Additive manufacturing apparatus and method for deflecting arrangement of multiple laser stirred melt pools

Abstract

An additive manufacturing apparatus and method with a deflected arrangement of multiple laser-stirred molten pools includes a wire feeding system capable of delivering metal wire to the focal point of the laser beam and the base material; a laser mirror deflected around the wire feeding gun tube for adjusting the laser beam path and delivering the laser beam to the focal point of the metal wire and the base material; and an electrothermal metal wire, with the wire feeding nozzle and the base material respectively connected to external heating power supplies, forming a current loop between the heating power supply, the metal wire, and the base material to generate resistance heating, which assists in preheating and melting the metal wire by the laser light source. This invention combines laser heating and resistance heating to improve heat input and thermal efficiency while ensuring processing accuracy, reducing the temperature difference between the base material and the metal wire, reducing thermal stress, stirring the molten pool, and improving material performance.

Description

Technical Field

[0001] This invention relates to the field of metal wire additive manufacturing technology, specifically to an additive manufacturing equipment and method for preheating, melting, and stirring a molten pool of metal wire using a deflection arrangement with multiple laser-guided resistance heating. Background Technology

[0002] Additive manufacturing technology is an advanced digital manufacturing technology that utilizes the principle of layer-by-layer welding and cladding, employing electric arcs, lasers, electron beams, plasmas, etc., as heat sources. Through the continuous addition of metal wires under program control, metal parts are gradually formed from lines to surfaces to solids based on a three-dimensional digital model. This technology has been applied in aerospace, shipbuilding, military, energy, and in-situ repair fields.

[0003] Laser metal additive manufacturing employs a direct energy deposition (DED) process, which utilizes a distributed laser source to focus multiple laser beams onto a working surface. On this working surface, the laser focus intersects with the metal material (wire or powder) to form a layered metal structure on the base material under computer control.

[0004] Existing laser metal additive manufacturing technologies integrate lasers with multi-axis computer numerical control (CNC) machines. They use a laser beam focused onto metal material through a direct energy deposition (DED) nozzle to process three-dimensional parts. Computer-aided design (CAD) and computer-aided manufacturing (CAM) software are integrated with the DED process to drive the nozzle for precise rendering of the three-dimensional parts. Most existing laser metal additive manufacturing methods involve the laser beam entering through the center of the nozzle, with the metal material introduced through the nozzle via a coaxial or lateral feed mechanism.

[0005] Patent No. CN201980097374.0, Patent Title: Multimode Laser Device for Metal Manufacturing Applications. This technology includes an integrated wire drawing system, multiple off-axis laser sources, a shielding gas delivery system, and a cooling system. The multiple off-axis lasers are used to deliver a laser beam to a focal point at a working surface. The multiple off-axis laser sources include multiple insertable laser assemblies, each including an internal solid-state diode laser with a back-reflection protection element. The back-reflection protection element detects back reflection via a photosensitive sensor and allows for rapid, transient deactivation of the corresponding laser assembly. The integrated wire drawing system has automatic feed pressure control and is capable of delivering a metal wire from a central axis wire feed guide through and into a central deposition nozzle within a deposition housing to the focal point of the wire, powder, and laser. The shielding gas delivery system is capable of delivering shielding gas to the focal point of the wire, powder, and laser.

[0006] Patent No. 201880050023.x, Patent Title: Coaxial Laser Hot Wire Head, the technology includes a first contact point connected to a power source; a second contact point connected to the power source, the power source being configured to generate current to flow through an electrode wire between the first contact point and the second contact point to heat the electrode wire; a laser source, the laser source being configured to generate one or more laser beams having laser power sufficient to at least partially melt the electrode wire; and a coaxial laser head, the coaxial laser head being configured to focus the one or more laser beams at one or more focal points on a workpiece to at least partially melt the electrode wire.

[0007] Patent No. CN201820545818.5, Patent Title: Coaxial Composite Multi-Beam Laser + Electrothermal Wire Deposition Equipment. This technology utilizes multiple lasers, or a single laser after beam splitting, to output multiple laser beams. These beams are sequentially collimated and focused by multiple collimating-focusing lens groups evenly distributed in a circle on a working head, and then converge in front of the working head. A wire feeding mechanism feeds the wire along the centerline of the working head, extending to the surface of the workpiece or substrate. A heating power supply, the wire, the workpiece, and the substrate form a current loop. When energized, resistance heat is generated in the wire, forming a coaxial composite energy field with the converged multi-beam focused laser. Under computer control, this composite energy field heats and melts the continuously fed wire, depositing it to form the desired shape. Each collimating lens and a focusing lens in the working head form a parallel lens group with a common central axis. The central axes of multiple lens groups are evenly distributed on the same rotating conical surface with the wire's centerline as the axis. The shape of the laser spot on the workpiece or substrate surface after convergence varies with the angle between the rotating conical surface and its central axis.

[0008] Technical problems existing in the current technology.

[0009] (1) Simple resistance heating wire feeding additive manufacturing cannot solve the problem of poor fusion between welds of metal wires, resulting in gaps between welds during the additive manufacturing process, lack of fusion, and anisotropy of the material, such as Figure 15 As shown.

[0010] (2) Main problems of laser additive manufacturing: The molten pool produced by laser additive manufacturing is relatively stable, thus having the advantage of high cladding precision. However, the laser power generated by a single laser and the absorption efficiency of the material to the laser are limited. If only the laser is used as a single heat source, the power required for the molten wire will be greatly increased, and the manufacturing cost of the equipment will also be greatly increased. Therefore, other forms of heat input can be used as a composite heat source to improve the heat input efficiency (these other forms of heat input have the characteristics of high heating electrothermal efficiency). This can both give full play to the high precision of the laser and improve the cladding deposition efficiency. For example, the electro-optic efficiency of semiconductor lasers is about 50%, the absorption efficiency of steel at a wavelength of 976nm is between 20% and 50%, and the thermal efficiency of resistance heating is as high as about 90%. Therefore, using a composite heat source wire of electrode resistance and laser can both give full play to the high precision of the laser and improve the cladding deposition efficiency.

[0011] (3) The technical problems exist that multiple laser beams and metal wires are in the same plane and coaxial.

[0012] When the laser beam and the metal wire are on the same plane, under high laser power, the reflected laser light from the laser beam irradiating the base material will directly melt the metal wire, forming spherical metal droplets, thus affecting the continuity of the cladding trajectory. The metal droplets will not drip due to surface tension, and their size will block the laser beam, preventing it from directly irradiating the base material, thus hindering the formation of a good molten pool. Furthermore, the increasing heat input from the direct laser beam causes the droplets to grow larger as the metal wire is fed, damaging the welding torch nozzle. Figure 16 and 17 As shown. Summary of the Invention

[0013] To address the aforementioned technical problems, this invention proposes a multi-laser additive manufacturing equipment and method that uses a deflected arrangement of multiple laser-guided resistance heating preheating, melting of metal wire, and stirring of the molten pool. Specifically, the laser mirrors are deflected so that their axes are out of plane with the axis of the wire feed gun. The laser mirrors guide the laser beam path to be incident on the base material at a certain angle deviating from the axes of the wire feed gun and the metal wire, thus avoiding the formation of spherical metal droplets. Simultaneously, the molten pool is stirred through laser beam pressure and periodic changes in laser power, which helps to prevent anisotropy in the metal structure. Furthermore, a heating power source is connected between the metal wire and the base material, forming a current loop and generating resistance heating. The deflected laser-guided resistance heating preheating, melting of the metal wire, and stirring of the molten pool can refine the grains and improve the various properties of the additively manufactured parts.

[0014] Additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools, including

[0015] A wire feeding system, which is driven by a drive mechanism, is able to transmit metal wire through the wire feeding gun barrel and the wire feeding conductive nozzle to the focal point of the laser spot and the base material;

[0016] b. A laser mirror is deflected around the wire feeding gun barrel. The laser mirror is used to adjust the laser beam path and deliver the laser beam to the focal point between the metal wire and the base material. The deflection arrangement means that the axis of the laser mirror is not coplanar with the axis of the wire feeding gun barrel. The laser source is multiple laser beams divided from a single laser beam, or is composed of no less than two lasers.

[0017] c. The electric heating metal wire is connected to an external heating power source, and the wire feeding conductive nozzle and the base material are respectively connected to a heating power source. A current loop is formed between the heating power source, the metal wire and the base material. When the power is applied, the metal wire generates resistance heat, which in turn preheats and assists the laser light source in melting the metal wire.

[0018] d. Cooling system, which is used to cool the wire feed gun barrel and the laser mirror;

[0019] e. Protective gas system, the protective gas system being used to deliver protective gas to the focal point of the metal wire, the laser spot and the base material;

[0020] It can adjust the laser path by deflecting the laser mirror arranged around the wire feeding gun barrel (b), and use the electrothermal metal wire (c) to assist in preheating the laser source, melting the metal wire, and stirring the molten pool for additive manufacturing.

[0021] Furthermore, the laser light spot incident on the substrate is non-circular, and the axis of the non-circular light spot is not coplanar with the axis of the wire feeding gun tube, and the optical path of the laser light source deviates from the axis of the wire feeding gun tube.

[0022] Furthermore, the light spot can be elliptical, annular, crescent-shaped, triangular, rectangular, or square.

[0023] Furthermore, when the laser source consists of at least two lasers, the power of each laser exhibits a periodic variation. Within a period, the power of each laser increases or decreases sequentially according to the clockwise or counterclockwise deflection arrangement of the laser mirrors. When a molten pool is formed on the base material, the laser pressure component along the laser spot plane exerts a pushing or dragging force on the molten pool, thereby propelling or dragging the molten pool and stirring it. When the laser mirrors consist of an even number of laser mirrors (at least two), such as six, the laser mirrors can be arranged in a staggered clockwise or counterclockwise deflection arrangement, with adjacent laser mirrors being symmetrical. When there is an even number of laser mirrors, the staggered clockwise or counterclockwise deflection arrangement can effectively reduce the thermal damage to the laser mirrors at symmetrical positions caused by laser reflection.

[0024] Furthermore, the power variation period of each laser is 1Hz-20000Hz, and the power variation range is 0w-6000w.

[0025] Furthermore, the number of laser mirrors is six, and the power variation period of each laser is 1Hz-1000Hz, with a power variation range of 0W-200W.

[0026] Furthermore, the laser mirror is provided with a laser interface, a collimating lens, a focusing lens, and a protective lens arranged from top to bottom, or the laser interface, a focusing lens, and a protective lens arranged from top to bottom.

[0027] Furthermore, the collimating lens and focusing lens can be adjusted in position via an adjustment mechanism, thereby adjusting the focal length and focus of the laser mirror.

[0028] Furthermore, the laser is one or more of the following combinations: an externally fiber-coupled solid-state diode laser, an externally fiber-coupled diode-pumped solid-state laser, an internally fiber-coupled solid-state diode laser, and an internally fiberless solid-state diode laser.

[0029] Furthermore, the laser mirror axis has an angle of 10-80 degrees with the wire feed gun tube axis and an angle of 10-80 degrees with the base material.

[0030] Furthermore, the laser mirror axis is at a 30-degree angle to the wire feed gun tube axis and at a 60-degree angle to the base material.

[0031] Furthermore, the number of lasers is 2-16, with an equal number of laser mirrors corresponding to each laser.

[0032] Furthermore, the number of lasers is 3, 5, or 6.

[0033] Furthermore, the wire feeding system includes an active wire feeding wheel and a driven wire feeding wheel, which press the metal wire and continuously transfer the metal wire to the focal point of the laser spot and the base material.

[0034] Furthermore, the wire feeding system also includes an active wire feeding gear and a driven wire feeding gear. The active wire feeding gear is driven by a drive motor and is connected to the driven wire feeding gear. The driven wire feeding gear is fixedly connected to the active wire feeding wheel. The active wire feeding gear and the driven wire feeding gear drive the active wire feeding wheel and the driven wire feeding wheel. The active wire feeding wheel and the driven wire feeding wheel press the metal wire and continuously transfer the metal wire to the focal point of the laser spot and the base material.

[0035] Furthermore, the wire feeding system also includes a wire feeding wheel clamping mechanism, which is connected to one of the active or driven wire feeding wheels via a fixed block, and achieves bidirectional clamping of the active and driven wire feeding wheels through linkage with the fixed block.

[0036] Furthermore, the wire feeding wheel clamping mechanism is equipped with an elastic mechanism inside, which is connected to the telescopic mechanism, and the telescopic mechanism can slide left and right.

[0037] Furthermore, the elastic mechanism is a spring, and the telescopic mechanism is a threaded screw and a nut. The spring is sleeved on the screw, and the screw and nut are fixedly connected. The spring applies force to the nut and the screw, and the change in the magnitude of the spring force forces the nut and the screw to slide left and right. Then, through the linkage of the connected fixed block, the bidirectional clamping of the active wire feeding wheel and the driven wire feeding wheel is realized.

[0038] Furthermore, the cooling system includes a laser mirror cooling system and a wire feed gun barrel cooling system, and the cooling system is water-cooled.

[0039] An additive manufacturing method using an additive manufacturing system with a deflected arrangement of multiple laser stirring molten pools includes the following steps:

[0040] a. Heating metal wire: Turn on the heating power supply connecting the wire feeding nozzle and the base material, and a current loop is formed between the heating power supply, the metal wire and the base material to generate resistance heat to preheat the metal wire and the base material;

[0041] b. Laser-guided resistance thermomelting of metal wire: The laser mirror, which is deflected and arranged in the wire feeding gun tube, adjusts the laser beam path to be incident on the focal point of the metal wire and the base material. The laser beam path is deviated from the metal wire, and the laser spot axis is not coplanar with the metal wire. The laser-guided resistance heat preheats and melts the metal wire.

[0042] c. The effect of laser light pressure and the periodic variation of laser light on stirring the molten pool: The power of each laser exhibits periodic variation. The power of each laser increases or decreases sequentially at different time periods within a cycle according to the clockwise or counterclockwise deflection of the laser mirrors. When a molten pool is formed on the base material, the laser light pressure component along the laser spot plane generates a pushing or dragging force on the molten pool. Under the action of the periodic variation of laser power, the energy flow together pushes or drags the molten pool, thereby stirring the molten pool.

[0043] Furthermore, the metal wire can be preheated by an external induction coil.

[0044] The beneficial technical effects of this invention are as follows.

[0045] (1) Stirring the molten pool to improve the material's microstructure and properties: In this invention, the laser beam deflection and the power of each laser change periodically. When a molten pool is formed on the base material, the laser beam pressure and energy flow will exert a certain pushing or dragging force on the molten pool, thereby playing the role of stirring the molten pool, and further refining the grains to improve the material's microstructure and properties.

[0046] (2) Avoid spherical droplets and improve droplet quality: Deflect the laser mirror so that its axis is not parallel to the axis of the wire feeding gun tube. The laser mirror guides the laser beam path to be incident on the base material at a certain angle deviating from the axis of the wire feeding gun tube and the metal wire, thus avoiding the appearance of spherical metal droplets.

[0047] (3) Improve welding accuracy and reduce thermal stress: Pure resistance heat melting of metal wire has the problem of poor welding effect between each weld pass. This invention uses laser heat to guide resistance heat. The laser mirror is deflected and arranged around the wire feeding gun tube. The laser beam path is deviated from the metal wire, so that the laser cannot directly enter the metal wire, but enters the focal point of the contact between the metal wire and the base material and its surrounding area. Based on resistance heat melting of metal wire, the problem of poor side melting effect is effectively solved and welding accuracy is improved.

[0048] (4) Improve heat input and thermal efficiency: This invention combines laser heat and resistance heat to preheat the metal wire, improve heat input and thermal efficiency, reduce the temperature difference between the base material and the metal wire, and thus reduce thermal stress.

[0049] (5) Extend the service life of the laser mirror: Since the laser mirror cannot achieve absolute light transmission, it will reflect or absorb some light. As a result, the laser mirror will generate a serious heat phenomenon during long-term operation. The laser mirror cooling system of the present invention can avoid the laser mirror from being damaged by heat.

[0050] (6) Extend the service life of the wire feeding gun barrel: Since the wire feeding gun barrel is affected by laser reflection, heat conduction of metal wire, heat radiation and resistance heat, the wire feeding gun barrel cooling system of the present invention can prevent the gun head temperature from being too high and causing damage to other components. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0052] Figure 2 This is the front view of Embodiment 1 of the present invention.

[0053] Figure 3 This is a front view sectional view of Embodiment 1 of the present invention.

[0054] Figure 4 This is a side view sectional view of Embodiment 1 of the present invention.

[0055] Figure 5 This is a top view of Embodiment 1 of the present invention.

[0056] Figure 6 This is a schematic diagram of the structure of the laser mirror deflection arrangement on the wire feeding gun barrel in Embodiment 1 of the present invention.

[0057] Figure 7This is a schematic diagram of the multiple laser incident optical paths and light spots in Embodiment 1 of the present invention.

[0058] Figure 8 This is the present invention. Figure 7 A magnified schematic diagram of the multiple laser incident optical path and spot in Example 1.

[0059] Figure 9 This is a schematic diagram of the direction of the photoelectric thrust in Embodiment 1 of the present invention.

[0060] Figure 10 This is a schematic diagram of the direction of light spot power change in Embodiment 1 of the present invention.

[0061] Figure 11 yes Figure 3 An enlarged schematic diagram of the wire feeding system in the front view sectional view of Embodiment 1 of the present invention.

[0062] Figure 12 This is a timing diagram of the laser spot power in Embodiment 1 of the present invention.

[0063] Figure 13 This is a schematic diagram of the cladding pattern after laser stirring of the molten pool in Embodiment 1 of the present invention.

[0064] Figure 14 This is a schematic diagram illustrating the heating principle of the resistance-heated molten metal wire in Embodiment 1 of the present invention.

[0065] Figure 15 This is a schematic diagram showing the material anisotropy of a single resistive thermal filament in existing technology.

[0066] Figure 16 This is a schematic diagram of the reflection formed after a laser beam is incident on the substrate using existing technology.

[0067] Figure 17 This is a schematic diagram of existing technology where a laser beam and a metal wire are fused together in the same plane to form a metal droplet.

[0068] In the diagram: 1. Laser mirror mounting housing; 101. Laser mirror mounting housing water cooling tank; 2. Laser mirror water cooling block; 21. Laser mirror water cooling block outlet; 22. Laser mirror water cooling block inlet; 23. Laser mirror water cooling block water tank; 3. Laser mirror; 31. Laser interface; 32. Collimating lens; 33. Focusing lens; 34. Protective lens; 4. Proximal wire feeding assembly body; 5. Wire feeding wheel fixing block; 6. Active wire feeding wheel; 7. Wire feeding wheel clamping mechanism; 8. Nut; 9. Protective air inlet. 10. Air inlet, 11. Water inlet for gun head cooling, 12. Inlet for gun head wire feed tube, 13. Water outlet for gun head cooling, 14. Cable outlet for gun head, 15. Driven wire feed wheel connecting block, 16. Screw, 17. Driven wire feed gear, 18. Driven wire feed gear, 19. Driven wire feed wheel, 20. Wire feed conductive nozzle, 21. Wire feed gun barrel, 22. Proximity wire feed motor, 23. Wire feed assembly viewing cover, 24. Metal wire, 25. Spring, 26. Base material, 27. Optical path, 28. Light spot (e.g.) Figure 9 The diagram shows the distribution of C1 to C6 in a clockwise direction. Detailed Implementation

[0069] The technical solution of the present invention will now be clearly and completely described in conjunction with the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0070] Example 1: Implementation Reference for this Example Figure 1-14 In this embodiment, the laser source consists of six lasers (not shown in the figure), which are symmetrically arranged in a ring around the periphery of the wire feeding tube 20, corresponding to six laser mirrors 3. These six laser mirrors 3 are arranged clockwise around the periphery of the wire feeding tube 20. The six lasers are one or more combinations of external fiber-coupled solid-state diode lasers, external fiber-coupled diode-pumped solid-state lasers, internal fiber-coupled solid-state diode lasers, and internal fiberless solid-state diode lasers.

[0071] Among them, additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools includes:

[0072] a. A wire feeding system, the wire feeding system consists of a drive mechanism (such as...) Figure 4 Driven by the near-end wire feeding motor 21 shown, the metal wire 23 is transmitted through the wire feeding gun barrel 20 and the wire feeding conductive nozzle 19 to the focal point of the laser spot 27 and the base material 25.

[0073] b. The laser mirrors 3 are deflected around the wire feeding gun barrel 20. The axes of the six laser mirrors 3 in the figure are not coplanar with the axes of the wire feeding gun barrel 20 and the metal wire 23. The laser mirrors 3 are used to adjust the laser beam path and deliver the laser beam to the focal point of the metal wire 23 and the base material 25.

[0074] c. The electric heating metal wire, the wire feeding nozzle 19 and the base material 25 are respectively connected to an external heating power supply (e.g., Figure 14 As shown, a current loop is formed between the heating power supply, the metal wire 23 and the base material 25. When the power is applied, the metal wire 23 generates resistance heat, which in turn preheats and assists the laser light source in melting the metal wire 23.

[0075] The cooling system is used to cool the wire feed gun barrel 20 and the laser mirror 3;

[0076] e. Protective gas system, the protective gas system is used to deliver protective gas to the focal point of the metal wire 23, the laser spot 27 and the base material 25;

[0077] It can adjust the laser path by deflecting the laser mirror 3 arranged around the wire feeding gun tube 20 by b, and perform additive manufacturing by using the electrothermal metal wire to assist in preheating the laser light source, melting the metal wire 23, and stirring the molten pool by c.

[0078] In this embodiment, the laser mirror 3 is internally arranged with a laser interface 31, a collimating lens 32, a focusing lens 33, and a protective lens 34 arranged sequentially from top to bottom. The axis of the laser mirror 3 is not coplanar with the axis of the metal wire 23. The collimating lens 32 and the focusing lens 33 can be adjusted in position via threads, thereby adjusting the focal length and focus of the laser mirror 3.

[0079] In this embodiment, the laser light spot 27 incident on the base material 25 is elliptical, and the axis of the elliptical light spot 27 is not coplanar with the axis of the metal wire 23. The laser beam path 26 does not directly hit the metal wire 23, but deviates from the axis of the metal wire 23, and the angle between the laser beam path 26 and the metal wire 23 and the base material 25 is an acute angle, between 10 and 80 degrees. In this embodiment, the angle between the laser beam path 26 and the metal wire 23 is 30 degrees, and the angle with the base material is 60 degrees, forming a laser-guided thermal preheating and joint melting of the metal wire 23 to manufacture metal parts. Figure 12As shown, the power of each laser exhibits periodic changes. Within a period, the power of each laser increases or decreases sequentially according to the clockwise deflection arrangement of the laser mirrors 3. When forming a molten pool on the base material, the average power of the laser spot in the direction of movement of the metal wire 23 is higher than the power of the laser spot in other directions. In this embodiment, the power variation range of each laser is 0W-200W, the power variation period is 1000Hz, and the positive defocusing amount is 5mm. The laser pressure component along the plane of the laser spot 27 generates a pushing or dragging force on the molten pool. Under the action of the periodic change in laser power, the energy flow together pushes or drags the molten pool, thereby stirring the molten pool. In this embodiment, as... Figure 9 The direction of the light pressure thrust shown is clockwise along C1~C6 of light spot 27, as follows: Figure 10 The high-power beam pattern shown also changes clockwise along C1~C6 of beam spot 27. The combined effect of the beam pressure thrust and the beam power change causes the molten pool to flow clockwise, thereby stirring the molten pool and forming a pattern like... Figure 13 The cladding pattern shown is the result of laser stirring of the molten pool.

[0080] The wire feeding system includes a driving wire feeding gear 16 and a driven wire feeding gear 17. The driving and driven wire feeding gears 16 and 17 are connected by a transmission mechanism, driving the driving wire feeding wheel 6 and the driven wire feeding wheel 18. The driving and driven wire feeding wheels 6 and 18 press the metal wire 23 and continuously transmit the metal wire 23 to the focal point of the laser spot 27 and the base material 25. The wire feeding system also includes a wire feeding wheel clamping mechanism 7. The wire feeding wheel clamping mechanism 7 is connected to one of the driving or driven wire feeding wheels 6 via a fixing block, and achieves bidirectional clamping between the driving and driven wire feeding wheels 6 and 18 through clamping force on one of them. The wire feeding wheel clamping mechanism 7 has an internal elastic mechanism, which in this embodiment is a spring 24. The elastic mechanism is connected to a telescopic mechanism, which in this embodiment includes a wire feeding wheel clamping nut 8 and a wire feeding wheel clamping screw 15.

[0081] Specifically, it also includes: the main body 4 of the proximal wire feeding assembly is fixedly connected to the upper part of the laser mirror fixing housing 1; the proximal wire feeding motor 21 is fixedly connected to the main body 4 of the proximal wire feeding assembly; the output shaft of the proximal wire feeding motor 21 is connected to the active wire feeding gear 16; the active wire feeding gear 16 is connected to the driven wire feeding gear 17 in a transmission connection; the driven wire feeding gear 17 is fixedly connected to the active wire feeding wheel 6 and is connected to the wire feeding wheel fixing block 5 through a pin; the wire feeding wheel fixing block 5 is fixedly connected to the main body 4 of the proximal wire feeding assembly; the driven wire feeding wheel 18 is connected to the driven wire feeding wheel connecting block 14 through a pin; and the driven wire feeding wheel connecting block 14 is connected to the wire feeding wheel fixing block 5 through a pin.

[0082] Specifically, the wire feeding wheel clamping mechanism 7 is fixedly connected to the near-end wire feeding assembly body 4. A spring 24 is provided inside the wire feeding wheel clamping mechanism 7. The spring 24 is sleeved on the wire feeding wheel clamping screw 15, and its left side contacts the wire feeding wheel clamping nut 8. The wire feeding wheel clamping nut 8 is threadedly connected to the wire feeding wheel clamping screw 15 and is relatively fixed. The two can slide left and right together under the action of spring force.

[0083] The clamping principle of the wire feeding wheel clamping mechanism 7: Under the action of spring force, the wire feeding wheel clamping nut 8 and the wire feeding wheel clamping screw 15 slide left and right, driving the driven wire feeding wheel connecting block 14, which in turn causes a clamping force to be generated between the driving wire feeding wheel 6 and the driven wire feeding wheel 18, thereby clamping the metal wire 23. The clamping force can be read from the display on the wire feeding wheel clamping mechanism 7. The clamping force between the driving wire feeding wheel 6 and the driven wire feeding wheel 18 is positively correlated with the spring force.

[0084] Laser mirror water cooling system: The laser mirror 3 is connected to the inside of the laser mirror fixing housing 1. The laser mirror cooling system is a laser mirror water cooling block 2, which is set around the laser mirror 3. The laser mirror water cooling block 2 includes a laser mirror water cooling block outlet 21, a laser mirror water cooling block inlet 22, and a laser mirror water cooling block water tank 23. The laser mirror water cooling block water tank 23 is set inside the laser mirror fixing housing 1, while the laser mirror water cooling block outlet 21 and the laser mirror water cooling block inlet 22 are set outside the laser mirror fixing housing 1.

[0085] Water cooling system for wire feeding gun barrel: The main body 4 of the proximal wire feeding assembly is connected to the upper part of the laser mirror fixing housing 1. The cooling system for the wire feeding gun barrel includes a water cooling inlet 10 and a water cooling outlet 12. The water cooling inlet 10 and the water cooling outlet 12 are respectively connected to the main body 4 of the proximal wire feeding assembly and externally connected to a water cooling inlet pipe and a water cooling outlet pipe. The laser mirror fixing housing 1 is provided with a laser mirror fixing housing water cooling tank 101. The laser mirror fixing housing water cooling tank 101 is symmetrically arranged on both sides of the wire feeding gun barrel 20, which can cool the wire feeding gun barrel 20.

[0086] Metal wire preheating system: The wire feeding gun barrel 20 is fixedly connected to the laser mirror fixing housing 1, and the wire feeding conductive nozzle 19 is connected to the wire feeding gun barrel 20 via threads; the wire feeding conductive nozzle 19 and the base material 25 are externally connected to a heating power supply, and when energized, it can preheat the metal wire 23 and the part in contact with the base material 25. The wire feeding conductive nozzle 19 can also be externally connected to an induction coil (not shown in the figure) to preheat the extruded metal wire 23.

[0087] Protective gas system: Inert gas such as Ar is delivered from the protective gas inlet 9 to the focal point of the metal wire 23, the laser spot 27 and the base material 25 for additive manufacturing atmosphere protection.

[0088] A wire feeding assembly viewing cover 22 is provided on one side of the path through which the metal wire 23 travels, allowing the operation of the metal wire 23 to be observed.

[0089] The wire feeding tube inlet 11 is connected to the main body 4 of the proximal wire feeding assembly, with an external wire feeding tube and an internal wire feeding gun barrel 20.

[0090] The gun head cable port 13 is connected to the near end wire feeding assembly body 4, and an external cable is connected.

[0091] An additive manufacturing method using an additive manufacturing apparatus with a deflected arrangement of multiple laser-stirred molten pools includes the following steps:

[0092] a. Heating wire: Turn on as follows Figure 14 The heating power supply connecting the wire feeding nozzle 19 and the base material 25, the wire feeding system conveys the metal wire 23 to the base material 25, and a current loop is formed between the heating power supply, the metal wire 23 and the base material 25 to generate resistance heat to preheat the metal wire 23 and the base material.

[0093] b. Laser-guided resistance thermoforming of metal wire: The laser mirror 3, which is deflected and arranged around the wire feeding gun tube 20, adjusts the laser beam path 26 and directs the laser to the focal point of the metal wire 23 and the base material 25. The laser beam path 26 is deviated from the metal wire 23, and the axis of the laser spot 27 is not coplanar with the metal wire 23. The laser thermoforming resistance thermoforming jointly melts the metal wire 23 for additive manufacturing.

[0094] c. The effect of laser light pressure and the periodic change of laser light on stirring the molten pool: The power of each laser exhibits periodic changes. The power of each laser increases or decreases in different time periods within a cycle according to the clockwise deflection arrangement of the laser mirror 3. When a molten pool is formed on the base material 25, the light pressure component along the plane of the laser spot 27 generates a pushing or dragging force on the molten pool. At the same time, under the effect of the periodic change of laser power, the energy flow together pushes or drags the molten pool to flow, thereby stirring the molten pool.

[0095] Example 2: The laser source consists of six lasers (not shown in the figure), corresponding to six laser mirrors 3 arranged symmetrically in a ring around the periphery of the wire feeding gun tube 20. The six laser mirrors 3 are arranged alternately, either clockwise or counterclockwise, with adjacent laser mirrors 3 symmetrically positioned. The laser power emitted by the three clockwise-deflected laser mirrors 3 is greater than that emitted by the three counterclockwise-deflected laser mirrors 3, thus still creating a clockwise stirring effect on the molten pool. When the laser power emitted by the three counterclockwise-deflected laser mirrors 3 is greater than that emitted by the three clockwise-deflected laser mirrors 3, a counterclockwise stirring effect on the molten pool is created.

[0096] At the same time, this arrangement method can effectively reduce the negative effects of laser reflection on the laser mirror 3 in symmetrical positions, such as laser mirror overheating and short service life.

[0097] When the number of laser mirrors 3 is an even number and symmetrically arranged, the above-mentioned staggered clockwise or counterclockwise deflection arrangement method can be used. When the number of laser mirrors 3 is an odd number and symmetrically arranged, there is no problem of laser reflection causing the laser mirrors 3 to heat up.

[0098] To those skilled in the art, the above embodiments are exemplary and non-limiting. The scope of protection of the present invention is not limited by the above embodiments, and no reference numerals in the claims should be construed as limiting the scope of protection of the claims.

[0099] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. 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. Therefore, they should not be construed as limitations on this invention.

Claims

1. An additive manufacturing equipment with multiple laser stirring molten pools arranged in a deflected configuration, characterized in that: It includes a wire feeding system, which is driven by a drive mechanism and is capable of conveying metal wire through the wire feeding gun barrel and the wire feeding conductive nozzle to the focal point of the laser spot and the base material; A laser mirror is deflected around the wire feeding gun barrel. The laser mirror is connected to a laser light source and is used to adjust the laser beam path to deliver the laser beam to the focal point between the metal wire and the base material. The deflection arrangement means that the axis of the laser mirror is not coplanar with the axis of the wire feeding gun barrel. The laser light source consists of no less than two lasers. In the electrothermal metal wire system, the wire feeding conductive nozzle and the base material are respectively connected to an external heating power source, forming a current loop between the heating power source, the metal wire and the base material. When energized, the metal wire generates resistance heat, thereby preheating and assisting the laser light source in melting the metal wire. A cooling system is used to cool the wire feed gun barrel and the laser mirror; A protective gas system for delivering protective gas to the focal point of the metal wire, the laser spot, and the base material; This additive manufacturing equipment can adjust the laser path by deflecting the laser mirrors arranged around the wire feeding gun barrel, and use an electrothermal metal wire system to assist in preheating the laser source, melting the metal wire, and stirring the molten pool for additive manufacturing. The power of each laser exhibits periodic changes. Within a cycle, the power of each laser increases or decreases sequentially according to the clockwise or counterclockwise deflection of the laser mirrors at different time points. When a molten pool is formed on the base material, the laser pressure along the laser spot plane generates a pushing or dragging force on the molten pool, thereby pushing or dragging the molten pool to flow and stirring the molten pool.

2. The additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools according to claim 1, characterized in that: The laser light source incident on the substrate is a non-circular spot, and the axis of the non-circular spot is not coplanar with the axis of the wire feed gun tube, and the laser beam path deviates from the axis of the wire feed gun tube.

3. The additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools according to claim 2, characterized in that: The light spot can be elliptical, annular, crescent-shaped, triangular, or rectangular.

4. The additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools according to claim 2, characterized in that: The laser mirror is arranged from top to bottom as follows: laser interface, collimating lens, focusing lens, and protective lens, or laser interface, focusing lens, and protective lens, arranged from top to bottom.

5. The additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools according to claim 4, characterized in that: The collimating lens and focusing lens can be adjusted in position via an adjustment mechanism, thereby adjusting the focal length and focus of the laser mirror.

6. The additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools according to claim 2, characterized in that: The laser is one or more of the following: an externally coupled solid-state diode laser, an externally coupled diode-pumped solid-state laser, an internally coupled solid-state diode laser, and an internally fiberless solid-state diode laser.

7. The additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools according to claim 2, characterized in that: The laser mirror axis has an angle of 10-80 degrees with the wire feed gun tube axis and an angle of 10-80 degrees with the base material.

8. The additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools according to claim 7, characterized in that: The laser mirror axis is at a 30-degree angle to the wire feed gun barrel axis and at a 60-degree angle to the base material.

9. The additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools according to claim 2, characterized in that: The number of lasers is 2-16, with an equal number of laser mirrors.

10. The additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools according to claim 1, characterized in that: The wire feeding system also includes a wire feeding wheel clamping mechanism. The wire feeding wheel clamping mechanism is connected to one of the active wire feeding wheel or the driven wire feeding wheel through a fixed block, and the active wire feeding wheel and the driven wire feeding wheel are clamped in both directions through the linkage of the fixed block.

11. The additive manufacturing equipment with deflected arrangement of multiple laser stirring molten pools according to claim 1, characterized in that: The cooling system includes a laser mirror cooling system and a wire feed gun barrel cooling system, and the cooling system is water-cooled.

12. An additive manufacturing method using an additive manufacturing apparatus with a deflected arrangement of multiple laser-stirred molten pools as described in any one of claims 1-11: Its features are: It includes the following steps: Electric heating metal wire: Turn on the heating power supply connecting the wire feeding nozzle and the base material, and a current loop is formed between the heating power supply, the metal wire and the base material to generate resistance heat to preheat the metal wire and the base material; Laser-guided resistive thermal melting of metal wire: The laser mirror, which is deflected and arranged in the wire feeding gun tube, adjusts the laser beam path and directs the laser beam to the focal point of the metal wire and the base material. The laser beam path is deviated from the metal wire, and the laser spot axis is not coplanar with the metal wire. The laser thermally guided resistor preheats and melts the metal wire. Laser pressure and periodic laser variation stir the molten pool: The power of each laser varies periodically. The power of each laser increases or decreases sequentially at different time points within a cycle according to the clockwise or counterclockwise deflection of the laser mirrors. When a molten pool is formed on the base material, the laser pressure component along the laser spot plane generates a pushing or dragging force on the molten pool. Under the action of periodic laser power variation, the energy flow together pushes or drags the molten pool, thereby stirring the molten pool.

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