A multi-material powder selection and powder recycling device for a 3D printer

Abstract

The application relates to a 3D printer multi-material powder selective powder laying and powder recycling device, which comprises a 3D printing part, a secondary material selecting part and a secondary material conveying part. The 3D printing part is used for laying and scraping the base material powder or the auxiliary material powder to form a base material powder layer with a predetermined thickness through the translational movement of a scraper assembly relative to a forming assembly, and discharging the excess base material powder or auxiliary material powder. The secondary material selecting part is located above the scraper assembly and is used for making the auxiliary material powder in a target auxiliary material box fall through the switch assembly of the target auxiliary material box by a pushing mechanism. The secondary material conveying part is located between the scraper assembly and the secondary material selecting part and is used for guiding the falling auxiliary material powder into a blanking gap. The powder collecting part is used for collecting the excess base material powder or auxiliary material powder. The 3D printer multi-material powder selective powder laying and powder recycling device can realize the on-demand selective laying and classified recycling of various auxiliary material powders, avoids powder cross contamination and reduces the printing cost.

Description

Technical Field

[0001] This application relates to the field of 3D printing technology, and in particular to a multi-material powder selection, powder spreading, and powder recycling device for a 3D printer. Background Technology

[0002] Powder bed electron beam 3D printing is an additive manufacturing technology that uses a high-energy electron beam as a heat source and powder materials as raw materials. Its basic principle is to uniformly spread powder onto the surface of a forming cylinder in a vacuum environment using a scraper to form a powder layer of a certain thickness. Then, a specific area of ​​this powder layer is scanned and sintered with an electron beam, and this process is repeated layer by layer until the part is formed. This technology is suitable for forming high-performance metal materials such as titanium alloys, nickel-based superalloys, and refractory metals, and has broad application prospects in high-end manufacturing fields such as aerospace and biomedicine. Currently, powder bed electron beam 3D printing equipment is typically equipped with only a single powder cylinder and can only use one type of base powder for part printing.

[0003] In existing technologies, to achieve multi-material printing, some solutions attempt to lay different types of powder in different printing layers of the forming cylinder or in different areas of the same layer by setting up multiple powder cylinders or changing the powder supply source during printing. This can achieve the forming of multi-material parts to a certain extent. However, the above solutions have the following problems: First, setting up multiple powder cylinders leads to complex equipment structure and high modification costs. Moreover, different powders are prone to cross-mixing during the switching and laying process, making it difficult to ensure the purity of the powder composition in each printing layer and affecting the forming quality of the parts. Second, after laying, excess powder is uniformly collected into the same powder receiving box. Different types of residual powder cannot be distinguished and reused after mixing, resulting in waste of powder raw materials and increasing production costs. Third, when it is necessary to increase the types of auxiliary materials, it is often necessary to add an additional power drive device to control the powder dropping action of more powder cylinders, further increasing the equipment modification cost, resulting in poor scalability and difficulty in flexibly adapting to the requirements of different printing processes for the types and quantities of auxiliary materials.

[0004] Therefore, it is necessary to improve one or more of the problems existing in the above-mentioned related technical solutions.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this disclosure is to provide a 3D printer multi-material powder selection, powder spreading, and powder recycling device, thereby overcoming at least to some extent one or more problems caused by the limitations and defects of related technologies.

[0007] This application provides a 3D printer multi-material powder selection, powder spreading, and powder recovery device, including: The 3D printing unit includes a molding chamber, a molding component, and a scraper assembly. The molding component is located in the molding chamber, and the scraper assembly has a material discharge gap, is slidably disposed above the molding component, and contacts the top surface of the molding component. The 3D printing unit is used to lay and smooth the base material powder or auxiliary material powder to form a base material powder layer of predetermined thickness by the translational movement of the scraper assembly relative to the molding component, and to discharge excess base material powder or auxiliary material powder. The auxiliary material selection unit, located above the scraper assembly, includes multiple auxiliary material boxes, a first slide bar, a second slide bar, and a pushing mechanism. The multiple auxiliary material boxes are fixedly disposed within the molding chamber and have a switch assembly at their bottom. The switch assembly is slidably disposed within the molding chamber via the first and second slide bars. The pushing mechanism selectively engages with the switch assemblies of the multiple auxiliary material boxes. The auxiliary material selection unit is used to push the switch assembly of the target auxiliary material box via the pushing mechanism, causing the auxiliary material powder within the target auxiliary material box to fall. An auxiliary material conveying unit, located between the scraper assembly and the auxiliary material selection unit, is used to guide the falling auxiliary material powder into the material drop gap; The powder collection section is used to collect the excess masterbatch powder or auxiliary material powder.

[0008] In one possible implementation, the molding assembly includes: a first powder feeding trough, a powder cylinder, and a molding cylinder; The powder cylinder has a first support plate inside, which is used to lift the raw material powder inside and overflow it from the powder cylinder. The molding cylinder has a second support plate inside, which is used to descend to a preset height. When the scraper assembly scrapes the overflowing master material powder or the falling auxiliary material powder into the molding cylinder, a powder layer of preset thickness is formed. The first powder inlet is used to discharge excess base material powder or auxiliary material powder after a powder layer of a preset thickness has been formed.

[0009] In one possible implementation, the scraper assembly includes: a hopper and a sliding scraper; The sliding scraper has a material drop gap in the middle, scraper plates on both sides of the material drop gap on the bottom surface, and a sliding element at one end; The collecting hopper is fixedly installed on the top surface of the sliding scraper, surrounding the material drop gap.

[0010] In one possible implementation, the auxiliary material box includes a storage cavity, a control lever, and a powder dispensing box; A powder discharge box is slidably disposed at the lower part of the storage chamber, and a powder discharge groove is provided on the bottom surface. The powder discharge groove has a downwardly inclined guide end on the side near the powder discharge box. One end of the control rod passes through the lower part of the storage cavity and is fixedly connected to the powder box, while the other end has a mating part. The bottom surface of the powder dispenser has a rotating base plate.

[0011] In one possible implementation, the pushing mechanism includes a control panel, a first pushing member, and a second pushing member; The first pushing member includes a first concave member and a third sliding rod, and the second pushing member includes a second concave member and a fourth sliding rod. The pushing directions of the first pushing member and the second pushing member are perpendicular. The top of the control panel is slidably connected to the third slide rod and the fourth slide rod, respectively, and the bottom has a mating groove that mates with the mating parts of the multiple auxiliary material boxes.

[0012] In one possible implementation, the first pusher is driven by a first electric linear actuator, and the second pusher is driven by a second electric linear actuator.

[0013] In one possible implementation, the auxiliary material selection section further includes a fixing plate and a fixing bracket; The auxiliary material box is fixedly installed in the molding chamber by a fixing plate; The fixed bracket is fixedly installed in the middle of the molding chamber, and the first slide rod and the second slide rod are fixedly installed between the fixed bracket and the inner wall of the molding chamber near the auxiliary material box.

[0014] In one possible implementation, the auxiliary material conveying section includes a slide and a baffle mechanism; The chute is located below the powder discharge trough, with one end fixedly connected to the inner wall of the forming chamber and the other end located above the material discharge gap and inclined towards the material discharge gap; The baffle mechanism is rotatably disposed at one end of the slide rail near the scraper assembly, and includes a baffle, a rotating rod, and a rotating component; the baffle is rotatably disposed at one end of the slide rail near the scraper assembly, one end of the rotating rod is fixedly connected to the baffle, and the other end is fixedly connected to the outer ring of the rotating component, and the rotating component is rotatably connected to the forming chamber.

[0015] In one possible implementation, the powder collection unit includes a first powder inlet box, a first powder receiving box, and a swing mechanism; The first powder receiving box has multiple powder receiving cavities. The upper end of the first powder guiding box is hinged to the first powder guiding groove. A fixing ring is provided on the side near the swing mechanism. The swing mechanism includes a fixing hook and a third electric linear push rod. The fixing hook is fixedly connected to the output end of the third electric linear push rod and hooked to the fixing ring.

[0016] In one possible implementation, the powder collection unit further includes a second powder inlet box and a second powder receiving box, and the molding component further includes a second powder inlet groove; the second powder inlet box is fixedly disposed at the lower part of the second powder inlet groove, and the second powder receiving box is located below the second powder inlet box.

[0017] The technical solution provided in this application may include the following beneficial effects: This application presents a multi-material powder selection, spreading, and recycling device for 3D printers. Through the selection and coordination of multiple auxiliary material boxes in the auxiliary material selection section and the pushing mechanism, it enables the on-demand selection and dropping of different types of auxiliary material powders. Combined with the scraper assembly in the 3D printing section, it spreads and smooths the base material powder or auxiliary material powder to form a powder layer of predetermined thickness. This achieves selective powder spreading and composite printing of multiple powder materials in the same device, breaking through the limitations of single-material printing, enriching the material diversity of printed parts, and meeting the printing needs of aerospace and biomedical fields for complex material systems and high-performance parts. Furthermore, the auxiliary material conveying section receives the falling auxiliary material powder and guides it into the material drop gap in the middle of the scraper assembly, allowing the auxiliary material powder to fall into the bottom of the scraper assembly through the drop gap, effectively preventing auxiliary material powder from falling into the bottom of the scraper assembly. During the conveying and falling process, the powder does not mix or cross-contaminate with the base material powder, ensuring the independence and purity of the powder composition between different printing layers. The doctor blade assembly simultaneously discharges excess powder during the translational powder spreading process, enabling continuous powder spreading without additional cleaning steps and improving printing efficiency. At the same time, the powder collection unit collects excess base material powder or auxiliary material powder discharged by the doctor blade assembly, preventing the mixing of the same type of powder during recycling. This achieves classified recycling and reuse of base material powder and various auxiliary material powders, reducing powder material waste and lowering printing costs. Furthermore, the auxiliary material selection unit, through the sliding guide cooperation of the first and second slide rods, can accommodate any number of auxiliary material boxes, providing excellent scalability and flexibly meeting the needs of different printing processes for the types and quantities of auxiliary materials.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0020] Figure 1 This diagram illustrates the structure of a multi-material powder selection, powder spreading, and powder recovery device for a 3D printer according to an exemplary embodiment of this disclosure. Figure 2This illustration shows another structural schematic diagram of the multi-material powder selection, powder spreading, and powder recovery device for a 3D printer in an exemplary embodiment of this disclosure; Figure 3 This diagram illustrates the structure of the auxiliary material selection section and the auxiliary material conveying section of the multi-material powder selection, powder spreading, and powder recovery device for a 3D printer according to an exemplary embodiment of this disclosure. Figure 4 This diagram illustrates the structure of the auxiliary material selection section of the multi-material powder selection, powder spreading, and powder recovery device for a 3D printer according to an exemplary embodiment of this disclosure. Figure 5 This diagram illustrates the structure of the auxiliary material selection unit pushing mechanism of the multi-material powder selection, powder spreading, and powder recovery device for a 3D printer according to an exemplary embodiment of this disclosure. Figure 6 This diagram illustrates the structure of the auxiliary material feeding section of the multi-material powder selection, powder spreading, and powder recycling device for a 3D printer in an exemplary embodiment of this disclosure. Figure 7 This diagram illustrates the structure of the powder leveling section of the multi-material powder selection, powder spreading, and powder recovery device for a 3D printer in an exemplary embodiment of this disclosure. Figure 8 This diagram illustrates the structure of the powder recovery section of a multi-material powder selection, powder spreading, and powder recovery device for a 3D printer, as shown in an exemplary embodiment of this disclosure.

[0021] Figure label: 100. 3D printing section; 110. Molding chamber; 120. Molding component; 121. First powder feeding trough; 122. Powder cylinder; 123. Molding cylinder; 124. Second powder feeding trough; 130. First through hole; 140. Heat insulation screen; 150. Scraper assembly; 151. Material collection hopper; 152. Sliding scraper; 1521. Material drop gap; 1522. Scraper; 1523. Sliding component; 200. Auxiliary material selection section; 210. Auxiliary material box; 211. First auxiliary material box; 2111. Material storage cavity; 2112. Control lever; 2113. Powder discharge box; 2114. Rotating base plate; 2115. Powder discharge trough; 2116. Guide end; 2117. Mating part; 212. Second auxiliary material box; 213. Third auxiliary material box; 220. First slide bar; 230. Second slide bar; 240. Pushing mechanism; 241. 1. Control panel; 2411. First mating groove; 2412. Second mating groove; 2413. Third mating groove; 242. First pusher; 2421. First concave part; 2422. Third slide rod; 243. Second pusher; 2431. Second concave part; 2432. Fourth slide rod; 244. First electric linear actuator; 245. Second electric linear actuator; 250. Fixing plate; 260. Fixing bracket; 300. Auxiliary material conveying unit; 310. Slide rail; 320. Baffle mechanism; 321. Baffle; 322. Rotating rod; 323. Limiting plate; 324. Rotating component; 325. Rotating motor; 330. Fixed rod. 400. Powder collection section; 410. First powder inlet box; 411. Fixing ring; 420. First powder receiving box; 421. First powder receiving cavity; 422. Second powder receiving cavity; 423. Third powder receiving cavity; 424. Fourth powder receiving cavity; 430. Second powder inlet box; 440. Second powder receiving box; 450. Swinging mechanism; 451. Fixing hook; 452. Third electric linear actuator. Detailed Implementation

[0022] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0023] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0024] This example embodiment first provides a 3D printer multi-material powder selection, powder spreading, and powder recovery device, referencing... Figures 1-2 As shown, the device includes: a 3D printing unit 100, an auxiliary material selection unit 200, an auxiliary material conveying unit 300, and a powder collection unit 400; The 3D printing unit 100 includes a forming chamber 110, a forming component 120, and a scraper assembly 150. The forming component 120 is located inside the forming chamber 110. The scraper assembly 150 has a material discharge gap 1521, is slidably disposed above the forming component 120, and contacts the top surface of the forming component 120. The 3D printing unit is used to lay and smooth the base material powder or auxiliary material powder to form a base material powder layer of predetermined thickness by the translational movement of the scraper assembly 150 relative to the forming component 120, and to discharge excess base material powder or auxiliary material powder. The auxiliary material selection unit 200, located above the scraper assembly 150, includes multiple auxiliary material boxes 210, a first slide bar 220, a second slide bar 230, and a pushing mechanism 240. The multiple auxiliary material boxes 210 are fixedly disposed within the molding chamber 110 and have a switch assembly at their bottom. The switch assembly is slidably disposed within the molding chamber 110 via the first slide bar 220 and the second slide bar 230. The pushing mechanism 240 selectively engages with the switch assemblies of the multiple auxiliary material boxes 210. The auxiliary material selection unit is used to push the switch assembly of the target auxiliary material box 210 via the pushing mechanism 240, causing the auxiliary material powder within the target auxiliary material box 210 to fall. The auxiliary material conveying unit 300 is located between the scraper assembly 150 and the auxiliary material selection unit 200, and is used to guide the falling auxiliary material powder into the material dropping gap 1521; The powder collection unit 400 is used to collect the excess master material powder or auxiliary material powder.

[0025] It should be noted that the "base powder" mentioned in this application refers to the basic powder material used to print the substrate of the formed part in a powder bed electron beam 3D printing equipment, that is, the single raw material powder used in the conventional printing process; the "auxiliary powder" refers to one or more functional powder materials that are added to a specific printing layer and are different from the base powder composition, used to achieve multi-material hybrid printing or gradient material printing. This application realizes the on-demand selection and dropping of various auxiliary powders through the auxiliary powder selection unit 200, and, together with the scraper assembly 150 of the 3D printing unit 100, sequentially lays the base powder and auxiliary powder on the upper surface of the forming cylinder 123, thereby realizing a composite printing process in which different printing layers use different powder raw materials. The various parts of the entire device cooperate and work together: the auxiliary material selection unit 200 selects the target auxiliary material according to the preset printing program and causes it to fall to the auxiliary material conveying unit 300. The auxiliary material conveying unit 300 temporarily stores the auxiliary material powder and guides it into the material drop gap 1521 in the middle of the scraper assembly 150 at an appropriate time. The scraper assembly 150 spreads the auxiliary material powder onto the surface of the forming cylinder 123 with its translational movement. Excess powder is then sorted and recycled by the powder collection unit 400. The coordinated operation of the above-mentioned parts jointly realizes the selective spreading and classified recycling function of multi-material powder.

[0026] In one embodiment, such as Figure 2 As shown, the molding component 120 includes: a first powder feeding trough 121, a powder cylinder 122, and a molding cylinder 123; The powder cylinder 122 has a first support plate inside, which is used to lift the powder of the parent material inside and overflow the powder cylinder 122; The forming cylinder 123 has a second support plate inside, which is used to descend to a preset height. When the scraper assembly 150 scrapes the overflowing master material powder or the falling auxiliary material powder into the forming cylinder 123, a powder layer of preset thickness is formed. The first powder inlet trough 121 is used to discharge excess base material powder or auxiliary material powder after a powder layer of a preset thickness is formed.

[0027] It should be noted that the first tray inside the powder cylinder 122 rises to a preset height before each powder spreading action, causing the base material powder to overflow from the top of the powder cylinder 122. The amount of overflow is determined by the rising height of the tray, thereby controlling the powder supply in a single spreading operation. The second tray inside the forming cylinder 123 descends by one layer thickness after each layer of printing is completed. This layer thickness is the predetermined thickness of the powder layer to be spread, typically between 50μm and 200μm, with the specific value set according to the printing process requirements. Figures 1-2 As shown, the scraper assembly 150 moves horizontally from left to right, scraping the master powder overflowing from the powder cylinder 122 or the auxiliary powder falling onto the scraper assembly 150 towards the forming cylinder 123 area. Under the pushing and leveling action of the scraper 1522, the powder fills the upper surface of the forming cylinder 123 and forms a uniform powder layer. The first powder inlet trough 121 is located on the right side of the forming cylinder 123. When the scraper assembly 150 pushes excess powder to the end of its stroke, the excess powder falls into the first powder inlet trough 121 under gravity and then enters the powder collection section 400. It is worth noting that the structural design of the forming assembly 120 in this application allows the master powder and auxiliary powder to share the same powder spreading path and leveling mechanism, eliminating the need for separate powder spreading channels for different powders, simplifying the equipment structure, and reducing manufacturing costs.

[0028] In one embodiment, such as Figure 7 As shown, the scraper assembly 150 includes: a hopper 151 and a sliding scraper 152; The sliding scraper 152 has a material drop gap 1521 in the middle, and scraper blades 1522 located on both sides of the material drop gap 1521 on the bottom surface, and a sliding member 1523 at one end. The collecting hopper 151 is fixedly installed on the top surface of the sliding scraper 152, surrounding the material drop gap 1521.

[0029] It should be noted that the material drop gap 1521 in the middle of the sliding scraper 152 extends along the length of the sliding scraper 152, and its width matches the spacing between the scrapers 1522, ensuring that the auxiliary material powder can smoothly pass through the gap and fall into the area between the two scrapers 1522. The collecting hopper 151 is fixedly installed on the top surface of the sliding scraper 152 and surrounds the material drop gap 1521. Its opening is in the shape of a funnel, which is wider at the top and narrower at the bottom. It is used to receive the auxiliary material powder from the auxiliary material conveying unit 300 and collect it into the material drop gap 1521, so as to prevent the auxiliary material powder from scattering to non-target areas and causing powder contamination during the falling process. The scraper 1522 can be a thin, comb-shaped metal scraper. Multiple scrapers 1522 are combined and installed on the bottom surface of the sliding scraper 152 and located on both sides of the material drop gap 1521. The bottom surface of the scraper 1522 is in contact with the top surface of the forming assembly 120 (i.e., the upper surfaces of the powder cylinder 122 and the forming cylinder 123). During the translation of the sliding scraper 152, a pushing force and shearing force are applied to the powder, so that the powder is evenly spread and scraped to a predetermined thickness. The sliding element 1523 can be a slider or a roller structure, which slides in cooperation with the guide rail in the forming chamber 110 to ensure that the translational movement of the scraper assembly 150 is smooth and directional. The combined design of the collecting hopper 151 and the material drop gap 1521 ensures that the auxiliary material powder can only fall between the scrapers 1522 when the scraper assembly 150 moves to below the auxiliary material conveying section 300, preventing premature leakage at non-target positions and ensuring the selectivity and accuracy of the powder spreading position.

[0030] Furthermore, the molding chamber 110 is also equipped with a translation drive mechanism for driving the scraper assembly 150 to reciprocate horizontally. The translation drive mechanism includes a drive motor, a reducer, a sprocket, a chain, and two parallel optical shafts. The output shaft of the drive motor is connected to the sprocket via the reducer. The chain is sleeved on the sprocket and its two ends are fixedly connected to the sliding member 1523 of the scraper assembly 150. The sliding member 1523 of the scraper assembly 150 is slidably connected to the two optical shafts via linear bearings. The two optical shafts are fixedly arranged in the molding chamber 110 along the translation direction of the scraper assembly 150, and the scraper assembly 150 reciprocates synchronously with the sliding member 1523.

[0031] It should be noted that the structure and control technology for driving the scraper assembly 150 to translate horizontally are common structures and control methods in existing equipment, and will not be elaborated upon in detail. For example, a motor-driven method can be used, specifically: the translation drive mechanism uses a motor to achieve the reciprocating translation of the scraper assembly 150. The drive motor is fixedly installed outside or inside the forming chamber 110. Its output shaft drives the sprocket to rotate after being reduced in speed and torque by a reducer. The sprocket drives the chain to move. Both ends of the chain are fixedly connected to the sliding member 1523, thereby converting the rotational motion of the sprocket into the linear reciprocating motion of the sliding member 1523. Two optical shafts are arranged parallel to each other in the forming chamber 110 along the translation direction of the scraper assembly 150. The sliding member 1523 slides with the two optical shafts through linear bearings and moves linearly along the optical shaft direction under the traction of the chain. The scraper assembly 150 is fixedly installed on the sliding member 1523 and moves synchronously with the sliding member 1523. When the drive motor rotates in the forward direction, the sliding member 1523 drives the scraper assembly 150 to translate towards the forming cylinder 123 to perform the powder spreading action; when the drive motor rotates in the reverse direction, the sliding member 1523 drives the scraper assembly 150 to translate in the reverse direction and return to the initial position. By controlling the reciprocating rotation of the drive motor, the reciprocating linear motion of the scraper assembly 150 can be realized, thereby completing the powder spreading and resetting actions. The above-mentioned transmission and guidance method of sprocket chain combined with optical axis slider is smooth transmission and high positioning accuracy. Moreover, the cooperation of the two optical axes and linear bearings can effectively withstand the powder resistance encountered by the scraper assembly 150 during the powder spreading process, ensuring that the scraper assembly 150 does not wobble or deviate during the translation process, meeting the requirements of repeatability positioning accuracy and motion stability of the translational motion of the scraper assembly 150 in powder bed electron beam 3D printing equipment. The translational speed of the scraper assembly 150 is coordinated with the rising speed of the first tray of the powder cylinder 122, the falling speed of the second tray of the forming cylinder 123, and the action sequence of the auxiliary material selection unit 200 and the auxiliary material conveying unit 300, and can be uniformly scheduled by the central control system.

[0032] In one embodiment, such as Figure 6 As shown, the auxiliary material box 210 includes a material storage chamber 2111, a control lever 2112, and a powder dispensing box 2113; The lower part of the storage cavity 2111 is slidably provided with a powder box 2113, and the bottom surface has a powder groove 2115. The powder groove 2115 has a downwardly inclined guide end 2116 on the side near the powder box 2113. One end of the control rod 2112 passes through the lower part of the storage cavity 2111 and is fixedly connected to the powder box 2113, and the other end has a mating part 2117; The bottom surface of the powder box 2113 has a rotating base plate 2114.

[0033] It should be noted that the storage chamber 2111 is used to store auxiliary material powder, and the powder discharge trough 2115 at its bottom is the outlet channel for the auxiliary material powder to flow out of the storage chamber 2111. The guide end 2116 is tilted downward so that when the powder discharge box 2113 is pushed to the side away from the control rod 2112, the rotating bottom plate 2114 on its bottom surface opens due to its own weight and presses against the guide end 2116, forming the discharge port of the powder discharge box 2113, so that the auxiliary material powder in the powder discharge box 2113 flows out sequentially through the discharge port of the powder discharge box 2113 and the powder discharge trough 2115. The powder box 2113 is slidably disposed at the lower part of the storage chamber 2111 and can reciprocate in the horizontal direction relative to the storage chamber 2111. When the powder box 2113 is in the closed position, the rotating bottom plate 2114 on its bottom surface closes the bottom of the powder box 2113 to prevent powder leakage. When the control lever 2112 pushes the powder box 2113 to the open position under the action of external force, the rotating bottom plate 2114 rotates downward and opens under the action of the powder's own weight and / or its own gravity, forming the discharge port of the powder box 2113. The auxiliary material powder falls sequentially through the discharge port of the powder box 2113 and the powder trough 2115 to the auxiliary material conveying section 300 below. The control lever 2112 passes through the lower side wall of the storage chamber 2111. One end is fixedly connected to the powder box 2113, and the other end has a mating part 2117 (such as a locking block, protrusion, or groove structure) for selectively engaging with the mating groove on the control plate 241 of the pushing mechanism 240. When the mating part 2117 of one auxiliary material box 210 engages with the mating groove of the control plate 241, the reciprocating motion of the pushing mechanism 240 drives the control lever 2112 and the powder box 2113 to move synchronously, realizing the opening and closing of the auxiliary material box 210. The powder boxes 2113 of multiple auxiliary material boxes 210 operate independently and do not interfere with each other, so there is no problem of different types of auxiliary materials mixing during the storage stage.

[0034] Furthermore, such as Figure 3 As shown, the auxiliary material conveying unit 300 includes a slide rail 310 and a baffle mechanism 320; The slide 310 is located below the powder discharge trough 2115, with one end fixedly connected to the inner wall of the forming chamber 110, and the other end located above the material discharge gap 1521 and inclined towards the material discharge gap 1521. The baffle mechanism 320 is rotatably disposed at one end of the slide 310 near the scraper assembly 150, and includes a baffle 321, a rotating rod 322, and a rotating component 324; the baffle 321 is rotatably disposed at one end of the slide 310 near the scraper assembly 150, one end of the rotating rod 322 is fixedly connected to the baffle 321, and the other end is fixedly connected to the outer ring of the rotating component 324, and the rotating component 324 is rotatably connected to the molding chamber 110.

[0035] It should be noted that the slide 310 is an inclined plate-shaped or trough-shaped structure. Its higher end is located directly below the powder dropper 2115 of the auxiliary material box 210, used to receive the auxiliary material powder falling from the powder dropper 2115; its lower end extends above the collection hopper 151 of the scraper assembly 150, and is directly opposite the material dropper gap 1521. The slide 310 is inclined towards the material dropper gap 1521, so that the auxiliary material powder can automatically slide down the surface of the slide 310 under its own weight, without the need for an additional power conveying device, simplifying the structure and preventing the powder from scattering during the conveying process. The baffle mechanism 320 is located at the lower end of the slide 310. Its baffle 321 flips down and fits tightly against the end of the slide 310 in the closed state, used to intercept the auxiliary material powder falling from the powder dropper 2115. Once a powder-feeding process is completed and all the target auxiliary material powder has fallen into the slide 310, the baffle 321 flips upward and opens under the drive of the rotating component 324. The intercepted auxiliary material powder then slides down the inclined surface of the slide 310 into the collection hopper 151. On the one hand, this ensures that the auxiliary material powder falling in the same batch can flow completely and continuously into the material-feeding gap 1521, avoiding inconsistent powder thickness due to uneven powder falling speed. On the other hand, it avoids interference between the auxiliary material powder and the movement of the scraper assembly 150 during the falling process. That is, the baffle 321 remains closed when the scraper assembly 150 is not in position, and only opens when the scraper assembly 150 moves to below the slide 310 and the material-feeding gap 1521 is aligned with the end of the slide 310. This ensures that the auxiliary material powder falls accurately between the scrapers 1522, avoiding powder spillage into non-target areas causing pollution and waste. Optionally, the number of slides 310 can be one or more. When there are multiple slides 310, each slide 310 corresponds to the powder dropping trough 2115 of each auxiliary material box 210, and the ends of each slide 310 converge above the collecting hopper 151 to realize that multiple auxiliary material powders share the same feed port. This can be adjusted according to the arrangement direction of the auxiliary material boxes 210, and this application does not limit it. A torsion spring or a return spring can be provided at the rotational connection between the baffle 321 and the slide 310 to keep the baffle 321 in a normally closed state in the non-driving state to prevent accidental powder leakage.

[0036] Understandably, the auxiliary material powder is spherical or near-spherical, with good flowability and extremely low adhesion to the surface of slide 310. It will not remain on the surface of slide 310 during the sliding process, which not only ensures the accuracy of the amount of auxiliary material dispensed at one time, but also avoids cross-contamination between different batches of auxiliary material powder. Clean switching can be achieved without setting up an additional cleaning mechanism.

[0037] Optionally, the slide 310 is connected to the fixed bracket 260 via a fixed rod 330.

[0038] Furthermore, such as Figure 3As shown, the baffle mechanism 320 also includes a limiting plate 323 and a rotating motor 325; the limiting plate 323 has an arc-shaped limiting hole, the rotating rod 322 passes through the arc-shaped limiting hole, and the rotating motor 325 is used to drive the rotating component 324 to rotate.

[0039] It should be noted that the rotating component 324 is a rotatable disc or bushing structure. Its outer ring is fixedly connected to one end of the rotating rod 322, and its inner ring or center is rotatably connected to the molding chamber 110, allowing the rotating component 324 to rotate relative to the molding chamber 110 around its axis. The output shaft of the rotating motor 325 is fixedly connected to the central shaft of the rotating component 324 or driven by a coupling, providing rotational driving force for the rotating component 324. The limiting plate 323 is fixedly installed on the inner wall of the molding chamber 110 or on the fixed bracket 260, and the arc of the arc-shaped limiting hole on it corresponds to the required rotation angle range of the baffle 321. Specifically, when the rotating motor 325 drives the rotating component 324 to rotate, the rotating rod 322 rotates accordingly. Since the rotating rod 322 passes through the arc-shaped limiting hole, the inner wall of the arc-shaped limiting hole physically limits the rotating rod 322. When the rotating rod 322 rotates to the extreme position at either end of the arc-shaped limiting hole, it is blocked and cannot continue to rotate, thereby precisely controlling the opening and closing angles of the baffle 321. Through the above limiting structure, the baffle 321 can achieve the same preset angle each time it opens, ensuring the consistency of the flow path and falling position when the auxiliary material powder is released, and avoiding powder scattering or blockage of the slide 310 due to angle deviation. The rotating motor 325 can be a stepper motor or a servo motor, and the control system precisely controls its rotation timing, rotation speed, and rotation angle according to the printing program to realize the automatic opening and closing control of the baffle 321. Optionally, the portion of the rotating rod 322 passing through the arc-shaped limiting hole can be fitted with a friction-reducing sleeve or a bearing to reduce friction with the limiting plate 323, thereby improving the smoothness of operation and service life. Simultaneously, the outer ring of the rotating component 324 can be fixed to the rotating rod 322 using a key connection or welding to ensure transmission rigidity and prevent drift in the opening angle of the baffle 321 due to loose connections. The timing of the baffle 321's opening and the movement position of the scraper assembly 150 need to be coordinated and controlled. Specifically, when the scraper assembly 150 moves below the slide 310 and the material drop gap 1521 is directly opposite the end of the slide 310, the control system drives the rotating motor 325 to open the baffle 321, ensuring that the auxiliary material powder falls directly into the material drop gap 1521 rather than scattering outside the scraper assembly 150. This coordinated control can be achieved by the central control system of the 3D printing equipment through limit switches or encoder feedback.

[0040] In one embodiment, such as Figures 4-5 As shown, the pushing mechanism 240 includes a control board 241, a first pushing member 242, and a second pushing member 243; The first pusher 242 includes a first concave member 2421 and a third slide bar 2422, and the second pusher 243 includes a second concave member 2431 and a fourth slide bar 2432. The pushing directions of the first pusher 242 and the second pusher 243 are perpendicular. The top of the control panel 241 is slidably connected to the third slide rod 2422 and the fourth slide rod 2432 respectively, and the bottom has a mating groove that mates with the mating parts 2117 of the multiple auxiliary material boxes 210.

[0041] Furthermore, such as Figure 4 As shown, the first pusher 242 is driven by the first electric linear actuator 244, and the second pusher 243 is driven by the second electric linear actuator 245.

[0042] It should be noted that the pushing mechanism 240 achieves the positional movement of the control plate 241 in the X and Y directions in the horizontal plane through the two-dimensional linkage of the first pushing member 242 and the second pushing member 243. The X direction is parallel to the first sliding rod 220, and the Y direction is perpendicular to the X direction. Specifically, the first pushing member 242 pushes the control plate 241 along the X direction, and the second pushing member 243 pushes the control plate 241 along the Y direction. The combined movement in these two directions allows the mating groove at the bottom of the control plate 241 to align with the mating part 2117 of any auxiliary material box 210. The first concave member 2421 and the second concave member 2431 are U-shaped or C-shaped structural members, respectively fixedly connected to the output ends of the first electric linear actuator 244 and the second electric linear actuator 245, transmitting the linear motion of the electric linear actuators to the control plate 241. The third slide bar 2422 and the fourth slide bar 2432 serve as guide elements for the first pusher 242 and the second pusher 243, respectively. The top of the control plate 241 is slidably connected to the third slide bar 2422 and the fourth slide bar 2432 to ensure that the control plate 241 remains horizontal and directionally accurate during movement. The first electric linear actuator 244 and the second electric linear actuator 245 are both programmable electric actuators, and their stroke and speed can be precisely adjusted by the control system to achieve accurate positioning of the control plate 241. Optionally, the number of mating slots at the bottom of the control plate 241 corresponds to the number of auxiliary material boxes 210. This application sets three mating slots for three auxiliary material boxes 210 as an example. However, when the number of auxiliary material boxes 210 is expanded to N (N≥1), the number of mating slots is also expanded to N. This can be achieved by simply adjusting the stroke range of the first pusher 242 and the second pusher 243 without adding an additional power source or complex modifications, thus exhibiting good scalability.

[0043] Specifically, such as Figure 5As shown, the control board 241 has a first mating groove 2411, a second mating groove 2412 and a third mating groove 2413. Its position can be changed by the pushing mechanism 240, and it can cooperate with the mating parts 2117 of the first auxiliary material box 211 / second auxiliary material box 212 / third auxiliary material box 213 respectively to realize the opening of the auxiliary material box 210.

[0044] In one embodiment, such as Figure 3 As shown, the auxiliary material selection section 200 also includes a fixing plate 250 and a fixing bracket 260; The auxiliary material box 210 is fixedly installed in the molding chamber 110 by a fixing plate 250; The fixed bracket 260 is fixedly disposed in the middle of the molding chamber 110, and the first slide rod 220 and the second slide rod 230 are fixedly disposed between the fixed bracket 260 and the inner wall of the molding chamber 110 near the auxiliary material box 210.

[0045] It should be noted that the fixing plate 250 is used to fix the main body of the auxiliary material box 210 to the side wall or top support of the molding chamber 110, ensuring that the material storage cavity 2111 remains stationary relative to the molding chamber 110, with only the powder box 2113 sliding relative to the material storage cavity 2111 under the action of the control rod 2112. The fixing bracket 260 is fixedly set in the middle of the molding chamber 110, serving as the supporting base for the first slide rod 220 and the second slide rod 230. The first slide rod 220 and the second slide rod 230 are parallel to each other and extend in the horizontal direction, together forming the X-direction guide rail of the control rod 2112. The control rod 2112 is provided with corresponding guide holes or guide grooves that slide in cooperation with the first slide rod 220 and the second slide rod 230. One end of the first slide bar 220 and the second slide bar 230 are fixedly connected to the fixed bracket 260, and the other end is fixedly connected to the inner wall of the molding chamber 110 near the auxiliary material box 210, forming a stable double support structure. This ensures that the slide bars do not bend or shift during the sliding of the control rod 2112, improving operational reliability. It is worth noting that the installation position of the fixed bracket 260 and the extension direction of the slide bars can be adjusted according to the actual spatial layout, as long as the mating groove of the control plate 241 can cover the mating parts 2117 on all control rods 2112. This application is not limited to this.

[0046] In one embodiment, such as Figure 1 and Figure 8 As shown, the powder collection unit 400 includes a first powder inlet box 410, a first powder receiving box 420, and a swing mechanism 450; The first powder receiving box 420 has multiple powder receiving cavities. The upper end of the first powder drawing box 410 is hinged to the first powder drawing groove 121. A fixing ring 411 is provided on the side near the swing mechanism 450. The swing mechanism 450 includes a fixing hook 451 and a third electric linear push rod 452. The fixing hook 451 is fixedly connected to the output end of the third electric linear push rod 452 and hooked to the fixing ring 411.

[0047] It should be noted that the upper end of the first powder-conducting box 410 is rotatably connected to the outlet of the first powder-conducting trough 121 via a hinge shaft, allowing the first powder-conducting box 410 to swing around the hinge shaft in a vertical plane. The lower outlet of the first powder-conducting box 410 is displaced horizontally as its swing angle changes, thereby aligning with different powder-receiving cavities in the first powder-receiving box 420. The first powder-receiving box 420 has multiple powder-receiving cavities, which are arranged sequentially along the swing trajectory of the lower outlet of the first powder-conducting box 410, and each powder-receiving cavity corresponds to collecting a different type of powder. The third electric linear push rod 452 of the swing mechanism 450 passes through the forming chamber 110, and its output end is fixedly connected to a fixing hook 451. The fixing hook 451 is hooked to a fixing ring 411 on the side wall of the first powder-conducting box 410. When the third electric linear push rod 452 extends or retracts, it pulls the fixing ring 411 through the fixing hook 451, causing the first powder-conducting box 410 to rotate around the hinge shaft to different angles. The extension and retraction stroke of the third electric linear actuator 452 corresponds one-to-one with the swing angle of the first toner cartridge 410. Different swing angles correspond to different toner receiving cavities in the first toner receiving cartridge 420. Therefore, by controlling the stroke of the third electric linear actuator 452, excess powder can be guided into the preset toner receiving cavity, achieving the classified recycling of base material powder and different types of auxiliary material powder. This classified recycling mechanism effectively avoids the mixing of different types of powder during the recycling process, improves the powder recycling rate, and reduces printing costs.

[0048] Specifically, there can be four powder receiving chambers, namely the first powder receiving chamber 421, the second powder receiving chamber 422, the third powder receiving chamber 423 and the fourth powder receiving chamber 424, which respectively collect the first auxiliary material powder, the second auxiliary material powder, the third auxiliary material powder and the master material powder.

[0049] In one embodiment, such as Figure 1 As shown, the powder collection unit 400 also includes a second powder inlet box 430 and a second powder receiving box 440. The molding component 120 also includes a second powder inlet groove 124. The second powder inlet box 430 is fixedly disposed at the lower part of the second powder inlet groove 124, and the second powder receiving box 440 is located below the second powder inlet box 430.

[0050] It should be noted that the second powder-drawing groove 124 and the first powder-drawing groove 121 are respectively located on both sides of the forming cylinder 123. They are structurally independent and are used to collect excess powder from the scraper assembly 150 in different stroke directions. Specifically, the first powder-drawing groove 121 is mainly used to collect excess powder pushed to the end of the stroke when the scraper assembly 150 moves from left to right, while the second powder-drawing groove 124 is used to collect excess powder pushed to the end of another stroke when the scraper assembly 150 moves from right to left (such as during return or reciprocating powder spreading). The second powder-drawing box 430 is fixedly installed at the lower outlet of the second powder-drawing groove 124, with its lower outlet directly aligned with the inlet of the second powder-receiving box 440. Since the second powder-drawing box 430 does not require oscillation switching, the powder it collects is usually base material powder. Therefore, the second powder-receiving box 440 can be configured as a single powder-receiving chamber structure for centralized collection of this type of powder. It is worth noting that in printing processes requiring bidirectional or reciprocating toner application, the second toner tray 430 and the second toner receiving tray 440 can simultaneously recover excess toner during the return stroke, preventing excess toner from accumulating or scattering within the forming chamber 110, thus improving the cleanliness and operational stability of the equipment. In printing processes requiring only unidirectional toner application, the second toner tray 124 and the second toner tray 430 can also serve as backup recovery channels or be used during maintenance and cleaning.

[0051] In one embodiment, such as Figure 1 As shown, the top surface of the molding chamber above the molding cylinder 123 has a first through hole 130 for allowing an electron beam to pass through the top surface of the molding chamber 110 and irradiate the powder layer inside the molding cylinder 123 to perform selective scanning sintering on the powder layer.

[0052] It should be noted that the first through-hole 130 is located on the top surface of the forming chamber 110 and directly above the forming cylinder 123, corresponding to the electron beam emission channel of the electron gun. After being generated by the electron gun, the electron beam is focused by the focusing coil and deflected by the deflection coil, then passes through the first through-hole 130 into the interior of the forming chamber 110, selectively melting and sintering the powder layer laid on the upper surface of the forming cylinder 123 according to a preset scanning path. The size and position of the first through-hole 130 must match the scanning range of the electron beam to ensure that the electron beam can still cover the entire forming area without obstruction even at the maximum deflection angle.

[0053] Furthermore, a heat shield 140 is provided above the forming cylinder 123 to surround the first through hole 130, which is used to reduce the heat radiation of the high temperature powder layer and molten metal in the forming cylinder 123 area to the top surface of the forming chamber 110 and the electron gun, while preventing the powder vapor from splashing and contaminating the first through hole 130 and the electron gun emission channel.

[0054] It should be noted that the heat shield 140 is a frame-type heat insulation structure surrounding the first through-hole 130, suspended above the top surface of the forming chamber 110 above the forming cylinder 123, and enclosing the first through-hole 130. During powder bed electron beam 3D printing, when the electron beam selectively scans and sinters the powder layer, the powder layer and molten metal reach extremely high temperatures, and a large amount of heat is transferred upwards through thermal radiation. Simultaneously, metal vapor deposits and splattered powder are generated during the sintering process. The heat shield 140 effectively blocks high-temperature radiation from being transmitted to the top surface of the forming chamber 110 and the electron gun, preventing the electron gun and related precision optical components from overheating and affecting the beam spot quality and lifespan. Furthermore, the heat shield 140 intercepts powder vapor deposits and splattered powder on its inner side, preventing them from contaminating the vacuum sealing surface of the first through-hole 130 and the electron gun exit channel, ensuring a clean electron beam transmission path. The heat shield 140 can adopt a multi-layer metal panel structure, with the inner panel forming a closed heat insulation structure and the outer panel further isolating thermal radiation. In addition, a certain gap is maintained between the bottom opening of the heat insulation screen 140 and the upper surface of the forming cylinder 123, which neither affects the translational powder spreading movement of the scraper assembly 150, but also effectively surrounds the heat radiation area below the first through hole 130.

[0055] Working principle: Base material powdering process: The first support plate inside the powder cylinder 122 rises to a preset height under the command of the control system, causing the base material powder to overflow from the top of the powder cylinder 122. Subsequently, the translation drive mechanism drives the scraper assembly 150 to move from one side of the powder cylinder 122 towards the forming cylinder 123. The scraper 1522 pushes and scrapes the overflowing base material powder towards the area of ​​the forming cylinder 123. Simultaneously, the second support plate inside the forming cylinder 123 descends by one layer thickness. Under the leveling action of the scraper 1522, the base material powder fills the upper surface of the forming cylinder 123, forming a uniform powder layer of a predetermined thickness. The scraper assembly 150 continues to move to the end of its stroke. After laying, excess base material powder falls into the first powder inlet trough 121 under gravity, and is then guided through the first powder inlet box 410 into the corresponding powder receiving cavity in the first powder receiving box 420 for recycling. The scraper assembly 150 then returns to its initial position, preparing for the next layer of powder laying.

[0056] Auxiliary material selection and dropping process: When additional auxiliary powder is needed at a specific layer during printing, the control system determines the target auxiliary powder type according to the preset printing program. The pushing mechanism 240 then activates: the first electric linear actuator 244 drives the first pushing member 242 to move along the X direction, and the second electric linear actuator 245 drives the second pushing member 243 to move along the Y direction. These two actuators work together to move the control plate 241 in the horizontal plane until the mating groove at the bottom of the control plate 241 aligns and engages with the mating member 2117 of the target auxiliary powder box 210. Subsequently, the first electric linear actuator 244 retracts, driving the control plate 241 to move the control rod 2112 and the powder dropper 2113 away from the control rod 2112. When the powder box 2113 is pushed to the side away from the control lever 2112, the rotating base plate 2114 rotates downward under its own gravity and closes to the guide end 2116 to open, forming the discharge port of the powder box 2113. The auxiliary material powder in the powder box 2113 flows out through the discharge port of the powder box 2113 and the powder trough 2115 in sequence, and falls onto the slide 310 of the auxiliary material conveying section 300 below.

[0057] Auxiliary material temporary storage and release process: When the auxiliary material powder falls to the bottom of the slide 310, it is intercepted and temporarily stored on the surface of the slide 310 because the baffle 321 is in the closed state. After the powder falling process of the target auxiliary material box 210 is completed, the control system drives the scraper assembly 150 to move horizontally towards the slide 310, and at the same time, the position of the scraper assembly 150 is detected in real time through the limit switch or encoder. When the scraper assembly 150 moves to the bottom of the slide 310 and the collection hopper 151 is facing the end of the slide 310, the rotary motor 325 drives the rotating component 324 to rotate, the rotating rod 322 rotates accordingly and drives the baffle 321 to flip upward and open. The auxiliary material powder temporarily stored on the slide 310 slides down the inclined slide 310 into the collection hopper 151 under its own weight. After being collected in the collection hopper 151, it falls into the area between the scrapers 1522 on both sides through the material falling gap 1521. Because the auxiliary material powder is spherical or near-spherical, it has good flowability and extremely low adhesion to the surface of the slide 310. The powder will not remain on the surface of the slide 310 during the sliding process, ensuring the accuracy of the amount of auxiliary material dispensed per batch and avoiding cross-contamination between different batches of auxiliary material powder. After the baffle 321 opens to release the auxiliary material powder, it rotates in the opposite direction to reset to the closed state under the drive of the rotating motor 325.

[0058] Auxiliary material powdering process: The scraper assembly 150, carrying auxiliary material powder, continues to move towards the forming cylinder 123. The auxiliary material powder falling between the scraper blades 1522 is spread onto the upper surface of the forming cylinder 123 by the pushing and leveling action of the scraper blades 1522, forming an auxiliary material powder layer, thereby realizing the addition of auxiliary material for this specific printing layer. The scraper assembly 150 continues to move to the end of its stroke. After spreading, the excess auxiliary material powder falls into the first powder inlet trough 121, and is guided through the first powder inlet box 410 into the corresponding powder receiving chamber in the first powder receiving box 420 for classification and recycling. The scraper assembly 150 then returns to its initial position to prepare for the next layer of powder spreading.

[0059] Powder sorting and recycling process: During the process of the scraper assembly 150 pushing excess powder into the first powder-guiding groove 121, the control system presets the stroke of the third electric linear pusher 452 according to the type of powder currently being laid. The third electric linear pusher 452 pulls the fixing ring 411 on the side wall of the first powder-guiding box 410 through the fixing hook 451, causing the first powder-guiding box 410 to rotate around the hinge axis to the corresponding angle, with its lower outlet aligned with the corresponding powder-receiving cavity in the first powder-receiving box 420. Excess base material powder or auxiliary material powder falls into the first powder-guiding box 410 through the first powder-guiding groove 121, and then enters the corresponding powder-receiving cavity through the lower outlet of the first powder-guiding box 410. Excess powder from each layer is guided into the preset powder-receiving cavity according to its powder type, thereby realizing the classified recycling of base material powder and different types of auxiliary material powder. When the scraper assembly 150 returns to its initial position, if there is residual powder on the scraper 1522, the residual powder is pushed to the second powder inlet trough 124 and falls into the second powder receiving box 440 for centralized collection via the second powder inlet box 430.

[0060] The above processes are executed cyclically in each layer of printing. The control system coordinates the rising of the first tray of the powder cylinder 122, the falling of the second tray of the forming cylinder 123, the movement of the translation drive mechanism, the powder selection and powder dropping of the auxiliary material selection unit 200, the opening and closing of the baffle mechanism 320, and the swing angle of the swing mechanism 450 according to the preset printing program. In this way, the selective laying, leveling and classification and recycling of the base material powder and various auxiliary material powders are completed layer by layer, and finally the composite printing of multi-material powders is realized.

[0061] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A multi-material powder selection, powder spreading, and powder recovery device for a 3D printer, characterized in that, include: The 3D printing unit includes a molding chamber, a molding component, and a scraper assembly. The molding component is located in the molding chamber, and the scraper assembly has a material discharge gap, is slidably disposed above the molding component, and contacts the top surface of the molding component. The 3D printing unit is used to lay and smooth the base material powder or auxiliary material powder to form a base material powder layer of predetermined thickness by the translational movement of the scraper assembly relative to the molding component, and to discharge excess base material powder or auxiliary material powder. The auxiliary material selection unit, located above the scraper assembly, includes multiple auxiliary material boxes, a first slide bar, a second slide bar, and a pushing mechanism. The multiple auxiliary material boxes are fixedly disposed within the molding chamber and have a switch assembly at their bottom. The switch assembly is slidably disposed within the molding chamber via the first and second slide bars. The pushing mechanism selectively engages with the switch assemblies of the multiple auxiliary material boxes. The auxiliary material selection unit is used to push the switch assembly of the target auxiliary material box via the pushing mechanism, causing the auxiliary material powder within the target auxiliary material box to fall. An auxiliary material conveying unit, located between the scraper assembly and the auxiliary material selection unit, is used to guide the falling auxiliary material powder into the material drop gap; The powder collection section is used to collect the excess masterbatch powder or auxiliary material powder.

2. The 3D printer multi-material powder selection, powder spreading, and powder recovery device according to claim 1, characterized in that, The molding component includes: a first powder feeding trough, a powder cylinder, and a molding cylinder; The powder cylinder has a first support plate inside, which is used to lift the raw material powder inside and overflow it from the powder cylinder. The molding cylinder has a second support plate inside, which is used to descend to a preset height. When the scraper assembly scrapes the overflowing master material powder or the falling auxiliary material powder into the molding cylinder, a powder layer of preset thickness is formed. The first powder inlet is used to discharge excess base material powder or auxiliary material powder after a powder layer of a preset thickness has been formed.

3. The 3D printer multi-material powder selection, powder spreading, and powder recovery device according to claim 1, characterized in that, The scraper assembly includes: a hopper and a sliding scraper; The sliding scraper has a material drop gap in the middle, scraper plates on both sides of the material drop gap on the bottom surface, and a sliding element at one end; The collecting hopper is fixedly installed on the top surface of the sliding scraper, surrounding the material drop gap.

4. The 3D printer multi-material powder selection, powder spreading, and powder recovery device according to claim 1, characterized in that, The auxiliary material box includes a material storage chamber, a control lever, and a powder dispensing box; A powder discharge box is slidably disposed at the lower part of the storage chamber, and a powder discharge groove is provided on the bottom surface. The powder discharge groove has a downwardly inclined guide end on the side near the powder discharge box. One end of the control rod passes through the lower part of the storage cavity and is fixedly connected to the powder box, while the other end has a mating part. The bottom surface of the powder dispenser has a rotating base plate.

5. The 3D printer multi-material powder selection, powder spreading, and powder recovery device according to claim 1, characterized in that, The pushing mechanism includes a control panel, a first pushing component, and a second pushing component; The first pushing member includes a first concave member and a third sliding rod, and the second pushing member includes a second concave member and a fourth sliding rod. The pushing directions of the first pushing member and the second pushing member are perpendicular. The top of the control panel is slidably connected to the third slide rod and the fourth slide rod, respectively, and the bottom has a mating groove that mates with the mating parts of the multiple auxiliary material boxes.

6. The 3D printer multi-material powder selection, powder spreading, and powder recovery device according to claim 5, characterized in that, The first pusher is driven by a first electric linear actuator, and the second pusher is driven by a second electric linear actuator.

7. The 3D printer multi-material powder selection, powder spreading, and powder recovery device according to claim 1, characterized in that, The auxiliary material selection section also includes a fixing plate and a fixing bracket; The auxiliary material box is fixedly installed in the molding chamber by a fixing plate; The fixed bracket is fixedly installed in the middle of the molding chamber, and the first slide rod and the second slide rod are fixedly installed between the fixed bracket and the inner wall of the molding chamber near the auxiliary material box.

8. The 3D printer multi-material powder selection, powder spreading, and powder recovery device according to claim 4, characterized in that, The auxiliary material conveying section includes a slide and a baffle mechanism; The chute is located below the powder discharge trough, with one end fixedly connected to the inner wall of the forming chamber and the other end located above the material discharge gap and inclined towards the material discharge gap; The baffle mechanism is rotatably disposed at one end of the slide rail near the scraper assembly, and includes a baffle, a rotating rod, and a rotating component; the baffle is rotatably disposed at one end of the slide rail near the scraper assembly, one end of the rotating rod is fixedly connected to the baffle, and the other end is fixedly connected to the outer ring of the rotating component, and the rotating component is rotatably connected to the forming chamber.

9. The 3D printer multi-material powder selection, powder spreading, and powder recovery device according to claim 2, characterized in that, The powder collection unit includes a first powder feeding box, a first powder receiving box, and a swinging mechanism; The first powder receiving box has multiple powder receiving cavities. The upper end of the first powder guiding box is hinged to the first powder guiding groove. A fixing ring is provided on the side near the swing mechanism. The swing mechanism includes a fixing hook and a third electric linear push rod. The fixing hook is fixedly connected to the output end of the third electric linear push rod and hooked to the fixing ring.

10. The 3D printer multi-material powder selection, powder spreading, and powder recovery device according to claim 9, characterized in that, The powder collection unit further includes a second powder inlet box and a second powder receiving box. The molding component further includes a second powder inlet groove. The second powder inlet box is fixedly disposed at the lower part of the second powder inlet groove, and the second powder receiving box is located below the second powder inlet box.

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