Dual laser compound additive manufacturing device and additive manufacturing method thereof

Abstract

This invention provides a dual-laser composite additive manufacturing apparatus and method, comprising a first optical group, a second optical group, and a forming chamber. The first and second optical groups are positioned above the forming chamber, respectively close to both ends of the forming chamber. A forming cylinder is provided within the forming chamber to hold printing material and a printed part. The first and second optical groups emit Gaussian and flat-top lasers, respectively, to cure the printing material and form it on a forming plane at the top of the forming cylinder. A first and second powder cylinders are also provided within the forming chamber. The dual-laser composite additive manufacturing apparatus and method provided by this invention, through the processing of metal material regions using Gaussian and flat-top lasers, arranges regions of different grain sizes within the metal part, constructing soft and hard regions in heterogeneous deformation-induced strengthening. Utilizing the synergistic effect of these soft and hard regions, the strength and plasticity of the additively manufactured metal component are improved.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, specifically to a dual-laser composite additive manufacturing apparatus and its additive manufacturing method. Background Technology

[0002] Photopolymerization technology has wide applications in new product development, manufacturing of complex-shaped parts, manufacturing of large parts, and mold design and manufacturing. However, traditional single-light source, single-mirror SLA printing technology has limitations: its resolution is limited by the size of the single light source, requiring repeated scanning of the continuous curing area without sacrificing accuracy, which reduces printing efficiency. Increasing the beam diameter can improve printing speed, but inevitably sacrifices accuracy. Therefore, while SLA technology offers high printing accuracy, its printing speed is too slow and its time cost is high. To address these technical problems, modern technologies have proposed some innovative solutions. For example, patent document CN112060570A discloses a photopolymerization printing method based on dual light sources and dual galvanometers. This method enables additive manufacturing devices to print parts quickly and with high accuracy using dual light sources and dual galvanometers; however, the strength of the printed parts may be low due to different printing methods, potentially leading to cracking. Summary of the Invention

[0003] This invention provides a dual-laser composite additive manufacturing apparatus and method to solve the problem of low strength of printed parts produced by existing additive manufacturing apparatuses.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a dual-laser composite additive manufacturing apparatus, comprising a first optical group, a second optical group, and a forming chamber. The first optical group and the second optical group are disposed above the forming chamber, and the first optical group and the second optical group are respectively close to the two ends of the forming chamber. A forming cylinder is disposed inside the forming chamber, which is used to carry printing material and printed parts. The first optical group and the second optical group respectively emit Gaussian light and flat-top light to cure the printing material and form it on the forming plane at the top of the forming cylinder.

[0005] The forming chamber is equipped with a first powder cylinder and a second powder cylinder, which are symmetrically arranged on both sides of the forming cylinder. The forming chamber is equipped with a first guide rail and a second guide rail parallel to the forming plane. A third guide rail and a fourth guide rail are arranged on the first guide rail, driven by the first guide rail and moving along the length of the first guide rail. A first powder suction device is arranged on the third guide rail, driven by the third guide rail and moving along the length of the third guide rail. A second powder suction device is arranged on the fourth guide rail, driven by the fourth guide rail and moving along the length of the fourth guide rail. A scraper is arranged on the second guide rail, driven by the second guide rail and moving along the length of the second guide rail. The scraper has a first station, a second station, a third station and a fourth station on the second guide rail. The first station positions the bottom of the scraper between the first powder cylinder and the frame of the forming chamber. The second station positions the bottom of the scraper between the first powder cylinder and the forming cylinder. The third station positions the bottom of the scraper between the forming cylinder and the second powder cylinder. The fourth station positions the bottom of the scraper between the second powder cylinder and the frame of the forming chamber.

[0006] Furthermore, both the first and second optical groups include a laser, a collimating lens, a galvanometer, and a focusing lens. The laser emits Gaussian light that passes sequentially through the collimating lens, the galvanometer, and the focusing lens and is projected onto the forming plane of the forming cylinder. The second optical group also includes a beam shaping element, which is disposed between the collimating lens and the galvanometer to convert the Gaussian light emitted by the laser into flat-top light.

[0007] Furthermore, the dual-laser composite additive manufacturing apparatus also includes an inert gas cylinder, which is connected to the forming chamber via a pipeline.

[0008] Furthermore, an air valve is installed inside the forming chamber.

[0009] Furthermore, the dual-laser composite additive manufacturing apparatus also includes two powder recovery cylinders, and the two powder recovery cylinders are respectively connected to the first powder collector and the second powder collector pipes.

[0010] An additive manufacturing method utilizing a dual-laser composite additive manufacturing apparatus, comprising the following operational steps:

[0011] S1: Add low-thermal-crack-sensitive metal powder material and high-thermal-crack-sensitive metal powder material to the first powder cylinder and the second powder cylinder respectively.

[0012] S2: The first powder cylinder rises by one layer, causing the powder to overflow from the first powder cylinder. The layer thickness is between 30μm and 80μm. The forming cylinder descends by one layer, with a layer thickness between 30μm and 80μm. The layer thickness of the rising first powder cylinder is greater than the layer thickness of the descending forming cylinder.

[0013] S3: The scraper starts working. The scraper moves from the first station on the second guide rail to the third station and then returns to the first station, thereby bringing the low thermal cracking sensitive metal powder on the first powder cylinder to the forming plane and filling the forming plane.

[0014] S4: The first and second optical groups start working. On the same layer of powder on the forming plane, the first and / or second optical groups emit lasers to process the low thermal cracking sensitivity metal powder area.

[0015] S5: The first powder collector starts working. The position of the first powder collector is moved by the first guide rail and the third guide rail to remove the excess low thermal crack sensitivity metal powder on the forming plane. After the powder collection work is completed, the first powder collector returns to the initial position.

[0016] S6: The scraper moves from the first station to the fourth station, the second powder cylinder rises by one layer, causing the powder to overflow from the second powder cylinder. The layer thickness is between 30μm and 80μm. The position of the forming cylinder remains unchanged. The scraper moves from the fourth station to the second station and then returns to the fourth station, carrying the high heat crack sensitive metal powder on the second powder cylinder to the surrounding area of ​​the forming plane and filling the forming plane.

[0017] S7: On the same layer of powder on the forming plane, the first optical group and / or the second optical group emit lasers to process the forming plane;

[0018] S8: The second powder collector starts working and moves through the first and fourth guide rails to remove excess high thermal crack sensitive metal powder from the forming plane and its left side. After completing the powder collection work, the second powder collector returns to the initial position.

[0019] S9: After the current layer is formed, repeat steps S2 to S9 until the entire heterogeneous metal component with high / low thermal crack sensitivity is manufactured.

[0020] Furthermore, in steps s4 and / or s7, the first optical group emits a Gaussian laser to process the middle region of the shaped plane, and the second optical group emits a flat-top laser to process the surrounding region of the shaped plane.

[0021] The beneficial effects of this invention are as follows:

[0022] The dual-laser composite additive manufacturing apparatus and its additive manufacturing method provided by the present invention use Gaussian laser and flat-top laser to alternately print metal material regions, so that the metal parts are arranged into regions with different grain sizes, constructing soft and hard regions in heterogeneous deformation-induced strengthening, and utilizing the synergistic effect of soft and hard regions to improve the strength and plasticity of additively manufactured metal components. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 This is a schematic diagram of the working state of the scraper.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. First optical group; 101. Laser; 102. Collimating lens; 103. Galvanometer; 104. Focusing lens; 2. Second optical group; 201. Beam shaping element; 3. Forming chamber; 4. First powder cylinder; 5. Second powder cylinder; 6. First guide rail; 7. Second guide rail; 8. Third guide rail; 9. Fourth guide rail; 10. First powder suction device; 11. Second powder suction device; 12. Scraper; 121. First station; 122. Second station; 123. Third station; 124. Fourth station; 13. Inert gas cylinder; 14. Gas valve; 15. Forming cylinder. Detailed Implementation

[0027] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0028] like Figure 1-2 As shown, this embodiment of the invention provides a dual-laser composite additive manufacturing apparatus, including a first optical group 1, a second optical group 2, and a forming chamber 3. The first optical group 1 and the second optical group 2 are disposed above the forming chamber 3, and the first optical group 1 and the second optical group 2 are respectively close to the two ends of the forming chamber 3. A forming cylinder 15 is disposed inside the forming chamber 3. The forming cylinder 15 is used to carry the printing material and the printed part. The first optical group 1 and the second optical group 2 respectively emit Gaussian light and flat-top light to cure the printing material and form it on the forming plane at the top of the forming cylinder 15 (the forming plane refers to the plane formed by the layer-by-layer stacking of the model during the printing process).

[0029] Both the first optical group 1 and the second optical group 2 include a laser 101, a collimating lens 102, a galvanometer 103, and a focusing lens 104. (The laser 101 is a device that generates Gaussian light or other laser beams. In this invention, the laser 101 generates Gaussian light with a wavelength of approximately 1064 nm and a power of 200–1000 W. The collimating lens 102 is used to adjust the shape of the laser beam, making the laser beam emitted by the laser 101 more parallel. The galvanometer 103 is a pair of high-speed rotating mirrors used to control the lateral movement of the laser beam on the forming plane of the forming cylinder 15. The focusing lens 104 is used to focus the laser beam onto a very small point to ensure that the laser can accurately solidify the material. The laser 101, collimating lens 102, galvanometer 103, and focusing lens 104 all have...) There are multiple embodiments (laser 101, collimating lens 102, galvanometer 103, and focusing lens 104). The laser 101 emits Gaussian light that passes sequentially through the collimating lens 102, galvanometer 103, and focusing lens 104 and is projected onto the forming plane of the forming cylinder 15. The second optical group 2 also includes a beam shaping element 201, which is disposed between the collimating lens 102 and the galvanometer 103. It is used to convert the Gaussian light emitted by the laser 101 into flat-top light (a beam shaping system for metal SLM printing is disclosed in patent document CN111796429B, which details the process of converting the emitted Gaussian light into flat-top light by the laser beam passing through the beam shaping element 201. Therefore, the specific structure of the beam shaping element 201 will not be described in detail here).

[0030] The Gaussian laser spot projected onto the forming plane by the first optical group 1 is a circular spot with a diameter between 40 and 80 μm, and the energy distribution shows that the energy is high in the middle region and low in the surrounding region. The flat-top laser spot projected onto the forming plane by the second optical group 2 is a circular spot with a diameter between 90 and 120 μm, and the energy distribution is uniform, that is, the energy density of the middle region and the surrounding region is the same.

[0031] The forming chamber 3 is equipped with a first powder cylinder 4 and a second powder cylinder 5, which are symmetrically arranged on both sides of the forming cylinder 15. The forming chamber 3 is also equipped with a first guide rail 6 and a second guide rail 7 parallel to the forming plane. A third guide rail 8 and a fourth guide rail 9 are mounted on the first guide rail 6, driven by the first guide rail 6 and moving along its length. A first powder suction device 10 is mounted on the third guide rail 8, driven by the third guide rail 8 and moving along its length. A fourth powder suction device 10 is mounted on the fourth guide rail 9, driven by the fourth guide rail 9 and moving along its length. Two powder suction devices 11 (both the first powder suction device 10 and the second powder suction device 11 are used to clean metal powder on the forming surface; the first powder suction device 10 and the second powder suction device 11 have various embodiments in the prior art, and their specific structures are not described in detail here), and a scraper 12 driven by the second guide rail 7 and moving along the length of the second guide rail 7 is provided on the second guide rail 7, so that the bottom of the scraper 12 can pass through the top of the first powder cylinder 4, the second powder cylinder 5 and the forming cylinder 15, and so that the scraper 12 can scrape and clean the printing material on the forming surface, such as Figure 2 As shown, the scraper 12 has a first station 121, a second station 122, a third station 123 and a fourth station 124 on the second guide rail 7. The first station 121 positions the bottom of the scraper 12 between the first powder cylinder 4 and the frame of the forming chamber 3. The second station 122 positions the bottom of the scraper 12 between the first powder cylinder 4 and the forming cylinder 15. The third station 123 positions the bottom of the scraper 12 between the forming cylinder 15 and the second powder cylinder 5. The fourth station 124 positions the bottom of the scraper 12 between the second powder cylinder 5 and the frame of the forming chamber 3.

[0032] To prevent material oxidation and improve printing quality, in a preferred embodiment of the present invention, the dual-laser composite additive manufacturing apparatus further includes an inert gas cylinder 13. The inert gas cylinder 13 is connected to the forming chamber 3 via a pipe. The inert gas cylinder 13 is used to hold inert gases such as Ar and to deliver the inert gas to the interior of the forming chamber 3. By passing the inert gas into the forming chamber 3 through the inert gas cylinder 13, the oxygen content in the forming chamber 3 can be reduced to below 25 ppm (the inert gas cylinder 13 has various embodiments in the prior art, and its specific structure will not be described here). In order to better exhaust the gas inside the forming chamber 3, in a preferred embodiment of the present invention, a gas valve 14 is provided inside the forming chamber 3 (the gas valve 14 has various embodiments in the prior art, and its specific structure will not be described here).

[0033] In order to enable the material recovered by the powder collector to be reused and prevent material waste, as a preferred embodiment of the present invention, the dual-laser composite additive manufacturing apparatus further includes two powder recovery cylinders, and the two powder recovery cylinders are respectively connected to the first powder collector 10 and the second powder collector 11 via pipes.

[0034] An additive manufacturing method utilizing a dual-laser composite additive manufacturing apparatus comprises the following operational steps:

[0035] S1: Add low-thermal-crack-sensitive metal powder material and high-thermal-crack-sensitive metal powder material to the first powder cylinder 4 and the second powder cylinder 5 respectively.

[0036] S2: The first powder cylinder 4 rises by one layer, causing the powder to overflow from the first powder cylinder 4. The layer thickness is between 30μm and 80μm. The forming cylinder 15 descends by one layer, with a layer thickness between 30μm and 80μm. The layer thickness of the first powder cylinder 4 when it rises must be greater than the layer thickness of the forming cylinder 15 when it descends.

[0037] S3: The scraper 12 starts working. The scraper 12 moves from the first station 121 on the second guide rail 7 to the third station 123 and then returns to the first station 121, thereby bringing the low thermal cracking sensitive metal powder on the first powder cylinder 4 to the forming plane and filling the forming plane.

[0038] S4: The first optical group 1 and the second optical group 2 start working. On the same layer of powder on the forming plane, the first optical group 1 and / or the second optical group 2 emit lasers to process the forming plane (i.e., the low thermal crack sensitivity metal powder area). That is, the first optical group 1 emits a Gaussian laser to process the low thermal crack sensitivity metal powder area or the second optical group 2 emits a laser to process the low thermal crack sensitivity metal powder area, thereby obtaining a structure in which the coarse and fine grain areas are distributed in a layered manner. Alternatively, the first optical group 1 emits a Gaussian laser to process the middle area of ​​the forming plane, and the second optical group 2 emits a flat-top laser to process the surrounding area of ​​the forming plane, so that the particles in the middle area are smaller than the particles in the surrounding area, thereby inducing a heterogeneous deformation strengthening mechanism to synergistically strengthen the strength and plasticity of the metal component.

[0039] S5: The first powder suction device 10 starts working and moves its position through the first guide rail 6 and the third guide rail 8 to suck away excess low thermal crack sensitivity metal powder on the forming plane. After the powder suction work is completed, the first powder suction device 10 returns to its initial position.

[0040] S6: The scraper 12 moves from the first station 121 to the fourth station 124, the second powder cylinder 5 rises by one layer, causing the powder to overflow from the second powder cylinder 5. The layer thickness is between 30μm and 80μm. The position of the forming cylinder 15 remains unchanged. The scraper 12 moves from the fourth station 124 to the second station 122 and then returns to the fourth station 124, bringing the high thermal crack-sensitive metal powder on the second powder cylinder 5 to the surrounding area of ​​the forming plane and filling the forming plane.

[0041] S7: On the same layer of powder on the forming plane, the second optical group 2 emits a flat-top laser to process the forming plane (i.e., the region of metal powder with high thermal crack sensitivity);

[0042] S8: The second powder suction device 11 starts working and moves through the first guide rail 6 and the fourth guide rail 9 to suck away the excess high thermal crack sensitive metal powder on the forming plane and its left side. After the powder suction work is completed, the second powder suction device 11 returns to the initial position.

[0043] S9: After the current layer is formed, repeat steps S3 to S9 until the entire heterogeneous metal component with high / low thermal crack sensitivity is manufactured.

[0044] In order to induce a heterogeneous deformation strengthening mechanism to synergistically enhance the strength and plasticity of metal components, in one embodiment of the present invention, in steps s4 and / or s7, the first optical group 1 emits a Gaussian laser to process the middle region of the shaped plane, thereby obtaining a fine grain structure. The laser power can be selected from 200 to 1000 W, and the scanning speed can be selected from 200 mm / s to 1500 mm / s. The second optical group 2 emits a flat-top laser to process the surrounding region of the shaped plane, thereby obtaining a coarse grain structure. The laser power can be selected from 200 to 1000 W, and the scanning speed can be selected from 200 mm / s to 1500 mm / s.

[0045] In summary, this dual-laser composite additive manufacturing device and its additive manufacturing method use Gaussian lasers and flat-top lasers to process metal material regions, thereby arranging regions of different grain sizes within the metal part and constructing soft and hard regions in heterogeneous deformation-induced strengthening. By utilizing the synergistic effect of soft and hard regions, the strength and plasticity of additively manufactured metal components are improved.

[0046] The embodiments described above merely illustrate implementation methods of the present invention and should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A dual-laser composite additive manufacturing apparatus, characterized in that, It includes a first optical group (1), a second optical group (2) and a forming chamber (3). The first optical group (1) and the second optical group (2) are located above the forming chamber (3) and are close to the two ends of the forming chamber (3). A forming cylinder (15) is provided inside the forming chamber (3). The forming cylinder (15) is used to carry the printing material and the printed parts. The first optical group (1) and the second optical group (2) emit Gaussian light and flat-top light respectively to cure the printing material and form it on the forming plane at the top of the forming cylinder (15). The forming chamber (3) is equipped with a first powder cylinder (4) and a second powder cylinder (5), which are symmetrically arranged on both sides of the forming cylinder (15). The forming chamber (3) is equipped with a first guide rail (6) and a second guide rail (7) parallel to the forming plane. The first guide rail (6) is equipped with a third guide rail (8) and a fourth guide rail (9) driven by the first guide rail (6) and moving along the length of the first guide rail (6). The third guide rail (8) is equipped with a first powder suction device (10) driven by the third guide rail (8) and moving along the length of the third guide rail (8). The fourth guide rail (9) is equipped with a second powder suction device (11) driven by the fourth guide rail (9) and moving along the length of the fourth guide rail (9). The second guide rail (7) is equipped with a first powder suction device (10) driven by the third guide rail (8) and moving along the length of the third guide rail (8). The second guide rail (7) drives the scraper (12) to move along the length of the second guide rail (7). The scraper (12) has a first station (121), a second station (122), a third station (123) and a fourth station (124) on the second guide rail (7). The first station (121) sets the bottom of the scraper (12) between the first powder cylinder (4) and the frame of the forming chamber (3). The second station (122) sets the bottom of the scraper (12) between the first powder cylinder (4) and the forming cylinder (15). The third station (123) sets the bottom of the scraper (12) between the forming cylinder (15) and the second powder cylinder (5). The fourth station (124) sets the bottom of the scraper (12) between the second powder cylinder (5) and the frame of the forming chamber (3).

2. The dual-laser composite additive manufacturing apparatus according to claim 1, characterized in that, The first optical group (1) and the second optical group (2) both include a laser (101), a collimating lens (102), a galvanometer (103), and a focusing lens (104). The laser (101) emits Gaussian light that passes sequentially through the collimating lens (102), the galvanometer (103), and the focusing lens (104) and is projected onto the forming plane of the forming cylinder (15). The second optical group (2) also includes a beam shaping element (201), which is disposed between the collimating lens (102) and the galvanometer (103) to convert the Gaussian light emitted by the laser (101) into flat-top light.

3. The dual-laser composite additive manufacturing apparatus according to claim 1, characterized in that, The dual-laser composite additive manufacturing apparatus also includes an inert gas cylinder (13), which is connected to the forming chamber (3) via a pipeline.

4. The dual-laser composite additive manufacturing apparatus according to claim 1, characterized in that, An air valve (14) is installed inside the forming chamber (3).

5. The dual-laser composite additive manufacturing apparatus according to claim 1, characterized in that, The dual-laser composite additive manufacturing apparatus also includes two powder recovery cylinders, which are respectively connected to the first powder collector (10) and the second powder collector (11) via pipes.

6. An additive manufacturing method utilizing a dual-laser composite additive manufacturing apparatus, comprising the dual-laser composite additive manufacturing apparatus according to any one of claims 1-5, characterized in that, The operation steps are as follows: S1: Add low thermal crack sensitivity metal powder material and high thermal crack sensitivity metal powder material to the first powder cylinder (4) and the second powder cylinder (5) respectively; S2: The first powder cylinder (4) rises by one layer, causing the powder to overflow from the first powder cylinder (4), with a layer thickness between 30μm and 80μm; the forming cylinder (15) descends by one layer, with a layer thickness between 30μm and 80μm, and the layer thickness of the rising first powder cylinder (4) is greater than the layer thickness of the descending forming cylinder (15). S3: The scraper (12) starts working. The scraper (12) moves from the first station (121) on the second guide rail (7) to the third station (123) and then returns to the first station (121), thereby bringing the low thermal crack sensitivity metal powder on the first powder cylinder (4) to the forming plane and filling the forming plane. S4: The first optical group (1) and the second optical group (2) start working. On the same layer of powder on the forming plane, the first optical group (1) and / or the second optical group (2) emit lasers to process the low thermal crack sensitivity metal powder area. S5: The first powder collector (10) starts working and moves its position through the first guide rail (6) and the third guide rail (8) to remove excess low thermal crack sensitivity metal powder on the forming plane. After the powder collection work is completed, the first powder collector (10) returns to its initial position. S6: The scraper (12) moves from the first station (121) to the fourth station (124), the second powder cylinder (5) rises by one layer, causing the powder to overflow from the second powder cylinder (5), with a layer thickness between 30μm and 80μm. The position of the forming cylinder (15) remains unchanged. The scraper (12) moves from the fourth station (124) to the second station (122) and then returns to the fourth station (124), bringing the high heat crack sensitive metal powder on the second powder cylinder (5) to the surrounding area of ​​the forming plane and filling the forming plane. S7: On the same layer of powder on the forming plane, the first optical group (1) and / or the second optical group (2) emit lasers to process the forming plane; S8: The second powder suction device (11) starts working and moves through the first guide rail (6) and the fourth guide rail (9) to suck away the excess high thermal crack sensitive metal powder on the forming plane and its left side. After the powder suction work is completed, the second powder suction device (11) returns to the initial position. S9: After the current layer is formed, repeat steps S2 to S9 until the entire heterogeneous metal component with high / low thermal crack sensitivity is manufactured.

7. The additive manufacturing method using a dual-laser composite additive manufacturing apparatus according to claim 6, characterized in that, In step S4 and / or step S7, the first optical group (1) emits a Gaussian laser to process the middle region of the shaped plane, and the second optical group (2) emits a flat-top laser to process the surrounding region of the shaped plane.

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