A pressurized printing device for laser additive manufacturing

Abstract

The application belongs to the technical field of additive manufacturing, and discloses a pressurized printing device for laser additive manufacturing, which comprises a high-pressure cabin, a light-transmitting piece, a printing mechanism, a powder laying mechanism and a pressure adjusting mechanism, the high-pressure cabin is installed on a printer substrate of a laser powder bed melting equipment, the light-transmitting piece is arranged on the high-pressure cabin, the printing mechanism is arranged in the high-pressure cabin and is used for carrying powder and forming a printing layer, the powder laying mechanism is arranged on the printing mechanism and is used for laying powder layer by layer, and the pressure adjusting mechanism is connected with the high-pressure cabin and is used for adjusting the air pressure in the high-pressure cabin. The application can be directly installed on the printer substrate of the laser powder bed melting equipment without any modification on the original equipment. The inert gas is filled into the high-pressure cabin through the pressure adjusting mechanism, and the air pressure in the cabin can be increased to a preset value. The high-pressure environment significantly increases the boiling point of metal materials, reduces the evaporation and burning loss of elements in the laser melting process, and reduces the generation of smoke and dust and the shielding of the laser light path.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and more particularly to a pressure printing apparatus for laser additive manufacturing. Background Technology

[0002] Laser Powder Bed Fusion (LPBF), also known as Selective Laser Melting (SLM), is a typical metal additive manufacturing technology. This technology uses a high-energy laser beam to selectively melt powder materials, depositing them layer by layer to form complex structural parts. It is particularly suitable for metal materials such as magnesium alloys and zinc alloys that are difficult to process using traditional methods, and has broad application prospects in aerospace, biomedicine, and automotive lightweighting.

[0003] However, during laser powder bed melting, the interaction between the high-energy laser and the powder generates extremely high local temperatures, far exceeding the boiling points of most metals. For alloy systems containing volatile elements such as magnesium and zinc, this process can lead to severe volatilization problems. First, metal volatilization generates a large amount of fumes that diffuse within the forming chamber, obstructing the laser beam path and reducing the laser energy reaching the powder bed, thus affecting subsequent forming stability and the consistency of energy input. Second, the preferential volatilization of volatile elements causes the molten pool composition to deviate from the design target, resulting in uneven chemical composition of the final formed part and a significant decrease in mechanical properties and corrosion resistance. Furthermore, the gases generated by volatilization cannot escape the molten pool in time and are captured by the solidification front, forming pores within the material, reducing density and mechanical properties.

[0004] Therefore, effectively suppressing volatilization is a key technical issue in achieving high-quality laser powder bed fusion molding of volatile metallic materials. Currently, the main approaches to suppressing volatilization focus on temperature control, such as substrate preheating and optimizing parameters like laser power and scanning speed. However, improvements in temperature control are limited, and adjusting laser parameters involves multiple variables such as power, scanning speed, scanning spacing, and scanning strategy. This typically requires extensive experimental trial and error to obtain an optimal process window, and it is difficult to completely eliminate porosity defects. Summary of the Invention

[0005] In order to solve the technical problems existing in the prior art, the purpose of this invention is to provide a pressure printing device for laser additive manufacturing, which can be installed on existing equipment without major modifications to the host, and can realize high-density, low-defect laser powder bed melting and forming of volatile metal materials.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] This invention provides a pressure printing apparatus for laser additive manufacturing, comprising:

[0008] High-pressure chamber, which can be detachably installed on the printer substrate of the laser powder bed melting equipment, and forms a sealed printing space;

[0009] A light-transmitting element is disposed on the high-pressure chamber for allowing laser light to pass through and enter the interior of the high-pressure chamber;

[0010] A printing mechanism, disposed within the high-pressure chamber, is used to carry powder and form a printing layer;

[0011] A powder spreading mechanism is provided on the printing mechanism for spreading powder layer by layer;

[0012] A pressure regulating mechanism, which is connected to the high-pressure chamber, is used to regulate the air pressure inside the high-pressure chamber;

[0013] The powder spreading mechanism includes a powder storage bin and a powder spreading connecting rod. The powder storage bin is located inside the high-pressure chamber and is mounted on the printing mechanism. The powder spreading connecting rod is connected to the powder storage bin and can drive the powder storage bin to rotate to spread powder.

[0014] As a preferred embodiment of a pressure printing device for laser additive manufacturing, the high-pressure chamber includes a high-pressure chamber base, a high-pressure chamber body, and a high-pressure chamber cover. The high-pressure chamber base is mounted on the printer substrate, and the high-pressure chamber body and the high-pressure chamber base are detachably connected by a rotating locking mechanism. The high-pressure chamber cover is mounted on the high-pressure chamber body, so that the interior of the high-pressure chamber body forms a sealed container.

[0015] As a preferred embodiment of a pressure printing device for laser additive manufacturing, the rotating locking mechanism includes a protrusion and a recess. The protrusion is disposed on the outer side wall of the high-pressure chamber, and the recess is disposed on the inner side wall of the high-pressure chamber base. When the protrusion and the recess are aligned, the high-pressure chamber can be placed into the high-pressure chamber base and fixed by rotation locking.

[0016] As a preferred embodiment of a pressure printing device for laser additive manufacturing, the protrusion includes at least two latches, which are radially spaced along the high-pressure chamber. The recess includes a first retaining ring and a second retaining ring, which are axially spaced along the high-pressure chamber base. The first retaining ring has at least two slots along its circumference, which match the shape of the latches. The latches can pass through the slots and rotate to engage and fix with the first and second retaining rings.

[0017] As a preferred embodiment of a pressure printing device for laser additive manufacturing, the printing mechanism includes a printing stage, a printing platform, and a lifting and adjusting assembly. The printing stage is disposed within the high-pressure chamber and connected to the upper cover of the high-pressure chamber via a printing connecting rod. A printing channel is provided on the printing stage, and the printing platform is disposed within and slidably connected to the printing channel. The lifting and adjusting assembly is connected to the printing platform and is used to adjust the height of the printing platform so that a height difference is formed between the printing platform and the upper surface of the printing channel, so as to lay powder layer by layer on the printing platform.

[0018] As a preferred embodiment of a pressure printing device for laser additive manufacturing, the lifting and adjusting assembly includes a lifting platform and at least one lifting rod. The lifting platform is located below the printing stage, and the printing platform is mounted on the lifting platform. One end of the lifting rod is connected to the lifting platform, and the other end passes through the cover of the high-pressure chamber and is threaded with a dial. The dial rotates to drive the lifting rod to move up and down.

[0019] As a preferred embodiment of a pressure printing device for laser additive manufacturing, the powder spreading mechanism includes a powder storage bin and a powder spreading connecting rod. The powder storage bin is disposed on the printing stage. One end of the powder spreading connecting rod is connected to the powder storage bin, and the other end is movably connected to the top cover of the high-pressure chamber and protrudes from its surface. A powder spreading channel is provided on the powder storage bin. The powder spreading connecting rod can drive the powder storage bin to rotate. When the powder spreading channel coincides with the printing channel, the powder in the powder storage bin will fall into the printing channel through the powder spreading channel to spread the powder.

[0020] As a preferred embodiment of a pressure printing device for laser additive manufacturing, a flange is provided inside the high-pressure chamber, and a light-transmitting element is disposed between the flange and the upper cover of the high-pressure chamber. The upper cover of the high-pressure chamber has a light-transmitting channel corresponding to the position of the light-transmitting element so that the laser can pass through.

[0021] As a preferred embodiment of a pressure printing device for laser additive manufacturing, a first sealing ring is provided between the light-transmitting component, the high-pressure chamber cover, and the flange; a second sealing ring is provided between the high-pressure chamber cover and the high-pressure chamber body; a third sealing ring is provided between the high-pressure chamber body and the high-pressure chamber base; and a fourth sealing ring is provided between the high-pressure chamber base and the printer substrate.

[0022] As a preferred embodiment of a pressurized printing device for laser additive manufacturing, the pressure regulating mechanism includes an inlet pipe, an outlet pipe, and a pressure relief valve. One end of the inlet pipe is connected to an external compressed air cylinder, and the other end is connected to the upper part of the side wall of the high-pressure chamber. The outlet pipe is connected to the lower part of the side wall of the high-pressure chamber, and the pressure relief valve is installed on the outlet pipe.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) The pressurized printing device of the present invention adopts an independent high-pressure chamber structure, which can be directly installed on the printer substrate of the laser powder bed melting equipment without any modification to the original main structure, optical path system or control system. By filling the high-pressure chamber with inert gas through the pressure regulating mechanism, the pressure inside the chamber can be increased to a preset value. The high-pressure environment significantly increases the boiling point of the metal material, reduces element evaporation and burn-off during the laser melting process, and reduces the generation of smoke and dust and the shielding of the laser optical path. Therefore, it can effectively suppress the deviation of material composition, reduce internal porosity defects, and significantly improve the density and mechanical properties of the formed parts.

[0025] (2) The powder spreading mechanism of the present invention adopts a rotary design. The powder storage bin is rotated to the top of the printing channel by the powder spreading connecting rod to complete the powder spreading. At the same time, the lifting adjustment component adopts a threaded lifting rod with a scale. By rotating the scale, the descent height of the printing platform can be precisely controlled, realizing the precise control of the thickness of each powder layer and ensuring the uniformity and consistency of the printed layer thickness. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the overall structure of the pressure printing device for laser additive manufacturing described in this invention.

[0028] Figure 2 This is a schematic diagram of the disassembled structure of the high-pressure chamber described in this invention.

[0029] Figure 3 This is a schematic diagram of the printing mechanism and powder spreading mechanism described in this invention.

[0030] Figure 4 This is a schematic diagram of the disassembled structure of the printing mechanism described in this invention.

[0031] Figure 5 This is a schematic diagram of the powder spreading mechanism described in this invention.

[0032] Figure 6 This is a cross-sectional structural diagram of the high-pressure chamber described in this invention.

[0033] Figure 7 This is a schematic diagram of the pressure regulating mechanism described in this invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. High-pressure chamber; 11. High-pressure chamber base; 12. High-pressure chamber body; 13. High-pressure chamber top cover; 14. Rotating locking mechanism; 141. Buckle; 142. First retaining ring; 143. Second retaining ring; 144. Recess; 15. Flange; 16. Light transmission channel;

[0036] 2. Light-transmitting components;

[0037] 3. Printing mechanism; 31. Printing stage; 32. Printing platform; 33. Lifting and adjusting assembly; 331. Lifting platform; 332. Lifting rod; 333. Dial; 34. Printing connecting rod; 35. Printing channel;

[0038] 4. Powder spreading mechanism; 41. Powder storage bin; 42. Powder spreading connecting rod; 43. Powder spreading channel;

[0039] 5. Pressure regulating mechanism; 51. Inlet pipe; 52. Outlet pipe; 53. Pressure relief valve;

[0040] 6. First sealing ring; 7. Second sealing ring; 8. Third sealing ring; 9. Fourth sealing ring;

[0041] 100. Printer baseboard. Detailed Implementation

[0042] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0043] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0044] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present 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, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0045] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] like Figure 1 As shown, this invention provides a pressure printing apparatus for laser additive manufacturing, comprising: a high-pressure chamber 1, a light-transmitting element 2, a printing mechanism 3, a powder-spreading mechanism 4, and a pressure regulating mechanism 5. The high-pressure chamber 1 is mounted on the printer substrate 100 of a laser powder bed melting device. The light-transmitting element 2 is disposed on the high-pressure chamber 1 to allow the laser to pass through and enter the interior of the high-pressure chamber 1. The printing mechanism 3 is disposed inside the high-pressure chamber 1 to carry powder and form a printing layer. The powder-spreading mechanism 4 is disposed on the printing mechanism 3 to spread powder layer by layer. The pressure regulating mechanism 5 is connected to the high-pressure chamber 1 and is used to regulate the air pressure inside the high-pressure chamber 1.

[0047] refer to Figure 2 The high-pressure chamber 1 specifically includes a high-pressure chamber base 11, a high-pressure chamber body 12, and a high-pressure chamber top cover 13. The high-pressure chamber base 11 is fixedly mounted on the printer base plate 100 by bolts or other detachable means. The high-pressure chamber body 12 is detachably connected to the high-pressure chamber base 11 by a rotating locking mechanism 14. The high-pressure chamber top cover 13 is installed on top of the high-pressure chamber body 12, so that the interior of the high-pressure chamber body 12 forms a sealed printing container.

[0048] In this embodiment, the rotating engagement mechanism 14 preferably adopts the following structure to achieve a detachable connection:

[0049] The rotating locking mechanism 14 specifically includes a protrusion and a recess. The protrusion is located on the outer side wall of the high-pressure chamber 12, and the recess is located on the inner side wall of the high-pressure chamber base 11. When the protrusion and the recess are aligned, the high-pressure chamber 12 can be inserted into the high-pressure chamber base 11, and then locked in place by rotation. In this embodiment, the protrusion includes at least two latches 141, which are radially spaced along the high-pressure chamber 12. The recess includes a first retaining ring 142 and a second retaining ring 143, which are axially spaced along the high-pressure chamber base 11. The first retaining ring 142 has at least two slots 144 along its circumference, and the slots 144 match the shape of the latches 141. During installation, align the buckle 141 with the slot 144 and insert it. Then rotate the high-pressure chamber 12 so that the buckle 141 enters the gap between the first retaining ring 142 and the second retaining ring 143, thereby locking the high-pressure chamber 12 to the high-pressure chamber base 11. This rotating locking mechanism 14 enables quick installation and removal of the high-pressure chamber 12, facilitating operation and cleaning.

[0050] It should be noted that the number of buckles 141 and slots 144 in this embodiment is not limited to the above description. Those skilled in the art can flexibly set one or more buckles 141 and matching slots 144 according to the actual requirements of the size of the high-pressure chamber 12 and the high-pressure chamber base 11 and the connection stability. For example, when the diameter of the high-pressure chamber 12 is large, multiple buckles 141 can be evenly arranged circumferentially to achieve a more balanced distribution of locking force.

[0051] refer to Figure 3 The printing mechanism 3 specifically includes a printing stage 31, a printing platform 32, and a lifting and adjusting assembly 33. The printing stage 31 is fixedly installed inside the high-pressure chamber 12 and connected to the high-pressure chamber cover 13 via a printing connecting rod 34. The upper end of the printing connecting rod 34 is fixedly connected to the high-pressure chamber cover 13, and the lower end is fixedly connected to the printing stage 31, thus suspending the printing stage 31 within the high-pressure chamber 12. A vertical printing channel 35 is provided on the printing stage 31, and the printing platform 32 is disposed within the printing channel 35 and slides against the inner wall of the printing channel 35. The lifting and adjusting assembly 33 is connected to the printing platform 32 and is used to adjust the height of the printing platform 32. When the printing platform 32 descends, a recess of a certain height is formed between its top and the upper surface of the printing channel 35, which is used to accommodate the powder layer laid by the powder spreading mechanism 4.

[0052] refer to Figure 4The lifting and adjusting assembly 33 specifically includes a lifting platform 331 and at least one lifting rod 332. The lifting platform 331 is located below the printing stage 31, and the printing platform 32 is fixedly installed on the upper surface of the lifting platform 331. The lower end of the lifting rod 332 is fixedly connected to the lifting platform 331, and the upper end of the lifting rod 332 passes through the printing stage 31 and the high-pressure chamber cover 13 before extending outside the high-pressure chamber 1. A scale 333 is threadedly connected to the extended end of the lifting rod 332. The outer circumference of the scale 333 is marked with graduations. During operation, rotating the scale 333 causes the lifting rod 332 to move the lifting platform 331 and the printing platform 32 up and down due to the threaded engagement. By reading the rotation angle or number of rotations of the scale 333, the descent height of the printing platform 32 can be precisely controlled, thereby controlling the thickness of each layer of powder.

[0053] It should be noted that the number of lifting rods 332 is not strictly limited in this embodiment. Preferably, two lifting rods 332 are used, and the two lifting rods 332 are symmetrically arranged on both sides of the lifting platform 331. This symmetrical double-rod layout helps to disperse the lifting force, prevents the lifting platform 331 from deflecting during lifting, and ensures that the printing platform 32 remains horizontal, thereby guaranteeing the uniformity of the powder thickness for each layer.

[0054] refer to Figure 5 The powder spreading mechanism 4 specifically includes a powder storage bin 41 and a powder spreading connecting rod 42. The powder storage bin 41 is located on the upper surface of the printing stage 31, and a powder spreading channel 43 is provided on the powder storage bin 41. The powder spreading channel 43 contains the metal powder to be printed. The lower end of the powder spreading connecting rod 42 is fixedly connected to the powder storage bin 41, and the upper end of the powder spreading connecting rod 42 passes through the high-pressure chamber cover 13 and is movably connected to it. The top end of the powder spreading connecting rod 42 protrudes from the surface of the high-pressure chamber cover 13 to facilitate manual or mechanical rotation. When powder spreading is required, the powder spreading connecting rod 42 is rotated, causing the powder storage bin 41 to rotate around the central axis of the printing stage 31. When the powder spreading channel 43 rotates above the printing channel 35, the powder in the powder spreading channel 43 falls into the recess between the printing platform 32 and the printing channel 35 under the action of gravity, thereby completing the spreading of a layer of powder.

[0055] refer to Figure 6 In this embodiment, a flange 15 is also provided inside the high-pressure chamber 12. The flange 15 is fixed to the upper part of the inner wall of the high-pressure chamber 12 and is used to install the light-transmitting element 2. Specifically, the light-transmitting element 2 is disposed between the flange 15 and the high-pressure chamber cover 13. The high-pressure chamber cover 13 has a light-transmitting channel 16 corresponding to the position of the light-transmitting element 2. The laser beam passes through the light-transmitting channel 16 and the light-transmitting element 2 from the outside and enters the interior of the high-pressure chamber 12, irradiating the powder layer on the printing platform 32 to achieve selective melting.

[0056] It should be noted that, in this embodiment, the light-transmitting element 2 is preferably a plane lens. Plane lenses have advantages such as low processing cost, small optical path distortion, and easy sealing installation, which can ensure that the laser beam maintains good beam quality when passing through the high-pressure chamber 1. Provided that the light transmission and pressure resistance requirements are met, the light-transmitting element 2 can also adopt other forms of optical elements, such as quartz windows.

[0057] To ensure the airtightness of the high-pressure chamber 1, this embodiment also includes multiple sealing structures. Specifically, a first sealing ring 6 is provided between the light-transmitting element 2 and the high-pressure chamber cover 13, and between the light-transmitting element 2 and the flange 15; a second sealing ring 7 is provided between the high-pressure chamber cover 13 and the high-pressure chamber body 12; a third sealing ring 8 is provided between the high-pressure chamber body 12 and the high-pressure chamber base 11; and a fourth sealing ring 9 is provided between the high-pressure chamber base 11 and the printer substrate 100. These sealing rings are preferably made of fluororubber or metal and are resistant to high pressure and high temperature to ensure that no leakage occurs during pressurization.

[0058] refer to Figure 7 The pressure regulating mechanism 5 includes an inlet pipe 51, an outlet pipe 52, and a pressure relief valve 53. One end of the inlet pipe 51 is connected to an external compressed gas cylinder containing inert gases such as argon or nitrogen. The other end of the inlet pipe 51 is connected to the upper part of the side wall of the high-pressure chamber 1 for introducing gas into the high-pressure chamber 1. The outlet pipe 52 is connected to the lower part of the side wall of the high-pressure chamber 1 for discharging gas from inside the high-pressure chamber 1. The pressure relief valve 53 is installed on the outlet pipe 52 for regulating the outlet flow rate.

[0059] In use, the valve of the compressed gas cylinder is opened, and inert gas enters the high-pressure chamber 1 through the inlet pipe 51. By adjusting the opening of the pressure relief valve 53, the exhaust flow rate of the outlet pipe 52 is controlled, making the inlet flow rate greater than the outlet flow rate, thereby creating a positive pressure environment inside the high-pressure chamber 1 and gradually increasing the chamber pressure. By controlling the inlet airflow rate in conjunction with the opening of the pressure relief valve 53, the pressure inside the high-pressure chamber 1 can be stabilized at a preset value. The high-pressure environment can effectively increase the boiling point of the metal powder and inhibit the evaporation and burn-off of volatile elements.

[0060] Meanwhile, the gas discharged from the exhaust pipe 52 can carry away the smoke and metal vapor generated in the high-pressure chamber 1 during the printing process, reducing the accumulation of smoke in the chamber and thus reducing the obstruction of the laser path and the impact on printing quality.

[0061] Preferably, a filter (not shown in the figure) may also be installed on the exhaust pipe 52 to filter the exhaust gas and remove soot particles and metal vapors to meet gas emission standards or facilitate subsequent gas recycling.

[0062] It should be noted that when the gas pressure of the compressed gas cylinder itself cannot meet the pressurization requirements of the high-pressure chamber 1, a booster pump (not shown in the figure) can be added at the air inlet pipe 51. The booster pump can pressurize the inert gas to the required pressure before it is introduced into the high-pressure chamber 1, thereby meeting the printing requirements of higher pressure levels.

[0063] Through the aforementioned pressure regulating mechanism 5, this device can flexibly and stably control the air pressure inside the high-pressure chamber 1, providing a reliable environmental guarantee for high-quality printing of volatile metal materials.

[0064] The working process of the pressure printing device in this embodiment is as follows:

[0065] First, the high-pressure chamber base 11 is fixedly mounted on the printer base plate 100 of the laser powder bed melting equipment. The high-pressure chamber body 12 is locked to the high-pressure chamber base 11 by rotating the locking mechanism 14. Printing powder is loaded into the powder storage hopper 41. The dial 333 is rotated to raise the printing platform 32 to the initial position flush with the upper surface of the printing stage 31.

[0066] Then, inert gas is introduced into the high-pressure chamber 1 through the pressure regulating mechanism 5, air is discharged, and the pressure inside the chamber is increased to the preset printing pressure. Under this pressure, the boiling point of the metallic material is significantly increased.

[0067] Next, printing begins layer by layer. Rotating the powder-spreading connecting rod 42 causes the powder-spreading channel 43 of the powder storage chamber 41 to rotate above the printing channel 35, allowing powder to fall into the recess between the printing platform 32 and the printing channel 35, forming a uniform powder layer. The laser beam shines through the light-transmitting element 2 onto the powder layer, selectively melting the powder according to a preset scanning path. After completing one layer, rotating the scale 333 causes the printing platform 32 to precisely descend by the height of one layer thickness. The powder-spreading and laser melting steps are then repeated until the entire three-dimensional part is printed.

[0068] After printing is completed, the pressure inside the high-pressure chamber 1 is slowly reduced to atmospheric pressure through the pressure relief valve 53. Then, the high-pressure chamber 12 is disassembled and the printed parts are taken out.

[0069] This embodiment, through the above-described device and method, enables printing under high pressure without modifying the original laser powder bed melting equipment host, effectively suppressing component loss and porosity defects of volatile metal materials, and improving the density and mechanical properties of the formed parts.

[0070] It should be stated that the above-described specific embodiments are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art should understand that various modifications, equivalent substitutions, and variations can be made to the present invention. However, such variations, as long as they do not depart from the spirit of the present invention, should be within the scope of protection of the present invention. Furthermore, some terminology used in this specification and claims is not limiting, but merely for ease of description.

Claims

1. A pressure printing apparatus for laser additive manufacturing, characterized in that, include: A high-pressure chamber (1) is detachably mounted on the printer base plate (100) of a laser powder bed melting device, forming a sealed printing space. The high-pressure chamber (1) includes a high-pressure chamber base (11), a high-pressure chamber body (12), and a high-pressure chamber cover (13). The high-pressure chamber body (12) and the high-pressure chamber base (11) are detachably connected by a rotating locking mechanism (14). The high-pressure chamber cover (13) is mounted on the high-pressure chamber body (12), so that the interior of the high-pressure chamber body (12) forms a sealed container. The rotating locking mechanism (14) includes a protrusion and a recess. The protrusion is located on the outer side wall of the high-pressure chamber body (12), and the recess is located on the inner side wall of the high-pressure chamber base (11). When the protrusion and the recess are aligned, the high-pressure chamber body (12) can be placed into the high-pressure chamber base (11) and fixed by rotating locking. A light-transmitting element (2) is disposed on the high-pressure chamber (1) for allowing laser light to pass through and enter the interior of the high-pressure chamber (1); The printing mechanism (3) is located inside the high-pressure chamber (1) and is used to carry powder and form a printing layer. The printing mechanism (3) includes a printing stage (31), a printing platform (32) and a lifting adjustment component (33). The printing stage (31) is located inside the high-pressure chamber (12) and is connected to the upper cover (13) of the high-pressure chamber via a printing connecting rod (34). A printing channel (35) is provided on the printing stage (31). The printing platform (32) is located inside the printing channel (35) and is slidably connected to it. The lifting adjustment component (33) is connected to the printing platform (32) and is used to adjust the height of the printing platform (32) so that a height difference is formed between the printing platform (32) and the upper surface of the printing channel (35) so that powder is laid layer by layer on the printing platform (32). Powder spreading mechanism (4), which is disposed on the printing mechanism (3) and is used to spread powder layer by layer; Pressure regulating mechanism (5), which is connected to the high-pressure chamber (1) and is used to regulate the air pressure inside the high-pressure chamber (1); The powder spreading mechanism (4) includes a powder storage bin (41) and a powder spreading connecting rod (42). The powder storage bin (41) is located inside the high-pressure chamber (1) and is set on the printing stage (31). One end of the powder spreading connecting rod (42) is connected to the powder storage bin (41), and the other end is movably connected to the top cover (13) of the high-pressure chamber and protrudes from its surface. A powder spreading channel (43) is provided on the powder storage bin (41). When the powder spreading connecting rod (42) drives the powder storage bin (41) to rotate until the powder spreading channel (43) coincides with the printing channel (35), the powder in the powder storage bin (41) will fall into the printing channel (35) through the powder spreading channel (43) to spread the powder.

2. The pressure printing apparatus for laser additive manufacturing according to claim 1, characterized in that, The protrusion includes at least two buckles (141), which are radially spaced along the high-pressure chamber body (12). The recess includes a first retaining ring (142) and a second retaining ring (143), which are axially spaced along the high-pressure chamber base (11). The first retaining ring (142) has at least two slots (144) along its circumferential direction. The slots (144) match the shape of the buckles (141). The buckles (141) can pass through the slots (144) and rotate to engage and fix with the first retaining ring (142) and the second retaining ring (143).

3. The pressure printing apparatus for laser additive manufacturing according to claim 1, characterized in that, The lifting adjustment assembly (33) includes a lifting platform (331) and at least one lifting rod (332). The lifting platform (331) is located below the printing platform (31). The printing platform (32) is installed on the lifting platform (331). One end of the lifting rod (332) is connected to the lifting platform (331), and the other end passes through the high-pressure chamber cover (13) and is threadedly connected to a dial (333). The dial (333) rotates to drive the lifting rod (332) to move up and down.

4. The pressure printing apparatus for laser additive manufacturing according to claim 1, characterized in that, The high-pressure chamber (12) is provided with a flange (15), and the light-transmitting element (2) is provided between the flange (15) and the high-pressure chamber cover (13). The high-pressure chamber cover (13) is provided with a light-transmitting channel (16) corresponding to the position of the light-transmitting element (2) so that the laser can pass through.

5. The pressure printing apparatus for laser additive manufacturing according to claim 4, characterized in that, A first sealing ring (6) is provided between the light-transmitting element (2), the high-pressure chamber cover (13), and the flange (15). A second sealing ring (7) is provided between the high-pressure chamber cover (13) and the high-pressure chamber body (12). A third sealing ring (8) is provided between the high-pressure chamber body (12) and the high-pressure chamber base (11). A fourth sealing ring (9) is provided between the high-pressure chamber base (11) and the printer substrate (100).

6. The pressure printing apparatus for laser additive manufacturing according to any one of claims 1-5, characterized in that, The pressure regulating mechanism (5) includes an air inlet pipe (51), an air outlet pipe (52), and a pressure relief valve (53). One end of the air inlet pipe (51) is connected to an external compressed air cylinder, and the other end is connected to the upper part of the side wall of the high-pressure chamber (1). The air outlet pipe (52) is connected to the lower part of the side wall of the high-pressure chamber (1), and the pressure relief valve (53) is installed on the air outlet pipe (52).

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