A high efficiency electric arc-friction stir processing additive manufacturing system and method

Abstract

The application discloses a kind of high-efficiency electric arc-friction stir processing additive manufacturing system and method, it is related to welding additive manufacturing technical field.Therein, manufacturing system includes control device, friction stir processing device, high-efficiency electric arc device and ultrasonic device, it has unique advantage to the processing of large engineering to be additive sample piece, effectively solve the problem of many blowholes of ordinary electric arc additive manufacturing and avoid the influence that heat input increases and causes performance to be poor.The cost of manufacturing system is low, production line is easy to copy, and can realize the additive manufacturing process of automation, in line with modern industrial production demand.Single system control is used, manufacturing process method is simple, the problem that electric arc additive quality stability is poor, large component additive efficiency is low is solved, and high-quality and high-efficiency additive manufacturing process of large component is realized.

Description

Technical Field

[0001] This invention relates to the field of welding additive manufacturing technology, and more specifically, to a high-efficiency arc-stir friction processing additive manufacturing system and method. Background Technology

[0002] Solid-state additive manufacturing technology has unique advantages in the additive manufacturing of alloy components, but it is still in the laboratory research stage due to the low additive efficiency and the difficulty and poor stability of continuous additive feeding. Porosity is unavoidable in arc additive manufacturing, so pulsed additive manufacturing is often used. The stirring effect of the pulsed arc on the molten pool helps to eliminate porosity and other welding defects. To address porosity during welding / additive manufacturing, the welding / additive speed and the welding / additive heat input are generally used to change the molten pool contact time and reduce the amount of porosity. However, this increases the heat input, which in turn increases welding / additive deformation and internal stress. Therefore, a solution is needed that can improve efficiency while reducing porosity size and avoiding the performance degradation caused by increased heat input.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The present invention aims to provide a high-efficiency arc-stir friction processing additive manufacturing system and method, which can stably control additive manufacturing quality, improve automation level, significantly improve porosity in additive manufacturing, and improve additive manufacturing efficiency and quality.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] In a first aspect, embodiments of the present invention provide a high-efficiency arc-friction stir additive manufacturing system, which includes a control device, a friction stir processing device, a high-efficiency arc device, and an ultrasonic device;

[0007] The control device controls a high-efficiency electric arc device for additive manufacturing; the control device controls a friction stir processing device for friction stir processing.

[0008] The ultrasonic device is positioned between the friction stir processing device and the high-efficiency electric arc device, and is close to the friction stir processing device; the ultrasonic device is movably connected to the friction stir processing device; the control device controls the ultrasonic device to assist in additive manufacturing.

[0009] The relative distance between the high-efficiency electric arc device and the friction stir processing device is ≤200mm.

[0010] In an optional embodiment of the present invention, the high-efficiency arc device is a shunt plasma high-efficiency arc device, which includes a main power supply, an auxiliary power supply, a shunt plasma high-efficiency arc welding torch, a pulse current control mechanism, an additive base plate, and a current sensor; the shunt plasma high-efficiency arc welding torch includes a wire feeder, a water-cooled copper sleeve, an annular plasma electrode, and a shunt plasma additive manufacturing arc system.

[0011] The positive terminal of the main power supply is connected to the wire feeder, and the negative terminal is connected to the sample to be added. The main arc is formed by the shunt plasma additive manufacturing arc system. The positive terminal of the auxiliary power supply is connected to the wire feeder, and the negative terminal is connected to the water-cooled copper sleeve. The bypass arc is formed by connecting the annular plasma electrode and the bypass shunt arc. The bypass arc and the main arc are coupled together to form a composite arc.

[0012] The pulse current control mechanism coordinates the control of the bypass current and the main current. It includes a pulse signal controller and a pulse signal processor. The pulse signal processor detects the main current pulse signal from the current sensor. When the main current is detected to be at the pulse base value, it triggers the pulse signal controller to adjust the bypass current to the pulse base value to ensure the stability of the composite arc during welding. When the main current pulse is detected to be at the peak value, it triggers the pulse signal controller to adjust the bypass current pulse to the peak value to ensure a low workpiece heat input during welding.

[0013] In an optional embodiment of the present invention, the shunt plasma high-efficiency arc welding gun further includes an insulating ceramic sleeve, a conductive nozzle, a protective gas shield, a plasma confinement nozzle, and welding wire.

[0014] In an optional embodiment of the present invention, the control device includes a processing power source and a welding power source; wherein the processing power source is connected to the friction stir processing device, and the welding power source is connected to the high-efficiency electric arc device.

[0015] In an optional embodiment of the present invention, the friction stir processing apparatus includes a detachably connected processing spindle and a processing tool, wherein the processing spindle is connected to a processing power source, and the processing tool contacts the additive material during friction stir processing;

[0016] A fixing fixture is provided on the side of the machining spindle closest to the machining tool.

[0017] In an optional embodiment of the present invention, the ultrasonic device includes a slidably connected ultrasonic probe and a slide rail, wherein the ultrasonic probe contacts the additive material during friction stirring processing.

[0018] The ultrasonic device is movably connected to the fixed fixture on the machining spindle.

[0019] Secondly, embodiments of the present invention provide a method for additive manufacturing using the aforementioned manufacturing system, the method comprising the following steps:

[0020] (1) Grind the surface of the base plate and the additive parts of the sample to be additively manufactured, and tool according to the additive manufacturing requirements;

[0021] (2) Start the ultrasonic device and the high-efficiency electric arc device to realize the ultrasonic-assisted high-efficiency electric arc additive manufacturing process in the initial stage;

[0022] Once the processing tool of the friction stir processing device reaches the designated position, the processing power supply is turned on to simultaneously realize ultrasonic-assisted high-efficiency electric arc additive manufacturing and friction stir processing.

[0023] (3) After completing one layer of additive manufacturing, repeat step (2) to continue additive manufacturing;

[0024] (4) After the additive manufacturing is completed, first turn off the high-efficiency electric arc device, then turn off the friction stir processing device and the ultrasonic device to complete the additive manufacturing of the sample to be added.

[0025] In an optional embodiment of the present invention, the welding wire extension length is 10mm-13mm during the additive manufacturing process, the wire feeding speed is 5m / min-10m / min, the additive speed is 0.3m / min-0.5m / min, the length of each stacked layer is 220mm-5000mm, and the height of the additive workpiece when the stacking is completed is 5mm-450mm.

[0026] In an optional embodiment of the present invention, the rotational speed of the friction stir machining process is 800 rpm-1500 rpm, the travel speed is 0.1 m / min-0.3 m / min, and the pressing depth is 0.5 mm-1.5 mm.

[0027] The diameter of the shoulder of the mixing head of the processing tool is 8mm-12mm, the length of the mixing pin is 1.3mm-2.7mm, and the diameter of the mixing pin is 1.5-2.5mm.

[0028] In an optional embodiment of the present invention, the additive manufacturing method is unidirectional additive manufacturing; argon is used as a protective gas during the additive manufacturing process, and the flow rate of the protective gas is 8L / min-25L / min.

[0029] The beneficial effects of the embodiments of the present invention include:

[0030] The high-efficiency arc-friction stir additive manufacturing system and method provided in this invention employs a high-efficiency arc additive manufacturing device and a main and bypass pulse coordinated control method. This improves additive manufacturing efficiency while reducing the heat input of the sample to be added, achieving a stable and reliable split-flow plasma high-efficiency arc additive manufacturing process. The use of ultrasonic assistance stabilizes the arc additive manufacturing process and improves the quality and efficiency of friction stir processing. This offers unique advantages for processing large-scale engineering samples and is more suitable for industrial production. Furthermore, it effectively solves the problem of numerous pores in ordinary arc additive manufacturing and the insufficient rigidity of robotic friction stir processing, achieving stable control of the additive manufacturing process.

[0031] The manufacturing system provided by this invention has low cost, is easy to replicate on production lines, and can realize an automated additive manufacturing process, which meets the needs of modern industrial production. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A schematic diagram of the structure of a high-efficiency arc-stir friction additive manufacturing system;

[0034] Figure 2 A schematic diagram of a high-efficiency arc device for shunting plasma;

[0035] Figure 3 Schematic diagram of coordinated control of main and bypass current pulse signals;

[0036] Figure 4 This is a microscopic pore structure diagram of the additive manufacturing process in the first embodiment.

[0037] Figure 5 The image shows the microstructure of the pore structure in the first comparative additive manufacturing process.

[0038] Icons: 100 - Manufacturing System; 101 - Control Device; 102 - Machining Power Supply; 103 - Welding Power Supply; 200 - Friction Stir Machining Device; 201 - Machining Spindle; 202 - Machining Tool; 203 - Fixture; 300 - Ultrasonic Device; 301 - Steering Fixture; 302 - Ultrasonic Probe; 303 - Slide Rail; 400 - High-Efficiency Arc Welding Device; 401 - High-Efficiency Plasma Arc Welding Torch; 402 - High-Efficiency Plasma Arc Welding Device; 403 - Additive Prototype; 404 - Base Plate of Prototype to be Added; 405 - Welding wire; 406- Wire feeder; 407- Insulating porcelain sleeve; 408- Conductive nozzle; 409- Water-cooled copper sleeve; 410- Protective gas shield; 411- Plasma confinement nozzle; 412- Ring plasma electrode; 413- Bypass shunt arc; 414- Composite arc; 415- Main arc; 416- Shunt plasma additive manufacturing arc system; 500- Main power supply; 600- Auxiliary power supply; 700- Pulse current control mechanism; 701- Pulse signal processor; 702- Pulse signal controller; 800- Current sensor. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0041] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0043] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0044] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0045] The impact of porosity on welds / additive manufacturing has been reported in many studies. Among them, large porosity is significantly less dense than small porosity and is more likely to affect the strength, toughness, fatigue life, densification, mechanical strength and thermal conductivity of the product. Therefore, the optimization of welding / additive manufacturing processes should be developed in the direction of reducing and eliminating porosity and defects and improving the quality of prototypes.

[0046] Patent CN201921712815.7 describes a hybrid welding system combining arc welding and friction stir processing, which can simultaneously achieve additive manufacturing and machining. However, this patent relies primarily on a robotic arm for additive manufacturing and machining. For larger samples (403) to be added, the system's rigidity cannot guarantee stable machining. Secondly, in the context of high-quality and high-efficiency manufacturing, ordinary arc additive manufacturing struggles to meet efficiency and quality requirements. Finally, during the simultaneous additive manufacturing and machining process, welding defects are not addressed in a timely manner, leading to uncontrollable welding quality during the welding process, affecting post-weld quality, and lacking auxiliary means to ensure the quality of intermediate welding processes.

[0047] The following describes in detail the overall structure, working principle, and technical effects of the device provided by the present invention, as well as the detailed steps, implementation principles, and technical effects of the supporting method, through embodiments and in conjunction with the accompanying drawings.

[0048] First Embodiment

[0049] This invention provides a high-efficiency arc-friction stir additive manufacturing method. A schematic diagram of the high-efficiency arc-friction stir additive manufacturing system 100 used in this method is provided below. Figure 1 The manufacturing system 100 includes a control device 101, a friction stir processing device 200, a high-efficiency electric arc device 400, and an ultrasonic device 300.

[0050] It should be noted that the manufacturing system 100 provided by the present invention is applicable to additive manufacturing of large and small types of additive samples 403, and has particular advantages for additive manufacturing of large additive samples 403.

[0051] Before additive manufacturing, the surface of the 404 stainless steel base plate and the areas to be added need to be sanded, and then tooling should be installed according to additive manufacturing requirements. Sanding is considered a pre-additive manufacturing process; it is not performed during the additive manufacturing process.

[0052] In this embodiment, the additive manufacturing sample 403 uses 2219-T87 aluminum alloy as the substrate, with substrate dimensions of 260mm × 200mm × 10mm, and ER2319 (1.2mm diameter) aluminum alloy welding wire 405 as the raw material. In other embodiments of the present invention, the substrate material, size, and welding wire 405 material can be reasonably adjusted and replaced according to the actual additive manufacturing needs.

[0053] It should be noted that during the production and transportation of welding wire 405 and the substrate, the surfaces may become contaminated with moisture, dust, grease, or other impurities due to humidity and contamination. These impurities can increase the risk of porosity defects and brittle fracture during additive manufacturing and welding. Therefore, after removing the surface oxide scale and contaminants before use, a drying process is necessary to thoroughly remove surface contaminants and ensure the quality of additive manufacturing and welding.

[0054] The control device 101 includes a processing power source 102 and a welding power source 103; wherein, the processing power source 102 is connected to the friction stir processing device 200 and controls it to perform friction stir processing; the welding power source 103 is connected to the high-efficiency electric arc device 400 and controls it to perform additive manufacturing.

[0055] Please refer to Figure 2 The high-efficiency arc device 400 is a shunt plasma high-efficiency arc device 402, which includes a main power supply 500, an auxiliary power supply 600, a shunt plasma high-efficiency arc welding torch 401, a pulse current control mechanism 700, an additive manufacturing base plate, and a current sensor 800; the shunt plasma high-efficiency arc welding torch 401 includes a wire feeder 406, a water-cooled copper sleeve 409, a ring plasma electrode 412, a shunt plasma additive manufacturing arc system 416, and a bypass shunt arc 413.

[0056] It should be noted that a plasma arc is an arc formed by externally confining the free arc column. Plasma welding arcs have higher temperatures and energy densities than conventional arcs, making them a highly efficient arc welding method. At higher currents, it can achieve stable large-droplet transfer and deep penetration. Bypass current shunting is an important process in efficient arc welding. By keeping the main current constant and using bypass current shunting, the welding current to the base material is reduced, the welding heat input is decreased, and welding efficiency is improved.

[0057] The split-flow plasma high-efficiency arc welding torch 401 also includes an insulating ceramic sleeve 407, a conductive nozzle 408, a protective gas cover 410, a plasma confinement nozzle 411, and a welding wire 405.

[0058] The insulating porcelain sleeve 407 protects the electrode, preventing it from being directly burned by the arc and thus extending its service life. The conductive nozzle 408 is a conductive element for the welding arc or plasma, guiding the welding wire 405, maintaining arc stability, and controlling plasma flow. The protective gas shield 410 provides a gaseous medium to the arc space, protecting the arc, electrodes, and workpiece from atmospheric corrosion. The plasma confinement nozzle 411 rapidly cools the high temperatures generated during welding using internally circulating cooling water, preventing it from melting. Simultaneously, the special structural design of the plasma confinement nozzle 411 confines the arc as it passes through, altering its shape and stability.

[0059] The positive terminal of the main power supply 500 is connected to the wire feeder 406, and the negative terminal is connected to the sample to be added 403. The main arc 415 is formed by the shunt plasma additive manufacturing arc system 416. The positive terminal of the auxiliary power supply 600 is connected to the wire feeder 406, and the negative terminal is connected to the water-cooled copper sleeve 409. The bypass arc is formed by connecting the annular plasma electrode 412 and the bypass shunt arc 413. The bypass arc and the main arc 415 are coupled together to form a composite arc 414.

[0060] It should be noted that the pulse current frequency is controlled during additive manufacturing to complete a stable additive manufacturing process. During additive manufacturing, the shunt plasma additive manufacturing arc system 416 uses the bypass shunt arc 413 to complete the shunt function, reducing the current acting on the workpiece. At the same time, it is coupled with the main arc 415 to form a composite arc 414, completing a high-efficiency additive manufacturing process with low heat input.

[0061] The pulse frequency is much smaller than the ultrasonic frequency, typically between 20Hz and 100Hz. The ultrasonic frequency of the equipment used is 15kHz-40kHz, which can achieve automatic frequency tracking, that is, adjust the frequency according to the pressure of the machining tool holder. The amplitude of the ultrasonic equipment is infinitely adjustable from 2μm to 20μm. The synergistic mechanism is that the pulse coordination achieves a stable arc additive process. After the ultrasonic is applied, the ultrasonic mainly acts on the friction stir machining area, while also having a beneficial effect on the arc additive machining area.

[0062] The pulse current control mechanism 700 coordinates the control of the bypass current and the main current. It includes a pulse signal controller 702 and a pulse signal processor 701. The pulse signal processor 701 detects the main current pulse signal from the current sensor 800. When the main current is detected to be at the pulse base value, it triggers the pulse signal controller 702 to adjust the bypass current to the pulse base value, ensuring the stability of the composite arc 414 during welding. When the main current pulse is detected to be at its peak value, it triggers the pulse signal controller 702 to adjust the bypass current pulse to its peak value, ensuring a low workpiece heat input during welding. A schematic diagram of the coordinated control of the main and bypass current pulse signals is shown below. Figure 3 .

[0063] It should be noted that this embodiment employs a shunt high-efficiency arc additive manufacturing device, with pulse-coordinated control of the high-efficiency arc to achieve stable quality control during the additive manufacturing process. When the main circuit current is at the pulse peak value, the bypass current is also at the pulse peak value. This ensures the most significant reduction in current for the workpiece, reducing heat input to the workpiece, thereby reducing welding deformation and internal stress, expanding the welding process window, and improving welding quality. When the main circuit current is at the pulse base value, the bypass current is also at the pulse base value. This effectively stabilizes the arc, ensuring welding stability.

[0064] For example, in the high-efficiency arc aluminum alloy additive manufacturing process, the main circuit current is 80A-180A, and the bypass current is 20A-80A. The current, voltage, and wire feed speed are positively correlated, and the high efficiency is evident before the bypass current is applied. If the arc additive manufacturing process can be achieved at 140A, after applying the bypass current, the main circuit current can be set to 180A and the bypass current to 40A. At this time, the additive manufacturing current is still 140A, but after the main circuit current increases, the wire feed speed is faster, the amount of deposited metal per unit time increases, and while maintaining consistent forming, the welding speed increases, thus improving the additive manufacturing efficiency.

[0065] Furthermore, in this embodiment, the relative distance between the high-efficiency electric arc device 400 and the friction stir processing device 200 is set to ≤200mm. This is mainly to consider the intensity of the improvement effect of the electric arc additive manufacturing when the same ultrasonic energy field is applied to the middle position of the additive manufacturing workpiece. The ultrasonic effect mainly improves the processing. Beyond a certain range, the effect of the ultrasonic applied to the electric arc molten pool will weaken, and the improvement effect on the electric arc additive manufacturing will be small.

[0066] In this embodiment, the relative distance between the high-efficiency electric arc device 400 and the friction stir processing device 200 is set to 150 mm. In other embodiments of the present invention, the relative distance can be reasonably adjusted according to actual needs.

[0067] At the start of additive manufacturing, the control device 101 controls the ultrasonic device 300 and the shunt plasma high-efficiency arc welding torch 401 to complete the high-efficiency arc additive manufacturing process. The control pulse current control system and the ultrasonic device 300 are coordinated to complete a stable ultrasonic-assisted high-efficiency additive process, and the microstructure during and after additive manufacturing is regulated to initially improve the welding porosity problem.

[0068] It should be noted that during high-efficiency arc additive manufacturing, adjusting the pulse frequency enhances the pulse stirring effect, initially promoting the removal of pores and improving porosity issues. Simultaneously, the ultrasonic effect improves metal wettability and solidification, thus improving weld microstructure. Following high-efficiency arc additive manufacturing, ultrasonic-assisted friction stirring further improves the internal porosity and microstructure of the post-arc additive manufacturing, transforming coarse dendritic crystals into fine equiaxed crystals, increasing density, breaking down and removing pores, reducing pore diameter, applying additive compressive stress, improving the stress state of the additive parts, and enhancing additive performance.

[0069] In this embodiment, the pulse frequency is first adjusted to complete the stable additive manufacturing process during the high-efficiency arc additive manufacturing process, and then the ultrasonic frequency is adjusted to ensure that the two do not cancel each other out, thus guaranteeing the beneficial effects of ultrasonic frequency and pulse additive manufacturing.

[0070] In this embodiment, argon is used as a protective gas during the additive manufacturing process, with a protective gas flow rate of 25 L / min.

[0071] When performing additive manufacturing, a unidirectional additive manufacturing method is selected, with 405 welding wire having a dry extension of 12mm, a wire feeding speed of 8m / min, a stacking layer length of 240mm, an additive workpiece height of 45mm when stacking is completed, and an additive manufacturing speed of 0.35m / min for composite additive manufacturing.

[0072] When additive manufacturing is completed, the high-efficiency electric arc device 400 is turned off first, followed by the friction stir processing device 200 and the ultrasonic control device 101, thus completing the additive manufacturing process of the sample 403 to be added.

[0073] The ultrasonic device 300 includes a slidably connected ultrasonic probe 302 and a slide rail 303, wherein the ultrasonic probe 302 contacts the additive material during friction stir processing; the ultrasonic device 300 is movably connected to the fixed fixture 203 on the machining spindle 201.

[0074] Specifically, the ultrasonic probe 302 is fixedly connected to the ultrasonic device 300 via a slide rail 303. The ultrasonic device 300 is fixedly connected to the rigid fixing fixture 203 on the machining spindle 201 via a steering jig 301. Additive manufacturing is performed on the substrate 404 of the sample to be added, completing the high-quality manufacturing process of the additive component. In this embodiment, the fixing method of the steering jig 301 and the fixing fixture 203 is not particularly limited, and can be reasonably selected according to actual needs.

[0075] An ultrasonic device 300 is positioned between and close to the friction stir processing apparatus 200 and the high-efficiency electric arc apparatus 400 to assist additive manufacturing. The ultrasonic device 300 is activated at the start of the high-efficiency electric arc additive manufacturing process and deactivated at the end of the friction stir process, operating throughout the entire additive manufacturing process, and its frequency is controllable. After the application of ultrasonic waves, the friction stir process is completed under the dual effects of acoustic softening and flow promotion.

[0076] It should be noted that by using the control device 101 to turn on the ultrasonic device 300 and the high-efficiency electric arc device 400, the ultrasonic-assisted high-efficiency electric arc additive manufacturing process is realized in the initial stage.

[0077] By employing ultrasonic assistance, the quality and efficiency of friction stir machining are improved while stabilizing the electric arc additive manufacturing process, making it more suitable for industrial production. Specifically, the placement angles of the ultrasonic device 300 and the friction stir machining device 200, as well as the specific position of the ultrasonic probe 302, are reasonably adjusted according to actual needs using the steering fixture 301 to ensure that the ultrasonic probe 302 contacts the additive material during friction stir machining.

[0078] It should be noted that ultrasound, as a mechanical wave, firstly produces a mechanical effect on the arc welding melt. The stirring of the molten pool helps to expel pores, improves the wettability of the molten pool, and enhances the quality of the additive manufacturing process. Additionally, a portion of the ultrasonic energy is converted into heat energy and absorbed by the melt, improving solidification and forming during the additive manufacturing process, refining the microstructure, and improving performance. Ultrasonic action also helps to remove gas and impurities, making it easier for pores in the molten pool to merge, grow, and be expelled. Regarding the additive microstructure, coarse dendritic crystals are generated during high-efficiency arc additive manufacturing. Under ultrasonic action, some of these coarse dendritic crystals will transform into smaller, non-dendritic crystal structures. During friction stir processing, due to dynamic recrystallization, they will transform into equiaxed crystal structures. The inventors' research also found that the smaller the initial grain size, the smaller the fine equiaxed crystal size formed after friction stir processing, and the higher the hardness. Therefore, the additive sample 403 manufactured using the ultrasonic device 300 assisted by the friction stir processing device 200 exhibits better density and higher performance. The application of ultrasound primarily affects the friction stir process, but it provides initial improvement for the high-efficiency electric arc additive manufacturing process.

[0079] In this embodiment, the ultrasonic device 300 is connected to the friction stir processing device 200, which has the following characteristics:

[0080] (1) Ultrasonic friction reduction effect: Ultrasonic vibration improves the fluidity of the material and reduces the frictional shear stress between the stirring head and the surface of the additive sample 403, thus playing the role of ultrasonic friction reduction; acoustic stress promotes dislocation movement and reduces the plastic shear force at the interface, thus playing the role of ultrasonic softening.

[0081] (2) The ultrasonic softening mechanism specifically refers to the reduction of rheological stress in metals after applying an ultrasonic energy field during friction stir machining. The acoustic energy is preferentially absorbed through lattice defects, reducing shear stress and significantly softening the metal material without requiring significant heating. For 2xxx series aluminum alloys, the inventors found that the ultrasonic energy field can reduce axial pressure by 4%-7% and spindle torque by 4%-8%, with the effect being more pronounced at lower heat inputs. This is clearly more in line with the efficient and low-heat additive manufacturing process, avoiding high-pressure, high-torque, high-power processing, reducing energy consumption during friction stir machining, and conforming to the green, economical, and sustainable industrial development concept.

[0082] The reduced welding pressure of friction stir processing can decrease the surface roughness of the 403 additive manufacturing sample, improve weld formation, and provide a welding process window. For aluminum alloys, applying ultrasound can increase processing speed and efficiency. For example, with 7N01-T4 aluminum alloy, defects such as tunnels and "S"-shaped defects appear at a processing speed of 200 mm / min before the ultrasonic energy field is applied; after applying the ultrasonic energy field, the processing speed can be increased to 300 mm / min without defects, thus expanding the process window and improving processing efficiency.

[0083] (3) Ultrasonic delay effect: After the stirring head completes the stirring of the weld metal, the ultrasonic action still promotes dislocation movement without causing new dislocation proliferation, thereby accelerating grain growth, i.e., ultrasonic delay effect. Under ultrasonic action, the grain size in the stirring zone increases, and the ratio of large and small angle grain boundaries becomes bipolar, which is attributed to the superposition effect of the ultrasonic energy field delay effect and the effect of promoting recrystallization.

[0084] The friction stir processing apparatus 200 includes a detachably connected processing spindle 201 and a processing tool 202. The processing spindle 201 is connected to the processing power supply 102, and the processing tool 202 contacts the additive during friction stir processing. A fixing fixture 203 is provided on the side of the processing spindle 201 near the processing tool 202. The fixing fixture 203 is movably connected to the ultrasonic device 300.

[0085] In this embodiment, a gantry-type friction stir processing device 200 is used. In other embodiments of the present invention, other specifications and brands of friction stir processing devices 200 can be selected according to actual needs.

[0086] It should be noted that the fixing fixture 203 is made of rigid material and is fixedly connected to the machining spindle 201. This prevents the ultrasonic probe 302 or slide rail 303 from falling off due to excessive frequency during operation of the ultrasonic device 300, which would affect the final additive manufacturing quality, additive manufacturing efficiency, material waste, and increased cost. In this embodiment, the fixing method of the fixing fixture 203 on the machining spindle 201 is not particularly limited; it can be reasonably selected according to actual needs, such as threaded connection or welded connection.

[0087] The processing tool 202 includes a stirring head and a stirring needle. In this embodiment, the shoulder diameter of the stirring head is 10 mm, the length of the stirring needle is 2.0 mm, and the diameter of the stirring needle is 2.0 mm. In other embodiments of the present invention, the relevant dimensions of the processing tool 202 can be reasonably adjusted according to the actual additive manufacturing dimensions.

[0088] The rotational speed of the friction stir processing is 1200 rpm, the travel speed is 0.2 m / min, and the pressing depth is 1.0 mm; these are related to the specifications of the 403 sample to be added and the thickness of each layer of additive manufacturing; in other embodiments of the present invention, reasonable adjustments can be made according to actual needs.

[0089] After the machining tool 202 reaches the machining position, the control device 101 controls the machining power supply 102 to work, and the friction stir machining tool 202 starts to perform the machining task. The distance between the ultrasonic probe 302 and the friction stir machining tool 202 is adjusted by the slide rail 303. After the ultrasonic action is applied, the friction stir machining process is completed under the dual effects of sono-softening and flow promotion, and efficient electric arc additive manufacturing and friction stir machining are realized simultaneously.

[0090] The microstructure of the additive manufacturing process in this embodiment is shown in the image. Figure 4 ,from Figure 4 As can be seen, the pores on the additive surface are evenly distributed and their size is significantly reduced. This invention method can reduce the cost of aluminum alloy arc additive manufacturing system 100, improve additive manufacturing quality, and is suitable for additive manufacturing processes of large components.

[0091] Please refer to Figure 1 and Figure 2 The specific process of additive manufacturing using the ultrasonic-assisted high-efficiency arc-stir friction processing additive manufacturing system 100 in this embodiment is as follows:

[0092] (1) ER2319 (1.2mm diameter) aluminum alloy welding wire 405 is used as raw material, and 2219-T87 aluminum alloy is used as substrate. The substrate size is 260mm×200mm×10mm.

[0093] It should be noted that the 405 welding wire and the substrate were dried after removing the surface oxide scale and contaminants before use; argon was used as the protective gas during the test, and the protective gas flow rate was 25L / min.

[0094] (2) At the start of additive manufacturing, the control device 101 controls the ultrasonic device 300 and the shunt plasma high-efficiency arc welding torch 401 to complete the high-efficiency arc additive manufacturing process, and coordinates the control. Figure 2 Medium pulse current control mechanism 700 and Figure 1 The ultrasonic device 300 completes a stable ultrasonic-assisted high-efficiency additive manufacturing process, regulates the microstructure during and after additive manufacturing, and initially improves the welding porosity problem.

[0095] After the processing tool 202 in the friction stir processing device 200 reaches the processing position, the control device 101 controls the processing power supply 102 to work, and the processing tool 202 begins to perform the processing task. The relative distance between the ultrasonic probe 302 and the processing tool 202 is adjusted to 50mm by the slide rail 303. After the ultrasonic action is applied, the friction stir processing step is completed under the dual action of acoustic softening and promoting flow.

[0096] It should be noted that when performing composite additive manufacturing, the unidirectional additive method is selected, and the specific process parameters are as follows: 405 welding wire with a dry extension of 12mm, wire feeding speed of 8m / min, additive speed of 0.35m / min, length of each stacked layer of 240mm, and height of the additive workpiece after stacking of 45mm.

[0097] The stirring head has a shoulder diameter of 10mm, a stirring pin length of 2.0mm, and a stirring pin diameter of 2.0mm. The rotational speed of the stirring friction process is 1200rpm, the travel speed is 0.2m / min, and the pressing depth is 1.0mm.

[0098] It should be noted that the additive manufacturing in this embodiment is completed under the combined effect of ultrasonic-assisted high-efficiency electric arc-friction stir composite additive manufacturing.

[0099] (3) After the shunt plasma high-efficiency arc welding gun 401 completes the arc additive manufacturing process of this layer, the control device 101 controls the welding power supply 103 to be turned off. After the processing tool 202 completes the processing task of this layer, it is raised again according to the lifting procedure. Step (2) is repeated. This cycle is repeated to complete the ultrasonic-assisted high-efficiency arc-stir friction processing composite additive manufacturing.

[0100] (4) After the additive manufacturing is completed, first turn off the high-efficiency electric arc device, then turn off the friction stir processing device and the ultrasonic device to complete the additive manufacturing of the sample to be added.

[0101] First comparison

[0102] This comparative example provides a high-efficiency arc-friction stir additive manufacturing system 100. The only difference between this system and the first embodiment is that the ultrasonic device 300 is turned off during the additive manufacturing process, and ultrasonic-assisted additive manufacturing is not provided. The microstructure of the additively manufactured pores is shown in the figure. Figure 5 ,from Figure 5 It can be seen that the pores on the additive surface are large and unevenly distributed.

[0103] In summary, the high-efficiency arc-stir friction additive manufacturing system 100 and method provided by the present invention have the following characteristics:

[0104] (1) The manufacturing method provided in the embodiments of the present invention includes high-efficiency electric arc additive manufacturing, ultrasonic pulse coordinated control and high rigidity stirring friction processing. The manufacturing method has a simple process and single system control, which solves the problems of poor quality stability of electric arc additive manufacturing and low additive efficiency of large components, and realizes a high-quality and high-efficiency additive manufacturing process for large components.

[0105] (2) The present invention adopts an ultrasonic-assisted method, which improves the quality and efficiency of friction stir processing while stabilizing the electric arc additive manufacturing process, making it more suitable for process production.

[0106] (3) The shunt high-efficiency electric arc additive manufacturing device used in the embodiments of the present invention can reduce the heat input of the parent material while improving the additive manufacturing efficiency. At the same time, the pulse coordination control method has specific advantages for the additive manufacturing of lightweight alloys.

[0107] (4) The pulse coordination control proposed in this invention can be used in combination with ultrasonic-assisted control. Through the coordinated control of the two, the intermediate process control of additive manufacturing can be realized.

[0108] (5) This invention effectively solves the problem of numerous pores in conventional electric arc additive manufacturing, and at the same time solves the problem of insufficient rigidity in robot friction stir processing. It combines the traditional gantry-type friction stir processing device 200 with the newly invented shunt high-efficiency electric arc welding, giving full play to the advantages of each process and achieving stable control of the additive manufacturing process.

[0109] (6) The manufacturing system 100 proposed in this invention has low cost and can realize an automated additive manufacturing process, which meets the needs of modern industrial production.

[0110] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-efficiency arc-stir friction additive manufacturing system, characterized in that, The manufacturing system includes a control device, a friction stir processing device, a high-efficiency electric arc device, and an ultrasonic device; The control device controls the high-efficiency electric arc device to perform additive manufacturing; the control device controls the friction stir processing device to perform friction stir processing; The ultrasonic device is disposed between the friction stir processing device and the high-efficiency electric arc device, and is close to the friction stir processing device; the ultrasonic device is movably connected to the friction stir processing device; the control device controls the ultrasonic device to assist in additive manufacturing. The friction stir machining device includes a detachably connected machining spindle and machining tools; The ultrasonic device includes a slidably connected ultrasonic probe and a slide rail, wherein the ultrasonic probe contacts the additive material during friction stir machining; the ultrasonic device is movably connected to a fixed fixture on the machining spindle. The relative distance between the high-efficiency electric arc device and the friction stir processing device is ≤200mm.

2. The manufacturing system according to claim 1, characterized in that, The high-efficiency arc device is a shunt plasma high-efficiency arc device, which includes a main power supply, an auxiliary power supply, a shunt plasma high-efficiency arc welding torch, a pulse current control mechanism, an additive base plate, and a current sensor; the shunt plasma high-efficiency arc welding torch includes a wire feeder, a water-cooled copper sleeve, a ring plasma electrode, and a shunt plasma additive manufacturing arc system. The positive terminal of the main power supply is connected to the wire feeder, and the negative terminal is connected to the sample to be added. The main arc is formed through the shunt plasma additive manufacturing arc system. The positive terminal of the auxiliary power supply is connected to the wire feeder, and the negative terminal is connected to the water-cooled copper sleeve. The bypass arc is formed by connecting the annular plasma electrode and the bypass shunt arc. The bypass arc and the main arc are coupled together to form a composite arc; The pulse current control mechanism coordinates the control of the bypass current and the main current, and includes a pulse signal controller and a pulse signal processor. The pulse signal processor detects the main current pulse signal of the current sensor. When the main current is detected to be at the pulse base value, it triggers the pulse signal controller to adjust the bypass current to the pulse base value to ensure the stability of the composite arc during welding. When the main current pulse is detected to be at its peak, the pulse signal controller is triggered to adjust the bypass current pulse to its peak value, ensuring low workpiece heat input during welding.

3. The manufacturing system according to claim 2, characterized in that, The shunt plasma high-efficiency arc welding gun also includes an insulating ceramic sleeve, a conductive nozzle, a protective gas shield, a plasma confinement nozzle, and welding wire.

4. The manufacturing system according to claim 1, characterized in that, The control device includes a processing power source and a welding power source; wherein the processing power source is connected to the friction stir processing device, and the welding power source is connected to the high-efficiency electric arc device.

5. The manufacturing system according to claim 1, characterized in that, The machining spindle is connected to the machining power supply, and the machining tool comes into contact with the additive material during friction stir machining. A fixing fixture is provided on the side of the machining spindle near the machining tool.

6. A method for additive manufacturing using the manufacturing system as described in any one of claims 1-5, characterized in that, The method includes the following steps: (1) Grind the surface of the base plate of the sample to be added and the parts to be added, and tool according to the requirements of additive manufacturing; (2) Start the ultrasonic device and the high-efficiency electric arc device to realize the ultrasonic-assisted high-efficiency electric arc additive manufacturing process in the initial stage; Once the processing tool of the friction stir processing device reaches the designated position, the processing power supply is turned on to simultaneously realize ultrasonic-assisted high-efficiency electric arc additive manufacturing and friction stir processing. The ultrasonic device is activated at the start of high-efficiency arc additive manufacturing and stopped at the end of friction stir processing. (3) After completing one layer of additive manufacturing, repeat step (2) to continue additive manufacturing; (4) After the additive manufacturing is completed, first turn off the high-efficiency electric arc device, then turn off the friction stir processing device and the ultrasonic device to complete the additive manufacturing of the sample to be added.

7. The method according to claim 6, characterized in that, During additive manufacturing, the wire extension is 10 mm-13 mm, the wire feeding speed is 5 m / min-10 m / min, the additive speed is 0.3 m / min-0.5 m / min, the length of each stacked layer is 220 mm-5000 mm, and the height of the additive workpiece after stacking is 5 mm-450 mm.

8. The method according to claim 6, characterized in that, The rotational speed of the friction stir machining process is 800 rpm-1500 rpm, the travel speed is 0.1 m / min-0.3 m / min, and the compressive depth is 0.5 mm-1.5 mm. The stirring head of the processing tool has a shoulder diameter of 8 mm-12 mm, a stirring needle length of 1.3 mm-2.7 mm, and a stirring needle diameter of 1.5-2.5 mm.

9. The method according to claim 6, characterized in that, The additive manufacturing process employs unidirectional additive manufacturing; argon is used as a protective gas during the additive manufacturing process, with a flow rate of 8 L / min-25 L / min.

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