A galvanometer scanning coaxial composite dual-laser melting deposition device and method

Abstract

The present invention relates to a galvanometer scanning coaxial composite dual-laser melting deposition device, which includes a fixing fixture, a small-spot light source, a large-spot light source, a galvanometer system, a focusing lens, and a laser beam combiner mounted on the fixing fixture. Among them, the output laser of the small-spot light source forms a first laser through the galvanometer system, and the output laser of the large-spot light source forms a second laser through the focusing lens. The laser beam synthesized by the two lasers through the laser beam combiner is focused on the wire / powder to be melted and deposited. The present invention also relates to a galvanometer scanning coaxial composite dual-laser melting deposition method. The purpose of the galvanometer scanning coaxial composite dual-laser melting deposition device and method is to solve the problem that the surface roughness is relatively high due to the input of a large-size heat source after the existing laser melting deposition process.

Description

Technical Field

[0001] The present invention relates to the technical field of fused deposition additive manufacturing, and particularly relates to a galvanometer scanning coaxial composite dual-laser fused deposition device and method. Background Art

[0002] For the efficient additive preparation and repair of high-performance structural materials such as existing ultra-high-strength steel and titanium alloy, melting methods such as laser melting deposition and arc are used. Melting deposition methods including coaxial, off-axis, and central powder and wire feeding will have obvious large undulations in the formed grooves, high surface roughness after processing, and corresponding turning, polishing, and grinding are required after melting deposition, resulting in high processing costs.

[0003] At present, the molten tracks on the surface of the molten deposition layer of the conventional laser melting deposition technology are relatively obvious, the grooves are large and uneven, and corresponding post-treatments such as turning, grinding, and polishing are required after melting deposition, resulting in high processing costs. In addition, the surface undulations on the molten deposition surface during the laser melting deposition process will continuously accumulate, and then there will be a large difference in the thermal history between local regions of the molten deposition, which will affect the mechanical properties of the overall component and it is difficult to meet the use requirements.

[0004] Therefore, the inventor provides a galvanometer scanning coaxial composite dual-laser fused deposition device and method. Summary of the Invention

[0005] (1) Technical Problems to be Solved

[0006] The embodiments of the present invention provide a galvanometer scanning coaxial composite dual-laser fused deposition device and method, which solve the technical problem that the existing laser melting deposition has a high surface roughness due to the input of a large-size heat source after processing.

[0007] (2) Technical Solutions

[0008] The present invention provides a galvanometer scanning coaxial composite dual-laser fused deposition device, including a fixed tooling and a small-spot light source, a large-spot light source, a galvanometer system, a focusing lens, and a laser beam combiner installed on the fixed tooling; wherein,

[0009] The first laser formed by the output laser of the small-spot light source through the galvanometer system and the second laser formed by the output laser of the large-spot light source through the focusing lens are combined by the laser beam combiner and focused on the wire / powder to be melted and deposited.

[0010] Further, the wavelength of the output laser of the small-spot light source is 515 nm.

[0011] Further, the wavelength of the output laser of the large-spot light source is 1070 nm.

[0012] Further, the galvanometer scanning coaxial composite dual-laser melting deposition device further includes an antireflection film, and the antireflection film is attached to the end face of the laser beam combiner facing the first laser.

[0013] Further, the galvanometer scanning coaxial composite dual-laser melting deposition device further includes a total reflection film, and the total reflection film is attached to the end face of the laser beam combiner facing the second laser.

[0014] Further, the included angle between the laser beam combiner and the horizontal plane is 45°.

[0015] Further, the output laser of the small spot light source is parallel to the output laser of the large spot light source.

[0016] Further, the focusing mirror is located at the middle position between the large spot light source and the laser beam combiner.

[0017] The present invention also provides a galvanometer scanning coaxial composite dual-laser melting deposition method, which uses the above-mentioned galvanometer scanning coaxial composite dual-laser melting deposition device, and includes the following steps:

[0018] Slice the part digital model layer by layer, and form the scanning trajectory of each layer slice according to the width and overlap rate of a single pass weld bead.

[0019] Fix the substrate on the workbench, and place the laser head above the substrate.

[0020] Feed the wire / powder below the laser head, and the large spot laser melts and deposits the wire / powder and is coaxially irradiated and converged to the melting deposition area by the small spot laser, and reciprocally scans the path in the deposited area that has melted but not solidified to remelt the molten pool generated by the melting deposition.

[0021] The laser melts and deposits layer by layer and remelts the molten pool according to the scanning trajectory generated for each layer until all the scanning trajectories of the part digital model are completed.

[0022] Further, the reciprocating scanning direction of the small spot laser is perpendicular to the melting deposition direction of the large spot laser.

[0023] (3) Beneficial effects

[0024] In summary, the present invention coaxially combines and converges lasers with different wavelengths emitted by the large spot light source and the small spot light source to the melting deposition area. Among them, the large spot laser first irradiates and melts the powder or wire along the scanning direction, and the small spot laser remolds the molten pool along the set scanning path in the molten state area, completing the precise control of the weld bead size and morphology, and further realizing laser melting deposition with high surface quality and high forming accuracy, and the structure of the entire melting deposition device is more compact. Description of the drawings

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments of the present invention. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0026] Figure 1 is a schematic structural diagram of a galvanometer scanning coaxial composite dual-laser melting deposition device provided by an embodiment of the present invention;

[0027] Figure 2 is a schematic diagram of the working directions of a large-spot laser and a small-spot laser provided by an embodiment of the present invention;

[0028] Figure 3 is another schematic diagram of the working directions of a large-spot laser and a small-spot laser provided by an embodiment of the present invention;

[0029] Figure 4 is a schematic flowchart of a galvanometer scanning coaxial composite dual-laser melting deposition method provided by an embodiment of the present invention.

[0030] In the figure:

[0031] 1 - Fixed tooling; 2 - Small-spot light source; 3 - Large-spot light source; 4 - Galvanometer system; 5 - Focusing mirror; 6 - Laser beam combiner; 7 - Anti-reflection coating; 8 - Total reflection film; 9 - Optical fiber; 10 - Manipulator; 11 - Delivery pipe; 12 - Inert gas protection box; 100 - Substrate; 200 - Melting deposition area; 300 - Liquid molten pool; 400 - Solidified molten pool area; 500 - Large-spot melting deposition direction; 600 - Small-spot scanning direction. Detailed implementation manners

[0032] The following will further describe in detail the implementation manners of the present invention in combination with the drawings and embodiments. The detailed descriptions and drawings of the following embodiments are used to exemplarily illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments, and covers any modifications, substitutions, and improvements of parts, components, and connection methods without departing from the spirit of the present invention.

[0033] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will refer to the drawings and combine the embodiments to detail the present application.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the products of the present invention are customarily placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0035] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set" and "installed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] Figure 1 is a schematic structural diagram of a galvanometer scanning coaxial composite dual-laser melting deposition device provided by an embodiment of the present invention. The device may include a fixed fixture 1 and a small-spot light source 2, a large-spot light source 3, a galvanometer system 4, a focusing lens 5, and a laser beam combiner 6 installed on the fixed fixture 1;

[0037] The output laser of the small-spot light source 2 forms a first laser through the galvanometer system 4, and the output laser of the large-spot light source 3 forms a second laser through the focusing lens 5. The laser beam synthesized by the laser beam combiner 6 is focused on the wire / powder to be melted and deposited.

[0038] In the above embodiment, the melting deposition laser emitted by the large-spot light source 3 is reflected by the total reflection film of the laser beam combiner and converges to the melting deposition area 200. At the same time, the small-sized spot emitted by the small-spot light source 2 is coaxially irradiated and converges to the melting deposition area 200 under the action of the antireflection film of the laser beam combiner 6 after the optical path is adjusted by the galvanometer system 4.

[0039] Among them, as Figures 2 - 3 shown, the melting deposition laser first irradiates and melts the powder or wire along the scanning direction, and the small-spot laser re-forms the molten pool along the set scanning path in the molten state area. The galvanometer scans the molten pool and can be inside, behind, and in front of the melting deposition laser molten pool. The scanning size can be larger or smaller than the diameter of the melting deposition laser molten pool. The reciprocating scanning direction of the galvanometer system 4 is perpendicular to the laser melting deposition path, or the galvanometer scanning path is circular. Melting deposition is carried out on the surface of high-performance parts such as ultra-high-strength steel or titanium alloy at a certain moving speed to complete the precise control of the melt channel size and morphology, and then realize high-surface-quality and high-forming-precision laser melting deposition.

[0040] Among them, the fixing fixture 1 is fixed on the manipulator 10 or the machine tool moving device, and the melting deposition of each layer is carried out according to the scanning trajectory generated by slicing the digital model layer by layer.

[0041] As an alternative embodiment, the wavelength of the output laser of the small spot light source 2 is 515. Among them, the laser output by the small spot light source 2 is preferably a small-sized spot with a wavelength of about 515 nm, and the laser enters the small spot light source 2 through the optical fiber 9.

[0042] As an alternative embodiment, the wavelength of the output laser of the large spot light source 3 is 1070 nm. Among them, the laser output by the large spot light source 3 is preferably a melting deposition laser with a wavelength of about 1070 nm, and the laser enters the large spot light source 3 through the optical fiber 9.

[0043] As an alternative embodiment, the galvanometer scanning coaxial composite dual-laser melting deposition device further includes an anti-reflection film 7, and the anti-reflection film 7 is attached to the end face of the laser beam combiner 6 facing the first laser. Among them, the setting of the anti-reflection film 7 helps the laser output by the small spot light source 2 to completely transmit through the laser beam combiner 6 and converge to the melting deposition area.

[0044] As an alternative embodiment, the galvanometer scanning coaxial composite dual-laser melting deposition device further includes a total reflection film 8, and the total reflection film 8 is attached to the end face of the laser beam combiner 6 facing the second laser. Among them, the setting of the total reflection film 8 helps the laser output by the large spot light source 3 to completely reflect out of the laser beam combiner 6 and converge to the melting deposition area.

[0045] As an alternative embodiment, the angle between the laser beam combiner 6 and the horizontal plane is 45°. Specifically, this angle is set to satisfy that the first laser and the second laser can converge at the same point to achieve the melting deposition of the wire / powder.

[0046] As an alternative embodiment, the output laser of the small spot light source 2 and the output laser of the large spot light source 3 are parallel to each other. Specifically, such a setting method is to satisfy that the first laser and the second laser can converge at the same point to achieve the melting deposition of the wire / powder.

[0047] As an alternative embodiment, the focusing mirror 5 is located at the middle position between the large spot light source 3 and the laser beam combiner 6. Among them, such a setting of the focusing mirror 5 is to facilitate the multi-beam lasers output by the large spot light source 3 to converge at the same point on the substrate 100 after being reflected by the laser beam combiner 6.

[0048] As an alternative embodiment, as Figure 1 shown, the split-beam laser coaxial melting deposition device further includes a delivery pipe 11, and the output end of the delivery pipe 11 is located directly below the center position of the laser beam combiner 6 and is used to transfer the wire / powder to the substrate 100.

[0049] Specifically, the delivery pipe 11 can be fixed directly below the central position of the laser head housing 1 through a fixing bracket. The delivery pipe 11 can deliver wire or powder according to actual requirements, and a flexible PVC pipe can be selected.

[0050] As an alternative embodiment, as Figure 1 shown, the split-beam laser coaxial melting deposition device further includes an inert gas protection box 12, which is used to place the wire / powder to be melted and deposited and the fixing tooling 1. Among them, the inert gas is used for dust prevention and cooling of the lens.

[0051] Of course, it can also be to pass inert gas at the installation positions of the galvanometer, focusing lens and laser beam combining lens inside the fixing tooling 1.

[0052] Figure 4 FIG. is a schematic flow chart of a galvanometer scanning coaxial composite dual-laser melting deposition method provided by an embodiment of the present invention. The method may include the following steps:

[0053] S100. Slice the part digital model layer by layer, and form the scanning trajectory of each layer of slice according to the width and overlap rate of a single-pass melt track;

[0054] S200. Fix the substrate on the workbench and place the laser head above the substrate;

[0055] S300. Feed the wire or powder below the laser head. The large-spot laser melts and deposits the wire or powder and irradiates and converges it coaxially through the small-spot laser to the melting and deposition area, and repeatedly scans the path in the deposited area that has melted but not solidified to remelt the molten pool generated by the melting and deposition;

[0056] S400. The laser melts and deposits layer by layer and remelts the molten pool according to the scanning trajectory generated for each layer until all the scanning trajectories of the part digital model are completed.

[0057] In the above-described embodiment, two laser sources are coaxially integrated and fixed on a manipulator or a machine tool moving device. The melting deposition laser source is a fiber laser with a wavelength of approximately 1070 nm, and the small spot light source is a disk laser with a wavelength of approximately 515 nm. The parallel melting deposition laser transmitted horizontally is focused by a focusing mirror, and then converges after being reflected by the total reflection film of the laser beam combiner, so that the laser focus converges on the wire or powder fed coaxially, realizing melting deposition. The convergence point of the melting deposition laser is higher than the surface of the deposition substrate. The small-sized spot is coaxially irradiated and converges to the melting deposition area under the action of the antireflection film of the same plane mirror after the optical path is adjusted by the galvanometer system, and remolds the molten pool along the set scanning path in the deposited area that has melted but not solidified, completing the transformation from a large-sized molten pool to a micro-molten pool. According to the shape of the melting deposition area on the part surface, a melting deposition scanning trajectory is formed according to a lap rate of 20-90%, and through the combined action with the small-sized spot, high-surface-quality scanning deposition is achieved using a manipulator or a machine tool.

[0058] Example 1

[0059] Taking the laser melting deposition and surface shaping of titanium alloy as an example, the specific implementation process is as follows:

[0060] 1. Slice the digital model of the titanium alloy part layer by layer, and form a scanning trajectory according to the width of a single melting channel and a lap rate of 50%.

[0061] 2. Fix the forming substrate on the workbench. Specifically: Use a manipulator to clamp two laser heads, place them above the substrate, keep them horizontal, measure the laser convergence point and keep it 10 mm above the deposition surface.

[0062] 3. Feed a 0.8-1 mm titanium alloy wire into the laser head using a wire feeding tube, or send 20-250 μm titanium alloy powder through an air carrier powder feeder using a powder feeding tube. The wire / powder melts and deposits on the substrate after passing through the laser convergence point.

[0063] 4. The small-sized spot is coaxially irradiated and converges to the melting deposition area almost simultaneously, and remolds the molten pool generated by melting deposition along the "Zig-zag" reciprocating scanning path in the deposited area that has melted but not solidified. The reciprocating scanning direction of the galvanometer is perpendicular to the laser melting deposition path, or the galvanometer scanning path can be circular.

[0064] 5. Start laser melting deposition after the oxygen content in the inert gas protection box is lower than 1000 ppm.

[0065] 6. Turn on the wire feeder / powder feeder and the laser. Melt and deposit the coaxially fed wire or powder after the laser scanning converges. The laser power is 500 - 3000 W. The powder / wire feeding tube scans and moves at a speed of 10 - 20 mm / s. At the same time, a small-sized light spot further shapes the molten pool according to the reciprocating scanning strategy, and the laser power is 200 - 1000 W. The manipulator performs melting deposition according to the scanning trajectory generated for each layer.

[0066] 7. The manipulator lifts by a layer thickness of 50 - 300 μm and starts the next layer to repeat melting deposition and remelting of the molten pool until all the part digital models are scanned.

[0067] 8. Turn off the laser and the wire feeder / powder feeder. After the part cools to room temperature, take it out of the inert gas protection box.

[0068] It should be clear that the various embodiments in this specification are described in a progressive manner. For the same or similar parts between the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. And, for the sake of brevity, the detailed description of known method technologies is omitted here.

[0069] The above are only the embodiments of this application and do not limit this application. For those skilled in the art, various changes and modifications can be made to this application without departing from the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the scope of the claims of this application.

Claims

1. A galvanometer scanning coaxial composite double laser melting deposition device, characterized in that It includes a fixed tooling (1), as well as a small-spot light source (2), a large-spot light source (3), a galvanometer system (4), a focusing lens (5), and a laser beam combiner (6) mounted on the fixed tooling (1); among them, The first laser formed by the output laser of the small-spot light source (2) through the galvanometer system (4) and the second laser formed by the output laser of the large-spot light source (3) through the focusing lens (5) are focused by the laser beam combiner (6) onto the wire / powder to be melted and deposited; The included angle between the laser beam combiner (6) and the horizontal plane is 45°, so as to ensure that the first laser and the second laser converge at the same point; It further includes an anti-reflection film (7), and the anti-reflection film (7) is attached to the end face of the laser beam combiner (6) facing the first laser; It further includes a total reflection film (8), and the total reflection film (8) is attached to the end face of the laser beam combiner (6) facing the second laser; The melting and deposition laser emitted by the large-spot light source (3) is reflected by the total reflection film of the laser beam combiner and converges to the melting and deposition area (200). At the same time, the small-size spot emitted by the small-spot light source (2) is coaxially irradiated and converges to the melting and deposition area (200) under the action of the anti-reflection film of the laser beam combiner (6) after the optical path is adjusted by the galvanometer system (4); the molten pool is reshaped along the set scanning path in the deposited area that has been melted but not solidified, completing the transformation from a large-size molten pool to a micro-molten pool; The fixed tooling (1) is fixed on a manipulator (10) or a machine tool motion device.

2. The galvanometer scanning coaxial composite dual-laser melting deposition device according to claim 1, wherein, The wavelength of the output laser of the small-spot light source (2) is 515 nm.

3. The galvanometer scanning coaxial composite dual-laser melting deposition device according to claim 1, wherein The wavelength of the output laser of the large-spot light source (3) is 1070 nm.

4. The galvanometer scanning coaxial composite dual-laser melting deposition device according to claim 1, wherein The output laser of the small-spot light source (2) and the output laser of the large-spot light source (3) are parallel to each other.

5. The galvanometer scanning coaxial composite dual-laser melting deposition device according to claim 1, wherein, The focusing lens (5) is located at the middle position between the large-spot light source (3) and the laser beam combiner (6).

6. A galvanometer scanning coaxial composite double laser melting deposition method, characterized in that, Using the galvanometer scanning coaxial composite double-laser melting and deposition device according to any one of claims 1-5, it includes the following steps: Slice the part digital model layer by layer, and form the scanning trajectory of each layer slice according to the width and overlap rate of a single-pass weld bead; Fix the substrate on the workbench, and place the laser head above the substrate; Feed the wire / powder under the laser head, and the large-spot laser melts and deposits the wire / powder and is coaxially irradiated and converged to the melting and deposition area by the small-spot laser, and the molten pool generated by the melting and deposition is remelted along the reciprocating scanning path in the deposited area that has been melted but not solidified; The laser melts and deposits layer by layer and remelts the molten pool according to the scanning trajectory generated for each layer until all the scanning trajectories of the part digital model are completed.

7. The galvanometer scanning coaxial composite double laser melting deposition method according to claim 6, wherein The reciprocating scanning direction of the small-spot laser is perpendicular to the melting and deposition direction of the large-spot laser.

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