Multi-wire multi-arc additive manufacturing method and equipment for large multi-metal propellers

Abstract

The present application belongs to the field of additive manufacturing, and particularly relates to a large multi-metal propeller multi-wire multi-arc additive manufacturing method and equipment. The present application uses Cu-Ni-Al alloy, 1500MPa ultra-high strength steel and 304L stainless steel to additively manufacture a propeller. The present application uses a three-dimensional hollow structure, and a periodically arranged hollow unit is designed in the propeller blade and hub. In the case of ensuring mechanical performance, the weight is greatly reduced. The present application designs a path planning method for additively manufacturing a large multi-metal multi-dimensional heterogeneous propeller, ensures the forming precision of the propeller, reduces the arc extinction rate in the manufacturing process, and thus improves the manufacturing efficiency. The present application uses three-wire CMT welding guns and two positioners to work in coordination, avoids prolonging the manufacturing cycle due to wire changing and position change in the additive process, and the use of three-wire CMT reduces the heat input in the additive process, thereby reducing defects such as cracks, residual stress and coarse grains of the propeller, and helping to improve the performance of the propeller.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing, specifically relating to a method and equipment for the multi-wire, multi-arc additive manufacturing of a large multi-metal propeller. Background Technology

[0002] Propellers are widely used in my country's shipbuilding, weaponry, and aviation industries, primarily converting mechanical energy into propulsion. They are the core components of the power systems of ships, helicopters, and other similar devices. Therefore, the manufacturing efficiency, precision, and overall performance of propellers have a significant impact on the mass production and high-precision manufacturing of the equipment involved. Currently, the most widely used propeller manufacturing process involves first creating the lower mold using a scraper and pitch plate, then creating the upper mold using a wooden or sand mold, casting the propeller blank using the mold, followed by rough machining of the propeller blades using a milling machine, and finally manual grinding and polishing using a grinding wheel or abrasive belt to ensure the precision and surface quality of the final product.

[0003] However, this processing method is relatively primitive. The creation of molds is difficult and time-consuming. Furthermore, the dimensional accuracy and performance of cast parts are poor, and the process is largely manual, resulting in low automation and production efficiency. To address these issues, arc-wire additive manufacturing (WAAM) has been introduced into the manufacture of large propellers in recent years. WAAM uses an electric arc as a heat source to melt the welding wire. A robot controls the welding torch to move along a pre-set path, and the liquid metal transitions to a substrate or the previous solidified metal layer under the influence of electromagnetic forces. This process transforms from point to line, and from line to surface, ultimately forming a three-dimensional part. This process reduces the need for mold making and significantly shortens the manufacturing cycle. Moreover, because WAAM is based on robots and open manufacturing platforms, it is also suitable for manufacturing large, complex-shaped parts.

[0004] However, further practice has shown that many problems still exist in the process of manufacturing propellers using arc additive manufacturing technology. First, most current additive propellers are solid structures, resulting in large mass and requiring significant load-bearing capacity from the positioner. This leads to high material costs and long manufacturing cycles. Furthermore, defects such as porosity and cracks are prone to occur, affecting their performance. While there are examples of additive hollow blades, the hollow structure results in weaker impact resistance, making them unsuitable for critical applications. Second, in the manufacturing of large additive propellers, the hub and blades are manufactured separately, requiring manual intervention. This increases labor costs and extends the manufacturing cycle. Therefore, further research and improvements are urgently needed in this field to better meet the demands for higher quality and efficiency in propeller component manufacturing. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a method and equipment for the multi-wire multi-arc additive manufacturing of large multi-metal propellers, which can realize the efficient and high-performance forming and manufacturing of large propellers by electric arc wire additive manufacturing.

[0006] Three different materials were used in the additive manufacturing of this propeller: Cu-Ni-Al alloy welding wire, 1500MPa ultra-high-strength steel welding wire, and 304L stainless steel. The Cu-Ni-Al alloy was deposited 5mm deep on the blade surface to further improve the propeller's corrosion resistance; 304L stainless steel was used for mesh forming and deposition between the unit cells to increase the propeller's strength; and 1500MPa ultra-high-strength steel was used for filling and forming within the mesh to improve the overall strength and other mechanical properties of the propeller. Furthermore, while maintaining stable structural mechanical properties, the weight of the propeller was minimized by employing a multi-dimensional hollow unit cell "splicing" structure for weight reduction. Finally, using these three materials, a three-wire welding torch was employed as the main equipment in the additive manufacturing motion system.

[0007] To achieve the above objectives, a large multi-metal propeller multi-wire multi-arc additive manufacturing equipment is provided, including a mechanical motion system, a control system, a wire feeding system, and a gas delivery system.

[0008] The mechanical motion system includes a robot equipped with a three-wire welding torch, an H-type positioner, and an HB-type positioner. The robot and the two positioners are all controlled by the control system, enabling them to work collaboratively to achieve specific working postures and improve manufacturing efficiency. The wire feeding system includes three sets of wire feeding wheels, three sets of wire feeding motors, and three sets of wire feeding interfaces. The control system controls the feeding of Cu-Ni-Al alloy welding wire, 1500MPa ultra-high-strength steel welding wire, and 304L stainless steel welding wire respectively. The gas delivery system consists of three sets of protective gas cylinders, three sets of gas pipelines, and three sets of flow meters. It delivers 100%Ar, 100%Ar, and 97.5%Ar+2.5%CO2 protective gases to the corresponding welding torch nozzles, and performs operations such as early gas delivery and delayed gas delivery under the control system.

[0009] Including additive power systems;

[0010] The additive power supply consists of three CMT power supplies that can communicate with each other. Under the control of the control system, they provide energy for the generation of the electric arc, thereby melting the welding wire to achieve additive manufacturing.

[0011] The electrode clamp at the nozzle of the three-wire welding torch is connected to the positive terminal of the welding power source, and the worktable is connected to the negative terminal of the power source.

[0012] A method for additive manufacturing of large multi-metal propellers using the above-described apparatus includes the following steps:

[0013] Step (1): Create a three-dimensional model of a large propeller and obtain the three-dimensional model STL file.

[0014] Step (2): Import the STL model into the layer slicing software, determine the welding process parameters for each pass, slice the hub of the heterogeneous propeller 3D model with a tangent parallel to the horizontal plane, and slice the blade of the model with a variable diameter cylinder tangent coaxial with the hub to obtain the slice data file of each layer.

[0015] Step (3): Perform path planning on each layer of the 3D model file after the slice processing in step S1. Based on the principle of first adding the inner and outer contours, then adding the mesh contours, and finally filling the mesh interior, obtain the program instructions that the actuator can recognize.

[0016] Step (4): Start the additive manufacturing device, supply protective gas, and use the rotor hub additive manufacturing program code obtained in step S3 to enable the robot equipped with the three-wire welding gun to move the welding gun along the planned path trajectory of the rotor hub on the H-type positioner, thereby realizing the forming and manufacturing of the Nth layer of the propeller hub. Initially, N=1.

[0017] Step (5): Make N = N + 1, and repeat step S4 until the additive manufacturing of the large multi-metal propeller hub is completed.

[0018] Step (6): The control system issues a command to rotate the H-type positioner 90 degrees along the axis and clamp the additively manufactured propeller hub onto the HB-type positioner. Using the program code obtained in step S3, the three-wire robot and the HB-type positioner work together to enable the robot equipped with the three-wire welding gun to form the Nth layer of the propeller blade on the rotating propeller hub wall according to the planned path, with N=1 initially.

[0019] Step (7): Make N = N + 1, and repeat step S6 until the additive manufacturing of the large multi-metal propeller blades is completed.

[0020] Specifically, in step (3), path planning includes contour processing, mesh processing, and internal filling processing. In contour processing, the welding torch performs contour offset scanning along the inner and outer contours of the hub and the outer contour of the blades; in mesh processing, a straight path is used to form the boundary of the unit cell; in internal filling processing, the welding torch fills the mesh using a partitioned scanning trajectory. This path planning method reduces post-weld residual stress, improves forming accuracy, reduces arc extinguishing rate, and improves manufacturing efficiency.

[0021] Furthermore, the outline is made of Cu-Ni-Al alloy to improve the propeller's corrosion resistance; the mesh is made of 304L stainless steel to improve the propeller's strength while reducing manufacturing costs; and the internal filling is made of 1500MPa ultra-high strength steel to improve the propeller's overall strength and other mechanical properties.

[0022] Furthermore, the molding process parameters for contour processing, mesh processing, and internal filling processing vary depending on the materials used.

[0023] Furthermore, constant forming process parameters are used to clad Cu-Ni-Al welding wire in the contour offset scanning forming process. The specific parameters are as follows: wire feed speed is 7.1~8.6m / min, welding speed is 6.0~10.0m / min, shielding gas type is 100%Ar, and shielding gas flow rate is 9~11L / min.

[0024] Furthermore, in the linear path scanning forming process, constant forming process parameters are used to clad 304L stainless steel. The specific parameters are as follows: wire feed speed is 3-5 m / min, welding speed is 10-12 m / min, the type of shielding gas is 97.5% Ar + 2.5% CO2, and the shielding gas flow rate is 18-22 L / min.

[0025] Furthermore, in the partitioned scanning filling process, constant forming process parameters are used to clad 1500MPa ultra-high strength steel. The specific parameters are as follows: wire feeding speed is 4-8m / min, welding speed is 3-10m / min, shielding gas type is 100%Ar, and shielding gas flow rate is 20-25L / min.

[0026] Specifically, in step (4), according to the determined robotic arm motion trajectory, while the welding torch moves in the (X, Y, Z) three-coordinate system, the tool posture angle coordinates (A, B, C) of the welding torch are adjusted in real time to realize the adjustment of the welding torch angle.

[0027] Specifically, in step (6), according to the determined path trajectory of the robotic arm, while the welding torch moves in the (X, Y, Z) three-coordinate system, the tool posture angle coordinates (A, B, C) of the welding torch are adjusted in real time to realize the adjustment of the welding torch angle; combined with the (A, B) axis linkage of the positioner, the multi-axis linkage of the welding torch is realized.

[0028] Specifically, in steps (4) to (7), the extension length of the welding wire at the welding torch nozzle is always kept at 15mm during the additive manufacturing process.

[0029] In general, the method and apparatus conceived by this invention have the following main technical advantages compared with the prior art:

[0030] 1. This invention uses three materials—Cu-Ni-Al alloy, 1500MPa ultra-high-strength steel, and 304L stainless steel—to create an additive propeller. Specifically, 304L stainless steel is used for mesh forming and deposition between unit cells, increasing propeller strength while reducing manufacturing costs; 1500MPa ultra-high-strength steel is used for filling and forming within the mesh, improving the overall strength and other mechanical properties of the propeller; and Cu-Ni-Al alloy is deposited 5mm onto the blade surface to further enhance the propeller's corrosion resistance.

[0031] 2. This invention adopts a three-dimensional hollow structure, with periodically arranged hollow units designed inside the blades and hub, which greatly reduces weight while ensuring mechanical performance; moreover, this three-dimensional hollow structure has a high degree of spatial symmetry, which can evenly decompose external loads, thus achieving weight reduction while ensuring load-bearing capacity.

[0032] 3. This invention designs a path planning method for additive large-scale multi-metal multi-dimensional heterogeneous propellers, ensuring propeller forming accuracy and reducing the arc extinction rate during manufacturing, thereby improving manufacturing efficiency. Specifically: in the contour processing, a contour offset scanning method is used for the inner and outer contours of the hub and the outer contour of the blades; in the mesh processing, a straight-line scanning path is used to form the unit boundary; in the internal filling processing, the welding torch uses a partitioned scanning method to fill the mesh. For irregular parts near the contour, adaptive hollowing elements are used, as shown in the attached figure.

[0033] 4. This invention uses a three-wire CMT welding gun and two positioners to work in coordination, avoiding the extension of the manufacturing cycle due to wire changes and station changes during the additive manufacturing process; moreover, the use of three-wire CMT reduces the heat input during the additive manufacturing process, thereby reducing defects such as cracks, residual stress and coarse grains in the propeller, which helps to improve the performance of the propeller.

[0034] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0035] Figure 1 This is a diagram of the large-scale multi-metal propeller multi-wire multi-arc additive manufacturing equipment constructed according to the present invention.

[0036] Figure 2 This refers to the working state of the actuator and the additive propeller hub of positioner 1.

[0037] Figure 3 This refers to the working status of the actuator and the additive blade of the positioner 2.

[0038] Figure 4 This is a schematic diagram of a unit of a large multi-metal propeller with a hollow structure.

[0039] Figure 5 This is a radial cross-sectional view of the hollowed-out structure of the propeller hub.

[0040] Figure 6 This is an axial cross-sectional view of the hollowed-out structure of the propeller hub.

[0041] Figure 7 This is a schematic diagram of one of the three groups of blades.

[0042] Figure 8 This is a cross-sectional path planning diagram of the blade obtained by cutting the blade with a cylindrical surface coaxial with the propeller hub.

[0043] Figure 9 It is the partition scan path that fills the inside of the grid.

[0044] Figure 10 This is a schematic diagram of the process for a multi-wire, multi-arc additive manufacturing method for large multi-metal propellers. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0046] like Figure 1 As shown, a large multi-metal propeller multi-wire multi-arc additive manufacturing equipment comprises a mechanical motion system, a three-wire feeding system, three gas delivery systems, a triangular three-wire welding torch, three CMT welding power supplies, and a control system.

[0047] The aforementioned mechanical motion system consists of an industrial robot collaborating with an H-type positioner and an HB-type positioner. These three devices can communicate with each other and work collaboratively under the control of a control system. The robot's end effector is connected to a triangular three-wire welding torch, which, under the control of the control system, carries the welding torch and moves stably within the arc space according to a pre-set program.

[0048] In the above-mentioned triangular three-wire welding torch, the three welding torch nozzles are distributed in an equilateral triangle.

[0049] The aforementioned three-wire feeding system is assembled from three sets of wire feeding rollers, a wire feeding motor, a wire feeding interface, and a housing, capable of feeding welding wires separately. The three sets of wire feeding rollers are respectively equipped with Cu-Ni-Al welding wire, 1500MPa ultra-high-strength steel welding wire, and 304L stainless steel welding wire. Under the control system, the welding wire is driven by the wire feeding motor to be fed to the corresponding welding torch nozzle at the time specified by the program instructions, and then melted by the electric arc to form molten droplets that are deposited onto the designated path.

[0050] The core components of the aforementioned gas delivery system are three sets of protective gas cylinders and connected gas delivery pipelines. The protective gas cylinder connected to the Cu-Ni-Al welding wire nozzle stores 100% Ar, the protective gas cylinder connected to the 1500MPa ultra-high strength steel welding wire nozzle stores 100% Ar, and the protective gas cylinder connected to the 304L stainless steel welding wire nozzle stores 97.5% Ar + 2.5% CO2. Under the control system, the gas delivery system can achieve pre-delayed gas delivery, thereby protecting the additive manufacturing area from the influence of external air.

[0051] The three sets of CMT welding power supplies mentioned above are the core devices that provide energy for this equipment. The positive terminal of the power supply is connected to the conductive clamp inside the welding torch, and the negative terminal is connected to the worktable (i.e., the two positioners).

[0052] like Figure 2 and Figure 3 As shown, a multi-wire, multi-arc additive manufacturing process for a large multi-metal propeller is implemented by an industrial robot equipped with a three-wire welding torch, an H-type positioner, and an HB-type positioner.

[0053] like Figure 2 As shown, according to the program code, the control system issues corresponding instructions, and the three-wire CMT robot controls the welding torch to move along the planned path on the worktable of the H-type positioner. It uses Cu-Ni-Al welding wire to complete the additive manufacturing of the outline part, uses 304L stainless steel welding wire to complete the additive manufacturing of the unit grid, and uses 1500MPa ultra-high strength steel welding wire to complete the grid filling, thereby completing the additive manufacturing of the hollow structure propeller hub.

[0054] like Figure 3 As shown, after the blade hub is completed, the control system issues a command to rotate the H-type positioner 90 degrees around the axis and clamp the completed blade hub onto the HB-type positioner. Under the action of the control system, the HB-type positioner clamps the blade hub and rotates around the axis continuously. The three-wire CMT robot generates an arc to melt the corresponding welding wire, which is then transferred to the blade hub wall. The two work together to complete the blade addition.

[0055] Combination Figure 5-8 The additive manufacturing methods for propeller hubs and blades are explained in detail.

[0056] like Figure 5 The image shown is a radial cross-sectional view of the propeller hub; as shown... Figure 6 The image shows an axial cross-sectional view of the propeller hub. It can be seen that the hub is composed of several stacked hollow unit bodies. For some irregularly shaped unit bodies, a hollow structure adapted to their outer contour is used, such as... Figure 6The outermost and innermost contours of the propeller hub are shown. Under the control of the control system, the three-wire robot controls the welding torch to clad the inner and outer contours of the Cu-Ni-Al alloy additive along the path obtained by contour offset. Then, it clads the internal mesh portion of the 304L stainless steel additive along a straight path. Finally, it clads the mesh interior with 1500MPa ultra-high strength steel using a partitioned scanning method (see partitioned scanning path). Figure 9 The process involves adding N=1 layers of material to the cross-section. Then, the welding torch is raised to a fixed height, and N=N+1 layers of material are added, stacked one by one, until the propeller hub is finally obtained.

[0057] like Figure 7 The diagram shown is a schematic of a propeller blade; as shown... Figure 8 As shown, this figure is a cross-sectional view of the blade cut by a variable-diameter cylinder coaxial with the blade hub. It can be seen that the blade is composed of regular cubic hollow units and adaptive outer contour hollow units. After the blade hub is clamped onto the HB-type positioner, the HB-type positioner, under the control of the control system, holds the blade hub and rotates it continuously around the axis. The three-wire robot controls the welding torch to clad the outer contour of the Cu-Ni-Al alloy additive blade along the path obtained by contour offset. Then, it clads the internal mesh portion of the 304L stainless steel additive along a straight path. Finally, it clads the mesh interior with 1500MPa ultra-high-strength steel using a partitioned scanning method (see partitioned scanning path). Figure 9 The process involves adding N=1 layers of material to the cross-section. Then, the welding torch is raised to a fixed height, and N=N+1 layers of material are added, stacked one by one, until the propeller hub is finally obtained.

[0058] Specifically, such as Figure 4 As shown, this regular hollow cube is the basic unit of the additive propeller structure. Through the periodic stacking of this unit, the hub and blades are additively constructed. The unit is made of 1500MPa ultra-high strength steel, and the units are clad with 304L stainless steel to meet its corrosion resistance requirements.

[0059] Figure 10 Flowchart of a multi-wire, multi-arc additive manufacturing method for large multi-metal propellers.

[0060] Example

[0061] A large multi-metal propeller additive manufacturing method and equipment was adopted, utilizing Cu-Ni-Al alloy, 1500MPa ultra-high strength steel and 304L stainless steel to produce a large additive propeller.

[0062] Step 1: Determine the additive manufacturing process for the three types of welding wires, conduct welding process experiments, measure parameters such as weld width and reinforcement height for each pass, and select the most suitable process parameters for additive manufacturing.

[0063] Step 2: Input parameters such as weld width and excess height into the layer slicing software. Use the layer slicing software to slice the propeller hub and blades in the established STL model, and then use the slice data for path planning.

[0064] For the propeller hub section, a plane that remains perpendicular to the propeller hub axis is first used as the cutting surface. Several layers of the propeller hub's cross-sectional data are obtained using a planar layering method. Within these multiple slices, the inner and outer contours of the hub on each cutting plane are calculated. Then, the inner and outer contours are offset outwards and inwards by 5mm respectively in a circular pattern to obtain the contour offset path for the Cu-Ni-Al alloy cladding. Next, a grid linear path is planned within the closed body to obtain the cladding path for 304 stainless steel. Finally, each grid is filled using a partitioned scanning method to obtain the cladding path for 1500MPa ultra-high strength steel.

[0065] For the propeller blade section, the blade section is divided into several layers of cross-sections using a variable-diameter cylindrical cross-section coaxial with the propeller hub. Then, the profile of the propeller blade on the cross-section is calculated, and the edge of the profile is offset inward by 5mm to obtain the profile offset path of Cu-Ni-Al alloy cladding. Next, grid straight-line path planning is performed in the closed body to obtain the cladding path of 304 stainless steel. Then, the interior of each grid is filled in a partitioned scanning manner to obtain the cladding path of 1500MPa ultra-high strength steel.

[0066] Then, the additive manufacturing program was written using the additive manufacturing path obtained from the slicing software.

[0067] Step 3: Start the additive manufacturing equipment, supply shielding gas, and the three-wire robot controls the welding torch to weld specific materials onto the H-type positioner according to the planned path and measured process parameters, completing the additive manufacturing of the propeller hub (e.g., Figure 2 As shown, during the additive manufacturing of the propeller hub, while the welding torch moves within the (X, Y, Z) three-coordinate system, the tool attitude angular coordinates (A, B, C) of the welding torch are adjusted in real time to achieve the adjustment of the welding torch angle. First, the external and internal contours of the propeller hub are additively manufactured using Cu-Ni-Al alloy; then, a mesh is additively manufactured to build a hollow structure contour using 304L stainless steel; finally, the mesh is filled using ultra-high strength steel. After the propeller hub additive manufacturing is completed, the H-type positioner is rotated 90° around its axis to clamp the propeller hub onto the HB-type positioner.

[0068] Step 4: The three-wire robot works in conjunction with the HB-type positioner. The robot, equipped with a three-wire welding torch, uses measured process parameters to clad specific materials onto the rotating rotor hub wall according to a planned path, achieving additive manufacturing of the propeller blades (e.g.,...). Figure 3(As shown). While the welding torch moves within the (X, Y, Z) three-coordinate system, the tool attitude angular coordinates (A, B, C) of the welding torch are adjusted in real time to achieve torch angle adjustment; combined with the (A, B) axis linkage of the positioner, multi-axis linkage of the welding torch is achieved. First, the outer contour of the blade is additively fabricated using Cu-Ni-Al alloy; then, the mesh is additively fabricated to build a hollow structure using 304 stainless steel; finally, the mesh is filled using ultra-high strength steel.

Claims

1. A large multi-metal propeller multi-wire multi-arc additive manufacturing method, characterized in that, The method comprises the following steps: S1, three-dimensional model establishment of propeller For the hollow structure propeller component, a three-dimensional model of the large propeller hollow structure is established in a spatial coordinate system by using three-dimensional modeling software; then, the three-dimensional model is processed in sections, wherein the propeller hub is taken as a first part and each propeller blade located on the side surface is taken as a plurality of second parts; S2, section path planning For the propeller hub part, firstly, a plane always perpendicular to the axis of the propeller hub is taken as a cutting plane, and a plurality of layers of the cutting surface data of the propeller hub are obtained by adopting the plane layering method; in the plurality of layers, the inner and outer contours of each cutting plane hub are calculated, and then the inner and outer contours are respectively offset outward and inward by 5mm, and then the grid path planning is performed in the closed body, and then each grid is filled in a section scanning manner; thus, the path planning of the entire propeller hub is completed as the cutting plane is gradually raised along with the cutting height; for the propeller blade part, firstly, the position of the propeller hub is adjusted by using a positioner so that the axis of the propeller hub is parallel to the horizontal plane, and then the blade part is divided into a plurality of layers of slices by adopting the method of slicing the blade part in layers by using a variable-diameter cylindrical surface coaxial with the propeller hub, and then the contour of the propeller blade on the cutting surface is calculated, and then the contour is gradually offset inward by 5mm from the edge of the contour, and then the grid path planning and the grid internal filling path planning are performed; thus, the path planning of all the propeller blades is completed one by one as the cylindrical surface is gradually raised along with the slicing height; S3, final forming based on CMT electric arc additive manufacturing According to the manufacturing path of the propeller hub and blade completed in step S2, the CMT electric arc additive manufacturing process is adopted to first complete the additive manufacturing of the hub on the positioner with the working surface horizontal to the ground, then the positioner is rotated by 90 degrees, the hub is clamped on the positioner with the working surface vertical to the ground, and the additive manufacturing of the blade is completed by the robot and the positioner in cooperation, thereby obtaining the required propeller component product.

2. The large multi-metal propeller multi-wire multi-arc additive manufacturing method of claim 1, wherein, Three different metals or alloys are used for additive manufacturing, which are Cu-Ni-Al alloy, 1500MPa ultra-high strength steel and 304 stainless steel.

3. The large multi-metal propeller multi-wire multi-arc additive manufacturing method of claim 1, wherein, The section path planning includes contour part processing, grid part processing and grid internal filling processing; in the contour part processing, the welding gun performs contour offset scanning forming along the inner and outer contours of the hub and the outer contour of the blade; in the grid part processing, a straight line path is adopted to realize the forming manufacturing of the unit body boundary; in the grid internal filling processing, the welding gun performs grid internal filling in a section scanning trajectory.

4. The large multi-metal propeller multi-wire multi-arc additive manufacturing method of claim 1, wherein in the process of additive forming of the hub, the tool posture angle coordinates (A, B, C) of the welding gun are controlled in real time while the welding gun moves in the (X, Y, Z) three-coordinate system, so as to realize adjustment of the welding gun angle; In the process of additive forming of the blade, the tool posture angle coordinates (A, B, C) of the welding gun are controlled in real time while the welding gun moves in the (X, Y, Z) three-coordinate system, so as to realize adjustment of the welding gun angle; combined with the (A, B) axis linkage of the positioner, multi-axis linkage of the welding gun is realized.

5. The large multi-metal propeller multi-wire multi-arc additive manufacturing method according to claim 1 or 2, characterized in that, Different metals or alloys are deposited in different areas; in the process of additive hub, the inner and outer contours are deposited with Cu-Ni-Al alloy, the internal grid is deposited with 304 stainless steel, and the internal grid is filled with 1500 MPa ultra-high strength steel; in the process of additive blade, the outer contour is deposited with Cu-Ni-Al alloy, the grid is still 304 stainless steel, and the internal grid is filled with 1500 MPa ultra-high strength steel.

6. The large multi-metal propeller multi-wire multi-arc additive manufacturing method of claim 1, 2 or 3, wherein, The hollow structure is adopted for the hub and the blade, the cube is taken as the hollow unit in the hub or the blade, the inner and outer contour lines are taken as the hollow unit near the inner and outer contours, and 304L stainless steel is used for cladding at the connection between the unit and the unit.

7. The large multi-metallic propeller multi-wire multi-arc additive manufacturing method of claim 1 wherein, In step S3, the key process parameters of the CMT arc additive manufacturing process include welding speed, wire feeding speed, type of shielding gas and shielding gas flow rate, and correspond to the selected wire material.

8. The large multi-metal propeller multi-wire multi-arc additive manufacturing method according to claim 7, characterized by, The Cu-Ni-Al wire feeding speed is 7.1-8.6 m / min, the Cu-Ni-Al wire welding speed is 6.0-10.0 m / min, the type of shielding gas is 100% Ar, and the shielding gas flow rate is 9-11 L / min; the 1500 MPa ultra-high strength steel wire feeding speed is 4-8 m / min, the 1500 MPa ultra-high strength steel wire welding speed is 3-10 m / min, the type of shielding gas is 100% Ar, and the shielding gas flow rate is 20-25 L / min; the 304L stainless steel wire feeding speed is 3-5 m / min, the 304L stainless steel wire welding speed is 10-12 m / min, the type of shielding gas is 97.5% Ar+2.5% CO2, and the shielding gas flow rate is 18-22 L / min.

9. An apparatus for large scale multi-metal propeller multi-wire multi-arc additive manufacturing method according to any one of claims 1-8, characterized in that, It comprises a mechanical motion system, a control system, a wire feeding system and a gas delivery system. The mechanical motion system comprises a robot equipped with a three-wire welding gun cooperating with an H-type positioner and an HB-type positioner, and the robot and the two positioners are controlled by the control system to work cooperatively to complete a specific working posture; the wire feeding system comprises three sets of wire feeding wheels, three sets of wire feeding motors and three sets of wire feeding interfaces, and the control system controls the feeding of alloy welding wire, ultra-high strength steel welding wire and stainless steel welding wire respectively; the gas delivery system comprises three sets of gas cylinders, three sets of gas pipelines and three sets of flowmeters, which deliver the shielding gas to the corresponding welding gun nozzles and complete the advance gas feeding and lag gas feeding under the action of the control system; It also comprises an additive power supply system; The additive power supply comprises three CMT power supplies that can communicate with each other, which provide energy for the generation of electric arc under the action of the control system, and then melt the welding wire to realize additive manufacturing; The electrode clip at the nozzle of the three-wire welding gun is connected to the positive electrode of the welding power supply, and the workbench is connected to the negative electrode of the power supply.

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