Double-laser composite additive manufacturing device and additive manufacturing method thereof

Abstract

The invention provides a double-laser composite additive manufacturing device and an additive manufacturing method thereof.The double-laser composite additive manufacturing device comprises a first optical set, a second optical set and a forming chamber, the first optical set and the second optical set are arranged above the forming chamber and are close to the two ends of the forming chamber respectively, a forming cylinder is arranged in the forming chamber, and the first optical set and the second optical set are arranged in the forming chamber; the forming cylinder is used for bearing a printing material and a printing piece, the first optical group and the second optical group respectively emit Gaussian light and flat-top light to cure the printing material and form on a forming plane at the top of the forming cylinder, and a first powder cylinder and a second powder cylinder are arranged in the forming chamber. According to the double-laser composite additive manufacturing device and the additive manufacturing method thereof provided by the invention, regions with different grain sizes are arranged in a metal piece in a mode of processing a metal material region by Gaussian laser and flat-topped laser, a soft region and a hard region in heterogeneous deformation induction strengthening are constructed, and the deformation of the metal piece is enhanced by utilizing the synergistic effect of the soft region and the hard region. And therefore, the strength and plasticity of the additive manufacturing metal component are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a dual-laser composite additive manufacturing device and an additive manufacturing method thereof. Background Art

[0002] Stereolithography technology has a wide range of applications in new product development, complex shape parts manufacturing, large parts manufacturing, mold design and manufacturing, etc. However, the traditional single light source single galvanometer SLA printing technology: the resolution of this technology is limited by the size of a single light source, and the continuous curing area can only be scanned repeatedly without losing accuracy, which reduces the printing efficiency. Although increasing the beam diameter can increase the printing speed, it will inevitably lose accuracy. Therefore, although SLA technology has high printing accuracy, the printing speed is too slow and the time cost is high. In order to solve the above technical problems, modern technology has proposed some innovative solutions. For example, patent document CN112060570A discloses a photocuring printing method based on dual light sources and dual galvanometers. This method uses dual light sources and dual galvanometers to enable the additive manufacturing device to print prints quickly and with high precision, but the prints may not be strong enough due to different printing methods, which may cause cracking. Summary of the invention

[0003] The embodiment of the present invention provides a dual-laser composite additive manufacturing device and an additive manufacturing method thereof, so as to solve the problem that the strength of the printed parts printed by the additive manufacturing device in the prior art is not high.

[0004] To achieve the above-mentioned purpose, the embodiment of the present invention adopts the following technical scheme: a dual-laser composite additive manufacturing device, comprising a first optical group, a second optical group and a forming chamber, wherein the first optical group and the second optical group are arranged above the forming chamber, and the first optical group and the second optical group are respectively close to two ends of the forming chamber, a forming cylinder is arranged in the forming chamber, and the forming cylinder is used to carry printing materials and printed parts, and the first optical group and the second optical group respectively emit Gaussian light and flat top light to solidify the printing materials and form them on the forming plane at the top of the forming cylinder;

[0005] A first powder cylinder and a second powder cylinder are provided in the forming chamber, and the first powder cylinder and the second powder cylinder are symmetrically arranged on both sides of the forming cylinder. A first guide rail and a second guide rail parallel to the forming plane are provided in the forming chamber, and a third guide rail and a fourth guide rail driven by the first guide rail and moving along the length direction of the first guide rail are provided on the first guide rail, a first powder absorber driven by the third guide rail and moving along the length direction of the third guide rail is provided on the third guide rail, a second powder absorber driven by the fourth guide rail and moving along the length direction of the fourth guide rail is provided on the fourth guide rail, a scraper driven by the second guide rail and moving along the length direction of the second guide rail is provided on the second guide rail, and the scraper has a first station, a second station, a third station and a fourth station on the second guide rail, the first station makes the bottom of the scraper set between the first powder cylinder and the forming chamber frame, the second station makes the bottom of the scraper set between the first powder cylinder and the forming cylinder, the third station makes the bottom of the scraper set between the forming cylinder and the second powder cylinder, and the fourth station makes the bottom of the scraper set between the second powder cylinder and the forming chamber frame.

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

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

[0008] Furthermore, an air valve is provided in the forming chamber.

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

[0010] An additive manufacturing method using a dual-laser composite additive manufacturing device, using the dual-laser composite additive manufacturing device according to the above, has the following operating steps:

[0011] S1: adding low thermal crack sensitivity metal powder material and high thermal crack sensitivity metal powder material to the first powder tank and the second powder tank respectively;

[0012] S2: The first powder cylinder rises one layer, so that the powder overflows the first powder cylinder, and the layer thickness is between 30μm and 80μm; the forming cylinder descends one layer, and the layer thickness is between 30μm and 80μm. The layer thickness of the first powder cylinder when it rises is greater than the layer thickness of the forming cylinder when it descends;

[0013] S3: The scraper starts to work, and moves from the first station on the second guide rail to the third station and then returns to the first station, thereby bringing the metal powder with low thermal crack sensitivity on the first powder cylinder to the forming plane and filling the forming plane;

[0014] S4: the first optical group and the second optical group start working, and on the same layer of powder on the forming plane, the first optical group and / or the second optical group emits laser to process the metal powder area with low thermal crack sensitivity;

[0015] S5: The first powder absorber starts working, and moves the position of the first powder absorber through the first guide rail and the third guide rail to absorb the excess low thermal crack sensitivity metal powder on the forming plane. After completing the powder absorption work, the first powder absorber returns to the initial position;

[0016] S6: The scraper moves from the first station to the fourth station, and the second powder cylinder rises one layer, so that the powder overflows from the second powder cylinder, and the layer thickness is between 30μm and 80μm. The position of the forming cylinder remains unchanged, and the scraper moves from the fourth station to the second station and then returns to the fourth station, bringing the highly thermal crack-sensitive metal powder on the second powder cylinder to the surrounding area of ​​the forming plane to fill 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 emits laser to process the forming plane;

[0018] S8: The second powder absorber starts working and moves through the first guide rail and the fourth guide rail to absorb the excess high thermal crack sensitive metal powder on the forming plane and its left side. After completing the powder absorption work, the second powder absorber returns to the initial position;

[0019] S9: After the current layer is formed, steps S2 to S9 are repeated until the overall manufacturing of the heterogeneous metal component with high / low thermal crack sensitivity is completed.

[0020] Further, in step s4 and / or step s7, the first optical group emits Gaussian laser to process the middle area of ​​the forming plane, and the second optical group emits flat top laser to process the surrounding area of ​​the forming plane.

[0021] The beneficial effects of the present invention are:

[0022] The dual-laser composite additive manufacturing device and additive manufacturing method provided by the present invention arrange metal material areas into different grain size areas by alternately printing metal material areas with Gaussian laser and flat-top laser, construct soft zones and hard zones in heterogeneous deformation induced strengthening, and utilize the synergistic effect of soft and hard zones to improve the strength and plasticity of additively manufactured metal components. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention;

[0024] Figure 2 Schematic diagram of the scraper's working state.

[0025] Description of reference numerals:

[0026] 1. First optical group; 101. Laser; 102. Collimator; 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 absorber; 11. Second powder absorber; 12. Scraper; 121. First station; 122. Second station; 123. Third station; 124. Fourth station; 13. Inert gas bottle; 14. Gas valve; 15. Forming cylinder. DETAILED DESCRIPTION

[0027] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present application, and is not used to limit the present application.

[0028] like Figure 1-2 As shown, an embodiment of the present invention provides a dual-laser composite additive manufacturing device, comprising a first optical group 1, a second optical group 2 and a forming chamber 3, wherein the first optical group 1 and the second optical group 2 are arranged above the forming chamber 3, and the first optical group 1 and the second optical group 2 are respectively close to two ends of the forming chamber 3, a forming cylinder 15 is arranged in the forming chamber 3, and the forming cylinder 15 is used to carry printing materials and printed parts, and the first optical group 1 and the second optical group 2 respectively emit Gaussian light and flat top light to solidify the printing materials and form them on a forming plane at the top of the forming cylinder 15 (the forming plane refers to a plane formed by the model being stacked layer by layer during the printing process);

[0029] The first optical group 1 and the second optical group 2 each include a laser 101, a collimator 102, a galvanometer 103, and a focusing mirror 104 (the laser 101 is a device that generates a laser beam such as Gaussian light. The laser 101 in the present invention generates Gaussian light, with a laser wavelength of about 1064nm and a laser power of 200-1000W; the collimator 102 is used to adjust the shape of the laser beam to make the laser beam emitted by the laser 101 more parallel; the galvanometer 103 is a pair of high-speed rotating reflectors, which is used to control the lateral movement of the laser beam on the forming plane of the forming cylinder 15; the focusing mirror 104 is used to focus the laser beam to a very small point to ensure that the laser can accurately solidify the material. The laser 101, the collimator 102, the galvanometer 103, and the focusing mirror 104 are all available in the prior art. There are multiple embodiments, laser 101, collimator 102, galvanometer 103 and focusing mirror 104), the laser 101 emits Gaussian light which passes through the collimator 102, galvanometer 103 and focusing mirror 104 in sequence and is projected onto the forming plane of the forming cylinder 15, the second optical group 2 also includes a beam shaping element 201, the beam shaping element 201 is arranged between the collimator 102 and the galvanometer 103, and is used to convert the Gaussian light emitted by the laser 101 into a flat top light (a beam shaping system for metal SLM printing is disclosed in the patent document with document number CN111796429B, which discloses in detail the detailed process of converting the Gaussian light emitted by the laser beam into a flat top light by passing through the beam shaping element 201, so the specific structure of the beam shaping element 201 is not repeated here);

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

[0031] The forming chamber 3 is provided with a first powder material cylinder 4 and a second powder material cylinder 5, which are symmetrically arranged on both sides of the forming cylinder 15, and the forming chamber 3 is provided with a first guide rail 6 and a second guide rail 7 parallel to the forming plane, and the first guide rail 6 is provided with a third guide rail 8 and a fourth guide rail 9 driven by the first guide rail 6 and moving along the length direction of the first guide rail 6, and the third guide rail 8 is provided with a first powder suction device 10 driven by the third guide rail 8 and moving along the length direction of the third guide rail 8, and the fourth guide rail 9 is provided with a third powder suction device 10 driven by the fourth guide rail 9 and moving along the length direction of the fourth guide rail 9. Two powder absorbers 11 (the first powder absorber 10 and the second powder absorber 11 are both used to clean the metal powder on the forming plane. The first powder absorber 10 and the second powder absorber 11 have multiple embodiments in the prior art. The specific structures of the first powder absorber 10 and the second powder absorber 11 are not repeated here). The second guide rail 7 is provided with a scraper 12 driven by the second guide rail 7 and moving along the length direction of 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 the scraper 12 can scrape and clean the printing material on the forming plane. 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 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, and 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.

[0032] In order to prevent material oxidation and improve printing quality, as a preferred embodiment of the present invention, the dual-laser composite additive manufacturing device also includes an inert gas cylinder 13, which is connected to the forming chamber 3 through a pipeline. The inert gas cylinder 13 is used to contain inert gases such as Ar and transport the inert gas to the inside 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 multiple embodiments in the prior art, and the specific structure of the inert gas cylinder 13 is not described in detail here); in order to better discharge the gas inside the forming chamber 3, as a preferred embodiment of the present invention, a gas valve 14 is provided in the forming chamber 3 (the gas valve 14 has multiple embodiments in the prior art, and the specific structure of the gas valve 14 is not described in detail here).

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

[0034] An additive manufacturing method using a dual-laser composite additive manufacturing device has the following operating steps:

[0035] S1: Adding low thermal crack sensitivity metal powder material and high thermal crack sensitivity metal powder material into the first powder tank 4 and the second powder tank 5 respectively;

[0036] S2: The first powder cylinder 4 rises by one layer, so that the powder overflows from the first powder cylinder 4, and the layer thickness is between 30μm and 80μm; the forming cylinder 15 descends by one layer, and the layer thickness is between 30μm and 80μm. The rising layer thickness of the first powder cylinder 4 must be greater than the descending layer thickness of the forming cylinder 15;

[0037] S3: the scraper 12 starts to work, and 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 metal powder with low thermal crack sensitivity 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 emits laser to process the forming plane (i.e., the metal powder area with low thermal crack sensitivity), that is, the first optical group 1 emits Gaussian laser to process the metal powder area with low thermal crack sensitivity or the second optical group 2 emits laser to process the metal powder area with low thermal crack sensitivity, so as to obtain a structure in which the coarse and fine grain regions present a layered distribution, or the first optical group 1 emits Gaussian laser to process the middle area of ​​the forming plane, and the second optical group 2 emits flat-top laser to process the surrounding area of ​​the forming plane, so that the particles in the middle area are smaller than those in the surrounding areas, thereby inducing a heterogeneous deformation strengthening mechanism to synergistically strengthen the strength and plasticity of the metal component;

[0039] S5: The first powder absorber 10 starts working, and moves the position of the first powder absorber 10 through the first guide rail 6 and the third guide rail 8 to absorb the excess low thermal crack sensitivity metal powder on the forming plane. After completing the powder absorption work, the first powder absorber 10 returns to the initial position;

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

[0042] S8: The second powder absorber 11 starts working, and moves through the first guide rail 6 and the fourth guide rail 9 to absorb the excess high thermal crack sensitive metal powder on the forming plane and its left side. After completing the powder absorption work, the second powder absorber 11 returns to the initial position;

[0043] S9: After the current layer is formed, steps S3 to S9 are repeated until the overall manufacturing of the heterogeneous metal component with high / low thermal crack sensitivity is completed.

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

[0045] In summary, the dual-laser composite additive manufacturing device and its additive manufacturing method, through the method of processing metal material areas with Gaussian laser and flat-top laser, arrange the metal parts into regions with different grain sizes, construct soft zones and hard zones in heterogeneous deformation induced strengthening, and utilize the synergistic effect of soft and hard zones to improve the strength and plasticity of additively manufactured metal components.

[0046] The above-described embodiments only express the implementation methods of the present invention, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A dual-laser composite additive manufacturing device, characterized in that: The invention comprises a first optical group (1), a second optical group (2) and a forming chamber (3), wherein the first optical group (1) and the second optical group (2) are arranged above the forming chamber (3), and the first optical group (1) and the second optical group (2) are respectively close to two ends of the forming chamber (3), a forming cylinder (15) is arranged in the forming chamber (3), and the forming cylinder (15) is used to carry printing materials and printed parts, and the first optical group (1) and the second optical group (2) respectively emit Gaussian light and flat top light to solidify the printing materials and form them on the forming plane at the top of the forming cylinder (15); A first powder material cylinder (4) and a second powder material cylinder (5) are arranged in the forming chamber (3). The first powder material cylinder (4) and the second powder material cylinder (5) are symmetrically arranged on both sides of the forming cylinder (15). A first guide rail (6) and a second guide rail (7) parallel to the forming plane are arranged in the forming chamber (3). A third guide rail (8) and a fourth guide rail (9) driven by the first guide rail (6) and moving along the length direction of the first guide rail (6) are arranged on the first guide rail (6). A first powder absorber (10) driven by the third guide rail (8) and moving along the length direction of the third guide rail (8) is arranged on the third guide rail (8). A second powder absorber (11) driven by the fourth guide rail (9) and moving along the length direction of the fourth guide rail (9) is arranged on the fourth guide rail (9). The scraper (12) is driven by the second guide rail (7) and moves along the length direction 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 device according to claim 1, characterized in that: The first optical group (1) and the second optical group (2) both comprise a laser (101), a collimator (102), a galvanometer (103), and a focusing mirror (104). The laser (101) emits Gaussian light which passes through the collimator (102), the galvanometer (103), and the focusing mirror (104) in sequence and is projected onto a forming plane of a forming cylinder (15). The second optical group (2) further comprises a beam shaping element (201). The beam shaping element (201) is arranged between the collimator (102) and the galvanometer (103) and is used to convert the Gaussian light emitted by the laser (101) into flat-top light.

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

4. The dual laser composite additive manufacturing device according to claim 1, characterized in that: An air valve (14) is arranged in the forming chamber (3).

5. The dual laser composite additive manufacturing device according to claim 1, characterized in that: The dual-laser composite additive manufacturing device also includes two powder recovery cylinders, and the two powder recovery cylinders are respectively connected to the first powder absorber (10) and the second powder absorber (11) through pipelines.

6. An additive manufacturing method using a dual-laser composite additive manufacturing device, using the dual-laser composite additive manufacturing device according to any one of claims 1 to 5, characterized in that: The operation steps are as follows: S1: adding metal powder material with low thermal crack sensitivity and metal powder material with high thermal crack sensitivity to the first powder material tank (4) and the second powder material tank (5) respectively; S2: the first powder material cylinder (4) rises by one layer, so that the powder overflows from the first powder material cylinder (4), and the layer thickness is between 30 μm and 80 μm; the forming cylinder (15) descends by one layer, and the layer thickness is between 30 μm and 80 μm, and the layer thickness when the first powder material cylinder (4) rises is greater than the layer thickness when the forming cylinder (15) descends; S3: the scraper (12) starts to work, and 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 metal powder with low thermal crack sensitivity 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, and on the same layer of powder on the forming plane, the first optical group (1) and / or the second optical group (2) emit laser to process the metal powder area with low thermal crack sensitivity; S5: the first powder absorber (10) starts working, and moves the position of the first powder absorber (10) through the first guide rail (6) and the third guide rail (8) to absorb the excess low thermal crack sensitivity metal powder on the forming plane. After completing the powder absorption work, the first powder absorber (10) returns to the initial position; S6: the scraper (12) moves from the first station (121) to the fourth station (124), the second powder cylinder (5) rises one layer, so that the powder overflows from the second powder cylinder (5), the layer thickness is between 30 μm and 80 μm, 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), and the high thermal crack sensitive metal powder on the second powder cylinder (5) is brought to the surrounding area of ​​the forming plane, 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) emits laser to process the forming plane; S8: The second powder absorber (11) starts to work, and moves through the first guide rail (6) and the fourth guide rail (9) to absorb the excess high thermal crack sensitive metal powder on the forming plane and the left side thereof. After completing the powder absorption work, the second powder absorber (11) returns to the initial position; S9: After the current layer is formed, steps S2 to S9 are repeated until the overall manufacturing of the heterogeneous metal component with high / low thermal crack sensitivity is completed.

7. The method for using the dual-laser additive manufacturing device according to claim 6, characterized in that: In step s4 and / or step s7, the first optical group (1) emits Gaussian laser to process the middle area of ​​the forming plane, and the second optical group (2) emits flat top laser to process the surrounding area of ​​the forming plane.

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