A flux-assisted arc-based additive system and method

Abstract

The application is a kind of flux-assisted electric arc additive system and method. It includes a robot additive manufacturing device, a flux-assisted electric arc additive device, an infrared temperature measuring device and a closed-loop feedback control device. The flux-assisted electric arc additive mechanism includes an electromagnetic vibrating flux conveying device, a flux conveying hopper, a substrate enclosure and a variable frequency electromagnetic vibration table. The substrate is placed on the variable frequency electromagnetic vibration table, and the substrate enclosure is set around the substrate. The electromagnetic vibrating flux conveying device conveys flux to the substrate enclosure of the N-layer additive through the flux conveying hopper. The variable frequency electromagnetic vibration table vibrates to make the upper surface of the flux level with the upper surface of the previous layer of additive workpiece. The flux particles serve as a support structure and can be used for additive inclined structural members and suspended structural members. This application avoids problems such as damage to the displacement machine caused by stress accumulation of the additive workpiece during the electric arc additive process, reduces the cost of production equipment and ensures the quality of the formed parts.

Description

Technical Field

[0001] This invention belongs to the field of metal additive manufacturing, specifically relating to a flux-assisted arc additive manufacturing system and method. Background Technology

[0002] Arc additive manufacturing technology, based on the principle of layer-by-layer deposition, utilizes an electric arc as a heat source and typically employs filament as the additive material. Through process control technology, it gradually builds up points, lines, and surfaces, eventually creating complex additive structural components in a three-dimensional form. It is a relatively advanced new intelligent manufacturing technology. Compared to other additive manufacturing methods, arc additive manufacturing offers advantages such as high additive efficiency, low manufacturing cost, a wide range of filament selection, high utilization rate, and no special restrictions on the structural dimensions of the prototype. It can be used for the manufacturing of large-scale, complex structural components and functional-structural integrated parts. Furthermore, it can be combined with other auxiliary devices to achieve intelligent, digital, and parallel manufacturing.

[0003] Arc additive manufacturing is a supportless process. When adding complex structural parts, a positioner can often be used to change the position of the additive workpiece, allowing it to grow vertically upwards. However, adding a positioner increases equipment costs. Furthermore, due to the rapid temperature changes during arc additive manufacturing, repeated cooling and heating during the forming process cause uneven expansion and contraction of the material. The temperature gradient and thermal cycling effect caused by layer-by-layer stacking make the additive workpiece prone to significant stress. This stress is transmitted to the positioner through the substrate, potentially reducing the positioner's lifespan or even causing damage. While some additive workpieces with small tilt angles can be directly offset and formed using a dedicated additive manufacturing gun, this requires high operational skills and is prone to molten metal flow during forming, making it unsuitable for the preparation of highly fluid metals. Summary of the Invention

[0004] The purpose of this invention is to provide a flux-assisted arc additive manufacturing system and method.

[0005] The technical solution to achieve the purpose of this invention is: a flux-assisted arc additive manufacturing system, including a robotic additive manufacturing device, a flux-assisted arc additive manufacturing device, an infrared temperature measuring device, and a closed-loop feedback control device.

[0006] The flux-assisted arc additive manufacturing mechanism includes an electromagnetic vibration flux conveying device, a flux conveying hopper, a substrate enclosure, and a frequency conversion electromagnetic vibration table.

[0007] The substrate used for additive manufacturing is placed on a frequency-converting electromagnetic vibration table. The substrate is surrounded by a substrate enclosure. The electromagnetic vibration flux conveying device conveys flux into the substrate enclosure, which has been additively layered with N layers, through a flux conveying hopper. The frequency-converting electromagnetic vibration table vibrates to make the upper surface of the flux level with the upper surface of the previous layer of additive workpiece.

[0008] Furthermore, it also includes infrared temperature measurement devices and closed-loop feedback control devices;

[0009] The infrared temperature measuring device is fixed to one side of the substrate by a tooling fixture, and the temperature measuring range is 0℃~1500℃. It is used to obtain the temperature of the additive workpiece.

[0010] The closed-loop feedback control device calculates the volume of flux required below the Nth layer of metal based on the surrounding perimeter and the volume of the additive metal. It then delivers the flux and controls it to be poured evenly from below the funnel onto the substrate inside the perimeter. The variable frequency electromagnetic vibration table is activated, causing the substrate and the additive workpiece to vibrate at the same frequency, ensuring that the surface of the flux is level with the surface of the previous layer of additive workpiece. The closed-loop feedback control device also receives the temperature of the additive workpiece measured by an infrared thermometer.

[0011] Furthermore, the robotic additive manufacturing apparatus includes: an additive power supply, an additive robot arm, an additive gun, a wire feeder, a protective gas device, and a control system for controlling the additive motion trajectory of the additive robot arm;

[0012] The electromagnetic vibration flux conveying device is fixed above the substrate by a tooling fixture. It is adjustable in the X, Y, and Z directions. The electromagnetic vibration flux conveying device has an amplitude of 1.5 mm, a vibration frequency of 3000±100 r / min, and a power of 5~50W.

[0013] The frequency of the variable frequency electromagnetic vibration table is 1-600 Hz, the amplitude is 1-5 mm, the load is 80 kg, the vibration acceleration is 20 g, and it has a built-in PLC adjustment function.

[0014] A method for additive manufacturing using the above-mentioned electric arc additive system includes the following steps:

[0015] Step (1): Plan the additive manufacturing path;

[0016] Step (2): Pre-treatment of the substrate surface, setting up substrate enclosures around the substrate, and assembling the system;

[0017] Step (3): Start arcing from one end to perform single-layer reciprocating additive manufacturing, and arc additive manufacturing the Nth layer of metal on the substrate, N = 1, 2, 3...;

[0018] Step (4): The closed-loop feedback control device calculates the volume of flux required below the Nth layer of metal, delivers flux and controls the flux to be poured evenly from below the flux delivery hopper onto the metal substrate inside the enclosure, starts the frequency conversion electromagnetic vibration table, drives the substrate and additive workpiece to vibrate at the same frequency, so that the upper surface of the flux is level with the upper surface of the previous layer of additive workpiece.

[0019] Step (5): The temperature of the additive workpiece is obtained by using an infrared temperature measuring device. The closed-loop feedback control device receives the temperature of the additive workpiece measured by the infrared temperature measuring device and makes online adjustments. After the workpiece is cooled to the preset temperature, a control command is sent to the robot additive manufacturing platform to perform the N+1 layer of additive manufacturing.

[0020] Step (6): Repeat steps (3)-(5) until the integrated additively formed part is obtained.

[0021] Furthermore, the flux used in additive manufacturing consists of spherical particles with a diameter of 1.5 to 2.5 mm. The melting point of the flux must be 100 ± 10 °C lower than the melting point of the welding wire, and the volumetric mass of the flux slag must not exceed 3% of the volumetric mass of the molten metal in the molten pool.

[0022] Furthermore, the additively formed part is an aluminum alloy part, and the flux is an aluminum-silicon alloy flux particle containing one or more of aluminum, silicon, magnesium, sodium, zirconium and potassium.

[0023] Furthermore, the additively formed part is a stainless steel part, and the flux is a smelted low-manganese, high-silicon, medium-fluorine flux particle with added silicon, manganese, aluminum, titanium and vanadium (one or more).

[0024] Furthermore, the additively formed part is a titanium alloy part, and the flux is a titanium-aluminum type flux particle composed of elements such as titanium, aluminum, molybdenum, nickel, and chromium.

[0025] Furthermore, the required flux volume below the Nth metal layer in step (4): V 焊剂 =W×L×H-π×R 2 ×P×T, where W and L are the length and width inside the substrate enclosure, respectively, H is the height of the Nth metal layer in the additive manufacturing process, T is the time for the Nth metal layer in the additive manufacturing process, the wire feeding speed of the wire feeder is P, and the radius of the welding wire is R.

[0026] Furthermore, the shape of the additively formed part can be an additively inclined structural part or a suspended structural part.

[0027] Compared with the prior art, the significant advantages of this invention are:

[0028] (1) This invention proposes an arc additive manufacturing device based on flux assistance, which has a reasonable structural design, is simple and has strong applicability; the Nth layer (initially N=1) of metal is formed by arc additive manufacturing on the substrate. The volume of flux required below the Nth layer of metal is calculated based on the volume of the enclosure and the additive metal. The same volume of flux is evenly poured onto the metal substrate inside the enclosure using a flux delivery device. The vibration table is started to drive the substrate and the additive workpiece to achieve synchronous vibration, so that the upper surface of the flux is horizontal with the upper surface of the first layer of additive workpiece.

[0029] (2) When adding metal to the upper layer, the flux particles below can serve as a support structure, playing a role in supporting the additive workpiece and the additive weld during the additive process; it can be used for additive inclined structural parts and suspended structural parts, so that the additive process can complete the arc additive manufacturing of any complex structure without the use of a positioner, avoiding the problem of stress gradually accumulating inside the part due to repeated cooling and heating during the arc additive process and being transmitted to the positioner through the substrate, resulting in reduced life or even damage, and further reducing the cost of additive production equipment; especially for metals with high fluidity, molten metal is prone to flow during the additive forming process, and flux particles can serve as a support structure to assist arc additive manufacturing and ensure the forming rate.

[0030] (3) Adding flux protection during the forming process can effectively remove oxides that appear during the additive manufacturing process, reduce the melting point and surface tension of the molten pool. The flux melts into slag on the surface under the action of the electric arc, protecting the molten metal from the intrusion of gas in the surrounding atmosphere into the molten pool when it is in the liquid state, thereby reducing defects such as porosity and inclusions in the additive workpiece process.

[0031] (4) The flux consists of spherical particles with a diameter of 1.5 to 2.5 mm. During the additive manufacturing process, the repeated cooling and heating process causes the internal thermal stress of the part to gradually accumulate. The flux particles can promptly conduct the generated heat to the surrounding particles, helping the additive workpiece to dissipate heat. This can effectively reduce the thermal stress of the part so as not to damage the integrity of the additive workpiece or material.

[0032] (5) For special wire materials, flux particles containing special elemental components can be selected to transfer the necessary metal elements to the molten pool, further improving the structure and ensuring the performance of additive workpieces.

[0033] (6) The closed-loop feedback control device can calculate the volume of flux required below the Nth layer of metal based on the surrounding perimeter and the volume of the additive metal. It controls the flux feeding amount online using a high-precision controller, delivering the same volume of flux and controlling the flux to be evenly poured from below the funnel onto the metal substrate inside the perimeter. It then starts the frequency conversion electromagnetic vibration table, causing the substrate and the additive workpiece to vibrate at the same frequency, ensuring that the surface of the flux is level with the surface of the previous layer of additive workpiece. The closed-loop feedback control device can receive information such as the temperature of the additive workpiece measured by an infrared thermometer and process the data online, comparing it with the set temperature. Once the workpiece cools to the preset temperature, it sends a control command to the additive manufacturing device to perform the N+1th layer of additive manufacturing. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0035] Figure 2 This is a schematic diagram of the robot additive manufacturing platform of the present invention.

[0036] Figure 3 This is a schematic diagram of the flux-assisted arc additive closed-loop feedback control device of the present invention.

[0037] Figure 4 This is a schematic diagram of the closed-loop feedback control of interlayer temperature in electric arc additive manufacturing according to the present invention.

[0038] Figure 5 Simplified model diagram of the molten pool stress before and after flux-assisted additive manufacturing of an inclined workpiece; where (a) is without flux assistance and (b) is with flux assistance.

[0039] Figure 6 This is a schematic diagram of a flux-assisted arc additive suspended structure model.

[0040] Attached Figure Labeling Explanation

[0041] 1-Additive power supply, 2-Additive robot arm, 3-Additive gun, 4-Wire feeder, 5-Protective gas device, 6-Control cabinet, 7-Teach pendant, 8-Electromagnetic vibration flux conveying device, 9-Fluorescence conveying hopper, 10-Infrared temperature measuring device, 11-Substrate enclosure, 12-Substrate, 13-Variable frequency electromagnetic vibration table, 14-Closed-loop feedback control device. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings.

[0043] This invention relates to a flux-assisted arc additive manufacturing apparatus and process. The process involves arc additive manufacturing of the Nth layer (initially N=1) of metal on a substrate. Based on the surrounding perimeter and the volume of the additive metal, a closed-loop feedback control device calculates the required flux volume below the Nth layer. An electromagnetic vibration flux delivery device evenly pours the same volume of flux onto the metal substrate inside the perimeter. A variable frequency electromagnetic vibration table is activated, causing the substrate and the additive workpiece to vibrate at the same frequency, ensuring the flux surface is level with the upper surface of the upper additive workpiece. Then, the N+1th layer of additive manufacturing is performed. The flux particles serve as a support structure, suitable for manufacturing inclined or suspended structures. This allows for the arc additive manufacturing of arbitrarily complex structures without the need for a positioner, avoiding stress buildup in the additive workpiece that could damage the positioner and reducing equipment costs. Particularly beneficial for highly fluid metals, which are prone to molten metal flow during additive manufacturing, the flux particles act as a support structure to assist arc additive manufacturing and ensure a high forming rate. Under the action of an electric arc, the flux melts into a surface slag, protecting the liquid from the influence of external gases and effectively preventing porosity and inclusions in the additive workpiece. Simultaneously, the flux particles promptly conduct the generated heat to surrounding particles, aiding in heat dissipation from the additive workpiece and thus effectively reducing thermal stress.

[0044] like Figures 2-4As shown, a flux-assisted arc additive manufacturing device includes a control system, a robotic additive manufacturing platform, a flux-assisted arc additive manufacturing device, an infrared temperature measuring device 10, and a closed-loop feedback control device 14.

[0045] The robotic additive manufacturing platform includes: additive power supply 1, additive robot arm 2, additive gun 3, wire feeder 4, protective gas device 5, control cabinet 6, and teach pendant 7, etc. (see...) Figure 2 );

[0046] The flux-assisted arc additive manufacturing device includes: an electromagnetic vibration flux conveying device 7, a flux conveying hopper 9, a substrate enclosure 11, and a frequency conversion electromagnetic vibration table 13 (see...). Figure 3 );

[0047] The control system regulates the additive manufacturing robot's robotic arm 2, wire feeder 4, protective gas device 5, and additive gun 3, etc.

[0048] The teach pendant 7 is a remote control used to memorize and store the mechanical movement behavior of the additive robot arm. It can realize human-machine interaction. The additive robot arm performs additive manufacturing under the human control of the teach pendant. After a single layer of additive manufacturing is completed, the control system controls the additive robot arm to move upward to a safe position above the additive workpiece 15.

[0049] The electromagnetic vibration flux conveying device 7 is mounted on the base platform by tooling fixtures. The X / Y / Z directions are adjustable. The flux particles can be poured into the substrate enclosure 11 through the flux conveying hopper 9. The closed-loop feedback control device 14 regulates the flux conveying efficiency and feeding amount of the electromagnetic vibration flux conveying device 7.

[0050] The electromagnetic vibration flux conveying device 7 has an amplitude of 1.5mm, a vibration frequency of 3000r / min, and an adjustable power of 5~50W. It can be connected to a closed-loop feedback control device to achieve online control. It has a built-in high-precision controller to automatically adjust the flux feeding amount and can convey flux and control the flux to flow out evenly from below the flux conveying hopper.

[0051] The substrate enclosure is placed around the substrate and is preferably mechanically connected to it. It can be stacked in segments along its height and must be higher than the additive workpiece. It supports the solder around the substrate. The shape of the enclosure can be designed individually according to the shape of the additive workpiece, and can be selected and adjusted accordingly based on the specific shape of the additive workpiece.

[0052] The frequency and amplitude of the variable frequency electromagnetic vibration table are adjustable. The frequency adjustment range is 1~600HZ, the amplitude adjustment range is 1~5mm, the load is 80kg, the vibration acceleration is 20g, and the built-in PLC adjustment function and digital circuit control the vibration table to vibrate at the same frequency as the additive sample, so that the upper surface of the flux is level with the upper surface of the previous layer of additive workpiece, and the flatness is ±2mm.

[0053] The infrared temperature measuring device is fixed to one side of the base by tooling fixtures. The temperature measuring range is 0℃~1500℃. The temperature data of the additive workpiece can be obtained by adjusting the position.

[0054] The closed-loop feedback control device calculates the required flux volume below the Nth layer of metal based on the surrounding perimeter and the volume of the additive metal. It then automatically adjusts the flux feed rate using a high-precision controller, delivering the same volume of flux and controlling its even pouring from below the funnel onto the metal substrate inside the perimeter. The device also activates a variable-frequency electromagnetic vibration table, causing the substrate and the additive workpiece to vibrate at the same frequency, ensuring the flux surface is level with the surface of the previous additive workpiece. The closed-loop feedback control device receives information such as the additive workpiece temperature measured by an infrared thermometer, processes the data online, and compares it with the set temperature. Once the workpiece cools to the preset temperature, it sends a control command to the robotic additive manufacturing platform to perform the N+1th layer of additive manufacturing.

[0055] In actual additive manufacturing processes, the forming of tilted workpieces largely depends on the stress state of the molten pool during additive manufacturing. The stress model of the molten pool during the additive manufacturing of tilted workpieces is as follows: Figure 5 As shown in (a), when the normal support force F N The surface tension σ cannot overcome the gravity G of the molten metal in the pool, the additional pressure Pc of the curved liquid surface, the arc force Fa, and the droplet impact force F. b Due to the influence of flux, the combined force on the molten pool is not zero, and it is in an unsteady state. Before solidification, it flows and drips, easily causing collapse. The force model of the molten pool after flux-assisted additive manufacturing is as follows: Figure 5 As shown in (b), during additive manufacturing of the upper metal layer, the flux particles below can act as a supporting structure, supporting the molten pool during the additive manufacturing process. Normal support force F N and surface tension σ and the supporting force F of flux particles on the molten pool N2 When the molten pool can overcome the influence of gravity G of the liquid metal, additional pressure Pc of the curved liquid surface, arc force Fa and droplet impact force Fb, and reach a quasi-steady state, it can be considered that the comprehensive force it is subjected to is 0, the molten pool is in a balanced and stable state, the molten pool slowly solidifies and the surface does not collapse.

[0056] The technical solution for achieving the objective of this invention is: a flux-assisted arc additive manufacturing process, comprising the following steps:

[0057] Step (1): First, perform partitioned and layered modeling based on the geometric model of the additive workpiece, and rationally plan the robot's additive path, posture, and process;

[0058] Step (2): Polish the substrate surface to remove the oxide film, clean the substrate surface with acetone reagent, set up a barrier around the substrate, preferably mechanically connected to the substrate and detachable;

[0059] Step (3): Use a fixture to assemble and fix the substrate on the frequency conversion electromagnetic vibration table. Adjust the position to make the two fit tightly together. The substrate and the additive workpiece can be driven to vibrate together at a certain frequency and amplitude. The electromagnetic vibration flux delivery device is fixed on the base with a tooling fixture. The X / Y / Z directions are adjustable. The flux particles can be poured into the substrate enclosure through the flux delivery hopper. The infrared temperature measuring device is fixed on one side of the base with a tooling fixture. The position is adjusted for the temperature measurement of the additive workpiece.

[0060] Step (4): Call the program, set the additive process parameters, and the control system uses the additive robot to drive the additive gun to perform single-layer reciprocating additive processing from one end along the set additive path. According to the process requirements, the Nth layer (initially N=1) of metal is formed by electric arc additive processing on the substrate. After the additive processing is completed, the control system controls the additive robot to move upward to above the additive workpiece.

[0061] Step (5): Based on the volume of the surrounding perimeter and the additive metal, the closed-loop feedback control device calculates the volume of flux required below the Nth layer of metal. The online high-precision controller automatically adjusts the flux feeding amount, conveys the same volume of flux, and controls the flux to be evenly poured from below the flux hopper onto the metal substrate inside the perimeter. The frequency conversion electromagnetic vibration table is started, causing the substrate and the additive sample to vibrate at the same frequency, so that the upper surface of the flux is level with the upper surface of the previous layer of additive sample, with a flatness of ±2mm (see...). Figure 3 );

[0062] Step (6): The temperature of the additive workpiece is obtained using an infrared thermometer. The closed-loop feedback control device receives the temperature of the additive workpiece measured by the infrared thermometer and processes the data online, comparing it with the set temperature. After the workpiece cools to the preset temperature, a control command is sent to the robot additive manufacturing platform to perform the N+1th layer of additive manufacturing (see...). Figure 4 );

[0063] Step (7): Repeat steps (4), (5), and (6) until an integrated additively formed workpiece is obtained;

[0064] Step (8): Remove the substrate enclosure, clean the flux slag, and cut the additive sample off the substrate.

[0065] In an arc additive manufacturing process, the Nth layer (initially N=1) of metal is formed on a substrate. The required flux volume below the Nth layer is calculated based on the enclosure and the volume of the additive metal. A flux delivery device evenly pours the same volume of flux onto the metal substrate inside the enclosure. A vibrating table is used to ensure the flux surface is level with the surface of the first layer of the additive workpiece. For highly fluid metals, molten metal flow is prone to occur during additive manufacturing. While the molten pool remains stable in the first layer, it cannot remain stable in higher layers and flows. Adding flux particles as a support structure can change the molten pool constraint state at the contact point with the flux particles, supporting the additive workpiece and weld beads during the additive process. The flux particles can serve as a support structure for adding inclined or suspended structural parts. This allows for arc additive manufacturing of arbitrarily complex structures without the need for a positioner, avoiding the problems of stress accumulation within the part due to repeated cooling and heating during arc additive manufacturing, which is then transmitted to the positioner via the substrate, reducing its lifespan or even causing damage. This further reduces the cost of additive manufacturing equipment. Adding flux to the additive manufacturing process helps to conduct the heat generated during the additive manufacturing process to the surrounding particles, which helps the additive workpiece dissipate heat. This can effectively reduce the thermal stress of the additive workpiece, prevent the molten pool at higher layers from overflowing due to overheating or stress instability, and ensure that the morphology of the upper and lower layers is relatively similar.

[0066] Adding flux during the forming process effectively removes oxides generated during additive manufacturing, reduces the melting point and surface tension of the molten pool, and the flux melts into a surface slag under the action of an electric arc. This protects the molten metal from atmospheric gases intruding into the molten pool while it is in a liquid state, thereby reducing defects such as porosity and inclusions in the additive workpiece. The flux consists of spherical particles with a diameter of 1.5–2.5 mm. During the repeated cooling and heating process in additive manufacturing, thermal stress gradually accumulates inside the part. The flux particles can promptly conduct the generated heat to the surrounding particles, helping the additive workpiece dissipate heat and thus effectively reducing the thermal stress of the part.

[0067] When the flux melting point is too high, the slag formed by arc melting will affect the metallurgical reaction between the molten metal droplets and the molten pool metal, potentially leading to defects such as inclusions and porosity during additive manufacturing. Therefore, when selecting flux particles, the flux melting point must be 100°C lower than the welding wire melting point. The volumetric mass of the slag directly affects its floating speed, fluidity, and the likelihood of inclusions in the molten metal. When the contact area between the slag and the molten metal / gas is large, the slag will generate a strong stirring effect on the molten pool, which is beneficial for the metallurgical reaction. However, if the slag volumetric mass is large, it cannot float to the surface of the molten pool in time before solidification, remaining as inclusions in the additively formed metal, thus causing additive manufacturing defects and reducing its mechanical properties. To avoid such situations, a flux with a slag volumetric mass not exceeding 3% of the molten pool metal volumetric mass can be selected. In this case, the molten metal can flow smoothly into the weld gap, while the slag floats on the surface, thereby reducing defects generated during additive manufacturing.

[0068] In the additive manufacturing of aluminum alloys, aluminum-silicon alloy flux particles containing elements such as aluminum, silicon, magnesium, sodium, zirconium, and potassium can be selectively added. These elements play a crucial role in aluminum alloy additive manufacturing, directly or through displacement reactions transferring the required alloying elements to the molten pool metal during arc melting. During the additive manufacturing process, these elements can diffuse into the molten pool via arc melting. The aluminum element in the aluminum-silicon alloy flux particles can significantly improve the strength, hardness, and corrosion resistance of the additive workpiece. Silicon, on the other hand, makes the aluminum alloy additive workpiece harder and tougher, while reducing the coefficient of thermal expansion, thus improving its mechanical properties. The addition of magnesium helps enhance the fluidity between areas in the aluminum alloy additive manufacturing process and improves the strength, stiffness, and ductility of the aluminum alloy additive workpiece. Furthermore, the application of zirconium in the flux particles can improve the corrosion resistance and hot cracking resistance of the aluminum alloy additive workpiece. The content of sodium or potassium has a significant impact on the mechanical properties of the aluminum alloy additive workpiece; they can enhance its strength and hardness, while also helping to reduce the coefficient of thermal expansion. Oxides, as additives in flux particles, can reduce oxidation of additive workpieces, thereby improving additive manufacturing efficiency and forming quality.

[0069] In additive manufacturing of stainless steel, smelted low-manganese, high-silicon, medium-fluorine flux particles containing elements such as silicon, manganese, aluminum, titanium, and vanadium can be selected. Throughout the additive manufacturing process, these elements gradually diffuse into the molten pool through arc melting. Silicon reacts with oxygen to form a dense silicon oxide layer, thereby improving the thermal stability, corrosion resistance, and oxidation resistance of stainless steel. Furthermore, the addition of elements such as manganese and vanadium can enhance the strength and hardness of the additive workpiece and further influence the additive quality by controlling grain growth. Fluorine in the stainless steel additive manufacturing process mainly improves the material's corrosion resistance, wear resistance, and friction reduction properties by forming a fluoride layer on the formed surface. Additionally, elements such as titanium and niobium help form a stable oxide film on the surface of the additive workpiece, thereby improving the corrosion resistance of stainless steel and endowing the stainless steel additive workpiece with ideal performance characteristics.

[0070] In the additive manufacturing of titanium alloys, titanium-aluminum type flux particles composed of elements such as titanium, aluminum, molybdenum, nickel, and chromium are typically selected. These elements can diffuse into the molten pool during the additive manufacturing process. Titanium is the main element in titanium-aluminum type fluxes, significantly improving the strength and hardness of the additive workpiece and giving it good corrosion resistance and high-temperature resistance. Adding aluminum to the flux particles improves the wettability and flowability of the additive region. Simultaneously, aluminum also enhances the strength and hot-cracking resistance of the additive region. Furthermore, molybdenum in the flux is also important, further improving the corrosion resistance, strength, and hardness of the titanium alloy additive workpiece.

[0071] To further verify the effect, multiple sets of comparative experiments were conducted, with parameters remaining consistent in each experimental case. The following example illustrates this: The specific steps of the implementation plan are as follows:

[0072] 1) Using CMT (Continuous Metallurgical Mass Production) arc additive manufacturing technology, a high-strength aluminum alloy suspended structure is additively manufactured on an ER5356 aluminum alloy substrate with a geometric dimension of 440×220×10mm using ER5356 aluminum alloy wire with a diameter of 1.2mm. The distance between the two ends of the suspended structure is 187mm, the model width is 100mm, and the total height is 82.4mm (see...). Figure 6 The substrate surface is polished and cleaned with acetone. A barrier with dimensions of 240mm, 160mm and 120mm is set around the substrate.

[0073] 2) Based on the selected ER5356 aluminum alloy wire, the corresponding interlayer temperature is preset to 90℃ in the closed-loop feedback system control device;

[0074] 3) The substrate is assembled and fixed using a fixture on the frequency conversion electromagnetic vibration table. The electromagnetic vibration flux delivery device is fixed on the base with a tooling fixture. The wire feeder adopts the pulse wire feeding mode. The infrared temperature measuring device is fixed on one side of the base with a tooling fixture. The position and instrument parameters are adjusted for the temperature measurement of the additive workpiece.

[0075] 4) The CMT arc additive manufacturing equipment is turned on, the additive gun is powered on, the program is called, and the additive manufacturing process parameters matching the ER5356 aluminum alloy wire are set according to the expert process library. The key parameters are as follows: the protective gas is 100% Ar, the current is 125A, the voltage is 10.4KV, the gas supply speed is 25L / min, the wire feeding speed is 9.2m / min, and the additive gun travel speed is 8mm / s. The control system uses the additive robot arm to drive the additive gun to perform single-layer reciprocating additive manufacturing from one end along the set additive path. According to the process requirements, the Nth layer (initially N=1) of metal is formed on the substrate by arc additive manufacturing. After the additive manufacturing is completed, the control system controls the additive robot arm to move upward to a safe position 600mm above the workpiece.

[0076] 5) Select aluminum-silicon alloy spherical flux particles with a diameter of 2mm. Calculate the required flux volume below the Nth layer of metal based on the surrounding enclosure and the volume of the additive metal using a closed-loop feedback control device. Convey the same volume of flux and control the flux to be evenly poured from below the flux hopper onto the metal substrate inside the enclosure. Start the frequency conversion electromagnetic vibration table to drive the substrate and additive sample to vibrate at the same frequency, ensuring that the upper surface of the flux is level with the upper surface of the previous layer of additive workpiece.

[0077] 6) An infrared thermometer acquires the temperature of the additive workpiece. A closed-loop feedback control device receives the temperature information measured by the infrared thermometer and processes the data online, comparing it with the set temperature. After the workpiece cools to the preset temperature, a control command is sent to the robotic additive manufacturing platform to perform the N+1th layer of additive manufacturing.

[0078] 7) Repeat steps (4), (5), and (6) until the integrated electric arc additive suspended structure workpiece is obtained;

[0079] Experimental results: The ER5356 aluminum alloy suspended structure workpiece prepared by flux-assisted arc additive manufacturing process has a smooth and flat surface, regular layering, and no defects such as deformation, cracking, or slag inclusion. During the additive manufacturing of the suspended structure, no molten pool flow occurred in the inclined structure where the flux particles were supported at the offset.

Claims

1. A flux-assisted arc additive manufacturing system, characterized in that, Including robotic additive manufacturing equipment, flux-assisted arc additive manufacturing equipment, infrared temperature measurement equipment, and closed-loop feedback control equipment; The flux-assisted arc additive manufacturing device includes an electromagnetic vibration flux conveying device, a flux conveying hopper, a substrate enclosure, and a frequency conversion electromagnetic vibration table. The substrate used for additive manufacturing is placed on a frequency-converting electromagnetic vibration table. The substrate is surrounded by a substrate enclosure. The electromagnetic vibration flux conveying device conveys flux into the substrate enclosure that has been additively layered N layers through a flux conveying hopper. The frequency-converting electromagnetic vibration table vibrates to make the upper surface of the flux level with the upper surface of the previous layer of additive workpiece. It also includes an infrared temperature measurement device and a closed-loop feedback control device; The infrared temperature measuring device is fixed to one side of the substrate by a tooling fixture, and the temperature measuring range is 0℃~1500℃. It is used to obtain the temperature of the additive workpiece. The closed-loop feedback control device calculates the volume of flux required below the Nth layer of metal based on the surrounding perimeter and the volume of the additive metal. It then delivers the flux and controls it to be poured evenly from below the hopper onto the substrate inside the perimeter. The variable frequency electromagnetic vibration table is activated, causing the substrate and the additive workpiece to vibrate at the same frequency, ensuring that the surface of the flux is level with the surface of the previous layer of additive workpiece. The closed-loop feedback control device also receives the temperature of the additive workpiece measured by an infrared thermometer.

2. The electric arc additive manufacturing system according to claim 1, characterized in that, The robotic additive manufacturing apparatus includes: an additive power supply, an additive robot arm, an additive gun, a wire feeder, a protective gas device, and a control system for controlling the additive motion trajectory of the additive robot arm; The electromagnetic vibration flux conveying device is fixed above the substrate by a tooling fixture. It is adjustable in the X, Y, and Z directions. The amplitude of the electromagnetic vibration flux conveying device is 1.5 mm, the vibration frequency is 3000±100 r / min, and the power is 5~50W. The frequency of the variable frequency electromagnetic vibration table is 1~600HZ, the amplitude is 1~5mm, the load is 80kg, the vibration acceleration is 20g, and it has a built-in PLC adjustment function.

3. A method for additive manufacturing using the electric arc additive manufacturing system according to any one of claims 1-2, characterized in that, Includes the following steps: Step (1): Plan the additive manufacturing path; Step (2): Pre-treatment of the substrate surface, setting up substrate enclosures around the substrate, and assembling the system; Step (3): Start arcing from one end to perform single-layer reciprocating additive manufacturing, and arc additive manufacturing the Nth layer of metal on the substrate, N=1, 2, 3...; Step (4): The closed-loop feedback control device calculates the volume of flux required below the N+1th layer of metal, delivers flux and controls the flux to be poured evenly from below the flux delivery hopper onto the metal substrate inside the enclosure, starts the frequency conversion electromagnetic vibration table, drives the substrate and additive workpiece to vibrate at the same frequency, so that the upper surface of the flux is level with the upper surface of the previous layer of additive workpiece. Step (5): The temperature of the additive workpiece is obtained by using an infrared temperature measuring device. The closed-loop feedback control device receives the temperature of the additive workpiece measured by the infrared temperature measuring device and makes online adjustments. After the workpiece is cooled to the preset temperature, a control command is sent to the robot additive manufacturing platform to perform the N+1 layer of additive manufacturing. Step (6): Repeat steps (3)-(5) until the integrated additively formed part is obtained.

4. The method according to claim 3, characterized in that, The flux used in additive manufacturing consists of spherical particles with a diameter of 1.5~2.5mm, and the melting point of the flux must be 100±10℃ lower than the melting point of the welding wire.

5. The method according to claim 4, characterized in that, The additively formed part is an aluminum alloy part, and the flux is an aluminum-silicon alloy flux particle with one or more of aluminum, silicon, magnesium, sodium, zirconium and potassium added.

6. The method according to claim 4, characterized in that, The additively formed part is a stainless steel part, and the flux is a smelting type low-manganese, high-silicon, medium-fluorine flux granules with added silicon, manganese, aluminum, titanium and vanadium (one or more).

7. The method according to claim 4, characterized in that, The additively formed part is a titanium alloy part, and the flux is a titanium-aluminum type flux particle composed of titanium, aluminum, molybdenum, nickel and chromium.

8. The method according to claim 3, characterized in that, The required flux volume below the Nth metal layer in step (4): V 焊剂 =W×L×H-π×R 2 ×P×T, where W and L are the length and width inside the substrate enclosure, respectively, H is the height of the Nth metal layer in the additive manufacturing process, T is the time for the Nth metal layer in the additive manufacturing process, the wire feeding speed of the wire feeder is P, and the radius of the welding wire is R.

9. The method according to any one of claims 3-8, characterized in that, The shape of additively formed parts is either an additively inclined structural part or a suspended structural part.

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