Three-dimensional model printing method and device

Abstract

The present invention relates to a method and device for printing a three-dimensional model, as well as a tooth model. The three-dimensional model has an inner concave portion formed by an inward depression, and the method includes: forming at least one support portion extending from the inner side wall of the three-dimensional model to the inner concave portion to support the inner concave portion. The three-dimensional printing device is suitable for printing the three-dimensional model. The tooth model includes one or more teeth, at least one of which is a hollow structure and has an inner concave portion formed by an inward depression of a pit and fissure, and the inner concave portion is connected to the inner side wall of the tooth through at least one support portion. The printing method of the present invention only requires a small amount of time and material to form the desired printed three-dimensional model without affecting the surface quality of the model, thereby improving printing efficiency and reducing printing costs, and can also reduce the impact of traditional support fragments on the model surface.

Description

Technical Field

[0001] The present invention relates to three-dimensional printing technology, and in particular to a printing method and equipment for three-dimensional models. Background Art

[0002] In the field of dental medical devices, models of patients' teeth are often required to assist doctors in performing treatment or correction. Since each patient's dental model is unique, it is well-suited for 3D printing. 3D printing technology uses a computer-generated 3D design model as a foundation. Through software layering and discrete processing, and a CNC molding system, laser beams and hot-melt nozzles are used to layer and bond specialized materials such as metal powder, ceramic powder, plastic, and cell tissues, ultimately creating a physical product. Unlike traditional manufacturing, which uses molds, turning, and milling to shape and cut raw materials to produce finished products, 3D printing transforms a 3D solid into several 2D surfaces. Production is achieved through material processing and layer-by-layer stacking, significantly reducing manufacturing complexity. This digital manufacturing model eliminates the need for complex processes, large machine tools, or extensive human resources. It can generate complex parts of various shapes directly from computer graphics data, making manufacturing accessible to a wider range of people.

[0003] The molding methods used in 3D printing technology are still evolving, and the materials used are also diverse. Among these molding methods, stereolithography (SLA) is the most mature. SLA utilizes the principle that UV-curable materials solidify upon exposure to ultraviolet light, allowing for additive molding. This method offers high molding precision, excellent surface finish, and high material utilization.

[0004] The photocuring method prints layer by layer from the bottom (or top) to form a workpiece. During this process, since the molded object exists in a liquid photocurable resin, in order to ensure that the molded object does not drift, each layer of material needs to be supported by the structure below it and connected to the molding base. Therefore, the 3D printed digital model will contain some redundant support structures to provide support for the parts of the original model that are connected to the upper structure but suspended from the lower structure. Taking the tooth model as an example, each tooth in the model is a hollow structure, and the pits and fissures of the teeth are concave inward to form a concave part inside the tooth. When printing the teeth layer by layer from the root, additional support columns are formed under the concave part to support the concave part. This method increases the time and material consumed in printing, and the support fragments may stick to the surface of the model, affecting the quality of the product. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method and device for printing a three-dimensional model, which does not require the formation of support columns extending from the bottom to the inner recess.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is a method for printing a three-dimensional model, wherein the three-dimensional model has an inner concave portion formed by being recessed inward, and the method includes: forming at least one support portion extending from the inner side wall of the three-dimensional model to the inner concave portion to support the inner concave portion.

[0007] Optionally, before forming the inner recess, at least one supporting portion is formed, wherein the at least one supporting portion extends obliquely upward from the inner side wall of the three-dimensional model to a predetermined forming position of the inner recess.

[0008] Optionally, when forming the inner recess, at least one support portion is formed, extending horizontally from the inner side wall of the three-dimensional model to the inner recess.

[0009] Optionally, the inner concave portion and the support portion are printed layer by layer from the bottom end of the three-dimensional model.

[0010] Optionally, the three-dimensional model is printed using a stereolithography three-dimensional printing method.

[0011] Optionally, when forming the inner recess, two support portions located on the same straight line are formed.

[0012] Optionally, when forming the inner recess, at least three support portions are formed that are connected to the inner side wall of the three-dimensional model from different horizontal directions.

[0013] Optionally, the support portion is sheet-shaped and parallel to the height direction of the three-dimensional model.

[0014] Optionally, when printing the inner concave portion and the support portion, each layer of the support portion is linear.

[0015] Optionally, the three-dimensional model is a tooth model, which includes one or more teeth, wherein at least one tooth has pits and fissures and is a hollow structure, wherein the inner recess is formed by the inward depression of the pits and fissures of the at least one tooth.

[0016] Optionally, the method further comprises retaining the support portion when using the three-dimensional model.

[0017] Optionally, before forming at least one supporting portion extending from the inner wall of the three-dimensional model to the inner recess to support the inner recess, the method further includes: dividing the digital three-dimensional model into multiple layers; identifying an island-type area that is not connected to the main body in each layer of the multiple layers, the island-type area being one of the layers of the inner recess; wherein when an island-type area is identified as existing in a layer of the digital three-dimensional model, forming a layer of the at least one supporting portion several layers in advance.

[0018] Optionally, before forming at least one support portion extending from the inner side wall of the three-dimensional model to the recessed portion to support the recessed portion, the method further includes: dividing the digital three-dimensional model into multiple layers; identifying an island-type area that is not connected to the main body in each layer of the multiple layers, wherein the island-type area is one of the layers of the recessed portion; wherein when an island-type area is identified as existing in a layer of the digital three-dimensional model, a layer of the at least one support portion is formed.

[0019] The technical solution adopted by the present invention to solve the above-mentioned technical problems also proposes a three-dimensional printing device suitable for printing a three-dimensional model, wherein the three-dimensional model has an inwardly recessed portion. The three-dimensional printing device includes a printing mechanism and a controller, and the controller is configured to control the printing mechanism to execute the above-mentioned method.

[0020] The technical solution adopted by the present invention to solve the above-mentioned technical problems also proposes a tooth model, comprising one or more teeth, wherein at least one tooth has pits and grooves and is a hollow structure, and the at least one tooth has an inner recess formed by the inward depression of the pits and grooves, characterized in that the inner recess is connected to the inner wall of the tooth through at least one supporting portion.

[0021] Optionally, the at least one supporting portion extends obliquely upward from the inner side wall of the tooth to the inner recess.

[0022] Optionally, the at least one supporting portion extends horizontally from the inner side wall of the tooth to the inner recess.

[0023] Optionally, there are two supporting parts and they are located on the same straight line.

[0024] Optionally, the number of the supporting parts is more than two and they are connected to the inner wall of the tooth from different horizontal directions.

[0025] Optionally, the supporting portion is sheet-shaped and parallel to the height direction of the tooth.

[0026] The technical solution adopted by the present invention to solve the above-mentioned technical problems also proposes a method for providing a digital tooth model, including providing a digital tooth model, wherein the digital tooth model includes one or more teeth, wherein at least one tooth has an inner recess formed by an inward depression of the pit and fissure, wherein the inner recess is connected to the inner wall of the tooth through at least one supporting portion.

[0027] When forming the inner concave portion of the 3D model, the 3D printing method and apparatus of the present invention form at least one support portion extending from the inner sidewall of the 3D model toward the inner concave portion to support the inner concave portion. This eliminates the need for forming vertical support columns beneath the inner concave portion, thereby saving time and material for printing the support columns. In one aspect of the present invention, the support portion is sheet-shaped and can be formed in a minimal amount of time and material, thereby improving printing efficiency and reducing printing costs. Furthermore, the support component is not removed after printing, preventing support debris from affecting the model surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, in which:

[0029] Figure 1 The basic structure of a light-curing 3D printing device according to an embodiment of the present invention is shown.

[0030] Figure 2 This is a diagram of a normal tooth structure.

[0031] Figure 3 It is a three-dimensional image of a tooth model.

[0032] Figure 4A 、 4B yes Figure 3 A schematic diagram of a conventional internal structure of a tooth in the tooth model shown.

[0033] Figure 5A Schematic diagram of an exemplary internal structure of a tooth in the tooth model according to the first embodiment of the present invention.

[0034] Figure 5B Schematic diagram of an exemplary internal structure of a tooth in a tooth model according to the second embodiment of the present invention.

[0035] Figure 6A yes Figure 5A A variation of the illustrated embodiment.

[0036] Figure 6B yes Figure 5B A variation of the illustrated embodiment.

[0037] Figure 7A Schematic diagram of an exemplary internal structure of a tooth in a tooth model according to the third embodiment of the present invention.

[0038] Figure 7B Schematic diagram of an exemplary internal structure of a tooth in a tooth model according to a fourth embodiment of the present invention.

[0039] Figure 8A Schematic diagram of an exemplary internal structure of a tooth in a tooth model according to a fifth embodiment of the present invention.

[0040] Figure 8B yes Figure 8A A variation of the illustrated embodiment.

[0041] Figure 9 A flow chart of a photo-curing 3D printing method according to an embodiment of the present invention is shown.

[0042] Figures 10A-10D A schematic diagram of a light-curing 3D printing process according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0044] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0045] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," and / or "the" do not refer to the singular and may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0046] It should be understood that when a component is referred to as being “on another component,” “connected to another component,” “coupled to another component,” or “contacting another component,” it can be directly on, connected to, coupled to, or contacting the other component, or intervening components may be present. In contrast, when a component is referred to as being “directly on another component,” “directly connected to,” “directly coupled to,” or “directly contacting” another component, there are no intervening components. Similarly, when a first component is referred to as being “electrically in contact with” or “electrically coupled to” a second component, an electrical path exists between the first and second components that allows current to flow. This electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between the conductive components.

[0047] Figure 1The basic structure of a three-dimensional (3D) photocuring printing device according to an embodiment of the present invention is shown. This 3D printing device 100 includes a material tank 110 for accommodating photocurable resin, an image exposure system 120 for curing the photocurable resin, and a lifting platform 130 for connecting the molded workpiece. The image exposure system 120 is located above the material tank 110 and can irradiate a light beam image to cure a layer of photocurable resin on the liquid surface of the material tank 110. Each time the image exposure system 120 irradiates a light beam image to cure a layer of photocurable resin, the lifting platform 130 will drive the molded layer of photocurable resin to descend slightly, and use the scraper 131 to evenly spread the photocurable resin on the top surface of the cured workpiece, waiting for the next irradiation. In this cycle, a three-dimensional workpiece formed layer by layer will be obtained.

[0048] The image exposure system 120 can irradiate a light beam image onto the photocurable resin to form a desired exposure pattern. The image exposure system 120 can use various known technologies capable of forming a light beam image.

[0049] For example, in one embodiment, the image exposure system 120 may utilize Digital Light Processing (DLP) projection technology. DLP projection imaging technology utilizes a digital micromirror device (DMD) to control the reflection of light. A DMD can be considered a mirror. This mirror is composed of hundreds of thousands or even millions of micromirrors. Each micromirror represents a pixel, and the image is composed of these pixels.

[0050] In another embodiment, the image exposure system 120 may also utilize liquid crystal (LCD) projection technology. An LCD panel contains numerous pixels, each of which can independently control the polarization direction of polarized light. Polarization filters on both sides of the LCD panel can control whether light from a particular pixel passes through. Therefore, the light beam passing through the LCD panel system is imaged.

[0051] In yet another embodiment, laser printing technology may also be used.

[0052] The stereolithography 3D printing device 100 takes as input a 3D data model of the object being printed and decomposes it into multiple 2D images. Each 2D image represents a layer of the object being printed. The stereolithography 3D printing device 100 transmits these 2D images to the image exposure system 120, which then projects them.

[0053] In an embodiment of the present invention, the Figure 1The photocurable 3D printing device 100 shown in the figure is used to print a 3D model. For a 3D model with a cavity structure, when the outer surface corresponding to the cavity structure has an inward depression, an inner concave portion will also be formed. When 3D printing such a cavity structure with an inner concave portion, additional support structures are required, which is both time-consuming and material-intensive. The embodiments of the present invention use a tooth model as an example to specifically illustrate the 3D model printing method of the present invention.

[0054] Figure 2 This is a diagram of a normal tooth structure. Figure 2 As shown, a healthy tooth mainly consists of a crown 210 exposed outside the gum and a root 220 covered by the gum. The structure of a tooth from the outside to the inside is enamel 230, dentin 240 and cementum 250. In the center of the tooth is a cavity called the pulp cavity 260, which contains the dental pulp. Figure 2 The figure shows a molar with a downward concave portion on the top of its crown 210. The three-dimensional printing method and apparatus of the tooth model of the present invention are mainly for the tooth crown 210 with a downward concave portion on the top, and to save material, the tooth model is designed as a shell structure with uniform thickness.

[0055] Figure 3 This is a three-dimensional image of a common tooth model. A tooth model mainly includes upper teeth, lower teeth and gums. Figure 3 The dental model shown only includes the lower teeth and gums. A healthy adult typically has 32 teeth. Teeth are categorized by form and function as incisors, canines, bicuspids (premolars), and molars. The crowns of bicuspids and molars have a slight downward depression.

[0056] Figure 4A 、 4B yes Figure 3 Schematic diagram of the internal structure of the tooth in the tooth model shown. Figure 4A As shown, the tooth model is a hollow structure with a downwardly concave portion 500 on the outer surface of the crown. Since the tooth model is designed as a shell structure with uniform thickness, an inner recess 510 is also formed inside the tooth. This inner recess 510 protrudes downward within the hollow structure inside the tooth, and the point on the inner recess 510 closest to the bottom of the tooth model is its vertex M. Correspondingly, the cavity inside the tooth also has a plurality of upwardly protruding tops 512. There are two or more tops 512. The distance between each top 512 and the bottom of the tooth model can be different. The distance between each top 512 and the bottom of the tooth model is greater than the distance between the inner recess 510 and the bottom of the tooth model.

[0057] When the tooth model is 3D printed, it is usually printed layer by layer from the root of the tooth. In order to support the inner concave portion 510 of the tooth model, a support column 400 needs to be printed layer by layer starting from the bottom layer corresponding to the position of the inner concave portion until the support column 400 reaches the position of the vertex M of the inner concave portion 510. Figure 4B As shown. Furthermore, the support column 400 can continue to wrap upward around other parts of the inner recess 510 to enhance support. However, this method is not only time-consuming and material-intensive, but also requires the user to remove the support column after the dental model is completed, as it adds an extra support column to the hollow structure.

[0058] Example 1

[0059] Figure 5A Schematic diagram of the internal structure of the tooth in the tooth mold of the first embodiment of the present invention. Figure 5A As shown, the inner concave portion 510 of the model is supported by a support portion 521. One end of the support portion 521 is connected to the inner side wall 520 of the model, and the other end of the support portion 521 is connected to the inner concave portion 510. The portion where the support portion 521 is connected to the inner side wall 520 of the model can be Figure 5A Any position between position A and position B in the mold. Position A is a position on the inner wall 520 at the same level as the inner recess 510, and position B is located at the bottom of the inner wall 520 of the mold. When the position where the support portion 521 is connected to the inner wall 520 of the mold is below position A, the support portion 521 is connected obliquely between the inner wall 520 and the inner recess 510.

[0060] Example 2

[0061] Figure 5B Schematic diagram of the internal structure of the tooth in the tooth model of the second embodiment of the present invention. Figure 5B As shown, when the portion where the support portion 521 is connected to the inner wall 520 of the model is at position A, that is, the support portion 521 is horizontally connected between the inner wall 520 and the inner recess 510 .

[0062] exist Figure 5A and 5B In the illustrated embodiment, the support portion 521 may be in a columnar or linear shape.

[0063] In other embodiments, the tooth model may include two or more supporting parts 521 . Figures 6A-6B 、 Figures 7A-7B The illustrated embodiments all include two or more support portions 521 .

[0064] Figure 6A Shown Figure 5A A variation of the embodiment shown. Figure 6A As shown, it is Figure 5A Based on the tooth model shown in FIG, in addition to a support portion 521 obliquely connected between the inner concave portion 510 and the inner side wall 520 of the tooth model, several auxiliary support portions 522 are added. Figure 5A The original support parts 521 of the tooth model of the illustrated embodiment are not in complete contact with each other, and each auxiliary support part 522 is also not in complete contact with each other. That is to say, the auxiliary support part 522 closest to the original support part 521 can be in contact with the original support part 521 at one end, but not in contact with the other end; two adjacent auxiliary support parts 522 can also be in contact with each other at one end, but not in contact with the other end. Preferably, in this variation, the direction of each newly added auxiliary support part 522 is parallel to the direction of the original support part 521, and there is a certain distance between each other. That is to say, all the auxiliary support parts 522 and the original support part 521 are not in contact with each other, such as Figure 6A As shown, the support parts are generally in the shape of parallel ladders.

[0065] Figure 6B Shown Figure 5B A variation of the embodiment shown. Figure 6A The variation shown is similar to that shown in Figure 6B The variation shown is in Figure 5B Based on the tooth model shown in FIG, in addition to a support portion 521 horizontally connected between the inner concave portion 510 and the inner side wall 520 of the tooth model, several auxiliary support portions 522 are added. Figure 5B The original support parts 521 of the tooth model of the illustrated embodiment are not in complete contact with each other, and each auxiliary support part 522 is also not in complete contact with each other. That is to say, the auxiliary support part 522 closest to the original support part 521 can be in contact with the original support part 521 at one end, but not in contact with the other end; two adjacent auxiliary support parts 522 can also be in contact with each other at one end, but not in contact with the other end. Preferably, in this variation, the direction of each newly added auxiliary support part 522 is parallel to the direction of the original support part 521, and there is a certain distance between each other. That is to say, all the auxiliary support parts 522 and the original support part 521 are not in contact with each other, such as Figure 6B As shown, the supporting parts are generally in the shape of parallel ladders.

[0066] It is understandable that Figure 6A and Figure 6B The embodiment shown is compared to Figure 5A and 5BIn the embodiment shown, two or more supporting portions 521 can provide better support for the inner recess 510 in the tooth model.

[0067] Example 3 and Example 4

[0068] Figure 7A Schematic diagram of an exemplary internal structure of a tooth in a tooth model according to the third embodiment of the present invention. Figure 7B Schematic diagram of the internal structure of the tooth in the tooth model of the fourth embodiment of the present invention. Figure 7A As shown, a plurality of support portions 521 are connected obliquely between the inner side wall 520 and the inner recess 510. Figure 7B As shown, a plurality of support portions 521 are horizontally connected between the inner sidewall 520 and the inner recess 510 .

[0069] It is understandable that the multiple support portions 521 can be evenly or unevenly distributed in the cavity of the tooth model, with the vertex M of the inner recess 510 as the center.

[0070] Preferably, when the tooth model has two supporting parts 521, and the two supporting parts 521 are horizontally connected between the inner side wall 520 and the inner recess 510, the two supporting parts 521 are located on the same straight line. Figure 7B The advantageous effect of this preferred embodiment is that the process and algorithm are relatively simple.

[0071] In other embodiments, the plurality of support portions 521 may include both obliquely connected support portions 521 and horizontally connected support portions 521 .

[0072] It is understood that the use of multiple support portions 521 can provide better support for the inner concave portion 510 of the tooth model. In particular, using three support portions 521 connected obliquely or horizontally and evenly distributed on the circumference of the circle with the vertex M of the inner concave portion 510 as the center has a better support effect.

[0073] Example 5

[0074] Figure 8A Schematic diagram of the internal structure of the tooth in the tooth model of the fifth embodiment of the present invention. Figure 8AAs shown, the support portion 521 is sheet-shaped and parallel to the height direction of the tooth model. The portion where the support portion 521 is continuously connected to the inner side wall 520 of the tooth model is from position C to position D, and the portion where the support portion 521 is continuously connected to the inner recess 510 is from position M to position N. Among them, position C is not lower than position B at the bottom of the tooth model and not higher than position A; position D is higher than position A; position M is the vertex on the inner recess 510 closest to the bottom of the tooth model; position N is a position on the inner recess 510 that is higher than position M. It can be understood that when position M coincides with position N, and position D coincides with position C, this embodiment is equivalent to Figure 5A Or the embodiment shown in 5B.

[0075] Figure 8B yes Figure 8A A variation of the embodiment shown. Figure 8B As shown, the sheet-shaped support portion 521 has a corresponding top portion 512 at a corresponding position in the cavity of the tooth model, and the sheet-shaped support portion 521 can be in contact with the top portion 512 at its highest. Figure 8B As shown, position N and position D both coincide with the top 512 .

[0076] In other embodiments, there may be more than two sheet-shaped support portions 521 in the tooth model, which are evenly or unevenly distributed in the cavity of the tooth model with the vertex M of the inner concave portion 510 as the center.

[0077] It should be noted that in the above embodiment of the tooth model, no matter the shape of the support portion 521 is columnar, linear or sheet-like, it needs to have sufficient thickness to provide sufficient support strength. For example, the thickness is greater than 0.3 mm.

[0078] The present invention also includes a method for providing a digital tooth model. The digital tooth model provided by the method includes one or more teeth, wherein at least one tooth (e.g., a molar) is a hollow structure and has an inner concave portion 510 formed by an inward depression of a pit and fissure. The inner concave portion 510 is connected to the inner side wall 520 of the tooth model by at least one support portion 521. The structure of the support portion 521 includes the structure of the aforementioned reference Figures 5A-8B The digital tooth model can be stored in a server and can be downloaded to Figure 1 The 3D printing device shown is used for printing.

[0079] Figure 9 FIG. 1 is a flow chart showing a method for photo-curing 3D printing according to an embodiment of the present invention. Figure 9 As shown, the steps of the printing method include:

[0080] Step 901: Obtain a three-dimensional data model of the printing object. For example, obtain a digital tooth model from a server. In one embodiment, this digital tooth model can be Figures 5A-8B In another embodiment, the digital tooth model may be Figure 4A The following steps will be based on the digital tooth model. Figure 4A The structure shown is used as an example.

[0081] Step 902: Divide the three-dimensional data model into multiple layers.

[0082] This step can be implemented in the controller of the three-dimensional printing device 100. This step is a conventional step in three-dimensional printing and will not be expanded here.

[0083] Step 903: Identify isolated island regions in each layer that are not connected to the main body.

[0084] This step can be implemented in the controller of the 3D printing device 100. During this step, the controller uses an image processing algorithm to identify isolated island regions within a layer of the 3D data model. These island regions are not connected to the main body and therefore cannot be supported independently, requiring additional support. Therefore, corresponding support structures must be printed during subsequent printing.

[0085] Step 904: Print each layer one by one.

[0086] This step can be implemented by the controller of the 3D printing device 100 controlling the printing mechanism including the image exposure system 120 and the lifting platform 130. In this printing process, in addition to printing according to the digital tooth model, corresponding support parts are also added according to the recognition result of step 903.

[0087] Specifically, for the inclined support part, when an island-type area is identified in a layer of the digital tooth model, a layer of the support part is formed several layers ahead of the island-type area. Furthermore, the layers of the support part are continuously formed until they are connected to the island-type area. Figure 5A For the structure, it is only necessary to form a support layer of several layers of island-type areas in advance when the first layer of island-type areas is identified. Figure 6A and Figure 8A 、 8B In terms of the structure, when the Nth (N is greater than or equal to 2) layer of island-type regions is identified, several layers of island-type regions can be advanced to form a layer of the support portion.

[0088] For the horizontal support portion, when an island-type region is identified in a layer of the digital tooth model, a layer of support portion is formed that is located in the same layer as the island-type region. Figure 5B For the structure, it is only necessary to form a layer of support portion on the same layer of the island-shaped area when the first layer of the island-shaped area is identified. Figure 6B In terms of the structure, when the Nth (N is greater than or equal to 2) layer of island-type regions is identified, a layer of support portion can be formed on the same layer of the island-type regions.

[0089] It should be noted that step 903 and step 904 can be partially executed in parallel, for example, the process of identifying the island-type area is simultaneously printing in step 904. Alternatively, step 903 and step 904 can also be executed sequentially, for example, identifying the island-type area first, and then executing step 904.

[0090] Figures 10A-10D A schematic diagram of a light-curing 3D printing process according to an embodiment of the present invention is shown. Taking a tooth model as an example, Figure 9 The printing method shown in FIG. 9 is further described in step 904. In this printing process, the tooth model is printed layer by layer starting from the bottom to the top. Figure 10A As shown, Figure 8B Taking the internal structure of the tooth model shown in the figure as an example, when printing starts, the 3D printer first prints the bottom of the tooth model (a tooth in the tooth model is shown in the figure). The position of the printed layer is as follows Figure 10A As shown by the dotted line on the left, the horizontal cross-section of the tooth model corresponding to the position of the dotted line is as follows Figure 10A The image on the right shows an irregular shape. Since the walls between adjacent teeth in the tooth model do not need to be printed, the bottom of a single tooth is not a closed structure.

[0091] During the layer-by-layer printing process, since the digital model of the tooth model to be printed has been stored in advance in the printing device, the processor of the printing device can know in advance the location of the inner concave portion 510 in the hollow structure of the tooth model by executing step 903. According to the user's settings or the default settings of the printing device itself, the printing device can start to form at least one support portion 521 before printing the layer where the inner concave portion 510 is located. Figure 10B As shown in FIG. 1 , in this embodiment, the sheet-like support portion 521 is connected between the inner side wall 520 of the tooth model and the inner recess 510. Therefore, before the layer-by-layer printing reaches the layer where the inner recess 510 is located, the printing device will start printing the support portion 521 in advance. The position of the printed layer is shown in FIG. Figure 10B As shown by the dotted line on the left figure, this layer indicates that a small part of the support portion 521 near the bottom of the tooth model is connected to the inner wall 520 of the tooth model. The horizontal cross-section of the tooth model corresponding to the position of the dotted line is shown in FIG. Figure 10BAs shown in the right figure, on the tooth model, there is a small linear or columnar protrusion 521a connected to the inner wall 520 of the tooth model. The protrusion 521a is a part of the sheet-shaped supporting portion 521.

[0092] Figure 10C Schematic diagram of the printing process when the sheet-shaped support portion 521 is in the middle. Figure 10C As shown by the dotted line on the left, this layer indicates that about half of the structure of the support portion 521 is connected to the inner wall 520 of the tooth model. The horizontal cross-section of the tooth model corresponding to the position of the dotted line is shown in FIG. Figure 10C As shown in the right figure, on the tooth model, there is a linear or columnar support portion 521b connected to the inner wall 520 of the tooth model.

[0093] Figure 10D Schematic diagram when printing reaches the top M of the concave portion 510. The position of the printed layer is as follows: Figure 10D As shown by the dotted line on the left, the layer indicates that the sheet-like support portion 521 has connected the inner wall 520 of the tooth model with the inner concave portion 510. The horizontal cross-sectional view of the tooth model corresponding to the position of the dotted line is shown in FIG. Figure 10D As shown in the right figure, on the tooth model, there is a linear or columnar support portion 521 c between the top M of the inner recess 510 and the inner side wall 520 of the tooth model.

[0094] It is understandable that the above Figures 10A-10D The description of layer-by-layer printing is based on Figure 8B The embodiment shown is taken as an example. Figures 5A-8A The printing process of the illustrated embodiment is also applicable to the above-mentioned printing process.

[0095] The basic concepts have been described above. It will be apparent to those skilled in the art that the above disclosures are merely illustrative and do not constitute limitations on this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to this application. Such modifications, improvements, and amendments are suggested in this application and remain within the spirit and scope of the exemplary embodiments of this application.

[0096] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0097] Some aspects of the methods and systems of the present application can be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software can all be referred to as "data blocks", "modules", "engines", "units", "components" or "systems". The processor can be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors or combinations thereof. In addition, various aspects of the present application may be expressed as computer products located in one or more computer-readable media, which include computer-readable program code. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, tapes...), optical disks (e.g., compact disks (CDs), digital versatile disks (DVDs)...), smart cards, and flash memory devices (e.g., cards, sticks, key drives...).

[0098] A computer-readable signal medium may include a propagated data signal containing computer program code, for example, in baseband or as part of a carrier wave. The propagated signal may have a variety of manifestations, including electromagnetic, optical, etc., or a suitable combination thereof. A computer-readable signal medium may be any computer-readable medium other than a computer-readable storage medium that can be connected to an instruction execution system, device, or apparatus to communicate, propagate, or transmit a program for use. The program code on the computer-readable signal medium may be propagated via any suitable medium, including radio, cable, fiber optic cable, radio frequency signal, or similar medium, or any combination of the above.

[0099] In addition, unless expressly stated in the claims, the order of the processing elements and sequences described in this application, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of this application. Although the above disclosure discusses some of the invention embodiments currently considered useful through various examples, it should be understood that such details are only for illustrative purposes, and the attached claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this application. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

[0100] Similarly, it should be noted that, in order to simplify the presentation of this application and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this application sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single embodiment disclosed above.

[0101] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values are as accurate as possible within the feasible range.

[0102] Although the present invention has been described with reference to the current specific embodiments, those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention, and that various equivalent changes or substitutions may be made without departing from the spirit of the present invention. Therefore, any changes or modifications to the above embodiments within the spirit of the present invention shall fall within the scope of the claims of this application.

Claims

1. A method for printing a three-dimensional model, wherein the three-dimensional model has an inwardly recessed portion, the method comprising: At least one supporting portion is formed extending from the inner side wall of the three-dimensional model to the inner concave portion to support the inner concave portion; wherein, The three-dimensional model is a tooth model, which includes one or more teeth, wherein at least one tooth has a pit and a groove and is a hollow structure, wherein the inner concave portion is formed by the inward depression of the pit and the groove of the at least one tooth.

2. The method according to claim 1, wherein Before forming the inner concave portion, at least one supporting portion is formed, wherein the at least one supporting portion extends obliquely upward from the inner side wall of the three-dimensional model to a predetermined forming position of the inner concave portion.

3. The method according to claim 1, wherein When forming the inner recess, at least one support portion is formed, extending horizontally from the inner side wall of the three-dimensional model to the inner recess.

4. The method according to any one of claims 1 to 3, wherein The inner concave portion and the support portion are printed layer by layer from the bottom end of the three-dimensional model.

5. The method according to claim 1, wherein The three-dimensional model is printed using a photo-stereolithography three-dimensional printing method.

6. The method according to claim 1, wherein When the inner concave portion is formed, two support portions located on the same straight line are formed.

7. The method according to claim 1, wherein When the inner recess is formed, at least three support portions connected to the inner side wall of the three-dimensional model from different horizontal directions are formed.

8. The method according to claim 1, wherein The supporting portion is sheet-shaped and parallel to the height direction of the three-dimensional model.

9. The method according to claim 4, wherein When printing the inner concave portion and the support portion, each layer of the support portion is in a linear shape.

10. The method according to claim 1, wherein Also included is retaining the support portion while using the three-dimensional model.

11. The method according to claim 2, wherein Before forming at least one supporting portion extending from the inner side wall of the three-dimensional model to the inner concave portion to support the inner concave portion, the method further includes: Dividing the digital three-dimensional model into multiple layers; Identifying an island-type region in each layer of the plurality of layers that is not connected to the main body, wherein the island-type region is one of the layers of the inner concave portion; When it is identified that an island-type region exists in a layer of the digital three-dimensional model, a layer of the at least one support portion is formed several layers in advance.

12. The method according to claim 3, wherein Before forming at least one supporting portion extending from the inner side wall of the three-dimensional model to the inner concave portion to support the inner concave portion, the method further includes: Dividing the digital three-dimensional model into multiple layers; Identifying an island-type region in each layer of the plurality of layers that is not connected to the main body, wherein the island-type region is one of the layers of the inner concave portion; When an island-type area is identified in a layer of the digital three-dimensional model, a layer of the at least one support portion is formed.

13. A three-dimensional printing device, suitable for printing a three-dimensional model, wherein the three-dimensional model has an inwardly recessed portion, the three-dimensional printing device comprising a printing mechanism and a controller, wherein the controller is configured to control the printing mechanism to execute the method according to any one of claims 1 to 12.

14. A tooth model comprising one or more teeth, wherein at least one tooth has a pit and a groove and is a hollow structure, and the at least one tooth has an inner concave portion formed by the pit and the groove being sunken inward, characterized in that: The inner recess is connected to the inner wall of the tooth via at least one supporting portion, and the tooth model is generated by the method according to any one of claims 1 to 12.

15. The tooth model according to claim 14, wherein The at least one supporting portion extends obliquely upward from the inner side wall of the tooth to the inner recess.

16. The tooth model according to claim 14, wherein The at least one supporting portion extends horizontally from the inner side wall of the tooth to the inner recess.

17. The tooth model according to claim 14, wherein There are two supporting parts and they are located on the same straight line.

18. The tooth model according to claim 14, wherein The number of the supporting parts is more than two and the supporting parts are connected to the inner side wall of the tooth from different horizontal directions.

19. The tooth model according to claim 14, wherein The supporting portion is sheet-shaped and parallel to the height direction of the teeth.

20. A method for providing a digital tooth model, comprising providing a digital tooth model, wherein the digital tooth model includes one or more teeth, wherein at least one tooth has an inner recess formed by an inward depression of a pit or fissure, wherein the inner recess is connected to an inner side wall of the tooth via at least one support portion, and the digital tooth model is used in the method according to any one of claims 1 to 12.

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