Three-dimensional printing method and three-dimensional printing apparatus

Abstract

The application discloses a three-dimensional printing method and a three-dimensional printing device for manufacturing a target object. The three-dimensional printing method comprises: forming a first plurality of layers of the target object using a base material; and forming a second plurality of layers of the target object using a first material and a second material different from the first material, specifically comprising: solidifying the first material to form a first part of a first layer in the second plurality of layers; solidifying the second material to form a second part of the first layer in the second plurality of layers; solidifying the first material to form a first part of a second layer in the second plurality of layers on the first part of the first layer; solidifying the second material to form a second part of the second layer in the second plurality of layers on the second part of the first layer; and repeating the steps to form the second plurality of layers of the target object. The application can realize the printing of at least two materials in the same layer by the above method, so as to achieve the printing effect of multi-materials (such as color).

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and more specifically, to a 3D printing method and a 3D printing device. Background Technology

[0002] Additive manufacturing technologies come in various types, such as DLP, LCD, SLA, and FDM. To obtain a target object with one part composed of the same material and another part composed of multiple materials (e.g., a cylindrical object with a black base, a left half made of red material, and a right half made of blue material), FDM can print the object using filaments of black, red, and blue materials. However, the printing precision of FDM will exhibit a noticeable stack of multiple layers, which is easily identifiable by the user. Photopolymerization technologies (e.g., DLP, LCD) allow for the generation of high-precision target objects, where the stacked layers are difficult for the user to discern, resulting in good print surface quality. However, photopolymerization technology currently only allows the construction of a first layer composed of a first material and a second layer on top of that first layer composed of a second material different from the first material; achieving printing of two or more materials on the same layer remains challenging. Summary of the Invention

[0003] According to one aspect of the present invention, a three-dimensional printing method for manufacturing a target object is provided, the target object comprising a first plurality of layers and a second plurality of layers, comprising: forming the first plurality of layers (1~m, m≥2) of the target object using a base material; and

[0004] The target object is formed using a first material and a second material different from the first material, comprising a second plurality of layers (1 to n, n ≥ 3) including:

[0005] (a) Curing a first material to form a first portion of a first layer in a second plurality of layers, the first portion of the first layer having a first thickness;

[0006] (b) Curing the second material to form a second portion of the first layer in a second plurality of layers, the second portion of the first layer having a second thickness greater than the first thickness;

[0007] (c) Curing the first material to form a first portion of a second layer of a second plurality of layers on a first portion of the first layer, wherein the total thickness of the first portion of the first material is greater than the total thickness of the second portion of the second material;

[0008] (d) Curing the second material to form a second portion of a second layer of a second plurality of layers on a second portion of the first layer, wherein the total thickness of the second portion formed by the second material is greater than the total thickness of the first portion formed by the first material;

[0009] (e) Repeat steps (c) and (d) to form a second or more layers of the target object.

[0010] In some embodiments, the above-described 3D printing method includes:

[0011] - Before forming the first plurality of layers, form the second plurality of layers; or

[0012] - The first multiple layers are formed before the second multiple layers are formed.

[0013] In some embodiments, the first thickness is 1%-99% of the second thickness, preferably 30%-70%, and more preferably 40%-60%.

[0014] In some embodiments, the first thickness is 50% of the second thickness.

[0015] In some embodiments, the second thickness is 5~300μm, preferably 20~200μm, more preferably 50~150μm, and even more preferably 60~120μm.

[0016] In some embodiments, the base material is:

[0017] - Same as the first material, or

[0018] - Same as the second material, or

[0019] - Unlike the first and second materials.

[0020] In some embodiments, the color of the first material is different from the color of the second material.

[0021] In some embodiments, the base material includes at least one material or a mixture of multiple materials.

[0022] In some embodiments, in step (c), the total thickness of the first portion made of the first material is equal to the sum of the first thickness and the second thickness.

[0023] In some embodiments, in step (d), the total thickness of the second portion made of the second material is twice the second thickness.

[0024] In some embodiments, a first portion of the second layer is formed on a first portion of the first layer along a vertical direction or a Z-axis direction, and wherein the first portion of the first layer and the second portion of the second layer are spaced apart along a direction perpendicular to the vertical direction.

[0025] In some embodiments, a first portion of the second layer is formed on a first portion of the first layer in a vertical direction, and in a plane perpendicular to the vertical direction, the first portion at least partially surrounds the second portion.

[0026] In some embodiments, a first material is cured in a first region, and a second material is cured in a second region spaced apart from the first region.

[0027] In some embodiments, a first region is defined by a container for containing a first material, a second region is defined by a container for containing a second material, and wherein the containers have at least a partially transparent bottom.

[0028] In some embodiments, a first region is defined by a plate-like element for carrying a first material, a second region is defined by a plate-like element for carrying a second material, and wherein the plate-like element has a bottom that is at least partially transparent.

[0029] In some embodiments, the first material is applied via a nozzle to a plate-like element used to carry the first material, and / or

[0030] The second material is applied to the plate-shaped element that carries the second material through a nozzle.

[0031] In some embodiments, the above-described 3D printing method further includes:

[0032] After step (c), clean the target object, and / or

[0033] The target object is cleaned after step (d).

[0034] In some embodiments, cleaning includes at least one of a rotational forming platform, wiping a three-dimensional object, applying airflow to the three-dimensional object, and surrounding the target object with an adsorbent to remove excess printing material.

[0035] In some embodiments, the above-described 3D printing method further includes providing at least a third region, wherein the material applied in the third region is the same as or different from at least one of the first material and the second material.

[0036] In some embodiments, the second portion of the second plurality of layers has a uniform layer thickness.

[0037] In some embodiments, a second portion of the second plurality of layers at least partially surrounds a first portion of the second plurality of layers.

[0038] According to another aspect of the present invention, a three-dimensional printing method for manufacturing a target object is provided, the target object comprising a first plurality of layers and a second plurality of layers, including:

[0039] The target object is formed using a base material, creating the first multiple layers (1~m, m≥2); and

[0040] The target object is formed using a first material and a second material different from the first material, comprising a second plurality of layers (1 to n, n ≥ 3) including:

[0041] (a) Curing a first material to form a first portion of a first layer in a second plurality of layers, the first portion of the first layer having a first thickness;

[0042] (b) Curing the second material to form a second portion of the first layer in a second plurality of layers, the second portion of the first layer having a second thickness greater than the first thickness;

[0043] (c) Curing the first material to form a first portion of a second layer of a second plurality of layers on a first portion of the first layer, wherein the total thickness of the first portion of the first material is greater than the total thickness of the second portion of the second material;

[0044] (d) Curing the second material to form a second portion of a second layer of a second plurality of layers on a second portion of the first layer, wherein the total thickness of the second portion formed by the second material is greater than the total thickness of the first portion formed by the first material;

[0045] (e) Repeat steps (c) and (d) to form a second or more layers of the target object.

[0046] The target object is cleaned after at least one of steps (a) to (d).

[0047] According to another aspect of the present invention, a three-dimensional printing apparatus is provided for manufacturing a three-dimensional target object, the target object comprising a first plurality of layers (1~m, m≥2) and a second plurality of layers (1~n, n≥3), the second plurality of layers comprising at least two materials, the three-dimensional printing apparatus comprising:

[0048] Material holding mechanism;

[0049] A molding platform configured to adhere three-dimensional target objects;

[0050] Radiation device for radiating light onto the material holding mechanism; and

[0051] A drive mechanism, wherein the drive mechanism is configured to move at least one of a molding platform and a material holding mechanism;

[0052] The 3D printing equipment is configured as follows:

[0053] (a) By driving the base material areas of the molding platform and the material holding mechanism, the base material is aligned and solidified by the radiation device to form the first multiple layers of the target object on the molding platform;

[0054] (b) By means of a drive mechanism, the first material area of ​​the forming platform and the material holding mechanism are aligned, and the first material is cured by means of a radiation device to form a first portion of the first layer of a second plurality of layers, the first portion of the first layer having a first thickness;

[0055] (c) By driving the second material region of the molding platform and the material holding mechanism, the second material is aligned and cured by the radiation device to form a second part of the first layer in a second plurality of layers, the second part of the first layer having a second thickness greater than the first thickness, wherein the first material and the second material are different;

[0056] (d) By driving the first material area of ​​the molding platform and the material holding mechanism, the first material is aligned and cured by the radiation device to form the first part of the second layer of the second plurality of layers on the first part of the first layer, wherein the total thickness of the first part composed of the first material is greater than the total thickness of the second part composed of the second material.

[0057] (e) By driving the second material area of ​​the molding platform and the material holding mechanism, the second material is aligned and cured by the radiation device to form the second part of the second layer of the second plurality of layers on the second part of the first layer, wherein the total thickness of the second part composed of the second material is greater than the total thickness of the first part composed of the first material.

[0058] Repeat steps (b)-(e) to form a second or more layers of the target object.

[0059] This application provides a 3D printing method for manufacturing a target object, the target object comprising a first plurality of layers and a second plurality of layers. The 3D printing method includes: forming the first plurality of layers of the target object using a base material; and forming the second plurality of layers of the target object using a first material and a second material different from the first material. Specifically, this includes: curing the first material to form a first portion of the first layer in the second plurality of layers; curing the second material to form a second portion of the first layer in the second plurality of layers; curing the first material to form a first portion of the second layer in the second plurality of layers on the first portion of the first layer; curing the second material to form a second portion of the second layer in the second plurality of layers on the second portion of the first layer; and repeating the steps to form the second plurality of layers of the target object. This application, through the above method, can achieve printing at least two materials on the same layer, thereby achieving a multi-material (e.g., color) printing effect. The printing equipment provided by this application can implement the above 3D printing method, thereby being used to manufacture multi-material (e.g., color) models. Attached Figure Description

[0060] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0061] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0062] Figure 1 A 3D printing apparatus according to some embodiments of the present invention is shown;

[0063] Figure 2A This is a schematic diagram of an object to be printed according to an embodiment of the present invention;

[0064] Figure 2B This is a schematic diagram of a slice of an object to be printed according to an embodiment of the present invention;

[0065] Figures 3A-3F This is a schematic diagram of the printing of an object to be printed according to an embodiment of the present invention;

[0066] Figure 4 This is a schematic diagram of another object to be printed according to an embodiment of the present invention;

[0067] Figure 5A-5G This is a schematic diagram of the printing state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention;

[0068] Figures 6A-6C This is a schematic diagram of the printing state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention;

[0069] Figures 7A-7D This is a schematic diagram of the printing state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention;

[0070] Figure 8 This invention provides a schematic diagram illustrating the printing process involving three materials according to an embodiment of the invention.

[0071] Figure 9 This is a schematic diagram of another object to be printed according to an embodiment of the present invention;

[0072] Figure 10A A schematic diagram of an object being formed according to some embodiments is shown;

[0073] Figure 10B A tooth model according to some embodiments is shown;

[0074] Figure 10C A schematic diagram of an object being formed according to some embodiments is shown;

[0075] Figure 11 A schematic diagram of an object being formed according to some embodiments is shown.

[0076] In the accompanying drawings, the same or similar reference numerals represent the same or similar elements or components. Detailed Implementation

[0077] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0078] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to refer to similar or identical objects and are not necessarily used to describe a specific order or priority, unless otherwise indicated. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, or system, product, or apparatus comprising a series of steps is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0079] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0080] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to refer to similar or identical objects and are not necessarily used to describe a specific order or priority, unless otherwise indicated. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, or system, product, or apparatus comprising a series of steps is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0081] In 3D printing, a 3D model (data model) of the target object (printed part, printed model) to be manufactured is first created. Then, the 3D model of the target object is sliced ​​layer by layer. Printing can start from the first slice. After the first slice is printed, each slice is printed sequentially until a complete 3D model of the printed part is obtained, which is the final three-dimensional object, i.e., the target object. In some printing technologies, when printing each slice, light can be projected onto the printing area in a material holding mechanism (e.g., a tray, trough, container, etc.) filled with photocurable material, based on the shape or outline of the slice. Under the illumination of the light emitted by the light-emitting mechanism, the photocurable material will solidify between the forming platform and the material holding mechanism (including the release film) to form a solid or semi-solid polymer. Then, the solid or semi-solid polymer can be separated from the material holding mechanism, and the next slice can be printed.

[0082] The inventors discovered that in projection printing, such as DLP and LCD printing, only single-material or single-color printing is typically possible. Obtaining multi-color or multi-material objects with different properties in different locations (such as a sphere with some rigid and some flexible parts) is quite difficult. Usually, for multi-color printed models, the model is printed first, and then the colors are applied later. Alternatively, the different color parts of the model are marked, and then the different parts are separated into individual models, printed separately, and then assembled. These methods are time-consuming, labor-intensive, and lack precision control. Therefore, achieving one-step printing of target objects with multiple colors or requiring printing with multiple different materials has become a challenge.

[0083] Figure 1 A 3D printing apparatus according to some embodiments of the present invention is shown. For example... Figure 1 As shown, the 3D printing equipment 100 includes a radiation device 111, a forming platform 112 (also called a build platform), and a material holding mechanism 113. The radiation device (or optical unit) 111 projects light onto the material holding mechanism 113 to cure the printing material located on the material holding mechanism 113. The forming platform 112 has a forming surface, and the printing material between the forming surface of the forming platform 112 and the material holding mechanism 113 can be cured by light (e.g., UV light). The radiation device 111 can emit ultraviolet light of a predetermined wavelength (e.g., 385nm or 405nm), which penetrates at least a partially transparent bottom of the material holding mechanism 113 and cures the printing material (e.g., photosensitive resin) carried by the material holding mechanism 113. The material holding mechanism 113 is provided with a film, for example, a film with a light transmittance of 80% to 90%.

[0084] According to an embodiment of the present invention, an embodiment of a three-dimensional printing method for manufacturing a target object is provided, the target object comprising a first plurality of layers and a second plurality of layers, comprising: forming a first plurality of layers (1~m, m≥2) of the target object using a base material; and forming a second plurality of layers (1~n, n≥3) of the target object using a first material and a second material different from the first material, comprising: (a) curing the first material to form a first portion of the first layer in the second plurality of layers, the first portion of the first layer having a first thickness; (b) curing the second material to form a second portion of the first layer in the second plurality of layers, the second portion of the first layer having a second thickness greater than the first thickness; (c) curing the first material to form a first portion of the second layer in the second plurality of layers on the first portion of the first layer, wherein the total thickness of the first portion composed of the first material is greater than the total thickness of the second portion composed of the second material; (d) curing the second material to form a second portion of the second layer in the second plurality of layers on the second portion of the first layer, wherein the total thickness of the second portion composed of the second material is greater than the total thickness of the first portion composed of the first material; repeating steps (c) and (d) to form the second plurality of layers of the target object.

[0085] The first and second materials mentioned above can be materials of different textures, colors, or a combination of both. The target object mentioned above can be an object with regions or components of different colors. For example, the first and second materials may have different optical properties, such as their ability to absorb light and their translucency. Alternatively, the first and second materials may have different physical properties, such as color, elasticity, and yield strength. Furthermore, the first and second materials may have different chemical properties, such as having different compositions. The base material can be the same as the first material, the same as the second material, or different from both. The target object can be a tooth model, including white teeth and red gums. The target object can be an architectural model, including architectural components of various colors. The target object can be a figurine model, including components of various colors or materials. The target object can also be an industrial accessory model, including components of various colors or materials.

[0086] In this embodiment, the target object includes a first plurality of layers and a second plurality of layers. The first plurality of layers of the target object are formed using a base material; and the second plurality of layers of the target object are formed using a first material and a second material different from the first material. In one example, such as Figure 2A-2B As shown, Figure 2AThe target object 200 is shown. The target object 200 to be formed includes a first component 220, a second component 240, and a third component 260. The first component 220 is composed of a base material A, the second component 240 is composed of a first type of material B, and the third component 260 is composed of a second type of material C. The base material A can be the same as the first material B, the same as the second material C, or different from both the first material B and the second material C. For example, the base material A can be a sacrificial material used as a base plate or support to form the first or more layers of the target object. In this case, it is different from the components (which can be called the main materials) the first material B and the second material C used to form the second or more layers of the target object. The base material can be the same as either the first material B or the second material C. For example, when printing a denture model, first use pink material (base material) to print the first part of the gum that has not yet come into contact with the teeth. In the area where the gum meets and intersects with the teeth, continue printing the gum part with pink material (first material, which is also the base material at this point). Then use white or off-white material (second material) to print the teeth part. In this way, you can print denture models with multiple colors / different materials. Another example is printing a doll model. Taking a Mickey Mouse head model as an example, you can first use black material (base material) to print Mickey's two ears. In the area where the head meets and intersects with the face, continue printing the black part of the hair with black material (first material, which is also the base material at this point). Then use skin-colored or off-white material (second material) to print the face part.

[0087] Figure 2B This is a schematic diagram of the first and second layers of the target object 200, for reference. Figure 2B The target object 200 is sliced ​​to obtain a first plurality of sliced ​​layers (or slice images) and a second plurality of sliced ​​layers (or slice images). The first plurality of sliced ​​layers are used to form a first component 220, and the second plurality of sliced ​​layers are used to form a second component 240 and a third component 260. The first plurality of sliced ​​layers include a first layer 221, a second layer 222, ..., up to the m-th layer of the first component 220; m ≥ 3. The first plurality of layers of the target object 200 include only a single material, such as base material A, and the first component 220 of the target object can be obtained by continuously curing to form multiple layers 221. The first component 220 of the target object 200 is divided into multiple layers 221, for example, 200 layers. Each layer 221 has the same thickness, for example, 30 μm; or, it has different thicknesses, for example, some of the multiple layers 241 have a thickness of 30 μm, and some have a thickness of 50 μm. A larger thickness is beneficial for accelerating the printing speed of the target object, while a smaller thickness is beneficial for obtaining better surface quality.

[0088] The second plurality of layers comprises n layers, where n ≥ 3. Specifically, in some embodiments, the second plurality of layers are second plurality of slice layers (or slice diagrams). The first layer in the second plurality of slice layers includes a first layer 241 for the second component and a first layer 261 for the third component. The second layer in the second plurality of slice layers includes a second layer 242 for the second component and a second layer 262 for the third component. The third layer in the second plurality of slice layers includes a third layer 243 for the second component and a third layer 263 for the third component, ..., and the nth layer in the second plurality of slice layers includes an nth layer for the second component and an nth layer for the third component. The target object in the second plurality of layers comprises a second component made of a first material B and a third component made of a second material C. In order to manufacture the target object in the second plurality of layers (which is formed on the first component portion of the target object), the target object is layered to facilitate subsequent manufacturing.

[0089] In some embodiments, the first layer of the second plurality of layers includes a first slice layer 241 for the second component and a first slice layer 261 and a second slice layer 262 for the third component, that is, the first slice layer of the second component forms a first portion of the first layer of the second plurality of layers; the second layer of the second plurality of layers includes a second slice layer 242 and a third slice layer 243 for the second component, and a second slice layer 262 and a third slice layer for the third component, ..., the nth layer of the second plurality of layers includes an (n-1)th slice layer and an nth slice layer for the second component, and an (n-1)th slice layer and an nth slice layer for the third component.

[0090] like Figure 3A As shown, Figure 3A A 3D printing apparatus 300 is shown, on which a first part 320 of a target object is adhered. This first part is formed by layer-by-layer exposure curing using a base material based on a first plurality of slice layers. Figure 3A In the process, the first component 320 of the solidified target object leaves the material-holding mechanism containing material A. For simplification purposes, the radiation device and material-holding mechanism of the 3D printing equipment are omitted. Those skilled in the art will understand that the material-holding mechanism holds the corresponding material during the formation of the first component.

[0091] like Figure 3B-3FAs shown, the 3D printing equipment 300 continues to print a second plurality of layers of the target object. After the first part of the target object is printed, the first part 320 of the target object, which is made of material A, is adhered to the forming platform 312 (also called the build platform). At this time, the second plurality of layers of the target object continue to be formed on the first part to finally form the target object. Specifically, the second part 340 of the target object is formed using the first material, and the third part 360 of the target object is formed using a second material different from the first material.

[0092] In some embodiments, refer to Figure 3B After the first component is printed using the base material, at least one of the molding platform 312 or the material holding mechanism is driven by a drive mechanism (not shown) through an additive manufacturing system. The molding platform 312 moves to the area of ​​the material holding mechanism that carries the first material (material B) so that the molding platform 312 is aligned with the area carrying material B. The material B is then radiatively cured, allowing the material B carried by the material holding mechanism to be cured and adhered to the first component 320 on the molding platform 312 to form the first layer 341 of the second component, i.e., the first portion of the first layer of the second plurality of layers, which has a first thickness t1. The cured first layer 341 of the second component is separated from the material holding mechanism, and then the molding platform or the build platform 312 is moved to the area of ​​the material holding mechanism that carries the second material (material C) so that the molding platform 312 is aligned with the area carrying material C, as shown in the figure. Figure 3D The material C is radiation-cured, thereby allowing the material C carried by the material holding mechanism to be cured and adhered to the first component 320 on the molding platform 312 to form the first layer 361 of the third component, that is, the second part of the first layer in the second plurality of layers, the second part having a second thickness t2 greater than the first thickness, that is, t2 > t1.

[0093] In some embodiments, the first thickness t1 is 1%-99% of the second thickness t2, preferably 30%-70%, more preferably 40%-60%. In this case, the first layer 361 of the third component can be understood as a single slice, and during curing, the curing depth is greater than the first thickness t1 so that the cured thickness meets the requirements. In some embodiments, the first thickness t1 is 50% of the second thickness t2. In this case, the first layer 361 of the third component can be understood as consisting of two slices (i.e., 361 and 362). In some embodiments, the second thickness is 5-300 μm, preferably 20-200 μm, more preferably 50-150 μm, more preferably 60-120 μm. For example, 10-280 μm, 15-250 μm, 25-180 μm. In some embodiments, if the thickness of t1 is 25 μm and the thickness of t2 is 50 μm, then the overlap length between the first and second parts is 25 μm along the vertical direction, the Z-axis direction, or the construction direction of the target object. In some embodiments, the thickness of t1 is 30 μm and the thickness of t2 is 60 μm. In some embodiments, the thickness of t1 is 50 μm and the thickness of t2 is 75 μm. In some embodiments, the thickness of t1 is 50 μm and the thickness of t2 is 100 μm. In some embodiments, the thickness of t1 is 75 μm and the thickness of t2 is 150 μm.

[0094] Reference Figure 3D After the first layer of the third component has cured, the first layer of the third component and the material holding mechanism are separated. Then, the molding platform with the target object, the first layer of the second component, and the first layer of the third component adhered to it is moved to the area of ​​the material holding mechanism that carries material B. Material B is then radiation cured to form a second layer 342 on the first layer 341 of the second component 340, that is, to form the first part of the second layer in the second plurality of layers. The total thickness t3 of the first part composed of material B is greater than the total thickness t2 of the second part composed of material C, that is, t3 > t2. In some embodiments, at this time, the total thickness of the first part composed of the first material is equal to the sum of the first thickness and the second thickness, that is, t3 = t2 + t1.

[0095] Separate the second layer 342 of the cured second component from the material holding mechanism, and then move the molding platform or building platform 312 to the area where the material holding mechanism carries material C, as shown in the figure. Figure 3E Material C is radiation-cured to form a second layer 362 on the first layer 361 of the third component, i.e., forming a second portion of the second layer in a second plurality of layers, wherein the total thickness t4 of the second portion composed of material C is greater than the total thickness t3 of the first portion composed of material B, i.e., t4 > t3. In some embodiments, the total thickness of the second portion composed of the second material is twice the second thickness, i.e., t4 = t2 + t2. The steps of printing the second layer in a second plurality of layers described above are repeated, referring to... Figure 3FThis process is used to form a second or more layers of the target object, thereby enabling the printing of the target object.

[0096] The base material in the above embodiments may be the same as the first material, the same as the second material, or different from both the first and second materials. In some embodiments, the color of the first material is different from the color of the second material. In some embodiments, the base material includes at least one material or a mixture of multiple materials.

[0097] In some embodiments, refer to Figures 3A-3F The first multiple layers of the target object (the first component 320 of the target object) can be formed first, and then the second multiple layers of the target object (the second component 340 and the third component 360 of the target object) can be formed.

[0098] In some embodiments, refer to Figures 3A-3F The first portion (second component) of the second layer of the second plurality of layers of the target object is formed on the first portion of the first layer of the second plurality of layers along the vertical direction, the Z-axis direction, or the construction direction of the target object, and the first portion of the first layer and the second portion (third component) of the second layer of the second plurality of layers are spaced apart along a direction perpendicular to the vertical direction. For example, the second layer 342 of the second component is formed on the first layer 341 of the second component, and the first layer 341 is spaced apart from the second layer 362 of the third component.

[0099] In some embodiments, a first portion of the second layer of the target object is formed on a first portion of the first layer in a vertical direction, and in a plane perpendicular to the vertical direction, the first portion at least partially surrounds the second portion.

[0100] In some embodiments, refer to Figure 4 The second or more layers of the target object (the second component 440 and the third component 460 of the target object) can be formed first, and then the first or more layers of the target object (the first component 420 of the target object) can be formed.

[0101] Larger slice layer thicknesses are advantageous for accelerating the printing speed of the target object, while smaller slice layer thicknesses are beneficial for achieving better surface quality. Therefore, to better achieve the printing and manufacturing of the target object (ensuring both quality and efficiency), when forming the first part, a single material is used, which is easier to control. The slice layer thickness for this part of the target object can be set to be greater than the slice layer thickness for the second or more layers, thus improving printing speed and efficiency without affecting the printing effect. When printing the second or more layers, i.e., printing the second and third parts, which involves switching between two materials, the slice layer thickness for this part of the target object can be set to be less than the slice layer thickness for the first or more layers to ensure accuracy, thereby improving printing precision. For example, the slice layer thickness for the first or more layers can be set to 75μm, 100μm, 125μm, 150μm, etc., and the slice layer thickness for the second or more layers can be set to 25μm, 50μm, 75μm, 100μm, etc.

[0102] According to an embodiment of the present invention, a three-dimensional printing method is provided, comprising: moving a molding platform to a first material region, curing a first material to form a first portion of a three-dimensional object with a predetermined thickness, wherein the first portion has a first surface close to a molding surface of the molding platform and a second surface away from the molding surface, wherein the first surface is spaced apart from the molding surface by a first distance, and the second surface is spaced apart from the molding surface by a second distance; moving the molding platform from the first material region to a second material region, curing a second material to form a second portion of a three-dimensional object with a predetermined thickness, wherein the second portion has a third surface close to a molding surface of the molding platform and a fourth surface away from the molding surface, wherein the third surface is spaced apart from the molding surface by a third distance, and the fourth surface is spaced apart from the molding surface by a fourth distance; wherein the third distance is within the first distance and the second distance.

[0103] In some embodiments, the 3D printing method further includes: after forming a second portion of a preset thickness, moving a molding platform to a first material region and curing the first material of the preset thickness to form an additional first portion on the first portion, wherein the additional first portion has a fifth surface close to the molding surface and a sixth surface away from the molding surface, wherein the fifth surface is flush with the second surface, the fifth surface is spaced a fifth distance from the molding surface, the sixth surface is spaced a sixth distance from the molding surface, and wherein a fourth distance is within the fifth distance and the sixth distance.

[0104] This invention provides a photopolymerization 3D printing method, which includes the following steps.

[0105] Step S202: Solidify the first material with a first initial supplementary thickness in the first material region.

[0106] Step S204: A second material of a preset thickness is cured in the second material region. The preset thickness is greater than the first initial supplementary thickness.

[0107] Step S206: Cure the first material of a preset thickness in the first material region.

[0108] Step S208 involves alternately curing the second material and the first material to obtain the target cured portion. The target cured portion can be all parts of the three-dimensional object or only some parts.

[0109] Taking two curing materials as examples, Figure 5A This is a schematic diagram of the initial printing state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention, as shown below. Figure 5A As shown, the 3D printing equipment 500 includes a material holding mechanism (or material tray) 513. The material holding mechanism 513 holds two types of solidified materials. Material A is held in the material holding area 5131 (first material area), and material B is held in the material holding area 5132 (second material area). The forming platform 512 can move vertically and horizontally (ideally as follows). Figure 5A (As indicated by the arrow in the diagram). In some embodiments, a first material is cured in a first region 5131, and a second material is cured in a second region 5132 spaced apart from the first region.

[0110] The term "material holding mechanism" as used herein can be configured in a variety of ways. In some embodiments, a first region is defined by a container for holding a first material, a second region by a container for holding a second material, and the containers have at least a partially transparent bottom. In some embodiments, a first region is defined by a plate-like element for carrying the first material, a second region by a plate-like element for carrying the second material, and the plate-like element has a bottom material holding mechanism that is at least partially transparent. In some embodiments, multiple boxes are included, and liquid or paste-like materials are contained in the boxes. In some embodiments, a tray includes multiple plate-like elements on which liquid or paste-like materials are applied. In some embodiments, a tray includes at least one box and at least one plate-like element. In some embodiments, the first material is applied to the plate-like element for carrying the first material via a nozzle, and / or the second material is applied to the plate-like element for carrying the second material via a nozzle. The forming platform is sized to allow it to fall into the printing area of ​​the respective tray (e.g., box or plate-like element).

[0111] The terms “forming platform” and “tray” used herein should be understood as horizontal. In the event that a forming platform or tray is not horizontal due to manufacturing or layout errors, it also falls within the scope of protection of this application.

[0112] Figure 5A This is a schematic diagram of the initial printing state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention, wherein the forming platform is located above the material tray. Figure 5BThis is a schematic diagram of the first state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention, as shown below. Figure 5B As shown, the forming platform can be moved to the material holding area 5131 first, and then a printed portion with a thickness of h1 is cured. It can be understood that the cured portion with a thickness of h1 at this time represents the supplementary portion. The forming platform can be moved, the material tray can be moved, or both can be moved together, i.e., relative movement between the forming platform and the material tray. Preferably, the material holding mechanism and the forming platform move in the X or Y direction (in the horizontal plane of the material tray), and the forming platform also needs to move in the Z direction. The forming platform can rise directly a fixed distance, or it can undergo a single or multiple compound movements of rising first and then falling, ultimately making the lower surface of the printed part on the forming platform a fixed distance from the material holding area of ​​the material holding mechanism. Figure 5C This is a schematic diagram of the second state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention, as shown below. Figure 5C As shown, the cured portion of material 1 with a thickness of h1 is separated from the material tray. Figure 5D This is a schematic diagram of the third state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention, as shown below. Figure 5D As shown, the molding platform can be controlled to move above the material holding area 5132, and then material 2 with a thickness of h2 is cured, where h2 is greater than h1. It can be understood that the cured portion with a thickness of h2 at this time means that the distance between its upper surface and the molding surface of the molding platform is 0, and the distance between its lower surface and the molding surface of the molding platform is h2. In other embodiments, if a cured portion with a thickness of n slice layers t has already been cured, then the cured portion with a thickness of h2 at this time means that the distance between its upper surface and the molding surface of the molding platform is n*t, and the distance between its lower surface and the molding surface of the molding platform is n*t+h2. When curing material 2, the cured portion corresponding to material 1 is suspended relative to the material holding area, and will not cause compression or damage to the material holding area or the release film in the material holding area. Figure 5E This is a schematic diagram of the fourth state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention, as shown below. Figure 5E As shown, the cured portion of material 2 with a thickness of h2 obtained by curing can be controlled to separate from the material tray.

[0113] Figure 5FThis is a schematic diagram of the fifth state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention. The forming platform can be controlled to move above the material holding mechanism and at a distance h4 from the material holding area 5131, solidifying material 1 with a thickness of h3, where h4 = h1 + h3, and h4 > h2, h3 = h2. It is understood that the solidified portion with a thickness of h3 at this time indicates that the distance between its upper surface and the forming surface of the forming platform is h1, and the distance between its lower surface and the forming surface of the forming platform is h4 (h1 + h3). In other embodiments, if a solidified portion with a thickness of n slice layers t has already been solidified, then the solidified portion with a thickness of h3 at this time indicates that the distance between its upper surface and the forming surface of the forming platform is n*t + h1, and the distance between its lower surface and the forming surface of the forming platform is n*t + h4. When solidifying material 1 with a thickness of h3, the solidified portion composed of material 2 is suspended relative to area A, therefore, it will not cause compression (damage) to the material holding area (release film). Figure 5G This is a schematic diagram of the sixth state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention. The molding platform is controlled to rise so that the cured portion of material 1 with a thickness of h3 (or h4) is peeled off from the material tray. Similar operations can be repeated to print slice models. The thickness of each curing can be a preset thickness, that is, each print can be a thickness of h3.

[0114] Similarly, taking two curing materials as examples, Figure 6A This is a schematic diagram of the first state of the photopolymerization 3D printing method provided according to some embodiments of the present invention, such as... Figure 6A As shown, material M is contained in material holding area 6131, and material N is contained in material holding area 6132. At this time, the distance between the molding platform and material holding area 6131 can be controlled to be h1 to photocur a slice model with a thickness of h1. Figure 6B This is a schematic diagram of the second state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention, as shown below. Figure 6B As shown, the molding platform can be controlled to move up to a position h2 away from the material tray above the material holding area 6131, where h2 is greater than h1 and h2 can be a preset thickness. Then it is moved horizontally above the material holding area 6132. At this time, the distance between the cured part obtained by photocuring and the material holding area 6132 is δh1, where δh1 > 0, so it will not cause compression to the material holding area 6132. Figure 6C This is a schematic diagram of the third state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention, as shown below. Figure 6CAs shown, the molding platform can be moved so that the distance between it and the material tray is h4, where h4 = h3 + h1, and h3 can be equal to h2 (preset thickness). At this time, the distance between the cured slice of material N and the material tray is also h1, which will not cause compression to the material holding area 6131. ​​Repeat the above steps and perform photopolymerization printing according to the printing data to obtain the final target model.

[0115] In some embodiments, the absolute value of the difference between h2 and h1 is 1%-99% of the preset thickness, preferably 2%-90%, more preferably 5%-80%, for example 30%, 40%, 50%, 60% or 70%. For example, if the preset thickness is 50 μm, the absolute value of the difference between h2 and h1 can be 1 μm, 2 μm, 5 μm, 10 μm, 20 μm, 25 μm, 30 μm, 40 μm, 48 μm or 49 μm.

[0116] In some embodiments, moving the molding platform from a first material region to a second material region includes: driving the molding platform to rise a first height in a direction away from the first material region; driving the molding platform horizontally above the second material region; and driving the molding platform to descend a second height in a direction closer to the second material region. For example, when the first or second material region has vertically extending sidewalls, the first height is greater than the height of the sidewalls to allow the molding platform to switch smoothly between the first and second material regions. For example, the first height can be 2-20 times the height of the sidewalls. When both the first and second material regions are plate-shaped elements, the first height is greater than a preset thickness to allow the cured portion to separate from the tray (first or second material region).

[0117] Figure 7A This is a schematic diagram of the fourth state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention, as shown below. Figure 7A As shown, the dashed line between the material holding area 7131 and the material holding area 7132 can be a solid structure, such as a partition, that separates the two material holding areas at a certain height. The molding platform can be controlled to move up to a predetermined height (e.g., L1+h1) above the material holding area 7131, and then move horizontally above the material holding area 7132. At this time, the distance between the material holding area 7131 and the lower surface of the slice portion corresponding to the photocured material M on the molding platform is L1.

[0118] Figure 7B This is a schematic diagram of the fifth state of the photopolymerization 3D printing method provided by an optional embodiment of the present invention, as shown below. Figure 7BAs shown, the forming platform can be controlled to descend to a position where the distance from the material receiving area 7132 is h_layer, and then the corresponding sliced part of material N with a thickness of h_layer is obtained by light curing. At this time, the descending distance of the forming platform is L2, and after the descent, the distance between the lower surface of the light-cured sliced part corresponding to material M and the material receiving area 7132 is δh1. Figure 7C is a schematic diagram of the sixth state of the light-curing 3D printing method provided according to an optional embodiment of the present invention. As Figure 7C shown, after controlling the forming platform to move upward and then translate above the material receiving area 7131, where the distance between the lower surface of the light-cured sliced part corresponding to material N and the material receiving area 7131 is L3. Figure 7D is a schematic diagram of the seventh state of the light-curing 3D printing method provided according to an optional embodiment of the present invention. As Figure 7D shown, the forming platform can be controlled to descend by L4. At this time, the height between the light-cured sliced part corresponding to material M on the forming platform and the material receiving area can be controlled to be h_layer, and the distance between the lower surface of the sliced part corresponding to material N and the material receiving area 7131 is δh2. At this time, the sliced part corresponding to material M with a thickness of h_layer is obtained by light curing, that is, the total thickness of the formed material M is h_layer + h1. The above operations can be repeated to obtain a multi-layer sliced model, and finally the target model can be obtained.

[0119] As an example, L1 = 10mm, the material tray and the platform can move relatively, so that the platform faces the B material tray, that is, return to the B printing area, and then the platform descends by L2 = 9.975mm (10mm - 9.975mm = 25μm). Among them, L1 - L2 = δh1. The advantages of this movement method include avoiding the solid structure with a certain height between the A material tray and the B material tray, such as the side wall of the box-shaped material tray, or when the heights of the A and B materials applied are different, avoiding direct horizontal sliding to cause material mixing. The forming platform can also perform composite movements such as rising and descending multiple times to achieve the final displacement of δh1. Among them, L1 is any value in [δh1, 100000mm]. Then, expose the N material in the B material tray area to partially cure the N material. Then, the forming platform can rise by L3, for example, L3 = 10mm, the material tray platform moves relatively, so that the platform faces the A material tray, that is, return to the A printing area, and then the platform descends by L4 = 9.975mm (10mm - 9.975mm = 25μm). L3 - L4 = δh2, where 0 < δh1 < h_layer, 0 < δh2 < h_layer, and δh1 + δh2 = h_layer.

[0120] In some embodiments, δh1 = δh2 = h_layer / 2, which is half of the preset layer thickness. Other allocation ratios are also possible, such as 40%+60% or 30%+70%. Here, h_layer, i.e., the layer thickness, is selected from 2 to 500 μm. Preferably, it is 5 to 200 μm, or 10 to 150 μm, or 20 to 100 μm, or 25 to 50 μm. Other examples include 2 μm, 3 μm, and 4 μm.

[0121] In some embodiments, the 3D printing method further includes: alternating curing to form n first portions (i.e., the total thickness of the target cured portions is n*h2) and n second portions (i.e., the total thickness of the target cured portions is n*h3), where n≥2, or alternating curing to form n first portions and n-1 second portions, where n≥2. The final material cured in an alternating manner can be either a first material or a second material.

[0122] In some embodiments, the 3D printing method further includes: after forming n first portions (i.e., the total thickness of the target solidified portions is n*h2) and n second portions (i.e., the total thickness of the target solidified portions is n*h3), moving a molding platform to a first material region and solidifying the first material of a second supplementary thickness to form an end supplementary portion. The end supplementary portion has a first end supplementary surface near the molding surface of the molding platform and a second end supplementary surface away from the molding surface, wherein the first end supplementary surface is spaced from the molding surface by a first end supplementary distance, and the second end supplementary surface is spaced from the molding surface by a second end supplementary distance; wherein the first end supplementary surface is flush with the last formed surface of the nth first portion, and the second end supplementary surface is flush with the last formed surface of the nth second portion. It is understood that this end supplementary portion is not mandatory, especially when the most recently solidified portion is the final slice of the model.

[0123] In some embodiments, the 3D printing method further includes: after forming n first portions (i.e., the total thickness of the target solidified portions is n*h2) and n-1 second portions (i.e., the total thickness of the target solidified portions is (n-1)*h3), moving the molding platform to a second material region and solidifying the second material of a second supplementary thickness to form an end supplementary portion. The end supplementary portion has a first end supplementary surface near the molding surface of the molding platform and a second end supplementary surface away from the molding surface, wherein the first end supplementary surface is spaced from the molding surface by a first end supplementary distance, and the second end supplementary surface is spaced from the molding surface by a second end supplementary distance; wherein the first end supplementary surface is flush with the last formed surface of the (n-1)th second portion, and the second end supplementary surface is flush with the last formed surface of the nth first portion. It is understood that this end supplementary portion is not necessary, especially when the most recently solidified portion is the last slice of the model.

[0124] Understandably, when obtaining slices from a 3D object's data model, slicing can be performed according to actual needs. Slicing can include an initial slice layer, multiple intermediate slice layers, and an end slice layer. For example, if a 3D object's data model has 500 slice layers, each 50 μm thick, conventional layer-by-layer curing can be used for layers 1 to 100, such as curing the first material at a relatively fast speed, with each curing thickness being 50 μm. Then, for layers 101 to 300, the aforementioned non-flush curing or alternating curing can be used, for example, first curing a 50 μm thick second material, then curing a 100 μm thick first material, followed by curing a 100 μm thick second material, then curing a 100 μm thick first material, and so on, to complete the non-flush or alternating curing of layers 101 to 300. Conventional layer-by-layer curing can be used again for layers 301 to 500. The layer thickness of the slices and the preset thickness in the alternating curing can be designed.

[0125] The initial supplementary portion belongs to the initial slice layer or the first slice layer of the 3D object's data model, which means that non-flush curing or alternating curing begins directly. The initial supplementary portion belongs to the intermediate slice layer of the 3D object's data model, which means that non-flush curing or alternating curing begins only after multiple layers have been formed through conventional layer-by-layer curing.

[0126] In some embodiments, the first or second material is cured in a single-cure slice thickness manner before the initial supplementary portion is formed.

[0127] In some embodiments, an end supplement portion is formed when printing is performed on the end slice layer or at least one of a plurality of intermediate slice layers.

[0128] In some embodiments, after the end supplement portion is formed, the first material or the second material is cured in a single-cure slice thickness manner.

[0129] In some embodiments, the first portion and the second portion are spaced apart in a plane parallel to the molding surface. The first portion and the second portion may be adjacent or spaced apart during construction. In the same slice layer or two adjacent slice layers, there may be at least one first portion and at least one second portion, for example, three first portions and four second portions. Multiple first portions made of the same material may be cured simultaneously.

[0130] In some embodiments, the first portion surrounds the second portion in a plane parallel to the molding surface. For example, a first material with high surface quality for coloring forms the outer first portion, while a second material with better mechanical properties forms the inner second portion.

[0131] In some embodiments, the 3D printing method further includes providing at least a first printing region, a second printing region, and a third printing region, wherein the material applied in the third printing region is the same as or different from at least one of the first and second materials.

[0132] This application also provides a 3D printing method, comprising: curing a first material with a first initial supplementary thickness in a first material region, and curing a second material with a preset thickness in a second material region; after curing the second material with the preset thickness, curing the first material with the preset thickness in the first material region, wherein the first initial supplementary thickness is less than the preset thickness. The statement "curing at least the first initial supplementary thickness of the first material" refers to: a) curing only the material with the first initial supplementary thickness; or b) curing a first material with a thickness greater than the first initial supplementary thickness. In one example, when the first initial supplementary thickness is 20 μm, the slice thickness is 50 μm, and the preset thickness is 100 μm, the first material of 20 μm can be cured first in the first material region, or the first material of 70 μm (20 μm + 50 μm) can be cured first in the first material region, or the first material of 120 μm (20 μm + 50 μm + 50 μm) can be cured first in the first material region; then a non-flush curing step is performed, for example, curing the second material of the preset thickness (100 μm) in the second material region. In another example, when the first initial supplemental thickness is 20 μm, the slice thickness is 50 μm, and the preset thickness is 50 μm, the first material of 20 μm can be cured first in the first material region, or the first material of 70 μm (20 μm + 50 μm) can be cured first in the first material region, or the first material of 120 μm (20 μm + 50 μm + 50 μm) can be cured first in the first material region; then a non-flush curing step is performed, for example, curing the second material of the preset thickness (50 μm) in the second material region.

[0133] In some embodiments, non-flush curing or alternating curing can be applied to three different materials. For example, a 3D printing device includes a first material region, a second material region, and a third material region. It can first cure a first initial supplementary thickness of 20 μm in the first material region, then cure a second initial supplementary thickness of 40 μm in the second material region, then cure a preset thickness of 60 μm in the third material region, then cure a preset thickness of 60 μm in the first material region, then cure a preset thickness of 60 μm in the second material region, then cure a preset thickness of 60 μm in the third material region, and so on. The target cured portion is formed in this non-flush curing or alternating curing manner.

[0134] In some embodiments, non-flush curing or alternating curing can be applied to at least four materials. For example, a 3D printing device includes a first material region, a second material region, ..., an nth material region, where n ≥ 4. A first initial supplementary thickness of 20 μm can be cured first in the first material region, then a second initial supplementary thickness of 40 μm can be cured in the second material region, ..., then a predetermined thickness of the nth material region can be cured, then a predetermined thickness of the first material region can be cured, then a predetermined thickness of the second material region can be cured, ..., then a predetermined thickness of the nth material region can be cured... The target cured portion is formed in this non-flush curing or alternating curing manner. It is understood that the specific values ​​can be selected.

[0135] In some embodiments, the first initial supplementary thickness is not less than the second initial supplementary thickness, the second initial supplementary thickness is not less than the third initial supplementary thickness, ..., the (n-2)th initial supplementary thickness is not less than the (n-1)th initial supplementary thickness.

[0136] As an alternative embodiment, multiple curing materials are located in multiple trays or in multiple areas of a single tray.

[0137] Optionally, multiple curing materials can be located in multiple trays or in multiple areas of a single tray. For example, the tray may be a glass and film without edges or intermediate gaps, appearing as a single tray but divided into areas A and B; or it may consist of two trays, A and B.

[0138] As an optional embodiment, multiple curing materials are controlled to be cured sequentially based on the first-layer slice model to obtain slice models other than the first-layer slice model in the multi-layer slice model, including: controlling multiple curing materials to be cured sequentially on the first-layer slice model on the molding platform to obtain multiple slice parts, wherein the thickness of each of the multiple slice parts is a preset thickness; and obtaining slice models other than the first-layer slice model in the multi-layer slice model based on the multiple slice parts.

[0139] Optionally, when solidifying the slice model (excluding the first layer slice model), the thickness of each slice can be controlled to be the same, based on the first layer slice model, and all slices can have a preset thickness, namely h_layer. The value of h_layer can be adjusted according to the actual situation. However, when printing the last layer slice model, the required printing thickness can be adjusted according to the actual situation to form the target model.

[0140] In some embodiments, a first material is applied to a first material region before curing, such that the thickness of the first material is 1-10 times a preset thickness; and / or a second material is applied to a second material region before curing, such that the thickness of the second material is 1-10 times a preset thickness. When the applied material is a liquid or paste, a lower liquid level is beneficial for material curing, and is particularly beneficial for multi-color printing, because the forming platform or printhead will not be immersed too deeply in the material, thereby reducing the possibility of color mixing between multiple colors.

[0141] In some embodiments, the thickness of the first material is 2-4 times the preset thickness.

[0142] As an optional embodiment, the thickness of the various curing materials in their respective trays does not exceed a preset thickness.

[0143] Optionally, the thickness of various curing materials in their respective trays should not exceed a preset thickness. Excessive material thickness in the trays may cause excess material to adhere to the slice model and the forming platform, affecting the final result of the target model. During photopolymer printing, after printing a slice, the resulting slice can be cleaned. The cleaning method can be determined based on the actual situation. For example, the forming platform can be rotated centrifugally to remove residual material from the previous print, or residual material can be dried using air nozzles, or the material can be absorbed by a sponge. Whether cleaning is necessary can also be determined based on the degree of material penetration.

[0144] As an optional embodiment, the above-described 3D printing method further includes: cleaning the target object after curing the first material to form a first portion of a second layer of a second plurality of layers on a first portion of the first layer, and / or

[0145] The target object is cleaned by curing a second material to form a second portion of a second plurality of layers on a second portion of a first layer.

[0146] In some embodiments, the 3D printing method further includes moving the molding platform to a cleaning area before moving the molding platform from a first material region to a second material region or from a second material region to a first material region, to clean the 3D object being molded on the molding platform. This cleaning step helps to avoid mixing between the first and second materials.

[0147] In some embodiments, the 3D printing method further includes cleaning after forming at least two first parts or at least two second parts. The frequency of cleaning can be controlled, for example, cleaning is performed after curing five slice layers.

[0148] In some embodiments, cleaning includes at least one of rotating a forming platform, wiping a three-dimensional object, applying airflow to a three-dimensional object, and surrounding the target object with an adsorbent to remove excess printing material.

[0149] In some embodiments, cleaning includes at least one of a rotational forming platform, wiping the three-dimensional object, applying airflow to the three-dimensional object, and surrounding the three-dimensional object with an absorbent to remove excess printed material. For example, a rotational forming platform is used to shake off material adhering to a cured portion. For example, an absorbent, such as a sponge, is used to contact the cured portion to absorb material thereon.

[0150] In some embodiments, the 3D printing method further includes: cleaning excess material in the first material region during or after moving the molding platform from the first material region to the second material region; and / or, cleaning excess material in the second material region during or after moving the molding platform from the second material region to the first material region.

[0151] In some embodiments, the 3D printing method further includes cleaning excess material in the first material region using a scraper.

[0152] In some embodiments, the first material in the first material region is different from the second material in the second material region. The properties of the first material and the second material may differ; for example, the first material may have a higher viscosity, while the second material may have a lower viscosity.

[0153] In some embodiments, the color of the first material is different from the color of the second material. This allows materials of different colors to be cured in the same slice layer or multiple adjacent slice layers.

[0154] In some embodiments, the first material is a mixture or composite material. Alternatively, it may comprise multiple materials or a mixture of multiple materials. For example, a printing material composed of at least one of cyan, magenta, yellow, and black (CMYK). For example, the first material may include cyan and yellow materials. For example, the first material may include a mixture of cyan and yellow materials.

[0155] In some embodiments, the first material is an additive. For example, the additive includes at least one of the following: pigment, dye, defoamer, leveling agent, wetting agent, dispersant, matting agent.

[0156] In some embodiments, the first material and / or the second material are liquid photocurable materials arranged in a tray of a 3D printing device.

[0157] In some embodiments, the first material and / or the second material are applied to the material region via a nozzle. For example, materials within a predetermined viscosity range are applied via the nozzle. The predetermined viscosity threshold corresponding to the available viscosity printing materials at room temperature (e.g., 10–40°C, preferably 20–30°C, e.g., 25°C) is between 50 centipoise and 500,000 centipoise, preferably between 500 centipoise and 200,000 centipoise, more preferably between 100 and 500 centipoise, and particularly preferably between 200 and 300 centipoise.

[0158] Slicing the 3D data model is beneficial in the pre-processing stage of 3D printing. The 3D data model can be sliced ​​into multiple slices of the same or different thicknesses. For example, a single 3D data model can be sliced ​​into 1000 layers, where the slices from layers 1 to 500 have a layer thickness of 50 μm, and the slices from layers 501 to 1000 have a layer thickness of 150 μm.

[0159] In some embodiments, the design of the slice layer thickness during preprocessing is related to a preset layer thickness in non-flush printing or alternating printing. For example, the slice layer thickness is proportional to the preset layer thickness. For example, the ratio of the slice layer thickness to the preset layer thickness is 0.5, 1, or 2. In an exemplary example, the slice layer thickness is 60 μm, and the preset layer thickness is 30 μm, 60 μm, or 120 μm.

[0160] In some embodiments, the slice layer thickness during preprocessing is designed independently of the preset layer thickness in non-flush printing or alternating printing.

[0161] In some embodiments, the above-described 3D printing method includes providing at least a third region, wherein the material applied in the third region is the same as or different from at least one of the first material and the second material.

[0162] Figure 8 A 3D printing device (or system) involving three materials is shown. Figure 8 The printing apparatus 900 includes a material receiving mechanism (or tray) comprising a first material region 9131 for material A, a second material region 9132 for material B, and a third material region 9133 for material C. The printing apparatus also includes a forming platform or building device 912, on which the initially cured portion will adhere.

[0163] Figure 8 An embodiment for forming a target object comprising three different materials is shown. Figure 8In the illustrated embodiment, the additive manufacturing apparatus 9 includes a support device 9131 for supporting material A, a support device 9132 for supporting material B, and a support device 9133 for supporting material C. The target object includes a single-material portion Bp obtained by continuously curing material B according to the slice layer thickness, and also includes multiple layers involving the three materials A, B, and C. Target layers A1, A2, A3, B1, B2, B3, C1, C2, and C3 have the same thickness (preset thickness). The thickness of supplementary portion A0 is less than the thickness of supplementary portion B0, and the thickness of supplementary portion B0 is less than the preset thickness. In one example, the thickness of supplementary portion A0 is 20 μm, the thickness of supplementary portion B0 is 40 μm, the preset thickness is 60 μm, and the slice layer thickness is 20 μm. In another example, the thickness of supplementary portion A0 is 20 μm, the thickness of supplementary portion B0 is 30 μm, the preset thickness is 50 μm, and the slice layer thickness is, for example, 10 μm.

[0164] It is understood that there is a horizontal difference between two adjacent target layers composed of different materials (here, "different materials" refers to materials from different material regions, not necessarily materials with different physical and / or chemical properties). The term "horizontal difference" can be interpreted as the height difference between the lower surfaces of the two adjacent target layers, or the height difference between the upper surfaces of the two adjacent target layers, or the height difference between the virtual mid-surfaces of the two adjacent target layers, or similarly.

[0165] In one example, if the thickness of the first supplementary part A0 is set to 20 μm, the thickness of the second supplementary part B0 is 35 μm, and the preset thickness is 60 μm, then: the horizontal difference between the first target layer A1 composed of material A and the first target layer B1 composed of material B is 15 μm; the horizontal difference between the first target layer B1 composed of material B and the first target layer C1 composed of material C is 35 μm.

[0166] In another example, if the thickness of the first supplementary part A0 is set to 20 μm, the thickness of the second supplementary part B0 is 30 μm, and the preset thickness is 50 μm, then: the horizontal difference between the first target layer A1 made of material A and the first target layer B1 made of material B is 10 μm; the horizontal difference between the first target layer B1 made of material B and the first target layer C1 made of material C is 30 μm.

[0167] In one example, if the thickness of the first supplementary part A0 is set to 20 μm, the thickness of the second supplementary part B0 is 35 μm, and the preset thickness is 60 μm, then: the horizontal difference between the first target layer A1 composed of material A and the first target layer B1 composed of material B is 15 μm; the horizontal difference between the first target layer B1 composed of material B and the first target layer C1 composed of material C is 35 μm.

[0168] In another example, if the thickness of the first supplementary part A0 is set to 20 μm, the thickness of the second supplementary part B0 is 30 μm, and the preset thickness is 50 μm, then: the horizontal difference between the first target layer A1 made of material A and the first target layer B1 made of material B is 10 μm; the horizontal difference between the first target layer B1 made of material B and the first target layer C1 made of material C is 30 μm.

[0169] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0170] This application also provides a 3D printing apparatus, comprising: a material holding mechanism and a forming platform, configured to: move to a first material region to allow first materials B and N to be cured to form a first portion of a 3D object with a preset thickness, wherein the first portion has a first surface close to the forming surface of the forming platform and a second surface away from the forming surface, wherein the first surface is spaced apart from the forming surface by a first distance, and the second surface is spaced apart from the forming surface by a second distance; and move to a second material region to allow second materials A and M to be cured to form a second portion of a 3D object with a preset thickness, wherein the second portion has a third surface close to the forming surface of the forming platform and a fourth surface away from the forming surface, wherein the third surface is spaced apart from the forming surface by a third distance, and the fourth surface is spaced apart from the forming surface by a fourth distance; wherein the third distance is within the first distance and the second distance.

[0171] According to an embodiment of the present invention, a photopolymerization 3D printing apparatus for implementing the above-described photopolymerization 3D printing method is also provided, which is applied to the manufacture of a three-dimensional target object. The target object includes a first plurality of layers (1~m, m≥2) and a second plurality of layers (1~n, n≥3), wherein the second plurality of layers include at least two materials. The three-dimensional printing apparatus includes:

[0172] Material holding mechanism;

[0173] A molding platform configured to adhere three-dimensional target objects;

[0174] Radiation device for radiating light onto the material holding mechanism; and

[0175] A drive mechanism, wherein the drive mechanism is configured to move at least one of a molding platform and a material holding mechanism;

[0176] The 3D printing equipment is configured as follows:

[0177] (a) By driving the base material areas of the molding platform and the material holding mechanism, the base material is aligned and solidified by the radiation device to form the first multiple layers of the target object on the molding platform;

[0178] (b) By means of a drive mechanism, the first material area of ​​the forming platform and the material holding mechanism are aligned, and the first material is cured by means of a radiation device to form a first portion of the first layer of a second plurality of layers, the first portion of the first layer having a first thickness;

[0179] (c) By driving the second material region of the molding platform and the material holding mechanism, the second material is aligned and cured by the radiation device to form a second part of the first layer in a second plurality of layers, the second part of the first layer having a second thickness greater than the first thickness, wherein the first material and the second material are different;

[0180] (d) By driving the first material area of ​​the molding platform and the material holding mechanism, the first material is aligned and cured by the radiation device to form the first part of the second layer of the second plurality of layers on the first part of the first layer, wherein the total thickness of the first part composed of the first material is greater than the total thickness of the second part composed of the second material.

[0181] (e) By driving the second material area of ​​the molding platform and the material holding mechanism, the second material is aligned and cured by the radiation device to form the second part of the second layer of the second plurality of layers on the second part of the first layer, wherein the total thickness of the second part composed of the second material is greater than the total thickness of the first part composed of the first material.

[0182] Repeat steps (b)-(e) to form a second or more layers of the target object.

[0183] In certain embodiments of the present invention, a 3D printing method is provided. This method involves acquiring printing data of a target model, including data corresponding to each of the multiple slice models corresponding to the target model; based on the data corresponding to the first-layer slice model in the printing data, controlling multiple curing materials to sequentially cure multiple first-layer slice portions on a molding platform to obtain a first-layer slice model, wherein each first-layer slice portion corresponds one-to-one with a different curing material, and the thickness of each first-layer slice portion increases sequentially according to the curing order but does not exceed a preset thickness; sequentially, based on the data in the printing data excluding the data corresponding to the first-layer slice model, controlling multiple curing materials to sequentially cure based on the first-layer slice model according to the curing order to obtain slice models other than the first-layer slice model in the multi-layer slice model; and obtaining the target model based on the multi-layer slice model. This method achieves the technical effect of extending the life of the material tray by creating a height difference in the first layer to avoid contact between part of the model and the material tray.

[0184] like Figure 9 As shown, Figure 9 A 3D printing apparatus 900 is shown. A first component 920 of a target object is adhered to a forming platform or build platform 912 of the 3D printing apparatus 900. This first component is formed of a base material D. A second component 940 and a third component 960 are formed on the first component 920 along the vertical direction, the Z-axis direction, or the build direction of the target object, wherein the second component 940 is made of material A, and the third component 960 is made of a different material B. A fourth component 980 is formed on the second component 940 and the third component 960 along the vertical direction, the Z-axis direction, or the build direction of the target object, wherein the fourth component 980 is made of the base material D. Figure 9 It shows how to build an object first using a single material, then using two materials, and finally using a single material.

[0185] Figure 10A A schematic diagram of forming an object according to some embodiments is shown. For example... Figure 10AAs shown, the additive manufacturing system 1000 is used to manufacture an object comprising a first part 1020 made of material A and second and third parts (of equal height) adhered to the first part 1020. The second part comprises multiple layers 1041, 1042, ..., 1045, 1046 made of material B. The third part comprises multiple layers 1061, 1062, ..., 1064, 1065 made of material C. The first layer 1041 of the second part has a thickness of 50 μm, the last layer 1046 of the second part has a thickness of 50 μm, and the intermediate layers 1042, ..., 1045 of the second part have a thickness of 100 μm. All layers 1061, 1062, ..., 1064, 1065 of the third part have a thickness of 100 μm. The formation of the second and third parts is performed in the following order: forming the first layer 1041 of the second part; forming the first layer 1061 of the third part; forming the second layer 1042 of the second part; forming the second layer 1062 of the third part; ... ...; forming the penultimate layer 1045 of the second part; forming the last layer 1065 of the third part; forming the last layer 1046 of the second part. This results in the second part having a non-uniform layer thickness overall, while the third part has a uniform layer thickness overall. When the second part of the object is easily noticeable (e.g., the object is a dental model worn on a patient, the second part being the gingival portion and the third part being the crown portion), the surface of the formed second part has a distinct boundary line due to the layer thickness variation (from 50 μm to 100 μm), while the surface of the formed third part does not have a distinct boundary line due to the layer thickness variation (always 100 μm). When the thickness of the first part 1020 composed of material A is 100 μm, the surface of the second part formed has a clear boundary line due to the change in layer thickness (100 μm changes to 50 μm, 50 μm changes to 100 μm), while the surface of the third part formed does not have a clear boundary line due to the change in layer thickness (always 100 μm).

[0186] Those skilled in the art will understand that, because the curing shrinkage rate remains constant, changes in layer thickness will lead to changes in the amount of shrinkage, which may result in a distinct dividing line during actual printing. It features a gingiva composed of pink material and a crown composed of white material, with the crown embedded in the gingiva. Figure 10B A clear boundary line is shown on the outer surface of the gingiva, the height of which corresponds to the height of the contact point between the lowest point of the crown and the gingiva. (In construction) Figure 10B When constructing the gingiva as shown, a single layer with a thickness of 50 μm is built at the height of the dividing line, and multiple layers with a thickness of 100 μm are built in the remaining parts (above and below the height of the dividing line). Figure 10BWhen constructing the crown, multiple layers were consistently built with a thickness of 100 μm. This resulted in layers with abrupt thickness changes (i.e., layers with a thickness of 50 μm) within the multiple layers of the gingiva. After fabrication, the boundary line on the outer surface of the gingiva is easily identifiable to the human eye, while the boundary line on the inner surface (i.e., the surface of the gingiva that contacts the crown) is not easily identifiable to the human eye.

[0187] In some embodiments, constructed in other ways Figure 10B The tooth model is shown in the diagram. When constructing the crown of the tooth model, a single layer with a thickness of 50 μm was built at the height of the lowest point of the crown where it contacts the gingiva, and multiple layers with a thickness of 100 μm were built in the remaining areas (above and below this height). When constructing the gingiva of the tooth model, multiple layers with a thickness of 100 μm were consistently built. This results in layers with abrupt thickness changes (i.e., layers with a thickness of 50 μm) within the crown layers, while no such abrupt thickness changes exist within the gingiva layers. After fabrication, the tooth model has no boundary line on the gingival surface, and the boundary line on the crown surface (at the height of the lowest point of the crown where it contacts the gingiva) is obscured by the gingiva and is not easily visible to the human eye.

[0188] Figure 10C A schematic diagram of forming an object according to some embodiments is shown. For example... Figure 10CAs shown, the additive manufacturing system 1000 is used to manufacture an object comprising a first portion 1020 made of material A and second and third portions adhered to the first portion 1020 (the second and third portions are of equal height, and the second portion is at least partially surrounded by the third portion). The second portion comprises multiple layers 1041, 1042, ..., 1045, 1046 made of material B. The third portion comprises multiple layers 1061, 1062, ..., 1064, 1065 made of material C. The first layer 1041 of the second portion has a thickness of 50 μm, the last layer 1046 of the second portion has a thickness of 50 μm, and the intermediate layers 1042, ..., 1045 of the second portion have a thickness of 100 μm. All layers 1061, 1062, ..., 1064, 1065 of the third portion have a thickness of 100 μm. The second and third parts are formed in the following order: forming the first layer 1041 of the second part; forming the first layer 1061 of the third part; forming the second layer 1042 of the second part; forming the second layer 1062 of the third part; ... ...; forming the penultimate layer 1045 of the second part; forming the last layer 1065 of the third part; forming the last layer 1046 of the second part. This results in the second part having a non-uniform layer thickness, while the third part has a uniform layer thickness. The surface of the formed second part has a distinct boundary line due to the layer thickness variation (from 50 μm to 100 μm), while the surface of the formed third part does not have a distinct boundary line due to the layer thickness variation (always 100 μm). Since the second part is at least partially surrounded by the third part, the boundary line on the second part is obscured by the third part and is not easily perceptible to the human eye.

[0189] Figure 11 A schematic diagram of forming an object according to some embodiments is shown. For example... Figure 11As shown, the additive manufacturing system 1100 is used to manufacture an object comprising a first portion 1120 made of material A, a second portion and a third portion (of equal height) adhered to the first portion 1120, and a support portion 1110. The second portion, connected to the support portion 1110 and the first portion 1120, comprises multiple layers 1141, 1142, ..., 1145, 1146 made of material B. The third portion, connected to the first portion 1120, comprises multiple layers 1061, 1062, ..., 1064, 1065 made of material C. The first layer 1141 of the second portion has a thickness of 50 μm, the last layer 1146 of the second portion has a thickness of 50 μm, and the intermediate layers 1142, ..., 1145 of the second portion have a thickness of 100 μm. All layers 1161, 1162, ..., 1164, 1165 of the third portion have a thickness of 100 μm. The second and third parts are formed in the following order: forming the first layer 1141 of the second part; forming the first layer 1161 of the third part; forming the second layer 1142 of the second part; forming the second layer 1162 of the third part; ... ...; forming the penultimate layer 1145 of the second part; forming the last layer 1165 of the third part; forming the last layer 1146 of the second part. This results in the second part having a non-uniform layer thickness overall, while the third part has a uniform layer thickness overall. The surface of the formed second part has a boundary line due to the layer thickness variation (from 50 μm to 100 μm), while the surface of the formed third part does not have a boundary line due to the layer thickness variation (always 100 μm). The boundary line of the second part exists in the initial and final layers used to form the second part, compared to (see reference) the initial and final layers of the second part. Figure 10B (As shown), it is not easily noticed by the human eye.

[0190] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0191] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0192] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A three-dimensional printing method for manufacturing a target object, the target object comprising a first plurality of layers and a second plurality of layers, characterized in that, include: Provide a 3D printing device, the 3D printing device comprising: The material holding mechanism is configured to support the material. A forming platform is located above the material holding mechanism and configured to adhere the target object; The target object is formed using a base material, creating the first multiple layers (1~m, m≥2); and The target object is formed using a first material and a second material different from the first material, comprising a second plurality of layers (1 to n, n ≥ 3) including: (a) Curing a first material to form a first portion of a first layer of a second plurality of layers on the molding platform, the first portion of the first layer having a first thickness; (b) Control the molding platform to rise so as to separate the first portion of the first layer from the material holding mechanism; (c) Controlling the lower surface of the first portion of the first layer to form a first distance from the material holding mechanism, and curing the second material to form a second portion of the first layer in a second plurality of layers on the molding platform, the second portion of the first layer having a second thickness greater than the first thickness; (d) Control the molding platform to rise so as to separate the second portion of the first layer from the material holding mechanism; (e) Controlling the lower surface of the second portion of the first layer to form a second distance with the material holding mechanism, and curing the first material to form the first portion of the second layer of a second plurality of layers on the first portion of the first layer, wherein the total thickness of the first portion composed of the first material is greater than the total thickness of the second portion composed of the second material; (f) Control the molding platform to rise so as to separate the first portion of the second layer from the material holding mechanism; (g) Controlling the lower surface of the first portion of the second layer to form a third distance with the material holding mechanism, and curing the second material to form the second portion of the second layer of the second plurality of layers on the second portion of the first layer, wherein the total thickness of the second portion composed of the second material is greater than the total thickness of the first portion composed of the first material; (h) Repeat steps (d) and (g) to form a second or more layers of the target object.

2. The three-dimensional printing method according to claim 1, characterized in that, include: - Before the first plurality of layers are formed, the second plurality of layers are formed; or - The first multiple layers are formed before the second multiple layers are formed.

3. The three-dimensional printing method according to claim 1, characterized in that, The first thickness is 1%-99% of the second thickness.

4. The three-dimensional printing method according to claim 1, characterized in that, The first thickness is 30% to 70% of the second thickness.

5. The three-dimensional printing method according to claim 1, characterized in that, The first thickness is 40% to 60% of the second thickness.

6. The three-dimensional printing method according to claim 1, characterized in that, The first thickness is 50% of the second thickness.

7. The three-dimensional printing method according to claim 1, characterized in that, The second thickness is 5~300μm.

8. The three-dimensional printing method according to claim 1, characterized in that, The second thickness is 20~200μm.

9. The three-dimensional printing method according to claim 1, characterized in that, The second thickness is 50~150μm.

10. The three-dimensional printing method according to claim 1, characterized in that, The second thickness is 60~120μm.

11. The three-dimensional printing method according to claim 1, characterized in that, in, The basic material: - Same as the first material, or - Same as the second material, or - Different from the first material and the second material.

12. The three-dimensional printing method according to claim 1, characterized in that, The color of the first material is different from the color of the second material.

13. The three-dimensional printing method according to claim 1, characterized in that, The base material includes at least one material or a mixture of multiple materials.

14. The three-dimensional printing method according to claim 1, characterized in that, In step (e), the total thickness of the first portion formed by the first material is equal to the sum of the first thickness and the second thickness.

15. The three-dimensional printing method according to claim 14, characterized in that, In step (g), the total thickness of the second portion made of the second material is twice the second thickness.

16. The three-dimensional printing method according to claim 1, characterized in that, The first portion of the second layer is formed on the first portion of the first layer along the vertical direction or the Z-axis direction, and wherein the first portion of the first layer and the second portion of the second layer are spaced apart along a direction perpendicular to the vertical direction.

17. The three-dimensional printing method according to claim 1, characterized in that, The first portion of the second layer is formed on the first portion of the first layer in a vertical direction, and in a plane perpendicular to the vertical direction or the Z-axis direction, the first portion at least partially surrounds the second portion.

18. The three-dimensional printing method according to claim 1, characterized in that, The first material is cured in a first region, and the second material is cured in a second region spaced apart from the first region.

19. The three-dimensional printing method according to claim 18, characterized in that, The first region is defined by a container for containing a first material, the second region is defined by a container for containing a second material, and the containers have at least a partially transparent bottom.

20. The three-dimensional printing method according to claim 18, characterized in that, The first region is defined by a plate-like element for carrying a first material, the second region is defined by a plate-like element for carrying a second material, and wherein the plate-like element has a bottom that is at least partially transparent.

21. The three-dimensional printing method according to claim 20, characterized in that, The first material is applied to the plate-like element used to support the first material via a nozzle, and / or The second material is applied to a plate-like element that carries the second material via a nozzle.

22. The three-dimensional printing method according to claim 1, characterized in that, The first material and / or the second material are applied to the material area of ​​the material holding mechanism through a nozzle.

23. The three-dimensional printing method according to claim 1, characterized in that, Also includes: After step (e), the target object is cleaned, and / or The target object is cleaned after step (g).

24. The three-dimensional printing method according to claim 23, characterized in that, The cleaning process includes at least one of the following: a rotary forming platform, wiping a three-dimensional object, applying airflow to the three-dimensional object, and surrounding the target object with an adsorbent to remove excess printing material.

25. The three-dimensional printing method according to claim 1, characterized in that, It also includes providing at least a third region, wherein the material applied in the third region is the same as or different from at least one of the first material and the second material.

26. The three-dimensional printing method according to claim 1, characterized in that, The second portion of the second plurality of layers has a uniform layer thickness.

27. The three-dimensional printing method according to claim 26, characterized in that, The second portion of the second plurality of layers at least partially surrounds the first portion of the second plurality of layers.

28. A three-dimensional printing method for manufacturing a target object, the target object comprising a first plurality of layers and a second plurality of layers, characterized in that, include: Provide a 3D printing device, the 3D printing device comprising: The material holding mechanism is configured to support the material. A forming platform is located above the material holding mechanism and configured to adhere the target object; The target object is formed using a base material, creating the first multiple layers (1~m, m≥2); and The target object is formed using a first material and a second material different from the first material, comprising a second plurality of layers (1 to n, n ≥ 3) including: (a) Curing a first material to form a first portion of a first layer of a second plurality of layers on the molding platform, the first portion of the first layer having a first thickness; (b) Control the molding platform to rise so as to separate the first portion of the first layer from the material holding mechanism; (c) Controlling the lower surface of the first portion of the first layer to form a first distance from the material holding mechanism, and curing the second material to form a second portion of the first layer in a second plurality of layers on the molding platform, the second portion of the first layer having a second thickness greater than the first thickness; (d) Control the molding platform to rise so as to separate the second portion of the first layer from the material holding mechanism; (e) Controlling the lower surface of the second portion of the first layer to form a second distance with the material holding mechanism, and curing the first material to form the first portion of the second layer of a second plurality of layers on the first portion of the first layer, wherein the total thickness of the first portion composed of the first material is greater than the total thickness of the second portion composed of the second material; (f) Control the molding platform to rise so as to separate the first portion of the second layer from the material holding mechanism; (g) Controlling the lower surface of the first portion of the second layer to form a third distance with the material holding mechanism, and curing the second material to form the second portion of the second layer of the second plurality of layers on the second portion of the first layer, wherein the total thickness of the second portion composed of the second material is greater than the total thickness of the first portion composed of the first material; (h) Repeat steps (d) and (g) to form a second or more layers of the target object; The target object is cleaned after at least one of steps (a) to (g).

29. A three-dimensional printing device for manufacturing a three-dimensional target object, said three-dimensional target object comprising a first plurality of layers (1~m, m≥2) and a second plurality of layers (1~n, n≥3), the second plurality of layers comprising at least two materials, characterized in that, The 3D printing equipment includes: The material holding mechanism is configured to support the material. A forming platform, located above the material holding mechanism, is configured to adhere the three-dimensional target object; A radiating device for radiating light onto the material-containing mechanism; and A drive mechanism configured to move at least one of the molding platform and the material holding mechanism; The 3D printing equipment is configured as follows: (a) The base material areas of the molding platform and the material holding mechanism are aligned by the driving mechanism, and the base material is cured by the radiation device to form a first plurality of layers of the target object on the molding platform; (b) The first material regions of the molding platform and the material holding mechanism are aligned by the driving mechanism, and the first material is cured by the radiation device to form a first portion of the first layer in a second plurality of layers, the first portion of the first layer having a first thickness; (c) The molding platform is raised by the driving mechanism to separate the first portion of the first layer from the material holding mechanism; (d) The second material regions of the molding platform and the material holding mechanism are aligned by the driving mechanism, and the lower surface of the first part of the first layer is made to form a first distance from the material holding mechanism. The second material is cured by the radiation device to form the second part of the first layer in a second plurality of layers. The second part of the first layer has a second thickness greater than the first thickness, wherein the first material and the second material are different. (e) The molding platform is raised by the drive mechanism to separate the second part of the first layer from the material holding mechanism; (f) The first material area of ​​the molding platform and the material holding mechanism are aligned by the driving mechanism, and the lower surface of the second part of the first layer is made to form a second distance with the material holding mechanism. The first material is cured by the radiation device to form the first part of the second layer of a second plurality of layers on the first part of the first layer, wherein the total thickness of the first part composed of the first material is greater than the total thickness of the second part composed of the second material. (g) The molding platform is raised by the driving mechanism to separate the first part of the second layer from the material holding mechanism; (h) The second material regions of the molding platform and the material holding mechanism are aligned by the driving mechanism, and the lower surface of the first part of the second layer forms a third distance with the material holding mechanism. The second material is cured by the radiation device to form the second part of the second layer of the second plurality of layers on the second part of the first layer, wherein the total thickness of the second part composed of the second material is greater than the total thickness of the first part composed of the first material. Repeat steps (e)-(h) to form a second plurality of layers of the target object.

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