Photocurable three-dimensional printing method, system, apparatus, and computer readable medium

Abstract

The application provides a light-curing three-dimensional printing method, system, device and computer readable medium. The light-curing three-dimensional printing method comprises: obtaining a three-dimensional data model of a printing object; dividing the three-dimensional data model into multiple layers; and performing shrinkage processing on the edges in at least one horizontal direction of a preset number of bottom layers of the three-dimensional data model. The method can make the printing model finished product more convenient to take out from the forming platform bottom plate by performing shrinkage processing on the bottom edges of the three-dimensional data model of the printing object.

Description

TECHNICAL FIELD

[0001] The present application mainly relates to the field of three-dimensional printing technology, in particular to a light-curing three-dimensional printing method, system, device and computer readable medium. BACKGROUND

[0002] In light-curing three-dimensional printing, the printing process is carried out on a forming platform, and after printing is completed, the printed model product needs to be taken out from the forming platform. Some printed models can be placed in the air on the forming platform using support tools, which facilitates taking out after printing is completed. However, some printed models cannot be placed in the air using support tools, and can only be placed directly on the forming platform bottom plate. In this way, it is possible that the printed model product and the forming platform are combined too tightly, which makes it difficult to use a spatula or other tools to cut in and take out after printing is completed. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a light-curing three-dimensional printing method, system, device and computer readable medium, which can conveniently take out the printed model product from the forming platform bottom plate.

[0004] To solve the above technical problem, the present application provides a light-curing three-dimensional printing method, comprising: obtaining a three-dimensional data model of a printed object; dividing the three-dimensional data model into multiple layers; and performing shrinkage processing on the edges of a preset number of bottom layers of the three-dimensional data model in at least one horizontal direction.

[0005] Optionally, the shrinkage distance of each bottom layer decreases layer by layer from the bottom layer upwards.

[0006] Optionally, the preset number is less than or equal to the quotient of the light penetration depth divided by the average layer thickness of the bottom layers of the preset number.

[0007] Optionally, the layer thickness of each layer of the preset number of bottom layers is equal.

[0008] Optionally, the shrinkage distance of each bottom layer from the bottom layer upwards is in a linear relationship.

[0009] Optionally, the smallest shrinkage distance of one layer and the shrinkage distance of the bottom layer after shrinkage are on a straight line, and the smallest positive angle formed by the intersection of the straight line and the bottom horizontal plane of the three-dimensional data model is between 15-40 degrees.

[0010] To solve the above technical problem, the present application also provides a light-curing three-dimensional printing system, comprising: a model acquisition module for obtaining a three-dimensional data model of a printed object; a layering module for dividing the three-dimensional data model into multiple layers; and a shrinkage module for performing shrinkage processing on the edges of a preset number of bottom layers of the three-dimensional data model in at least one horizontal direction.

[0011] To solve the above technical problems, the present application also provides a light-cured three-dimensional printing device, comprising a printing mechanism and a controller, the controller being configured to control the printing mechanism to perform the light-cured three-dimensional printing method as described above.

[0012] To solve the above technical problems, the present application also provides a computer readable medium storing computer program codes, the computer program codes, when executed by a processor, implementing the light-cured three-dimensional printing method as described above.

[0013] Compared with the prior art, the present application has the following advantages:

[0014] By performing the shrinkage processing on the bottom edge of the three-dimensional data model of the printing object, the printing model finished product can be more conveniently taken out from the forming platform bottom plate. BRIEF DESCRIPTION OF DRAWINGS

[0015] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated in and constitute a part of this application, illustrate embodiments of the present application, and together with the description serve to explain the principles of the present application. In the drawings:

[0016] Figure 1 Fig. 1 shows a flowchart of a light-cured three-dimensional printing method according to an embodiment of the present application.

[0017] Figure 2 Fig. 2 shows a schematic diagram of a light-cured three-dimensional printing model according to an embodiment of the present application.

[0018] Figure 3 Fig. 3 shows a flowchart of a light-cured three-dimensional printing method according to another embodiment of the present application.

[0019] Figure 4 Fig. 4 shows a schematic diagram of a bottom layer edge shrinkage of a light-cured three-dimensional printing model according to an embodiment of the present application.

[0020] Figure 5A Fig. 5 shows a schematic diagram of an internal structure of a light-cured three-dimensional printing model according to an embodiment of the present application.

[0021] Figure 5B Fig. 6 shows a schematic diagram of an internal structure of a light-cured three-dimensional printing model according to another embodiment of the present application.

[0022] Figure 5C Fig. 7 shows a schematic diagram of an internal structure of a light-cured three-dimensional printing model according to yet another embodiment of the present application.

[0023] Figure 6 Fig. 8 shows a block diagram of a light-cured three-dimensional printing system according to an embodiment of the present application.

[0024] Figure 7 A controller architecture diagram of a light-cured three-dimensional printing device is shown according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the following will describe the specific embodiments of the present application in detail with reference to the accompanying drawings.

[0026] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application, however, can be practiced without the specific details. In other instances, well-known methods have not been described in detail in order not to unnecessarily obscure aspects of the present application.

[0027] As used in this application and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a" or "the" element or steps of the method includes an embodiment having one or more of them. Similarly, for example, the phrases "comprising a" or "comprising the" element can include one or more of them.

[0028] It will be understood that when a part is referred to as being "on" or "connected to" or "coupled with" or "contacting" another part, it can be directly on, connected, coupled, or contacting the other part, or intervening parts can be present. In contrast, when an element is referred to as being "directly on," "directly connected to," "directly coupled with," or "directly contacting" another element, there are no intervening parts. Similarly, when a first element is referred to as being "electrically contacting" or "electrically coupled with" a second element, there is an electrical path between the first element and the second element that allows current to flow. The electrical path can include capacitors, coupled inductors, and / or other components that allow current to flow, even if there is no direct contact between conductive components.

[0029] Figure 1A basic structure of a light-curing three dimensional (3D) printing device according to an embodiment of the present application is shown. The 3D printing device 100 includes a vat 110 for containing a light-curing resin, an image exposure system 120 for curing the light-curing resin, and a lifting platform 130 for connecting the formed workpiece. The lifting platform 130 can move up and down in a vertical direction. The image exposure system 120 is located above the vat 110 and can irradiate a light beam image to cause a layer of the light-curing resin on the liquid surface of the vat 110 to be cured. After the image exposure system 120 irradiates a light beam image to cause a layer of the light-curing resin to be cured each time, the lifting platform 130 causes the formed layer of the light-curing resin to be slightly lowered and spreads the light-curing resin on the top surface of the cured workpiece uniformly by a squeegee 131, waiting for the next irradiation. The squeegee 131 can move in a horizontal direction. Such a cycle is repeated to obtain a three dimensional workpiece formed layer by layer.

[0030] The image exposure system 120 can irradiate a light beam image to the light-curing resin to form a desired exposure pattern. The image exposure system 120 can use various known techniques capable of forming a light beam image, which are not limited in the present application.

[0031] For example, in one embodiment, the image exposure system 120 can use a Digital Light Procession (DLP) projection technology. The DLP projection imaging technology is realized by using a Digital Micromirror Device (DMD) to control the reflection of light. The Digital Micromirror Device can be regarded as a mirror. The mirror is composed of hundreds of thousands or even millions of micro-mirrors. Each micro-mirror represents a pixel, and the image is composed of these pixels.

[0032] In another embodiment, the image exposure system 120 can also use a Liquid Crystal Display (LCD) projection technology. The LCD panel contains a large number of pixels, and the polarization direction of polarized light of each pixel can be controlled individually. In combination with the polarized light filters on both sides of the LCD panel, it can be controlled whether the light of a certain pixel passes through, so the light beam passing through the LCD panel system is imaged.

[0033] The input of the light-curing 3D printing device 100 is a three dimensional data model of a printing object, which is then decomposed into a plurality of two dimensional images. Each two dimensional image represents a layer of the printing object. The light-curing 3D printing device 100 sends these two dimensional images to the image exposure system 120, which projects them.

[0034] Figure 2A schematic diagram of a light-cured three-dimensional printing model is shown according to an embodiment of the present application. In the present application, a light source top-mounted light-cured three-dimensional printing device is taken as an example for illustration. It should be noted that the light-cured three-dimensional printing method involved in the present application is also applicable to a light source bottom-mounted light-cured three-dimensional printing device, which will not be described here. As shown in Figure 2 , the printing model can be divided into multiple layers, and the layer thickness of each layer is D; the light beam of the 3D printing device penetrates into the resin with a depth of H. The light penetration depth H should be greater than the layer thickness D, otherwise the part of the layer that is greater than the light penetration depth H cannot receive light beam irradiation. The material strength of the finished product of the light-cured three-dimensional printing model is positively correlated with the irradiation intensity received by the light-cured resin. That is, the material strength of the area with higher irradiation intensity will be higher than that of the area with lower irradiation intensity.

[0035] Figure 3 A flowchart of a light-cured three-dimensional printing method is shown according to an embodiment of the present application. As shown in Figure 3 , the light-cured three-dimensional printing method includes the following steps:

[0036] Step 301, obtaining a three-dimensional data model of a printing object;

[0037] Step 302, dividing the three-dimensional data model into multiple layers; and

[0038] Step 303, performing shrinkage processing on the edges of a preset number of bottom layers of the three-dimensional data model in at least one horizontal direction.

[0039] The three-dimensional data model obtained in step 301 is the original three-dimensional data model of the printing object, which has not undergone bottom edge shrinkage processing.

[0040] In step 303, the light-cured 3D printing device performs shrinkage processing on the edges of a preset number of bottom layers of the three-dimensional data model in at least one horizontal direction. Shrinkage processing refers to the edges of a layer of the three-dimensional data model being shrunk in the horizontal direction towards the inside of the three-dimensional data model by a certain distance. Shrinkage processing can be performed in one horizontal direction, or in multiple horizontal directions as needed, which is not limited in the present application. The shrinkage distance can be adjusted by the operator according to factors such as printing material, which is not limited in the present application.

[0041] Figure 4 A bottom layer edge shrinkage schematic diagram of a light-cured three-dimensional printing model is shown according to an embodiment of the present application. As shown in Figure 4As shown, the three-dimensional data model has a preset number N of bottom layers, from the bottom layer to the top layer, they are D1, D2, …, Dn respectively; the shrinkage distance X (dashed portion) of each bottom layer is X1, X2, …, Xn respectively, where n = 1, 2, …, N. After the shrinkage processing of the bottom layer, the image exposure system of the light-curing 3D printing equipment no longer irradiates the shrunk part when printing the bottom layer. Because the layer thickness D of each layer is less than the light penetration depth H, when a layer is irradiated, if one or more layers below the layer are still within the range of the light penetration depth H, they can still receive irradiation. When the light beam passes through the light-curing resin, its intensity gradually decreases with the increase of the penetration distance. Therefore, compared with the current printing layer that is being irradiated, the layers below the layer receive lower light intensity and the cured light-curing resin has lower hardness. That is, Figure 4 The light-curing resin in the shrinkage distance X range of each bottom layer in the middle can still receive irradiation when the previous layer is irradiated, but the received light intensity is lower than normal printing, and the cured hardness is correspondingly lower. Therefore, the three-dimensional model product after the bottom shrinkage processing is still complete in appearance, but the material strength of the bottom edge area is lower and the combination with the forming platform bottom plate is weaker, facilitating cutting for taking out. The cutting for taking out can be taking out using a shovel or other tools, and the application does not limit the tools used for cutting for taking out.

[0042] Figure 5A The internal structure schematic diagram of the light-curing three-dimensional printing model according to an embodiment of the application is shown. Figure 5A The black area and the gray area in the middle constitute the three-dimensional model, where the black area is the normal printing area and the gray area is the shrinkage processing area. Compared with the black area, the material strength of the gray area is lower and the combination with the forming platform bottom plate is weaker. Therefore, when using a shovel or other cutting tools to take out with the gray area as the cutting position, it can be easily cut in. Figure 5B The internal structure schematic diagram of the light-curing three-dimensional printing model according to another embodiment of the application is shown. Similar to the embodiment of Figure 5A , Figure 5B The black area and the gray area in the middle constitute the three-dimensional model, where the black area is the normal printing area and the gray area is the shrinkage processing area. Figure 5A Similar to Figure 5B As an example of the internal structure of the three-dimensional printing model, the application does not limit the shape of the shrinkage area.

[0043] Optionally, the preset number N can be less than or equal to the quotient of the light penetration depth H divided by the average layer thickness of the bottom layer of the preset number, that is, ​Optionally, a preset number of bottom layers each have an equal layer thickness D. When the layer thicknesses of the bottom layers are equal, the average layer thickness is... The number of bottom layers is equal to the thickness D of each layer. In other words, the preset number N can be less than or equal to the quotient of the light transmission depth H divided by the thickness D of each bottom layer, i.e., N≦H / D. By limiting the number of bottom layers based on the light transmission depth and the average thickness of the bottom layers, it can be ensured that all bottom layers receive irradiation, avoiding the problem of some shrinkage areas of the bottom layers failing to cure due to insufficient irradiation.

[0044] Optionally, the contraction distance X of each bottom layer can be gradually reduced from the bottom layer upwards. By gradually reducing the contraction distance X from the bottom layer upwards, the material strength of a region with a cross-section approximately resembling a triangle at the edge of the 3D model will be lower, making it easier to cut and remove parts.

[0045] Optionally, the contraction distance X of each bottom layer from the bottom layer upwards can be linearly related. In this case, the cross-section of the low-intensity region at the edge of the 3D model is closer to a triangle, making it easier to cut and extract parts. Figure 5C A schematic diagram of the internal structure of a photopolymer 3D printed model according to yet another embodiment of this application is shown. Figure 5A and 5B The implementation examples are similar, Figure 5C The black and gray areas in the image constitute the 3D model. The black areas are the normal printing areas, while the gray areas are the areas undergoing shrinkage processing. At this point, the shape of the shrinkage processing area is closer to a triangle, making it easier to cut and remove the part.

[0046] Preferably, the minimum positive angle formed by the intersection of the straight line containing the contracted edge of the layer with the smallest contraction distance and the contracted edge of the bottom layer with the bottom horizontal plane of the 3D data model can be between 15 and 40 degrees. Figure 4 Taking the 3D data model shown as an example, layer Dn is the layer with the smallest shrinkage distance. Point A on its edge after shrinkage and point B on the edge of the bottom layer D1 after shrinkage are on a straight line. This straight line intersects the bottom horizontal plane to form the smallest positive angle α. When the angle α is between 15 and 40 degrees, it is most convenient to cut in and remove the part.

[0047] After completing the shrinkage process described above for the bottom layer of the 3D data model, the photopolymer 3D printer can begin printing the 3D model layer by layer. The printing process of the photopolymer 3D printer will not be described in detail here.

[0048] Figure 6 A block diagram of a photopolymerization 3D printing system according to an embodiment of this application is shown. Figure 6As shown, the light-curing three-dimensional printing system 400 comprises a model obtaining module 410, a layering module 420 and a shrinking module 430. The model obtaining module 410 is configured to obtain a three-dimensional data model of a printing object; the layering module 420 is configured to divide the three-dimensional data model into multiple layers; and the shrinking module 430 is configured to perform shrinking processing on edges in at least one horizontal direction of a preset number of bottom layers of the three-dimensional data model. The steps performed by the above modules can refer to the descriptions of steps 301-303 in the foregoing embodiments, which will not be described here in detail.

[0049] The present application also provides a light-curing three-dimensional printing device, comprising a printing mechanism and a controller, wherein the controller is configured to control the printing mechanism to perform the light-curing three-dimensional printing method as described above.

[0050] Figure 7 A controller architecture diagram of a light-curing three-dimensional printing device according to an embodiment of the present application is shown. Referring to Figure 7 As shown, the controller 700 of the light-curing three-dimensional printing device can comprise a memory 710 and a processor 720. The memory 710 is configured to store instructions executable by the processor 720. The processor 720 is configured to execute the instructions to implement the light-curing three-dimensional printing method as described above.

[0051] In some embodiments of the present application, the controller 700 further comprises a communication port 730, an input / output device 740 and an internal communication bus 750.

[0052] The communication port 730 can be responsible for data communication between the controller 700 and external devices (not shown). The input / output device 740 can support input / output data flow and image flow between the controller 700 and other components. As an example, the input / output device 740 can comprise one or more of the following components: keyboard, mouse, camera, display, scanner, touch screen, handwriting input pad and microphone, etc. input devices or any combination thereof. The input / output device 740 can input various numerical data and various non-numerical data such as graphics, images, sound, etc. to the controller 700. The internal communication bus 750 can realize data communication between components in the controller 700.

[0053] It can be understood that the light-curing three-dimensional printing method of the present application is not limited to being implemented by one light-curing three-dimensional printing device, but can be cooperatively implemented by multiple on-line light-curing three-dimensional printing devices. The on-line light-curing three-dimensional printing devices can be connected and communicated through a local area network or a wide area network.

[0054] Other implementation details of the three-dimensional printing device of the present embodiment can refer to the descriptions of the three-dimensional printing device in the foregoing embodiments. Figures 1 to 6 The described embodiments will not be described here in detail.

[0055] The application also provides a computer readable medium storing computer program code which, when executed by a processor, implements the above-mentioned method for light-cured three-dimensional printing.

[0056] In an embodiment of the application, the computer program code can be executed by the processor 720 in the controller 700 to implement the above-mentioned method for light-cured three-dimensional printing. Figure 7 In an embodiment of the application, the computer program code can be executed by the processor 720 in the controller 700 to implement the above-mentioned method for light-cured three-dimensional printing.

[0057] For example, a method for light-cured three-dimensional printing of the application can be implemented as a program for light-cured three-dimensional printing, saved in the memory 710 and loaded into the processor 720 for execution to implement the method of the application.

[0058] When the method for light-cured three-dimensional printing is implemented as a computer program, it can also be stored in a computer readable storage medium as an article of manufacture. For example, the computer readable storage medium can include, but is not limited to, magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips), optical disks (e.g., compact disk (CD), digital versatile disk (DVD)), smart cards, and flash memory devices (e.g., electrically erasable programmable read-only memory (EPROM), card, stick, key drive). In addition, the various storage mediums described herein can represent one or more devices and / or other machine-readable mediums for storing information. The term "machine-readable medium" can include, but is not limited to, wireless channels and various other mediums (and / or storage mediums) capable of storing, containing, and / or carrying code and / or instructions and / or data.

[0059] The above has described the basic concepts, and it is obvious that the above-mentioned application disclosure is only as an example and does not constitute a limitation on the application for those skilled in the art. Although it is not explicitly stated here, those skilled in the art can make various modifications, improvements and corrections to the application. Such modifications, improvements and corrections are suggested in the application, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of the application.

[0060] Meanwhile, specific words are used in the application to describe the embodiments of the application. As "one embodiment", "an embodiment", and / or "some embodiments" means a certain feature, structure or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that the "an embodiment" or "one embodiment" or "an alternative embodiment" mentioned in different places in the specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the application can be properly combined.

[0061] Some aspects of the methods and systems of the present application can be performed entirely in hardware, entirely in software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software can be referred to as a "block," "module," "engine," "unit," "component," or "system." A 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. Furthermore, aspects of the present application can be presented in a computer program product, located in one or more computer readable media, that includes computer readable program code. For example, the computer readable media can include, but is not limited to, magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips...), optical disks (e.g., compact disk (CD), digital versatile disk (DVD)...), smart cards, and flash memory devices (e.g., card, stick, key drive...).

[0062] A computer readable signal medium can include a propagated data signal with computer program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal can take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium can be any computer readable medium that can be selected to communicate a program code embodied therein to a device for execution. A computer readable program code embodied on a computer readable signal medium can be communicated by any of a variety of means, including, but not limited to, wireless, wire line, optical fiber cable, RF, or any suitable combination thereof.

[0063] In addition, the order of execution or performance of the operations of the aspects of the application illustrated and described herein is not essential, unless otherwise specified. That is, the operations can be performed in any order, unless otherwise specified, and the examples described herein are illustrative terms that do not limit the scope of the application. For example, although the above-described system components can be implemented by hardware devices, they can also be implemented by software solutions only, such as installing the described system on an existing server or mobile device.

[0064] For simplicity and to help with understanding of one or more embodiments of the application, the description of embodiments of the application above sometimes refers to a combination of features in one embodiment, drawing, or description of an embodiment. This method of disclosure is not to be interpreted as reflecting an intention that the application requires more features than are explicitly mentioned in each claim. Indeed, reference to such an embodiment of the application does not necessarily encompass all inventive aspects of the application, and the claims can refer to various embodiments of the application in each claim, in an independent claim dependent on one or more other claims, in dependent claims dependent on a single independent claim, or in dependent claims each dependent on two or more other claims. In practice, the claims can be dependent on one or more features in a combination of independent claims and dependent claims.

[0065] Some embodiments use numerals to describe components, quantities of attributes. It should be understood that such numerals used in the description of embodiments are in some examples modified by the adjectives "about", "approximately", or "substantially". Unless otherwise stated, "about", "approximately", or "substantially" indicate that the described numeral can vary ±20%. Accordingly, numerical parameters in the description and claims are approximations, and can vary depending upon the requirements of the particular embodiments. In some embodiments, numerical parameters are determined by the particular limits of the measurement devices used. Although the numerical ranges and parameters setting forth the broad scope of the application in some embodiments are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. The numerical values set forth in the specific examples are provided to be as precise as reasonably possible. However, some variations may

[0066] While the application has been described with reference to the currently preferred embodiments, those skilled in the art will recognize that various changes can be made in form and detail without departing from the spirit and the scope of the application. Therefore, although the application has been described with reference to particular embodiments, the description is by way of example only and the application is not limited to these embodiments.

Claims

1. A method for light-curing three-dimensional printing, comprising: obtaining a three-dimensional data model of a printing object; dividing the three-dimensional data model into multiple layers; performing a shrinkage process on edges of a preset number of bottom layers of the three-dimensional data model in at least one horizontal direction, the shrinkage process comprising shrinking the edges in the horizontal direction by a preset distance towards an inside direction of the three-dimensional data model; and printing the three-dimensional data model, wherein after the shrinkage process on the bottom layers, the areas of the bottom layers that have been subjected to the shrinkage process are no longer irradiated when the bottom layers are printed; each layer of the multiple layers has a layer thickness less than a light penetration depth, wherein the light penetration depth is a penetration depth of a light beam in a light-curing resin, when a layer is irradiated, if one or more layers below the layer are still within the range of the light penetration depth, the one or more layers can still receive irradiation, wherein when the light beam penetrates the light-curing resin, the intensity of the light beam gradually decreases with the increase of the penetration distance, compared with a current printing layer that is being irradiated, the layers below the current printing layer receive lower light intensity and have lower hardness after curing; the light-curing resin of each bottom layer within the shrinkage distance range can still receive irradiation when the previous layer is irradiated, but the received light intensity is lower than normal printing, and the hardness after curing is correspondingly lower; the three-dimensional model product after the shrinkage process is still complete in appearance, and the material strength of the bottom edge area of the three-dimensional model product is lower. The shrinkage distance of each bottom layer decreases layer by layer from the bottom layer upwards.

2. The method of claim 1, wherein, The preset number is less than or equal to the quotient of the light penetration depth divided by the average layer thickness of the preset number of bottom layers.

3. The method of claim 1, wherein, The layer thickness of each layer of the preset number of bottom layers is equal.

4. The method of claim 1, wherein, The shrinkage distance of each bottom layer from the bottom layer upwards is in a linear relationship.

5. The method of claim 2, wherein, The smallest positive angle between the straight line formed by the shrunk edge of the layer with the smallest shrinkage distance and the shrunk edge of the bottom layer and the bottom horizontal plane of the three-dimensional data model is between 15-40 degrees.

6. The method of claim 1, wherein, 7.A light-curing three-dimensional printing system for performing the method of claims 1-6, comprising: a model obtaining module for obtaining a three-dimensional data model of a printing object; a layering module for dividing the three-dimensional data model into multiple layers; and a shrinkage module for performing a shrinkage process on edges of a preset number of bottom layers of the three-dimensional data model in at least one horizontal direction, the shrinkage process comprising shrinking the edges in the horizontal direction by a preset distance towards an inside direction of the three-dimensional data model. ​ ​ An image exposure system for printing the three-dimensional data model, wherein after the shrinkage processing of the bottom layer, the region of the bottom layer that has been subjected to the shrinkage processing is no longer irradiated when the bottom layer is printed; the thickness of each layer in the plurality of layers is less than the light penetration depth, wherein the light penetration depth is the penetration depth of a light beam in a photocuring resin, when a layer is irradiated, if one or more layers below the layer are still within the range of the light penetration depth, the one or more layers can still receive irradiation, wherein when the light beam penetrates the photocuring resin, the intensity of the light beam gradually decreases with the increase of the penetration distance, compared with the current printing layer that is being irradiated, the layers below the current printing layer receive lower light intensity and have lower hardness after curing; the photocuring resin of each bottom layer within the shrinkage distance range can still receive irradiation when the previous layer is irradiated, but the received light intensity is lower than normal printing, and the hardness after curing is correspondingly lower; the three-dimensional model product after the shrinkage processing is still complete in appearance, and the material strength of the bottom edge region of the three-dimensional model product is lower.

8. A photocuring three-dimensional printing device, comprising a printing mechanism and a controller, the controller being configured to control the printing mechanism to perform the photocuring three-dimensional printing method according to any one of claims 1-6.

9. A computer readable medium storing computer program code which, when executed by a processor, implements the photocuring three-dimensional printing method according to any one of claims 1-6.

Images