Magnetic field control system and method for curved surface shape follow-up additive molten pool

Abstract

The invention relates to a magnetic field control system and method for a curved surface follow-up additive molten pool, and belongs to the technical field of additive manufacturing. The magnetic field control system for the curved surface follow-up additive molten pool comprises an additive module, an angle calculation module and a control module; the material adding module is used for carrying out shape follow-up material adding on the to-be-welded curved surface; the angle calculation module is used for calculating the rotation angle of the material adding module according to the planned curved surface shape follow-up material adding track; and the control module is used for adjusting the material adding module based on the rotation angle to generate a constant magnetic field, obtaining the reverse Lorentz force of the molten pool in the curved surface shape follow-up material adding process based on the constant magnetic field, and hindering flowing of the molten pool based on the reverse Lorentz force, so that the curved surface forming precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a magnetic field control system and method for a curved surface conformal additive molten pool. Background Art

[0002] Arc and laser directional energy deposition additive manufacturing technology (Direct energy deposition, DED) is widely used in the rapid manufacturing or repair and remanufacturing of key components in the fields of aerospace, energy, military industry, automobiles, etc. due to its advantages of high efficiency, high precision, and strong adaptability. The main process flow of additive manufacturing technology includes: 3D modeling, layered slicing, trajectory planning, additive forming, heat treatment and post-processing finishing, etc. Among them, layered slicing currently generally adopts the horizontal layered slicing method, which forms a three-dimensional entity by horizontally stacking layer by layer. However, when forming parts with curved surface feature structures, the horizontal layering method inevitably has a step effect, resulting in low surface forming accuracy, large finishing allowance, and when used for repair and remanufacturing, the repair layer and the existing base side wall are poorly fused, as well as pore inclusion defects. In addition, the thickness of a single layer of arc additive can reach 2.0~4.0mm, and the step effect is more significant, which seriously limits the additive manufacturing and repair and remanufacturing performance of key components in key areas; some scholars have proposed a surface conformal layered slicing additive manufacturing method, that is, taking the outer surface of the part as the reference, layered slicing is performed inward layer by layer, the surface additive trajectory is planned, and then the surface conformal additive forming is performed from bottom to surface, which directly overcomes the step effect of horizontal stratification, can form a surface conformal additive layer, and can form a gradient material structure from the surface to the inside, and the precision performance is significantly improved.

[0003] However, conformal additive forming on complex curved surfaces still faces key difficulties. When the welding gun is performing additive forming on a flat surface, the molten pool is always in a horizontal state. When conformal additive forming is performed on a curved surface, the curvature and local inclination angles of different regions are different, resulting in different spatial welding positions such as flat welding, horizontal welding, upward welding, and downward welding in different trajectory directions. At different positions, gravity has different effects on the flow state of the molten pool fluid, resulting in significant differences in the final weld bead morphology, making it difficult to obtain a uniform and consistent conformal repair layer on the curved surface. For example, under horizontal welding conditions, the lateral drag of gravity on the molten pool can easily cause the weld to deviate sideways, the acceleration of gravity in upward welding can easily form a hump discontinuous weld, and the deceleration of gravity in downward welding can easily cause the molten pool to oscillate. Summary of the invention

[0004] In view of this, it is necessary to provide a magnetic field control system and method for a curved surface conformal additive melt pool to solve the technical problem of unstable flow of the melt pool during curved surface conformal additive manufacturing, resulting in low curved surface forming accuracy.

[0005] In order to solve the above problems, the present invention provides a curved surface conformal additive melt pool magnetic field control system, which includes an additive module, an angle calculation module, and a control module; The additive module is used to perform conformal additive processing on the surface to be welded; The angle calculation module is used to calculate the rotation angle of the additive module according to the planned surface conformal additive trajectory; The control module is used to adjust the additive module based on the rotation angle to generate a constant magnetic field, obtain the reverse Lorentz force of the molten pool in the surface conformal additive process based on the constant magnetic field, and hinder the flow of the molten pool based on the reverse Lorentz force.

[0006] In a possible implementation, the additive module includes a welding gun nozzle, a driving motor, a driving gear, a driven gear, a rotating base, a left magnetic conductor, a right magnetic conductor, and a welding wire; The welding gun nozzle is connected to the driving motor through a clamp, the driving motor is connected to the driving gear, the driving gear is meshed with the driven gear for transmission, the rotating base is fixedly connected to the welding gun nozzle, the driven gear, the rotating base, the left magnetizer and the right magnetizer are fixedly connected and coaxial with the welding gun nozzle, and the welding wire is fixedly connected to the welding gun nozzle.

[0007] In a possible implementation, the position control accuracy of the drive motor is .

[0008] In a possible implementation, a transmission ratio between the driving gear and the driven gear is 3:1.

[0009] In a possible implementation, the additive module further includes an electromagnet left coil and an electromagnet right coil; The left coil of the electromagnet is sleeved on the left magnetic conductor, and the right coil of the electromagnet is sleeved on the right magnetic conductor. The winding direction of the left coil of the electromagnet is opposite to that of the right coil of the electromagnet, and they are connected to the same DC power supply, wherein the left coil of the electromagnet is wound counterclockwise, and the right coil of the electromagnet is wound clockwise.

[0010] In one possible implementation, the angle calculation module is specifically used to determine the gravity projection direction of the surface conformal additive trajectory point according to the planned surface conformal additive trajectory, and based on the gravity projection direction, respectively calculate the rotation angles of the driven gear, the driving gear, and the driving motor when the axes of the left electromagnet coil and the right electromagnet coil are perpendicular to the gravity projection direction.

[0011] In one possible implementation, the control module is specifically used to adjust the drive motor in real time based on the rotation angle of the drive motor, so as to achieve that after the axes of the left coil of the electromagnet and the right coil of the electromagnet are perpendicular to the gravity projection direction, a constant magnetic field is generated, and a reverse Lorentz force of the molten pool in the surface conformal additive process is obtained based on the constant magnetic field, and the flow of the molten pool is hindered based on the reverse Lorentz force.

[0012] On the other hand, the present invention also provides a method for controlling a magnetic field in a curved surface conformal additive molten pool, which is implemented by the curved surface conformal additive molten pool magnetic field control system as described above, and comprises the following steps: Performing conformal additive manufacturing on the surface to be welded based on the additive module; Calculating the rotation angle of the additive module based on the angle calculation module according to the planned surface conformal additive trajectory; Based on the control module, the additive module is adjusted based on the rotation angle to generate a constant magnetic field, based on the constant magnetic field, a reverse Lorentz force of the molten pool in the surface conformal additive process is obtained, and based on the reverse Lorentz force, the flow of the molten pool is hindered.

[0013] In a possible implementation, obtaining the reverse Lorentz force of the molten pool in the surface conformal additive process based on the constant magnetic field, and hindering the flow of the molten pool based on the reverse Lorentz force, includes: A preset equilibrium condition is provided, and in the process of surface conformal additive manufacturing, based on the constant magnetic field, the magnetic flux lines of the constant magnetic field are cut through the molten pool to obtain a reverse Lorentz force of the molten pool; The gravity tangential component of the molten pool on the curved surface is obtained, and when the reverse Lorentz force and the gravity tangential component of the molten pool meet the equilibrium condition, the molten pool is stopped from flowing.

[0014] In a possible implementation, the calculation formula of the equilibrium condition is: , in, is the reverse Lorentz force, is the tangential component of gravity in the molten pool, is the induced charge in the molten pool, is the component of the velocity of the molten pool along the tangent direction of the surface under gravity, is a constant magnetic field strength, is the gravity acting on the molten pool, is the local angle of the melt pool on the surface.

[0015] The beneficial effects of the present invention are as follows: the curved surface conformal additive molten pool magnetic field control system includes an additive module, an angle calculation module, and a control module. The rotation angle of the additive module is calculated according to the planned curved surface conformal additive trajectory to ensure that the direction of the magnetic field is always perpendicular to the tangent vector direction of gravity on the curved surface, thereby achieving the maximum cutting magnetic flux line angle, increasing the reverse force, and ensuring the reverse obstruction effect. The additive module is adjusted based on the rotation angle to generate a constant magnetic field, and the reverse Lorentz force of the molten pool in the curved surface conformal additive process is obtained based on the constant magnetic field. The flow of the molten pool is obstructed based on the reverse Lorentz force, and the downward flow of the molten pool is suppressed by the reverse Lorentz force, thereby overcoming the adverse effect of gravity on the molten pool, ensuring a uniform and consistent forming morphology, and improving the curved surface forming accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic structural diagram of an embodiment of a magnetic field control system for a curved surface conformal additive melt pool provided by the present invention; Figure 2 A schematic structural diagram of an embodiment of an additive module of a curved surface conformal additive melt pool magnetic field control system provided by the present invention; Figure 3 A schematic diagram of the connection between the left and right coils of the electromagnet and the power supply of the magnetic field control system for the curved surface conformal additive melt pool provided by the present invention; Figure 4 A flow chart of an embodiment of a method for controlling a magnetic field in a curved surface conformal additive manufacturing molten pool provided by the present invention; Figure 5 A schematic diagram of the structure of an additive module for the method for controlling the magnetic field of a curved surface conformal additive melt pool provided by the present invention; Figure 6 A schematic diagram of angle calculation of the method for controlling the magnetic field of a curved surface conformal additive melt pool provided by the present invention; Figure 7 A schematic diagram of the balance between the gravity tangential component of the molten pool and the reverse Lorentz force in the curved surface conformal additive molten pool magnetic field control method provided by the present invention. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0018] The present invention discloses a magnetic field control system for a curved surface conformal additive molten pool. Figure 1 is a schematic diagram of a magnetic field control system for a curved surface conformal additive melt pool provided by an embodiment of the present invention, please refer to Figure 1 , the curved surface conformal additive molten pool magnetic field control system 100 includes an additive module 110, an angle calculation module 120, and a control module 130; Additive module 110, used for performing conformal additive processing on the surface to be welded; An angle calculation module 120, used to calculate the rotation angle of the additive module according to the planned surface conformal additive trajectory; The control module 130 is used to adjust the additive module based on the rotation angle to generate a constant magnetic field, obtain the reverse Lorentz force of the molten pool in the surface conformal additive process based on the constant magnetic field, and hinder the flow of the molten pool based on the reverse Lorentz force.

[0019] Among them, through the joint action of the additive module 110, the angle calculation module 120, and the control module 130, the downward flow of the molten pool is suppressed, and the uniform weld bead morphology of the curved surface conformal additive is achieved without changing the position and the curved surface conformal additive trajectory.

[0020] In some embodiments, see Figure 2 , the additive module 110 includes a welding gun nozzle 111, a driving motor 112, a driving gear 113, a driven gear 114, a rotating base 115, a left magnetizer 116, a right magnetizer 117, and a welding wire 118; The welding gun nozzle 111 is connected to the driving motor 112 through a clamp, the driving motor 112 is connected to the driving gear 113, the driving gear 113 is meshed with the driven gear 114 for transmission, the rotating base 115 is fixedly connected to the welding gun nozzle 111, the driven gear 114, the rotating base 115, the left magnetizer 116 and the right magnetizer 117 are fixedly connected and coaxial with the welding gun nozzle 111, and the welding wire 118 is fixedly connected to the welding gun nozzle 111; The driven gear, rotating base, left and right magnets are fixed together to form a component. The driven gear, rotating base and welding gun nozzle are coaxial and can rotate around the welding gun axis. The driving motor is fixed on the welding gun nozzle through a clamp. The nozzle diameter is 20mm. The driving motor can make the driving gear rotate clockwise or counterclockwise. The rotation angle and speed are precisely controllable. The driving motor is a servo motor with a position control accuracy of The driving gear is meshed with the driven gear. The rotation of the driving gear can make the driven gear rotate accordingly. The driving gear, the rotating base and the nozzle diameter are equipped with bearings to ensure smooth rotation. The transmission ratio of the driving gear and the driven gear is n=3:1. The number of teeth of the driving gear is 17, the number of teeth of the driven gear is 51, and the gear module is 1.25.

[0021] The additive module 110 further includes an electromagnet left coil 119 and an electromagnet right coil 1110 ; The left electromagnet coil 119 is mounted on the left magnetizer 116, and the right electromagnet coil 1110 is mounted on the right magnetizer 117. The left electromagnet coil 119 and the right electromagnet coil 1110 are wound in opposite directions and connected to the same DC power supply, wherein the left electromagnet coil 119 is wound in a counterclockwise direction, and the right electromagnet coil 1110 is wound in a clockwise direction. For the connection diagram of the left and right coils of the electromagnet and the power supply, please refer to Figure 3 ,like Figure 3 As shown, the left and right coils of the electromagnet are wound in opposite directions. After the left and right coils of the electromagnet are powered by the same DC power supply, the left and right coils of the electromagnet form a constant magnetic field in the molten pool area at the end of the welding wire. The DC power supply voltage is 24V, the coil diameter is 10mm, the number of coils is 30, the left coil is wound counterclockwise, and the right coil is wound clockwise. The ends of the left and right coils of the electromagnet are flush with the end of the welding gun nozzle, and the left and right coils are connected in parallel to the same DC power supply, with the upper end connected to the positive pole and the lower end connected to the negative pole. The winding directions are opposite, ensuring that the magnetic field formed by the joint action of the left and right coils can pass through the molten pool area at the end of the welding wire.

[0022] In some embodiments, the angle calculation module 120 is specifically used to determine the gravity projection direction of the surface conformal additive trajectory point according to the planned surface conformal additive trajectory, and based on the gravity projection direction, calculate the rotation angles of the driven gear, the driving gear, and the driving motor when the axes of the left electromagnet coil and the right electromagnet coil are perpendicular to the gravity projection direction.

[0023] According to the planned surface conformal additive trajectory, the projection direction of gravity on the surface at different positions of the surface is analyzed, and the rotation angles of the driven gear, driving gear, and driving motor are calculated when the axis planes of the left and right coils of the electromagnet are perpendicular to the projection direction of gravity.

[0024] In some embodiments, the control module 130 is specifically used to adjust the drive motor 112 in real time based on the rotation angle of the drive motor 112, so as to realize that the axis of the electromagnet left coil 119 and the electromagnet right coil 1110 is perpendicular to the gravity projection direction, generate a constant magnetic field, obtain the reverse Lorentz force of the molten pool in the surface conformal additive process based on the constant magnetic field, and hinder the flow of the molten pool based on the reverse Lorentz force; The reverse Lorentz force is used to suppress or weaken the downward flow speed of the molten pool, overcome the adverse effect of gravity on it, and ensure a uniform and consistent forming morphology.

[0025] A specific embodiment of the present invention discloses a method for controlling a magnetic field in a curved surface conformal additive manufacturing molten pool. Figure 4 This is a flow chart of the method for controlling the magnetic field of a curved surface conformal additive melt pool provided by an embodiment of the present invention. Figure 4 , the magnetic field control method of the curved surface conformal additive melt pool includes: S401, performing conformal additive manufacturing on the surface to be welded based on the additive module; S402, calculating the rotation angle of the additive module based on the planned surface conformal additive trajectory based on the angle calculation module; S403, based on the control module, adjusting the additive module based on the rotation angle to generate a constant magnetic field, obtaining the reverse Lorentz force of the molten pool in the surface conformal additive process based on the constant magnetic field, and hindering the flow of the molten pool based on the reverse Lorentz force.

[0026] Among them, the driving motor, driving gear and driven gear in the additive module drive the angles of the left and right coils of the electromagnet to change in real time, ensuring that the direction of the magnetic field is always perpendicular to the gravity projection direction of the molten pool, thereby achieving the maximum cutting angle of the magnetic flux lines, increasing the reverse force, and ensuring the reverse obstruction effect.

[0027] Compared with the prior art, the curved surface conformal additive molten pool magnetic field control method provided in the present embodiment performs conformal additive on the curved surface to be welded based on the additive module; calculates the rotation angle of the additive module based on the planned curved surface conformal additive trajectory based on the angle calculation module to ensure that the direction of the magnetic field is always perpendicular to the tangent vector direction of gravity on the curved surface, thereby achieving the maximum cutting magnetic flux line angle, increasing the reverse force, and ensuring the reverse obstruction effect; the control module adjusts the additive module based on the rotation angle to generate a constant magnetic field, obtains the reverse Lorentz force of the molten pool in the curved surface conformal additive process based on the constant magnetic field, obstructs the flow of the molten pool based on the reverse Lorentz force, suppresses the downward flow of the molten pool through the reverse Lorentz force, overcomes the adverse effect of gravity on the molten pool, ensures a uniform and consistent forming morphology, and improves the curved surface forming accuracy.

[0028] In some embodiments, in step S401, the curved surface to be welded is subjected to conformal additive, the driving motor and the driving gear are assembled correctly, and the driving motor is installed on the welding gun nozzle through a fixture, and the assembly consisting of the driven gear, the rotating base, and the left and right magnetizers is correctly installed on the welding gun nozzle to ensure that the driving gear and the driven gear are correctly meshed, and the driven gear and the rotating base can rotate around the welding gun nozzle, and the left and right coils of the electromagnet are respectively installed on the left and right magnetizers to ensure that the left and right coils are wound in opposite directions and connected in parallel to the same DC power supply. When the motor is started, the driving gear rotates, driving the driven gear, the rotating base, the left magnetizer, the right magnetizer, the left coil of the electromagnet, and the right coil of the electromagnet to rotate. After the left and right coils of the electromagnet form a constant magnetic field in the molten pool area at the end of the welding wire, the planned curved surface conformal additive trajectory is subjected to conformal additive; For a schematic diagram of the additive module, see Figure 5 ,like Figure 5 As shown, the additive module includes a welding gun nozzle, a driving motor, a driving gear, a driven gear, a rotating base, a left magnetic conductor, a right magnetic conductor, a welding wire, a left electromagnet coil, and a right electromagnet coil.

[0029] In some embodiments, in step S402, the rotation angle of the additive module is calculated according to the planned surface conformal additive trajectory. According to the planned surface conformal additive trajectory, the projection direction of gravity on the surface at different positions of the surface is analyzed, and the rotation angles of the driven gear, the driving gear, and the motor are calculated when the planes of the axes of the left and right coils of the electromagnet are perpendicular to the gravity projection direction. For a schematic diagram of the angle calculation, please refer to Figure 6 ,like Figure 6 As shown, the world coordinate system is specified as , The direction is opposite to the direction of gravity. The initial posture of the tool coordinate system at the end of the welding gun coincides with the world coordinate system, that is, the axis of the welding gun is parallel Axis; when the welding gun moves to a certain position on the surface, the tool coordinate system at the end of the welding gun rotates to Attitude, now The vector direction is: ,in, For vector The component in the axial direction, For vector The component in the axial direction, ‌ is a vector in The component in the axial direction, A point on the ray Towards The projection of the plane is ,Pass do The vertical line , then the straight line and The angle is: , in, is the rotation angle of the driven gear, and the driving gear rotation angle is , is the transmission ratio of the driving gear to the driven gear. The rotation angle of the motor is the same as the rotation angle of the driving gear. The rotation angle is also .

[0030] In some embodiments, in step S403, the additive module is adjusted based on the rotation angle to generate a constant magnetic field, and the reverse Lorentz force of the molten pool in the process of curved surface conformal additive is obtained based on the constant magnetic field. The flow of the molten pool is hindered based on the reverse Lorentz force, and a balance condition is preset. In the process of curved surface conformal additive, the magnetic flux lines of the constant magnetic field are cut by the molten pool to obtain the reverse Lorentz force of the molten pool; the gravity tangential component of the molten pool on the curved surface is obtained, and when the reverse Lorentz force and the gravity tangential component of the molten pool meet the balance condition, the molten pool is stopped from flowing, and the gravity tangential component of the molten pool and the reverse Lorentz force are balanced. Please refer to the schematic diagram of Figure 7 ,like Figure 7As shown, the gravitational tangential component of the molten pool With the reverse Lorentz force The magnitude is equal and the direction is opposite; that is, the reverse Lorentz force is equal to the tangential component of the gravity of the molten pool, and the calculation formula for its equilibrium condition is: , in, is the reverse Lorentz force, is the tangential component of gravity in the molten pool, is the induced charge in the molten pool, is the component of the velocity of the molten pool along the tangent direction of the surface under gravity, is a constant magnetic field strength, is the gravity acting on the molten pool, is the local angle of the molten pool on the surface; In the process of surface conformal additive manufacturing, the rotation angle of the drive motor is calculated according to different position points of the surface conformal additive trajectory, and the drive motor is controlled to rotate to the corresponding rotation angle according to the rotation angle of the drive motor to ensure that at different positions of the curved surface, the planes of the axis of the left and right coils of the electromagnet are always perpendicular to the projection direction of gravity on the curved surface. The phase angle of the magnetic field is controlled by the drive motor to ensure that on the curved surface, when the molten pool is dragged by gravity to flow, it can correctly cut the magnetic flux lines, and the flowing molten pool cuts the magnetic flux lines to form a reverse Lorentz force to hinder the flow of the molten pool.

[0031] When adding material to a curved surface, the molten metal flows downward due to the drag of gravity, cutting the magnetic flux lines to generate a Lorentz force opposite to the flow velocity, which hinders the downward flow of the molten metal and thus suppresses the unstable flow of the molten pool, ensuring a uniform weld bead morphology. The left and right coils of the electromagnet rotate around the axis of the welding gun to change the direction of the magnetic field to adapt to the requirements of different gravity directions at different curved surface positions.

[0032] In summary, the present invention provides a curved surface conformal additive molten pool magnetic field control system and method, the curved surface conformal additive molten pool magnetic field control system includes an additive module, an angle calculation module, and a control module; the additive module is used to perform conformal additive on the curved surface to be welded; the angle calculation module is used to calculate the rotation angle of the additive module according to the planned curved surface conformal additive trajectory; the control module is used to adjust the additive module based on the rotation angle to generate a constant magnetic field, and obtain the reverse Lorentz force of the molten pool in the curved surface conformal additive process based on the constant magnetic field, and hinder the flow of the molten pool based on the reverse Lorentz force, thereby improving the curved surface forming accuracy.

[0033] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A magnetic field control system for a curved surface conformal additive melt pool, characterized in that: It includes additive module, angle calculation module and control module; The additive module is used to perform conformal additive processing on the surface to be welded; The angle calculation module is used to calculate the rotation angle of the additive module according to the planned surface conformal additive trajectory; The control module is used to adjust the additive module based on the rotation angle to generate a constant magnetic field, obtain the reverse Lorentz force of the molten pool in the surface conformal additive process based on the constant magnetic field, and hinder the flow of the molten pool based on the reverse Lorentz force.

2. The curved surface conformal additive melt pool magnetic field control system according to claim 1, characterized in that: The additive module includes a welding gun nozzle, a driving motor, a driving gear, a driven gear, a rotating base, a left magnetic conductor, a right magnetic conductor, and a welding wire; The welding gun nozzle is connected to the driving motor through a clamp, the driving motor is connected to the driving gear, the driving gear is meshed with the driven gear for transmission, the rotating base is fixedly connected to the welding gun nozzle, the driven gear, the rotating base, the left magnetizer and the right magnetizer are fixedly connected and coaxial with the welding gun nozzle, and the welding wire is fixedly connected to the welding gun nozzle.

3. The curved surface conformal additive melt pool magnetic field control system according to claim 2, characterized in that: The position control accuracy of the drive motor is .

4. The curved surface conformal additive melt pool magnetic field control system according to claim 2, characterized in that: The transmission ratio between the driving gear and the driven gear is 3:

1.

5. The curved surface conformal additive melt pool magnetic field control system according to claim 2, characterized in that: The additive module also includes an electromagnet left coil and an electromagnet right coil; The left coil of the electromagnet is sleeved on the left magnetic conductor, and the right coil of the electromagnet is sleeved on the right magnetic conductor. The winding direction of the left coil of the electromagnet is opposite to that of the right coil of the electromagnet, and they are connected to the same DC power supply, wherein the left coil of the electromagnet is wound counterclockwise, and the right coil of the electromagnet is wound clockwise.

6. The curved surface conformal additive melt pool magnetic field control system according to claim 5, characterized in that: The angle calculation module is specifically used to determine the gravity projection direction of the surface conformal additive trajectory point according to the planned surface conformal additive trajectory, and based on the gravity projection direction, respectively calculate the rotation angles of the driven gear, the driving gear, and the driving motor when the axes of the left electromagnet coil and the right electromagnet coil are perpendicular to the gravity projection direction.

7. The curved surface conformal additive melt pool magnetic field control system according to claim 6, characterized in that: The control module is specifically used to adjust the drive motor in real time based on the rotation angle of the drive motor to achieve a constant magnetic field after the axis of the left coil of the electromagnet and the right coil of the electromagnet are perpendicular to the gravity projection direction, obtain the reverse Lorentz force of the molten pool in the process of surface conformal additive manufacturing based on the constant magnetic field, and hinder the flow of the molten pool based on the reverse Lorentz force.

8. A method for controlling magnetic field of a curved surface conformal additive melt pool, characterized in that: The method is implemented by a curved surface conformal additive melt pool magnetic field control system as claimed in any one of claims 1 to 7, comprising the following steps: Performing conformal additive manufacturing on the surface to be welded based on the additive module; Calculating the rotation angle of the additive module based on the angle calculation module according to the planned surface conformal additive trajectory; Based on the control module, the additive module is adjusted based on the rotation angle to generate a constant magnetic field, based on the constant magnetic field, a reverse Lorentz force of the molten pool in the surface conformal additive process is obtained, and based on the reverse Lorentz force, the flow of the molten pool is hindered.

9. The method for controlling the magnetic field of a curved surface conformal additive melt pool according to claim 8, characterized in that: The method of obtaining a reverse Lorentz force of a molten pool in a curved surface conformal additive process based on the constant magnetic field, and hindering the flow of the molten pool based on the reverse Lorentz force, comprises: A preset equilibrium condition is provided, and in the process of surface conformal additive manufacturing, based on the constant magnetic field, the magnetic flux lines of the constant magnetic field are cut through the molten pool to obtain a reverse Lorentz force of the molten pool; The gravity tangential component of the molten pool on the curved surface is obtained, and when the reverse Lorentz force and the gravity tangential component of the molten pool meet the equilibrium condition, the molten pool is stopped from flowing.

10. The method for controlling the magnetic field of a curved surface conformal additive melt pool according to claim 9, characterized in that: The calculation formula of the equilibrium condition is: ， in, is the reverse Lorentz force, is the tangential component of gravity in the molten pool, is the induced charge in the molten pool, is the component of the velocity of the molten pool along the tangent direction of the surface under gravity, is a constant magnetic field strength, is the gravity acting on the molten pool, is the local angle of the melt pool on the surface.

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