Method of light-cured three-dimensional printing of microcellular structures and light-cured three-dimensional printing system

Abstract

The application provides a method for light-cured three-dimensional printing of a micro-porous structure and a light-cured three-dimensional printing system. The method comprises printing a plurality of target layers, each of the target layers comprising a plurality of micro-pores, and providing a gas flow to the plurality of micro-pores for removing un-solidified printing material in the plurality of micro-pores during the printing of the plurality of target layers, wherein the gas flow comprises a positive pressure gas flow or a negative pressure gas flow. The printing method and the printing system according to the application form a micro-porous structure without the need for ultrasonic cleaning after each layer is printed, avoiding the problems of complexity and poor printing effect caused by ultrasonic cleaning, and having the advantages of low cost, fast speed, high efficiency and high precision.

Description

Technical Field

[0001] This application mainly relates to the field of 3D printing, and in particular to a method and system for photopolymerization 3D printing of microporous structures. Background Technology

[0002] 3D printing technology uses a computer-aided 3D design model as a blueprint. Through software-based layer-by-layer discretization and numerical control molding, it utilizes laser beams, hot-melt nozzles, and other methods to deposit and bond special materials such as metal powder, ceramic powder, plastics, and cell tissues layer by layer, ultimately creating a physical product. Currently, the molding methods of 3D printing are constantly evolving, and the materials used are diverse. Among various molding methods, photopolymerization is a relatively mature method. Photopolymerization utilizes the principle that photocurable resin cures when exposed to ultraviolet light, allowing for material accumulation and molding. It features high molding precision, good surface finish, and high material utilization.

[0003] In the application of 3D printing technology, the printing of microporous structures is increasingly involved, such as medical microneedles in the field of biomedical materials. The diameter of a micropore can be as small as about 10 micrometers, while the length of the pore is about 1-2 mm or even longer. When printing micropores using high-viscosity resin or ceramic materials, the material in the micropores, although not solidified, remains inside the pores. The amount of material clogging the pores formed by a single printed layer may be small, but after multiple layers of printing, pores several millimeters long but only tens of micrometers in diameter are ultimately formed. If blockage occurs, it is completely impossible to clear the blockage in post-processing. Currently, to avoid micropore blockage, each solidified layer needs to be cleaned, for example, using ultrasonic tools to clean the remaining printed material in the pores in a cleaning solution to ensure unobstructed pinholes. However, this method undoubtedly increases the complexity of the process, has very low printing efficiency, and the cleaning solution can adversely affect the printing intensity and subsequent printing results. Summary of the Invention

[0004] The technical problem to be solved by this application is to provide a method and system for photopolymer 3D printing of microporous structures that can efficiently print microporous structures.

[0005] To address the aforementioned technical problems, this application provides a method for photopolymerization three-dimensional printing of microporous structures, comprising: printing several target layers, each of the target layers including several micropores; during the printing of the several target layers, providing airflow into the several micropores to remove uncured printing material from the several micropores; wherein the airflow includes positive pressure airflow or negative pressure airflow.

[0006] This application also provides a photopolymerization 3D printing system, comprising: a printing platform including a cavity and a support plate, the support plate having a plurality of through holes communicating with the cavity, the support plate being used to support a workpiece to be formed; an exposure device disposed opposite to the bottom of the cavity, for exposing printing material on the support plate; a lifting mechanism connected to the support plate, for driving the support plate to move up and down; an air supply device connected to the cavity for providing airflow into the cavity; and a controller configured to control the lifting mechanism, the exposure device, and the air supply device to print a workpiece including micropores according to the method described above, the micropores corresponding to at least one target through hole among the plurality of through holes.

[0007] The printing method and system of this application utilize an airflow supply device to provide a certain amount of airflow into the micropores, thereby removing uncured printing material adhering to the micropores and preventing micropore clogging. The micropore structure formed by the printing method and system of this application eliminates the need for ultrasonic cleaning after each layer, avoiding the complexity and poor printing results associated with ultrasonic cleaning. This method offers advantages such as low cost, high speed, high efficiency, and high precision. Attached Figure Description

[0008] The accompanying drawings are included to provide a further understanding of this application; they are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application. In the drawings:

[0009] Figure 1 This is a three-dimensional structural schematic diagram of a photopolymerization 3D printing system according to an embodiment of this application;

[0010] Figure 2 This is a cross-sectional view of a portion of the structure, including the printing platform, in a photopolymerization 3D printing system according to an embodiment of this application.

[0011] Figure 3 This is a top view of the printing platform in a photopolymerization 3D printing system according to an embodiment of this application;

[0012] Figure 4 This is an enlarged schematic diagram of a portion of the structure, including the target layer and the molded workpiece, formed by a photopolymerization three-dimensional printing method according to an embodiment of this application.

[0013] Figure 5 and Figure 6 This is an enlarged schematic diagram of a portion of the structure, including an auxiliary layer and a target layer, formed by a photopolymerization three-dimensional printing method according to an embodiment of this application.

[0014] Figure 7 This is a partial structural cross-sectional schematic diagram of the molded workpiece in a method according to an embodiment of this application;

[0015] Figure 8 This is an exemplary flowchart of a method for photopolymerization three-dimensional printing of microporous structures according to an embodiment of this application. Detailed Implementation

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0017] As indicated in this application, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0018] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0019] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms 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 on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0020] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0021] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0022] This application uses flowcharts to illustrate the operations performed by the system according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed precisely in sequence. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0023] The method and system for photopolymerization 3D printing of microporous structures in this application can be used to print microporous structures of any type and size, and are especially suitable for printing medical microneedles. The microneedles can be a single drug-releasing needle or a patch-type microneedle composed of multiple microneedles arranged in a matrix structure.

[0024] To facilitate the explanation of the photopolymerization 3D printing method for microporous structures in this application, the photopolymerization 3D printing system of this application will be described first.

[0025] Figure 1 This is a three-dimensional structural schematic diagram of a photopolymerization 3D printing system according to an embodiment of this application. (Reference) Figure 1As shown, the photopolymerization 3D printing system of this embodiment mainly includes a printing platform 110, an exposure device 120, a lifting mechanism 130, and an airflow supply device (not shown). Figure 1 The diagram shows an air pipe 140 connected to the housing of the printing platform 110 by an air supply device. Figure 1 The diagram also shows a material reservoir 101, a replenishment tank 102, and a scraper 103. The material reservoir 101 is used to hold liquid printing material. The printing material may be, for example, photosensitive resin or ceramic slurry, but may also be other materials; this application is not limited to these. At least a portion of the bottom plate of the material reservoir 101 is a light-transmitting plate, allowing a light beam emitted by the exposure device 120 to pass through the light-transmitting plate and illuminate the printing material located at the bottom of the material reservoir 101. The side of the printing platform 110 facing the material reservoir 101 (lower surface in the figure) is used to adhere the shaped workpiece. The exposure device 120 includes a light source 121, an image source assembly 122, and a projection lens 123. The exposure device 120 can be controlled by a controller (not shown) to illuminate the printing material at the bottom of the material reservoir 101 layer by layer according to the three-dimensional data model of the shaped workpiece to be generated. An example of the controller is a computer configured with the necessary control programs and capable of receiving and processing the three-dimensional data model.

[0026] This describes a basic printing process. First, the lifting mechanism 130 moves the printing platform 110 downwards, into the printing material in the storage tank 101, so that the gap between the lower surface of the printing platform 110 and the bottom of the storage tank 101 is the thickness of one printing layer. Second, the exposure device 120 emits a beam pattern towards the bottom of the storage tank 101 according to a predetermined program, so that the printing material at the bottom of the storage tank 101 is cured by the light according to the beam pattern. Third, the lifting mechanism 130 moves the printing platform 110 upwards, at which point a layer of the formed workpiece adheres to the lower surface of the printing platform 110. Optionally, when printing high-viscosity materials such as ceramic slurry, in order to ensure that the material between the printing platform 110 and the storage tank 101 can be squeezed to the thickness of one printing layer, before the lifting mechanism 130 moves the printing platform 110 downwards, a scraper 103 can be used to scrape out a material layer in the storage tank 101 that is slightly thicker than the thickness of one printing layer. After this series of actions, the next layer of the formed workpiece can be printed. Simultaneously, if the printing material in the storage tank 101 is insufficient, a certain amount of printing material can be replenished to the storage tank 101 by the replenishment tank 102. After multiple layers of printing, the printing process for the entire formed workpiece is completed. It should be noted that... Figure 1In the illustrated embodiment, the exposure device 120 is located below the material storage tank 101, and light shines upwards onto the printing material, which is referred to as a bottom-mounted 3D printing method. In other embodiments, the photopolymerization 3D printing system of this application can also be top-mounted, that is, the exposure device 120 is located above the material storage tank 101, and light shines downwards onto the printing material. Similarly, there can also be various other 3D printing methods such as left-mounted, right-mounted, front-mounted, and rear-mounted. This application uses a bottom-mounted method as an example for illustration and is not intended to limit the 3D printing system and method of this application to only bottom-mounted 3D printing methods. Based on the concept of this application, those skilled in the art can apply the 3D printing system and method of this application to any other 3D printing method.

[0027] refer to Figure 1 The air pipe 140 is positioned above the printing platform 110, that is, on the side of the printing platform 110 furthest from the workpiece. The air supply device is connected to the printing platform 110 via the air pipe 140, and the air supply device can be positioned anywhere.

[0028] Figure 2 This is a cross-sectional view of a portion of the structure, including the printing platform, in a photopolymerization 3D printing system according to an embodiment of this application. Figure 3 This is a top view of the printing platform in a photopolymerization 3D printing system according to an embodiment of this application. (Reference) Figure 2 and Figure 3 As shown, in this embodiment, the printing platform 110 includes a housing 210, a support plate 220, and a cavity 230. The cavity 230 is a sealed cavity formed by the housing 210 and the support plate 220. The support plate 220 has a first surface 221 and a second surface 222. The first surface 221 faces the bottom of the material storage tank 101 and is used to directly contact the printing material and the formed workpiece. The second surface 222 is the opposite surface of the first surface 221. A plurality of through holes 113 penetrate the support plate 220, and the cavity 230 communicates with the through holes 113. Figure 3 As shown, a plurality of through holes 113 are arranged in a matrix on the support plate 220. It should be noted that "a plurality of through holes 113" means that the number of through holes 113 is one or more. When printing the micro-hole structure, one through hole 113 may correspond to at least one micro-hole. For example... Figure 2 As shown, a plurality of molded workpieces 310 are shown on the first surface 221 of the support plate 220. Each molded workpiece 310 has a microhole 311. Some through holes 113a correspond to one molded workpiece 310, that is, one microhole, while some through holes 113b correspond to two molded workpieces 310, that is, two microholes 311. In some cases, a molded workpiece 310 includes multiple microholes, and the through hole 113 connects to at least one of the microholes.

[0029] like Figure 2As shown, the airflow supply device is connected to the printing platform 110 via an air pipe 140 to provide airflow to the support plate 220. Specifically, the airflow supply device can be a positive pressure device, used to provide positive pressure gas to the cavity 230, i.e., to blow air onto the support plate 220; the airflow supply device can also be a negative pressure device, used to provide negative pressure gas to the cavity 230, i.e., to draw air from above the support plate 220. Specifically, the housing 210 has an air pipe interface 211, and the air pipe 140 is connected to the air pipe interface 211 via a pipe connector 212. The pipe connector 212 is located at the connection between the air pipe 140 and the air pipe interface 211 to maintain the airtightness of the air pipe 140. The pipe connector 212 may also have a sealing structure that partially inserts into the air pipe interface 211.

[0030] It should be noted that, in Figure 2 The illustrated embodiment shows only one tracheal inlet 211 and one tracheal tube 140, with the tracheal inlet 211 located at a point on the housing 210. In other embodiments, multiple tracheal inlets 211 may be included, evenly distributed on the housing 210. These multiple tracheal inlets 211 can be connected to multiple tracheal tubes 140, which can be connected to a single main tracheal tube. This allows for a uniform airflow into the cavity 230, ensuring that the airflow rate and velocity are approximately the same throughout the cavity 230. This facilitates printing more finished workpieces while simultaneously removing printing material from multiple micropores. Since the volume of the cavity 230 is relatively large compared to the micropores in the finished workpiece 310, the position of the tracheal inlet 211 has a relatively small impact on the internal air pressure of the cavity 230. The cavity 230 also serves to balance pressure.

[0031] In some embodiments, the position of the air pipe interface 211 is selectable. For example, multiple air pipe interfaces 211 are provided on the housing 210, and each air pipe interface 211 can be sealed. Based on the distribution characteristics of the micropore structure of the molded workpiece to be printed, and in conjunction with the position of the micropore structure on the printing platform 110, one or more suitable air pipe interfaces 211 are selected to connect to the air pipe 140.

[0032] Figure 4 yes Figure 2 An enlarged schematic diagram of part of the structure, including the printing layer and the molded workpiece. Figure 8 This is an exemplary flowchart of a method for photopolymerization three-dimensional printing of microporous structures according to an embodiment of this application. The following is combined with... Figure 4 and Figure 8The method is described below. It should be noted that the method can be performed using the photopolymerization 3D printing system described above. This system also includes a controller configured to control the lifting mechanism 130, exposure device 120, and gas supply device to print a shaped workpiece including microholes, where the microholes correspond to at least one target through-hole among a plurality of through-holes on the support plate 220. Other 3D printing equipment can also be used to perform the method of this application.

[0033] refer to Figure 4 and Figure 8 As shown, the method of this embodiment includes the following steps:

[0034] Step S810: Print several target layers 410, each target layer 410 including several micropores. During the printing of several target layers 410, airflow is provided to the micropores to remove uncured printing material from the micropores. The airflow includes positive pressure airflow or negative pressure airflow. Figure 1 and Figure 2 For example, the air supply device in the curing 3D printing system of this application can be used to blow air into the micropores to provide positive pressure airflow, or to draw air in to provide negative pressure airflow.

[0035] Figure 4 The molded workpiece 310 shown is a needle-like structure, including a micropore 311. To form this molded workpiece 310, multiple target layers need to be printed, for example, 30-100 layers. Figure 4 This example shows 8 layers; the actual number of layers is not limited in this embodiment. Figure 4 In the diagram, the solid lines between layers represent the boundaries between them. During the printing process, after each target layer 410 is printed, the air supply device described above is used to blow or extract air to remove uncured printing material from the printed micropores 311, ensuring the holes are printed completely. These workpieces can be of any shape, but they contain one or more micropores 311 that are interconnected vertically and communicate with at least one target through-hole 114 on the support plate 220. The micropores and target through-holes are allowed to have a certain degree of vertical displacement and dimensional variation to ensure that oblique, curved, or shaped microchannel structures can be printed.

[0036] Combination Figure 4 The diagram shows eight target layers 410, in which micropores 311 are interconnected from top to bottom and linked together to form a conical pore, the diameter of which gradually decreases from top to bottom. It can be understood that, according to... Figure 1 The photopolymer 3D printing system shown uses eight target layers 410, arranged sequentially from top to bottom, for molding. Figure 4In the embodiment shown, the size of the micropores 311 in the target layer 410 printed first is larger than the size of the micropores 311 in the target layer 410 printed later. That is, the size of the micropores 311 in the target layer 410 located above is larger, and the size of the micropores 311 in the target layer 410 located further down is smaller. This process helps to perfectly print the micropores. Of course, completely consistent apertures are also allowed.

[0037] In some embodiments, after each target layer 410 is printed, air is blown or drawn into the micropores 311 in that target layer 410. According to such embodiments, residual printing material in the micropores 311 of each target layer 410 can be removed, keeping the micropores 311 open.

[0038] In other embodiments, after each multi-layer target layer 410 is printed, air is blown or drawn into the micropores 311 of the multi-layer target layer 410. These embodiments can be used for printing materials with low viscosity, allowing the blowing or drawing operation to be performed every few printing layers, while still keeping the micropores 311 of the multi-layer target layer 410 open.

[0039] like Figure 4 The formed workpiece 310 is a needle-like structure, and therefore its overall structure is also a cone-shaped structure, with a pinhole formed in the middle through a micro-hole 311.

[0040] In some embodiments, in step S810, during the printing of several target layers, the time for providing airflow to several micro-holes is between the following times: the start time t1 of the exposure process corresponding to the current target layer; and the liquid entry time t2 after printing the current target layer, the formed workpiece leaving the liquid surface of the printing material, and re-entering the liquid surface. Combined with... Figure 1As described above in the printing process, when printing the current target layer, the lifting mechanism 130 controls the printing platform 110 to move downwards. If the current target layer is the first layer, the lower surface of the printing platform 110 enters the printing material in the storage tank 101, and the distance between the printing platform 110 and the bottom of the storage tank 101 is one layer thickness. If the current target layer is not the first layer, the printing platform 110 moves to a position where the distance between the lower surface of the existing molded workpiece and the bottom of the storage tank 101 is one layer thickness. At this time, the controller controls the exposure device 120 to emit a beam pattern to the bottom of the storage tank 101 according to a predetermined program. The moment when the exposure device 120 emits the beam pattern is taken as the start time t1 of the exposure process. After the exposure and curing process of the current target layer is completed, the printing platform 110 lifts the molded workpiece, leaves the storage tank 101, and detaches it from the liquid surface. When printing the next layer, the printing platform 110 lifts the molded workpiece again and lowers it back into the storage tank 101. The molded workpiece re-enters the liquid surface at a liquid entry time t2. In these embodiments, blowing or evacuating is performed after the current layer of the molded workpiece has been printed to remove uncured printed material from the micropores. The discharged uncured printed material falls into the storage tank 101 or enters the cavity 230. According to these embodiments, airflow can be supplied to the micropores at any time between the start time t1 and the liquid entry time t2, and the airflow can be stopped at an appropriate time after the start of the airflow supply, which can be before the liquid entry time t2. The duration of the airflow supply is typically 1-10 seconds, sufficient to remove the liquid printed material from the micropores. The duration of the airflow supply can be determined experimentally. It is understood that the duration of the airflow supply is different for materials of different viscosities. For example, the duration of the airflow supply is shorter for low-viscosity materials and longer for high-viscosity materials. Typically, to reduce the impact of the airflow on the photocurable material, the airflow is supplied after leaving the surface of the photocurable material or the coating plane. In particular, for low-viscosity resins that are not slurries, negative pressure airflow should not be provided to them before the printed workpiece leaves the resin material, so as to prevent the resin material from being sucked into the micropores; preferably, if positive pressure airflow is provided, an uncured material collection device can be inserted between the molded workpiece 310 and the storage tank 101 before the airflow is provided, so as to prevent semi-cured material or other impurities that appear with the airflow from entering the storage tank 101 and thus contaminating the photocurable material.

[0041] In some embodiments, step S810, during the printing of several target layers, includes the step of providing airflow into several micropores:

[0042] Step S811: After printing one or more target layers, after the formed workpiece leaves the liquid surface of the printing material, provide airflow into several micropores; and

[0043] Step S812: Before the molded workpiece enters the printing material reservoir to print the next target layer, stop supplying airflow to several micro-holes.

[0044] According to steps S811 and S812, in this embodiment, airflow is not provided when the molded workpiece is below the liquid surface; airflow is only provided when the molded workpiece is not in a liquid environment. This embodiment also defines the duration of airflow provision, which varies depending on the material's viscosity and the size of the micropores. An example duration is 1-10 seconds.

[0045] In some embodiments, step S810, during the printing of several target layers, includes the step of providing airflow into several micropores:

[0046] Step S813: At the start of the exposure process corresponding to the current target layer, provide airflow into several micro-holes; and,

[0047] Step S814: When the exposure process corresponding to the current target layer ends and the material storage tank moves a predetermined distance away from the bottom, stop supplying airflow to the micro-holes.

[0048] According to step S813, the moment when airflow is supplied to the micropores corresponds to the start time t1 described above, at which time the molded workpiece is below the liquid surface. According to step S814, in some embodiments, the current target layer is still below the liquid surface when it moves a predetermined distance away from the bottom of the printing material reservoir 101. According to these embodiments, airflow is continuously supplied to the micropores during exposure, and the airflow is confined within the micropores because the target layer is attached to the bottom of the reservoir 101. Once the target layer moves away from the bottom of the reservoir 101, the airflow rushes out of the micropores and discharges the uncured printing material from the micropores. When the target layer moves a predetermined distance away from the bottom of the reservoir 101, the discharge of the uncured printing material is completed, and the airflow supply stops. In other embodiments, the current target layer is already above the liquid surface when it moves a predetermined distance away from the bottom of the reservoir 101. This embodiment starts blowing air earlier and is more suitable for cases with high-viscosity printing materials.

[0049] Figure 5 and Figure 6 This is an enlarged schematic diagram of a portion of the structure, including the auxiliary layer, according to an embodiment of this application. (In conjunction with...) Figure 5 and Figure 8 In some embodiments, prior to step S810, the following steps are also included:

[0050] Step S800: Print several auxiliary layers 510, wherein several target layers 410 are printed on the several auxiliary layers 510, that is, the target layers 410 are located below the auxiliary layers 510. Each auxiliary layer 510 includes several auxiliary holes 511. The size of the several auxiliary holes 511 is larger than the size of the several micro holes 311. Each auxiliary hole 511 is connected to at least one micro hole 311.

[0051] Furthermore, in conjunction with the photopolymerization 3D printing system of this application, in step S800, the support plate 220 for supporting the molded workpiece has a plurality of through holes 113, and a plurality of micro-holes 311 communicate with the target through hole 114a among the plurality of through holes 113. During the printing of a plurality of auxiliary layers 510, each auxiliary layer 510 is exposed to form the molded workpiece according to the corresponding first printing pattern. The first printing pattern is configured such that the auxiliary layer 510 closes the other through holes except for the target through hole 114a, so that airflow is provided to the micro-holes 311 only through the target through hole 114a and the auxiliary holes 511. Figure 5 As shown, the remaining through holes 114b are closed by one auxiliary layer 510, or they can be closed by multiple auxiliary layers 510.

[0052] In embodiments where the carrier plate 220 originally has multiple through holes 113, by configuring the first printed pattern, the auxiliary layer 510 covers all through holes on the carrier plate 220 except for the target through hole 114a, to ensure that airflow does not leak out through these through holes. Figure 5 The auxiliary layer 510 includes an auxiliary hole 511 at the position corresponding to the target through hole 114a, and covers other through holes (such as through hole 114b) to prevent air leakage. The size of the auxiliary hole 511 is larger than the size of the micropore 311 of the molded workpiece.

[0053] Since the size of the micropores 311 may be in the micrometer range, and the size of the auxiliary pores 511 may be in the millimeter range, pre-printing several layers of auxiliary layers 510 with larger auxiliary pores 511 facilitates the guidance of airflow into or out of the tiny micropores 311 to remove uncured printed material from the micropores 311. Figure 5 In this context, one target through hole 114a corresponds to one formed workpiece 310.

[0054] Combination Figure 6 and Figure 8Before printing the microneedles with micropores, in step S800, a cavity structure is printed using multiple auxiliary layers 510 to accommodate more microneedles or to print interfaces between the microneedles and other devices. Similarly, these auxiliary layers 510 must cover all through-holes on the carrier plate 220 except for the target through-hole 114a to ensure that airflow does not leak through these through-holes. In the initial stage of these auxiliary layers 510, some frames 512 are printed as needed. The layers of these frames 512 can have the same top and bottom dimensions or gradually change in size. Their size should meet the area requirements of the required number of microneedles, and must contain at least one target through-hole 114a. When the frames 512 reach a certain height, a top cover 513 is printed, and the microneedles are built on top of it. When the span of the top cover 513 is too large, other support structures or other methods can be used to ensure the stability of the printed structure, but this should not affect the airflow movement of the micropores 311.

[0055] like Figure 6 The top cover 513 leaves corresponding holes 514 at the locations where micro-holes 311 need to be printed. Usually, in the first few layers that make up the top cover 513 (hereinafter referred to as the top cover layer), because the printing layer is relatively thin, it is not possible to blow or evacuate air, so the auxiliary holes 514 will be relatively large to ensure that the complete auxiliary holes 514 can be printed even without blowing or evacuating air. Figure 6 An embodiment is shown where a target through-hole 114a corresponds to multiple molded workpieces 310. According to this embodiment, uncured printing material in the micropores 311 of three molded workpieces 310 can be removed simultaneously through a target through-hole 114a.

[0056] In some embodiments, the structure formed by the frame 512 and the top cover 513 can be an interface suitable for connecting multiple printed microneedles to other devices.

[0057] In some embodiments, during the printing of several target layers 410, each target layer 410 is exposed to form a molded workpiece according to a corresponding second printing pattern. The second printing pattern is configured such that multiple micro-holes corresponding to the positions in the several target layers 410 are interconnected to form a tapered channel. The size of the tapered channel on the extension surface of the several target layers 410 is reduced sequentially according to the printing order.

[0058] exist Figure 5 and Figure 6 In the illustrated embodiment, a plurality of auxiliary holes 511 in a plurality of auxiliary layers 510 are connected to form a conical hole, the diameter of which decreases sequentially from top to bottom. This design is beneficial for guiding airflow.

[0059] In some embodiments, during the printing of several target layers 410, each target layer 410 is exposed to form a molded workpiece according to a corresponding third printing pattern. The third printing pattern is configured such that the formed workpiece includes a microneedle, the microneedle including a body, a needle tip located at the tip of the body, a channel located inside the body, and a slope on the surface of the body, wherein the opening of the channel is located on the slope and has a preset distance between it and the needle tip.

[0060] Figure 7 This is a partial structural cross-sectional schematic diagram of the molded workpiece in a method according to an embodiment of this application. For example... Figure 7 As shown, the molded workpiece 700 is a microneedle, including a body 710 and a tip 720. The body 710 has a channel 730 inside, which can be a needle hole. The body 710 has a bevel 711. It should be noted that the molded workpiece 700 may also include other structures of the microneedle, such as a cylindrical needle body. Figure 7 The image shown only shows the needle tip. This needle tip is roughly conical; in other embodiments, the needle tip can also be cylindrical, with a portion cut off at an angle to form a bevel. For example... Figure 7 When the needle tip 720 is vertically downward, the channel 730 is inclined relative to the vertical direction, so that the opening of the needle hole 720 is located somewhere on the inclined surface 711, rather than at the needle tip 720. In application, the needle tip 720 is used to pierce the skin. If the opening of the channel 730 were at the needle tip 720, it might be blocked by skin or subcutaneous tissue, hindering injection. Therefore, placing the opening of the channel 730 on the inclined surface 711 allows the microneedle to provide injection more effectively. The channel 730 is very small. According to the printing method of this application, after curing one layer, the uncured printing material in the needle hole is removed by an airflow supply device, effectively preventing needle hole clogging.

[0061] In some embodiments, step S800, during the printing of several auxiliary layers 510, further includes: providing airflow into several auxiliary holes 511 to remove uncured printing material from the several auxiliary holes 511.

[0062] Typically, when forming the top cap layers, because the cap layers are relatively thin, air blowing or suction cannot be performed. Therefore, the auxiliary holes 514 in the cap layers are relatively large to ensure that complete holes can be printed even without air blowing or suction. Once the cap layers have sufficient strength (e.g., a thickness of 100-200 micrometers), after each layer is printed, air blowing or suction can be used via the airflow supply device described above to remove uncured printing material from the auxiliary holes 514, ensuring that the auxiliary holes 514 are printed completely. At this point, the diameter of the auxiliary holes 514 can gradually decrease according to the printing sequence, and they are connected from top to bottom until printing is complete. Figure 5The auxiliary layer 510 shown here has 8 layers; this is just an example, and the number can be more.

[0063] In some embodiments, during step S800, the time for providing airflow to the auxiliary holes 511 during the printing of several auxiliary layers 510 is between the following times: the start time t11 of the exposure process corresponding to the current auxiliary layer; and the liquid entry time t22 after the current auxiliary layer is printed, the molded workpiece leaves the liquid surface of the printing material, and re-enters the liquid surface. This step is similar to the corresponding printing process of the target layer 410 described above, and will not be elaborated further.

[0064] In some embodiments, in step S800, the step of providing airflow to the auxiliary holes 511 during the printing of several auxiliary layers 510 includes:

[0065] Step S801: After printing one or more auxiliary layers 510, after the molded workpiece leaves the liquid surface of the printing material, airflow is supplied to a plurality of auxiliary holes 511; and,

[0066] Step S802: Before the molded workpiece enters the printing material storage tank to print the next target layer, stop supplying airflow to several auxiliary holes 511.

[0067] In some embodiments, in step S800, the step of providing airflow to the plurality of auxiliary holes 511 during the printing of a plurality of auxiliary layers 510 includes:

[0068] Step S803: At the start of the exposure process corresponding to the current auxiliary layer, airflow is supplied to a plurality of auxiliary holes 511; and,

[0069] Step S804: When the exposure process corresponding to the current auxiliary layer ends and the material storage tank of the printing material is moved a predetermined distance away from the bottom, stop supplying airflow to the auxiliary holes.

[0070] According to the above embodiments, when providing airflow, airflow is provided to the auxiliary hole 511 and the micro hole 311, thereby removing uncured printing material from the auxiliary hole 511 or the micro hole 311.

[0071] In some embodiments, the printing material for the auxiliary layer is liquid photosensitive resin, which has strong fluidity and weak viscosity. After one auxiliary layer is printed, when the lifting mechanism 130 moves the printing platform 110 upward, some material flows out from the auxiliary hole 511, while some material remains in the auxiliary hole 511. The liquid photosensitive resin remaining in the auxiliary hole 511 is easy to clean later, so it does not need to be removed by blowing air.

[0072] In some embodiments, the printing material used for printing auxiliary layers can be a ceramic slurry. This material has low fluidity and high viscosity. After printing one auxiliary layer, when the lifting mechanism 130 moves the printing platform 110 upward, the material will also adhere to the auxiliary holes, and can therefore be removed by blowing or sucking air. Furthermore, this application does not limit the frequency and timing of blowing or sucking air into the auxiliary holes. In some embodiments, after each auxiliary layer is printed, air is blown into the auxiliary holes of that auxiliary layer to remove the material. In other embodiments, considering that blowing may damage the thinner molding layer when the number of layers is small, the printing material in the auxiliary holes is removed by blowing air only after multiple auxiliary layers, such as 3-5 layers, have been printed.

[0073] In some embodiments, the printing material for printing several target layers is a ceramic slurry, which is a photosensitive resin containing ceramic powder. Considering the practical application of microneedles, using ceramic materials to form the required microneedles is more suitable, as it has the characteristics of high strength, high precision, and good biocompatibility.

[0074] When the auxiliary layer and the target layer are printed using different printing materials, after step S800, the steps of cleaning the residual printing material in the storage tank and replacing the printing material are also included.

[0075] In some embodiments, after steps S800 and S810, the process may further include: sintering the molded workpiece, wherein during the sintering process, the resin in the slurry is vaporized, which is called degreasing, and after degreasing, high-temperature sintering is performed according to the ceramic material process requirements.

[0076] Furthermore, the controller can preprocess the three-dimensional data model of the molded workpiece, ensuring that each microhole corresponds to a target through-hole on the bearing surface. It also preprocesses the printing patterns of the auxiliary structures in the auxiliary layer and the molded workpiece in the target layer 410.

[0077] This application does not impose any restrictions on the size of the micropores. Typically, for microneedles, the pore diameter is around 2-100 micrometers.

[0078] Using the printing method and system of this application, during the printing of micropores, a certain amount of airflow is provided to the micropores in a timely manner through an airflow supply device, thereby removing the printing material adhering to the micropores and preventing micropore blockage. Furthermore, by printing multiple auxiliary layers, the multiple auxiliary holes together form a conical closed cavity, which is more conducive to airflow guidance and enhances the airflow intensity, accurately and quickly removing uncured printing material from the micropores.

[0079] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0080] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0081] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0082] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in this application are approximate values, which may be changed according to the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit preservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this application are approximate values, in specific embodiments, such numerical values ​​are set as precisely as feasible.

Claims

1. A method for photopolymerization three-dimensional printing of microporous structures, characterized in that, include: A number of target layers are printed, each of which includes a number of micropores. During the printing of the target layers, airflow is provided to the micropores to remove uncured printing material from the micropores. The airflow includes positive pressure airflow or negative pressure airflow. Before printing several target layers, several auxiliary layers are also printed, wherein the target layers are printed on the auxiliary layers, and each auxiliary layer includes several auxiliary holes, the size of which is larger than the size of which is a micropore, and each auxiliary hole is connected to at least one micropore.

2. The method as described in claim 1, characterized in that, During the printing of the target layers, the airflow is supplied to the micropores at times between the following moments: The start time of the exposure process corresponding to the current target layer; and The moment of liquid entry after the current target layer has been printed, the formed workpiece has left the liquid surface of the printing material, and then re-enters the liquid surface.

3. The method as described in claim 1, characterized in that, The step of providing airflow into the micropores during the printing of several target layers includes: After each or multiple target layers are printed, airflow is supplied to the plurality of micropores after the formed workpiece leaves the liquid surface of the printing material; and Before the molded workpiece enters the storage tank of the printing material to print the next target layer, the airflow to the plurality of micropores is stopped.

4. The method as described in claim 1, characterized in that, The step of providing airflow into the micropores during the printing of several target layers includes: At the start of the exposure process corresponding to the current target layer, airflow is supplied to the plurality of micropores; and, When the exposure process corresponding to the current target layer ends and the material moves a predetermined distance away from the bottom of the printing material storage tank, the airflow to the plurality of micropores is stopped.

5. The method as described in claim 1, characterized in that, The support plate for supporting the molded workpiece has a plurality of through holes, and the plurality of micro holes are connected to the target through hole among the plurality of through holes. During the printing of the plurality of auxiliary layers, each of the auxiliary layers is exposed to form the molded workpiece according to the corresponding first printing pattern. The first printing pattern is configured such that the auxiliary layer closes the other through holes except the target through hole, so that airflow is provided to the micro hole only through the target through hole and the auxiliary hole.

6. The method as described in claim 1, characterized in that, During the printing of several target layers, each target layer is exposed to form a shaped workpiece according to a corresponding second printing pattern. The second printing pattern is configured such that multiple micro-holes corresponding to the positions in the several target layers are interconnected to form a conical channel. The size of the conical channel on the extension surface of the several target layers decreases sequentially according to the printing order.

7. The method as described in claim 1, characterized in that, During the printing of several target layers, each target layer is exposed to form a molded workpiece according to a corresponding third printing pattern. The third printing pattern is configured such that the formed workpiece includes a microneedle, the microneedle including a body, a needle tip located at the tip of the body, a channel located inside the body, and an inclined surface on the surface of the body, wherein the opening of the channel is located on the inclined surface and has a preset distance between it and the needle tip.

8. The method as described in claim 1, characterized in that, The process of printing several auxiliary layers also includes: providing airflow into the several auxiliary holes to remove uncured printing material from the several auxiliary holes.

9. The method as described in claim 8, characterized in that, During the printing of the auxiliary layers, the airflow is supplied to the auxiliary holes at times between the following moments: The start time of the exposure process corresponding to the current auxiliary layer; and The moment of liquid entry after the current auxiliary layer has been printed, the formed workpiece has left the liquid surface of the printing material, and then re-enters the liquid surface.

10. The method as described in claim 8, characterized in that, The step of providing airflow into the auxiliary holes during the printing of several auxiliary layers includes: After each or more of the auxiliary layers are printed, airflow is supplied to the plurality of auxiliary holes after the formed workpiece leaves the liquid surface of the printing material; and before the formed workpiece enters the storage tank of the printing material to print the next target layer, the supply of airflow to the plurality of auxiliary holes is stopped.

11. The method as described in claim 8, characterized in that, The step of providing airflow to the auxiliary holes during the printing of the auxiliary layers includes: At the start of the exposure process corresponding to the current auxiliary layer, airflow is provided to the plurality of auxiliary holes; and, When the exposure process corresponding to the current auxiliary layer ends and the material moves a predetermined distance away from the bottom of the printing material storage tank, the airflow to the auxiliary holes is stopped.

12. The method as described in claim 1, characterized in that, The auxiliary holes in the auxiliary layers are connected to form a conical channel, and the diameter of the conical channel decreases sequentially according to the printing order.

13. The method as described in claim 1, characterized in that, The printing material for printing the auxiliary layers is liquid photosensitive resin or ceramic paste.

14. The method as described in claim 1, characterized in that, The printing material used to print the target layers is a ceramic slurry.

15. The method as described in claim 1, characterized in that, The pore size ranges from 2 to 100 micrometers.

16. A photopolymerization 3D printing system, characterized in that, include: A printing platform includes a cavity and a support plate. The support plate has several through holes communicating with the cavity and is used to support the formed workpiece. An exposure device is disposed opposite to the bottom of the cavity and is used to expose the printing material on the carrier plate; A lifting mechanism, connected to the support plate, is used to drive the support plate to move up and down; An airflow supply device, connected to the cavity for ventilation, is used to provide airflow into the cavity; The controller is configured to control the lifting mechanism, the exposure device, and the gas supply device to print a shaped workpiece including microholes, the microholes corresponding to at least one target through hole among the plurality of through holes, according to the method of any one of claims 1-15.

17. The photopolymerization 3D printing system as described in claim 16, characterized in that, The printing platform also includes a housing, the cavity is formed by the housing and the support plate, the air supply device includes an air pipe, the housing has an air pipe interface, and the air pipe is connected to the air pipe interface.

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