Ultrasonic impact-ultrasonic field assisted plasma arc additive manufacturing apparatus and processing method

Abstract

The application discloses an ultrasonic impact-ultrasonic field auxiliary plasma arc additive manufacturing device and a processing method, and the device comprises a plasma arc additive manufacturing device, an ultrasonic auxiliary device, a first mechanical arm, an ultrasonic impact device, a positioning clamp and a second mechanical arm; the plasma arc additive manufacturing device is fixed with the ultrasonic auxiliary device, is installed on the first mechanical arm through the plasma arc additive manufacturing device, and the second mechanical arm is connected with the ultrasonic impact device through the positioning clamp; the processing method of the device is as follows: 1) early installation; 2) debugging; 3) coaxial ultrasonic auxiliary additive; 4) ultrasonic impact; and 5) subsequent processing. Through synchronous movement of the coaxial ultrasonic auxiliary welding gun and the ultrasonic impact head, the intermediate ultrasonic auxiliary additive is realized, repeated high-frequency impacts are carried out on the molten cladding layer which is just formed and is in a softened state on both sides, the additive efficiency is improved, the size precision of the formed part is improved, the residual stress of the formed part is reduced, and the grains are refined, so that the purpose of controlling the shape and the property of the plasma arc additive manufacturing is realized.

Description

Technical Field

[0001] This invention relates to additive manufacturing apparatus and methods, specifically to an ultrasonic shock-ultrasonic field assisted plasma arc additive manufacturing apparatus and processing method. Background Technology

[0002] Plasma arc additive manufacturing uses a combined or transferred plasma arc as a heat source and alloy powder or wire as filler metal to effectively melt and bond the weld metal and the base metal, forming a high-density, high-bonding, and low-dilution weld structure, thus achieving additive manufacturing. It features high cladding efficiency, good metallurgical bonding of formed parts, low equipment operating costs, and great potential in manufacturing large and complex components.

[0003] Currently, plasma arc additive manufacturing technology still has significant shortcomings in terms of shape and property control in metal forming. Plasma arc additive manufacturing is a layer-by-layer stacking process. Due to the heat accumulation during processing, a temperature gradient is generated in the initially formed sections, leading to residual stress and warping deformation of the formed parts. Furthermore, the constantly changing heat accumulation in the initially formed sections increases the solidification time of the molten pool, enhancing fluidity and making it prone to "collapse" at the weld edges. This can easily lead to grain coarsening in the formed parts, resulting in uneven microstructure, and the solidified structure near the fusion line tends to grow into coarse columnar crystals. In addition, the rapid solidification rate of the molten pool during plasma arc additive manufacturing prevents timely gas escape, leading to increased porosity and reduced overall mechanical properties of the formed parts. Therefore, timely processing during the forming process can significantly improve the mechanical properties of the product and enhance manufacturing precision.

[0004] To address the aforementioned issues, patent CN106735967A discloses a method for shape and property control in ultrasonic vibration-assisted arc additive manufacturing. This method applies non-contact ultrasonic vibration to the molten pool simultaneously to achieve grain refinement, while the cutting head impacts the cladding layer surface at high frequency to improve the dimensional accuracy of the cladding layer, reduce residual stress, and refine surface grains. However, this patent still has the following problems: 1) The ultrasonic vibration-assisted arc additive manufacturing equipment of this method has a complex structure, cumbersome operation steps, and high learning costs; 2) The strengthening and finishing treatment of the cladding layer surface by the cutting head is performed alternately with the arc additive manufacturing process, resulting in complex procedures and affecting production efficiency.

[0005] Patent CN111590189A discloses a welding additive manufacturing ultrasonic impact device and its operating method. This method applies welding impact to additive manufacturing to release stress and refine grains. It also reduces friction and sway of the ultrasonic transducer during welding, thus stabilizing the ultrasonic processing. However, this patent has a drawback: it uses a unidirectional stacking method. Because the arc-extinguishing end is slightly lower than the intermediate stable section, and this difference gradually amplifies as the number of stacked layers increases, it can affect the stability of the additive manufacturing process and even lead to collapse at the arc-extinguishing point. Summary of the Invention

[0006] Objective of the Invention: To address the technical problems in existing arc additive manufacturing, such as residual stress accumulation leading to warping and deformation of the formed parts, resulting in reduced performance, and changes in heat accumulation causing weld edge "collapse," which limit the number of layers and height of the additively formed parts, this invention provides an ultrasonic impact-ultrasonic field-assisted plasma arc additive manufacturing device. This device directly applies ultrasonic vibration from a tungsten electrode to the plasma arc and the molten pool, promoting the fluidity of the molten pool metal, breaking down and refining the grains. Simultaneously, an ultrasonic impact device is used to perform surface treatment on the newly formed, softened portion, causing plastic deformation and improving the dimensional accuracy of the cladding layer. Furthermore, it can reduce residual stress and refine the grains. In addition, this invention also provides a processing method for this device.

[0007] Technical solution: The ultrasonic impact-ultrasonic field assisted plasma arc additive manufacturing device of the present invention includes a plasma arc additive manufacturing device, an ultrasonic auxiliary device, a first robotic arm, an ultrasonic impact device, a positioning fixture, and a second robotic arm; the plasma arc additive manufacturing device is fixedly connected to the ultrasonic auxiliary device, the plasma arc additive manufacturing device is installed on the first robotic arm, and the second robotic arm is connected to the ultrasonic impact device through the positioning fixture.

[0008] Furthermore, the plasma arc additive manufacturing apparatus includes a plasma welding machine, a welding torch, a wire feeder, a gas cylinder, and a worktable. The gas cylinder, plasma welding machine, welding torch, and wire feeder are connected in sequence, and the worktable is located directly below the welding torch. The welding torch includes a torch shell, an ion gas delivery pipe, a protective gas delivery pipe, a water inlet pipe, a water outlet pipe, a tungsten electrode, and a nozzle.

[0009] Furthermore, the ultrasonic-assisted device includes an ultrasonic generator, a transducer, an amplitude transformer, a coupling connector, and a fixing device connected in sequence. The ultrasonic-assisted device is connected to the welding torch through the fixing device, and the amplitude transformer is connected to the tungsten electrode through the coupling connector. This ensures the assembly accuracy of the welding torch and the alignment of the tungsten electrode, improving the stability of the coaxial ultrasonic-assisted plasma additive manufacturing process. The entire assembly of the transducer and amplitude transformer is called an ultrasonic transducer. The coupling connector then firmly connects the amplitude transformer and the tungsten electrode into a single unit, forming an ultrasonic vibration system.

[0010] The working principle of the ultrasonic auxiliary device is as follows: electrical energy is converted into mechanical energy in the form of ultrasonic vibration through a transducer, and then the ultrasonic vibration is amplified by an amplitude transformer. It is then transmitted to the tungsten electrode of the plasma welding torch through a coupling connector, and the ultrasonic vibration is introduced into the molten pool through the plasma arc at the end of the tungsten electrode. Under the action of the ultrasonic energy field, the microstructure and fluidity of the molten pool metal change.

[0011] Furthermore, the ultrasonic impact device includes an ultrasonic generator, an impact head, and a pressure regulating chamber connected in sequence. The pressure regulating chamber contains a constant force device, a slide table, and a slide rail. The constant force device includes a support, a spindle, a constant force spring, and ball bearings. The constant force device and the impact head are fixed to both sides of the slide table. The constant force spring is an Archimedean spiral type with a short preload stroke. After elongation exceeds the preload stroke, it maintains a constant elastic force throughout the entire stroke, providing a constant preset pressure for the ultrasonic impact device and also allowing the impact head to reset. The constant force device can provide different preset pressures to the ultrasonic impact device by replacing the constant force spring. The pressure regulating chamber is clamped in a positioning fixture, and the impact head is moved by a second robotic arm, which controls the movement trajectory of the impact head. The relative position of the pressure regulating chamber and the impact head is controlled by vertical displacement, thereby controlling the constant force spring to elongate beyond the preload stroke and providing a stable preset pressure for the ultrasonic impact device.

[0012] Furthermore, the positioning fixture includes a fixing device, a base, a movable fixture, a guide shaft, a positioning spring, and a positioning bolt. The positioning fixture adjusts and fixes the relative positions of the two movable fixtures through the positioning bolt and the positioning spring, and a scale ensures the adjustment accuracy, which can ensure the balance and stability of the positioning fixture, improve the stability of the ultrasonic impact process, and the positioning fixture can precisely adjust and fix the relative position of the ultrasonic impact device, enabling welding impact and repeated high-frequency impact on the surface of each newly formed and softened cladding layer. This not only improves work efficiency, but also improves the dimensional accuracy of the additively formed parts, reduces residual stress, and improves mechanical properties.

[0013] The processing method of the ultrasonic shock-ultrasonic field-assisted plasma arc additive manufacturing device of the present invention includes the following steps:

[0014] 1) Preliminary installation: First, the plasma arc additive manufacturing device and ultrasonic auxiliary device are set up, then the welding torch and the first robotic arm are installed, and finally the ultrasonic impact device, positioning fixture and the second robotic arm are installed, thus completing the installation of the ultrasonic impact-ultrasonic field assisted plasma arc additive manufacturing device.

[0015] 2) Debugging: Adjust the relative position and angle of the impact head and the welding gun to keep them on the same straight line, turn on the device, input the trajectory program into the controller that controls the first and second robotic arms, and complete the debugging;

[0016] 3) Coaxial ultrasonic-assisted additive manufacturing: Set process parameters, and the ultrasonic-assisted device and the plasma arc additive manufacturing device work simultaneously. The ultrasonic transducer introduces ultrasonic vibration into the plasma arc and the molten pool. The first robotic arm controls the welding torch to perform additive manufacturing according to the preset additive trajectory.

[0017] 4) Ultrasonic impact: Set the ultrasonic parameters, and simultaneously turn on the ultrasonic impact device and the plasma arc additive manufacturing device. The second robotic arm makes the ultrasonic impact device move on both sides of the welding torch forward direction according to the same trajectory and speed, and repeatedly impact the newly formed and softened cladding layer with high frequency.

[0018] 5) Post-processing: Turn off the device and wait for the additively formed part to cool down. The additive manufacturing process is now complete.

[0019] Furthermore, in step 3), the welding process parameters (welding current, welding speed, ion gas flow rate) and ultrasonic parameters (frequency, amplitude, power) are optimized to achieve coupling matching, so as to ensure that the welding process is stable and efficient and helps to obtain high-quality formed parts.

[0020] Furthermore, in step 3), the coaxial ultrasonic-assisted additive manufacturing can adopt an interleaved stacking method, that is, a welding method of welding back and forth end to end, which can significantly reduce the thickness difference of the cladding layer and improve the dimensional accuracy of the formed part.

[0021] Furthermore, in step 4), the ultrasonic parameters of the ultrasonic impact device are optimized. The impact frequency of the ultrasonic impact device is set to a frequency that can resonate with the metal material through calculation. Through high-frequency impact, the cladding layer undergoes plastic deformation, which can improve the dimensional accuracy of the formed part, release residual stress, and refine the grains.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0023] (1) The ultrasonic-assisted device of the present invention introduces ultrasonic vibration directly from the tungsten electrode to the plasma arc and the molten pool. Under the action of the ultrasonic energy field, the fluidity of the molten pool metal increases, the gas is completely released, the alloying elements are more evenly distributed, and it can break up coarse columnar crystals and refine the grains.

[0024] (2) The ultrasonic impact device of the present invention performs high-frequency impact on the surface of the cladding layer that has just been formed and is in a softened state, so that the surface of each cladding layer undergoes plastic deformation, thereby improving the dimensional accuracy of the additively formed part. In addition, ultrasonic impact can reduce the residual stress of the cladding layer, refine the near-surface grains, and improve the mechanical properties of the additively formed part.

[0025] (3) The positioning fixture of the present invention can precisely adjust and fix the relative position of the ultrasonic impact device, realize the impact during welding, and repeatedly impact the surface of each newly formed and softened cladding layer with high frequency, which not only improves the work efficiency, but also improves the dimensional accuracy of the additively formed parts, reduces residual stress, and improves mechanical properties.

[0026] (4) The constant force device of the present invention utilizes the characteristics of the constant force spring with short preload stroke and constant elastic force throughout the stroke to provide a constant preset pressure for the ultrasonic impact device. Different preset pressures can be provided by replacing the constant force spring. This device can improve the stability of the ultrasonic impact process and is energy-saving and environmentally friendly. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the ultrasonic shock-ultrasonic field assisted plasma arc additive manufacturing apparatus of the present invention;

[0028] Figure 2 This is a schematic diagram of the welding torch of the present invention;

[0029] Figure 3 This is a schematic diagram of the ultrasonic impact device of the present invention;

[0030] Figure 4 This is a schematic diagram of the constant force device of the present invention;

[0031] Figure 5 This is a schematic diagram of the positioning fixture of the present invention;

[0032] In the diagram, 1. Plasma arc additive manufacturing device; 11. Plasma welding machine; 12. Welding torch; 121. Torch shell; 122. Ion gas supply pipe; 123. Shielding gas supply pipe; 124. Water inlet pipe; 125. Water outlet pipe; 126. Tungsten electrode; 127. Nozzle; 13. Wire feeder; 14. Gas tank; 15. Workbench; 2. Ultrasonic auxiliary device; 21. Ultrasonic generator; 22. Transducer; 23. Amplitude bar; 24. Coupling connector; 25. Fixing device; 3. 1. First robotic arm; 4. Ultrasonic impact device, 41. Ultrasonic generator, 42. Pressure regulating chamber, 43. Constant force device, 431. Constant force spring support, 432. Constant force spring spindle, 433. Constant force spring, 434. Ball bearing, 44. Slide table, 45. Slide rail, 46. Impact head; 5. Positioning fixture, 51. Fixing device, 52. Base, 53. Moving fixture, 54. Guide shaft, 55. Positioning spring, 56. Positioning bolt; 6. Second robotic arm. Detailed Implementation

[0033] The present invention will now be further described in conjunction with specific embodiments and accompanying drawings.

[0034] like Figure 1, Figure 2 As shown, the ultrasonic impact-ultrasonic field-assisted plasma arc additive manufacturing apparatus of the present invention consists of a plasma arc additive manufacturing apparatus 1, an ultrasonic auxiliary device 2, a first robotic arm 3, an ultrasonic impact device 4, a positioning fixture 5, and a second robotic arm 6. The plasma arc additive manufacturing apparatus 1 is fixedly connected to the ultrasonic auxiliary device 2, the ultrasonic auxiliary device 2 is mounted on the first robotic arm 3, the first robotic arm 3 is connected to the second robotic arm 6, and the second robotic arm 6 is connected to the ultrasonic impact device 4 through the positioning fixture 5.

[0035] The plasma arc additive manufacturing apparatus 1 includes a plasma welding machine 11, a welding torch 12, a wire feeder 13, a gas tank 14, and a worktable 15. The welding torch 12 includes a torch shell 121, an ion gas delivery pipe 122, a protective gas delivery pipe 123, a water inlet pipe 124, a water outlet pipe 125, a tungsten electrode 126, and a nozzle 127.

[0036] The ultrasonic auxiliary device 2 includes an ultrasonic generator 21, a transducer 22, an amplitude transformer 23, a coupling connector 24, and a fixing device 25. The ultrasonic transducer 22 and the amplitude transformer 23 are connected together to form an ultrasonic transducer. The amplitude transformer 23 and the tungsten electrode 126 are then firmly connected together by the coupling connector 24 to form an ultrasonic vibration system. The ultrasonic vibration system is a key component in realizing the coaxial ultrasonic energy field-assisted plasma additive manufacturing process. Its working principle is to convert electrical energy into mechanical energy in the form of ultrasonic vibration through the transducer 22, and then use the amplitude transformer 23 to amplify the ultrasonic vibration, which is then transmitted to the tungsten electrode 126 of the plasma welding torch 12 through the coupling connector 24. The ultrasonic energy field is introduced into the molten pool through the plasma arc at the end of the tungsten electrode 126, affecting the microstructure and fluidity of the molten pool metal.

[0037] Furthermore, by calculating and finding the node position where the ultrasonic transducer amplitude is zero, this position is set as the fixing device 25. The ultrasonic vibration system is fixed on the welding torch 12 by the fixing device 25 at this node position, which ensures the assembly accuracy of the welding torch 12 and the centering of the tungsten electrode 126, thereby improving the stability of the coaxial ultrasonic-assisted plasma additive manufacturing process.

[0038] like Figures 3 to 5 The ultrasonic impact device 4 includes a pressure regulating chamber 42 and an impact head 46 connected sequentially from top to bottom. The pressure regulating chamber is equipped with a constant force device 43, a slide table 44, and a slide rail 45. The constant force device 43 includes a support 431, a spindle 432, a constant force spring 433, and a ball bearing 434. The ultrasonic generator 41 is connected to the impact head 46. The pressure regulating chamber 42 has a slide rail 45 that cooperates with the slide table 44. The constant force device 43 and the impact head 46 are fixed to two sides of the slide table 44 respectively.

[0039] The positioning fixture 5 includes a fixing device 51, a base 52, a moving fixture 53, a guide shaft 54, a positioning spring 55, and a positioning bolt 56, and has a scale to ensure adjustment accuracy. The positioning fixture 5 has a reserved space in the middle for additive manufacturing of the welding torch, allowing for precise adjustment and fixing of the relative position of the impact head 46 and the welding torch 12, ensuring that the bottom ends of the impact head 46 and the welding torch 12 are on the same horizontal line. This enables welding-as-you-go impact and repeated high-frequency impact on the surface of each newly formed, softened cladding layer, improving work efficiency.

[0040] The positioning clamp 5 holds the pressure regulating chamber 42, which moves up and down via the second robotic arm 6 to adjust the distance between the ultrasonic impact head 46 and the cladding layer surface, thereby adjusting the pressure of the impact head 46 in contact with the cladding layer. When the bottom of the impact head 46 is just in contact with the cladding layer, the pressure between them is zero. At this point, if the pressure regulating chamber 42 continues to move downward, the constant force spring 431 will extend beyond its preload stroke, and the contact pressure between the impact head 46 and the cladding layer will remain constant. If it is necessary to change the preset pressure of the ultrasonic impact device 4 on the cladding layer surface, the constant force spring 431 with a different elasticity can be replaced.

[0041] The ultrasonic impact-ultrasonic field-assisted plasma arc additive manufacturing method described herein uses a plasma arc as a heat source and employs synchronous wire feeding to deposit filler metal onto the substrate surface. The ultrasonic energy field is introduced into the molten pool through the coupling of the amplitude transformer 23 of the ultrasonic auxiliary device 2 and the tungsten electrode 126. Simultaneously, the residual heat from the pre-formed portion during the additive manufacturing process is effectively utilized. The ultrasonic impact device 4 repeatedly performs high-frequency impacts on the newly formed, softened cladding layer surface, which improves additive manufacturing efficiency, effectively enhances the dimensional accuracy of the formed part, reduces residual stress, and refines the grain size, thereby achieving the goal of shape and property control in plasma arc additive manufacturing. The specific steps are as follows:

[0042] 1) Preliminary installation: First, the plasma arc additive manufacturing device 1 and the ultrasonic auxiliary device 2 are assembled. Then, the welding torch 12 and the first robotic arm 3 are installed. Finally, the ultrasonic impact device 4, the positioning fixture 5 and the second robotic arm 6 are installed, thus completing the installation of the ultrasonic impact-ultrasonic field assisted plasma arc additive manufacturing device.

[0043] 2) Debugging: Adjust the relative position and angle of the impact head 46 and the welding torch 12 to keep them on the same straight line, turn on the device, input the trajectory program into the controller that controls the first robotic arm 3 and the second robotic arm 6, and complete the debugging;

[0044] 3) Coaxial ultrasonic-assisted additive manufacturing: Set process parameters, ultrasonic auxiliary device 2 and plasma arc additive manufacturing device 1 work simultaneously, ultrasonic vibration is introduced into plasma arc and molten pool through ultrasonic transducer, and welding torch 12 is controlled by first robotic arm 3 to perform additive manufacturing according to preset additive trajectory;

[0045] 4) Ultrasonic impact: Set ultrasonic parameters, and simultaneously turn on the ultrasonic impact device 4 and the plasma arc additive manufacturing device 1. The second robotic arm 6 controls the ultrasonic impact device 4 to move forward and backward on both sides of the welding torch in the same trajectory and speed, and repeatedly impacts the newly formed and softened cladding layer with high frequency.

[0046] 5) Post-processing: Turn off the device and wait for the additively formed part to cool down. The additive manufacturing process is now complete.

[0047] This embodiment, while ensuring the normal operation of the welding torch 12, designs and modifies it to couple the ultrasonic transducer with the tungsten electrode 126. The ultrasonic vibration is transmitted to the plasma arc via the tungsten electrode 126, allowing for further compression of the plasma arc, increased stiffness, and a more stable additive manufacturing process. Simultaneously, ultrasonic vibration is introduced into the molten pool. Under the influence of the ultrasonic energy field, the fluidity of the molten metal increases, gas precipitation is more complete, alloy element distribution is more uniform, and coarse columnar crystals are broken down, refining the grain size. The circuits of the plasma arc additive manufacturing device 1 and the ultrasonic auxiliary device 2 are separated, allowing for independent parameter adjustment and broadening the range of process parameters for obtaining high-quality formed parts. By optimizing the welding process parameters (welding current, welding speed, ion gas flow rate) and ultrasonic parameters (frequency, amplitude, power), coupling matching is achieved to ensure a stable and efficient welding process, contributing to the acquisition of high-quality formed parts.

[0048] In this embodiment, during plasma arc additive manufacturing, non-contact ultrasonic vibration coaxial with the tungsten electrode is applied to the molten pool, promoting gas precipitation and grain breakage. Simultaneously, the residual heat from the pre-formed portion is effectively utilized, and the surface of the newly formed, softened cladding layer is repeatedly subjected to high-frequency impacts by an ultrasonic impact device 4, causing plastic deformation. This strengthens each cladding layer, improving the dimensional accuracy and mechanical properties of the formed part. Specifically, optimizing the ultrasonic parameters of the ultrasonic impact device, by calculating and setting the impact frequency to a frequency that resonates with the filler metal material, effectively enhances the strengthening effect of ultrasonic impact on the cladding layer.

Claims

1. An ultrasonic impact-ultrasonic field-assisted plasma arc additive manufacturing apparatus, characterized in that, The system includes a plasma arc additive manufacturing device (1), an ultrasonic auxiliary device (2), a first robotic arm (3), an ultrasonic impact device (4), a positioning fixture (5), and a second robotic arm (6). The plasma arc additive manufacturing device (1) is fixedly connected to the ultrasonic auxiliary device (2), and the plasma arc additive manufacturing device (1) is installed on the first robotic arm (3). The second robotic arm (6) is connected to the ultrasonic impact device (4) through the positioning fixture (5). The plasma arc additive manufacturing device (1) includes a plasma welding machine (11), a welding torch (12), a wire feeder (13), a gas tank (14), and a worktable (15). The gas tank (14), the plasma welding machine (11), the welding torch (12), and the wire feeder (13) are connected in sequence. A first robotic arm (3) and a second robotic arm (6) are respectively installed above the worktable (15); the ultrasonic auxiliary device (2) includes an ultrasonic generator (21), a transducer (22), an amplitude transformer (23), a coupling connector (24), and a fixing device (25) connected in sequence; the ultrasonic auxiliary device (2) is connected to the welding torch (12) through the fixing device (25), and the amplitude transformer (23) is coupled to the tungsten electrode (126) through the coupling connector (24), so that the ultrasonic energy field is introduced from the tungsten electrode (126) into the plasma arc and the molten pool, realizing coaxial ultrasonic-assisted plasma arc additive manufacturing; the ultrasonic impact device (4) includes an ultrasonic generator (41), an impact head (46), and a pressure regulating chamber connected in sequence. (42) The pressure regulating chamber (42) is equipped with a constant force device (43), a slide table (44) and a slide rail (45). The constant force device (43) includes a support (431), a spindle (432), a constant force spring (433) and a ball bearing (434). The constant force device (43) and the impact head (46) are fixed to the two sides of the slide table (44) respectively. The pressure regulating chamber (42) is clamped in the positioning fixture (5) and the impact head (46) is moved by the second mechanical arm (6). The positioning fixture (5) includes a fixing device (51), a base (52), a moving fixture (53), a guide shaft (54), a positioning spring (55) and a positioning bolt (56). The positioning fixture (5) contains Space is reserved between the welding torch for additive manufacturing. The positioning fixture (5) can precisely adjust and fix the relative position of the impact head (46) and the welding torch (12). The positioning fixture (5) holds the pressure regulating chamber (42) and moves up and down through the second robotic arm (6) to adjust the distance between the ultrasonic impact head (46) and the surface of the cladding layer, thereby adjusting the pressure of the impact head (46) in contact with the cladding layer. When the bottom of the impact head (46) is in contact with the cladding layer, the pressure between the two is zero. At this time, the pressure regulating chamber (42) continues to move downward. After the constant force spring (433) stretches beyond the preload stroke, the contact pressure between the impact head (46) and the cladding layer is constant. Ultrasonic impact devices (4) are provided on both sides along the forward direction of the welding torch.During the ultrasonic impact step, ultrasonic parameters are set, and the ultrasonic impact device (4) is simultaneously activated with the plasma arc additive manufacturing device (1). The second robotic arm (6) controls the ultrasonic impact device (4) to move along the front and rear sides of the welding torch's forward direction along the same trajectory and speed, repeatedly subjecting the newly formed, softened cladding layer to high-frequency impacts.

2. The manufacturing apparatus according to claim 1, characterized in that, The welding torch (12) includes a torch body shell (121), an ion gas delivery pipe (122), a protective gas delivery pipe (123), a water inlet pipe (124), a water outlet pipe (125), a tungsten electrode (126), and a nozzle (127).

3. The manufacturing apparatus according to claim 1, characterized in that, The constant force spring (433) is an Archimedean spiral type, which provides constant pressure to the impact head (46).

4. A processing method for the ultrasonic shock-ultrasonic field-assisted plasma arc additive manufacturing apparatus according to claim 1, characterized in that, Includes the following steps: 1) Preliminary installation: First, the plasma arc additive manufacturing device (1) and the ultrasonic auxiliary device (2) are built, then the welding torch (12) and the first robotic arm (3) are installed, and finally the ultrasonic impact device (4), the positioning fixture (5) and the second robotic arm (6) are installed, thus completing the installation of the ultrasonic impact-ultrasonic field assisted plasma arc additive manufacturing device. 2) Debugging: Adjust the relative position and angle of the impact head (46) and the welding gun (12) to keep them on the same straight line, turn on the device, input the trajectory program into the controller that controls the first robotic arm (3) and the second robotic arm (6) to complete the debugging; 3) Coaxial ultrasonic-assisted additive manufacturing: Set process parameters, the ultrasonic-assisted device (2) and the plasma arc additive manufacturing device (1) work simultaneously, the ultrasonic vibration is introduced into the plasma arc and the molten pool through the ultrasonic transducer, and the welding gun (12) is controlled by the first robotic arm (3) to carry out additive manufacturing according to the preset additive trajectory; 4) Ultrasonic impact: Set ultrasonic parameters, and simultaneously turn on the ultrasonic impact device (4) and the plasma arc additive manufacturing device (1). Control the ultrasonic impact device (4) to move along the front and rear sides of the welding torch forward direction according to the same trajectory and movement speed through the second robotic arm (6) to repeatedly impact the newly formed, softened cladding layer with high frequency. 5) Post-processing: Turn off the device and wait for the additively formed part to cool down. The additive manufacturing process is now complete.

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