Aluminum alloy swing laser-vibration-hot wire synergistic efficient material adding method

Abstract

The invention discloses an aluminum alloy swing laser-vibration-hot wire synergistic efficient additive manufacturing method, and belongs to the technical field of laser fuse wire additive manufacturing. The method comprises the steps that an oxidation film and oil stains on the surface of a substrate are removed; starting the swinging laser-vibration-collaborative material adding equipment, adjusting the angles and positions of a laser device and a wire feeding head, and setting material adding parameters; the base plate is fixed, the robot is programmed, a walking route of the additive heat source is set, and the robot is moved to the initial position; a wire heating device is started to preheat the welding wire; an additive heat source and a protective gas switch are turned on, and additive manufacturing is conducted according to the programming track; after a layer of additive wall is completed, surface oxides of the additive wall are cleaned, the programming track of the robot is reset, and after the additive wall is cooled, the next layer of additive is started; and after manufacturing of the additive wall is completed, the swing laser-vibration-hot wire synergistic additive equipment is shut down. The forming precision of the additive wall can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of laser fuse additive manufacturing, and in particular to an aluminum alloy swing laser-vibration-hot wire collaborative high-efficiency additive method. Background Art

[0002] Aluminum alloys have high specific strength, low density, and good corrosion resistance. They are widely used in aerospace, rail transportation, automobile manufacturing, medical equipment and other fields. In response to the requirements of lightweight manufacturing, lightweight material manufacturing technologies represented by aluminum alloys have gradually replaced steel materials. As an emerging forming technology, the current aluminum alloy additive manufacturing technologies at home and abroad mainly include heat source provision methods such as laser, arc, electron beam, ultrasonic wave and stir friction. Lasers have high energy density and low heat input. Compared with arc and electron beam, they have great advantages in high-precision forming. Laser fuse additive manufacturing technology uses laser as a heat source to deposit materials layer by layer by melting welding wire. As a high-energy beam, the energy of laser is concentrated, so the droplet transition process determines the quality of light-wire coupling, and the stability of its deposition process has an important influence on the forming quality of additive parts. In addition, due to the low density and poor fluidity of aluminum alloys, the requirements for wire feeding stability are also high.

[0003] For example, the patent number CN201911171055.8 proposes a laser scanning-vibrating hot wire TIG composite welding method, in which the welding wire reciprocates to generate a vibrating hot wire, and the welding efficiency is improved by preheating the welding wire, but the hot wire vibration accuracy is not high, which is not suitable for additive manufacturing processes with high requirements for forming quality. For example, the patent number CN201811000355.5 proposes a magnetically controlled hot wire swing laser welding device, method and application, which changes the feeding mode of the hot wire by applying an external magnetic field, but is not effectively coupled with the swinging laser, and cannot effectively suppress defects and improve efficiency. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides an aluminum alloy oscillating laser-vibration-hot wire collaborative efficient additive method. In order to improve the forming accuracy of the additive wall, oscillating laser and welding wire vibration are introduced to collaboratively control the molten droplet transition, thereby achieving precise control of the welding wire vibration direction and amplitude. At the same time, the spreading width of the deposited material is controlled by the lateral swing of the wire feeding head.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] An aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method comprises the following steps:

[0007] S1: Remove the oxide film and oil stains on the surface of the aluminum alloy substrate;

[0008] S2: Start the swing laser-vibration-cooperative additive equipment, adjust the angle and position of the laser and the wire feeder, and set the additive parameters, wherein the additive parameters include shielding gas flow, travel speed, wire feed speed, laser power, swing laser frequency, swing laser amplitude, hot wire current, hot wire voltage, and mechanical vibration amplitude and frequency;

[0009] S3: Fix the substrate, program the robot according to the substrate position, set the additive heat source walking route, and move the robot to the initial position;

[0010] S4: starting the hot wire device in the oscillating laser-vibration-synergistic additive device to preheat the welding wire;

[0011] S5: Turn on the additive heat source and protective gas switch, and perform additive according to the programmed trajectory;

[0012] S6: After completing one layer of additive wall, clean the oxide on the surface of the additive wall, reset the robot programming trajectory, wait for the additive wall to cool down, repeat S5, and start the next layer of additive;

[0013] S7: After the manufacturing of the additive wall is completed, the oscillating laser-vibration-hot wire collaborative additive device is turned off.

[0014] Furthermore, the oscillating laser-vibration-hot wire collaborative additive equipment includes a laser and a scanning galvanometer, a galvanometer focusing device, a numerical control system, a hot wire device, a wire feeding device, a vibration device and a water cooler; wherein:

[0015] The laser, scanning galvanometer and galvanometer focusing device are used to generate the oscillating laser beam;

[0016] The CNC system is used to control the welding gun and the oscillating laser travel;

[0017] The hot wire device is used to heat the welding wire;

[0018] The wire feeding device is connected to the welding gun and is used for feeding the welding wire;

[0019] The vibration device is installed on the welding gun to make the welding wire vibrate;

[0020] Water chillers are used for the cooling cycle of additive systems.

[0021] Furthermore, the hot wire device includes a hot wire power supply, the positive and negative electrodes of the hot wire power supply are respectively connected to the wire feeding head and the additive platform, and the welding wire extending out of the wire feeding head generates resistance heat. Before starting the droplet transfer process, the preheating temperature is set by applying current and voltage to the conductive nozzle and the welding wire is preheated below the melting point temperature of the welding wire. The preheating current is controlled at 80-200A, and the preheating voltage is controlled at 6-10V.

[0022] Furthermore, the mechanical vibration and oscillating laser parameters are controlled to jointly control the force input during the droplet transition in the additive process; wherein the force on the droplet during the growth to the fall-off process includes gravity F g , surface tension F γ , plasma flow force F p , electromagnetic force F m , Metal vapor force F rl , laser force F l , mechanical force F2, among which gravity, plasma flow force, electromagnetic force, laser force and mechanical force promote the shedding of molten droplets, while surface tension and metal vapor reaction force hinder the shedding of molten droplets.

[0023] Furthermore, gravity F g , surface tension F γ , plasma flow force F p , electromagnetic force F m , Metal vapor force F rl The expression is as follows:

[0024]

[0025] In the formula, r d is the droplet radius, ρ is the droplet density, and g is the gravitational acceleration;

[0026] F γ =2πr s γk;

[0027] In the formula, r s is the wire radius, γ is the surface tension coefficient, and k is the constant coefficient;

[0028]

[0029] In the formula, C p is the plasma flow coefficient, ρ p is the arc plasma density, K is the proportionality factor, and I is the welding current;

[0030]

[0031] Where μ is the magnetic permeability, θ is the half angle of the arc coverage area, and r s is the wire radius;

[0032]

[0033] In the formula, R h is the metal vapor distribution coefficient, C D is the flow resistance coefficient, A is the vertical flow plane projection area, v0 is a constant, N A is Avogadro's constant, K Bis the Boltzmann constant, T S is the melting temperature of the metal, M α is the molecular mass of the gas, and B is the melt evaporation constant.

[0034] Furthermore, the resultant force F along the wire elongation direction that promotes the droplet to fall off is as follows:

[0035] F=F g cosα+F p +F m +F1′+F2-F γ -F rl cosα;

[0036] Where α is the angle between the wire elongation direction and the vertical direction, and F′1 is the component of the laser force along the wire feeding direction.

[0037] Furthermore, the critical size of droplet shedding is used to measure the amount of filler metal deposition. The mass of metal that drops into the molten pool is given by the following formula:

[0038] m=ρv m πr s 2 =ρv s A;

[0039] In the formula, v m is the wire feeding speed, v s is the walking speed, and A is the cross-sectional area of ​​the sedimentary layer.

[0040] Furthermore, the vibration device includes a vibration power supply, a transverse vibration device and a longitudinal vibration device; the transverse vibration device is connected to the welding gun through a fixing device to drive the wire feeding head to vibrate at high frequency so that the welding wire vibrates at high frequency; the longitudinal vibration device vibrates the wire feeding head along the vibration rod through a buffer spring.

[0041] Furthermore, the angle between the axis of the laser beam and the direction of additive travel is controlled at 80°-85°, the angle between the axis of the laser beam and the axis of the wire feeder is 20°-75°, and the welding wire is located below the laser beam; the laser beam is emitted by a laser.

[0042] Furthermore, the length of the welding wire extending out of the end of the wire feeding head is maintained at 20 mm.

[0043] In summary, compared with the prior art, the above technical solution has the following beneficial effects:

[0044] (1) The hot wire system preheats the welding wire, which effectively reduces the heat input during the additive process and improves the deposition efficiency compared to when the hot wire system is not added. The heat input of the additive process is controlled by adjusting the hot wire power supply and swinging the laser energy, thereby controlling the welding wire melting speed and affecting the droplet transition frequency.

[0045] (2) High-frequency vibration perpendicular to the wire feeding direction (elongation direction) is used to accelerate the droplet shedding and improve the additive efficiency; the swinging laser and mechanical vibration along the wire feeding direction are used to control the droplet shedding position and achieve the position consistency of the droplet transition, thereby ensuring the side wall accuracy of additive forming. It can also control the transition frequency and volume of the minimum mass transfer unit (droplet) in the additive process, achieve high-frequency small particle transition, reduce spatter, and ensure the stability of droplet transition. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of a lateral vibration device according to an embodiment of the present invention;

[0048] Figure 3 It is a schematic diagram of another angle of the lateral vibration device according to an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of a longitudinal vibration device according to an embodiment of the present invention;

[0050] Figure 5 It is a comparison diagram of the oscillating laser-vibration cooperative hot wire and the conventional laser fuse in the embodiment of the present invention.

[0051] Explanation of the reference numerals in the accompanying drawings: 1. substrate; 2. additive wall; 3. swinging laser beam; 4. laser and scanning galvanometer; 5. galvanometer focusing device; 6. numerical control system; 7. hot wire device; 8. wire feeding device; 9. wire feeding head; 10. transverse vibration device; 101. fixing device; 102. fastening screw; 103. transverse vibration motor; 11. longitudinal vibration device; 111. longitudinal vibration motor; 112. buffer spring; 113. vibration rod; 12. fastening device; 13. vibration power supply; 14. welding wire. DETAILED DESCRIPTION

[0052] The principles and features of the present invention are described below in conjunction with all the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0053] The embodiment of the present invention discloses an aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method.

[0054] Commonly used droplet transfer control methods include adjusting the heat source input waveform, applying additional energy fields, etc. The stability of the droplet transfer process affects the spatter generation and additive forming of the additive process. When the wire melting and droplet transfer process are unstable, it will impact the molten pool flow and the stability of the keyhole, causing fluctuations in the molten pool and ultimately affecting production efficiency.

[0055] In the additive process of the embodiment of the present invention, when cold wire is used as the deposition material, a high additive energy input is required, and the deposition efficiency is low. Hot wire is a commonly used optimization method in fuse additive. Currently, the commonly used hot wire methods include arc heating, direct resistance heating and high-frequency induction heating. For laser fuse additive manufacturing technology, direct resistance heating is used. By adjusting the energy input of the hot wire power supply and the energy input ratio of the additive heat source, the total energy input can be accurately controlled, the deposition efficiency is effectively improved, and the bonding performance with the substrate is improved.

[0056] The stability of the droplet transfer process affects the spatter generation and additive forming of the additive process. When the wire melting and droplet transfer process are unstable, it will impact the molten pool flow and the stability of the keyhole, causing the molten pool to fluctuate and ultimately affect production efficiency. Commonly used droplet transfer control methods include adjusting the heat source input waveform and applying additional energy fields.

[0057] In order to improve the forming accuracy of the additive wall, the present invention introduces oscillating laser and welding wire vibration to collaboratively control the molten droplet transfer, thereby achieving precise control of the welding wire vibration direction and amplitude, and at the same time achieving the spreading width control of the deposited material through the lateral swing of the wire feeding head.

[0058] Reference Figure 1-Figure 5 , an aluminum alloy swing laser-vibration-hot wire collaborative efficient material addition method, comprising the following steps:

[0059] S1: removing the oxide film and oil stains on the surface of the aluminum alloy substrate 1;

[0060] S2: Start the swing laser-vibration-cooperative additive device, adjust the angle and position of the laser and the wire feeder 9, and set the additive parameters, wherein the additive parameters include the flow rate of protective gas, the travel speed, the wire feed speed, the laser power, the swing laser frequency, the swing laser amplitude, the hot wire current, the hot wire voltage, and the mechanical vibration amplitude and frequency;

[0061] S3: fix the substrate 1, program the robot according to the position of the substrate 1, set the walking route of the additive heat source, and move the robot to the initial position;

[0062] S4: starting the hot wire device 7 in the oscillating laser-vibration-synergistic additive device to preheat the welding wire 14;

[0063] S5: Turn on the additive heat source and protective gas switch, and perform additive according to the programmed trajectory;

[0064] S6: After completing a layer of additive wall 2, clean the oxide on the surface of the additive wall 2, reset the robot programming trajectory, wait for the additive wall 2 to cool down, repeat S5, and start the next layer of additive;

[0065] S7: After the manufacturing of the additive wall 2 is completed, the swing laser-vibration-hot wire collaborative additive device is turned off.

[0066] The following is an expanded description of each step:

[0067] S1: removing the oxide film and oil stains on the surface of the aluminum alloy substrate 1.

[0068] Specifically, before the test, the surface oxide film of the aluminum alloy substrate 1 was removed by a grinder, and the surface oil stains were removed by ethanol and acetone.

[0069] S2: Start the oscillating laser-vibration-synergistic additive equipment, adjust the angle and position of the laser and the wire feeding head 9, and set the additive parameters, which include shielding gas flow, travel speed, wire feeding speed, laser power, oscillating laser frequency, oscillating laser amplitude, hot wire current, hot wire voltage, and mechanical vibration amplitude and frequency.

[0070] Specifically, the oscillating laser-vibration-hot wire collaborative additive equipment includes a laser and scanning galvanometer 4, a galvanometer focusing device 5, a numerical control system 6, a hot wire device 7, a wire feeding device 8, a vibration device and a water cooler.

[0071] The laser emits a laser beam, the angle between the axis of the laser beam and the direction of the additive travel is controlled at 80°-85°, the angle between the axis of the laser beam and the axis of the wire feeder 9 is 20°-75°, the welding wire 14 is located below the laser beam, and the length of the welding wire 14 extending from the end of the wire feeder 9 is maintained at 20 mm. The power of the laser beam is controlled at 2-4 kW, and the travel speed is controlled at 0.3-3 m / min.

[0072] Among them, the vibration device is a mechanical vibration, including a vibration power supply 13, a transverse vibration device 10 and a longitudinal vibration device 11; the vibration of the transverse vibration device 10 is driven by a transverse vibration motor 103, and the fixing device 101 is fixed to the wire feeding head 9 by a fastening screw 102. The transverse vibration device 10 is connected to the welding gun through the fixing device 101, driving the wire feeding head 9 to vibrate at high frequency, so that the welding wire 14 vibrates at high frequency; the longitudinal vibration device 11 vibrates the wire feeding head 9 along the vibration rod 113 through the buffer spring 112, and the vibration of the vibration rod 113 is driven by the longitudinal vibration motor 111.

[0073] S4: Start the hot wire device 7 in the oscillating laser-vibration-synergistic additive equipment to preheat the welding wire 14.

[0074] Specifically, the diameter of the welding wire 14 is 1.2 mm. The hot wire device 7 includes a hot wire power supply, the positive and negative electrodes of which are respectively connected to the wire feeder 9 and the additive platform, and the welding wire 14 extending out of the wire feeder 9 generates resistance heat. Before the droplet transfer process begins, the preheating temperature is set by applying a current and voltage to the conductive nozzle and the welding wire 14 is preheated below the melting point of the welding wire 14. The preheating current is controlled at 80-200A, and the preheating voltage is controlled at 6-10V.

[0075] S5: Turn on the additive heat source and protective gas switch, and perform additive according to the programmed trajectory.

[0076] Specifically, the shielding gas is released after the shielding gas switch is turned on. The shielding gas is 99.9% argon gas with a gas flow rate of 20-25 L / min. During the material addition process, the transverse vibration device 10 is directly connected to the welding gun through the fixing device 101, driving the wire feeder 9 to vibrate at high frequency, thereby causing the welding wire 14 to vibrate at high frequency. The longitudinal vibration device 11 vibrates the wire feeder 9 along the vibration rod 113 through the buffer spring 112.

[0077] S6: After completing a layer of additive wall 2, clean the oxide on the surface of the additive wall 2, reset the robot programming trajectory, wait for the additive wall 2 to cool down, repeat S5, and start the next layer of additive.

[0078] Specifically, after completing a layer of the additive wall 2, use a wire brush to clean the oxide on the surface of the additive wall 2, and reset the robot programming trajectory. After the additive wall 2 cools down, repeat S5 to start the next layer of additive.

[0079] The hot wire system preheats the welding wire 14, which effectively reduces the heat input during the material addition and improves the deposition efficiency compared to when the hot wire system is not added. The heat input of the material addition process is controlled by adjusting the hot wire power supply and swinging the laser energy, thereby controlling the melting speed of the welding wire 14 and affecting the droplet transition frequency.

[0080] By controlling the mechanical vibration and oscillating laser parameters, the force input during the droplet transition in the additive process can be jointly controlled. The welding wire is heated and melted by the combined heat input of the welding wire preheating and the laser energy input. When the droplet grows to a certain size, it reaches the necking stage under the action of force and begins to fall off. The forces on the droplet during the growth to the fall-off process mainly include: gravity F g , surface tension F γ , plasma flow force F p , electromagnetic force F m , Metal vapor force F rl , laser force F l , mechanical force F2, among which gravity, plasma flow force, electromagnetic force, laser force and mechanical force promote the shedding of molten droplets, while surface tension and metal vapor reaction force hinder the shedding of molten droplets.

[0081] Furthermore, gravity F g , surface tension F γ , plasma flow force F p , electromagnetic force F m , Metal vapor force F rl The expression is as follows:

[0082]

[0083] In the formula, r d is the droplet radius, ρ is the droplet density, and g is the gravitational acceleration;

[0084] F γ =2πr s γk;

[0085] In the formula, r s is the wire radius, γ is the surface tension coefficient, and k is the constant coefficient;

[0086]

[0087] In the formula, C p is the plasma flow coefficient, ρ p is the arc plasma density, K is the proportionality factor, I is the welding current, r d is the droplet radius;

[0088]

[0089] Where μ is the magnetic permeability, θ is the half angle of the arc coverage area, I is the welding current, and r d is the droplet radius, r s is the wire radius;

[0090]

[0091] In the formula, R h is the metal vapor distribution coefficient, C D is the flow resistance coefficient, A is the vertical flow plane projection area, v0 is a constant, N A is Avogadro's constant, K B is the Boltzmann constant, T S is the melting temperature of the metal, M α is the molecular mass of the gas, and B is the melt evaporation constant.

[0092] Furthermore, the resultant force F along the wire elongation direction that promotes the droplet to fall off is as follows:

[0093] F=F g cosα+F p +F m+F1′ + F2 - F γ -F rl cosα;

[0094] Where α is the angle between the wire elongation direction and the vertical direction, and F′1 is the component force of the laser acting force along the wire feeding direction.

[0095] Furthermore, the critical droplet detachment size is used to measure the deposition amount of the filler metal. The mass of the metal that the droplet detaches and enters the molten pool is as follows:

[0096] m = ρv m πr s 2 = ρv s A;

[0097] Where v m is the wire feeding speed, v s is the traveling speed, and A is the cross-sectional area of the deposition layer.

[0098] When the swing laser-vibration-hot wire collaborative additive manufacturing system is not added, during the deposition process, the molten metal at the end of the wire 14 approaches a spherical shape under the action of the resultant force. The droplet will detach from the end of the wire 14 only when it grows to be close to or larger than the size of the end of the wire 14 and then transitions to the molten pool. When the resultant force reaches a value sufficient to cause the droplet to detach from the end of the wire 14, the critical detachment mass of the droplet is m1. At this time, due to the relatively large droplet size, the momentum during the transition to the molten pool is relatively large, and it is easy to cause severe oscillation of the molten pool when entering the molten pool, resulting in serious spatter. And the droplet transition period required for the droplet to reach detachment is long. Therefore, the side wall of the thin-walled wall obtained is rough and the forming is not dense.

[0099] In order to weaken the molten pool oscillation and spatter and control the forming wall surface and forming accuracy, it is necessary to regulate the droplet transition process. After adding the swing laser-vibration-hot wire collaborative additive manufacturing system, during the growth period of the droplet in the additive manufacturing process, the swing laser acts on the molten metal along the swing path. With the increase of heat input and the high-frequency micro-vibration of the wire 14 perpendicular to the wire feeding direction of the wire 14, the droplet gradually grows along the wire elongation direction of the wire 14. When the droplet grows to a certain size and the droplet mass is m2 (m2 < m1), it reaches the necking stage. At this time, due to the phase matching in time of the droplet transition frequency, the swing frequency of the swing laser, and the mechanical vibration frequency along the wire feeding direction of the wire 14, the swing laser just acts on the necking area along the traveling path, and the droplet is subjected to the combined action of the suddenly increased laser acting force and the mechanical vibration force along the wire feeding direction of the wire 14. Compared with the case without the swing laser-vibration-hot wire collaborative additive manufacturing system, the resultant force F along the wire feeding direction of the wire 14 applied to the droplet at this time increases. The resultant force promoting droplet detachment acting on the droplet is greater than the resultant force hindering droplet detachment. At this time, the resultant force F along the wire feeding direction of the wire 14 promotes droplet detachment.

[0100] The droplet shedding control is achieved by matching the droplet transition frequency with the swinging laser and the mechanical vibration frequency along the feeding direction of the welding wire 14. With the addition of the swinging laser and the mechanical vibration of the welding wire 14 along the feeding direction of the welding wire 14, the droplet shedding is accelerated compared to the laser fuse additive process without swinging laser and mechanical vibration. At this time, the swinging laser and mechanical vibration cycle corresponding to a droplet transition cycle are controlled, and the droplet transition frequency is increased, which can realize the high-frequency transition of small particles and effectively avoid the defects of unstable forming process and low forming precision caused by low-frequency transition of large particles. In addition, by controlling the critical size of droplet shedding and the droplet transition frequency, the stability of the droplet transition is increased, so as to control the wall thickness and side wall roughness of the additive wall 2.

[0101] Taking aluminum alloy as an example, the process of additive preparation using the aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency additive method provided above is explained below.

[0102] First, 6061 aluminum alloy was used as the additive substrate. The surface of the substrate with a size of 8 mm thick, 150 mm long, and 75 mm wide was cleaned, the surface oxide film was removed with a grinder, and ethanol and acetone were used to remove oil stains. After cleaning, it was fixed with a clamp.

[0103] Turn on the swing laser-vibration-hot wire collaborative additive equipment, set the experimental parameters as laser power of 3KW, walking speed of 1.0m / min, wire feeding speed of 1.2m / min, laser defocus of 0mm, swing laser mode of circular swing mode, swing laser amplitude of 1mm, longitudinal mechanical vibration amplitude of 2mm, swing laser frequency and longitudinal mechanical vibration frequency of 100Hz. By adjusting the mechanical device of the KUKA robot, the angle between the wire feeding head axis and the swing laser beam axis is adjusted to 25°, the angle between the wire feeding head axis and the horizontal direction is 70°, and the vertical distance between the wire feeding head end and the substrate is 20.5mm.

[0104] The robot is programmed according to the position of the substrate, a linear additive path with a length of 150 mm is set, and the robot is moved to the initial position of the path after the teaching is completed.

[0105] Start the power supply of the hot wire device, adjust the hot wire parameters, and preheat the welding wire. The hot wire current is 150A and the hot wire voltage is 8V. The deposition material is ZL205A aluminum alloy, and the welding wire diameter is 1.2mm.

[0106] Turn on the shielding gas switch, use 99.99% pure argon as shielding gas, and the shielding gas flow rate is 25L / min. At the same time, turn on the swing laser, wire feeding system and vibration device, and add materials according to the programmed trajectory. After walking to the programmed end point, turn off the swing laser, wire feeding system and vibration device at the same time, and turn off the shielding gas.

[0107] After completing one layer of additive wall, use a wire brush to clean the oxide on the surface of the additive wall, raise the robot level according to the layer height, and choose the opposite walking direction of the previous layer, reset the robot programming trajectory. After the additive wall cools down, start the next layer of additive again.

[0108] After the manufacturing of the additive wall is completed, the additive wall is removed and the oscillating laser-vibration-hot wire collaborative additive equipment is turned off.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A highly efficient aluminum alloy additive method using oscillating laser, vibration and hot wire, characterized in that: The following steps are involved: S1: removing the oxide film and oil stains on the surface of the aluminum alloy substrate (1); S2: starting the oscillating laser-vibration-cooperative additive device, adjusting the angle and position of the laser and the wire feeder (9), and setting additive parameters, wherein the additive parameters include shielding gas flow, travel speed, wire feed speed, laser power, oscillating laser frequency, oscillating laser amplitude, hot wire current, hot wire voltage, and mechanical vibration amplitude and frequency; S3: fixing the substrate (1), programming the robot according to the position of the substrate (1), setting the walking route of the additive heat source, and moving the robot to the initial position; S4: starting the hot wire device (7) in the oscillating laser-vibration-synergistic additive device to preheat the welding wire (14); S5: Turn on the additive heat source and protective gas switch, and perform additive according to the programmed trajectory; S6: After completing a layer of additive wall (2), clean the oxide on the surface of the additive wall (2), reset the robot programming trajectory, wait for the additive wall (2) to cool down, repeat S5, and start the next layer of additive; S7: After the manufacturing of the additive wall (2) is completed, the oscillating laser-vibration-hot wire collaborative additive device is turned off.

2. The aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method according to claim 1 is characterized by: The oscillating laser-vibration-hot wire collaborative additive equipment includes a laser and a scanning galvanometer, a galvanometer focusing device, a numerical control system, a hot wire device, a wire feeding device, a vibration device and a water cooler; wherein: The laser, scanning galvanometer and galvanometer focusing device are used to generate the oscillating laser beam; The CNC system is used to control the welding gun and the oscillating laser travel; The hot wire device is used to heat the welding wire; The wire feeding device is connected to the welding gun and is used for feeding the welding wire; The vibration device is installed on the welding gun to make the welding wire vibrate; Water chillers are used for the cooling cycle of additive systems.

3. The aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method according to claim 2 is characterized by: The hot wire device (7) comprises a hot wire power supply, wherein the positive and negative electrodes of the hot wire power supply are respectively connected to the wire feeding head (9) and the material adding platform, and the welding wire (14) extending out of the wire feeding head (9) generates resistance heat. Before the droplet transfer process begins, the preheating temperature is set by applying a current and a voltage to the conductive nozzle, and the welding wire (14) is preheated below the melting point temperature of the welding wire (14), and the preheating current is controlled at 80-200 A, and the preheating voltage is controlled at 6-10 V.

4. The aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method according to claim 3 is characterized by: By controlling the mechanical vibration and oscillating laser parameters, the force input during the droplet transition in the additive process can be jointly controlled; the force on the droplet during the growth and shedding process includes gravity F g , surface tension F γ , plasma flow force F p , electromagnetic force F m , Metal vapor force F rl , laser force F l , mechanical force F2, among which gravity, plasma flow force, electromagnetic force, laser force and mechanical force promote the shedding of molten droplets, while surface tension and metal vapor reaction force hinder the shedding of molten droplets.

5. The aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method according to claim 4 is characterized in that: Gravity F g , surface tension F γ , plasma flow force F p , electromagnetic force F m , Metal vapor force F rl The expression is as follows: In the formula, r d is the droplet radius, ρ is the droplet density, and g is the gravitational acceleration; F γ =2πr s γk; In the formula, r s is the wire radius, γ is the surface tension coefficient, and k is the constant coefficient; In the formula, C p is the plasma flow coefficient, ρ p is the arc plasma density, K is the proportionality factor, and I is the welding current; Where μ is the magnetic permeability, θ is the half angle of the arc coverage area, and r s is the wire radius; ； In the formula, R h is the metal vapor distribution coefficient, C D is the flow resistance coefficient, A is the vertical flow plane projection area, v0 is a constant, N A is Avogadro's constant, K B is the Boltzmann constant, T S is the melting temperature of the metal, M α is the molecular mass of the gas, and B is the melt evaporation constant.

6. The aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method according to claim 5 is characterized by: The resultant force F along the wire elongation direction that promotes the droplet to fall off is as follows: F=F g cosα+F p +F m +F1′+F2-F γ -F rl cosα; Where α is the angle between the wire elongation direction and the vertical direction, and F′1 is the component of the laser force along the wire feeding direction.

7. The aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method according to claim 6 is characterized by: The critical size of droplet shedding is used to measure the amount of filler metal deposition. The mass of metal that drops off into the molten pool is as follows: m=ρv m pr s 2 =ρv s A; In the formula, v m is the wire feeding speed, v s is the walking speed, and A is the cross-sectional area of ​​the sedimentary layer.

8. The aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method according to claim 2 is characterized by: The vibration device comprises a vibration power source (13), a transverse vibration device (10) and a longitudinal vibration device (11); the transverse vibration device (10) is connected to the welding gun via a fixing device (101) to drive the wire feeding head (9) to vibrate at a high frequency, so that the welding wire (14) vibrates at a high frequency; the longitudinal vibration device (11) vibrates the wire feeding head (9) along a vibration rod (113) via a buffer spring (112).

9. The aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method according to claim 1 is characterized by: The angle between the axis of the laser beam and the direction of material addition is controlled at 80-85°, the angle between the axis of the laser beam and the axis of the wire feeder (9) is 20-75°, and the welding wire (14) is located below the laser beam; the laser beam is emitted by a laser.

10. The aluminum alloy oscillating laser-vibration-hot wire collaborative high-efficiency material addition method according to claim 2, characterized in that: The length of the welding wire (14) extending out of the end of the wire feeding head (9) is maintained at 20 mm.

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