Multi-field assisted metal fuse additive melt directional transfer device and method

Abstract

The present invention provides a multi-field assisted metal fused wire additive melt directional transfer device and method. The device includes a laser energy source system, a metal wire feeding system, a constant magnetic field system, an electric field system, a coaxial shielding gas system, an ultrasonic generator, a multi-axis motion platform, and a forming base. The forming base is fixedly mounted above the multi-axis motion platform, which enables the forming base to move in multiple degrees of freedom in space. The laser energy source system is fixed above the forming base, so that the laser emitted by the laser energy source system irradiates the upper surface of the forming base. The metal wire feeding system is fixed to the side of the laser energy source system and transports the metal wire within the size range of the laser spot. The constant magnetic field system, electric field system, and ultrasonic generator are respectively fixed to the metal wire feeding system. The multi-axis motion platform has four degrees of freedom: X, Y, and Z axes of motion and platform rotation. The present invention achieves the application of a specific field at the end of the metal wire by allocating the installation position of the auxiliary field.

Description

Technical Field

[0001] The present invention relates to the field of laser additive manufacturing in a space microgravity environment, and in particular to a multi-field assisted metal fuse additive melt directional transfer device and method. Background Art

[0002] Space exploration, space resource development and other fields are currently the main areas of competition among countries. Therefore, it is urgent to develop technologies and equipment for metal additive manufacturing in a microgravity environment in space, so as to provide in-situ manufacturing methods and means for parts for space projects such as space stations and space bases, and reduce the dependence of space exploration needs on ground supplies. This has important prospects and application value. When the microgravity level in space reaches 10 -2 g~10 -5 g. The movement of matter is not constrained by gravity, and the flow behavior of fluids is very different from that of the ground environment.

[0003] Laser metal fuse additive manufacturing under microgravity is one of the most effective methods of in-situ manufacturing in space. During the manufacturing process, a portion of the laser energy is used to melt the metal wire, which absorbs the laser energy to form a liquid melt at the end. In addition, the laser energy acts on the forming substrate to form a liquid metal molten pool. Whether the melt at the end of the wire can enter the substrate molten pool is a key issue that determines the effectiveness of metal fuse additive manufacturing technology in space microgravity. However, the liquid melt formed at the end of the metal wire is not constrained by gravity in the space environment. The surface tension of the melt and the viscosity of the fluid become the main factors affecting the flow behavior of the melt. The metal melt is prone to problems such as balling and creeping back along the wire, making it impossible to smoothly and directional enter the molten pool. More seriously, the metal melt at the end of the wire creeping back along the wire can cause the wire feeding mechanism of the additive manufacturing equipment to become blocked, resulting in more serious consequences. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a multi-field assisted metal fuse additive melt directional transfer device and method, which applies auxiliary fields, such as electric fields, magnetic fields and ultrasonic vibrations, and allocates the installation positions of the auxiliary fields to achieve the application of specific fields at the end of the metal wire.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A multi-field assisted metal fuse additive melt directional transfer device includes a laser energy source system, a metal wire feeding system, a constant magnetic field system, an electric field system, a coaxial shielding gas system, an ultrasonic generator, a multi-axis motion platform and a forming substrate; the forming substrate is fixedly installed above the multi-axis motion platform, and the multi-axis motion platform realizes the multi-degree-of-freedom movement of the forming substrate in space; the laser energy source system is fixed above the forming substrate so that the laser emitted by the laser energy source system irradiates the upper surface of the forming substrate; the metal wire feeding system is fixed on the side of the laser energy source system to transport the metal wire within the size range of the laser spot; the constant magnetic field system, the electric field system and the ultrasonic generator are respectively fixed on the metal wire feeding system; the multi-axis motion platform includes four degrees of freedom: X, Y, Z axis movement and platform rotation.

[0007] Furthermore, the laser energy source system includes multiple laser beams, which are generated by multiple laser light sources or a laser beam generated by a spectroscope system; the spatial relationship between the laser irradiation position and the metal wire and the forming substrate is adjusted by a position adjustment mechanism.

[0008] Furthermore, the metal wire feeding system includes a metal wire, a metal wire angle adjustment bracket, an insulating sleeve, a wire coaxial air blowing pipe and a wire feeder; the insulating sleeve and the wire coaxial air blowing pipe are coaxially arranged and installed on the metal wire angle adjustment bracket with the metal wire, and the metal wire angle adjustment bracket is used to adjust the angle between the direction of the metal wire fed into the molten pool and the horizontal direction, and ensure that the wire coaxial air blowing pipe is always coaxial with the metal wire; the wire feeder is fixed on the metal wire angle adjustment bracket and is located at the metal wire inlet end of the wire coaxial air blowing pipe, and the position of the wire feeder is synchronously adjusted while adjusting the angle between the direction of the metal wire fed into the molten pool and the horizontal direction.

[0009] Furthermore, the constant magnetic field system includes a permanent magnet, a magnet holder and a magnetic field meter; the magnet holder is used to fix the permanent magnet to the wire coaxial blowing pipe; there are two permanent magnets, which are symmetrically arranged on both sides of the end of the metal wire to generate a constant magnetic field, and the direction of the magnetic field generated by the permanent magnet is perpendicular to the axial direction of the metal wire; the magnetic field meter is located between the permanent magnet and the metal wire, and is used to measure the magnetic field strength at the end of the metal wire where the melt is formed.

[0010] Furthermore, the electric field system includes a DC power supply and a current clamp; there are two current clamps, which are fixed on the metal wire and the forming substrate respectively, and a stable current is formed between the metal wire and the forming substrate using the DC power supply.

[0011] Furthermore, the coaxial protective gas system includes a laser coaxial air blowing pipe, a transparent lens, protective gas, a first flow meter and a second flow meter; two paths of protective gas are designed, the first path is: the laser coaxial air blowing pipe is arranged directly below the first continuous laser source among multiple laser light sources, ensuring that the laser light of the first continuous laser source can be vertically and coaxially irradiated onto the forming substrate through the transparent lens; the second path is: the protective gas is ejected through the second flow meter and the wire coaxial air blowing pipe, and the protective gas of the second path is coaxially ejected with the metal wire; the protective gas is an inert gas, and the flow rate of the protective gas entering the laser coaxial air blowing pipe is accurately adjusted by the first flow meter, and the flow rate of the protective gas entering the wire coaxial air blowing pipe is accurately adjusted by the second flow meter.

[0012] Furthermore, there are n types of metal wires, where n is a positive integer greater than or equal to 1; the metal wires are evenly arranged within a 360-degree geometric range according to the number of types; the metal wires are installed on an angle adjustment mechanism, and the angle adjustment mechanism can be used to adjust the angle between the metal wires and the horizontal plane; the types of metal wires are materials of the same type or different types, including stainless steel wires, aluminum alloy wires, titanium alloy wires, flux-cored welding wires, high / medium entropy alloys, amorphous alloy wires, and composite material wires.

[0013] Furthermore, an ultrasonic generator is installed at a certain distance away from the end of the metal wire, and the ultrasonic vibration stirs the end melt, thereby promoting the directional transfer of the end melt from the metal wire to the forming substrate.

[0014] The present invention also provides a multi-field assisted metal fuse additive melt directional transfer method, which is implemented using the multi-field assisted metal fuse additive melt directional transfer device described above, and includes the following steps:

[0015] Step S1, adjusting the relative positions of the first continuous laser source and the first pulsed laser source of the laser energy source system and the metal wire and the initial processing position of the forming substrate;

[0016] Step S2: Slice the data according to the three-dimensional model to be constructed, and ensure that the wire feeding direction of the metal wire is always parallel to the forming direction and kept at the front end of the forming direction through the rotational freedom of the multi-axis motion platform;

[0017] Step S3: sequentially starting the shielding gas, the first continuous laser source, the first pulsed laser source, the DC power supply, and the wire feeder. After the first metal wire contacts the forming substrate, a current loop is generated between the first metal wire and the forming substrate. The current loop is used as a control signal to start additive manufacturing according to the slice trajectory data of the three-dimensional model.

[0018] Step S4: After processing according to the slice trajectory data in the current forming layer, the wire feeder, DC power supply, laser source and shielding gas are turned off in sequence, and the forming substrate is moved to the initial position of the next trajectory by the multi-axis motion platform;

[0019] Step S5: Repeat steps S1, S2, S3 and S4 until the entire three-dimensional component is processed.

[0020] Furthermore, the flow rate of the shielding gas is 0L / min~50L / min; the laser source is used to output pulsed laser or continuous laser, its maximum output power is 4000W, the pulse frequency is 10Hz~1000HZ, the laser pulse width is 2~50ms, and its scanning speed is 50mm / min~2000mm / min; the maximum output current of the DC power supply is 400A; the wire feeder is used to achieve metal wire feeding with a wire diameter of 0.1mm~10mm.

[0021] Beneficial effects:

[0022] 1. The present invention proposes to use a constant magnetic field and an electrostatic field to generate a directional Lorentz force on the melt at the end of the metal wire, thereby promoting the directional transfer of the melt formed at the end of the metal wire to the molten pool.

[0023] 2. In the present invention, the constant magnetic field generates electromagnetic stirring on the metal molten pool, making the solidified structure of the material uniform and refined, thereby improving the performance of the formed part.

[0024] 3. The present invention proposes a solution of using multiple laser beams. The molten pool generated by the multiple laser beams and the metal matrix reduces the temperature gradient of the molten pool, thereby reducing the surface tension and promoting the wetting and spreading of the molten metal.

[0025] 4. The present invention uses ultrasonic vibration at the end of the metal wire to increase the disturbance of the melt at the end of the metal wire, promote the separation of the melt from the end of the metal wire, and prevent the melt from creeping back along the wire.

[0026] 5. The present invention adopts multi-layer inert gas shielding jets, and utilizes the gas pressure formed by the jet acting on the melt at the metal end and the gas-liquid interface of the molten pool to promote the directional transport of the molten metal to the molten pool, avoiding the molten metal from creeping back along the wire under the condition of no gravity constraint, thereby stabilizing the molten pool and preventing the wire feeding mechanism from being blocked by the creeping back of liquid droplets. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the multi-field assisted metal fuse additive melt directional transfer device of the present invention;

[0028] Figure 2 Schematic diagram of two laser distribution structures of a single metal wire;

[0029] Figure 3 Schematic diagram of the multi-continuous laser distribution structure of a single metal wire;

[0030] Figure 4 A top-down diagram of the multi-laser distribution and the positions of various metal wires;

[0031] Figure 5 It is the force analysis principle diagram of the present invention.

[0032] Among them, the accompanying drawings are marked as: end melt 1, laser energy source system 111, metal wire feeding system 211, constant magnetic field system 311, electric field system 411, coaxial shielding gas system 511, ultrasonic generator 6111, multi-axis motion platform 7111, forming substrate 7112, first continuous laser source 1111, second continuous laser source 1121, third continuous laser source 1131, fourth continuous laser source 1141, position adjustment mechanism 1113, metal wire angle adjustment bracket 2112, insulating sleeve 2113, wire coaxial blowing pipe 2114, wire feeding machine 21 15. Permanent magnet 3111, magnet holder 3112, magnetic field measuring instrument 3113, magnetic field 3114, DC power supply 4111, current clamp 4112, laser coaxial air blowing tube 5111, light-transmitting lens 5112, shielding gas 5113, first flowmeter 5114, second flowmeter 5115, first pulsed laser source 1112, second pulsed laser source 1122, third pulsed laser source 1132, fourth pulsed laser source 1142, first metal wire 2111, second metal wire 2121, third metal wire 2131, fourth metal wire 2141. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0034] like Figure 1As shown, the multi-field assisted metal fuse additive melt directional transfer device of the present invention includes a laser energy source system 111, a metal wire feeding system 211, a constant magnetic field system 311, an electric field system 411, a coaxial shielding gas system 511, an ultrasonic generator 6111, a multi-axis motion platform 7111 and a forming substrate 7112. Among them, the forming substrate 7112 is fixedly installed above the multi-axis motion platform 7111, and the multi-axis motion platform 7111 can realize the movement of the forming substrate 7112 in multiple degrees of freedom in space; the laser energy source system 111 is fixed above the forming substrate 7112, so that the laser emitted by the laser energy source system 111 can irradiate the upper surface of the forming substrate 7112; the metal wire feeding system 211 is fixed on the side of the laser energy source system 111, and can realize the transportation of the metal wire to the size range of the laser spot; the constant magnetic field system 311, the electric field system 411 and the ultrasonic generator 6111 are respectively fixed on the metal wire feeding system 211. The auxiliary field applied in the present invention includes electric field, magnetic field and ultrasonic vibration, and a specific field is applied to the end of the metal wire through the installation position of the auxiliary field.

[0035] The laser energy source system 111 includes a single or multiple laser beams. Multiple laser beams can be generated by multiple laser sources or a single laser beam through a spectroscopic system. The multiple laser beams include various energy combinations of continuous laser and pulsed laser.

[0036] Preferably, when the multiple laser beams are composed of continuous laser and pulsed laser, the laser energy source system 111 may include a first continuous laser 1111 and a first pulsed laser source 1112. The spatial relationship between the laser irradiation position and the first metal wire 2111 and the forming substrate 7112 may be adjusted by a position adjustment mechanism 1113. The first continuous laser source 1111 irradiates the forming substrate 7112 through the laser coaxial blowing tube 5111 to form a stable molten pool on the forming substrate 7112. The laser of the first pulsed laser source 1112 irradiates the end of the first metal wire 2111. The functions of the first pulsed laser source 1112 are: (1) melting the end of the first metal wire 2111 to form an end melt 1; and (2) forming a recoil pressure on the surface of the end melt 1 to promote the transfer of the end melt 1 to the molten pool on the forming substrate 7112.

[0037] The wire feeding system 211 includes a first metal wire 2111, a wire angle adjustment bracket 2112, an insulating sleeve 2113, a wire coaxial air blowing pipe 2114, and a wire feeder 2115. The insulating sleeve 2113 and the wire coaxial air blowing pipe 2114 are coaxially arranged and mounted on the wire angle adjustment bracket 2112 with the first metal wire 2111. The wire angle adjustment bracket 2112 is used to adjust the angle between the direction in which the wire is fed into the molten pool and the horizontal direction, and to ensure that the wire coaxial air blowing pipe 2114 remains coaxial with the first metal wire 2111. The wire feeder 2115 is fixed to the wire angle adjustment bracket 2112 and is located at the wire inlet end of the wire coaxial air blowing pipe 2114. The position of the wire feeder 2115 can be adjusted simultaneously with the horizontal angle between the direction in which the first metal wire 2111 is fed into the molten pool.

[0038] The constant magnetic field system 311 includes a permanent magnet 3111, a magnet holder 3112, and a magnetic field meter 3113. The magnet holder 3112 is used to securely connect the permanent magnet 3111 to the wire coaxial blowpipe 2114. Two permanent magnets 3111 are symmetrically arranged on either side of the end of the first metal wire 2111, generating a constant magnetic field. The direction of the magnetic field 3114 generated by the permanent magnets 3111 is perpendicular to the axial direction of the first metal wire 2111. The magnetic field meter 3113 is located between the permanent magnet 3111 and the first metal wire 2111 and is used to measure the magnetic field strength at the end of the first metal wire 2111 where the melt is formed.

[0039] The electric field system 411 includes a DC power supply 4111 and current clamps 4112. Two current clamps 4112 are fixed to the first metal wire 2111 and the forming substrate 7112, respectively. The present invention utilizes the DC power supply 4111 to generate a stable current between the first metal wire 2111 and the forming substrate 7112.

[0040] The coaxial shielding gas system 511 includes a laser coaxial blowpipe 5111, a light-transmitting lens 5112, shielding gas 5113, a first flowmeter 5114, and a second flowmeter 5115. The present invention employs a two-way shielding gas system. The first route is: the laser coaxial blowpipe 5111 is positioned directly below the first continuous laser source 1111, ensuring that the laser beam from the first continuous laser source 1111 can be vertically and coaxially irradiated onto the forming substrate 7112 through the light-transmitting lens 5112. The shielding gas 5113 is an inert gas, and the flow rate of the shielding gas 5113 entering the laser coaxial blowpipe 5111 can be precisely adjusted by the first flowmeter 5114. The second route is: the shielding gas 5113 is ejected through the second flowmeter 5115 and the wire coaxial blowpipe 2114. The shielding gas 5113 in the second route can be ejected coaxially with the first metal wire 2111. The first flow meter 5114 is installed on the air flow path between the laser coaxial blowing pipe 5111 and the shielding gas 5113 ; the second flow meter 5115 is installed on the air flow path between the wire coaxial blowing pipe 2114 and the shielding gas 5113 .

[0041] In the present invention, an ultrasonic generator 6111 is installed at a certain distance away from the end of the first metal wire 2111. The ultrasonic vibration stirs the end melt 1, promoting the directional transfer of the end melt 1 from the metal wire to the forming substrate 7112.

[0042] Preferably, the number of types of the first metal wire 2111 can be n. The metal wires are evenly arranged within a 360-degree geometric range according to the number of types. The metal wire angle adjustment bracket 2112 is used to adjust the angle between the first metal wire 2111 and the horizontal plane. The types of the metal wires can be the same type of material and different types of materials, including but not limited to stainless steel wire, aluminum alloy wire, titanium alloy wire, flux-cored welding wire, high / medium entropy alloy, amorphous alloy wire and composite material wire. The multi-axis motion platform 7111 includes four degrees of freedom: X, Y, Z axis motion and platform rotation. The multi-axis motion platform 7111 is used to support the forming substrate 7112 to achieve multi-axis motion control of the forming substrate 7112.

[0043] The working principle of the present invention includes:

[0044] 1. Principle of Ultrasonic Vibration Assistance: In the present invention, an ultrasonic generator is installed at a distance from the end of the first metal wire 2111. Ultrasonic vibration stirs the melt 1 at the end, promoting its directional transfer from the metal wire to the forming substrate 7112. Ultrasonic vibration can also break up solidified crystals, induce recrystallization, refine grains, and improve the microstructure and mechanical properties of the formed component.

[0045] 2. Principle of Stable Magnetic Field Assistance: Based on the Lorentz force exerted on moving charges in a magnetic field, the present invention applies a constant magnetic field within the horizontal plane of the first metal wire 2111. Simultaneously, a constant current is applied between the first metal wire 2111 and the forming substrate 7112. By matching the directions of the current and the constant magnetic field according to the Lorentz left-hand rule, electrons in the melt generate a Lorentz force (in the Z+ direction) directed toward the forming substrate 7112. This Lorentz force promotes the transfer of the molten metal into the substrate melt pool.

[0046] 3. Analysis of the force on the end melt: The force on the end melt 1 of the first metal wire 2111 is as follows: Figure 5 As shown in the figure, the forces acting on the end melt 1 primarily include surface tension Fs, the pressure Fw of the coaxial blowing of the metal wire, the recoil force Fr generated by metal evaporation, the pressure Fg of the coaxial blowing of the laser, the viscous force Fd between the metal end melt 1 and the substrate molten pool, the Lorentz force Fb, and the thrust Ft of the metal wire on the end melt. The surface tension Fs generates a Z-direction force component Fs_Z. The pressure Fw of the coaxial blowing of the metal wire generated by the structure of the present invention on the end melt 1, the recoil force Fr generated by metal evaporation, the pressure Fg of the coaxial blowing of the laser, and the Lorentz force Fb all contribute to the directional transfer of the melt toward the substrate molten pool. When the gas pressure Fw of the coaxial blowing of the metal wire, the recoil force Fr generated by metal evaporation, the gas pressure Fg of the coaxial blowing of the laser, the viscous force Fd between the metal end melt 1 and the substrate molten pool, the Lorentz force Fb, and the thrust Ft of the metal wire on the end melt in the Z direction are greater than the component of the surface tension Fs in the Z direction, that is: Fw_Z + Fr_Z + Fg_Z + Fd_Z + Fb_Z + Ft_Z >Fs_Z, the end melt 1 can be smoothly transported into the molten pool.

[0047] In the present invention, the gas pressure generated by the coaxial airflow, the recoil force generated by metal evaporation and the Lorentz force generated by the electromagnetic field are all conducive to separating the metal end melt from the metal wire and transporting them in a directionally transported manner into the molten pool of the forming substrate.

[0048] The present invention also provides a multi-field assisted metal fuse additive melt directional transfer method, which is implemented using the multi-field assisted metal fuse additive melt directional transfer device described above. The method comprises the following steps:

[0049] Step S1, manufacturing preparation: adjusting the relative positions of the first continuous laser source 1111 and the first pulsed laser source 1112 and the first metal wire 2111 and the initial processing position of the forming substrate 7112;

[0050] Step S2, data preparation: data slicing is performed according to the three-dimensional model to be constructed, and the rotational freedom of the multi-axis motion platform 7111 is used to ensure that the feeding direction of the first metal wire 2111 is always parallel to the forming direction and is kept at the front end of the forming direction;

[0051] Step S3, starting processing: The shielding gas 5113, the first continuous laser source 1111, the first pulsed laser source 1112, the DC power supply 4111, and the wire feeder 2115 are sequentially started. After the first metal wire 2111 contacts the forming substrate 7112, a current loop is generated between the first metal wire 2111 and the forming substrate 7112. The current is used as a control signal to start additive processing according to the slice trajectory data of the three-dimensional model.

[0052] Step S4, processing end: After processing according to the slice trajectory data in the current forming layer, the wire feeder 2115, DC power supply 4111, laser source and shielding gas 5113 are turned off in sequence, and the forming substrate 7112 is moved to the initial position of the next trajectory by the multi-axis motion platform 7111;

[0053] Step S5: Repeat steps S1, S2, S3 and S4 until the entire three-dimensional component is processed.

[0054] Preferably, the flow rate of the protective gas 5113 is 0L / min~50L / min; the laser source is used to output pulsed laser or continuous laser, its maximum output power is 4000W, the pulse frequency is 10Hz~1000HZ, the laser pulse width is 2~50ms, and its scanning speed is 50mm / min~2000mm / min; the maximum output current of the DC power supply 4111 is 400A; the wire feeder 2115 is used to achieve metal wire feeding with a wire diameter of 0.1mm~10mm.

[0055] Example 1:

[0056] As Figure 2The two laser beams shown are used as an example for illustration. In this embodiment, the number of metal wires n = 1. The laser energy source system 111 includes a first continuous laser source 1111 and a first pulsed laser source 1112. The laser beam from the first continuous laser source 1111 acts on the forming substrate 7112, and the end of the metal wire is not within the range of the beam spot of the first continuous laser source 1111. The beam spot of the first pulsed laser source 1112 directly illuminates the end of the metal wire. The first pulsed laser source 1112 directly melts the metal wire. The instantaneous high energy of the pulsed laser interacts with the metal wire to generate recoil steam pressure, which facilitates the separation of the end melt from the metal wire and its directionally transported into the substrate molten pool. The protective gas flows in the wire coaxial air blowing tube 2114 and the laser coaxial air blowing tube 5111 are set respectively, and the flow rate of the protective gas is 10L / min~50L / min; the parameters of the first pulsed laser source 1112 are set, and the maximum output power of the pulsed laser is 200W~4000W, the pulse frequency is 10Hz~1000HZ, and the laser pulse width is 2~50ms; the parameters of the first continuous laser source 1111 are set, and the continuous laser power is 200W~1000W.

[0057] Example 2:

[0058] As Figure 3 The illustrated multiple continuous laser beams are used as an example. In this embodiment, the number of metal wire materials, n, is 1, and the number of multiple continuous laser beams is 4. The laser energy source system 111 includes multiple continuous laser beams, namely a first continuous laser source 1111, a second continuous laser source 1121, a third continuous laser source 1131, and a fourth continuous laser source 1141. These multiple laser beams are evenly distributed over a 360-degree circumference, forming a circular laser energy distribution in space. The multiple laser beams act on a forming substrate 7112. A position adjustment mechanism 1113 is used to insert the end of the metal wire into the geometric center of the multiple laser beams and bring them into contact with the forming substrate 7112. Because the laser beams act simultaneously on the end of the metal wire and the forming substrate 7112, the metal wire is melted while a molten pool forms on the forming substrate. The circular distribution of the multiple laser beams makes the temperature field of the molten pool formed on the forming substrate more uniform, and the laser light pressure further promotes the transfer of the metal wire melt into the molten pool on the forming substrate 7112. At the same time, protective gas flows are set in the wire coaxial blowing pipe 2114 and the laser coaxial blowing pipe 5111 respectively, and the flow rate of the protective gas is 10L / min~50L / min; the protective gas is used to prevent the molten pool from being oxidized and to generate gas pressure to promote melt transfer, and the laser power is 200W~1000W.

[0059] Example 3:

[0060] As Figure 4For illustration, in this embodiment, the number of metal wire materials n=4, and the number of laser beams is set to five, including a first pulsed laser source 1112, a second pulsed laser source 1122, a third pulsed laser source 1132, and a fourth pulsed laser source 1142. The four pulsed laser beams respectively irradiate the ends of the first metal wire 2111, the second metal wire 2121, the third metal wire 2131, and the fourth metal wire 2141. The laser beam from the first continuous laser source 1111 is irradiated at the center of the four pulsed laser beams. The first continuous laser source 1111 is used to form a stable molten pool on the forming substrate 7112. The present invention can achieve directional transfer of the melt at the ends of the metal wires using only the gas pressure generated by the coaxial airflow and the recoil force generated by metal evaporation. The shielding gas flow in the wire coaxial air blowing pipe 2114 and the laser coaxial air blowing pipe 5111 is set to a flow rate of 10 L / min to 50 L / min. The parameters of the first pulsed laser source 1112, the second pulsed laser source 1122, the third pulsed laser source 1132, and the fourth pulsed laser source 1142 are set to a maximum output power of 200 W to 4000 W, a pulse frequency of 10 Hz to 1000 Hz, and a laser pulse width of 2 to 50 ms. The parameters of the first continuous laser source 1111 are set to a continuous laser power of 200 W to 1000 W. In this embodiment, the order in which the four metal wires are added can be controlled by a control system, thereby achieving metal fused wire additive manufacturing of a gradient structure.

[0061] Example 4:

[0062] The present invention can achieve directional transfer of melt at the end of a metal wire using only the Lorentz force generated by an electromagnetic field and the recoil force generated by metal evaporation. The parameters of a first pulsed laser source 1112, a second pulsed laser source 1122, a third pulsed laser source 1132, and a fourth pulsed laser source 1142 are set, respectively, with the maximum output power of the pulsed lasers ranging from 200W to 4000W, the pulse frequency ranging from 10Hz to 1000Hz, and the laser pulse width ranging from 2 to 50ms. The parameters of a first continuous laser 1111 are set, with the continuous laser power ranging from 200W to 1000W. The parameters of a DC power supply 4111 are set, with the DC power supply current adjustment range ranging from 0.2A to 10A. A steady-state magnetic field is provided by a permanent magnet, with the magnetic field strength of the permanent magnet 3111 ranging from 0.5T to 1.8T.

[0063] Example 5:

[0064] The present invention can achieve directional transfer of the melt at the end of a metal wire solely by utilizing ultrasonic vibration to stir the melt and the recoil force generated by metal evaporation. The parameters of the first pulsed laser source 1112, the second pulsed laser source 1122, the third pulsed laser source 1132, and the fourth pulsed laser source 1142 are set, respectively, with the maximum output power of the pulsed lasers ranging from 200W to 4000W, the maximum pulse frequency ranging from 10Hz to 1000Hz, and the laser pulse width ranging from 2 to 50ms. The parameters of the first continuous laser source 1111 are set, with the continuous laser power ranging from 200W to 1000W. The parameters of the ultrasonic generator 6111 are set, with the operating frequency of the ultrasonic generator being 20kHz and the amplitude being 5μm to 100μm.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. For example, changing the heating form of the metal wire to arc heating should also be considered as the scope of protection of the present invention.

Claims

1. Multi-field assisted metal fuse additive melt directional transfer device, characterized in that: Used for laser metal fuse additive manufacturing under microgravity, comprising a laser energy source system, a metal wire feeding system, a constant magnetic field system, an electric field system, a coaxial protective gas system, an ultrasonic generator, a multi-axis motion platform and a forming substrate; the forming substrate is fixedly mounted above the multi-axis motion platform, and the multi-axis motion platform enables the forming substrate to move in multiple degrees of freedom in space; the laser energy source system is fixed above the forming substrate, so that the laser emitted by the laser energy source system irradiates the upper surface of the forming substrate; the metal wire feeding system is fixed on the side of the laser energy source system, and delivers the metal wire to the size range of the laser spot; the constant magnetic field system, the electric field system and the ultrasonic generator are respectively fixed on the metal wire feeding system; the multi-axis motion platform includes four degrees of freedom: X, Y, Z axis motion and platform rotation; The constant magnetic field system includes a permanent magnet, a magnet holder, and a magnetic field measuring instrument; the number of permanent magnets is two, and they are symmetrically arranged on both sides of the end of the metal wire to generate a constant magnetic field. The direction of the magnetic field generated by the permanent magnet is perpendicular to the axial direction of the metal wire; The electric field system includes a DC power supply and a current clamp; there are two current clamps, which are fixed on the metal wire and the forming substrate respectively, and use the DC power supply to form a stable current between the metal wire and the forming substrate; The coaxial protective gas system includes two coaxial protective gas circuits; The laser energy source system includes multiple laser beams, which are generated by multiple laser light sources or a single laser beam generated by a spectroscopic system; the spatial relationship between the laser irradiation position and the metal wire and the forming substrate is adjusted by a position adjustment mechanism; When the multiple laser beams are composed of continuous laser and pulsed laser, the laser energy source system includes a first continuous laser and a first pulsed laser source, and the spatial relationship between the laser irradiation position and the first metal wire and the forming substrate is adjusted by a position adjustment mechanism; The first continuous laser source irradiates the forming substrate through the laser coaxial blowing pipe to form a stable molten pool on the forming substrate. The laser of the first pulsed laser source irradiates the end of the first metal wire to melt the end of the first metal wire to form an end melt and generate recoil pressure on the surface of the end melt to promote the transfer of the end melt to the molten pool on the forming substrate. An ultrasonic generator is installed at a certain distance away from the end of the metal wire. The ultrasonic vibration stirs the end melt, promotes the directional transfer of the end melt from the metal wire to the forming substrate, promotes the melt to separate from the end of the metal wire, and prevents the melt from crawling back along the wire. The constant magnetic field and the electrostatic field form a directional Lorentz force on the melt at the end of the metal wire, promoting the directional transfer of the melt formed at the end of the metal wire to the molten pool.

2. The multi-field assisted metal fuse additive melt directional transfer device according to claim 1, characterized in that: The metal wire feeding system includes a metal wire, a metal wire angle adjustment bracket, an insulating sleeve, a wire coaxial air blowing pipe and a wire feeder; the insulating sleeve and the wire coaxial air blowing pipe are coaxially arranged and installed on the metal wire angle adjustment bracket together with the metal wire; the metal wire angle adjustment bracket is used to adjust the angle between the direction in which the metal wire is fed into the molten pool and the horizontal direction, and ensure that the wire coaxial air blowing pipe is always coaxial with the metal wire; the wire feeder is fixed on the metal wire angle adjustment bracket and is located at the metal wire inlet end of the wire coaxial air blowing pipe, and the position of the wire feeder is synchronously adjusted while adjusting the angle between the direction in which the metal wire is fed into the molten pool and the horizontal direction.

3. The multi-field assisted metal fuse additive melt directional transfer device according to claim 1, characterized in that: The magnet bracket is used to fix the permanent magnet and the wire coaxial blowing pipe; the magnetic field measuring instrument is located between the permanent magnet and the metal wire and is used to measure the magnetic field intensity at the end of the metal wire where the melt is formed.

4. The multi-field assisted metal fuse additive melt directional transfer device according to claim 1, characterized in that: The coaxial protective gas system includes a laser coaxial air blowing pipe, a transparent lens, protective gas, a first flow meter and a second flow meter. Two protective gas paths are designed. The first path is: the laser coaxial air blowing pipe is arranged directly below the first continuous laser source among multiple laser light sources to ensure that the laser light from the first continuous laser source can be vertically and coaxially irradiated onto the forming substrate through the transparent lens. The second path is: the protective gas is ejected through the second flow meter and the wire coaxial air blowing pipe, and the protective gas of the second path is coaxially ejected with the metal wire. The protective gas is an inert gas, and the flow rate of the protective gas entering the laser coaxial air blowing pipe is accurately adjusted by the first flow meter, and the flow rate of the protective gas entering the wire coaxial air blowing pipe is accurately adjusted by the second flow meter.

5. A multi-field assisted metal fuse additive melt directional transfer method, characterized in that: The method is implemented by using the multi-field assisted metal fuse additive melt directional transfer device according to any one of claims 1 to 4, comprising the following steps: Step S1, adjusting the relative positions of the first continuous laser source and the first pulsed laser source of the laser energy source system and the metal wire and the initial processing position of the forming substrate; Step S2: Slice the data according to the three-dimensional model to be constructed, and ensure that the wire feeding direction of the metal wire is always parallel to the forming direction and kept at the front end of the forming direction through the rotational freedom of the multi-axis motion platform; Step S3: sequentially starting the shielding gas, the first continuous laser source, the first pulsed laser source, the DC power supply, and the wire feeder. After the first metal wire contacts the forming substrate, a current loop is generated between the first metal wire and the forming substrate. The current loop is used as a control signal to start additive manufacturing according to the slice trajectory data of the three-dimensional model. Step S4: After processing according to the slice trajectory data in the current forming layer, the wire feeder, DC power supply, laser source and shielding gas are turned off in sequence, and the forming substrate is moved to the initial position of the next trajectory by the multi-axis motion platform; Step S5: Repeat steps S1, S2, S3 and S4 until the entire three-dimensional component is processed.

6. The multi-field assisted metal fuse additive melt directional transfer method according to claim 5, characterized in that: The flow rate of the shielding gas is 0L / min~50L / min; the laser source is used to output pulsed laser or continuous laser, its maximum output power is 4000W, the pulse frequency is 10Hz~1000HZ, the laser pulse width is 2~50ms, and its scanning speed is 50mm / min~2000mm / min; the maximum output current of the DC power supply is 400A; the wire feeder is used to achieve metal wire feeding with a wire diameter of 0.1mm~10mm.

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