A powder spreading system and method for multi-material additive manufacturing

Abstract

The present application belongs to the technical field of metal additive manufacturing, and discloses a powder laying system for multi-material additive manufacturing, which comprises a powder feeding device, a powder storage cabin and a powder laying device; the powder feeding device comprises a powder feeding gas path, a powder supply port and a rotary powder changing arm, the powder supply port is used for adding printing powder, the first end of the rotary powder changing arm is rotatably connected to the powder feeding gas path and communicates with the powder feeding gas path, and the second end of the rotary powder changing arm is provided with the powder supply port; the internal space of the powder storage cabin is circumferentially divided into a plurality of mutually independent sub-cabins, each sub-cabin is provided at the upper end with a powder inlet port matched with the powder supply port, the powder supply port is connected to different powder inlet ports through rotation to feed and store powder in different sub-cabins, and each sub-cabin is provided at the lower end with a cabin door, the opening and closing of the cabin door controls the falling of printing powder in the corresponding sub-cabin to the powder laying device, so that the printing powder of different compositions is stored in different zones before processing and is separated and falls during processing, the operation process of the staff is simplified, and the applicability of the powder laying type additive manufacturing in the multi-material application scene is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal additive manufacturing, and more particularly relates to a powder laying system and a powder laying method for multi-material additive manufacturing. BACKGROUND

[0002] Metal additive manufacturing technology is an important branch of additive manufacturing. The basic principle of additive manufacturing is used, that is, a three-dimensional model of a part is designed by a computer first, then the three-dimensional model is sliced and layered by special software to obtain cross-section profile data, then the profile data is imported into a rapid prototyping device, and the device controls the laser beam to selectively melt the metal powder of each layer to gradually stack a three-dimensional metal part. Compared with other traditional precision machining technologies, the technology has the advantages of being able to directly manufacture metal parts with high precision, complex geometric structure, dense structure, and good mechanical properties. The advantage of metal additive manufacturing technology is that it can directly manufacture metal parts with high precision, lightweight, complex geometric structure, dense structure, and good mechanical properties.

[0003] At present, metal additive manufacturing technology can be divided into powder feeding type and powder laying type according to the feeding mode of metal powder, among which the powder feeding type is faster in forming speed, but the precision of the obtained parts is far inferior to that of the powder laying type. Therefore, the powder laying type metal additive manufacturing has great advantages in preparing high-precision complex precision parts, such as laser selective melting technology which has achieved good application in the fields of medicine and automobiles. However, the powder laying type additive manufacturing equipment generally needs to print one kind of powder and then replace another kind of powder during the processing, which has the defect of complicated powder replacement steps during processing, which makes most of the powder laying type additive manufacturing parts prepared by a single powder material. With the increase of application scenarios and the improvement of performance requirements, it is difficult for traditional powder laying type additive manufacturing equipment to prepare diversified parts with different compositions.

[0004] Therefore, in order to improve the applicability of powder laying type additive manufacturing in multi-material application scenarios, it is urgent to develop a new powder laying system for additive manufacturing to solve the problems of difficulty in replacing powder during processing and complicated manual operation of the existing powder laying system for multi-material additive manufacturing. SUMMARY

[0005] In view of the problems of difficulty in replacing powder during processing and complicated manual operation of the existing multi-material additive manufacturing powder laying system, the present application provides a powder laying system and a powder laying method for multi-material additive manufacturing, which aims to realize the pre-divisional storage of printing powders with different compositions, the separate powder falling during processing, simplify the operation process of the workers, and improve the applicability of powder laying type additive manufacturing in multi-material application scenarios by setting a rotatable rotating powder replacement arm and an opening and closing controllable hatch.

[0006] To achieve the above object, according to one aspect of the present application, a powder laying system for multi-material additive manufacturing is provided, which comprises, from top to bottom, a powder feeding device, a powder storage cabin and a powder laying device; the powder feeding device comprises a powder feeding gas path, a powder supply port and a rotating powder changing arm arranged in sequence on the powder feeding gas path, the powder supply port is used for adding printing powder, the first end of the rotating powder changing arm is rotatably connected to the powder feeding gas path and communicates with the powder feeding gas path, and the second end of the rotating powder changing arm is provided with a powder feeding port; the internal space of the powder storage cabin is circumferentially divided into a plurality of independent sub-cabins, the upper end of each sub-cabin is provided with a powder inlet port matched with the powder supply port, the powder supply port is connected to different powder inlet ports by rotation to feed different sub-cabins for powder storage, and the lower end of each sub-cabin is provided with a cabin door, and the opening and closing control of the cabin door controls the falling of printing powder in the sub-cabin to the powder laying device for powder laying printing.

[0007] Preferably, the powder storage cabin is a hollow inverted conical structure, the powder laying system further comprises a powder falling gas path, the powder falling gas path passes through the central axis of the powder storage cabin, a partition plate is fixedly connected between the pipe wall of the powder falling gas path and the outer wall of the powder storage cabin, and the partition plate divides the internal space of the powder storage cabin into a plurality of independent sub-cabins, and the opening and closing control of each cabin door controls the communication and isolation between the sub-cabin and the powder falling gas path.

[0008] Preferably, there is a gap between the bottom end of the pipe wall of the powder falling gas path and the bottom end of the powder storage cabin, so that the powder falling gas path and the lower end of each sub-cabin have an opening, or the pipe wall of the powder falling gas path is respectively provided with an opening at the lower end of each sub-cabin.

[0009] The cabin door is arranged between two adjacent partition plates at the opening and can slide up and down along the outer wall of the powder falling gas path, the cabin door has a first position above and a second position below relative to the powder storage cabin, in the first position, the cabin door is above the opening, and the opening allows the sub-cabin to communicate with the powder falling gas path, and in the second position, the cabin door is at the opening to isolate the sub-cabin from the powder falling gas path.

[0010] Preferably, the powder laying system further comprises a powder leveling assembly, the powder leveling assembly comprises a connecting section and a powder leveling section, the upper end of the connecting section is connected to the powder storage cabin and the connecting section communicates with the powder falling gas path, the lower end of the connecting section is connected to the powder leveling section, the powder leveling section is a flat plate-shaped hollow structure with a plurality of small holes uniformly distributed on the bottom surface, and the connecting section is provided with a powder flow meter and an opening-adjustable pressure limiting valve.

[0011] Preferably, the powder spreading device comprises a doctor blade and a forming substrate, the forming substrate is located directly below the powder leveling assembly, the doctor blade is arranged above the forming substrate and can slide horizontally, and the doctor blade is used to spread the printing powder falling from the small holes to the forming substrate.

[0012] Preferably, the rotating powder changing arm further comprises a main section and a telescopic section, the main section and the telescopic section are both tubular structures, the inner diameter of the main section is larger than the outer diameter of the telescopic section, the main section is fixedly connected to the second end of the rotating powder changing arm and faces the powder inlet, the telescopic section is coaxially arranged with the main section, the telescopic section is slidably connected to the main section, the lower end of the telescopic section forms the powder outlet, and the telescopic section slides up and down to drive the powder outlet to rise and fall.

[0013] Preferably, the upper end surface of each of the sub-chambers is provided with a protruding part, the powder inlet is arranged on the protruding part, the periphery of the powder outlet is provided with a sealing cover, the sealing cover matches the shape of the protruding part, and the sealing cover is sealingly connected to the corresponding protruding part when the powder outlet is in communication with any of the powder inlets.

[0014] Preferably, the interior of each of the sub-chambers is provided with a spiral stirring rod, the spiral stirring rod comprises a rotating shaft and a spiral blade inclinedly wrapped outside the rotating shaft, the rotating shaft is fixedly connected to the spiral blade, the spiral stirring rod is connected to an external motor, and the external motor controls the spiral stirring rod to rotate around the rotating shaft.

[0015] And / or, the inner wall of each of the sub-chambers is provided with a heating plate.

[0016] According to another aspect of the present application, a powder spreading method for multi-material additive manufacturing is provided, and the specific steps are as follows:

[0017] Step 1: Preparing multiple materials required for additive manufacturing and forming multiple different printing powders;

[0018] Step 2: Adding a first printing powder to the powder supply port;

[0019] Step 3: Controlling the rotation angle of the rotating powder changing arm to be above one of the powder inlets, introducing inert gas into the powder conveying gas path, adjusting the gas pressure, and making the first printing powder flow into the corresponding sub-chamber through the powder conveying gas path, the rotating powder changing arm, the powder outlet, and the powder inlet;

[0020] Step 4: When the storage amount of the first printing powder reaches the preset requirement, stop introducing the inert gas;

[0021] Step 5: Sequentially repeating the operations of steps 2 to 4 until each printing powder is stored in the corresponding sub-chamber.

[0022] Step 6: according to the printing powder required by each layer of the additive manufacturing process, the hatch door of the cabin storing the corresponding printing powder is controlled to open, so that the printing powder falls to the powder laying device;

[0023] Step 7: after the printing powder required by each layer flows out of the hatch door, the corresponding hatch door is closed.

[0024] Preferably, the materials in the plurality of different printing powders are the same, the proportions of different materials change in a gradient, and the plurality of printing powders are sequentially laid and printed to form a gradient material additive manufacturing.

[0025] Overall, compared with the prior art, the above technical solutions conceived by the present application have the following technical effects:

[0026] 1. A powder laying system for multi-material additive manufacturing is provided, which can add printing powders of different compositions to each cabin before printing by arranging the internal space of the powder storage cabin to be circumferentially divided into a plurality of independent sub-cabins, and by rotating the rotating powder changing arm connected to the powder inlet of each sub-cabin at different angles. By arranging a hatch door for each sub-cabin, the hatch door of the corresponding sub-cabin can be opened as needed during the printing process, thereby realizing the pre-processing storage and processing flow separation of printing powders of different compositions, simplifying the operation process of the staff, and improving the applicability of powder laying type additive manufacturing in multi-material application scenarios.

[0027] 2. The present application arranges the powder storage cabin to be a hollow inverted conical structure, so that the printing powder in the sub-cabin is more easily moved downward under the action of gravity. The powder falling air path is arranged to pass through the central axis of the powder storage cabin, so that when the hatch door is opened, the printing powder in the corresponding sub-cabin enters the powder falling air path under the action of gravity and the turbulent flow of the powder falling air path, which is conducive to the uniform dispersion of the printing powder.

[0028] 3. The present application further provides a powder leveling assembly, which is connected to the powder falling air path through a connecting section, and a powder flow meter and an opening adjustable pressure limiting valve are arranged on the connecting section, so as to control the amount of printing powder falling into the powder laying device. The powder leveling section is arranged as a flat plate hollow structure with a plurality of small holes uniformly distributed on the bottom surface, so that the printing powder entering the powder leveling assembly through the powder falling air path is further uniformly dispersed, which is conducive to improving the uniformity and flatness of the printing powder falling into the powder laying device, thereby improving the printing quality.

[0029] 4. The present application designs a protruding part on the upper end of the sub-cabin and a sealing cover around the powder feeding port, so that when the powder feeding port is connected to any powder inlet, the protruding part and the sealing cover are in sealing contact to avoid loss or contamination of the printing powder when entering the sub-cabin.

[0030] 5. The present application is characterized in that a spiral stirring rod is arranged inside the sub-tank, an external motor is arranged to control the rotation of the spiral stirring rod around the rotating shaft, so that the spiral blade inclined around the outside of the rotating shaft stirs the printing powder in the sub-tank, avoids the adhesion or clumping of the printing powder, and causes the decrease of the flowability, and a heating plate is arranged on the inner wall of the sub-tank to heat the printing powder to keep it dry to further improve the flowability and improve the printing quality.

[0031] 6. The present application provides a powder laying method for multi-material additive manufacturing, which can realize gradient material additive manufacturing by preparing a plurality of different printing powders with the same material type and gradient ratio of each material, storing and distributing the plurality of printing powders, and sequentially laying and printing to realize gradient material additive manufacturing, and has wide application scenarios in the field of gradient material preparation. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a whole schematic diagram of a powder laying system for multi-material additive manufacturing provided by an embodiment of the present application;

[0033] Figure 2 is a structural schematic diagram of a powder storage tank provided by an embodiment of the present application;

[0034] Figure 3 is a structural schematic diagram of a powder falling air path and a hatch provided by an embodiment of the present application;

[0035] Figure 4 is a structural schematic diagram of a spiral stirring rod provided by an embodiment of the present application;

[0036] Figure 5 is a structural schematic diagram of a rotating powder changing arm provided by an embodiment of the present application;

[0037] In all the drawings, the same reference signs are used to represent the same elements or structures, wherein:

[0038] 1-powder storage tank, 2-rotating powder changing arm, 3-powder falling air path, 4-powder laying section, 5-scraper, 6-shaped base plate, 7-powder supply port, 8-powder feeding air path, 9-sealing cover, 10-first high-pressure gas cylinder, 11-connection section, 12-second high-pressure gas cylinder, 13-first air path valve, 14-second air path valve, 15-cavity, 16-pressure limiting valve, 17-powder inlet, 18-spiral stirring rod, 19-sub-tank, 20-protruding part, 21-hatch, 181-rotating shaft, 182-spiral blade, 201-main joint, 202-first telescopic joint, 203-second telescopic joint, 204-third telescopic joint. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application and not to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0040] The technical solutions of the present application will be described in detail below with specific embodiments.

[0041] Please refer to Figure 1 , the embodiment provides a powder laying system for multi-material additive manufacturing, which comprises a powder feeding device, a powder storage cabin 1 and a powder laying device from top to bottom. The powder feeding device comprises a powder feeding gas path 8 and a powder supply port 7 and a rotating powder changing arm 2 arranged on the powder feeding gas path 8 in sequence. The powder supply port 7 is used to add printing powder, and the first end of the rotating powder changing arm 2 is circumferentially rotatably connected to the powder feeding gas path 8 and communicates with the powder feeding gas path 8. The second end of the rotating powder changing arm 2 is provided with a powder feeding port. The internal space of the powder storage cabin 1 is circumferentially divided into a plurality of independent sub-cabin 19, as shown in Figure 2 , the upper end of each sub-cabin 19 is provided with a powder inlet port 17 matched with the powder supply port. The powder supply port rotates circumferentially around the first end through the rotating powder changing arm 2 to connect with different powder inlet ports 17 to feed different sub-cabin 19 for storage. The lower end of each sub-cabin 19 is provided with a cabin door 21, and the opening and closing of the cabin door 21 controls the falling of the printing powder in the sub-cabin 19 to the powder laying device for powder laying printing.

[0042] Specifically, the upper end of each sub-cabin 19 is provided with a pressure stabilizing hole, which is covered by a mesh surface or a film. The pressure stabilizing hole allows gas to flow through and limits solid powder from passing through, thereby balancing the pressure in each sub-cabin 19 while preventing the leakage of printing powder. The upper part of the powder supply port 7 is provided with a sealing cover, and the lower part is provided with a cavity 15 communicating with the powder feeding gas path 8. The prepared printing powder is added to the powder supply port 7 and temporarily stored in the cavity 15. When inert gas is introduced, it drives the printing powder in the cavity 15 into the powder feeding gas path 8. The powder feeding gas path 8 can also be directly provided as an opening on the powder feeding gas path 8, or other structures matched with the device for adding printing powder, which are not limited herein. The front end of the powder feeding gas path 8 is connected to a first high-pressure gas cylinder 10, and the first high-pressure gas cylinder 10 is provided with a first gas path valve 13. By controlling the opening and closing of the first gas path valve 13, the first high-pressure gas cylinder 10 provides high-pressure inert gas to transport the printing powder. The powder feeding gas path 8 can also be directly connected to other structures capable of providing high-pressure gas source, which are not limited herein. The inert gas uses argon, and other inert gases can also be used, which are not limited herein.

[0043] In the printing before the sub-division powder storage link, the prepared printing powder is added to the powder feeding gas path 8 through the powder supply port 7, and after adding enough printing powder of this type, the powder supply port 7 is sealed, the rotating powder changing arm 2 is controlled to rotate to make the powder supply port communicate with the powder inlet port 17 of the sub-division 19 storing the printing powder, at this time, high pressure inert gas is introduced into the powder feeding gas path 8, so that the printing powder in the powder feeding gas path 8 falls into the corresponding sub-division 19 under the action of gas pressure through the rotating powder changing arm 2. According to the number of different types of printing powder required by additive manufacturing, the above process is repeated until each type of printing powder is stored in different sub-divisions 19, so as to realize the pre-processing of different component printing powder in different sub-divisions.

[0044] Specifically, the powder storage cabin 1 is a hollow inverted conical structure, so that the printing powder in the sub-division 19 is more easily moved downward under the action of gravity. The powder laying system further comprises a powder falling gas path 3 which passes through the center axis of the powder storage cabin 1, and eight uniformly distributed partitions are fixedly connected between the pipe wall of the powder falling gas path 3 and the outer wall of the powder storage cabin 1, which divides the internal space of the powder storage cabin 1 into eight independent sub-divisions 19. The opening and closing of each cabin door 21 controls the communication and isolation of the corresponding sub-division 19 and the powder falling gas path 3. The front end of the powder falling gas path 3 is connected with the second high pressure gas cylinder 12, and the second gas path valve 14 is arranged on the second high pressure gas cylinder 12. The second high pressure gas cylinder 12 provides high pressure inert gas to the powder falling gas path 3 by controlling the opening and closing of the second gas path valve 14; the powder feeding gas path 8 can also be directly connected with other structures capable of providing high pressure gas source, which is not limited here. The inert gas uses argon, and other inert gases can also be used, which is not limited here.

[0045] In the powder falling link, the cabin door 21 of the corresponding sub-division 19 is opened according to the required printing powder during processing, and high pressure inert gas is introduced into the powder falling gas path 3, so that the printing powder in the corresponding sub-division 19 enters the powder falling gas path 3 under the action of gravity and the turbulent flow of the powder falling gas path 3, which is beneficial to make the printing powder be scattered uniformly.

[0046] Specifically, as Figure 3As shown, there is a gap between the bottom end of the tube wall of the powder falling air path 3 and the bottom end of the powder storage cabin 1, so that there is an opening between the powder falling air path 3 and the lower end of each of the sub-cabin 19, or the tube wall of the powder falling air path 3 is respectively provided with an opening at the lower end of each of the sub-cabin 19. The cabin door 21 is arranged at the opening between the adjacent two partitions and can slide up and down along the outer wall of the powder falling air path 3. The cabin door 21 has a first position above and a second position below relative to the powder storage cabin 1. When the cabin door 21 is in the first position, the cabin door 21 is above the opening, and the opening allows the sub-cabin 19 to communicate with the powder falling air path 3. When the cabin door 21 is in the second position, the cabin door 21 is at the opening, so that the sub-cabin 19 is cut off from the powder falling air path 3. The opening and closing of the cabin door 21 is controlled by a pneumatic transmission structure or remotely controlled by an electric control, which is not limited here.

[0047] As a further preferred embodiment, the powder laying system further comprises a powder leveling assembly, which comprises a connecting section 11 and a powder leveling section 4. The upper end of the connecting section 11 is connected to the powder storage cabin 1, and the connecting section 11 communicates with the powder falling air path 3. The connecting section 11 is provided with a powder flow meter and an opening-adjustable pressure limiting valve 16. The opening of the pressure limiting valve 16 is adjusted according to the powder flow meter, so as to control the flow of printing powder falling into the powder laying device. After the printing powder falls completely, the pressure limiting valve 16 is closed to stop the air supply of the powder falling air path 3, so as to prevent the printing powder from scattering to the area outside the powder laying device and causing blockage. The lower end of the connecting section 11 is connected to the powder leveling section 4. The powder leveling section 4 is a flat plate-shaped hollow structure, and the bottom surface is uniformly distributed with a plurality of small holes. The printing powder enters the powder leveling assembly through the powder falling air path 3 and is further scattered and leveled, which is beneficial to improve the uniformity and flatness of the printing powder falling into the powder laying device, so as to improve the printing quality.

[0048] Specifically, the powder laying device comprises a scraper 5 and a forming substrate 6. The forming substrate 6 is located directly below the powder leveling assembly. The scraper 5 is arranged above the forming substrate 6 and can slide in the horizontal direction. The scraper 5 is used to lay the printing powder falling onto the forming substrate 6 from the small holes.

[0049] As a further preferred embodiment, as Figure 5As shown, the rotating powder changing arm 2 further comprises a main section 201 and a telescopic section, both of which are tubular structures, the main section 201 is fixedly connected to the second end of the rotating powder changing arm 2 and faces the powder inlet port 17, and the telescopic section is coaxially arranged with the main section 201, the inner diameter of the main section 201 is greater than the outer diameter of the telescopic section, and the lower end of the telescopic section forms the powder outlet port. The telescopic section is slidably connected to the main section 201, including a retracted state of sliding upward into the main section 201 and an extended state of sliding downward, the telescopic section is in the retracted state when the rotating powder changing arm 2 rotates (as shown in b and c of Figure 5 ), and is in the extended state when the powder outlet port and the powder outlet port are communicated (as shown in a and b of Figure 5 ), thereby avoiding the positional interference between the rotating powder changing arm 2 and the powder storage cabin 1, and facilitating the docking of the powder outlet port and the powder outlet port.

[0050] Specifically, the telescopic section can be designed as multiple layers, such as including a first telescopic section 202, a second telescopic section 203 and a third telescopic section 204, the inner diameter of the main section 201 is greater than the outer diameter of the first telescopic section 202, the inner diameter of the first telescopic section 202 is greater than the outer diameter of the second telescopic section 203, the inner diameter of the second telescopic section 203 is greater than the outer diameter of the third telescopic section 204, and the lower end of the third telescopic section 204 forms the powder outlet port.

[0051] Specifically, the upper end surface of each of the sub-cabin 19 is provided with a protruding part 20, the powder inlet port 17 is arranged on the protruding part 20, the periphery of the powder outlet port is provided with a sealing cover 9, the sealing cover 9 matches the shape of the protruding part 20, and the sealing cover 9 is sealingly connected with the corresponding protruding part 20 at the position where the powder outlet port is communicated with any of the powder inlet ports 17, so as to avoid the loss or pollution of the printing powder when entering the sub-cabin 19.

[0052] As a further preferred embodiment, as shown in Figure 4 , the interior of each of the sub-cabin 19 is provided with a spiral stirring rod 18, the spiral stirring rod 18 comprises a rotating shaft 181 and a spiral blade 182 inclinedly wrapped outside the rotating shaft 181, the rotating shaft 181 is fixedly connected with the spiral blade 182, the spiral stirring rod 18 is connected with an external motor, the external motor controls the spiral stirring rod 18 to rotate around the rotating shaft 181, so that the spiral blade 182 stirs the printing powder in each sub-cabin 19, thereby avoiding the decrease of fluidity caused by the adhesion or clumping of the printing powder; and / or, the inner wall of each of the sub-cabin 19 is provided with a heating plate, the heating of the printing powder keeps it dry to further improve the fluidity and improve the printing quality.

[0053] According to another aspect of the present application, a powder laying method for multi-material additive manufacturing is provided, and the specific steps are as follows:

[0054] Step 1: Preparing multiple materials required for additive manufacturing and forming multiple different printing powders;

[0055] Step 2: Adding the first printing powder into the powder supply port 7;

[0056] Step 3: Controlling the rotation angle of the rotating powder conversion arm 2 to be above the powder inlet port 17, introducing inert gas into the powder feeding gas path 8, adjusting the gas pressure, and allowing the first printing powder to flow into the corresponding compartment 19 through the powder feeding gas path 8, the rotating powder conversion arm 2, the powder feeding port, and the powder inlet port 17;

[0057] Step 4: When the storage amount of the first printing powder reaches the preset requirement, stop introducing inert gas;

[0058] Step 5: Repeating the operations of steps 2-4 in sequence until each printing powder is stored in the corresponding compartment 19;

[0059] Step 6: According to the printing powder required for each layer of the additive manufacturing process, control the opening of the hatch 21 of the compartment 19 storing the corresponding printing powder to allow the printing powder to fall to the powder spreading device;

[0060] Step 7: After the required printing powder for each layer flows out of the hatch 21, close the corresponding hatch 21.

[0061] Preferably, the materials in the multiple different printing powders are the same, and the proportions of different materials change in a gradient. The multiple printing powders are sequentially spread and printed to form a gradient material additive manufacturing.

[0062] Based on this, the powder spreading system and method for multi-material additive manufacturing are further described by taking Ti6Al4V-AlMgScZr composition gradient material additive manufacturing as an example. The example includes the following steps:

[0063] S1: Preparing 8 different compositions of 25-53 μm particle size 3D printing special metal spherical powder required for printing, with mass fractions of 100% Ti6Al4V, 90% Ti6Al4V + 10% AlMgScZr, 80% Ti6Al4V + 20% AlMgScZr, 60% Ti6Al4V + 40% AlMgScZr, 40% Ti6Al4V + 60% AlMgScZr, 20% Ti6Al4V + 80% AlMgScZr, 90% Ti6Al4V + 10% AlMgScZr, and 100% AlMgScZr, respectively;

[0064] S2: The printing powder with mass fraction of 100% Ti6Al4V is added into the powder supply port 7, the first high-pressure cylinder 10 connected to the powder feeding gas circuit 8 is opened, the gas pressure is adjusted through the first gas circuit valve 13, and the printing powder flows to the rotating powder changing arm 2;

[0065] S3: The rotating powder changing arm 2 is rotated to move in the projection direction to align with the first sub-compartment 19, the telescopic joint is extended downward to make the sealing cover 9 sealingly connected with the protruding part 20 (as shown in a of Figure 5 , the printing powder is stored in the first sub-compartment 19, the heating plate and the rotating stirring rod in the first sub-compartment 19 are turned on, and the first gas circuit valve 13 is closed to stop the gas supply of the powder feeding gas circuit 8;

[0066] S4: The first sub-compartment 19 connecting port is closed, the telescopic joint is retracted upward (as shown in b of Figure 5 , the printing powder with mass fraction of 90% Ti6Al4V+10% AlMgScZr is added into the powder supply port 7, the first high-pressure cylinder 10 connected to the powder feeding gas circuit 8 is opened, the gas pressure is adjusted through the first gas circuit valve 13, and the printing powder flows to the rotating powder changing arm 2 (as shown in c of Figure 5 );

[0067] S5: The rotating powder changing arm 2 is rotated clockwise to sequentially reach above the second to eighth sub-compartments 19, and the steps S2-S4 are repeated for the printing powders with different mass fractions until the eight kinds of component powders are stored in the respective sub-compartments 19;

[0068] S6: The first sub-compartment 19 corresponding door 21 is opened, the second high-pressure cylinder 12 connected to the powder falling gas circuit 3 is opened, the gas pressure is adjusted through the second gas circuit valve 14, the flow is controlled through the pressure limiting valve 16, the printing powder with mass fraction of 100% Ti6Al4V is made to enter the powder mixing assembly, is fully dispersed and uniformly falls to the forming base plate 6, so as to form a layer of printing powder with mass fraction of 100% Ti6Al4V on the forming base plate 6;

[0069] S7: The printing is performed on the layer of printing powder;

[0070] S8: The steps S6-S7 are repeated to perform layer-by-layer printing on the printing powder with mass fraction of 100% Ti6Al4V;

[0071] S9: The second to eighth sub-compartments 19 corresponding doors 21 are sequentially opened, and the steps S6-S8 are repeatedly performed until the printing of the eight kinds of printing powders with different mass fractions is completed, and a Ti6Al4V-AlMgScZr component gradient part is obtained.

[0072] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A powder spreading system for multi-material additive manufacturing, characterized in that: From top to bottom, it includes a powder feeding device, a powder storage chamber (1) and a powder spreading device; the powder feeding device includes a powder feeding air path (8) and a powder supply port (7) and a rotary powder exchange arm (2) arranged on the powder feeding air path (8) in sequence, the powder supply port (7) is used to add printing powder, the first end of the rotary powder exchange arm (2) can be rotatably connected to the powder feeding air path (8) and communicated with the powder feeding air path (8), and the second end of the rotary powder exchange arm (2) is provided with a powder feeding port; the interior of the powder storage chamber (1) The space is divided into a plurality of mutually independent compartments (19) along the circumferential direction, and the upper end of each compartment (19) is provided with a powder inlet (17) matching the powder feeding port, and the powder feeding port is connected with different powder inlets (17) by rotation to feed powder to different compartments (19) for storage, and the lower end of each compartment (19) is provided with a door (21), and the opening and closing control of the door (21) causes the printing powder in the corresponding compartment (19) to fall to the powder spreading device for powder spreading printing; The powder storage cabin (1) is a hollow inverted cone structure, and the powder spreading system further includes a powder dropping air path (3), the powder dropping air path (3) passes through the central axis of the powder storage cabin (1), and a partition is fixedly connected between the tube wall of the powder dropping air path (3) and the outer wall of the powder storage cabin (1), and the partition divides the internal space of the powder storage cabin (1) into a plurality of independent compartments (19), and the opening and closing control of each of the cabin doors (21) corresponds to the connection and separation of the compartment (19) and the powder dropping air path (3); There is a distance between the bottom end of the tube wall of the powder dropping gas path (3) and the bottom end of the powder storage cabin (1), so that there is an opening between the powder dropping gas path (3) and the lower end of each of the compartments (19), or the tube wall of the powder dropping gas path (3) is provided with an opening at a corresponding position at the lower end of each of the compartments (19); The hatch (21) is arranged between two adjacent partitions at the opening and can slide up and down along the outer wall of the powder dropping air path (3). The hatch (21) has a first position located above and a second position located below relative to the powder storage cabin (1). In the first position, the hatch (21) is located above the opening, and the opening enables the sub-cabin (19) to communicate with the powder dropping air path (3). In the second position, the hatch (21) is located at the opening, so that the sub-cabin (19) is separated from the powder dropping air path (3). The rotary powder exchange arm (2) further comprises a main section (201) and a telescopic section, wherein both the main section (201) and the telescopic section are tubular structures, the inner diameter of the main section (201) is larger than the outer diameter of the telescopic section, the main section (201) faces the powder inlet (17) and is fixedly connected to the second end of the rotary powder exchange arm (2), the telescopic section and the main section (201) are coaxially arranged, the telescopic section can be slid up and down and connected to the main section (201), the lower end of the telescopic section forms the powder feeding port, and the upward and downward sliding of the telescopic section drives the powder feeding port to rise and fall; A raised portion (20) is provided on the upper end surface of each compartment (19), the powder inlet (17) is provided on the raised portion (20), a sealing cover (9) is provided on the periphery of the powder delivery port, the sealing cover (9) matches the shape of the raised portion (20), and when the powder delivery port is in a position connected to any of the powder inlet (17), the sealing cover (9) is sealed and connected to the corresponding raised portion (20).

2. The powder spreading system for multi-material additive manufacturing according to claim 1, characterized in that: The powder spreading system further comprises a powder wholeing component, the powder wholeing component comprising a connecting section (11) and a powder wholeing section (4), the upper end of the connecting section (11) being connected to the powder storage chamber (1) and the connecting section (11) being in communication with the powder falling air path (3), the lower end of the connecting section (11) being connected to the powder wholeing section (4), the powder wholeing section (4) being a flat hollow structure with a plurality of small holes evenly distributed on the bottom surface; the connecting section (11) being provided with a powder flow meter and a pressure limiting valve (16) with an adjustable opening.

3. The powder spreading system for multi-material additive manufacturing according to claim 2, characterized in that: The powder spreading device comprises a scraper (5) and a forming substrate (6), wherein the forming substrate (6) is located directly below the whole powder assembly, and the scraper (5) is located above the forming substrate (6) and can slide in the horizontal direction, and the scraper (5) is used to spread the printing powder that falls from the small hole onto the forming substrate (6).

4. The powder spreading system for multi-material additive manufacturing according to any one of claims 1 to 3, characterized in that: Each of the compartments (19) is provided with a spiral stirring rod (18) inside, the spiral stirring rod (18) comprising a rotating shaft (181) and a spiral piece (182) obliquely surrounding the outside of the rotating shaft (181), the rotating shaft (181) and the spiral piece (182) being fixedly connected, the spiral stirring rod (18) being connected to an external motor, and the external motor controlling the spiral stirring rod (18) to rotate around the rotating shaft (181); And / or, the inner wall of each compartment (19) is provided with a heating plate.

5. A powder spreading method for multi-material additive manufacturing, characterized in that: The powder laying system for multi-material additive manufacturing according to any one of claims 1 to 4 comprises the following specific steps: Step 1: Prepare multiple materials required for additive manufacturing and form multiple different printing powders; Step 2: Add the first printing powder to the powder supply port (7); Step 3: Control the rotation angle of the rotary powder exchange arm (2) to above one of the powder inlets (17), introduce inert gas into the powder feeding air path (8), and adjust the air pressure so that the first type of printing powder flows into the corresponding compartment (19) through the powder feeding air path (8), the rotary powder exchange arm (2), the powder feeding port, and the powder inlet (17); Step 4: When the storage amount of the first printing powder reaches a preset requirement, the inert gas is stopped; Step 5: Repeat the operations of steps 2 to 4 in sequence until each type of printing powder is stored in its respective compartment (19); Step 6: According to the printing powder required for each layer of the additive manufacturing process, the hatch (21) of the compartment (19) storing the corresponding printing powder is controlled to open, so that the printing powder falls to the powder spreading device; Step 7: After the printing powder required for each layer flows out from the hatch (21), the corresponding hatch (21) is closed.

6. The powder spreading method for multi-material additive manufacturing according to claim 5, characterized in that: The materials in a variety of different printing powders are of the same type, and the ratios of different materials change in a gradient. A variety of printing powders are printed in sequence to form gradient material additive manufacturing.

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