additive unit and laser additive unit to perform zoned additive manufacturing according to the planning results of step S1, and uses ultrasonic forging unit and heat treatment unit to perform in-situ ultrasonic forging and in-situ heat treatment on the deposited layer in sequence, thereby producing large and complex components. For areas with simple structures, laser-assisted arc additive manufacturing in wire feeding mode is adopted to utilize low-power laser to attract and stabilize the arc. For areas with fine structures, arc-assisted laser additive manufacturing in powder feeding mode is adopted to utilize the preheating effect of the arc to reduce the required laser energy; the ultrasonic forging unit acts on the liquid metal and solid metal in the molten pool at the front edge of the interface, and the heat treatment unit utilizes the residual heat of the additive when working, and uses the electromagnetic induction heating component to quickly heat the area after ultrasonic forging, and then uses the cooling gas ejected by the air cooling component to reduce the temperature.

8. Utilize the method according to claim 7, characterized in that, In the laser-assisted arc additive manufacturing, the arc welding current is 110A to 160A, and the laser power is 200W to 400W; in the arc-assisted laser additive manufacturing, the laser power is 1kW to 2kW, and the arc welding current is 60A to 80A.

9. Utilization of the method according to claim 7, characterized in that, The voltage of the electromagnetic induction heating power supply (16) in the in-situ heat treatment unit is 220V to 550V, the temperature of the cooling gas is -20°C to -30°C, and the flow rate of the cooling gas is 30L / min to 50L / min.

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