Additive manufacturing method and its blanking device, printing apparatus

Abstract

The application relates to an additive manufacturing method and a material dropping device and a printing equipment thereof. The equipment composition of the method comprises a material spreading device, a material dropping device and a polymerization device. The material dropping device forms an auxiliary composite layer on a forming surface; the polymerization device irradiates the auxiliary composite layer with low energy so that the auxiliary composite layer is roughly polymerized and fixed; the material dropping device spreads a main material on the auxiliary composite layer after rough polymerization and fixation to form a main composite layer; the polymerization device irradiates the auxiliary composite layer and the main composite layer with high energy so that the auxiliary composite layer and the main composite layer are fully polymerized into a solid layer. The above steps are repeatedly executed until a preset solid is formed. The additive obtained through the above steps has high plane resolution, can realize powder mixing ratio regulation of a "voxel" level design, and does not generate thickness accumulation error when continuously polymerizing and forming multiple layers.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, and in particular to additive manufacturing methods, blanking devices, and printing equipment. Background Technology

[0002] 3D printing technology, based on the principle of controlled polymerization of powder materials, is a major branch of additive manufacturing. Within the fundamental framework of multi-layer solid deposition modeling (points, lines, and surfaces), the fine particle size and free state of powder materials provide the necessary conditions for deploying the required materials to specific points, lines, and surfaces in three-dimensional space. Key supporting functions also include the energy or medium used to polymerize the deployed powder.

[0003] Based on the differences in their technical approaches, existing powder 3D printing equipment can be classified into categories such as: laser / electron beam powder bed polymerization, micro-jet powder bed polymerization, laser cladding, powder jet spraying, and powder slurry extrusion.

[0004] At the same time, the rapid development of powder 3D printing applications is also promoting the deepening and expansion of demand. In particular, in recent years, it has become increasingly difficult to meet the requirements of complex working conditions and extreme load conditions by relying solely on the structural design of homogeneous materials. There is an urgent need for powder 3D printing technology to provide a broader range of manufacturing capabilities for multi-material hybrid forming, and even the ability to precisely define material formulations by "voxels" in order to expand design freedom and meet increasingly complex application needs through both forming and control methods. Summary of the Invention

[0005] Therefore, it is necessary to address the problems of low planar resolution and poor layer thickness control accuracy in 3D printing technology by providing an additive manufacturing method with high planar resolution of powder material mixing ratio, wide dynamic adjustment range, high control accuracy, and precise polymer layer thickness control capability.

[0006] An additive manufacturing method includes the following steps:

[0007] A solid layer is formed on the forming surface;

[0008] Repeat the step of forming a solid layer on the forming surface until a preset solid is formed;

[0009] The step of forming a solid layer on the forming surface includes:

[0010] Auxiliary material is dropped onto the forming surface to form an auxiliary composite layer;

[0011] The auxiliary composite layer is irradiated with low energy to cause it to coarsely polymerize and solidify.

[0012] The main material is scraped and laid on the auxiliary composite layer after rough polymerization and fixation to form the main composite layer;

[0013] The auxiliary composite layer and the main composite layer are irradiated with high energy, causing them to fully polymerize into a solid layer.

[0014] In one embodiment, the step of dropping the auxiliary material onto the forming surface to form the auxiliary composite layer further includes: the forming surface descending a predetermined distance.

[0015] According to another aspect of this application, a printing apparatus is provided, comprising:

[0016] The forming chamber has a forming surface;

[0017] A material spreading device is located above the forming surface. The material spreading device includes a material spreading head, which can be controllably reciprocated along a first direction parallel to the forming surface.

[0018] And a material feeding device located above the forming surface, the material feeding device including at least one auxiliary material feeding head, the auxiliary material feeding head being located on one side of the material spreading device in the first direction, the auxiliary material feeding head being controllably reciprocating along the first direction.

[0019] In one embodiment, the auxiliary material discharge head includes a material discharge actuator, the material discharge actuator includes a feeding channel, one end of the feeding channel is provided with a feeding port, the other end of the feeding channel is provided with a material discharge port and a material collection port, and a reversing plate assembly is provided in the feeding channel, the reversing plate assembly can be rotated in a controlled manner so that the feeding port can be selectively connected to the material discharge port or the material collection port.

[0020] In one embodiment, the auxiliary material discharge head includes a storage bin, which is connected to the material collection port. The storage bin is equipped with a material retrieval mechanism for extracting materials to the material discharge execution mechanism.

[0021] In one embodiment, the feeding mechanism includes a screw extending from the bottom of the storage bin to the feed inlet, the screw being controllably rotatable about its own axis.

[0022] In one embodiment, the auxiliary material feeding head includes a material equalization mechanism and a feeding mechanism. One end of the material equalization mechanism is connected to the material taking mechanism, and the other end is connected to the feeding mechanism. It is used to homogenize the material and then output it to the feeding mechanism. The feeding mechanism is used to transport the material to the feed port.

[0023] In one embodiment, the material homogenizing mechanism includes a material homogenizing plate and a vibration unit. The material homogenizing plate extends longitudinally along a second direction relative to the first direction, and the vibration unit is connected to the material homogenizing plate. The vibration unit is used to drive the material homogenizing plate to vibrate in order to homogenize the material.

[0024] In one embodiment, the feeding mechanism includes a peristaltic plate and an electromagnetic excitation unit. The peristaltic plate is located between the material equalization plate and the feed inlet, and the electromagnetic excitation unit is connected to the peristaltic plate to drive the peristaltic plate to reciprocate between the material equalization plate and the feed inlet.

[0025] In one embodiment, the printing device includes a polymerization device disposed in the forming chamber, the polymerization device emitting directional energy toward a designated area of ​​the forming surface to achieve polymerization and fixation.

[0026] The above additive manufacturing method, based on the elemental composition of the main and auxiliary materials, obtains a planar powder distribution map of each auxiliary powder material. The feeding unit continuously feeds material row by row into the forming unit area according to the planar powder distribution map, generating an auxiliary composite layer. The auxiliary composite layer is then irradiated with low energy to coarsely polymerize and fix it, effectively avoiding disturbance to the auxiliary composite layer by the spreading unit and ensuring the accuracy of the planar distribution of the powder mixing ratio. Subsequently, the spreading unit places the main material on the auxiliary composite layer to form a main composite layer. The auxiliary composite layer and the main composite layer in the area to be polymerized are then irradiated with high energy to fully polymerize them into a solid layer. The additive manufacturing obtained through these steps has high planar resolution, enables "voxel" level design and powder mixing ratio control, and does not produce cumulative thickness errors when continuously polymerizing multiple layers. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a printing device provided in one embodiment of this application.

[0028] Figure 2 This is a cross-sectional schematic diagram of an auxiliary material feeding head provided in an embodiment of this application.

[0029] Figure 3 This is an isometric schematic diagram of an auxiliary material feeding head provided in an embodiment of this application.

[0030] Figure 4 This is a schematic diagram of control signal connections provided in an embodiment of this application.

[0031] Figure 5 This is a schematic diagram illustrating the first application of printing material to be laid on a molded substrate, according to an embodiment of this application.

[0032] Figure 6 This is a schematic diagram of the auxiliary composite layer generation process provided in an embodiment of this application.

[0033] Figure 7 This is a schematic diagram of low-energy polymerization provided in an embodiment of this application.

[0034] Figure 8 This is a schematic diagram of the main composite layer generation process provided in an embodiment of this application.

[0035] Figure 9 This is a schematic diagram of high-energy polymerization provided in an embodiment of this application.

[0036] Figure 10 This is a schematic diagram of an entity layer provided in an embodiment of this application.

[0037] Figure label:

[0038] 1. Printing equipment; 11. Forming chamber; 111. Support plate; 112. Forming cylinder; 1121. Forming substrate; 12. Material spreading device; 121. Material spreading head; 122. Second guide rail; 13. Material dropping device; 131. Auxiliary material dropping head; 1311. Material dropping actuator; 13111. Feeding channel; 13112. Feed inlet; 13113. Dropping outlet; 13114. Collection outlet; 13115. Soft magnetic valve plate; 13116. First electromagnetic wire 1. Coil group; 13117. Second electromagnetic coil group; 1312. Storage bin; 13121. Material handling mechanism; 1313. Material equalization mechanism; 1314. Feeding mechanism; 132. First guide rail; 14. Feeding device; 15. Purification device; 151. Air inlet; 152. Air outlet; 16. Polymerization device; 17. Material return device; 171. Material return port; 18. Controller; 2. Solid layer; 3. Free powder layer; 4. Auxiliary composite layer; 5. Main composite layer. Detailed Implementation

[0039] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0040] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0041] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0043] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0045] See Figure 1 , Figure 1 The diagram shows a schematic of a printing device 1 according to an embodiment of the present application. The printing device 1 provided in an embodiment of the present application can form a preset entity by printing layer by layer using printing material according to the digital model design to be printed.

[0046] Printing device 1 includes a forming chamber 11 and a controller 18 (see [link]). Figure 4 The system includes a material feeding device 14, a material dropping device 13, and a material spreading device 12. The forming chamber 11 serves to contain and support the material. The material feeding device 14 supplies material to the material spreading device 12, the material dropping device 13 drops material, and the material spreading device uses a scraper to spread material. The controller 18 is communicatively connected to the material spreading device 12, the material dropping device 13, and the material feeding device 14, and is used to issue corresponding commands to control the working status of these devices.

[0047] The forming chamber 11 has a cubic shell structure, and the length direction of the forming chamber 11 is defined as the first direction (i.e. Figure 1 The height direction of the forming chamber 11 is the second direction (i.e., the X direction). Figure 1 The width direction of the forming chamber 11 is the third direction (i.e., the Z-direction). Figure 1 (Y direction). The forming chamber 11 includes a support plate 111, a side plate and a top plate. The support plate 111 and the top plate are spaced apart in the second direction. The side plate is connected between the support plate 111 and the top plate to form a closed space. An openable forming chamber door is provided on the side plate. The aforementioned material laying device 12, material dropping device 13 and material feeding device 14 are all located in the forming chamber and work together to perform additive manufacturing tasks.

[0048] In some embodiments, the forming chamber 11 has a forming cylinder 112 on the side away from the top plate in the second direction (Y direction in the figure). The forming cylinder 112 has an opening at one end facing the support plate 111. The support plate 111 has a through hole corresponding to the opening end of the forming cylinder 112. The forming cylinder 112 has a forming substrate 1121 that can reciprocate in the second direction. The forming substrate 1121 can form a forming surface for laying printing material. In some embodiments, one end of the feeding device 14 is installed on the top plate of the forming chamber 11 and is located outside the aforementioned enclosed space, which facilitates the operator to quantitatively feed material from outside the forming chamber 11 to a designated area inside the forming chamber 11. The other end of the feeding device 14 extends through the top plate into the enclosed space and connects to the material laying device 12 to continuously supply material to the material laying device 12.

[0049] In some embodiments, the material feeding device 13 includes at least one auxiliary material feeding head 131 and a first guide rail 132, the first guide rail 132 extending along a first direction. The auxiliary material feeding head 131 is located on one side of the material spreading device 12 in the first direction, and the auxiliary material feeding head 131 can be controllably reciprocated along the first guide rail 132 in the first direction.

[0050] In a preferred embodiment, the auxiliary blanking head 131 extends along a third direction (Z direction in the figure), and when the auxiliary blanking head 131 reciprocates in the first direction, it can completely cover the area where the forming substrate 1121 is located.

[0051] In some embodiments, see Figure 2 , Figure 3 , Figure 2 A cross-sectional schematic diagram of an auxiliary material feeding head 131 according to an embodiment of this application is shown. The auxiliary material feeding head 131 includes a storage bin 1312, a material equalization mechanism 1313, a feeding mechanism 1314, and a material feeding execution mechanism 1311. The storage bin 1312 is used to store printing material. The material equalization mechanism 1313 is used to equalize the material provided by the storage bin 1312 along its long side, thereby outputting a strip of material. The feeding mechanism 1314 is used to propel the strip of material output by the material equalization mechanism 1313 to the material feeding execution mechanism 1311. The material feeding execution mechanism 1311 is used to control the printing material to fall onto the forming surface or be recycled back to the storage bin 1312.

[0052] Specifically, the storage silo 1312 is equipped with a material handling mechanism 13121 for extracting materials to the feed inlet 13112. Preferably, the material handling mechanism 13121 includes a screw extending from the bottom to the top of the storage silo 1312 and capable of controlled rotation around its own axis. A spirally extending material handling element is provided on the screw for extracting materials from the storage silo 1312 and carrying them out of the storage silo 1312 as the screw rotates around its own axis. By increasing or decreasing the screw speed, the strip powder output from the homogenizer can be thickened or thinned, and the rated powder output of the auxiliary discharge head 131 can be efficiently and conveniently increased or decreased.

[0053] The material feeding mechanism 1311 includes a feeding channel 13111. One end of the feeding channel 13111 has a feed inlet 13112 for connecting to the top of the storage bin 1312, and the other end has a discharge port 13113 and a collection port 13114. The discharge port 13113 faces the forming surface for discharging material, and the collection port 13114 is connected to the storage bin 1312 to recover excess printing material. A reversing plate assembly is provided in the feeding channel 13111. The reversing plate assembly can be rotated in a controlled manner so that the feed inlet 13112 can selectively connect to either the discharge port 13113 or the collection port 13114. Preferably, the discharge port 13113 is a strip-shaped discharge port 13113 extending along a third direction. The strip-shaped discharge port 13113 is composed of multiple micro-powder discharge ports arranged in a regular manner. The multiple micro-powder discharge ports can be arranged in a single row or in multiple staggered rows to increase the arrangement density and improve the powder discharge control resolution of the strip area.

[0054] Preferably, the commutation plate assembly includes a soft magnetic valve plate 13115 and multiple unit electromagnetic coils. The soft magnetic valve plate 13115 is located at the junction of the discharge port 13113 and the collection port 13114. When the soft magnetic valve plate 13115 is guided to the discharge port 13113, the feed port 13112 is connected to the collection port 13114, and vice versa. The soft magnetic valve plate 13115 provided in this embodiment does not contain any active components, has a simple structure, small weight, and is easy to manufacture into high-density, high-response-speed array devices. Furthermore, the control winding of the discharge actuator 1311 that generates the high-frequency alternating electromagnetic field provided in this embodiment is located outside the discharge actuator 1311, making assembly, wiring, maintenance, and replacement convenient.

[0055] Preferably, the multiple unit electromagnetic coils are divided into a first electromagnetic coil group 13116 and a second electromagnetic coil group 13117. The first electromagnetic coil group 13116 is located on opposite sides of the feed channel 13111, and the second electromagnetic coil group 13117 is arranged opposite to the first electromagnetic coil group 13116 in a second direction. In production operations, simply changing the phase sequence of the excitation current switch of any unit coil in the electromagnetic coil group can flip the guiding posture of the corresponding soft magnetic valve plate 13115, guiding it to the material drop port 13113 or the material collection port 13114. Furthermore, changing the duty cycle of the phase sequence current of each unit coil in the electromagnetic coil group can adjust the material drop distribution of the material drop port 13113, thereby more accurately controlling the accuracy of the material drop. In some embodiments, in addition to using soft magnetic materials, the valve plate can also use permanent magnet materials to provide greater flipping driving force and higher flipping response speed.

[0056] It should be noted that the material feeding actuator 1311 of the auxiliary feeding head 131 provided in this application, in addition to the valve-controlled bypass scheme in this embodiment, can also adopt an open-closed valve-controlled channel with high-speed response characteristics such as pneumatic or piezoelectric. In this case, auxiliary power, dispersion medium, etc. can be used to maintain the stability of powder flow performance.

[0057] In some embodiments, see Figure 2 , Figure 3 , Figure 3 The diagram shows an isometric view of an auxiliary material feeding head 131 according to one embodiment of this application. One end of the material equalization mechanism 1313 is connected to the material taking mechanism 13121, and the other end is connected to the feeding mechanism 1314. It is used to homogenize the material before outputting it to the feeding mechanism 1314. In some embodiments, the material equalization mechanism includes a material equalization plate and a vibration unit. The material equalization plate extends longitudinally along a second direction relative to the first direction, and the vibration unit is connected to the material equalization plate to drive the plate to vibrate and equalize the material. When the material taking mechanism 13121 feeds the material to the material equalization mechanism 1313, the vibration unit inside the material equalization mechanism 1313 causes the material to be distributed in a strip along a third direction, and the strip material is output to the feeding mechanism 1314 through the outlet of the material equalization mechanism 1313.

[0058] In some embodiments, the feeding mechanism 1314 includes a peristaltic plate and an electromagnetic excitation unit. The peristaltic plate is located between the equalization plate and the feed inlet, and the electromagnetic excitation unit is connected to the peristaltic plate to drive the peristaltic plate to reciprocate between the equalization plate and the feed inlet. Preferably, the electromagnetic excitation unit provides asymmetric reciprocating vibration excitation to the peristaltic plate, making the peristaltic plate move slowly and stably during feeding and quickly return to its initial position after feeding. Specifically, the slope of the excitation signal in the powder forward direction is gentle, while the slope of the excitation signal in the reverse direction is steep, so as to drive the material to peristalt forward through the material inertia and its asymmetric friction with the peristaltic plate. By adjusting the frequency, amplitude, and slope of the excitation signal in both directions, the magnitude and stability of the peristaltic forward speed of the strip powder can be changed.

[0059] In some embodiments, based on the material ratio of the digital model to be printed, multiple auxiliary feeding heads 131 can be provided. Each auxiliary feeding head 131 is equipped with an independent material bin and a feeding actuator 1311. When multiple auxiliary feeding heads 131 move continuously on the first guide rail 132 in parallel, each auxiliary feeding head 131 can adjust the material distribution of the feeding actuator 1311 in real time. Therefore, the more auxiliary feeding heads 131 there are, the higher the complexity of the deployable powder material distribution, thereby enabling the realization of more complex object geometries and achieving higher precision and resolution. Preferably, the feeding device 13 includes two auxiliary feeding heads 131, which are arranged at intervals in the first direction. It can be understood that when the feeding device 13 includes more auxiliary feeding heads 131, the auxiliary feeding heads 131 can also be arranged in a sequentially spaced manner in the first direction.

[0060] The material feeding device 13 provided in this application uses multiple auxiliary feeding heads 131 to deploy various auxiliary materials. It can not only realize the distribution control of the amount of each auxiliary material fed in the plane, but also the non-contact feeding method does not generate plane force disturbance, and the feeding positioning accuracy is high. It can avoid the material flow and diffusion caused by the plane force disturbance of contact feeding. Especially when the material is powder, it can effectively avoid the negative effects of powder flow and diffusion and its deterioration of the powder plane deployment accuracy.

[0061] In some embodiments, the material spreading device 12 is located above the forming surface, and the material spreading device 12 includes a second guide rail 122 and a material spreading head 121. The second guide rail 122 extends along a first direction and is spaced apart from the first guide rail 132 in a second direction. A driving device is provided inside the second guide rail 122, and the material spreading head 121 can be controllably reciprocated along the second guide rail 122 under the drive of the driving device.

[0062] In some embodiments, the spreading head 121 extends along the second direction. When the spreading head 121 reciprocates in the first direction, it can completely cover the area of ​​the forming substrate 1121. The spreading head 121 generates a material layer with a flat surface and constant height in the area of ​​the forming substrate 1121 by mechanical scraping.

[0063] In some embodiments, the printing device 1 further includes a purification device 15, which is connected to the forming chamber 11 and is used to provide preset atmosphere conditions for the forming chamber 11. In some embodiments, the purification device 15 includes an air inlet 151 and an air outlet 152, which are located on both sides of the forming chamber 11 in a first direction and form a complete purification loop through a control system outside the forming chamber 11. The purification device 15 draws in flue gas and splash particles from the forming chamber 11 through the air inlet 151, and returns them to the forming chamber 11 through the exhaust port after dust removal and purification.

[0064] In some embodiments, see Figure 8 The printing device 1 also includes a polymerization device 16, which is disposed in the forming chamber 11. The polymerization device 16 emits directional energy into a designated area on the forming substrate 1121 within the forming chamber 11 to achieve polymerization and fixation. In some embodiments, the directional electron energy can be a laser or an electron beam, etc., and this application does not limit this. The polymerization device 16 provided in this application has two irradiation modes: low energy and high energy. The low-energy irradiation mode is used to roughly fix the auxiliary composite layer 4 to form a coarse polymer, effectively avoiding disturbance of the auxiliary composite layer 4 by the material spreading device 12 and ensuring the accuracy of the planar distribution of the material mixing ratio; the high-energy irradiation mode is used for the complete polymerization of the main composite layer 5 and the coarse polymer to form a dense entity.

[0065] In some embodiments, the printing apparatus 1 further includes a material return device 17 for real-time recycling of excess material generated during the additive manufacturing process and inputting it into production to achieve resource recycling. In some embodiments, the material return port 171 is opened on the support plate 111 of the forming chamber 11, and the material return port 171 is a through hole extending along a second direction on the support plate 111. The body of the material return device 17 is located on the side of the support plate 111 away from the forming chamber 11. After the material spreading device 12 and the like pass through the area of ​​the forming substrate 1121, they can push residual material into the material return unit to keep the support plate 111 clean.

[0066] In 3D printing, a voxel is a pixel in three-dimensional space, similar to a pixel in a two-dimensional image, but with an additional dimension. Each voxel has three-dimensional coordinates and attributes such as color, density, and transparency. In 3D printing, a digitized 3D model is divided into individual voxels, and the printing equipment stacks these voxels layer by layer to create the three-dimensional shape of the object. Therefore, controlling the size and number of voxels can affect the quality and detail of the printed object, and voxel-based powder bed 3D printing also places higher demands on the printing equipment and methods. In some embodiments, the printing material of this application is a powder material to meet the aforementioned requirements of voxel-based powder bed 3D printing, providing a multi-material powder supply and spreading method and printing equipment 1 with high planar resolution and precise layer thickness control.

[0067] Some embodiments of this application also provide an additive manufacturing method, including the following steps:

[0068] S1: Form a solid layer on the forming surface.

[0069] Specifically, step S1 includes the following steps:

[0070] S11: Preset distance for the forming surface to descend.

[0071] Specifically, the controller 18 first sends a descent command to the forming cylinder 112, controlling the forming cylinder 112 to drive the forming substrate 1121 to descend the single-layer polymerization thickness.

[0072] It should be noted that when printing material is first laid on the molding substrate 1121, the molding surface is formed by the surface of the molding substrate 1121. However, once printing material is present on the molding substrate 1121, the previous layer of printing material forms the molding surface for the next layer of printing material. (See also...) Figure 5 , Figure 6 , Figure 5 The image shows the initial state when printing material is first laid on the molding substrate 1121. Figure 6 The image shows the state after printing material is present on the forming substrate 1121. At this time, the original forming surface includes the previous solid layer 2 and the free powder layer 3. The forming substrate moves the solid layer 2 and the free powder layer 3 to provide a new forming surface and printing space for the next layer of printing material.

[0073] S12: Drop auxiliary material onto the forming surface to form auxiliary composite layer 4.

[0074] Specifically, the controller 18 loads the slice data, reads the planar material distribution map of the "voxel" design, and solves the planar powder distribution map of each auxiliary powder material based on the composition of the main powder and each auxiliary powder material element.

[0075] The controller 18 sends a powder-feeding command to the feeding device 13, controlling the parallel auxiliary feeding heads 131 to pass through the area above the forming substrate 1121 at a uniform speed. During the movement of the auxiliary feeding heads 131, the feeding actuator 1311 adjusts its powder output distribution according to the planar powder distribution diagram of the matched powder material. When the feeding device 13 has finished moving, each auxiliary feeding head 131 generates an auxiliary composite layer 4 on the forming surface.

[0076] S13: Irradiate the auxiliary composite layer 4 with low energy to roughly polymerize and fix the auxiliary composite layer 4.

[0077] Specifically, see Figure 4 , Figure 7 The controller 18 sends a coarse polymerization command to the polymerization device 16, controlling the polymerization device 16 to irradiate the auxiliary composite layer 4 with low energy, so that the auxiliary composite layer 4 is coarsely polymerized and fixed.

[0078] S14: The main material is scraped and laid on the auxiliary composite layer 4 after rough polymerization and fixation to form the main composite layer 5.

[0079] Specifically, see Figure 4 , Figure 8 The controller 18 sends a powder supply command to the feeding device 14, controlling the feeding device 14 to deliver the main powder material required for single-layer powder spreading to the spreading device 12. The controller 18 sends a powder spreading command to the spreading device 12, controlling the linear module to drive the spreading head 121 to pass through the forming substrate 1121 area at a uniform speed. Under the scraping action of the spreading head 121, the main powder material fills and flattens the forming cylinder 112 area to the same height as the forming chamber 11 support plate 111, so as to form the main composite layer 5, and pushes the remaining powder into the return device 17.

[0080] S15: Irradiate the auxiliary composite layer 4 and the main composite layer 5 with high energy, so that the selected areas of the auxiliary composite layer 4 and the main composite layer 5 are fully aggregated into a solid layer.

[0081] Specifically, see Figure 1 , Figure 9 , Figure 10 The controller 18 sends a fine polymerization command to the polymerization device 16, controlling the polymerization device 16 to irradiate a selected area of ​​the auxiliary composite layer 4 and the main composite layer 5 with high energy. This fully polymerizes the coarse polymer and the main composite layer 5 covering it into a dense solid layer 2, which is tightly bonded to the forming surface. At this time, the forming surface includes the solid layer 2 and the free powder layer 3. Due to the shrinkage of powder polymerization and densification, the upper surface of the solid layer 2 is slightly lower than the upper surface of the free powder layer 3. Throughout the entire processing, the fumes and splashed particles generated by the polymerization device 16 irradiating the powder are circulated and purified by the purification device 15.

[0082] S2: Repeat step S1 of forming a solid layer on the forming surface until a preset solid is formed.

[0083] It can be understood that the subsequent solid layer is formed on the previous solid layer, and the subsequent solid layer and the previous solid layer are tightly bonded together to form a new solid layer after being irradiated by the high energy of the polymerization device 16. When the forming cylinder 112 drives the forming substrate 1121 to descend the single-layer polymerization thickness, the new solid layer and the free powder layer 3 descend as a whole, leaving a processing space between the forming substrate 1121 and the support plate 111, thereby starting the forming of the next solid layer.

[0084] Thus, multiple entity layers are accumulated one by one and stacked sequentially from bottom to top until all layer slice data has been processed, ultimately forming a complete preset entity. In some embodiments, before step S1, the printing device 1 needs to undergo initialization preprocessing, including the following steps:

[0085] First, based on the design data of the digital model to be printed, the main powder material for the spreading device 12 and one or more auxiliary powder materials for the dispensing device 13 are selected and determined. It should be noted that the determination of the main powder material and auxiliary powder material in this application is not related to the proportion of a single powder material. Any powder that exists globally in the "voxel" design, regardless of its proportion, can be designated as the main powder material. The special role of the main powder material is that its adapted spreading method can ensure the stability of the total powder deployment amount in a single layer. The powder deployment characteristics at any unit position in the forming substrate 1121 region of this application are quantitatively described as follows: Let the material composition of the "voxel" at a given unit position in the slice data be 10% a powder, 5% b powder, 1% c powder and 84% d powder, where a, b and c are designated as auxiliary powders. The amount of powder falling is affected by the accuracy of the feeding actuator 1311, and if there is a total deviation of n%, then when the feeding device 12 passes through the position, it automatically adjusts the main powder d to (84-n)% so that the total powder amount at the given unit position is always equal to 100%; the above-mentioned given unit position is valid in the forming substrate 1121 region.

[0086] Afterwards, sufficient main powder material is added to the feeding device 14, and one or more auxiliary powder materials are matched with each auxiliary discharge head 131. According to the matching relationship, the corresponding type and sufficient amount of auxiliary powder material are added to the powder hopper of the discharge device 13, and then the forming chamber door is closed.

[0087] Then, the elemental composition of the main powder material and each auxiliary powder material is input into the controller 18, the matching relationship between the auxiliary powder material and the auxiliary feeding head 131 is input into the controller 18, and the layered slicing data of the digital model to be printed is input into the controller 18.

[0088] The controller 18 sends a circulation purification command to the purification device 15, which controls the purification device 15 to replace the forming chamber 11 and the entire circulation loop with the set atmosphere conditions.

[0089] The controller 18 sends a zero-return command and a preheating command to the forming cylinder 112, controlling the forming cylinder 112 to drive the forming substrate 1121 to rise to the zero position, that is, to be flush with the support plate 111 of the forming chamber 11, and starts the preheating of the forming substrate 1121.

[0090] After the atmosphere replacement and preheating of the forming substrate 1121 reach the set target, the materials, data and process conditions for powder 3D printing are initialized and ready.

[0091] The additive manufacturing method provided in this application consists of a combination of powder dropping and powder spreading steps to generate the total amount of powder required for each voxel polymer layer. The former provides high-resolution powder mixing ratio control capability in a planar area, while the latter provides precise polymer layer thickness control. The combination of the two ensures the freedom of powder mixing ratio control and the continuous stability of powder spreading amount, achieving one of the important prerequisites for "voxel" design powder 3D printing.

[0092] In summary, this application utilizes multiple parallel auxiliary material spreading heads 121 of the feeding device 13, driven by a linear module, to achieve high-resolution planar control of the deployment of the auxiliary composite layer 4 through continuous row-by-row feeding. Furthermore, the feeding device 12 employs a covering and scraping method to achieve full coverage of the auxiliary composite layer 4 by the main material. This not only enables the control of the powder mixing ratio in voxel-based designs but also solves the problem of thickness accumulation error in continuous multi-layer powder polymerization at the macroscopic scale, without requiring additional high-performance powder sensors or complex measurement-compensation loops. The additive manufacturing method provided in this application is rationally designed, has high powder deployment resolution, and eliminates cumulative errors, making it easily applicable in various specifications of multi-powder material mixing or voxel-based powder bed 3D printing equipment 1.

[0093] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A printing device, characterized in that, include: A forming chamber having a forming substrate; A material spreading device is located above the forming substrate. The material spreading device includes a material spreading head, which can be controllably reciprocated along a first direction parallel to the forming substrate. as well as A blanking device is located above the forming substrate. The blanking device includes at least one auxiliary blanking head, which is located on one side of the spreading device in the first direction. The auxiliary blanking head can reciprocate in a controllable manner along the first direction. The auxiliary feeding head includes a feeding actuator, which includes a feeding channel. One end of the feeding channel has a feeding port, and the other end has a feeding port and a collecting port. A reversing plate assembly is provided in the feeding channel. The reversing plate assembly can be rotated in a controlled manner so that the feeding port can selectively connect to the feeding port or the collecting port. The feeding port is a strip-shaped feeding port extending along a third direction. The strip-shaped feeding port is composed of multiple micro powder feeding ports arranged in a regular pattern. The multiple micro powder feeding ports are arranged in a single row or multiple rows in a staggered arrangement. The reversing plate assembly includes a soft magnetic valve plate and multiple unit electromagnetic coils. The soft magnetic valve plate is located at the junction of the feeding port and the collecting port. The soft magnetic valve plate is a high-density, high-response-speed array device. It can change the phase sequence of the excitation current switching of any unit coil in the multiple unit electromagnetic coils to flip the guiding posture of the corresponding soft magnetic valve plate and guide the soft magnetic valve plate to the feeding port or the collecting port. The phase sequence current duty cycle of each unit coil in multiple unit electromagnetic coils can be changed to adjust the material discharge amount distribution at the discharge port.

2. The printing device according to claim 1, characterized in that, The auxiliary material discharge head includes a storage bin, which is connected to the material collection port. The storage bin is equipped with a material retrieval mechanism, which is used to extract materials to the material discharge execution mechanism.

3. The printing device according to claim 2, characterized in that, The material handling mechanism includes a screw that extends from the bottom of the storage bin to the feed inlet, and the screw can be controlled to rotate about its own axis.

4. The printing device according to claim 2, characterized in that, The auxiliary material feeding head includes a material equalization mechanism and a feeding mechanism. One end of the material equalization mechanism is connected to the material taking mechanism, and the other end is connected to the feeding mechanism. It is used to equalize the material and then output it to the feeding mechanism. The feeding mechanism is used to transport the material to the feed port.

5. The printing device according to claim 4, characterized in that, The material homogenizing mechanism includes a material homogenizing plate and a vibration unit. The material homogenizing plate extends longitudinally along a second direction relative to the first direction. The vibration unit is connected to the material homogenizing plate and is used to drive the material homogenizing plate to vibrate in order to homogenize the material.

6. The printing device according to claim 5, characterized in that, The feeding mechanism includes a peristaltic plate and an electromagnetic excitation unit. The peristaltic plate is located between the material equalization plate and the feed inlet. The electromagnetic excitation unit is connected to the peristaltic plate and is used to drive the peristaltic plate to reciprocate between the material equalization plate and the feed inlet.

7. The printing device according to claim 1, characterized in that, The printing equipment includes a polymerization device located in the forming chamber, which emits directional energy toward the forming substrate to achieve polymerization and fixation.

8. An additive manufacturing method, characterized in that, The additive manufacturing method, using the printing apparatus of any one of claims 1 to 7, comprises the following steps: A solid layer is formed on the forming surface; Repeat the step of forming a solid layer on the forming surface until a preset solid is formed; The step of forming a solid layer on the forming surface includes: Auxiliary material is dropped onto the forming surface to form an auxiliary composite layer; The auxiliary composite layer is irradiated with low energy to cause it to coarsely polymerize and solidify. The main material is scraped and laid on the auxiliary composite layer after rough polymerization and fixation to form the main composite layer; The auxiliary composite layer and the main composite layer are irradiated with high energy, causing them to fully polymerize into a solid layer.

9. The additive manufacturing method according to claim 8, characterized in that, Prior to the step of dropping auxiliary material onto the forming surface to form the auxiliary composite layer, the method further includes: The forming surface descends a preset distance.

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