Three-dimensional model printing method and apparatus, and electronic device and readable storage medium

Abstract

The embodiments of the present disclosure relate to a three-dimensional model printing method and apparatus, and an electronic device. The method comprises: acquiring three-dimensional model data; determining cavity data from the three-dimensional model data; and on the basis of the cavity data, scheduling a corresponding printing strategy to perform printing, wherein the printing strategy comprises at least one of the following: adjusting a liquid level, controlling a waiting time, controlling a liquid discharging height, controlling motion parameters of a forming platform, adjusting an exposure strategy, and adjusting image data corresponding to a cavity. By means of the embodiments of the present disclosure, a printing mode is adaptively and automatically adjusted on the basis of a slice structure of a model without requiring a user to change the structure of the model, nor adjust the placement orientation of the model nor modify printing parameters, such that edge defects of a model with a cavity structure can be prevented from being printed, thereby improving the printing quality, and the printing efficiency can also be improved.

Description

Three-dimensional model printing method, device, electronic device and readable storage medium

[0001] Related Application

[0002] This disclosure claims priority to the Chinese patent application filed with the China Patent Office on February 8, 2024, with application number 202410177034.1 and invention name “Three-dimensional model printing method, device, electronic device and readable storage medium”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present disclosure relates to the field of 3D printing technology, and in particular to a three-dimensional model printing method, device, electronic device, and computer-readable storage medium. Background Art

[0004] In stereolithography 3D printing, the presence of a cavity (or inverted cup) in a printed part can affect print quality, leading to poor surface quality or even damage. As shown in Figure 1, if the printed portion of a 3D model includes an inverted cup structure, during the printing process, the printed part adheres layer by layer to the build platform. After each layer is printed, the build platform first rises, then descends, and contacts the resin 01 liquid surface. The cavity of the printed part and the tray molding area form a closed cavity. As the printed part descends, the gas in the cavity compresses the liquid below to flow outward. When the printed part descends to a thickness of one layer from the tray molding area, it begins to be exposed. At this point, some liquid still flows outward, forming an incompletely solidified material, which in turn produces a large amount of residue 02, resulting in defects on the printed part's surface.

[0005] For this type of problem, the commonly used solution is to change the design of the original three-dimensional model, such as opening holes in the closed cavity of the model to allow the liquid in the cavity to be discharged; or changing the placement of the model to avoid forming a closed cavity; or after identifying the existence of a cavity in the model, the entire model is printed at a low printing speed to avoid quality defects in the printed cavity part.

[0006] The above methods require a certain level of familiarity and experience with stereolithography 3D printing, and they also present certain challenges. For example, opening holes can disrupt the original model structure, changing the model's orientation adds additional supports, increasing printing material consumption, and not necessarily completely avoiding the inverted cup-shaped structure. Printing the entire model at a low print speed can significantly impact print time and efficiency.

[0007] In summary, since the industry solutions to this problem have certain technical barriers and defects, most users are aware of the problem but cannot solve it. Users who know the above industry solutions need to spend a lot of time to adjust the model structure, which results in excessively long printing times, greatly reducing the convenience of printing. Summary of the Invention

[0008] In view of this, in order to solve some or all of the above technical problems, the embodiments of the present disclosure provide a three-dimensional model printing method, device, electronic device and computer-readable storage medium.

[0009] In a first aspect, an embodiment of the present disclosure provides a three-dimensional model printing method, which is applied to a 3D printing device, the 3D printing device including a forming platform, and the method includes: obtaining three-dimensional model data; determining cavity data from the three-dimensional model data; and scheduling a corresponding printing strategy based on the cavity data for printing; wherein the printing strategy includes at least one of adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the forming platform, adjusting the exposure strategy, and adjusting the image data corresponding to the cavity.

[0010] In one possible embodiment, a corresponding printing strategy is scheduled according to the cavity data for printing, including: determining the cavity part and the non-cavity part of the three-dimensional model based on the cavity data; scheduling the corresponding cavity printing strategy for printing the cavity part, and scheduling the corresponding non-cavity printing strategy for printing the non-cavity part.

[0011] In one possible embodiment, determining cavity data from three-dimensional model data includes: identifying the entire three-dimensional model to obtain three-dimensional data, wherein the three-dimensional data includes at least one of the following: model three-dimensional position information, model shape, model volume, model wall thickness, and the number of sub-models; determining cavity data from the three-dimensional data, wherein the cavity data includes at least one of the following: cavity three-dimensional position information, cavity shape, cavity volume, cavity wall thickness, and the number of cavities; and / or slicing the three-dimensional model and identifying the slices where the cavities in the three-dimensional model are located as a cavity slice set; identifying each layer of slices in the cavity slice set to obtain cavity data, wherein the cavity data includes: at least one data of the area, position, shape, wall thickness, and number of the slice cross section, and at least one data of the area, position, shape, wall thickness, and number of the cavities in the slice cross section.

[0012] In one possible embodiment, each slice layer in the cavity slice set is identified to obtain cavity data, including: generating a two-dimensional slice image of each slice layer in the slice set to obtain a two-dimensional slice image set; determining cross-sectional geometric information of each two-dimensional slice image in the two-dimensional slice image set; and determining the cavity data based on the cross-sectional geometric information.

[0013] In one possible embodiment, a corresponding cavity printing strategy is scheduled based on the cavity data for printing, including: determining a subset of cavity images corresponding to the cavity area from a set of two-dimensional slice images based on cross-sectional geometric information; for each cavity image in the cavity image subset, determining whether the cavity image meets the optimized printing conditions based on the cross-sectional geometric information of the cavity image; if the optimized printing conditions are met, determining a target cavity printing strategy corresponding to the cavity image, and printing the three-dimensional model slice corresponding to the cavity image based on the target cavity printing strategy.

[0014] In one possible embodiment, based on cross-sectional geometric information, a subset of cavity images corresponding to the cavity area is determined from a set of two-dimensional slice images, including: for each two-dimensional slice image in the set of two-dimensional slice images, based on the cross-sectional geometric information of the two-dimensional slice image, determining the difference between the cavity area in the two-dimensional slice image and the cavity area in the previous two-dimensional slice image; if the difference meets the cavity determination condition and it is determined that the two-dimensional slice image contains a through hole, determining the size of the through hole; if the size of the through hole is less than or equal to a preset size, determining that the two-dimensional slice image is a cavity image.

[0015] In one possible embodiment, determining whether the cavity image meets the optimized printing conditions based on the cross-sectional geometric information of the cavity image includes: determining the ratio of the cavity area to the cross-sectional area of ​​the cavity image based on the cross-sectional geometric information of the cavity image; if the ratio is greater than or equal to a preset ratio threshold, determining the cavity printing difficulty value of the cavity image based on the cross-sectional geometric information of the cavity image; if the cavity printing difficulty value is greater than or equal to the preset difficulty threshold, determining that the cavity image meets the optimized printing conditions.

[0016] In one possible embodiment, after determining the ratio of the cavity area to the cross-sectional area of ​​the cavity image based on the cross-sectional geometric information of the cavity image, the method further includes: if the ratio is less than a preset ratio threshold, determining that the cavity image does not meet the optimized printing conditions.

[0017] In one possible embodiment, determining the cavity printing difficulty value of the cavity image based on the cross-sectional geometric information of the cavity image includes: determining the cavity degree value of the cavity image based on the cross-sectional geometric information of the cavity image; obtaining material parameters of the printing material of the three-dimensional model; and determining the cavity printing difficulty value of the cavity image based on the cavity degree value and the material parameters.

[0018] In one possible embodiment, determining the cavity degree value of the cavity image based on the cross-sectional geometric information of the cavity image includes: calculating the cavity degree value of the cavity image based on at least one of the cavity wall thickness, cavity number, cavity area, cavity shape and influencing factors between cavities included in the cross-sectional geometric information of the cavity image.

[0019] In one possible embodiment, determining the target cavity printing strategy corresponding to the cavity image includes: based on the correspondence between the preset cavity printing strategy and the cavity printing difficulty value, determining at least one cavity printing strategy corresponding to the cavity printing difficulty value of the cavity image as the target cavity printing strategy from at least two cavity printing strategies included in the preset cavity printing strategy.

[0020] In one possible embodiment, the 3D printing device further includes a material tray, and the at least two cavity printing strategies include at least two of the following: Method 1, when the liquid level of the printing material is lower than a preset height, the liquid replenishing device is controlled to replenish the printing material to the material tray so that the liquid level of the printing material remains higher than the rising height of the forming platform; Method 2, when the forming platform descends, when the layer thickness is a first preset multiple from the bottom of the material tray, the forming platform is controlled to stop moving, and after waiting for a first preset time, the forming platform is controlled to continue to descend to a layer thickness of a second preset multiple from the bottom of the material tray, and the printing operation is started, wherein the first preset multiple is greater than the second preset multiple; Method 3, when the forming platform descends to a layer thickness of a third preset multiple from the bottom of the material tray, the forming platform is controlled to stop moving, and after waiting for a second preset time, the forming platform is controlled to rise to a layer thickness of a second preset multiple from the bottom of the material tray, and the printing operation is started, wherein the third preset multiple is less than the second preset multiple; Method 4, when the forming platform descends to a layer thickness of a second preset multiple from the bottom of the material tray, the forming platform is controlled to stop moving, and after waiting for the third preset time, the printing operation is started.

[0021] In one possible embodiment, the 3D printing device further includes a material tray, and the at least two cavity printing strategies include the following two:

[0022] Mode 5: When the build platform descends, when the layer thickness reaches a first preset multiple from the liquid level at the top of the tray, the build platform is controlled to stop moving. After waiting for a first preset time, the build platform is controlled to continue descending until the layer thickness reaches a second preset multiple from the liquid level at the top of the tray, and the printing operation is started. The first preset multiple is less than the second preset multiple.

[0023] Method six: When the forming platform descends to a layer thickness that is a third preset multiple of the liquid level at the top of the material tray, the forming platform is controlled to stop moving. After waiting for a second preset time, the forming platform is controlled to rise to a layer thickness that is a second preset multiple of the liquid level at the top of the material tray, and the printing operation is started, wherein the third preset multiple is greater than the second preset multiple.

[0024] In one possible embodiment, a target cavity printing strategy corresponding to the cavity image is determined, and based on the target cavity printing strategy, a three-dimensional model slice corresponding to the cavity image is printed, including: if the wall thickness of the closed cavity in the cavity image is greater than or equal to a preset wall thickness, the closed cavity wall in the cavity image is split into a filling area and a contour area, and the filling area and the contour area are printed in sequence.

[0025] In a second aspect, an embodiment of the present disclosure provides a three-dimensional model printing device, which is applied to a 3D printing device. The 3D printing device includes a forming platform. The device includes: an acquisition unit, configured to acquire three-dimensional model data; a first determination unit, configured to determine cavity data from the three-dimensional model data; a printing unit, configured to schedule a corresponding printing strategy based on the cavity data for printing; wherein the printing strategy includes at least one of adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the forming platform, adjusting the exposure strategy, and adjusting the image data corresponding to the cavity.

[0026] In a third aspect, an embodiment of the present disclosure provides an electronic device, comprising: a memory for storing a computer program; a processor for executing the computer program stored in the memory, and when the computer program is executed, implementing the method of any embodiment of the three-dimensional model printing method of the first aspect of the present disclosure.

[0027] In a fourth aspect, an embodiment of the present disclosure provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method of any embodiment of the three-dimensional model printing method of the first aspect described above is implemented.

[0028] In a fifth aspect, an embodiment of the present disclosure provides a computer program, which includes a computer-readable code. When the computer-readable code runs on a device, the processor in the device implements a method as in any embodiment of the three-dimensional model printing method of the first aspect mentioned above.

[0029] The present disclosure provides a three-dimensional printing method, which includes: forming at least one base layer on a forming platform of a printing device; according to an adjusted printing strategy, using a light source mechanism of the printing device to project light onto a photosensitive material to solidify the photosensitive material and form a target layer on a construction surface of the printing device, wherein the target layer adheres to the at least one base layer, and the target layer includes an unfilled portion and a filled portion that completely surrounds the unfilled portion, wherein the at least one base layer and the target layer jointly define a cavity; wherein the adjusted printing strategy includes at least one of adjusting a liquid level, controlling a waiting time, controlling a liquid discharge height, controlling forming platform motion parameters, adjusting an exposure strategy, and adjusting image data corresponding to the cavity.

[0030] In some embodiments, adjusting the liquid level includes supplying printing material to a material tray of a printing device so that air does not enter the cavity area of ​​the model.

[0031] In some embodiments, controlling the waiting time includes: controlling the forming platform carrying the at least one base layer to move to a predetermined distance from the construction surface and then to remain stationary for a predetermined time.

[0032] In some embodiments, controlling the drainage height includes controlling the forming platform carrying the at least one base layer to move to a predetermined distance from the building surface.

[0033] In some embodiments, controlling the motion parameters of the building platform includes adjusting at least one of a motion speed and a motion distance of the building platform.

[0034] In some embodiments, adjusting the exposure strategy includes at least one of: exposing in different regions and extending the exposure time.

[0035] In some embodiments, adjusting the image data corresponding to the cavity includes dividing the slice image and dividing the printing section into multiple parts for sequential printing.

[0036] In some embodiments, at least one base layer includes a cover layer adhered to the target layer, the cover layer covering or masking unfilled portions of the target layer.

[0037] In some embodiments, at least one base layer includes a covering layer and at least one intermediate layer, the at least one intermediate layer is adhered to the target layer and the covering layer, wherein the at least one intermediate layer includes an unfilled portion and a filled portion that completely surrounds the unfilled portion, the covering layer covers or shields the unfilled portion of the at least one intermediate layer, and the unfilled portion of the at least one intermediate layer is connected to the unfilled portion of the target layer.

[0038] In some embodiments, at least one base layer, a target layer on the build surface, and the build surface collectively define a cavity.

[0039] In some embodiments, the construction surface is defined by a film.

[0040] In some embodiments, the parameters of the adjusted printing strategy are determined based on at least one of the following: cavity wall thickness, number of cavities, cavity area, and cavity shape.

[0041] In some embodiments, the adjusted printing strategy includes: lowering the building platform to a predetermined position, where the distance between the predetermined position and the construction surface is greater than or less than the thickness of the target layer; allowing the building platform to stay at the predetermined position for a preset period of time; moving the building platform from the predetermined position to a printing position, where the distance between the printing position and the construction surface is the thickness of the target layer; and causing the light source mechanism to project light to form the target layer.

[0042] In some embodiments, the adjusted printing strategy includes: moving the build platform to a printing position, where the distance between the printing position and the construction surface is the thickness of the target layer; allowing the build platform to stay at the printing position for a preset time; and allowing the light source mechanism to project light to form the target layer.

[0043] In some embodiments, the preset time period is determined based on a change in force detected by a force sensor mounted on the building platform.

[0044] The three-dimensional model printing method, device, electronic device and computer-readable storage medium provided by the embodiments of the present disclosure determine cavity data from the three-dimensional model data to be printed, and schedule a corresponding printing strategy for printing based on the cavity data, wherein the printing strategy includes adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the forming platform, adjusting the exposure strategy, and adjusting at least one of the image data corresponding to the cavity. This achieves that the user does not need to change the model structure, adjust the model's placement posture, or modify the printing parameters. The printing method is automatically adjusted according to the slicing structure of the model, which can avoid edge defects of the model with a printed cavity structure, improve the printing quality, and improve the printing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0046] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0047] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0048] FIG1 is a schematic diagram of the printing process of a closed cavity;

[0049] FIG2 is a schematic diagram of an optional 3D printing device provided in an embodiment of the present disclosure;

[0050] FIG3 is a schematic diagram of another optional 3D printing device provided in an embodiment of the present disclosure;

[0051] 4A-4B are schematic diagrams of slices of a three-dimensional model forming a closed cavity provided by an embodiment of the present disclosure.

[0052] 4C-4F are schematic structural diagrams of a three-dimensional model for forming a closed cavity provided by an embodiment of the present disclosure;

[0053] FIG5 is a schematic diagram of a flow chart of a three-dimensional model printing method provided in an embodiment of the present disclosure;

[0054] FIG6 is a schematic flow chart of another three-dimensional model printing method provided by an embodiment of the present disclosure;

[0055] FIG7A is a schematic structural diagram of a three-dimensional model for forming a cavity during printing provided by an embodiment of the present disclosure;

[0056] FIG7B is a schematic diagram of a cavity image provided by an embodiment of the present disclosure;

[0057] FIG8 is a schematic flow chart of another three-dimensional model printing method provided by an embodiment of the present disclosure;

[0058] FIG9 is a schematic structural diagram of a three-dimensional model including a relatively small through hole provided by an embodiment of the present disclosure;

[0059] FIG10 is a schematic diagram of a flow chart of another three-dimensional model printing method provided in an embodiment of the present disclosure;

[0060] FIG11 is a schematic flow chart of another three-dimensional model printing method provided in an embodiment of the present disclosure;

[0061] FIG12 is a schematic diagram of a slice of a three-dimensional model provided by an embodiment of the present disclosure;

[0062] FIG13A is a schematic diagram of an image of a cavity with a relatively large wall thickness provided by an embodiment of the present disclosure;

[0063] FIG13B is a schematic diagram of a split filling area image provided by an embodiment of the present disclosure;

[0064] FIG13C is a schematic diagram of a split contour area image provided by an embodiment of the present disclosure;

[0065] FIG14 is a schematic structural diagram of a three-dimensional model printing device provided by an embodiment of the present disclosure;

[0066] FIG15 is a schematic structural diagram of an electronic device provided by an embodiment of the present disclosure;

[0067] 16A-16D illustrate an embodiment of adjusting the liquid level;

[0068] 17A-17B illustrate an embodiment of zoned exposure.

[0069] In the drawings, the same or similar numerals represent the same or similar elements or parts.

[0070] The accompanying drawings are numbered as follows: 01, resin; 02, residue; 11, molding platform; 12, material tray; 13, light source mechanism; 14, print part; 15, resin liquid level; 16, molding area; 17, construction surface; 1001, acquisition component; 1002, first determination component; 1003, printing component; 1100, electronic device; 1101, processor; 1102, memory; 11021, operating system; 11022, application; 1103, user interface; 1104, network interface; 1105, bus system. DETAILED DESCRIPTION

[0071] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It is apparent that the described embodiments are only a portion of the embodiments of the present disclosure, rather than all of the embodiments. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions, and numerical values ​​described in these embodiments do not limit the scope of the present disclosure.

[0072] Those skilled in the art will understand that the terms "first" and "second" in the embodiments of the present disclosure are only used to distinguish objects such as different steps, devices or components, and neither represent any specific technical meaning nor indicate the logical order between them.

[0073] It should also be understood that in this embodiment, “a plurality of” may refer to two or more than two, and “at least one” may refer to one, two or more than two.

[0074] It should also be understood that any component, data or structure mentioned in the embodiments of the present disclosure can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0075] In addition, the term "and / or" in this disclosure is merely a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this disclosure generally indicates that the related objects are in an "or" relationship.

[0076] It should also be understood that the description of the various embodiments in this disclosure focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced with each other. For the sake of brevity, they will not be described one by one.

[0077] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0078] Technologies, circuits, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the above-mentioned technologies, circuits, and devices should be considered part of the specification.

[0079] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0080] It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other. To facilitate understanding of the embodiments of the present disclosure, the present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments. Obviously, the embodiments described are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0081] In order to solve the technical problem of poor quality of printing models with closed cavity structures in the prior art, the present disclosure provides a three-dimensional model printing method, which can adaptively adjust the printing method for models with closed cavity structures, thereby improving printing quality and printing efficiency.

[0082] Figure 5 is a flow chart of a three-dimensional model printing method provided by an embodiment of the present disclosure. This method can be applied to a 3D printing device, which includes a molding platform. The execution subject of this method can be a 3D printing device, or it can be one or more electronic devices such as a laptop computer, a desktop computer, a portable computer, a server, etc. These electronic devices can be connected to the 3D printing device in communication to execute the method and control the 3D printing device to print. In addition, the execution subject of this method can be hardware or software. When the above-mentioned execution subject is hardware, the execution subject can be one or more of the above-mentioned electronic devices. For example, a single electronic device can execute this method, or multiple electronic devices can cooperate with each other to execute this method. When the above-mentioned execution subject is software, this method can be implemented as multiple software or software modules, or it can be implemented as a single software or software module. No specific limitation is made here.

[0083] When performing 3D printing, a 3D model of the printout can be created first, and then the 3D model of the printout can be sliced ​​layer by layer. Printing can start with the first sliced ​​model, and based on the previously successfully printed sliced ​​model, each sliced ​​model is printed in sequence, ultimately obtaining a complete 3D model of the printout. The printout is the object being printed in 3D printing. Figure 2 is a schematic diagram of an optional 3D printing device provided according to an embodiment of the present disclosure, commonly referred to as a bottom projection technique. As shown in FIG2 , an optional 3D printing device provided in an embodiment of the present disclosure can generate a projected image based on the shape of each sliced ​​model layer when printing the sliced ​​model layer, and send the projected image to a light source mechanism 13, such as an optical machine, LCD, etc., which is a light source device. The light source mechanism 13 can project the projected image onto a molding area 16 within a tray 12 filled with a polymerizable liquid (such as a photosensitive material), that is, onto a building surface 17, i.e., the surface of the bottom of the tray that contacts the resin. The polymerizable liquid on the molding area will be irradiated by the light emitted by the light source mechanism 13 and solidify between the molding platform 11 and the building surface 17 to form a solid or semi-solid polymer. At this time, the molding platform 11 can be controlled to move so that the solid or semi-solid polymer separates from the building surface 17 layer by layer. This layer-by-layer solidification-separation-curing-separation cycle is repeated to ultimately form a model matching the projected image, i.e., a printed part 14. The building surface 17 can be defined by a film of the tray 12, such as an FEP film.

[0084] FIG3 is a schematic diagram of another optional 3D printing device provided according to an embodiment of the present disclosure, which is generally referred to as top projection technology. As shown in FIG3 , the optional 3D printing device provided by the embodiment of the present disclosure can generate a projection image according to the shape of each slice model layer when printing the slice model layer, and send the projection image to a light source mechanism 13, such as an optical machine, and the light source mechanism is a light source device; the light source mechanism 13 can project the projection image onto a molding area 16 in a material tray 12 filled with a polymerizable liquid (such as a photosensitive material), that is, onto a construction surface 17, that is, the surface of the resin on the top of the material tray. The polymerizable liquid on the molding area 16 will be irradiated by the light emitted by the light source mechanism 13 and solidified between the molding platform 11 and the construction surface 17 to form a solid or semi-solid polymer. At this time, the molding platform 11 can be controlled to move so that the solid or semi-solid polymer is separated from the construction surface layer by layer. The process of curing-separating-curing-separating layer by layer is repeated to finally form a model matching the projection image, that is, a printed part 14.

[0085] The cavity mentioned in the embodiments of the present disclosure refers to a cavity in a three-dimensional model (three-dimensional object), such as a vase, bowl, cup, dental mold, spare parts, toy, headphone shell, etc. These objects have cavities inside, and their three-dimensional models must also have cavities. In the 3D printing process, the three-dimensional model of the three-dimensional object is first sliced ​​to obtain a collection of slices, and then the slices are printed layer by layer to complete the 3D printing. In the three-dimensional model, if the nth layer of the slice is a complete solid cross-section, and the wall cross-section from the n+1th layer to the n+mth layer is an annular wall cross-section, then it is determined that there is a cavity at this time. The solid cross-section of the nth layer, the wall cross-section of the n+mth layer, and the structural surface of the molding area form a closed cavity, which will cause the resin inside the cavity to be unable to be removed during the printing process, or the gas in the cavity will compress the liquid below to flow around. When the next layer begins to be exposed, some liquid still flows around to form an incompletely solidified object, which in turn produces a large amount of residue, resulting in defects on the surface of the printed part, and may also cause the printed part to warp.

[0086] Figures 4A-4F are schematic diagrams of the structure of a three-dimensional model forming a cavity according to an embodiment of the present disclosure. As shown in Figure 4A, the nth layer is a complete solid cross-section, and from the n+1th layer to the n+mth layer, it is an annular wall cross-section. At the n+m+1th layer, it is a complete solid cross-section again. At this time, the three-dimensional model is a model with a closed cavity inside, such as a hollow sphere model. As shown in Figure 4B, the nth layer is a complete solid cross-section, and from the n+1th layer to the n+mth layer, it is an annular wall cross-section. At this time, the three-dimensional model is an open cavity, such as a water cup, a vase, etc. For this type of model, a closed cavity is formed by the bottom wall, side walls, and structural surfaces of the molding area of ​​the model, that is, a closed cavity.

[0087] As shown in Figures 4C-4F, A1, A2, A3, B1, B2, B3, and C1 are cavity areas. A 3D model may contain one or multiple cavities. The position, shape, volume, wall thickness, and number of cavities may be the same or different. The number of slice layers in which the cavities are located, as well as the area, position, shape, wall thickness, and number of slice cross-sections of each slice layer containing cavities, may be the same or different. Furthermore, the area, position, shape, wall thickness, and number of cavities in a slice cross-section may be the same or different. Therefore, it is necessary to identify cavity information in order to schedule the corresponding printing strategy.

[0088] At least one base layer is formed on the forming platform 11 of the printing device (for example, one or more solidified layers close to the forming platform 11 in FIG. 4C ); according to the adjusted printing strategy, a light source mechanism of the printing device is used to project light onto the photosensitive material to solidify the photosensitive material and form a target layer (for example, the layer to be solidified away from the forming platform 11 in FIG. 4C ) on the construction surface of the printing device, wherein the target layer adheres to the at least one base layer, and the target layer includes an unfilled portion (i.e., a portion of the cavity) and a filled portion that completely surrounds the unfilled portion (i.e., a portion of the wall defining the cavity), wherein the at least one base layer and the target layer jointly define a cavity A2; wherein the adjusted printing strategy includes at least one of adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the forming platform motion parameters, adjusting the exposure strategy, and adjusting the image data corresponding to the cavity.

[0089] As shown in FIG5 , the method specifically includes:

[0090] Step 201: Acquire three-dimensional model data.

[0091] In this embodiment, the three-dimensional model data refers to various data of the three-dimensional model to be printed by the 3D printing device, for example, it may include data such as the size, wall thickness, and position of the three-dimensional model.

[0092] Step 202: Determine cavity data from the three-dimensional model data.

[0093] In this embodiment, the cavity data refers to data related to the cavity in the three-dimensional model, for example, the cavity data includes data such as the position, shape, wall thickness, and number of cavities.

[0094] Step 203: dispatching a corresponding printing strategy according to the cavity data to perform printing.

[0095] In this embodiment, the printing strategy includes at least one of adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the molding platform, adjusting the exposure strategy, and adjusting the image data corresponding to the cavity.

[0096] Specifically, when the three-dimensional model includes a cavity area, the printing process of the cavity area will have the problems described in the background technology. Therefore, a printing strategy can be set for the cavity area. Among them, the above-mentioned adjustment of the liquid level refers to timely replenishing the liquid printing material in the material tray so that the cavity area of ​​the model does not enter the air. As shown in Figures 2 and 3, as printing proceeds, the printing material (such as resin) is continuously consumed, and the resin liquid level 15 will drop. It is necessary to replenish the printing material in time so that the liquid level remains at a certain height to prevent the cavity area of ​​the model from entering the air; the above-mentioned control of the waiting time refers to controlling the molding platform to carry the bottom (or top) of the printed part to descend / rise to a certain distance from the molding area, waiting for a period of time to stop the liquid flow and stabilize the resin in the molding area; the distance between the bottom (or top) of the printed part and the molding area during the above-mentioned waiting time is the discharge height; the above-mentioned molding platform motion parameters include parameters such as motion speed and motion distance; the above-mentioned exposure strategy includes regional exposure, different exposure times, etc.; the above-mentioned adjustment of the image data corresponding to the cavity refers to dividing the slice image, dividing the printed section into multiple parts and printing them in sequence to eliminate defects at the edge of the cavity.

[0097] As an example, a printing strategy may include: controlling the build platform to stop when it descends to 1 times the layer thickness from the bottom (or top) of the material tray, waiting for a certain period of time (e.g., 10 seconds) until the liquid stops flowing, and then resuming printing in a conventional manner. Another example may include controlling the rehydration device to ensure that the liquid level of the liquid printing material in the material tray is higher than a preset height to ensure that no air enters the enclosed cavity during printing.

[0098] It should be noted that the above-mentioned printing strategy can be applied to the entire three-dimensional model, that is, the same strategy is adopted when printing the entire three-dimensional model to eliminate printing defects caused by closed cavities; different printing strategies can also be set for different parts of the three-dimensional model, for example, a cavity-specific printing strategy is set for the cavity part, and a conventional printing strategy is adopted for the non-cavity part.

[0099] The three-dimensional model printing method provided by the embodiment of the present disclosure determines cavity data from the three-dimensional model data to be printed, and schedules a corresponding printing strategy for printing based on the cavity data, wherein the printing strategy includes adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the forming platform, adjusting the exposure strategy, and adjusting at least one of the image data corresponding to the cavity. This method does not require the user to change the model structure, adjust the model's placement posture, or modify the printing parameters. The printing method is automatically adjusted according to the slicing structure of the model, which can avoid edge defects of the model with a printed cavity structure, improve the printing quality, and improve the printing efficiency.

[0100] In some optional implementations of this embodiment, as shown in FIG6 , step 203 includes:

[0101] Step 2031: Determine the cavity part and the non-cavity part of the three-dimensional model based on the cavity data.

[0102] The cavity portion of the 3D model refers to the portion of the printed material forming area where a closed cavity appears between the surface of the printed part and the printed part during the printing process, while the remaining portion refers to the non-cavity portion. The electronic device can horizontally slice the 3D model based on the cavity structural characteristics represented by the cavity data. The sliced ​​cross-sections are the boundaries between the cavity portion and the non-cavity portion. It should be understood that the number of cavity portions and non-cavity portions can be at least one.

[0103] Step 2032: For the cavity portion, a corresponding cavity printing strategy is scheduled to print; for the non-cavity portion, a corresponding non-cavity printing strategy is scheduled to print.

[0104] The cavity printing strategy may include at least one of the following strategies for the cavity portion: adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the build platform, adjusting the exposure strategy, adjusting the image data corresponding to the cavity, etc. The non-cavity printing strategy may include at least one of the following strategies for the non-cavity portion: adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the build platform, adjusting the exposure strategy, adjusting the image data corresponding to the cavity, etc.

[0105] For example, for the cavity part, you can set a longer drainage wait time, a higher drainage height, divide the slice image data into the fill area and the outline area and print them in sequence, etc. For the non-cavity part, you can set a shorter drainage time, a lower drainage height, and print directly without adjusting the slice image.

[0106] This embodiment sets a cavity printing strategy and a non-cavity printing strategy to implement a targeted execution of the cavity printing strategy for the cavity part of the three-dimensional model to eliminate printing defects caused by closed cavities formed during printing, and implements a non-cavity printing strategy for the non-cavity part to increase the printing speed, thereby taking into account both printing quality and printing efficiency.

[0107] In some optional implementations of this embodiment, step 202 may include at least one of the following two implementations:

[0108] Method 1: First, the entire three-dimensional model is identified to obtain three-dimensional data.

[0109] The three-dimensional data includes at least one of the following: model three-dimensional position information, model shape, model volume, model wall thickness, and the number of sub-models. The number of sub-models refers to the number of sub-models included in the entire three-dimensional model. The model three-dimensional position information includes information such as the three-dimensional coordinates of each component of the model. The model shape can be represented by the coordinates of each point on the model's outline. The model wall thickness refers to the wall thickness of each component of the model. The model volume refers to the overall volume of the model and the volume of each component of the model.

[0110] Then, cavity data is determined from the three-dimensional data.

[0111] The cavity data includes at least one of the following: three-dimensional cavity position information, cavity shape, cavity volume, cavity wall thickness, and number of cavities. Specifically, the electronic device can analyze the three-dimensional data of the entire model to determine relevant data about cavities isolated from the outside world. Alternatively, a through-hole size threshold can be set to identify, from among the non-enclosed cavities, cavities containing through-holes smaller than the through-hole size threshold as closed cavities.

[0112] The three-dimensional model is sliced, and the slices where the cavities in the three-dimensional model are located are identified as a cavity slice set; each layer of slices in the cavity slice set is identified to obtain cavity data, wherein the cavity data includes: at least one data of the area, position, shape, wall thickness, and number of the slice cross section, and at least one data of the area, position, shape, wall thickness, and number of the cavities in the slice cross section.

[0113] Method 2: First, the three-dimensional model is sliced, and the slices where the cavities in the three-dimensional model are located are identified as a cavity slice set.

[0114] Specifically, the slice thickness can be pre-set, and the three-dimensional model can be sliced ​​according to the slice thickness to obtain a slice set. According to the three-dimensional position information of the cavity, the slices that coincide with the cavity position are determined from the slice set as the cavity slice set.

[0115] Then, each slice in the cavity slice set is identified to obtain cavity data.

[0116] The cavity data includes at least one of the area, position, shape, wall thickness and number of the slice cross section, and at least one of the area, position, shape, wall thickness and number of the cavity in the slice cross section.

[0117] This embodiment provides two methods for determining cavity data, enabling identification of cavities as a whole or based on slices, thereby improving the accuracy of determining enclosed cavity areas. These two methods can be used simultaneously or separately, and the specific method can be adapted based on the actual application and scenario.

[0118] In some optional implementations of this embodiment, as shown in FIG6 , in the above-mentioned second method, each slice in the cavity slice set may be identified according to the following steps to obtain cavity data:

[0119] Step 2021 : Generate a two-dimensional slice image of each slice in the slice set to obtain a two-dimensional slice image set.

[0120] In this embodiment, the electronic device can import a 3D model of an object that the user wants to print and slice the 3D model. Specifically, the slice thickness can be pre-set, and the 3D model is sliced ​​according to the slice thickness. The cross-sectional image of each slice is the corresponding 2D slice image.

[0121] Step 2022: Determine cross-sectional geometric information of each two-dimensional slice image in the two-dimensional slice image set.

[0122] In this embodiment, the electronic device can identify the two-dimensional slice image of each slice layer and determine the geometric information of the cross-sectional contour of the three-dimensional model. The cross-sectional geometric information may include the area, position, shape, cavity wall thickness, etc. of the cross section.

[0123] Step 2023: Determine cavity data based on the cross-sectional geometric information.

[0124] The cross-sectional geometric information can represent geometric features of the cavity. Therefore, data representing the cavity can be extracted from the cross-sectional geometric information as cavity data. The cavity data can include but is not limited to at least one of the following: cavity shape, number of cavities, cavity wall thickness, etc.

[0125] This embodiment determines the cross-sectional geometric information of each two-dimensional slice image and determines the cavity data based on the cross-sectional geometric information, thereby realizing two-dimensional geometric features based on the cavity. The cavity data can be determined after slicing the model, which helps to improve the efficiency of determining the cavity data.

[0126] In some optional implementations of this embodiment, as shown in FIG6 , step 203 includes:

[0127] Step 2031 : determining a cavity image subset corresponding to the cavity region from the two-dimensional slice image set based on the cross-sectional geometric information.

[0128] In this embodiment, the electronic device can determine, from the set of two-dimensional slice images, a plurality of two-dimensional slice images corresponding to the closed cavity area as a cavity image subset based on the geometric characteristics of the cavity. As shown in FIG7A , three models are printed at the same time and are sliced ​​into 2000 layers, i.e., 2000 two-dimensional slice images are obtained. Two of the models (181 and 182) include a cavity layer, i.e., an inverted cup mouth layer. When the lower end of the inverted cup mouth layer contacts the liquid surface in the tray, a closed cavity area is formed. The other model does not include an inverted cup mouth layer because it has an opening at the top, i.e., the model 183 without an inverted cup mouth layer in FIG7A . As shown in FIG7B , it shows the two-dimensional slice images corresponding to layers 127-954 of the three models. These images constitute a cavity image subset, corresponding to the closed cavity areas of the two models.

[0129] Step 2032: For each cavity image in the cavity image subset, determine whether the cavity image meets the optimized printing conditions based on the cross-sectional geometric information of the cavity image; if it meets the optimized printing conditions, determine the target cavity printing strategy corresponding to the cavity image, and print the three-dimensional model slice corresponding to the cavity image based on the target cavity printing strategy.

[0130] In this embodiment, the optimized printing condition may be a preset condition indicating that the printing strategy needs to be adjusted because the slice of the 3D model currently being printed contains a closed cavity. This means that even if the optimized printing condition is met, printing defects may occur due to the presence of the closed cavity. For example, the cross-section information may include information such as the cavity area and cavity wall thickness. If the cavity area is greater than a preset area and / or the cavity wall thickness is less than a preset wall thickness, the optimized printing condition is determined to be met.

[0131] When the printing optimization conditions are met, the target cavity printing strategy can be executed according to the preset printing parameters. For example, the target cavity printing strategy may include: controlling the molding platform to stop moving when it drops to 1 times the layer thickness from the bottom (or top) of the material tray, waiting for a certain period of time (for example, 10 seconds), and then printing in a conventional manner after the liquid stops flowing. For another example, the target cavity printing strategy may include: controlling the liquid replenishing device to make the liquid level of the liquid printing material in the material tray higher than the preset height to ensure that no air enters the closed cavity during printing.

[0132] It should be noted that step 2032 is performed for each cavity image in the cavity image subset, that is, the same steps are repeatedly performed for each cavity image, thereby completing the printing of the three-dimensional model slice corresponding to each cavity image.

[0133] It should be understood that if the cavity image does not meet the optimized printing conditions, the three-dimensional model slice corresponding to the cavity image is printed according to the conventional process.

[0134] This embodiment determines a subset of cavity images corresponding to a closed cavity area from a set of two-dimensional slice images, and then determines whether the cavity image meets the optimized printing conditions based on the cross-sectional geometric information of each cavity image. If so, a target cavity printing strategy corresponding to the cavity image is determined, and based on the target cavity printing strategy, the three-dimensional model slice corresponding to the cavity image is printed. This embodiment does not require the user to change the model structure, adjust the model's placement posture, or modify the printing parameters. The printing method is adaptively adjusted according to the slice structure of the model, which can avoid edge defects of the model with the printed cavity structure, improve printing quality, and improve printing efficiency.

[0135] In some optional implementations of this embodiment, as shown in FIG8 , step 2031 includes:

[0136] Step 20311 : for each 2D slice image in the 2D slice image set, determine the difference between the cavity area in the 2D slice image and the cavity area in the previous 2D slice image based on the cross-sectional geometric information of the 2D slice image.

[0137] Specifically, the cross-sectional information of the two-dimensional slice image may include information related to the cross-sectional contour. Based on this information, it can be determined whether the two-dimensional slice image includes a cavity (the included cavity is not necessarily a closed cavity, it may also be a through hole), and the cavity area can be determined. When the two-dimensional slice image includes multiple cavities, the cavity area can be the sum of the areas of the multiple cavities.

[0138] Step 20312: If the difference meets the cavity determination condition and it is determined that the two-dimensional slice image contains a through hole, the size of the through hole is determined.

[0139] The above cavity determination condition is to determine whether the current two-dimensional slice image corresponds to a closed cavity.

[0140] Optionally, the cavity determination condition may include: the difference being greater than or equal to a preset value. For example, if the cavity area changes from a value of 0 in the previous slice to a non-zero value in the current slice, a closed cavity is determined to be present, and the two-dimensional slice image corresponding to the slice is a cavity image.

[0141] Specifically, if a cavity appears in a 2D slice image, the cavity information of the slice before it can be used to determine whether it is a through hole. For example, if multiple cavities with overlapping areas appear continuously starting from the first slice, the cavity is determined to be a through hole. The size of the through hole can be determined based on the cross-sectional geometric information of each slice.

[0142] Step 20313: If the size of the through hole is smaller than or equal to the preset size, determine that the two-dimensional slice image is a cavity image.

[0143] When the size of the through-hole is smaller than or equal to the preset size, the exhaust velocity of the model after contacting the liquid surface is low, which still creates an effect similar to a closed cavity and affects the printing quality. Therefore, the two-dimensional slice image can be determined as a cavity image and printed according to the printing strategy for a closed cavity.

[0144] As shown in Figure 9, it shows a schematic diagram of a three-dimensional model. The part indicated by the rectangular box in the figure is a gap, which is equivalent to a through hole. Since the size of the gap is small, this part can be determined as a closed cavity area, and the two-dimensional slice image corresponding to this part is a cavity image.

[0145] This embodiment sets cavity determination conditions and determines whether a two-dimensional slice image is a cavity image based on the through-hole size. This fully considers the actual printing scenario based on the structural characteristics of the closed cavity, thereby improving the accuracy of determining the cavity image, and further making the printing strategy for the closed cavity more adapted to the actual printing scenario, thereby improving the printing quality.

[0146] In some optional implementations of this embodiment, as shown in FIG10 , in step 2032 , for each cavity image in the cavity image subset, the following steps may also be performed:

[0147] Step 20321: Determine the ratio of the cavity area to the cross-sectional area of ​​the cavity image based on the cross-sectional geometric information of the cavity image.

[0148] The cross-sectional area is the total area of ​​the cross-section of the three-dimensional model in the current slice, and the cavity area is the total area of ​​the closed region enclosed within the cross-section without openings.

[0149] Step 20322: If the ratio is greater than or equal to the preset ratio threshold, determine the cavity printing difficulty value of the cavity image based on the cross-sectional geometric information of the cavity image.

[0150] Among them, the cavity printing difficulty value is a quantitative reference parameter when printing a closed cavity area. The larger the cavity printing difficulty value, the greater the impact on the quality of the model molding when printing the cavity, and the greater the possibility of quality defects.

[0151] As an example, the printing difficulty value can be calculated based on parameters such as the cavity's area, location, shape, and wall thickness. For example, a weight can be assigned to each parameter, and the weighted sum of the parameters can be used to determine the printing difficulty value. Generally, the calculation method for the printing difficulty value follows the following rules: the larger the area of ​​the enclosed cavity, the greater the printing difficulty value; the smaller the minimum wall thickness of the enclosed cavity, the greater the printing difficulty value; and the closer the enclosed cavity is to other cross-sections, the greater the printing difficulty value.

[0152] Step 20323: If the cavity printing difficulty value is greater than or equal to the preset difficulty threshold, it is determined that the cavity image meets the optimized printing conditions.

[0153] Among them, the preset difficulty threshold can be pre-set according to the actual printing scenario. When the cavity printing difficulty value is greater than or equal to the preset difficulty threshold, it means that when printing in a conventional printing method at this time, the possibility of printing defects in the cavity area is greater, and it is necessary to set the target cavity printing strategy in a targeted manner (for example, increase the waiting time below the liquid level).

[0154] This embodiment quantifies the difficulty of printing a cavity by determining a cavity printing difficulty value when the ratio of the cavity area to the cross-sectional area is greater than a preset ratio threshold. The printing difficulty value can more accurately reflect the possibility of printing quality problems when printing a closed cavity, thereby enabling more targeted adjustments to the printing method and further improving the printing quality.

[0155] In some optional implementations of this embodiment, as shown in FIG10 , after step 20321, the method further includes:

[0156] Step 20324: If the ratio is less than the preset ratio threshold, it is determined that the cavity image does not meet the optimized printing conditions.

[0157] Specifically, when the above ratio is less than the preset ratio threshold, it means that the printing time of the cavity area is shorter, and the time for printing the current slice as a whole is longer than the time for printing the cavity area. Therefore, within the overall printing time, the liquid in contact with the closed cavity can be fully flowed, and then when printing the cavity area, the liquid remains relatively still. At this time, there is no need to adjust the printing strategy specifically for the closed cavity, and problems that may arise when printing the closed cavity can be avoided.

[0158] This embodiment determines that the cavity image does not meet the optimized printing conditions when the ratio of the closed cavity area to the cross-sectional area of ​​the cavity image is small, and then prints the model slices according to the conventional printing method. This simplifies some printing methods for closed cavities based on the actual structure of the printed part, thereby helping to improve printing efficiency.

[0159] In some optional implementations of this embodiment, as shown in FIG11 , step 20322 includes:

[0160] Step 203221: Determine the cavity degree value of the cavity image based on the cross-sectional geometric information of the cavity image.

[0161] The cross-sectional geometric information may include, but is not limited to, at least one of the following parameters: cavity area, location, shape, and wall thickness. As shown in Figure 12, the area, location, shape, and wall thickness of cavities may be the same or different in different slice layers; and the area, location, shape, and wall thickness of cavities may be the same or different in the same slice layer. Therefore, it is necessary to calculate the cavity degree value of the cavity image based on at least one of the following cross-sectional geometric information: cavity wall thickness, number of cavities, cavity area, cavity shape, and influencing factors between cavities. Based on the cavity degree value, the printing difficulty value can be determined to determine the appropriate printing strategy. Typically, a weight can be assigned to each parameter, and the weighted sum of the parameters can be used to obtain the cavity degree value. The calculation method for the cavity degree value may follow rules such as: the larger the cavity area, the greater the cavity degree value; the smaller the minimum wall thickness of the cavity, the greater the cavity degree value; the closer the cavity is to other cross-sections, the greater the cavity degree value.

[0162] Step 203222: Obtain material parameters of the printing material of the three-dimensional model.

[0163] The material parameters may include but are not limited to at least one of the following: viscosity, hardness, tensile strength, bending strength, etc.

[0164] Step 203223: Determine the cavity printing difficulty value of the cavity image based on the cavity degree value and the material parameters.

[0165] Specifically, different weights can be set for different material parameters, as well as a weight for the cavity degree value. The weighted sum of the material parameters and the cavity degree value is then used to calculate the cavity printing difficulty value. For example, a higher viscosity, lower hardness, lower tensile strength, and lower bending strength of the printing material will result in a higher calculated cavity printing difficulty value.

[0166] This embodiment calculates the cavity printing difficulty value by comprehensively considering material parameters and cavity degree values, thereby obtaining data from more aspects to reflect the magnitude of cavity printing difficulty. By combining the printing material characteristics and structural characteristics, a high-precision printing difficulty value is obtained, which helps to further accurately adjust the printing method according to the printing difficulty value and improve the printing quality of the closed cavity.

[0167] In some optional implementations of this embodiment, step 203221 may be performed as follows:

[0168] The cavity degree value of the cavity image is calculated based on at least one of the cavity wall thickness, the number of cavities, the cavity area, the cavity shape and the influencing factor between cavities included in the cross-sectional geometric information of the cavity image.

[0169] Among them, all the items of the above cross-sectional geometric information can be quantified. By setting the weight of each parameter, the cavity degree value can be calculated. The size of the weight can be set according to the actual printing scenario. The setting principle can follow the following rules:

[0170] The above-mentioned cavity wall thickness includes the minimum wall thickness of each cavity. The smaller the minimum wall thickness, the higher the cavity degree value; the more the above-mentioned cavities, the higher the cavity degree value; the larger the cavity area, the higher the cavity degree value.

[0171] The shape of the cavity can be represented by at least one of the following parameters: the size of the envelope rectangle of each cavity, the size of the minimum circumscribed circle, and the degree of dispersion of the cavity edge. The above parameters representing the shape of the closed cavity can represent the degree of deviation of the cross-sectional shape of the closed cavity from a preset shape (e.g., a circle). For example, the envelope rectangle and the minimum circumscribed circle can be used to describe the similarity between the cross-sectional shape of the closed cavity and the preset shape, respectively. The degree of dispersion can be used to indicate the deviation of a point on the cross-sectional edge of the closed cavity relative to the center point of the cross-sectional area of ​​the closed cavity. Therefore, the degree of dispersion can be used to indicate whether the slice cross section is a regular geometric shape. As shown in Figure 12, the area, position, shape, and wall thickness of the cavities in different slice layers may be the same or different; and the area, position, shape, and wall thickness of the cavities in the same slice layer may be the same or different. Therefore, it is necessary to calculate the cavity degree value of the cavity image based on the cross-sectional geometric information of the cavity image, including at least one of the cavity wall thickness, number of cavities, cavity area, cavity shape, and the influencing factor between cavities. Based on the cavity degree value, the printing difficulty value can be determined to schedule an appropriate printing strategy. Generally, each parameter can be multiplied by the corresponding coefficient and then added to obtain a numerical value representing the degree of deviation from the regular geometric shape. The larger the numerical value, the higher the cavity degree value.

[0172] The influence factors between cavities may include, but are not limited to, at least one of the following: the minimum distance between closed cavities, the relative area ratio between closed cavities, the area ratio of the enveloping rectangle of each closed cavity to the entire slice cross section, the area ratio of the minimum circumscribed circle of each closed cavity to the entire slice cross section, etc. The larger the influence factor, the higher the cavity degree value.

[0173] It should be understood that when the cavity image contains cross-sections of multiple closed cavities, the cavity degree value corresponding to each closed cavity can be calculated separately according to the above parameters and rules, and then the cavity degree value corresponding to the cavity image can be calculated by weighted summation, calculation of average value, etc.

[0174] This embodiment calculates the cavity degree value based on the parameters of multiple dimensions included in the cross-sectional geometric information, so that the calculated cavity degree value can more accurately reflect the difficulty of printing a closed cavity, thereby improving the quality of printing a closed cavity.

[0175] In some optional implementations of this embodiment, based on the embodiment corresponding to FIG. 10 , step 204 may be further performed as follows:

[0176] Based on the correspondence between the preset cavity printing strategy and the cavity printing difficulty value, at least one cavity printing method corresponding to the cavity printing difficulty value of the cavity image is determined as the target cavity printing strategy from at least two cavity printing strategies included in the preset cavity printing strategy.

[0177] Each of the at least two cavity printing strategies can be obtained by setting different printing parameters. For example, the greater the cavity printing difficulty value, the longer the print stays at the minimum distance from the bottom of the tray.

[0178] This embodiment sets multiple cavity printing strategies and selects a target cavity printing strategy corresponding to the calculated cavity printing difficulty value, thereby adaptively adjusting the printing strategy based on the structural characteristics of the current three-dimensional model, so that the current target cavity printing strategy can better match the closed cavity structure of the current model slice, thereby further improving the printing quality of the model.

[0179] In some optional implementation strategies of this embodiment, the at least two cavity printing strategies include at least two of the following:

[0180] Method 1: When the liquid level of the printing material is lower than a preset height, the liquid replenishing device is controlled to replenish the printing material to the material tray so that the liquid level of the printing material remains higher than the rising height of the forming platform.

[0181] The amount of printing material added to the material tray can be set arbitrarily, as long as the liquid level of the printing material is kept higher than the rising height of the forming platform.

[0182] Method 2: When the forming platform descends, when the layer thickness reaches the first preset multiple from the bottom of the material tray, the forming platform is controlled to stop moving. After waiting for the first preset time, the forming platform is controlled to continue descending to the layer thickness reaching the second preset multiple from the bottom of the material tray, and the printing operation is started, wherein the first preset multiple is greater than the second preset multiple.

[0183] Typically, the first preset multiple can be set to any value within the range of 1 times the layer thickness to 10 times the layer thickness, specifically, it can be 1 times, 1.5 times, 2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, 6 times, 6.5 times, 7 times, 7.5 times, 8 times, 8.5 times, 9 times, 9.5 times, 10 times, and interval values ​​between the values. The second preset multiple can be set to 1 times the layer thickness, and the first preset duration can be set to any value within the range of 0.5 seconds to 10 seconds. The time interval can be 0.5 seconds, 1 second, 1.5 seconds, 2 seconds, 2.5 seconds, 3 seconds, 3.5 seconds, 4 seconds, 4.5 seconds, 5 seconds, 5.5 seconds, 6 seconds, 6.5 seconds, 7 seconds, 7.5 seconds, 8 seconds, 8.5 seconds, 9 seconds, 9.5 seconds, 10 seconds, and intervals between the values. That is, the build platform drops to a greater distance from the bottom of the tray to allow the liquid to quickly flow out from the bottom of the print. After waiting for a while, it drops to 1 times the layer thickness, and then prints the slice of this layer according to the normal printing process.

[0184] Method three: when the forming platform descends to a layer thickness that is a third preset multiple from the bottom of the material tray, the forming platform is controlled to stop moving, and after waiting for a second preset time, the forming platform is controlled to rise to a layer thickness that is a second preset multiple from the bottom of the material tray, and the printing operation is started, wherein the third preset multiple is less than the second preset multiple.

[0185] Typically, the third preset multiple can be set to any value within the range of 0.1 times the layer thickness to 0.9 times the layer thickness, specifically, it can be 0.1 times, 0.2 times, 0.3 times, 0.4 times, 0.5 times, 0.6 times, 0.7 times, 0.8 times, 0.9 times, and interval values ​​between each value. The second preset time can be set to a smaller value. For example, it can be set to 0, that is, when it drops to 0.1 times the layer thickness to 0.9 times the layer thickness from the bottom of the material tray, it immediately rises to 1 times the layer thickness from the bottom of the material tray, so that most of the liquid at the bottom of the print flows out to the surrounding area, and then the forming platform is lifted upward to offset the flow of the liquid, and then the layer slice is printed according to the normal printing process.

[0186] Method 4: When the forming platform descends to a layer thickness that is a second preset multiple of the distance from the bottom of the material tray, the forming platform is controlled to stop moving, and the printing operation is started after waiting for a third preset time.

[0187] Typically, the third preset time can be set to any value in the range of 1 second to 20 seconds. That is, when the building platform descends to a distance of 1 times the layer thickness from the bottom of the material tray, it waits for a long time to allow the liquid at the bottom of the print to settle, and then prints the layer slice according to the normal printing process.

[0188] In some optional implementation strategies of this embodiment, the at least two cavity printing strategies include at least two of the following:

[0189] Mode 5: When the build platform descends, when the layer thickness reaches a first preset multiple from the liquid level at the top of the tray, the build platform is controlled to stop moving. After waiting for a first preset time, the build platform is controlled to continue descending until the layer thickness reaches a second preset multiple from the liquid level at the top of the tray, and the printing operation is started. The first preset multiple is less than the second preset multiple.

[0190] Method six: When the forming platform descends to a layer thickness that is a third preset multiple of the liquid level at the top of the material tray, the forming platform is controlled to stop moving. After waiting for a second preset time, the forming platform is controlled to rise to a layer thickness that is a second preset multiple of the liquid level at the top of the material tray, and the printing operation is started, wherein the third preset multiple is greater than the second preset multiple.

[0191] The adjustment method can refer to the second and third methods in the previous embodiment, which will not be described in detail here.

[0192] It should be noted that, of the various printing methods mentioned above, with the exception of Methods 2 and 3, and Methods 5 and 6, which cannot be combined due to conflicts in the control methods of the build platform, the remaining methods can be combined arbitrarily based on the cavity printing difficulty value. For example, when the cavity printing difficulty value is in the lower first range, Method 1 is selected; when it is in the higher second range, Methods 1 and 2 are selected; when it is in the higher third range, Methods 1 and 3 are selected; and when it is in the higher fourth range, Methods 1, 2, and 4 are selected. Top projection technology can be combined based on Methods 1, 4, 5, and 6.

[0193] It should also be noted that the above-mentioned preset duration, preset height, preset multiples and other parameters can be set according to various parameters such as the cavity degree value and material properties in the actual printing scene. The duration, multiples and other parameters listed in this embodiment are merely exemplary and do not constitute the scope of protection limited by the embodiments of the present disclosure.

[0194] The six cavity printing methods provided in this embodiment can flexibly select at least one cavity printing method for printing according to the cavity printing difficulty value when the cavity printing difficulty value is large, further improving the operation accuracy when printing the cavity and thereby improving the printing quality.

[0195] In some optional implementations of this embodiment, step 2032 is further used to:

[0196] If the wall thickness of the closed cavity in the cavity image is greater than or equal to the preset wall thickness, the closed cavity wall in the cavity image is split into a filling area and a contour area, and the filling area and the contour area are printed in sequence.

[0197] As shown in Figure 13A, it shows the original cavity image, Figure 13B shows the split fill area image, and Figure 13C shows the split outline area image. When printing, the fill area can be printed first to prevent the liquid in the cavity from flowing outward, and then the outline area can be printed to modify the surrounding area of ​​the fill area, thereby printing a smooth surface. It should be understood that the fill area image shown in Figure 13B is only an example. In actual printing, the fill area pattern can be set arbitrarily, such as a solid pattern, a grid pattern, a honeycomb pattern, etc.

[0198] It should be noted that the printing method provided in this embodiment can be used alone or in any combination with the four cavity printing methods provided in the above embodiments, thereby further reducing the risk of generating residues when printing closed cavities and further improving the printing quality.

[0199] Figure 14 illustrates a 3D model printing device provided by an embodiment of the present disclosure, which is applied to a 3D printing device including a build platform. The device specifically includes: an acquisition unit 1001 configured to acquire 3D model data; a first determination unit 1002 configured to determine cavity data from the 3D model data; and a printing unit 1003 configured to schedule a corresponding printing strategy based on the cavity data for printing. The printing strategy includes at least one of adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the build platform, adjusting the exposure strategy, and adjusting the image data corresponding to the cavity.

[0200] In some optional implementations of this embodiment, the printing unit includes: a first determination module, configured to determine the cavity part and the non-cavity part of the three-dimensional model based on the cavity data; a scheduling module, configured to schedule the corresponding cavity printing strategy for printing the cavity part, and to schedule the corresponding non-cavity printing strategy for printing the non-cavity part.

[0201] In some optional implementations of this embodiment, the first determination unit includes: a first recognition module, configured to identify the three-dimensional model as a whole to obtain three-dimensional data, wherein the three-dimensional data includes at least one of the following: model three-dimensional position information, model shape, model volume, model wall thickness, and number of sub-models; determining cavity data from the three-dimensional data, wherein the cavity data includes at least one of the following: cavity three-dimensional position information, cavity shape, cavity volume, cavity wall thickness, and number of cavities; and / or, a second recognition module, configured to slice the three-dimensional model and identify the slices where the closed cavities in the three-dimensional model are located as a cavity slice set; identifying each layer of slices in the cavity slice set to obtain cavity data, wherein the cavity data includes: at least one data of the area, position, shape, wall thickness, and number of the slice cross section, and at least one data of the area, position, shape, wall thickness, and number of the cavities in the slice cross section.

[0202] In some optional implementations of this embodiment, the second identification module includes: a generation submodule, configured to generate a two-dimensional slice image of each slice in the slice set to obtain a two-dimensional slice image set; a first determination submodule, configured to determine the cross-sectional geometric information of each two-dimensional slice image in the two-dimensional slice image set; and a second determination submodule, configured to determine the cavity data based on the cross-sectional geometric information.

[0203] In some optional implementations of this embodiment, the printing unit includes: a second determination module, configured to determine, from a set of two-dimensional slice images, a subset of cavity images corresponding to the cavity area based on cross-sectional geometric information; a printing module, configured to determine, for each cavity image in the cavity image subset, whether the cavity image meets the optimized printing conditions based on the cross-sectional geometric information of the cavity image; if the optimized printing conditions are met, determine a target cavity printing strategy corresponding to the cavity image, and print the three-dimensional model slice corresponding to the cavity image based on the target cavity printing strategy.

[0204] In some optional implementations of this embodiment, the second determination module includes: a third determination submodule, configured to determine, for each two-dimensional slice image in the two-dimensional slice image set, the difference between the cavity area in the two-dimensional slice image and the cavity area in the previous two-dimensional slice image based on the cross-sectional geometric information of the two-dimensional slice image; if the difference meets the cavity judgment condition and it is determined that the two-dimensional slice image contains a through hole, determine the size of the through hole; and a fourth determination submodule, configured to determine that the two-dimensional slice image is a cavity image if the size of the through hole is less than or equal to a preset size.

[0205] In some optional implementations of this embodiment, the printing unit includes: a fifth determination submodule, configured to determine the ratio of the closed cavity area to the cross-sectional area of ​​the cavity image based on the cross-sectional geometric information of the cavity image; a sixth determination submodule, configured to determine the cavity printing difficulty value of the cavity image based on the cross-sectional geometric information of the cavity image if the ratio is greater than or equal to a preset ratio threshold; and a seventh determination submodule, configured to determine that the cavity image meets the optimized printing conditions if the cavity printing difficulty value is greater than or equal to the preset difficulty threshold.

[0206] In some optional implementations of this embodiment, the apparatus further includes: a second determining unit configured to determine that the cavity image does not meet the optimized printing condition if the ratio is less than a preset ratio threshold.

[0207] In some optional implementations of this embodiment, the sixth determination submodule is further configured to: determine the cavity degree value of the cavity image based on the cross-sectional geometric information of the cavity image; obtain the material parameters of the printing material of the three-dimensional model; and determine the cavity printing difficulty value of the cavity image based on the cavity degree value and the material parameters.

[0208] In some optional implementations of this embodiment, the sixth determination submodule is further configured to calculate the cavity degree value of the cavity image based on the cross-sectional geometric information of the cavity image, including at least one of the cavity wall thickness, the number of cavities, the cavity area, the cavity shape, and the influencing factor between cavities.

[0209] In some optional implementations of this embodiment, the printing unit is further configured to: based on the correspondence between the preset cavity printing method and the cavity printing difficulty value, determine at least one cavity printing method corresponding to the cavity printing difficulty value of the cavity image as the target cavity printing strategy from at least two cavity printing strategies included in the preset cavity printing strategy.

[0210] In some optional implementations of this embodiment, at least two cavity printing strategies include at least two of the following: Method 1, when the liquid level of the printing material is lower than a preset height, the liquid replenishing device is controlled to replenish the printing material to the material tray so that the liquid level of the printing material remains higher than the rising height of the forming platform; Method 2, when the forming platform descends, when the layer thickness is a first preset multiple from the bottom of the material tray, the forming platform is controlled to stop moving, and after waiting for a first preset time, the forming platform is controlled to continue to descend to a layer thickness of a second preset multiple from the bottom of the material tray, and the printing operation is started, wherein the first preset multiple is greater than the second preset multiple; Method 3, when the forming platform descends to a layer thickness of a third preset multiple from the bottom of the material tray, the forming platform is controlled to stop moving, and after waiting for a second preset time, the forming platform is controlled to rise to a layer thickness of a second preset multiple from the bottom of the material tray, and the printing operation is started, wherein the third preset multiple is less than the second preset multiple; Method 4, when the forming platform descends to a layer thickness of a second preset multiple from the bottom of the material tray, the forming platform is controlled to stop moving, and after waiting for a third preset time, the printing operation is started.

[0211] In some optional implementations of this embodiment, the at least two cavity printing strategies include at least two of the following:

[0212] Mode 5: When the build platform descends, when the layer thickness reaches a first preset multiple from the liquid level at the top of the tray, the build platform is controlled to stop moving. After waiting for a first preset time, the build platform is controlled to continue descending until the layer thickness reaches a second preset multiple from the liquid level at the top of the tray, and the printing operation is started. The first preset multiple is less than the second preset multiple.

[0213] Method six: When the forming platform descends to a layer thickness that is a third preset multiple of the liquid level at the top of the material tray, the forming platform is controlled to stop moving. After waiting for a second preset time, the forming platform is controlled to rise to a layer thickness that is a second preset multiple of the liquid level at the top of the material tray, and the printing operation is started, wherein the third preset multiple is greater than the second preset multiple.

[0214] The adjustment method can refer to the second and third methods in the previous embodiment, which will not be described in detail here.

[0215] In some optional implementations of this embodiment, the printing unit is further configured to: if the wall thickness of the closed cavity in the cavity image is greater than or equal to a preset wall thickness, split the closed cavity wall in the cavity image into a filling area and a contour area, and print the filling area and the contour area in sequence.

[0216] The three-dimensional model printing device provided in this embodiment can be a three-dimensional model printing device as shown in Figure 14, which can execute all steps of the above three-dimensional model printing methods, and thus achieve the technical effects of the above three-dimensional model printing methods. Please refer to the above related description for details. For the sake of brevity, it will not be repeated here.

[0217] FIG15 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present disclosure. The electronic device 1100 shown in FIG15 includes: at least one processor 1101, a memory 1102, at least one network interface 1104, and other user interfaces 1103. The various components in the electronic device 1100 are coupled together via a bus system 1105. It is understood that the bus system 1105 is used to achieve connection and communication between these components. In addition to including a data bus, the bus system 1105 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, various buses are labeled as bus system 1105 in FIG11.

[0218] The user interface 1103 may include a display, a keyboard, or a pointing device (eg, a mouse, a trackball, a touchpad, or a touch screen).

[0219] It is understood that the memory 1102 in the embodiments of the present disclosure may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous DRAM (DDRSDRAM), enhanced synchronous DRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM bus random access memory (DRRAM). The memory 1102 described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0220] In some embodiments, the memory 1102 stores the following elements, executable units, or data structures, or a subset thereof, or an extended set thereof: an operating system 11021 and application programs 11022 .

[0221] The operating system 11021 includes various system programs, such as a framework layer, a core library layer, and a driver layer, for implementing various basic services and handling hardware-based tasks. Application programs 11022 include various application programs, such as a media player and a browser, for implementing various application services. Programs implementing the methods of the embodiments of the present disclosure may be included in application programs 11022.

[0222] In this embodiment, by calling the program or instructions stored in the memory 1102, specifically, the program or instructions stored in the application 11022, the processor 1101 is configured to execute the method steps provided by each method embodiment, for example, including:

[0223] Acquire three-dimensional model data; determine cavity data from the three-dimensional model data; and schedule a corresponding printing strategy based on the cavity data to perform printing, wherein the printing strategy includes at least one of adjusting the liquid level height, controlling the drainage waiting time, controlling the drainage height, controlling the motion parameters of the molding platform, and adjusting the image data corresponding to the cavity.

[0224] The methods disclosed in the above embodiments of the present disclosure can be applied to or implemented by processor 1101. Processor 1101 may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits in processor 1101 or by software instructions. The above processor 1101 may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The methods, steps, and logic block diagrams disclosed in the embodiments of the present disclosure can be implemented or executed. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in conjunction with the embodiments of the present disclosure can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software units in the decoding processor. The software units can be located in a storage medium well-known in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory 1102 , and the processor 1101 reads the information in the memory 1102 and completes the steps of the above method in combination with its hardware.

[0225] It is understood that the embodiments described herein may be implemented using hardware, software, firmware, middleware, microcode, or a combination thereof. For hardware implementation, the processing unit may be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers, microprocessors, or other electronic units or combinations thereof for performing the above-mentioned functions of the present disclosure.

[0226] For software implementation, the techniques described above can be implemented by a unit that performs the functions described above. The software code can be stored in a memory and executed by a processor. The memory can be implemented in the processor or external to the processor.

[0227] The electronic device provided in this embodiment can be an electronic device as shown in Figure 15, which can execute all steps of the three-dimensional model printing methods described above, and thus achieve the technical effects of the three-dimensional model printing methods described above. Please refer to the above related description for details. For the sake of brevity, it will not be repeated here.

[0228] The present disclosure also provides a storage medium (computer-readable storage medium). The storage medium stores one or more programs. The storage medium may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as read-only memory, flash memory, hard disk, or solid-state drive; and the memory may also include a combination of the aforementioned types of memory.

[0229] When one or more programs in the storage medium can be executed by one or more processors, the three-dimensional model printing method executed on the electronic device side can be implemented.

[0230] The processor is configured to execute a program stored in the memory to implement the following steps of a three-dimensional model printing method executed on the electronic device side:

[0231] Acquire three-dimensional model data; determine cavity data from the three-dimensional model data; and schedule a corresponding printing strategy based on the cavity data to perform printing, wherein the printing strategy includes at least one of adjusting the liquid level height, controlling the drainage waiting time, controlling the drainage height, controlling the motion parameters of the molding platform, and adjusting the image data corresponding to the cavity.

[0232] The present disclosure discloses a three-dimensional printing method, which includes: forming at least one base layer on a forming platform of a printing device; according to an adjusted printing strategy, using a light source mechanism of the printing device to project light onto a photosensitive material to solidify the photosensitive material and form a target layer on a construction surface of the printing device, wherein the target layer adheres to the at least one base layer, and the target layer includes an unfilled portion and a filled portion that completely surrounds the unfilled portion, wherein the at least one base layer and the target layer jointly define a cavity; wherein the adjusted printing strategy includes at least one of adjusting a liquid level, controlling a waiting time, controlling a liquid discharge height, controlling forming platform motion parameters, adjusting an exposure strategy, and adjusting image data corresponding to the cavity.

[0233] In some embodiments, adjusting the liquid level includes supplying printing material to a printing device's material tray so that air is not introduced into the cavity region of the model. Figures 16A-16D illustrate a related embodiment in which a build platform 1610 is attached to or carries a cured "inverted cup-shaped" print 1620. Print 1620 includes multiple cured layers, such as the most recently cured layer 1622. Layer 1622 has a thickness of 50 μm, and a liquid level 1632 in a printing device's material tray 1630 is 70 μm high. As shown in Figure 16B, to separate print 1620 (or layer 1622) from the bottom (or film) of the material tray, print 1620 may be moved 130 μm away from the bottom of the material tray 1630. This results in layer 1622 of print 1620 being separated from the liquid material and spaced 60 μm apart from liquid level 1632. As print 1620 moves downward to cure a new layer, there is a risk of air entering the cavity region of print 1620. In FIG16C , the liquid level is raised by supplying material to tray 1630. After print 1620 (or layer 1622) separates from the bottom (or film) of the tray, layer 1622 remains encased in material (in other words, layer 1622 remains below liquid level 1634), and there is essentially no risk of air entering the cavity region of print 1620. In FIG16D , print 1620 moves closer to the bottom of tray 1630 and stops at a distance of 50 μm from the bottom of tray 1630 to solidify layer 1624 having a thickness of 50 μm. During the formation of layers 1622 and 1624, essentially no air enters the cavity region of print 1620.

[0234] In some embodiments, controlling the waiting time includes: controlling the forming platform carrying the at least one base layer to move to a predetermined distance from the construction surface and then to remain stationary for a predetermined time.

[0235] In some embodiments, controlling the drainage height includes controlling the forming platform carrying the at least one base layer to move to a predetermined distance from the building surface.

[0236] In some embodiments, controlling the motion parameters of the building platform includes adjusting at least one of a motion speed and a motion distance of the building platform.

[0237] In some embodiments, adjusting the exposure strategy includes at least one of: performing exposure in separate regions and extending the exposure time. Figures 17A-17B illustrate a related embodiment. To form a target layer associated with the aforementioned cavity, the material may be first solidified to form a portion 1721 of the target layer, and then solidified to form another portion 1722 of the target layer.

[0238] In some embodiments, adjusting the image data corresponding to the cavity includes dividing the slice image and dividing the printing section into multiple parts for sequential printing.

[0239] In some embodiments, at least one base layer includes a cover layer adhered to the target layer, the cover layer covering or masking unfilled portions of the target layer.

[0240] In some embodiments, at least one base layer includes a covering layer and at least one intermediate layer, the at least one intermediate layer is adhered to the target layer and the covering layer, wherein the at least one intermediate layer includes an unfilled portion and a filled portion that completely surrounds the unfilled portion, the covering layer covers or shields the unfilled portion of the at least one intermediate layer, and the unfilled portion of the at least one intermediate layer is connected to the unfilled portion of the target layer.

[0241] In some embodiments, at least one base layer, a target layer on the build surface, and the build surface collectively define a cavity.

[0242] In some embodiments, the construction surface is defined by a film.

[0243] In some embodiments, the parameters of the adjusted printing strategy are determined based on at least one of the following: cavity wall thickness, number of cavities, cavity area, and cavity shape.

[0244] In some embodiments, the adjusted printing strategy includes: lowering the building platform to a predetermined position, where the distance between the predetermined position and the construction surface is greater than or less than the thickness of the target layer; allowing the building platform to stay at the predetermined position for a preset period of time; moving the building platform from the predetermined position to a printing position, where the distance between the printing position and the construction surface is the thickness of the target layer; and causing the light source mechanism to project light to form the target layer.

[0245] In some embodiments, the adjusted printing strategy includes: moving the build platform to a printing position, where the distance between the printing position and the construction surface is the thickness of the target layer; allowing the build platform to stay at the printing position for a preset time; and allowing the light source mechanism to project light to form the target layer.

[0246] In some embodiments, force monitoring is performed during the printing process. For example, a force sensor is mounted on the build platform. As the build platform moves toward the film and contacts the liquid material, an object on the build platform with a forming cup-shaped opening (e.g., an inverted U-shape) also moves toward the film and contacts the liquid material. When the cup-shaped opening is not in contact with the liquid material, it contains air. When the cup-shaped opening contacts the liquid material and continues to move, the air inside is compressed (due to the liquid material occupying a certain space), forcing the liquid material inside the cup-shaped opening to flow outward. This causes the air and liquid material to exert pressure on the build platform, which is detected by the force sensor (e.g., -80N). If the build platform stops moving at this point (i.e., the waiting time starts counting from this point), the liquid material inside the cup-shaped opening gradually flows outward, and the force detected by the force sensor gradually changes and approaches zero. After the waiting time (e.g., 5 seconds), the force detected by the force sensor remains substantially unchanged (e.g., between -10N and 0), indicating that the liquid material inside the cup-shaped opening is essentially not flowing outward. At this point, light can be projected from a light-emitting unit (e.g., a DMD component for DLP) to solidify the liquid material.

[0247] Monitoring the change in force value in the same manner revealed that during the formation of the cup-shaped layer, the waiting time for each layer remained essentially unchanged (e.g., 4.5 to 5.5 seconds). However, after the cup-shaped layer was formed and a new layer without holes was formed, the waiting time was significantly shortened (e.g., 0.5 to 2.0 seconds). For example, when forming a new layer without holes, when the forming platform stopped moving (i.e., the waiting time began counting from this moment), essentially no liquid material flowed outward, and the force detected by the force sensor changed rapidly and approached zero. After the waiting time (e.g., 0.5 seconds), the force detected by the force sensor remained essentially unchanged (e.g., between -10N and 0).

[0248] Monitoring force changes in the same manner revealed that during the formation of the cup-shaped layer, the waiting time for each layer remained essentially constant (e.g., 4.5 to 5.5 seconds). However, after forming many cup-shaped layers (e.g., 200 layers) and then forming a new cup-shaped layer (containing holes), the waiting time was significantly shortened (e.g., 1.5 to 2.5 seconds). For example, when forming a new layer (layer 201) with holes, the build platform stopped moving (i.e., the waiting time began counting from this point), and the air inside the build platform was compressed (because some space was occupied by liquid material), forcing the liquid material inside the cup-shaped layer to flow outward. As can be seen, because the volume of the air cavity is larger and the space occupied by liquid material is less, the degree of air compression is less, and the liquid material inside the cup-shaped layer quickly stops flowing outward. This causes the force detected by the force sensor to change rapidly and approach zero. After the waiting time (e.g., 2.5 seconds), the force detected by the force sensor remains essentially constant (e.g., between -10N and 0).

[0249] By monitoring the force through the force sensor, the waiting time can be adjusted in time to speed up printing efficiency.

[0250] Professionals should also be further aware that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different circuits to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0251] The steps of the circuits or algorithms described in conjunction with the embodiments disclosed herein may be implemented using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0252] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an", and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain", and "have" are inclusive and therefore specify the presence of the stated features, steps, operations, elements, and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The circuit steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0253] The foregoing description is intended only to provide specific embodiments of the present disclosure, intended to enable those skilled in the art to understand and implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not to be limited to the embodiments shown herein, but is to be construed in the broadest manner consistent with the principles and novel features claimed herein. Industrial Applicability

[0254] The solution provided by the embodiments of the present disclosure can be applied to the field of 3D printing technology. In the embodiments of the present disclosure, cavity data is determined from the three-dimensional model data to be printed, and a corresponding printing strategy is scheduled for printing based on the cavity data, wherein the printing strategy includes adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the forming platform, adjusting the exposure strategy, and adjusting at least one of the image data corresponding to the cavity. This allows the user to automatically adjust the printing mode according to the slicing structure of the model without having to change the model structure, adjust the model's placement posture, or modify the printing parameters. This can avoid edge defects in models with printed cavity structures, improve printing quality, and increase printing efficiency.

Claims

1. A three-dimensional model printing method, applied to a 3D printing device, wherein the 3D printing device includes a forming platform, and the method comprises: Obtaining 3D model data; determining cavity data from the three-dimensional model data; According to the cavity data, a corresponding printing strategy is scheduled to perform printing; wherein the printing strategy includes at least one of adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the forming platform, adjusting the exposure strategy, and adjusting the image data corresponding to the cavity.

2. The method according to claim 1, wherein Scheduling a corresponding printing strategy according to the cavity data to perform printing, including: determining a cavity portion and a non-cavity portion of the three-dimensional model based on the cavity data; For the cavity part, a corresponding cavity printing strategy is scheduled for printing, and for the non-cavity part, a corresponding non-cavity printing strategy is scheduled for printing.

3. The method according to claim 1, wherein Determining cavity data from the three-dimensional model data includes: Identify the entire three-dimensional model to obtain three-dimensional data, wherein the three-dimensional data includes at least one of the following: three-dimensional position information of the model, model shape, model volume, model wall thickness, and the number of sub-models; determine the cavity data from the three-dimensional data, wherein the cavity data includes at least one of the following: three-dimensional position information of the cavity, cavity shape, cavity volume, cavity wall thickness, and the number of cavities; and / or, The three-dimensional model is sliced, and the slices where the cavities in the three-dimensional model are located are identified as a cavity slice set; each layer of slices in the cavity slice set is identified to obtain the cavity data, wherein the cavity data includes: at least one data of the area, position, shape, wall thickness, and number of the slice cross section, and at least one data of the area, position, shape, wall thickness, and number of the cavities in the slice cross section.

4. The method according to claim 3, wherein: Identifying each slice in the cavity slice set to obtain the cavity data includes: generating a two-dimensional slice image of each slice in the slice set to obtain a two-dimensional slice image set; determining cross-sectional geometric information of each two-dimensional slice image in the two-dimensional slice image set; The cavity data is determined based on the cross-sectional geometric information.

5. The method according to claim 4, wherein Scheduling a corresponding cavity printing strategy according to the cavity data to perform printing, including: determining, from the set of two-dimensional slice images, a subset of cavity images corresponding to the cavity region based on the cross-sectional geometric information; For each cavity image in the cavity image subset, determine whether the cavity image meets the optimized printing conditions based on the cross-sectional geometric information of the cavity image; if it meets the optimized printing conditions, determine the target cavity printing strategy corresponding to the cavity image, and print the three-dimensional model slice corresponding to the cavity image based on the target cavity printing strategy.

6. The method according to claim 5, wherein: Determining a cavity image subset corresponding to a cavity region from the set of two-dimensional slice images based on the cross-sectional geometric information includes: For each two-dimensional slice image in the set of two-dimensional slice images, determining a difference between a cavity area in the two-dimensional slice image and a cavity area in a previous two-dimensional slice image based on cross-sectional geometric information of the two-dimensional slice image; if the difference meets a cavity determination condition and the two-dimensional slice image is determined to contain a through hole, determining a size of the through hole; If the size of the through hole is smaller than or equal to the preset size, it is determined that the two-dimensional slice image is a cavity image.

7. The method according to claim 5, wherein: Determining whether the cavity image meets the optimized printing conditions based on cross-sectional geometric information of the cavity image includes: determining a ratio of a cavity area to a cross-sectional area of the cavity image based on cross-sectional geometric information of the cavity image; If the ratio is greater than or equal to a preset ratio threshold, determining a cavity printing difficulty value of the cavity image based on cross-sectional geometric information of the cavity image; If the cavity printing difficulty value is greater than or equal to the preset difficulty threshold, it is determined that the cavity image meets the optimized printing conditions.

8. The method according to claim 7, wherein: After determining the ratio of the cavity area to the cross-sectional area of the cavity image based on the cross-sectional geometric information of the cavity image, the method further includes: If the ratio is less than a preset ratio threshold, it is determined that the cavity image does not meet the optimized printing condition.

9. The method according to claim 7, wherein: Determining a cavity printing difficulty value of the cavity image based on cross-sectional geometric information of the cavity image includes: determining a cavity degree value of the cavity image based on cross-sectional geometric information of the cavity image; Obtaining material parameters of a printing material for the three-dimensional model; A cavity printing difficulty value of the cavity image is determined based on the cavity degree value and the material parameter.

10. The method according to claim 9, wherein: Determining a cavity degree value of the cavity image based on cross-sectional geometric information of the cavity image includes: The cavity degree value of the cavity image is calculated based on at least one of the cavity wall thickness, the number of cavities, the cavity area, the cavity shape and the influencing factor between cavities included in the cross-sectional geometric information of the cavity image.

11. The method according to claim 5, wherein: Determining a target cavity printing strategy corresponding to the cavity image includes: Based on the correspondence between the preset cavity printing strategies and the cavity printing difficulty values, at least one cavity printing strategy corresponding to the cavity printing difficulty value of the cavity image is determined as the target cavity printing strategy from at least two cavity printing strategies included in the preset cavity printing strategies.

12. The method according to claim 11, wherein The 3D printing device further includes a material tray, and the at least two cavity printing strategies include at least two of the following: Method 1: When the liquid level of the printing material is lower than a preset height, the liquid replenishing device is controlled to replenish the printing material to the material tray so that the liquid level of the printing material remains higher than the rising height of the forming platform; Mode 2: When the building platform descends, when the layer thickness reaches a first preset multiple from the bottom of the tray, the building platform is controlled to stop moving, and after waiting for a first preset time, the building platform is controlled to continue descending to a layer thickness reaching a second preset multiple from the bottom of the tray, and the printing operation is started, wherein the first preset multiple is greater than the second preset multiple; Mode three, when the forming platform descends to a layer thickness that is a third preset multiple from the bottom of the tray, the forming platform is controlled to stop moving, and after waiting for a second preset time, the forming platform is controlled to rise to a layer thickness that is a second preset multiple from the bottom of the tray, and the printing operation is started, wherein the third preset multiple is less than the second preset multiple; Mode 4: When the forming platform descends to a layer thickness that is a second preset multiple of the thickness from the bottom of the material tray, the forming platform is controlled to stop moving, and the printing operation is started after waiting for a third preset time.

13. The method according to claim 11, wherein The 3D printing device further includes a material tray, and the at least two cavity printing strategies include the following two: Mode 5: When the forming platform descends, when the layer thickness reaches a first preset multiple from the liquid level at the top of the tray, the forming platform is controlled to stop moving, and after waiting for a first preset time, the forming platform is controlled to continue descending to a layer thickness reaching a second preset multiple from the liquid level at the top of the tray, and the printing operation is started, wherein the first preset multiple is less than the second preset multiple; Method six, when the forming platform descends to a layer thickness that is a third preset multiple of the liquid level at the top of the material tray, the forming platform is controlled to stop moving, and after waiting for a second preset time, the forming platform is controlled to rise to a layer thickness that is a second preset multiple of the liquid level at the top of the material tray, and the printing operation is started, wherein the third preset multiple is greater than the second preset multiple.

14. The method according to any one of claims 5 to 13, wherein: Determining a target cavity printing strategy corresponding to the cavity image, and printing a three-dimensional model slice corresponding to the cavity image based on the target cavity printing strategy, including: If the cavity wall thickness in the cavity image is greater than or equal to the preset wall thickness, the cavity wall in the cavity image is divided into a filling area and a contour area, and the filling area and the contour area are printed in sequence.

15. A three-dimensional model printing device, applied to a 3D printing device, wherein the 3D printing device includes a forming platform, and the device comprises: an acquisition unit configured to acquire three-dimensional model data; a first determining unit configured to determine cavity data from the three-dimensional model data; The printing unit is configured to schedule a corresponding printing strategy according to the cavity data for printing; wherein the printing strategy includes at least one of adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the forming platform, adjusting the exposure strategy, and adjusting the image data corresponding to the cavity.

16. An electronic device comprising: memory for storing computer programs; A processor is used to execute the computer program stored in the memory, and when the computer program is executed, the three-dimensional model printing method described in any one of claims 1 to 14 is implemented.

17. A computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the three-dimensional model printing method according to any one of claims 1 to 14 is implemented.

18. A three-dimensional printing method, comprising: forming at least one base layer on a build platform of a printing device; According to the adjusted printing strategy, a light source mechanism of the printing device is used to project light onto the photosensitive material to cure the photosensitive material and form a target layer on a construction surface of the printing device, wherein the target layer adheres to the at least one base layer and includes an unfilled portion and a filled portion completely surrounding the unfilled portion, wherein the at least one base layer and the target layer jointly define a cavity; The adjusted printing strategy includes at least one of adjusting the liquid level, controlling the waiting time, controlling the discharge height, controlling the motion parameters of the molding platform, adjusting the exposure strategy, and adjusting the image data corresponding to the cavity.

19. The three-dimensional printing method according to claim 18, wherein: The adjusting of the liquid level includes supplying printing material to a material tray of the printing device so that air does not enter the cavity area of the model.

20. The three-dimensional printing method according to claim 18, wherein: The controlling of the waiting time includes: controlling the forming platform carrying the at least one base layer to move to a predetermined distance from the construction surface and then to remain stationary for a predetermined time.

21. The three-dimensional printing method according to claim 18, wherein: The controlling of the drainage height includes: controlling the forming platform carrying at least one base layer to move to a predetermined distance from the construction surface.

22. The three-dimensional printing method according to claim 18, wherein: Controlling the motion parameters of the building platform includes adjusting at least one of the motion speed and the motion distance of the building platform.

23. The three-dimensional printing method according to claim 18, wherein: The exposure adjustment strategy includes: at least one of: regional exposure and extended exposure time.

24. The three-dimensional printing method according to claim 18, wherein: The adjusting the image data corresponding to the cavity includes dividing the slice image and dividing the printing section into a plurality of parts for sequential printing.

25. The three-dimensional printing method according to claim 18, wherein: The at least one base layer includes a cover layer adhered to the target layer, the cover layer covering or shielding an unfilled portion of the target layer.

26. The three-dimensional printing method according to claim 18, wherein: The at least one base layer includes a covering layer and at least one intermediate layer, the at least one intermediate layer is adhered to the target layer and the covering layer, wherein the at least one intermediate layer includes an unfilled portion and a filled portion that completely surrounds the unfilled portion, the covering layer covers or shields the unfilled portion of the at least one intermediate layer, and the unfilled portion of the at least one intermediate layer is connected to the unfilled portion of the target layer.

27. The three-dimensional printing method according to claim 18, wherein: The at least one base layer, the target layer on the build surface, and the build surface collectively define a cavity.

28. The three-dimensional printing method according to claim 18, wherein: The construction surface is defined by a membrane.

29. The three-dimensional printing method according to claim 18, wherein: The parameters of the adjusted printing strategy are determined according to at least one of the following items: cavity wall thickness, cavity number, cavity area, and cavity shape.

30. The three-dimensional printing method according to claim 18, wherein: The adjusted printing strategy includes: Lowering the forming platform to a predetermined position, wherein the distance between the predetermined position and the building surface is greater than or less than the thickness of the target layer; Allowing the forming platform to remain at the predetermined position for a predetermined period of time; Moving the building platform from the predetermined position to a printing position, wherein the distance between the printing position and the building surface is the thickness of the target layer; and The light source mechanism is caused to project light to form a target layer.

31. The three-dimensional printing method according to claim 18, wherein: The adjusted printing strategy includes: Moving the build platform to a printing position, wherein the distance between the printing position and the building surface is the thickness of the target layer; Allowing the build platform to remain at the print position for a predetermined period of time; and The light source mechanism is caused to project light to form a target layer.

32. The three-dimensional printing method according to claim 31, wherein: The preset time period is determined based on a change in force detected by a force sensor mounted on the building platform.

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