WO2020155540A1

WO2020155540A1 - Additive manufacturing device using combined resistance-induction heating of metal wire material

Info

Publication number: WO2020155540A1
Application number: PCT/CN2019/093332
Authority: WO
Inventors: 李波波; 卢秉恒; 张丽娟; 任晓飞; 王强; 李晓强
Original assignee: 西安增材制造国家研究院有限公司
Priority date: 2019-01-28
Filing date: 2019-06-27
Publication date: 2020-08-06
Also published as: CN109676137A

Abstract

The invention relates to an additive manufacturing device using combined resistance-induction heating of a metal wire material, and solves the problem of poor bonding between plugs, layers, and base plates encountered in the manufacturing processes of existing additive manufacturing devices using metal wire materials. The device comprises a wire feeder, a conductive nozzle, a base plate, an atmosphere protection device, and a power supply. The wire feeder, the conductive nozzle, and the base plate are sequentially provided from top to bottom. A positive electrode of the power supply is connected to the conductive nozzle, and a negative electrode is connected to the base plate. The device further comprises an ultrahigh-frequency induction heating device and a base plate heating device. The ultrahigh-frequency induction heating device is a high-frequency induction heating coil. The high-frequency induction heating coil is wound around the wire material at a lower end of the conductive nozzle by means of a ceramic bushing, and is connected to the power supply. A contact temperature measurement element is provided on the ceramic bushing. The base plate heating device is provided below the base plate, and is used to heat the base plate. A base plate temperature measurement element is provided on the base plate, and is used to measure the temperature of the base plate.

Description

Resistance induction composite heating metal wire material additive manufacturing device

Technical field

The invention relates to the field of metal additive manufacturing, in particular to a resistance induction composite heating metal wire additive manufacturing device.

Background technique

Additive manufacturing (AM) technology is based on CAD/CAM design and uses a layer-by-layer accumulation method to manufacture solid parts. Compared with traditional subtractive manufacturing (cutting) technology, it is a material accumulation manufacturing method. Additive manufacturing technology, commonly known as 3D printing technology, is an advanced manufacturing technology that has developed rapidly in the past 30 years. Its advantage lies in the rapid and free manufacturing of three-dimensional structures. It is widely used in new product development and single-piece small-batch manufacturing. Among them, direct metal forming is Difficulties and hot spots in additive manufacturing technology.

There are many traditional methods for direct metal forming, but each has its advantages and disadvantages. The additive manufacturing technology of metal powder as a raw material is not only expensive, but also has the risk of explosion. In the processing process, it is necessary to pay attention to the harm of metal powder to the human body, resulting in higher processing costs. The disadvantages of high-energy beam additive manufacturing technology mainly include high equipment cost, complex equipment structure, relatively large equipment volume, radiation pollution, and low molding efficiency under the same power. For example, the electron beam will be accompanied by the emission of gamma rays during the deposition process. If the device is not designed properly, it will cause radiation leakage and cause environmental pollution; another example is that laser sintering or laser melting technology cannot be applied to all metals, especially for laser reflection. Metals with higher rates have poor forming efficiency. The shortcomings of the electric gusset additive manufacturing technology is that it will produce a lot of noise and arc pollution, and the molding accuracy is also poor. Other metal additive manufacturing methods include direct metal inkjet 3D printing (the Israeli 3D printing start-up XJet has completed the prototype development). This method is limited by the ratio of special metal inks and has a narrow application range.

The metal wire additive manufacturing method based on resistance thermal fusion accumulation molding refers to the use of Joule heat generated by the current flowing in the wire to directly melt the metal wire to realize the metal additive manufacturing process. This technology realizes the direct conversion of electrical energy into heat energy required for metal melting, and the direct use of electrical energy without multiple intermediate conversions can achieve high utilization, high quality, low cost, green and environmentally friendly additive manufacturing of metal parts. It is a kind of material , Machinery, measurement and control technology and information processing integrated metal additive manufacturing method. However, this method is currently less widely used. One of the reasons is its poor stability, serious arcing and splashing during printing, and poor bonding between layers and with substrates.

At present, the metal wire additive manufacturing device has been disclosed, for example, the patent application number 201580075879.9 American Digital Alloy Company. For example, Chinese invention application CN201611186726.4, a resistance electromagnetic induction composite heating metal wire forming method, its basic structure is shown in Figure 1, including metal wire 1, pulsating wire feeding mechanism 2, protective gas 3, gas protective cover 4 , Electromagnetic induction power supply 5, electromagnetic induction coil 6, conductive nozzle 7, three-dimensional motion control system 8, power supply 9, fusion forming parts 10, substrate 11; when the metal wire is formed, it is conveyed to the front end of the metal wire through the nozzle Shielding gas to avoid the oxidation of metal filaments during the melting and accumulation process. The above metal wire additive manufacturing device only illustrates the method of resistance thermal additive manufacturing, but there are the following problems:

1. In the additive manufacturing process of metal microwires formed by resistance thermal fusion accumulation, when the conductive nozzle drives the wire movement, the wire and the conductive substrate are prone to arcing and splashing during the contact process, resulting in poor forming effects, unstable printing, and system Difficult to control and other problems;

2. The wire is softened during the heating process, and the contact tip must be in contact to conduct electricity, resulting in serious problems such as failure to deliver smoothly and blockage during the wire feeding process;

3. Because it is difficult to remelt, the first layer of high-temperature molten metal droplets will form a spherical shape when contacting the low-temperature substrate, and the spherical metal particles cannot be effectively compatible. The same can be pushed to the second to the Nth layer. , Resulting in poor layer-by-layer bonding, and even unable to form. From the theory of metal materials, it is known that the substrate needs a higher temperature (close to the melting point of the metal) to form a metallurgical structure with the molten metal droplets. It is unrealistic to heat the entire substrate to such a high temperature. , The biggest problem of this solution is that the resistance thermal melting can only melt the metal wire itself, but cannot effectively combine with the matrix, resulting in forming defects or even failure;

4. The theory of material wetting in materials science knows that the substrate or the next layer of matrix needs to be heated close to the melting point of the metal to achieve effective infiltration, and heating the substrate to such a high temperature requires a lot of energy first, and the second substrate is so High temperature will cause deformation, instability, flow and collapse, and it is not realistic to rely on substrate heating alone;

5. The uneven temperature field of existing printed items will cause warping, deformation, cracking, and printing defects;

6. Local atmosphere protection cannot achieve good atmosphere protection, and metal oxidation will still occur when the airflow is small; when the airflow is large, the process will be affected, and the airflow will blow the metal droplets away, resulting in forming defects, and for other uncooled The printing area cannot be effectively protected.

Summary of the invention

In order to solve the problems of plugging, poor bonding between layers and substrates in existing metal wire additive manufacturing devices during processing, the present invention provides a resistance induction composite heating metal wire additive manufacturing device.

The technical solution of the present invention is as follows:

A resistance induction composite heating metal wire material additive manufacturing device, comprising a wire feeder, a contact nozzle, a substrate, an atmosphere protection device, and a power supply. The wire feeder, the contact nozzle and the substrate are sequentially arranged from top to bottom. The power supply The positive pole is connected to the contact tip, and the negative pole is connected to the substrate. The special feature is that it also includes an ultra-high frequency induction heating device and a substrate heating device; the ultra-high frequency induction heating device is a high-frequency induction heating coil, The induction heating coil is wound on the outside of the wire at the lower end of the contact nozzle through a ceramic sleeve, and is connected to the power supply; the ultra-high frequency induction heating device is provided with a contact temperature measuring element, and the contact temperature measuring element is arranged on the ceramic sleeve On the tube; the substrate heating device is arranged under the substrate for heating the substrate; the substrate is provided with a substrate temperature measuring element for measuring the temperature of the substrate. Only the substrate heating can not reach the temperature required for material wetting, so a local heater—ultra-high frequency induction heating is also provided under the contact tip to heat the substrate forming area to achieve the metal droplet and matrix Remelting connection, the UHF induction heating coil is fixed on the wire feeder, UHF induction heating can not only realize non-contact heating, but also ensure smooth movement of the moving platform, and has high heating efficiency, which is applicable to all metals.

Further, the high-frequency induction heating coil is a hollow copper tube, and a cooling medium is passed through the hollow copper tube.

Further, it also includes a parallel resistor R1, one end of the parallel resistor R1 is connected to the conductive tip, and the other end is connected to the substrate. The resistance value of the parallel resistor R1 is greater than the contact resistance when the metal wire is connected to the substrate, and smaller than the breakdown resistance of the gas between the contact tip and the substrate, so that the current shunted during normal printing can be negligibly small. Basically no additional system heat loss,

Further, one end of the parallel resistor R1 is connected to the conductive mouth through a wire nose.

Further, the power supply is a programmable power supply, and the programmable power supply has a constant current output mode and a constant voltage output mode. The constant current output mode is used for melting of metal, and the constant voltage output mode is used for powering the parallel resistor R1.

Further, in order to prevent the oxidation of the metal wire and ensure that the protective gas does not affect the metal forming, the atmosphere protection structure includes an airtight box body, an inert gas tank connected with the airtight box body, and the airtight box body and The pipeline connecting the inert gas tank is provided with an air intake pump, and the airtight box is provided with a water and oxygen content detection sensor, and the closed loop of the sensor controls the intake and exhaust of the inert gas; The molten molding area forms an atmosphere protection.

Further, the ceramic sleeve is made of boron nitride or silicon nitride.

Further, the substrate is moved by a three-dimensional motion platform, and a heat sink is provided on the three-dimensional motion platform.

Compared with the prior art, the present invention has the following beneficial effects:

1. In the present invention, an ultra-high frequency induction heating device is arranged under the contact nozzle and above the area to be printed, so as to realize non-contact and high-efficiency heating of the forming area, improve the bond between the metal droplet and the substrate, and benefit the layers and layers. The combination with the substrate realizes high-quality metal 3D forming.

2. The present invention adopts an ultra-high frequency induction heating device. The high-frequency induction heating device realizes rapid non-contact heating of the metal. A strong magnetic field with instantaneous polarity changes is generated in the ultra-high frequency induction coil, and the area to be printed is close to the high-frequency coil , The wire passes through the high-frequency coil, the magnetic beam will penetrate the entire area to be printed, and the corresponding strong eddy current is generated in the direction opposite to the induction heating current inside the induction heating object, because there is resistance in the induction heating metal. The strong eddy current heat energy makes the temperature of induction heating objects rise rapidly, and the heating layer is extremely thin, generally 0.1-0.5mm. Therefore, the UHF induction heating device has the advantages of non-contact high-efficiency heating and high heating efficiency.

3. In the device of the present invention, the contact between the metal wire and the high-frequency induction heating coil causes a short circuit. At the same time, there is a severe temperature gradient between the induction coil and the molten metal, and directly contacts the molten metal, so ceramic sleeves are used for Wire guide and insulation, the ceramic sleeve has the characteristics of not blocking magnetic fields, good thermal shock resistance, and incompatibility with metal droplets. The ceramic sleeve can pass high-frequency magnetic fields well, and because of its incompatibility with metal droplets, it has the advantages of being difficult to plug. At the same time, a temperature measuring device is added to the wall of the casing to solve the difficulty of non-contact temperature measurement in the metal 3D printing process. The contact temperature measurement is simple and convenient, and the temperature measurement is more accurate. At the same time, the molten metal is estimated based on the heat conduction equation. Surface temperature, through the control of resistance welding power supply, high-frequency induction power supply and substrate temperature control power supply to achieve precise control of closed-loop temperature in metal 3D, which helps to achieve high-quality metal 3D forming. Ceramic bushings preferably use boron nitride and silicon nitride .

4. The present invention connects a resistor in parallel between the conductive tip and the substrate. When the wire is separated from the substrate due to some external reason, the parallel resistance creates a path for the current, thereby eliminating the arc and electric spark at the end of the conductive wire. This phenomenon avoids printing failures or major defects caused by violent melting and splashing of materials.

5. The present invention realizes a constant temperature environment in the printing area by heating the substrate by the heater at the bottom of the substrate, which can reduce the warpage and deformation of the printed article and improve the forming quality.

6. In the present invention, an airtight box is provided on the periphery of the printing area and contains an air intake and suction pump and a water and oxygen content detection sensor. The box is equipped with an inert gas tank, which has a simple and reliable structure, accurate monitoring of the atmosphere and stable air pressure , The advantages of good protection effect.

Description of the drawings

Figure 1 is a diagram of an existing metal wire forming device with resistance electromagnetic induction composite heating;

Reference signs: 1-metal wire, 2-pulsating wire feeding system, 3-protective gas, 4-gas protective cover, 5-electromagnetic induction power supply, 6-electromagnetic induction coil, 7-conductive nozzle, 8-three-dimensional motion control System, 9-programmable power supply, 10-fusion forming parts, 11-substrate;

Figure 2 is a diagram of an additive manufacturing device for resistance induction composite heating metal wires of the present invention;

Figure 3 is a structural diagram of the ultra-high frequency induction heating device of the present invention;

4 is a cross-sectional view of the ultra-high frequency induction heating device of the present invention;

Figure 5 is a schematic diagram of the atmosphere protection box of the present invention;

Figure 6 is a schematic diagram of the additive manufacturing process of the metal wire of the present invention.

Reference signs: 21-wire feeder, 22-conduction nozzle, 23-substrate, 24-atmosphere protection device, 25-ultra-high frequency induction heating device, 26-wire, 27-wire nose, 28-ceramic sleeve, 29-Substrate heating device, 30-contact temperature measuring element, 31-radiator, 32-three-dimensional motion platform, 241-airtight box, 242-pump.

detailed description

A resistance induction composite heating metal wire additive manufacturing device as shown in FIG. 2 includes a wire feeder 21, a conductive nozzle 22, a substrate 23, an atmosphere protection device 24 and a power supply, the wire feeder 21, a conductive nozzle 22 and a substrate 23 are arranged in order from top to bottom. The positive pole of the power supply is connected to the contact tip 22, and the negative pole is connected to the substrate 23. It also includes a parallel resistor R1, an ultra-high frequency induction heating device 25 and a substrate heating device 29.

One end of the parallel resistor R1 is connected to the conductive tip 22, and the other end is connected to the substrate 23. One end of the parallel resistor R1 is specifically connected to the conductive tip 22 through the wire nose 27. For the connection of large-current and large-caliber wires, in order to better contact and reduce contact resistance, wire nose 27 is generally used for connection. A parallel resistor of appropriate specifications is connected in parallel between the contact tip 22 and the substrate 23. When the metal wire 26 is separated from the substrate 23 due to some external reason, the parallel resistance creates a path for the current without arcing. The principle of parallel resistance selection is much larger than the contact resistance when the metal wire 26 is turned on (the contact resistance when the metal wire 26 and the substrate 23 are turned on), so that during normal printing, the current shunted can be negligible. There is basically no additional system heat loss. The resistance of the parallel resistance is smaller than the breakdown resistance of the macro protective gas (the gas breakdown resistance between the contact tip 22 and the substrate 23). The parallel resistance is when the metal wire 26 and the substrate 23 are separated Play the role of diversion, and at the same time cooperate with the power control, from constant current to voltage source control, to ensure the minimum output power of the power supply, and further reduce the loss of the circuit. The size and power of the appropriate parallel resistor need to be printed according to different Metal wire 26 to choose.

The specific structure of the print head of the present invention is shown in Figures 3 and 4. The ultra-high frequency induction heating device 25 includes a high frequency induction heating coil. The high frequency induction heating coil is set on the metal wire 26 at the lower end of the contact tip 22 through a ceramic sleeve 28. It is connected to the power supply; the high-frequency induction heating coil can be a hollow copper tube, and the cooling medium is passed into the hollow copper tube. The contact tip 22 connects the resistance welding current to the contact tip 22 through the wire nose 27. The wire feeder 21 feeds the metal wire 26 into the contact tip 22, and continues to feed the high-frequency induction heating coil. The high-frequency induction heating coil passes high-frequency current. , According to the size of the current, different structures can be designed. If the current is too large, the cooling water protection is introduced, because the large current can generate a strong magnetic field. At the same time, due to the existence of resistance, the resistance heat needs to be removed by circulating cold water, and a chiller is required; if If the current is small, it is not necessary. High temperature wires can be used, or air cooling can be used.

The contact between the metal wire 26 and the high-frequency induction heating coil leads to a short circuit. Therefore, a ceramic sleeve 28 is used to guide and insulate the metal wire 26. The ceramic sleeve 28 allows the high-frequency magnetic field to pass through. There is a severe temperature gradient between the molten metal and it is in direct contact with the molten metal. The sleeve has the characteristics of not blocking magnetic fields, good thermal shock resistance, and incompatible with metal droplets, so it has the advantages of not being easy to plug. At the same time, a temperature sensor is added to the casing wall, which solves the difficulty of non-contact temperature measurement in the metal 3D printing process, and realizes the contact temperature measurement simply and conveniently. At the same time, the surface temperature of the molten metal is estimated according to the heat conduction equation. By controlling the resistance welding power supply, High-frequency induction power supply and substrate 23 temperature control power supply realize closed-loop temperature control of metal 3D printing, which helps to achieve high-quality metal 3D forming.

The substrate heating device 29 is provided on the substrate 23 for heating the substrate 23. A temperature measuring element is provided on the substrate 23 for measuring the temperature of the substrate 23. The temperature control power supply part of the substrate 23 realizes a constant temperature environment in the printing area, which can reduce the warpage and deformation of the printed article due to stress and improve the forming quality. The substrate temperature control system can adopt various heating and temperature control methods, such as resistance heating or induction heating, etc., and need to add a temperature sensor to realize PID temperature control, and according to different heat treatment processes of different metal materials, different temperatures can be set If the substrate temperature is not high, no heat sink is required, or the substrate cooling is required to directly add cooling and heat dissipation to achieve a constant temperature environment for the substrate.

In order to reduce circuit loss and ensure that the output power of the power supply remains unchanged, the power supply is a programmable power supply. The programmable power supply has a constant current output mode and a constant voltage output mode. The constant current output mode is used for metal melting, and the constant voltage output mode is used for parallel connection. Power supply for resistor R1. In the present invention, when the metal is melted, the required current is relatively large. If the current when the metal is melted is used to supply power to the parallel resistor R1, it will inevitably spend a lot of power; the parallel resistor R1 only plays a role of diversion, therefore, in the present invention The programmable power supply is selected to supply power to the parallel resistor R1 in the constant voltage output mode. At present, the current limit is automatically adjusted to the constant voltage output mode through software. The maximum current and maximum voltage are set in the software, and they are automatically switched according to the load.

The resistance induction composite heating metal wire 26 additive manufacturing control system consists of six parts, namely the UHF power supply control part, the resistance welding control power supply part, the substrate temperature control power supply part, the three-dimensional motion control part, the wire feeding control part and the protective atmosphere Box control part. The three parts of UHF power supply control part, resistance welding control power supply part and substrate temperature control power supply part can also be combined into an integrated power control. The protective atmosphere box control part contains water and oxygen detection sensors, pressure detection sensors and air pump control.

The resistance welding control power supply part provides the electric energy for the melting of the metal wire. It can be produced by the method of DC, AC or pulse, or voltage source or current source, which is generated by the short circuit of the metal wire, mainly according to the characteristics of the melting and forming process of different metal materials. Joule hot-melting metal wire 26, according to different metal wires 26 and different forming efficiency, the general short-circuit resistance flow is selected from 1A-1000A. When the metal wire melts, the resistance changes drastically and nonlinearly. The power is realized through the power closed loop of the power supply. Tracking and matching of load.

The ultra-high frequency power supply part realizes the rapid non-contact heating of the metal. A strong magnetic field with instantaneous polarity change is generated in the ultra-high frequency induction coil, and the area to be printed is close to the high-frequency coil. The metal wire passes through the high-frequency coil, and the magnetic beam Will run through the entire area to be printed. In the direction opposite to the induction heating current inside the induction heating object, a corresponding strong eddy current is generated. Because there is electrical resistance in the metal that is heated by induction, strong eddy current heat energy is generated, which makes the temperature of the induction heated object rise rapidly, and the heating layer is extremely thin, generally 0.1-0.5mm. And can form a closed-loop control of UHF power output by non-contact temperature measuring devices such as infrared thermometers or infrared imagers to achieve local temperature control in the printing area. This part of the temperature control can realize the non-contact and high-efficiency heating of the forming area, which makes up for the problem that resistance welding heating is difficult to achieve the combination of metal droplets and the substrate, and efficiently realizes the mutual fusion combination between layers and between layers and substrates. Realize high-quality metal 3D forming.

The three-dimensional motion control part can be realized by constructing a motion control platform or a robot arm with a motor module.

As shown in Figure 5, the cabinet control part can be designed for atmosphere protection according to different metal materials, including gas purification system, circulation system and gas temperature control system. It needs water and oxygen sensor, pressure sensor, temperature sensor, gas tank, and gas pump. The inlet and outlet control of the air valve can also be designed according to the vacuum-tight chamber, and a vacuum pump is required. The atmosphere protection device 24 may specifically include an airtight box 241, an inert gas tank connected to the airtight box 241, an air pump 242 is provided on the pipeline connecting the airtight box 241 and the inert gas tank, and the airtight box 241 A water and oxygen content detection sensor is installed on it. Different metal materials can be designed with different atmosphere protections. Various gas purity sensors can include sensors such as water and oxygen content, gas pressure, etc., according to different needs, to achieve closed-loop control of gas quality and gas pressure, and can also be designed according to vacuum tight chambers , Need to be equipped with a vacuum pump. The wire feeding speed and movement speed need to match the process parameters.

The energy input part is the power control part, the space motion control part, the print head and wire feed control part and the box air pump control part need to be connected to the printer and the overall control system, and coordinate and control according to the process characteristics of different metal materials.

The movement mechanism of the present invention is arranged at the bottom of the base plate. Considering that the movement platform cannot withstand high temperature for a long time, resulting in deformation and movement inaccuracy, a radiator 31 is provided on the movement platform, and the radiator 31 can be selected according to the failure conditions. Cold, water cooling, semiconductor refrigeration and so on.

The principle of the present invention is based on the resistance heat generated after the metal wire is energized, and the metal wire is melted and formed by the resistance heat. The metal wire is fed into the contact tip 22 through the automatic wire feeder 21, and the contact tip 22 is connected to the positive electrode of the resistance welding power source. The metal substrate 23 is connected to the negative electrode of the resistance welding power source, and the top of the metal wire forms a loop with the substrate 23. A certain form of current is passed to melt the end of the metal wire instantaneously. After melting, metal droplets are deposited on the substrate 23 due to gravity and surface tension. Above, there is a high-frequency induction coil between the contact tip 22 and the substrate 23. The ultra-high-frequency induction power supply generates a strong magnetic field with instantaneous changes in polarity between the molten metal droplet and the substrate 23. This area generates eddy current heat to make the molten metal The drop and the substrate 23 realize a metallurgical combination. With the movement of the substrate 23 and the continuous delivery of the metal wire 26, stacked metal parts can be formed on the substrate 23 to realize metal additive manufacturing. However, during the printing process, since the resistivity of the metal filament changes with temperature, and the material of the metal wire 26 may contain impurities or deformation, resulting in instability during the wire feeding process, etc., the conductive metal wire 26 and the substrate 23 No contact, arc and electric spark will occur at this time, the deposited material will melt and splash violently, resulting in printing failure or large defects. For this reason, the present invention connects the contact tip 22 and the substrate 23 in parallel with parallel resistors of appropriate specifications. When the metal wire 26 and the substrate 23 are separated due to some external reason, the parallel resistors create a path for the current to avoid arcing.

As shown in Figure 6, the printing process of the metal wire additive manufacturing device of the present invention is as follows:

1. According to the needs of the molded parts, determine the properties of the molding material and various process parameters of the molding, and ensure that the surface of the metal wire 26 is free of oxides and dry treatment.

2. Use an atmosphere protection structure to achieve a protective atmosphere or a vacuum environment, and feed the metal wire 26 into the conductive nozzle 22 through the wire feeder 21 structure, and keep in contact with the substrate 23.

3. Start the printer according to the preset parameters. Under the coordinated work of the movement mechanism, the temperature control power supply of the substrate 23, the resistance welding power supply and the high-frequency induction heating power supply, and the wire feeder 21, the metal materials are accumulated and formed layer by layer to realize the metal Additive manufacturing of parts.

Claims

A resistance induction composite heating metal wire material additive manufacturing device, comprising a wire feeder (21), a contact tip (22), a substrate (23), an atmosphere protection device (24) and a power supply. The wire feeder (21) , The conductive tip (22) and the substrate (23) are arranged in order from top to bottom, the positive pole of the power supply is connected to the conductive tip (22), and the negative pole is connected to the substrate (23), characterized in that:

It also includes an ultra-high frequency induction heating device (25) and a substrate heating device (29);

The ultra-high frequency induction heating device (25) is a high frequency induction heating coil, and the high frequency induction heating coil is wound on the outside of the metal wire (26) at the lower end of the contact tip (22) through a ceramic sleeve (28), and Connected to the power supply; the ceramic bushing (28) is provided with a contact temperature measuring element (30);

The substrate heating device (29) is arranged under the substrate (23) for heating the substrate (23); a substrate temperature measuring element is arranged on the substrate (23) for measuring the temperature of the substrate (23).
The resistance induction composite heating metal wire additive manufacturing device according to claim 1, wherein the high frequency induction heating coil is a hollow copper tube, and a cooling medium is passed into the hollow copper tube.
The resistance induction composite heating metal wire additive manufacturing device according to claim 1 or 2, characterized in that it further comprises a parallel resistor R1, one end of the parallel resistor R1 is connected to the contact tip (22), and the other end is connected to the substrate (23) Connection, the resistance value of the parallel resistor R1 is greater than the contact resistance when the metal wire (26) is connected to the substrate (23), and smaller than the breakdown resistance of the gas between the contact tip (22) and the substrate (23) .
The resistance induction composite heating metal wire additive manufacturing device according to claim 3, wherein one end of the parallel resistor R1 is connected to the conductive tip (22) through a wire nose (27).
The resistance induction composite heating metal wire additive manufacturing device according to claim 4, wherein the power supply is a programmable power supply, and the programmable power supply has a constant current output mode and a constant voltage output mode, and a constant current output The mode is used for the melting of metal, and the constant voltage output mode is used for the power supply of parallel resistor R1.
The resistance induction composite heating metal wire additive manufacturing device according to claim 5, characterized in that: the atmosphere protection device (24) comprises an airtight box (241), connected to the airtight box (241) An inert gas tank, a pipeline connecting the airtight box (241) and the inert gas tank is provided with an air pump (242), and the airtight box (241) is provided with a water and oxygen content detection sensor.
The resistance induction composite heating metal wire additive manufacturing device according to claim 6, wherein the ceramic sleeve (28) is made of boron nitride or silicon nitride.
The resistance induction composite heating metal wire additive manufacturing device according to claim 7, wherein the substrate (23) is moved by a three-dimensional motion platform (32), and the three-dimensional motion platform (32) is provided with heat dissipation器(31).