An apparatus and method for simultaneous cooling and hot filament in arc additive manufacturing.

Abstract

This invention discloses a device and method for simultaneous cooling and hot wire generation in arc additive manufacturing. The device includes: a vortex tube fixed to one side of a welding torch, with its inlet connected to an external compressed air source and its cold air outlet facing the additive component and fixed to the rear side of the welding torch corresponding to the additive direction; and a wire guide tube fixed obliquely to the outside of the welding torch, with a wire for additive manufacturing inserted inside the wire guide tube, the bottom end of the wire close to the working head of the welding torch. The inside of the wire guide tube is provided with a heating chamber for preheating the wire, the heating chamber being connected to the hot air outlet pipeline of the vortex tube, and an exhaust port on the wire guide tube corresponding to the heating chamber. This invention utilizes the vortex tube as a device for simultaneous generation of cold and hot air. The cold air is directionally blown towards the high-temperature deposited metal area adjacent to the arc movement of the working head, achieving high-efficiency and low-cost local high-temperature forced cooling. The hot air is delivered to the inside of the wire guide tube to preheat the wire, thereby improving deposition efficiency and reducing heat input.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, specifically relating to an apparatus and method for simultaneous cooling and hot wire in arc additive manufacturing. Background Technology

[0002] Arc additive manufacturing is a three-dimensional printing method based on metal arc melting technology. Its principle involves heating a metal material above its melting point using a high-current direct current discharge, then spraying or spinning it layer by layer under controlled conditions. The rapid melting and cooling of the metal creates continuous metal layers, ultimately constructing complex three-dimensional shapes. Arc additive manufacturing offers advantages such as high deposition efficiency and low cost, making it suitable for manufacturing large metal components. During the arc additive manufacturing process, forced cooling of the high-temperature deposited metal effectively controls its solidification behavior, resulting in refined microstructure and ideal properties. Furthermore, preheating the filament can improve deposition efficiency. Both forced cooling and hot filament techniques can reduce the heat input in additive manufacturing to some extent, reducing thermal stress and deformation, and mitigating the heat accumulation effect. This is particularly effective for alloys with a high tendency to crack (such as 7-series aluminum alloys and magnesium rare earth alloys), effectively improving forming quality and suppressing cracking.

[0003] Currently, online cooling technologies for deposited metals mainly include follow-up liquid nitrogen cooling, simultaneous gas cooling, and cooling of the forming chamber environment. Preheating methods for wire materials primarily include resistance heating, high-frequency induction heating, and electric arc heating. However, existing technologies have the following drawbacks:

[0004] Chinese patent CN201911388059.1 discloses a mechanism for a liquid nitrogen conduit and nozzle that move with the welding torch, enabling liquid nitrogen cooling of the deposited metal during additive manufacturing. However, the use of liquid nitrogen during additive manufacturing easily leads to water droplets adhering to the surface of the conduit and nozzle, which can drip onto the high-temperature deposited metal surface, causing oxidation and porosity defects. Furthermore, because the liquid nitrogen temperature is too low, excessive flow rate can significantly reduce arc heat, leading to incomplete fusion defects; conversely, insufficient flow rate makes effective forced cooling difficult. Therefore, using liquid nitrogen as a cooling medium is not conducive to practical temperature control.

[0005] Chinese patent CN 115229213 B discloses a cooling device for a molding chamber in additive manufacturing. However, this device requires the construction of a molding chamber environment, which limits its application in arc additive manufacturing of large-sized components. Furthermore, it primarily cools the entire molding chamber rather than specific high-temperature areas, resulting in lower cooling economy and efficiency.

[0006] The main methods for heating wire include resistance heating, induction heating, and arc heating. Resistance heating applies an electric current between the workpiece and the welding wire, using the heat generated by the resistance to heat the wire. Its advantages include rapid heating, precise temperature control, a small heat-affected zone, and applicability to various materials. However, the magnetic field generated during resistance heating can affect the stability of the arc; therefore, a constant AC voltage source is typically used for the hot wire power supply to reduce the influence of the magnetic field on the arc. Simultaneously, the open-circuit voltage of the hot wire heating power supply cannot be too high, otherwise the arc will ignite at the contact point between the hot wire and the workpiece, disrupting the stable hot wire heating process. Induction heating heats the welding wire by generating a current through electromagnetic induction. It can heat rapidly and has a relatively uniform temperature distribution. However, like resistance heating, the magnetic field generated during induction heating can also affect the stability of the arc. Arc heating for hot wire TIG welding offers advantages such as rapid heating, concentrated heat, and high weld quality, but also disadvantages such as high equipment requirements, operational difficulty, unstable wire feed speed, and high requirements for the surface condition of the base material. Furthermore, current technologies operate on the principle that cooling and heating filaments are independent of each other, lacking the technology to simultaneously cool high-temperature additive components and preheat filaments.

[0007] Therefore, how to provide a device and method that can simultaneously cool additive components and preheat filaments is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] In view of this, the present invention provides a device for simultaneous cooling and heating of the filament in electric arc additive manufacturing, which can simultaneously cool the additive component and preheat the filament, effectively improving the quality of additive manufacturing.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: a device for simultaneous cooling and hot wire in arc additive manufacturing, comprising:

[0010] A vortex tube is fixed to one side of the welding torch. The air inlet of the vortex tube is connected to an external compressed air source. The cold air outlet of the vortex tube faces the additive component and is fixed to the rear side of the welding torch corresponding to the additive direction.

[0011] A wire guide tube is fixed obliquely to the outside of the welding torch. A wire for additive manufacturing is inserted inside the wire guide tube. The bottom end of the wire is close to the working head of the welding torch. A heating chamber for preheating the wire is provided inside the wire guide tube. The heating chamber is connected to the hot gas outlet pipeline of the vortex tube. An exhaust port is provided on the wire guide tube corresponding to the heating chamber.

[0012] The beneficial effects of this invention are as follows: a compressed air source is introduced into the vortex tube, simultaneously generating cold and hot air. The cold air performs follow-up cooling on the high-temperature deposited metal, achieving high-efficiency and low-cost local high-temperature forced cooling temperature control, reducing the heat accumulation effect in the additive manufacturing process, and reducing residual stress and deformation. At the same time, the hot air enters the guide tube to preheat the filament, improving deposition efficiency, reducing heat input, and thus reducing residual stress and deformation. This invention simultaneously achieves the cooling of the high-temperature additive component and the preheating of the filament, with low equipment requirements and high forming quality.

[0013] Preferably, a bracket is fixed on the outer wall of the welding torch. The bracket is provided with a vortex tube clamp for fixing the vortex tube and a guide tube groove for fixing the guide tube. The bracket is provided with a sliding groove, and a telescopic support rod is slidably connected in the sliding groove. The telescopic end of the telescopic support rod is fixed with a clamping head for clamping the cold air outlet.

[0014] The resulting technical effect is that the position of the cold air outlet can be adjusted using the telescopic support rod to meet the cooling temperature requirements of different products.

[0015] Preferably, the guide wire tube includes two insertion sections and a heating section. The heating section is located between the two insertion sections. The inner side of the guide wire tube corresponding to the heating section is a heating cavity. One end of the heating section corresponding to the heating cavity is provided with a heat source inlet. A gas pipe is connected between the heat source inlet and the hot gas outlet of the vortex tube. The other end of the heating section corresponding to the heating cavity is provided with an exhaust port.

[0016] The resulting technical effect is that the tube section is used to clamp the wire, the heating section preheats the wire, the hot air source of the heating section is the hot air outlet of the vortex tube, and finally the gas in the heating chamber is discharged through the exhaust port.

[0017] Preferably, the end of the pipe section near the heat source inlet is provided with a conical guide surface. The conical guide surface is located inside the heating chamber. The hot air introduced through the heat source inlet enters the heating chamber under the action of the conical guide surface and is discharged through the exhaust port after preheating the wire.

[0018] The resulting technical effect is that the conical guide surface guides the hot gas flow, constrains the flow direction of the hot gas in the heating chamber, and reduces the impact of the hot gas on the arc of the welding torch working head.

[0019] Preferably, the outer diameter of the tube section is smaller than the inner diameter of the heating section.

[0020] Preferably, the external compressed air source is a high-purity compressed inert gas source and is stored in a high-pressure gas tank, and a high-pressure hose is connected between the jet port of the high-pressure gas tank and the air inlet of the vortex tube.

[0021] The resulting technical advantage is that it utilizes high-pressure gas tanks to provide the compressed gas required for the additive manufacturing process. It is also convenient to use.

[0022] The present invention also discloses a method for simultaneous cooling and hot filament in arc additive manufacturing, which includes the following steps:

[0023] Step 1: Assembly and debugging. Fix the vortex tube and guide wire tube to the outside of the welding torch. Connect the air inlet of the vortex tube to an external compressed air source. Adjust the distance between the cold air outlet of the vortex tube and the working head of the welding torch. Connect the heating chamber of the guide wire tube to the hot air outlet of the vortex tube. When installing the guide wire tube, keep the exhaust port away from the working head of the welding torch to avoid interference with the cold air outlet.

[0024] Step 2: Start additive welding. The welding torch is started. An external compressed air source is introduced into the vortex tube and generates cold and hot air. The inert gas used for cooling treatment performs follow-up cooling on the high-temperature deposited metal. At the same time, the hot air preheats the wire. The preheated wire improves the deposition efficiency, reduces heat input, and thus reduces residual stress and deformation.

[0025] Step 3: The welding torch is controlled by an external robotic arm and ultimately forms the additive component.

[0026] The beneficial effects of this invention are: by equipping the welding torch with an eddy current tube, cold air and hot air can be generated simultaneously. The cold air is used to cool the high-temperature deposited metal, and the targeted cooling effectively controls its solidification behavior, resulting in a refined microstructure and ideal properties. The hot air is used to preheat the wire, reducing energy input, reducing thermal stress and deformation, weakening the heat accumulation effect, and improving the forming quality of the product. Attached Figure Description

[0027] Figure 1 This is a structural diagram of a device for simultaneous cooling and hot wire in electric arc additive manufacturing according to the present invention;

[0028] Figure 2 This is a diagram showing the eddy current tube installation of a device for simultaneous cooling and hot wire in arc additive manufacturing according to the present invention.

[0029] Figure 3 This is a structural diagram of the wire guide tube of the device for synchronous cooling and hot wire in arc additive manufacturing according to the present invention;

[0030] Figure 4 This is a cross-sectional view of the wire guide tube of the device for synchronous cooling and hot wire in electric arc additive manufacturing according to the present invention.

[0031] 1. Vortex tube, 11. Air inlet, 12. Hot air outlet, 13. Cold air outlet, 14. Gas pipe, 2. Welding torch, 21. Working head, 3. Support, 31. Slide groove, 4. Telescopic support rod, 5. Guide wire tube, 51. Pipe section, 52. Heating section, 53. Heating chamber, 54. Conical guide surface, 55. Exhaust port, 6. Wire, 7. Additive component, 8. High-pressure gas tank. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] See the appendix of this invention. Figures 1 to 4 According to an embodiment of the present invention, an apparatus for simultaneous cooling and hot filament in arc additive manufacturing includes:

[0034] Vortex tube 1 is fixed on one side of welding torch 2. The air inlet 11 of vortex tube 1 is connected to an external compressed air source. The cold air outlet 13 of vortex tube 1 faces the additive component 7 and is fixed on the rear side of welding torch 2 corresponding to the additive direction.

[0035] The wire guide tube 5 is fixed at an angle to the outside of the welding torch 2. The wire guide tube 5 contains a wire 6 for additive manufacturing. The bottom end of the wire 6 is close to the working head 21 of the welding torch. The working head generates an electric arc. The inside of the wire guide tube 5 is provided with a heating chamber 53 for preheating the wire. The heating chamber 53 is connected to the hot gas outlet 12 of the vortex tube 1. The wire guide tube 5 is provided with an exhaust port 55 corresponding to the heating chamber. The wire preheated by the hot gas can improve the deposition efficiency, reduce heat input, and thus reduce residual stress and deformation.

[0036] In other embodiments, a bracket 3 is fixed on the outer wall of the welding torch 2. The bracket 3 is provided with a vortex tube clamp for fixing the vortex tube 1 and a guide tube groove for fixing the guide tube 5. The bracket 3 is provided with a sliding groove 31, and a telescopic support rod 4 is slidably connected in the sliding groove 31. The telescopic end of the telescopic support rod 4 is fixed with a clamping head for clamping the cold air outlet 13. The distance between the cold air outlet and the welding torch can be adjusted by the cooperation between the sliding groove and the telescopic support rod. Different distances are set according to different materials.

[0037] In some other specific embodiments, the guide tube 5 includes two tube sections 51 and a heating section 52. The heating section 52 is located between the two tube sections 51. The inner side of the guide tube 5 corresponding to the heating section is a heating cavity 53. One end of the heating section 52 corresponding to the heating cavity is provided with a heat source inlet. A gas pipe 14 is connected between the heat source inlet and the hot gas outlet of the vortex tube. The other end of the heating section 52 corresponding to the heating cavity 53 is provided with an exhaust port 55. The hot gas is used to preheat the wire.

[0038] In some other embodiments, a tapered guide surface 54 is provided at the end of the tube section 51 near the heat source inlet. The tapered guide surface 54 is located inside the heating chamber 53. The hot air introduced through the heat source inlet enters the heating chamber under the action of the tapered guide surface 54, preheats the wire, and then exits through the exhaust port. The tapered guide surface can constrain the flow direction of the hot gas, preventing the hot gas from flowing out of the wire outlet of the guide tube and thus affecting the electric arc.

[0039] In some other specific embodiments, the outer diameter of the tube section 51 is smaller than the inner diameter of the heating section 52. The size of the heating tube directly affects the size of the heating cavity and must meet the preheating time requirements of the hot gas on the wire.

[0040] In other embodiments, the external compressed gas source is a high-purity compressed inert gas source and is stored in a high-pressure gas tank 8. A high-pressure hose is connected between the jet port of the high-pressure gas tank 8 and the air inlet of the vortex tube 1. In this embodiment, high-purity compressed argon is used.

[0041] The present invention also discloses a method for simultaneous cooling and hot filament in arc additive manufacturing, which includes the following steps:

[0042] Step 1: Assembly and debugging. Fix the vortex tube and guide wire tube to the outside of the welding torch. Connect the air inlet of the vortex tube to an external compressed air source. Adjust the distance between the cold air outlet of the vortex tube and the working head of the welding torch. Connect the heating chamber of the guide wire tube to the hot air outlet of the vortex tube. When installing the guide wire tube, keep the exhaust port away from the working head of the welding torch to avoid interference with the cold air outlet.

[0043] Step 2: Start additive welding. The welding torch is started. An external compressed air source is introduced into the vortex tube and generates cold and hot air. The inert gas used for cooling treatment performs follow-up cooling on the high-temperature deposited metal. At the same time, the hot air preheats the wire. The preheated wire improves the deposition efficiency, reduces heat input, and thus reduces residual stress and deformation.

[0044] Step 3: The welding torch is controlled by an external robotic arm and ultimately forms the additive component.

[0045] This invention employs a vortex tube mounted on a welding torch as a device for the simultaneous generation of cold and hot air. The working principle of the vortex tube is as follows: compressed and cooled gas enters the nozzle, expands and accelerates to the speed of sound within the nozzle, and is injected tangentially into the vortex chamber, forming a free vortex. The rotational angular velocity of the free vortex increases closer to the center. Due to the difference in angular velocity, friction is generated between the layers of the free vortex. The airflow in the central part has the highest angular velocity, and the friction results in the transfer of energy to the outer layer of airflow with a lower angular velocity. The airflow in the central layer loses energy, its kinetic energy decreases, its speed decreases, and its temperature decreases. It is then drawn out from one end through the orifice plate in the center of the vortex tube, obtaining the cold airflow required for cooling. Meanwhile, the airflow in the outer layer gains momentum, its kinetic energy increases, and it also rubs against the turbine tube wall, converting some of its kinetic energy into heat energy. This heat energy is then drawn out from the other end of the vortex tube through a control valve, forming a hot airflow. The flow rate and temperature of the cold and hot airflows can be adjusted by controlling the control valve.

[0046] In the additive manufacturing process, inert gas cooled by vortex tubes provides dynamic cooling to the high-temperature deposited metal, achieving efficient and low-cost localized high-temperature forced cooling temperature control. This reduces the heat accumulation effect during the additive manufacturing process, minimizing residual stress and deformation. Simultaneously, the inert heat generated by the vortex tubes is used to preheat the filament, improving deposition efficiency, reducing heat input, and further decreasing residual stress and deformation. This invention offers the following advantages:

[0047] The inert cooling air is directed towards the high-temperature deposited metal area near the rear of the electric arc, achieving high-efficiency and low-cost local high-temperature forced cooling and temperature control.

[0048] Using inert hot gas as the heating medium, the problem of magnetic field affecting the stability of electric arc is avoided during the resistance heating and induction heating processes, while effectively preheating the wire.

[0049] The apparatus and methods disclosed in the embodiments are described simply because they correspond to the methods disclosed in the embodiments. For relevant details, please refer to the method section.

[0050] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for simultaneous cooling and hot filament in arc additive manufacturing, characterized in that, include: Vortex tube (1), the vortex tube (1) is fixed on one side of the welding torch (2), the air inlet (11) of the vortex tube (1) is connected to an external compressed air source, and the cold air outlet (13) of the vortex tube (1) faces the additive component (7) and is fixed on the rear side of the welding torch (2) in the additive direction. The wire guide tube (5) is obliquely fixed to the outside of the welding torch (2). The wire guide tube (5) is filled with a wire (6) for additive manufacturing. The bottom end of the wire (6) is close to the working head (21) of the welding torch. The inside of the wire guide tube (5) is provided with a heating chamber (53) for preheating the wire. The heating chamber (53) is connected to the hot gas outlet (12) of the vortex tube (1). The wire guide tube (5) is provided with an exhaust port (55) corresponding to the heating chamber.

2. The apparatus for simultaneous cooling and hot filament in arc additive manufacturing according to claim 1, characterized in that, A bracket (3) is fixed on the outer wall of the welding torch (2). The bracket (3) is provided with a vortex tube clamp for fixing the vortex tube (1) and a guide tube groove for fixing the guide tube (5). The bracket (3) is provided with a sliding groove (31). A telescopic support rod (4) is slidably connected in the sliding groove (31). The telescopic end of the telescopic support rod (4) is fixed with a clamping head for clamping the cold air outlet (13).

3. The apparatus for simultaneous cooling and hot filament in arc additive manufacturing according to claim 1, characterized in that, The guide wire tube (5) includes two insertion sections (51) and a heating section (52). The heating section (52) is located between the two insertion sections (51). The inner side of the guide wire tube (5) corresponding to the heating section is a heating chamber (53). One end of the heating section (52) corresponding to the heating chamber is provided with a heat source inlet. A gas pipe (14) is connected between the heat source inlet and the hot gas outlet of the vortex tube. The other end of the heating section (52) corresponding to the heating chamber (53) is provided with an exhaust port (55).

4. The apparatus for simultaneous cooling and hot filament in arc additive manufacturing according to claim 3, characterized in that, The tube section (51) is provided with a conical guide surface (54) at one end near the heat source inlet. The conical guide surface (54) is located inside the heating chamber (53). The hot air introduced through the heat source inlet enters the heating chamber under the action of the conical guide surface (54) and preheats the wire before being discharged through the exhaust port.

5. The apparatus for simultaneous cooling and hot filament in arc additive manufacturing according to claim 4, characterized in that, The outer diameter of the tube section (51) is smaller than the inner diameter of the heating section (52).

6. The apparatus for simultaneous cooling and hot filament in arc additive manufacturing according to any one of claims 1-5, characterized in that, The external compressed air source is a high-purity compressed inert gas source and is stored in a high-pressure gas tank (8). A high-pressure hose is connected between the jet port of the high-pressure gas tank (8) and the air inlet of the vortex tube (1).

7. A method using the apparatus for simultaneous cooling and hot filament in arc additive manufacturing as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Assembly and debugging. Fix the vortex tube and guide wire tube to the outside of the welding torch. Connect the air inlet of the vortex tube to an external compressed air source. Adjust the distance between the cold air outlet of the vortex tube and the working head of the welding torch. Connect the heating chamber of the guide wire tube to the hot air outlet of the vortex tube. When installing the guide wire tube, keep the exhaust port away from the working head of the welding torch to avoid interference with the cold air outlet. Step 2: Start additive welding. The welding torch is started. An external compressed air source is introduced into the vortex tube and generates cold and hot air. The inert gas used for cooling treatment performs follow-up cooling on the high-temperature deposited metal. At the same time, the hot air preheats the wire. The preheated wire improves the deposition efficiency, reduces heat input, and thus reduces residual stress and deformation. Step 3: The welding torch is controlled by an external robotic arm and ultimately forms the additive component.

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