Plasma arc additive manufacturing device and method based on wire powder coaxiality

Abstract

The invention discloses a plasma arc additive manufacturing device and method based on wire and powder coaxiality, and belongs to the field of arc additive manufacturing. The device comprises a multi-wire powder coaxial welding gun; the welding gun comprises a copper nozzle, a welding gun shell and a powder feeding shell, an ion gas port is formed in the middle of the copper nozzle, wire feeding ports are formed in the front end and the rear end of an ion gas outlet, and powder feeding ports are formed in the left end and the right end of the ion gas outlet; the wire powder coaxial copper nozzle is located at the bottom end of the plasma arc welding gun and connected with the welding gun shell. A second channel between the ion gas shell and the powder feeding shell is used for feeding powder; through holes are formed in the surfaces of the two sides of the welding gun shell and the powder feeding shell correspondingly and used for feeding welding wires, and the welding wires are fed into the wire feeding opening through the second channel. According to the device, the wire feeding channel and the powder feeding channel are coaxially integrated, and metal wires and metal powder are ensured to be melted and deposited in the plasma arc center by accurately controlling the conveying paths of the two materials.

Description

Technical Field

[0001] The present invention belongs to the field of arc additive manufacturing, and in particular relates to a plasma arc additive manufacturing device and method based on silk-powder coaxiality. Background Art

[0002] Arc additive manufacturing is an efficient and low-cost additive manufacturing technology. Due to its high deposition rate and ability to adapt to the manufacturing of large-sized structural parts, it has gradually become one of the preferred technologies for the manufacture of large-scale metal components in the industrial field. The existing arc additive manufacturing technology mainly uses metal wire as the wire feeding material, melts the metal wire through the arc and accumulates it layer by layer to form parts. However, the additive manufacturing method that only uses metal wire as the raw material has problems such as single material selection and difficult to control the alloy composition, which limits its flexibility and diversity in certain specific applications. At the same time, metal powder additive manufacturing technology is more flexible in the selection of material types, but its deposition efficiency is relatively low, and the cost of laser equipment is high. Therefore, a plasma arc additive manufacturing technology based on wire-powder coaxial is proposed. This technology introduces metal wire and metal powder into the plasma arc at the same time to achieve synchronous melting and deposition of the two materials, which can not only effectively improve the efficiency of additive manufacturing, but also flexibly control the material composition, and further optimize the mechanical properties and microstructure of parts during the manufacturing process.

[0003] Patent CN113385778A adopts the method of hollow tungsten electrode wire feeding-laser cladding powder feeding to realize wire-powder coaxial plasma arc additive manufacturing, but the hollow tungsten electrode is difficult to prepare and easy to burn. The wire-powder coaxial strategy adopted in this study is to add a coaxial powder feeding channel and a wire feeding channel next to the tungsten electrode, which is easy to realize large-scale production application. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a plasma arc additive manufacturing device and method based on wire-powder coaxiality, which integrates the welding wire, powder and tungsten electrode into one welding gun, and the powder and welding wire are coaxially fed into the plasma. Compared with side-axis powder feeding, coaxial powder feeding avoids the interference of the arc blowing force on the powder. Compared with side-axis wire feeding, coaxial wire feeding improves the melting efficiency of the welding wire. The melting efficiency of the welding wire is lower than that of the powder. This method realizes the synchronous melting and deposition of the wire powder, which not only improves the efficiency of additive manufacturing, but also has the flexibility to regulate the material composition, thereby optimizing the mechanical properties and microstructure of the product.

[0005] The present invention provides a plasma wire-powder coaxial composite welding gun, comprising a tungsten pole, a wire-powder coaxial copper nozzle, a sleeve, an ion gas housing, a powder feeding housing, and a welding gun housing;

[0006] An ion gas outlet is provided in the middle of the silk-powder coaxial copper nozzle; a powder feeding port is arranged at one end of the ion gas outlet, and a wire feeding port is arranged at the other end of the ion gas outlet; a shielding gas outlet is provided on the outer side of the silk-powder coaxial copper nozzle; the silk-powder coaxial copper nozzle is located at the bottom end of the silk-powder coaxial composite welding gun and is connected to the welding gun housing;

[0007] A powder feeding shell is nested inside the shell of the silk-powder coaxial composite welding gun, and the third channel between the powder feeding shell and the welding gun shell is used to inject shielding gas; an ion gas shell is nested inside the powder feeding shell, and the second channel between the ion gas shell and the powder feeding shell is used to inject powder and welding wire, the second channel located at one end of the powder feeding port is used to transport powder, and the second channel located at one end of the wire feeding port is used to transport welding wire; the first channel inside the ion gas shell is used to inject ion gas; the ion gas shell is an internal hollow structure for injecting cooling water; the welding gun shell and the powder feeding shell are provided with through holes, and the through holes are used to feed welding wire, and the welding wire is fed into the wire feeding port through the second channel; a sleeve is arranged on the outside of the tungsten electrode, and the sleeve is located in the ion gas shell.

[0008] Furthermore, the sleeve is made of a non-conductive and high temperature resistant material.

[0009] Furthermore, the second channel of the wire-powder coaxial composite welding gun is provided with a partition plate for separating the left and right ends, and the second channels for conveying the welding wire and the powder are independent of each other.

[0010] Furthermore, the diameter of the ion gas outlet of the silk-powder coaxial copper nozzle is 4.5-5.5 mm; the diameter of the powder feeding port is 1.2-1.5 mm; and the diameter of the wire feeding port is 2-3 mm.

[0011] Furthermore, the angle between the welding wire feeding port and the tungsten electrode is 30° to 45°; the angle between the powder feeding port and the tungsten electrode is 30° to 45°.

[0012] The present invention further provides a silk powder coaxial plasma arc additive manufacturing device, comprising a plasma silk powder coaxial composite welding gun and a silk powder coaxial welding power supply; the positive pole of the silk powder coaxial welding power supply is connected to the tungsten pole, and the negative pole is connected to the substrate; the ion gas shell is connected to the cooling water mechanism; the first channel of the silk powder coaxial welding gun is connected to the ion gas supply system; a powder feeding mechanism is arranged on the top surface of one end of the silk powder coaxial welding gun, and the powder feeding mechanism is connected to the second channel, and the powder is fed into the powder feeding port through the airflow; the third channel of the silk powder coaxial composite welding gun is connected to the protective gas system; a wire feeding mechanism is arranged at the other end of the silk powder coaxial composite welding gun, and the wire feeding mechanism is located at the top end of the welding wire; the welding wire passes through the welding gun shell and the powder feeding shell from the outside to the inside, enters the second channel and is fed out through the wire feeding port.

[0013] The present invention further provides a method for manufacturing a plasma arc additive manufacturing device based on silk powder coaxiality, comprising the following steps:

[0014] Step 1: fix the pre-treated substrate on the additive manufacturing workbench and connect the silk-powder coaxial plasma arc additive manufacturing device; install the silk-powder coaxial composite welding gun above the substrate;

[0015] Step 2: Select appropriate welding wire and powder according to the requirements of the target part; set the process parameters of the wire-powder coaxial plasma arc additive manufacturing device according to the geometric structure and material composition distribution of the target part;

[0016] Step 3: Turn on the ion supply system and the shielding gas system, and adjust the flow of the ion gas supply system and the shielding gas system to form a stable protective atmosphere; turn on the cooling water mechanism, and start the silk-powder coaxial composite welding gun; start the powder feeding mechanism and the wire feeding mechanism at the same time, and the welding wire in the wire feeding mechanism and the powder in the powder feeding mechanism are transported synchronously; the silk-powder coaxial composite welding gun generates a high-temperature plasma arc, and the welding wire and powder are melted at the same time and deposited on the substrate, and the target parts are stacked layer by layer.

[0017] Step 4: Turn on the wire feeding mechanism and the powder feeding mechanism to feed the welding wire and powder into the plasma arc at the same time. The welding wire and powder are melted synchronously and then deposited on the substrate to build the target part layer by layer.

[0018] Furthermore, the distance between the silk powder coaxial copper nozzle of the silk powder coaxial composite welding gun and the upper surface of the substrate is 5 to 6 mm;

[0019] Furthermore, in step 2, the diameter of the welding wire is 1.2 mm, and the welding wire is a metal wire; the diameter of the powder is 5 to 50 μm, and the powder is a metal powder.

[0020] Furthermore, in step 3, the welding process parameters are set according to actual conditions, the welding current is 50-100A, the welding voltage is 15-22V, the wire feeding speed is 1-5m / min, and the powder feeding speed is 1-10g / min; the powder feeding argon gas flow rate is 5-8L / min, the ion gas flow rate of the ion gas supply system is 0.5-1L / min, and the shielding gas flow rate of the shielding gas system is 5-10L / min.

[0021] The beneficial effects of the present invention are:

[0022] (1) The wire-powder coaxial plasma arc welding gun of the present invention has a reasonable structural design, and the wire feeding channel and the powder feeding channel are coaxially integrated. By precisely controlling the conveying paths of the two materials, it is ensured that the metal wire and the metal powder are melted and deposited in the center of the plasma arc. In this coaxial powder feeding device, the powder is fed into the heel of the arc and blown into the molten pool along with the arc, thus avoiding the problem of powder deviation and loss caused by the arc blowing force in traditional side-axis powder feeding. In this coaxial wire feeding device, the melting efficiency of the welding wire is greatly improved, and the problem of uneven melting of the wire powder caused by the lower melting efficiency of the welding wire than the powder is solved. In addition, the structure simplifies the design of the welding gun, reduces the size and complexity of the equipment, improves the reliability and applicability of the system, and is conducive to the efficient additive manufacturing of a variety of materials.

[0023] (2) The present invention introduces the wire powder coaxial feeding technology for the first time in arc additive manufacturing, breaking through the bottleneck of arc additive manufacturing's traditional single material selection and difficult to control alloy composition. Compared with laser additive manufacturing, arc additive equipment has low cost and high energy utilization, and is suitable for larger-scale and low-cost manufacturing needs. By using both metal powder and metal wire as raw materials, precise control of alloy composition is achieved, which provides flexibility in material selection and diversity in process, opens up a new direction for arc additive manufacturing, and further enhances its competitiveness and application potential in the preparation of complex functional components. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of a plasma arc additive manufacturing device based on silk powder coaxiality of the present invention;

[0025] Figure 2 The Al-4.5Mg-15Bi high wear-resistant alloy for bearings is prepared by the silk-powder coaxial plasma arc additive manufacturing device of the present invention.

[0026] Among them: 1-argon powder feeder, 2-cooling water tank, 3-tungsten electrode, 4-ion gas, 5-shielding gas, 6-ceramic sleeve, 7 wire feeder, 8-welding wire, 9-copper nozzle, 10-powder feeding port, 11-powder, 12-wire feeding port, 13-shielding gas outlet, 14-ion gas outlet, 15-connecting parts, 16-welding gun housing. DETAILED DESCRIPTION

[0027] In order to facilitate the understanding of those skilled in the art, the present invention is further described in detail below with reference to the accompanying drawings and implementation cases, which is intended to help understand the technical solution of the present invention, but does not limit the protection scope of the present invention.

[0028] The present invention provides a plasma arc additive manufacturing device based on wire-powder coaxiality, including a plasma arc power supply, a cooling water mechanism, a plasma welding gun, an air supply device, a wire feeding mechanism, a powder feeding mechanism, and a wire-powder coaxial welding gun. The plasma power supply generates a stable high-temperature electric arc for melting metal wire and metal powder; the wire feeding mechanism and the powder feeding mechanism are respectively used to coaxially feed the metal wire and the metal powder into the plasma arc to ensure that the two materials are melted and deposited at the same time; the wire-powder coaxial welding gun is used to accurately control the conveying path of the metal wire and the metal powder to ensure uniform melting and deposition of the material. The cooling water mechanism is used to protect the copper nozzle to prevent the copper nozzle from burning under high-temperature plasma. In addition, a control system is also provided for adjusting process parameters such as the power, wire feeding speed, and powder feeding speed of the plasma arc to meet the manufacturing requirements of different materials and parts.

[0029] The manufacturing method of the present invention comprises the following steps:

[0030] (1) Material preparation: Select appropriate metal wire and metal powder according to the requirements of the target part. Metal wire is usually used to provide structural strength, while metal powder is used to regulate the composition and performance of the part.

[0031] (2) Process parameter setting: According to different material types and workpiece requirements, set the plasma arc power, wire feeding speed, powder feeding speed, deposition path and other process parameters to ensure that the metal wire and metal powder are melted and deposited at the appropriate temperature and speed.

[0032] (3) Synchronous melting and deposition: The metal wire and metal powder are fed into the plasma arc simultaneously through the wire feeding mechanism and the powder feeding mechanism, so that the two are melted synchronously and then deposited on the substrate to build the target part layer by layer. By adjusting the powder feeding ratio, the alloy composition and microstructure of the control part can be flexibly adjusted.

[0033] Combined with Figure 1 The present invention provides a plasma arc multi-wire powder coaxial feeding device for additive manufacturing of high entropy alloys. The device has a compact structure and has the characteristics of accurate wire feeding and powder feeding and stable melting control. The device mainly consists of an argon powder feeder 1, a cooling water tank 2, a tungsten electrode 3, an ion gas 4, a shielding gas 5, a ceramic sleeve 6, a wire feeder 7, a welding wire 8, a copper nozzle 9, a powder feeding port 10, powder 11, a wire feeding port 12, a shielding gas outlet 13, an ion gas outlet 14, a welding gun housing 16, etc.

[0034] The welding gun housing 16 serves as the framework of the entire system, and is used to support and protect the key components inside, ensuring that the device operates safely under high temperature and high pressure environments. The welding gun housing material must have strong heat resistance and corrosion resistance.

[0035] The argon powder feeder 1 conveys the powder 11 to the powder feeding port 10 through the argon flow. Argon has good inertness, which can effectively prevent oxidation reactions at high temperatures and ensure that the powder enters the molten pool evenly. The powder feeding angle is between 30 and 45 degrees to ensure that the powder is fed into the center of the arc. At the same time, the wire feeding angle is also between 30 and 45 degrees to ensure that the welding wire is fed into the center of the arc. In addition, the wire feeding angle and the powder feeding angle are the same, which helps the wire and powder to enter the molten pool at the same time. The cooling water tank 2 is used to provide cooling for the welding gun and key components to prevent the device from overheating during operation and extend the service life of the equipment.

[0036] The tungsten electrode 3 is the core component for generating a plasma arc. Under the action of the ion gas 4, a high-temperature arc is formed to melt the welding wire 8 and the powder 11. The ion gas 4 is delivered to the working area through the ion gas outlet 14 of the copper nozzle 9, and the shielding gas 5 is delivered to the working area from the shielding gas outlet 13 of the copper nozzle 9. The diameter of the ion gas outlet is the inner diameter of the copper nozzle 9. The ion gas 4 is used to stabilize the arc. The control of the plasma gas flow rate is very important. The gas flow rate is controlled at 0.5 to 1 L / min to ensure that the powder 11 is stably delivered and will not be blown away due to excessive airflow. The shielding gas 5 is used to protect the molten pool. The gas flow rate is 10 to 20 L / min to prevent the oxygen and nitrogen in the environment from reacting adversely with the metal.

[0037] The ceramic sleeve 6 is located at the outermost layer of the welding gun, and is used to protect the tungsten electrode and gas flow channel in the welding gun, and prevent the welding gun from being damaged by spatter. The wire feeder 7 accurately controls the feeding speed of the welding wire 8, and introduces the welding wire 8 into the molten pool through the wire feed port 12, ensuring that the welding wire 8 and the powder 11 enter the molten pool coaxially to achieve uniform melting.

[0038] The diameter of the shielding gas outlet 13 is 1-1.5 mm, the diameter of the ion gas outlet 14 is 4.5-5.5 mm, the diameter of the powder feeding port 10 is 1.2-1.5 mm, and the diameter of the wire feeding port 12 is 2-3 mm.

[0039] The present invention further discloses a plasma arc additive manufacturing device based on silk powder coaxiality, and the use steps are as follows:

[0040] 1. Equipment preparation: Check the tightness of the welding gun housing 16, ensure that there is enough cooling water in the cooling water tank 2, and the tungsten electrode 3 is clean and intact.

[0041] 2. Material preparation: Select appropriate welding wire 8 and powder 11 as needed, and load them through wire feeder 7 and argon powder feeder 1. Adjust the air flow rate to ensure smooth powder and wire feeding.

[0042] 3. Operation steps: Start the plasma arc, generate a high-temperature arc through the tungsten electrode 3, adjust the flow of ion gas 4 and shielding gas 5 to form a stable protective atmosphere to prevent contamination of the molten pool. At the same time, the wire feeder 7 and the argon powder feeder 1 accurately control the feeding of the welding wire 8 and powder 11.

[0043] 4. Melting and deposition: The wire and powder are fed into the molten pool at the same time, and are melted layer by layer under the action of the electric arc to perform additive manufacturing.

[0044] The following detailed description of the silk powder coaxial plasma arc additive manufacturing device and method of the present invention is combined with embodiments to help understand the technical solution of the present invention, but does not limit the protection scope of the present invention.

[0045] Example 1

[0046] The Al-4.5Mg-20Bi alloy is prepared by using the device of the present invention to make a wear-resistant bearing material having lubricity

[0047] Al-4.5Mg-20Bi alloy is an excellent bearing material. This is because the aluminum-magnesium alloy is light in weight and has good corrosion resistance. Since the melting point of Bi is only 271.3°C, the addition of Bi (bismuth) can form uniformly distributed hard particles or lubricating phases in the matrix, significantly improving the wear resistance of the alloy and reducing the wear of the bearing. At the same time, Bi's low shear strength and good self-lubricating properties enable the alloy to reduce the friction coefficient during sliding and improve the working efficiency of the bearing. However, the boiling point of Bi is only 1564°C and the Bi powder is light in weight. In the traditional side-axis powder feeding process, the arc blowing force will blow away the low-density Bi. At the same time, part of the Bi powder will reach the boiling point at the edge of the arc before entering the center of the arc, and vaporize and volatilize. The silk powder coaxial additive manufacturing device in this study can directly feed the Bi powder into the center of the arc and directly enter the molten pool with the arc, minimizing the powder loss. The specific preparation steps are as follows:

[0048] 1. Material preparation and pre-welding parameter setting

[0049] According to the predetermined part design requirements, suitable metal wire and metal powder are selected as raw materials for additive manufacturing. In this embodiment, aluminum alloy wire (such as Al-4.5Mg alloy) is selected as the main matrix material, and an appropriate amount of Bi powder is selected as the powder raw material, and the powder diameter is between 5μm and 50μm.

[0050] Plasma power supply power: set to 50 ~ 80A to ensure that the aluminum alloy wire and Bi powder can be melted at the same time.

[0051] Wire feeding speed: set to 3m / min, that is, the wire feeding mass is 8.4g / min, ensuring that the aluminum alloy wire can be continuously and stably fed into the plasma arc zone and completely melted.

[0052] Powder feeding speed: The powder is fed into the plasma arc through argon gas. According to the mass ratio of Al-4.5Mg welding wire and Bi powder of 4:1, the powder feeding speed is matched to 2.1g / min.

[0053] Powder feeding gas flow rate: Argon gas flow rate is 5-8L / min, which is suitable for common powder feeding systems. It can effectively transport Bi powder and avoid powder loss or excessive flow causing blowing away from the molten pool. During the experiment, the powder can be started from 4L / min and gradually adjusted to observe whether the powder feeding is stable and whether there is powder accumulation or dispersion in the molten pool.

[0054] Nozzle spacing: Set the height of the nozzle from the substrate to 5-6 mm to ensure the stability and uniform deposition of the molten pool.

[0055] Plasma gas flow rate: set to 0.5~1L / min to ensure stable burning of plasma arc.

[0056] Shielding gas flow rate: set to 5-10L / min. The shielding gas flow rate does not need to be too large, because the powder delivery gas is also argon, which has a certain protective effect.

[0057] 2. Manufacturing steps

[0058] (1) Substrate preparation: The pre-cleaned aluminum alloy substrate is fixed on the AM workbench to ensure that the surface is flat and free of contamination.

[0059] (2) Coaxial wire feeding and powder feeding: The plasma arc generator is started through the control system to generate a high-temperature plasma arc. The wire feeding mechanism and the powder feeding mechanism are started to synchronously feed the Al-4.5Mg alloy wire and Bi powder into the arc zone. Under the action of the high-temperature plasma arc, a molten pool is formed and accumulated layer by layer.

[0060] (3) Layered manufacturing: According to the designed path, the nozzle is controlled to move on the substrate, and the parts are deposited layer by layer until the part is completed. During the deposition of each layer, the stability of the molten pool is monitored and necessary parameters are adjusted to ensure uniform material deposition and the quality of part formation.

[0061] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0062] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A plasma wire-powder coaxial composite welding gun, characterized in that: It comprises a tungsten electrode (3), a wire powder coaxial copper nozzle (9), a sleeve (6), an ion gas housing, a powder delivery housing, and a welding gun housing; An ion gas outlet (14) is provided in the middle of the silk-powder coaxial copper nozzle (9); a powder feeding port (10) is arranged at one end of the ion gas outlet (14), and a wire feeding port (12) is arranged at the other end of the ion gas outlet (14); a shielding gas outlet (13) is provided on the outer side of the silk-powder coaxial copper nozzle; the silk-powder coaxial copper nozzle (9) is located at the bottom end of the silk-powder coaxial composite welding gun and is connected to the welding gun housing; A powder feeding shell is nested inside the shell of the silk-powder coaxial composite welding gun, and a third channel between the powder feeding shell and the welding gun shell is used to inject shielding gas; an ion gas shell is nested inside the powder feeding shell, and a second channel between the ion gas shell and the powder feeding shell is used to inject powder and welding wire, a second channel located at one end of the powder feeding port (10) is used to transport powder, and a second channel located at one end of the wire feeding port (12) is used to transport welding wire; a first channel inside the ion gas shell is used to inject ion gas; the ion gas shell is an internal hollow structure for injecting cooling water; the welding gun shell and the powder feeding shell are provided with through holes, the through holes are used to feed welding wire, and the welding wire is fed into the wire feeding port (12) through the second channel; a sleeve (6) is arranged outside the tungsten electrode (3), and the sleeve (6) is located inside the ion gas shell.

2. The plasma wire-powder coaxial composite welding gun according to claim 1, characterized in that: The sleeve (6) is made of a non-conductive and high temperature resistant material.

3. The plasma wire-powder coaxial composite welding gun according to claim 1, characterized in that: The second channel of the silk-powder coaxial composite welding gun is provided with a partition plate for separating the left and right ends.

4. The plasma wire-powder coaxial composite welding gun according to claim 1, characterized in that: The diameter of the ion gas outlet (14) of the silk-powder coaxial copper nozzle (9) is 4.5-5.5 mm; the diameter of the powder feeding port (10) is 1.2-1.5 mm; and the diameter of the wire feeding port (12) is 2-3 mm.

5. The plasma wire-powder coaxial composite welding gun according to claim 1, characterized in that: The angle between the welding wire feeding port (12) and the tungsten electrode (3) is 30° to 45°; the angle between the powder feeding port (10) and the tungsten electrode (3) is 30° to 45°.

6. A silk powder coaxial plasma arc additive manufacturing device using the silk powder coaxial composite welding gun according to any one of claims 1 to 5, characterized in that: It also includes a wire powder coaxial welding power supply; the positive electrode of the wire powder coaxial welding power supply is connected to the tungsten electrode (3), and the negative electrode is connected to the substrate; the ion gas shell is connected to the cooling water mechanism; the first channel of the wire powder coaxial welding gun is connected to the ion gas supply system; a powder feeding mechanism is arranged on the top surface of one end of the wire powder coaxial welding gun, and the powder feeding mechanism is connected to the second channel, and the powder is fed into the powder feeding port through the airflow; the third channel of the wire powder coaxial composite welding gun is connected to the protective gas system; the other end of the wire powder coaxial composite welding gun is arranged with a wire feeding mechanism, and the wire feeding mechanism is located at the top end of the welding wire; the welding wire passes through the welding gun shell and the powder feeding shell from the outside to the inside, enters the second channel and is fed out through the wire feeding port (12).

7. A manufacturing method using the silk powder coaxial plasma arc additive manufacturing device according to claim 6, characterized in that: The following steps are involved: Step 1: Fix the pre-treated substrate on the additive manufacturing workbench and connect the silk-powder coaxial plasma arc additive manufacturing device; install the silk-powder coaxial composite welding gun above the substrate; Step 2: Select appropriate welding wire and powder according to the requirements of the target part; set the process parameters of the wire-powder coaxial plasma arc additive manufacturing device according to the geometric structure and material composition distribution of the target part; Step 3: Turn on the ion supply system and the shielding gas system, and adjust the flow of the ion gas supply system and the shielding gas system to form a stable protective atmosphere; turn on the cooling water mechanism, and start the silk-powder coaxial composite welding gun; start the powder feeding mechanism and the wire feeding mechanism at the same time, and the welding wire in the wire feeding mechanism and the powder in the powder feeding mechanism are transported synchronously; the silk-powder coaxial composite welding gun generates a high-temperature plasma arc, and the welding wire and powder are melted at the same time and deposited on the substrate, and the target parts are stacked layer by layer. Step 4: Turn on the wire feeding mechanism and the powder feeding mechanism to feed the welding wire and powder into the plasma arc at the same time. The welding wire and powder are melted synchronously and then deposited on the substrate to build the target part layer by layer.

8. The plasma arc additive manufacturing method based on silk powder coaxial manufacturing according to claim 7, characterized in that: The distance between the silk powder coaxial copper nozzle of the silk powder coaxial composite welding gun and the upper surface of the substrate is 5 to 6 mm.

9. The plasma arc additive manufacturing method based on silk powder coaxial manufacturing according to claim 7, characterized in that: In the step 2, the diameter of the welding wire is 1.2 mm, and the welding wire is a metal wire; the diameter of the powder is 5 to 50 μm, and the powder is a metal powder.

10. The plasma arc additive manufacturing method based on silk powder coaxial manufacturing according to claim 7, characterized in that: In step 3, the welding process parameters are set according to actual conditions, the welding current is 50-100A, the welding voltage is 15-22V, the wire feeding speed is 1-5m / min, and the powder feeding speed is 1-10g / min; the powder feeding argon gas flow rate is 5-8L / min, the ion gas flow rate of the ion gas supply system is 0.5-1L / min, and the shielding gas flow rate of the shielding gas system is 5-10L / min.

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