Method for forming target object by additive manufacturing

Abstract

The present application provides a method for forming a target object by additive manufacturing. The target object comprises a first portion formed of a first material and a second portion formed of a second material different from the first material. The method comprises: acquiring a plurality of slice images of the first portion and a plurality of slice images of the second portion; using a first slice image among the plurality of slice images of the first portion, and irradiating a first printing region to cure the first material and form a first portion of a first layer of the target object; and using a first slice image among the plurality of slice images of the second portion, and irradiating a second printing region to cure the second material and form a second portion of the first layer of the target object, wherein in the building direction of the target object, the first portion of the first layer at least partially overlaps the second portion of the first layer.

Description

Methods of forming target objects through additive manufacturing

[0001] This application claims priority to Chinese patent applications filed on November 1, 2024, No. 202411553159.6, 202411553158.1, 202411553162.8, 202411553162.8, and 202411657229.2, 202411553162.8, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of additive manufacturing, and more specifically, to a method for forming a target object by additive manufacturing. Background Technology

[0003] Additive manufacturing (or 3D printing) technology creates three-dimensional entities by layering data from a three-dimensional model of an object. Additive manufacturing includes technologies such as FDM, SLS, SLA, DLP, and LCD. Photopolymerization technologies, represented by DLP and LCD, can manufacture products with high precision.

[0004] Currently, there is an increasing demand for products that require multiple materials. For example, the outer edges of a product may require a softer material, while the interior may require a harder material. Constructing a target object using multiple different materials via radiation is challenging. For instance, when constructing an object using multiple different materials, the molding platform used to adhere the object needs to switch between different containers holding different materials. There is a risk of mold falling off due to inconsistencies in the height of the different containers (adjacent cured layers not bonding).

[0005] For printing models with multiple colors or requiring multiple different materials (characterized by sections composed of various materials within the slice layers), it is necessary to research a multi-color slicing method to achieve one-time printing of multi-color or multi-material models. This would solve the problem of low printing efficiency for multi-material models (such as multi-color models) in existing technologies. Summary of the Invention

[0006] This application provides a method for forming a target object by additive manufacturing, the target object comprising a first part made of a first material and a second part made of a second material different from the first material, the method comprising: obtaining a plurality of slice images of the first part and a plurality of slice images of the second part; using the first slice image from the plurality of slice images of the first part and radiating a first printing area to cure the first material and form a first part of a first layer of the target object; using the first slice image from the plurality of slice images of the second part and radiating a second printing area to cure the second material and form a second part of the first layer of the target object, wherein, along the construction direction of the target object, the first part of the first layer and the second part of the first layer at least partially overlap.

[0007] In some embodiments, obtaining multiple slice images of the first part and multiple slice images of the second part includes: obtaining at least a data model of the first part of the target object and slicing the data model of the first part to obtain multiple slice images of the first part; and obtaining at least a data model of the second part of the target object and slicing the data model of the second part to obtain multiple slice images of the second part.

[0008] In some embodiments, obtaining multiple slice images of the first part and multiple slice images of the second part further includes: obtaining a data model of the target object, and then separating the data model of the target object to obtain a data model of the first part and a data model of the second part.

[0009] In some embodiments, obtaining multiple slice images of the first part and multiple slice images of the second part further includes: obtaining multiple slice images of the first part from a first dataset and obtaining multiple slice images of the second part from a second dataset.

[0010] In some embodiments, the method further includes: irradiating a first printed area using a second slice image from a plurality of slice images of the first portion to cure the first material to form a first portion of a second layer; and irradiating a second printed area using a second slice image from a plurality of slice images of the second portion to cure the second material to form a second portion of a second layer.

[0011] Wherein, along the construction direction of the target object, the first part of the second layer and the second part of the second layer at least partially overlap.

[0012] In some embodiments, among the multiple slice images of the first portion, there is at least one slice image spaced apart between the first slice image and the second slice image.

[0013] In some embodiments, multiple slice images of the first portion and multiple slice images of the second portion are obtained based on the same slice layer thickness.

[0014] In some embodiments, the plurality of slice images of the first portion include an initial slice image, a plurality of intermediate slice images, and an end slice image; the plurality of slice images of the second portion include an initial slice image, a plurality of intermediate slice images, and an end slice image; wherein the cured thickness associated with at least one intermediate slice image of the first portion is equal to the cured thickness associated with at least one intermediate slice image of the second portion.

[0015] This application also provides a method for forming a target object by additive manufacturing, the target object including a target segment, the target segment including a first part made of a first material and a second part made of a second material different from the first material, the method including: obtaining a first slice image for the target segment; irradiating a first printing area based on a first region of the first slice image to cure the first material to form a first part of a first layer of the target segment; and irradiating a second printing area based on a second region of the first slice image to cure the second material to form a second part of the first layer.

[0016] In some embodiments, along the construction direction of the target object, the first portion of the first layer and the second portion of the first layer at least partially overlap; or along the construction direction of the target object, the first portion of the first layer and the second portion of the first layer are tangent.

[0017] In some embodiments, obtaining a first slice map for a target segment includes: obtaining a single data model containing the target segment, and slicing the single data model to generate a first slice map for the target segment.

[0018] In some embodiments, obtaining a first slice image for a target segment includes: obtaining at least one slice image of a first data model, the first data model including a first portion of the target segment; obtaining at least one slice image of a second data model independent of the first data model, the second data model including a second portion of the target segment; and generating the first slice image based on at least one slice image of the first data model and at least one slice image of the second data model.

[0019] In some embodiments, generating the first slice based on at least one slice of the first data model and at least one slice of the second data model includes:

[0020] - Generate a first slice image associated with RGB information based on the grayscale information of at least one slice image of the first data model and the grayscale information of at least one slice image of the second data model; and / or

[0021] - Generate the first slice based on the size information of at least one slice from the first data model and the size information of at least one slice from the second data model, so that the first region is separated from the second region.

[0022] In some embodiments, the first region of the first slice image and the second region of the first slice image are configured in any of the following ways:

[0023] - Separated;

[0024] -Having a partially shared edge; or

[0025] - Has overlapping areas.

[0026] In some embodiments, the method further includes: after acquiring the first slice image, identifying a first region of the first slice image through first information, and identifying a second region of the first slice image through second information different from the first information, wherein the first information or the second information includes at least one of the following: color, grayscale, character, and shape.

[0027] In some embodiments, the method further includes: obtaining a second slice map for the target segment;

[0028] Based on the first region of the second slice image, the first printing region is radiated to solidify the first material to form the first part of the second layer; based on the first region of the second slice image, the second printing region is radiated to solidify the second material to form the second part of the second layer, wherein, along the construction direction, the first part of the second layer and the second part of the second layer at least partially overlap.

[0029] In some embodiments, the target object further includes a base portion located upstream or downstream of the first layer along the construction direction of the target object, wherein the base portion is selected from any one of the following: made of a first material; made of a second material; or made of a third material, wherein the third material is different from both the first and second materials.

[0030] In some embodiments, a first portion of the first layer has a first thickness, and a second portion of the first layer has a second thickness greater than the first thickness.

[0031] In some embodiments, the first thickness is 1% to 99% of the second thickness, for example 30% to 70%, for example 40% to 60%, for example 50%.

[0032] In some embodiments, the second thickness is 5 μm to 300 μm, for example 20 μm to 200 μm, for example 50 μm to 150 μm, for example 75 μm to 125 μm.

[0033] In some embodiments, the method further includes:

[0034] (i) A first portion of a second layer is formed on a first portion of a first layer, such that the total thickness of the first portion made of the first material is greater than the total thickness of the second portion made of the second material;

[0035] (ii) A second portion of the second layer is formed on the second portion of the first layer, such that the total thickness of the second portion made of the second material is greater than the total thickness of the first portion made of the first material;

[0036] ......

[0037] (iii) Form the first part of the (n+1)th layer on the first part of the nth layer, such that the total thickness of the first part made of the first material is greater than the total thickness of the second part made of the second material, n≥3;

[0038] (iv) Form a second part of the (n+1)th layer on the second part of the nth layer, such that the total thickness of the second part made of the second material is greater than the total thickness of the first part made of the first material.

[0039] In some embodiments, the data models of a first part of the target object and the data models of a second part of the target object are in contact at a target interface, and the actually formed first part and second part are in contact at a predetermined interface, wherein the predetermined interface and the target interface are at least partially spaced apart along a predetermined direction perpendicular to the construction direction.

[0040] This application also provides a method for forming a target object by additive manufacturing, the target object including a target layer, the target layer including a first target portion and a second target portion that contact at a target interface, the method including: projecting light onto a first carrier device through an optical unit to solidify a first material carried by the first carrier device and form a first solidified portion of the target layer of the target object; projecting light onto a second carrier device through an optical unit to solidify a second material carried by the second carrier device and form a second solidified portion of the target layer of the target object, the second material being different from the first material, wherein the first solidified portion and the second solidified portion contact at a predetermined interface and are at least partially spaced apart along a predetermined direction perpendicular to the construction direction of the target object.

[0041] In some embodiments, along the predetermined direction, the predetermined interface and the target interface are spaced at least a portion apart by 10 μm to 1000 μm.

[0042] In some embodiments, along the predetermined direction, the predetermined interface and the target interface are spaced at least a portion apart by 100 μm to 500 μm.

[0043] In some embodiments, the regions projected along the construction direction of the first target portion and the second target portion are equal to or substantially equal to the regions projected along the construction direction of the first cured portion and the second cured portion.

[0044] In some embodiments, the optical unit projects light based on a first pattern to form a first cured portion and projects light based on a second pattern to form a second cured portion, wherein the first pattern and the second pattern have overlapping portions.

[0045] In some embodiments, the grayscale value assigned to the overlapping portion of the first pattern is less than the grayscale value assigned to the remaining portion of the first pattern; or

[0046] The grayscale value of the overlapping portion of the second pattern is less than the grayscale value of the remaining portion of the second pattern.

[0047] In some embodiments, the width of the overlapping portion along a predetermined direction is determined based on the number of pixels, wherein the number of pixels is 1 to 10.

[0048] In some embodiments, along the construction direction, a portion of the predetermined interface is any of the following: straight, wavy, or serrated.

[0049] In some embodiments, the first thickness of the first cured portion is equal to the second thickness of the second cured portion.

[0050] In some embodiments, the first cured portion has a first thickness, and the second cured portion has a second thickness, wherein the first thickness is 1% to 99% of the second thickness, for example, 30% to 70%, for example, 40% to 60%, for example, 50%.

[0051] In some embodiments, the first thickness of the first cured portion is 5 μm to 200 μm, for example 20 μm to 180 μm, for example 50 μm to 150 μm, for example 75 to 125 μm.

[0052] In some embodiments, the first cured portion and the second cured portion partially overlap along the predetermined direction.

[0053] In some embodiments, the target layer further includes a third target portion, the third target portion contacting the second target portion at the second target interface, and the method further includes:

[0054] Light is projected onto the third carrier device through an optical unit to solidify the third material carried by the third carrier device, forming the third solidified portion of the target layer of the target object. This third material is different from the second material.

[0055] The third cured portion and the second cured portion contact each other at the second predetermined interface, and

[0056] Along a predetermined direction perpendicular to the Z-axis, the second predetermined interface and the second target interface are at least partially spaced apart.

[0057] In some embodiments, the target object includes at least two target layers that are adhered together.

[0058] In some embodiments, the length of the overlapping portion along the predetermined direction is determined based on the shrinkage rate of at least one of the first material and the second material.

[0059] This application also provides a 3D printing method for forming a target object by radiation, comprising: identifying a first slice image for first curing associated with a first material, the first slice image being assigned a first exposure parameter; identifying a second slice image for second curing associated with a second material, the first material being different from the second material, the second slice image being assigned a second exposure parameter; the first curing comprising: radiating the first material based on the first slice image and the first exposure parameter to form a first portion of the target object; after the first curing, performing a second curing; the second curing comprising: radiating a second material based on the second slice image and a modified second exposure parameter to form a second portion of the target object, the modified second exposure parameter being configured to increase the curing depth.

[0060] In some embodiments, identifying the first slice image for first curing as associated with the first material includes: identifying the first slice image as including only the portion associated with the cured first material; or identifying the first slice image as including: a first portion associated with the first material and a second portion associated with a material different from the first material.

[0061] In some embodiments, identifying that the second slice image for the second curing is associated with the second material includes: identifying that the second slice image includes only the portion associated with the cured second material; or identifying that the second slice image includes: a first portion associated with the second material and a second portion associated with a material different from the second material being cured.

[0062] In some embodiments, the altered second exposure parameter includes at least one of increased exposure power or extended exposure time.

[0063] In some embodiments, performing a second curing after the first curing includes performing a second curing immediately after the first curing.

[0064] In some embodiments, the method further includes:

[0065] Provides a first support device for carrying a first material and a second support device for carrying a second material;

[0066] Determine the distance between the bottom surfaces of the first and second support devices along the construction direction of the target object; and

[0067] Based on the distance, the changed second exposure parameter is determined.

[0068] In some embodiments, along the construction direction of the target object, the second part of the target object is formed on the first part of the target object.

[0069] In some embodiments, along the construction direction of the target object, the second part of the target object at least partially overlaps with the first part of the target object.

[0070] In some embodiments, the thickness of the second portion is greater than the thickness of the first portion.

[0071] In some embodiments, the method further includes: radiating a first material to form a third portion of the target object on a first portion, such that the total thickness of all portions made of the first material is greater than the total thickness of all portions made of the second material; and then radiating a second material to form a fourth portion of the target object on a second portion, such that the total thickness of all portions made of the second material is greater than the total thickness of all portions made of the first material.

[0072] In some embodiments, the maximum curing depth corresponding to the changed second exposure parameter is 1.1 to 2.5 times, preferably 1.2 to 1.8 times, the maximum curing depth corresponding to the second exposure parameter.

[0073] This application also provides a storage medium including a program configured to perform the aforementioned method. Attached Figure Description

[0074] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and therefore should not be regarded as a limitation on the scope of protection.

[0075] Figures 1A-1C show printed objects according to a certain embodiment;

[0076] Figure 2 is a slice diagram of the first height segment of the printed object in Figures 1A-1C;

[0077] Figure 3 is a slice diagram of the second height section of the printed object in Figures 1A-1C;

[0078] Figure 4 is a schematic diagram of the first height section of the printed object formed using an additive manufacturing system;

[0079] Figures 5A-5G illustrate the process of forming a second height segment of a printed object according to some embodiments;

[0080] Figures 6A-6I illustrate the process of forming a second height segment of a printed object according to some other embodiments;

[0081] Figure 7 is a slice diagram of the third height section of the printed object in Figures 1A-1C;

[0082] Figures 8A-8B show different parts of an object constructed based on slices;

[0083] Figure 9A shows the data model of the printed object;

[0084] Figure 9B shows the data model obtained by separating the data model from Figure 9A;

[0085] Figure 9C shows a slice of the data model of the printed object;

[0086] Figures 10A-10B show the slicing process of a printed object with a base section;

[0087] Figures 11A-11B show multiple slices used to form the single layer shown in Figures 10A-10B;

[0088] Figures 12A-12C show a single slice for forming the single layer shown in Figures 10A-10B, which has multiple regions for different materials;

[0089] Figures 13A-13C illustrate the steps of performing multiple exposures using different portions of a single slice image according to some embodiments;

[0090] Figures 14A-14C illustrate the steps of performing multiple exposures using different portions of a single slice image according to some other embodiments;

[0091] Figures 15A-15C illustrate the steps of performing multiple exposures using different portions of a single slice image according to yet another embodiment;

[0092] Figure 16 shows a solid tooth manufactured according to a printing method according to some embodiments, the solid tooth including a crown and gingiva;

[0093] Figure 17A is a schematic diagram of a data model according to some embodiments;

[0094] Figure 17B shows the ideal interface for different parts of the printed object in Figure 17A;

[0095] Figure 17C shows the actual interface of different parts of the printed object of Figure 17A according to some embodiments;

[0096] Figures 18A-18D show the interfaces or gaps of different portions of a single layer of a printed object according to some embodiments;

[0097] Figures 19A-19D show the interfaces or gaps of different portions of a single layer of a printed object according to other embodiments;

[0098] Figures 20A-20C show the interfaces of different parts of a printed object according to some embodiments;

[0099] Figures 21A-21G show the interfaces of different parts of a printed object according to some embodiments;

[0100] Figure 22 shows the interface of different parts of a printed object along the build direction according to some embodiments;

[0101] Figures 23A-23D illustrate embodiments of constructing an object using two support devices with a height difference;

[0102] Figure 24 is a schematic cross-section of an object formed using two materials according to some embodiments;

[0103] Figure 25 is a schematic cross-section of an object formed using two materials according to some other embodiments;

[0104] Figure 26 is a schematic cross-section of an object formed using two materials according to some other embodiments; and

[0105] Figures 27A-27D illustrate the process of forming an object using two materials.

[0106] In the accompanying drawings, some of the same or similar reference numerals represent some of the same or similar elements or components, and the scale of each part in the drawings is not necessarily true, but rather schematic. Detailed Implementation

[0107] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all of them. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application. The various elements, parts, and components in the embodiments provided in the present application can be combined with each other to form new embodiments when they do not contradict each other, and these should fall within the scope of protection of the present application.

[0108] The terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, or system, product, or apparatus that comprises a series of steps is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0109] Figures 1A-1C illustrate a target printed object according to an embodiment. As shown in Figures 1A-1B, the object 100 to be formed includes three parts 120, 140, and 160. The first part 120 is made of a first type of material A, the second part 140 is made of a second type of material B, and the third part 160 is made of a third type of material C.

[0110] In this paper, different types of materials refer to two materials having at least one different property. For example, material A and material B have different optical properties, such as their ability to absorb light and their light transmittance. Another example is that material A and material B have different physical properties, such as their color, elasticity, and yield strength. Yet another example is that material A and material B have different chemical properties, such as having different compositions.

[0111] In Figure 1C, the target object 100 is divided into three height segments Z1, Z2, and Z3. For example, when manufacturing the target object 100 using photopolymerization technology, such as DLP, material B is first cured during the manufacturing process of the first height segment Z1, then materials A, B, and C are cured during the manufacturing process of the second height segment Z2, and finally materials A and C are cured during the manufacturing process of the third height segment Z3.

[0112] In the first height segment Z1, the target object 100 comprises only a portion made of material B. In the second height segment Z2, the target object 100 has a portion made of material A, a portion made of material B, and a portion made of material C, wherein the portion made of material B is located between the portions made of material A and material C, and contacts them in the horizontal direction (or perpendicular to the height). In the third height segment Z3, the target object 100 has a portion made of material A and a portion made of material C, and they are spaced apart from each other in the horizontal direction.

[0113] Figure 2 shows a schematic cross-section of the target object in the first height segment Z1. The target object in the first height segment Z1 is formed from only one type of material B, and a portion 240 of the target object can be obtained by continuously curing to form multiple layers 241.

[0114] A portion 240 of the target object 100 is divided into multiple layers 241, for example, 200 layers. Each layer 241 has the same thickness, for example, 30 μm; or, it may have 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 speeding up the printing of the target object, while a smaller thickness is beneficial for obtaining better surface quality.

[0115] Figure 3 shows a cross-sectional schematic diagram of the target object in the second height segment Z2. The target object in the second height segment Z2 includes a first part 320 made of material A, a second part 340 made of material B, and a third part 360 made of material C. To manufacture the target object in the second height segment, the first part 320 is formed through multiple layers 321, the second part 340 is formed through multiple layers 341, and the third part 360 is formed through multiple layers 361.

[0116] Figure 4 shows a schematic diagram of a portion of an additive manufacturing system. The additive manufacturing system or 3D printing apparatus 400 includes a forming platform 410 for adhering a target object. Figure 4 shows a portion 442 of the target object (made of material B) that has been cured and adhered to the forming platform 410. In the embodiment shown in Figure 4, a plurality of supports 448, also made of material B, are formed to support this portion 442. In other embodiments, the supports 448 are made of a material C different from material B. The 3D printing apparatus 400 also includes a carrier device 480 for carrying or containing material B and an optical unit or radiation device 450 for projecting light onto the carrier device 480. For example, the optical unit 450 emits ultraviolet light of a predetermined wavelength (e.g., 385 nm or 405 nm) that penetrates at least a partially transparent bottom of the carrier device 480 and causes the printing material (e.g., photosensitive resin) carried by the carrier device 480 to cure. The carrier device 480 is provided with a film, for example, a film with a light transmittance of 80% to 90%. In Figure 4, the solidified target object 442 leaves the support device 480 containing material B.

[0117] Figure 5A shows a schematic diagram of a portion of an additive manufacturing system. For simplicity, optical units and some support devices are omitted. A portion 540 of a cured target object, made of material B, is adhered to a forming platform 510 of the additive manufacturing system. The additive manufacturing system drives at least one of the forming platform 510 or the support device 586 via a drive mechanism (not shown) to align the forming platform 510 with the support device 586, thereby allowing the material C carried by the support device 586 to be cured and adhered. Figure 5A shows a first portion 561 made of material C adhered to the portion 540 of the target object.

[0118] Figure 5B shows a schematic diagram of a portion of an additive manufacturing system. A molding platform 510 of the additive manufacturing system has portions 540, 561 of a cured target object adhered to it. The additive manufacturing system drives at least one of the molding platform 510 or the carrier device 584 via a drive mechanism (not shown) to align the molding platform 510 with the carrier device 584, thereby allowing material B carried by the carrier device 584 to be cured. Figure 5B shows a second portion 541 made of material B, which is adhered to a portion 540 of the target object and in contact with a first portion 561 made of material C. In the embodiment shown in Figure 5B, the first portion 561 and the second portion 541 have the same thickness and the same top or bottom surface; therefore, the first portion 561 and the second portion 541 can be interpreted as two portions of the same layer of the target object. Those skilled in the art will understand that the first portion 561 and the second portion 541 are both formed based on the surface exposure of the pattern. Therefore, the first portion 561 and / or the second portion 541 of the first layer of the entity can be understood as having a top surface and a bottom surface of equal area, and having a side surface extending perpendicular to the top surface and the bottom surface.

[0119] Figure 5C shows a schematic diagram of a portion of an additive manufacturing system. A molding platform 510 of the additive manufacturing system has portions 540, 561, 541 of a pre-cured target object adhered to it. The additive manufacturing system drives at least one of the molding platform 510 or the carrier device 582 via a drive mechanism (not shown) to align the molding platform 510 with the carrier device 582, thereby allowing material A carried by the carrier device 582 to be cured. Figure 5C shows a third portion 521 made of material A, which is adhered to a portion 540 of the target object and in contact with a first portion 541 made of material B. In the embodiment shown in Figure 5C, the first portion 561, the second portion 541, and the third portion 521 have the same thickness and the same top or bottom surface. In other words, the first portion 561, the second portion 541, and the third portion 521 completely overlap along the build direction of the target object, or the Z-axis direction, or the vertical direction. Therefore, the first part 561, the second part 541 and the third part 521 can be interpreted as three parts of a layer 501 of the target object.

[0120] Figures 5D-5F illustrate some states for manufacturing the target object. The target object includes a second layer 502 adhered to a first layer 501. The second layer 502 includes a first portion 562 made of material C (preferably as shown in Figure 5D), a second portion 542 made of material B (preferably as shown in Figure 5E), and a third portion 522 made of material A (preferably as shown in Figure 5F).

[0121] Figures 5D-5F illustrate three states cured in a specified order. Specifically, material C is first cured to form the first portion 562, then material B is cured to form the second portion 542, and finally material A is cured to form the third portion 542. In other embodiments, these three portions are formed in a different order. For example, material C is first cured to form the first portion 562, then material A is cured to form the third portion 542, and finally material B is cured to form the second portion 542. The order in which these three portions in the same layer are formed can be arbitrary.

[0122] Figure 5G shows the second height segment of the formed target object. In Figure 5G, the second height segment Z2 includes multiple layers 501, 502, ..., 508, each layer comprising three parts made of three different materials. For example, the last layer 508 includes a first part 568 made of material C, a second part 548 made of material B, and a third part 528 made of material A.

[0123] The embodiments shown in Figures 5A-5G demonstrate the manufacture of objects having different portions composed of different materials within the same layer. It is understood that the multiple layers of the second height segment Z2 may have the same or different thicknesses. For example, the first layer 501 has a thickness of 50 μm, the second layer 502 has a thickness of 50 μm, and the third layer 503 has a thickness of 60 μm. The thickness of each layer in the second height segment can be, for example, 20 μm–300 μm, 30 μm–200 μm, 40 μm–150 μm, 50 μm–100 μm, 60 μm, 70 μm, 80 μm, 80 μm, 82 μm, 83 μm, 85 μm, or 90 μm.

[0124] To manufacture a second height segment of the target object, this disclosure also provides an alternative. Figure 6A shows a schematic diagram of a portion of an additive manufacturing system. For simplification, optical units and some support devices are omitted. A portion 640 of the target object, made of material B, is adhered to a forming platform 610 of the additive manufacturing system 600. The additive manufacturing system drives at least one of the forming platform 610 or the support device 686 via a drive mechanism (not shown) to align the forming platform 610 with the support device 686, thereby allowing the material C carried by the support device 686 to be cured and adhered to the forming platform 610. Figure 6A shows a first portion 661 made of material C, which is adhered to the portion 540 of the target object and has a thickness t1.

[0125] Figure 6B shows a schematic diagram of a portion of an additive manufacturing system. Parts 640, 661 of a cured target object are adhered to a molding platform 610 of the additive manufacturing system. The additive manufacturing system drives at least one of the molding platform 610 or the carrier device 684 via a drive mechanism (not shown) to align the molding platform 610 with the carrier device 684. Figure 6B shows a second part 641 made of material B, which is adhered to a portion 640 of the target object and in contact with a first part 661 made of material C. The second part 641 has a thickness t2. Specifically, the first part 661 and the second part 641 have top surfaces of the same height (i.e., the surfaces in contact with the cured portion 640), but bottom surfaces of different heights opposite to the top surfaces.

[0126] As shown in Figure 6B, the thickness t2 of the second portion 641 is greater than the thickness t1 of the first portion 661. Those skilled in the art will understand that the forming platform of an additive manufacturing system can be driven to move in a vertical direction (or the stacking direction of the slice layers), but errors in the accuracy of the movement are unavoidable. For example, the positioning accuracy of the drive device used to drive the forming platform or carrier device to move in a vertical direction is 25 μm / 300 mm. On the other hand, due to installation errors, the heights of the two carrier devices 684 and 686 may be inconsistent; for example, carrier device 684 may be 25 μm higher than carrier device 686, or carrier device 684 may be 35 μm lower than carrier device 686.

[0127] In one example, the material C carried by the support device 686 is cured to form a first portion 661 with a thickness of 50 μm. The forming platform 610 carrying the first portion 661 is raised 300 mm and then moved horizontally (e.g., translated or rotated) from a position aligned with the support device 686 to a position aligned with the support device 684. The forming platform 610 then descends 300 mm to prepare for curing a second portion 641 with a thickness of 50 μm. Due to the positioning accuracy (25 μm / 300 mm) of the drive device used to drive the forming platform vertically, after descent, the forming platform 610 may actually descend 20 μm more than the ideal 300 mm. This would cause the cured first portion 661 to contact the flexible membrane of the support device 684 and move downwards by 20 μm. Such movement scenarios occur repeatedly during the manufacturing of the second height section of the target object, increasing the risk of the cured portion being damaged by the downward pressure on the flexible membrane of the support device. On the other hand, the flexible membrane of the bearing device 684 is repeatedly pressed down by the cured portion and pulled up when the new cured portion is peeled off, which reduces the membrane's lifespan.

[0128] When the thickness t2 of the second portion 641 is greater than the thickness t1 of the first portion 661, the risk caused by the aforementioned motion error is reduced. For example, the material C carried by the support device 686 is cured to form a first portion 661 with a thickness of 50 μm. The molding platform 610 carrying the first portion 661 is raised by 300 mm and then moved horizontally (e.g., translated or rotated) from a position aligned with the support device 686 to a position aligned with the support device 684. Then, the molding platform 610 descends by 299.9 mm to prepare for curing the second portion 641 with a thickness of 100 μm. Due to the positioning accuracy (25 μm / 300 mm) of the drive device used to drive the molding platform to move in the vertical direction, after descending, the molding platform 610 may actually descend by 20 μm more than the ideal value of 299.9 mm. This will cause the cured first portion 661 to descend by 20 μm more, at which point the first portion 661 is 30 μm away from the flexible film of the support device 684 without contacting the flexible film.

[0129] When the thickness t2 of the second part 641 is greater than the thickness t1 of the first part 661, the risk caused by the aforementioned installation error is reduced. For example, the material C carried by the support device 686 is cured to form a first part 661 with a thickness of 50 μm. The forming platform 610 carrying the first part 661 is raised by 300 mm and then moved horizontally (e.g., translated and / or rotated) from a position aligned with the support device 686 to a position aligned with the support device 684. Then, the forming platform 610 is lowered by 299.9 mm to prepare for curing the second part 641 with a thickness of 100 μm. For example, when the support device 686 is 15 μm lower than the support device 684, and the forming platform 610 is actually lowered by 299.9 mm according to control, the cured first part 661 is 35 μm away from the flexible film of the support device 684, and the cured part 640 is 85 μm away from the flexible film of the support device 684. Neither of them will contact the flexible film.

[0130] Figure 6C shows a schematic diagram of a portion of an additive manufacturing system. Parts 640, 661, and 641 of a cured target object are adhered to a forming platform 610 of the additive manufacturing system. The additive manufacturing system drives at least one of the forming platform 610 or the carrier device 682 via a drive mechanism (not shown) to align the forming platform 610 with the carrier device 682. Figure 6C shows a third part 621 made of material A, which is adhered to a portion 640 of the target object and in contact with a second part 641 made of material B. The third part 621 has a thickness t3. Specifically, the first part 661, the second part 641, and the third part 621 have top surfaces of the same height (i.e., the surfaces in contact with the cured portion 640), but bottom surfaces of different heights opposite to the top surfaces. Similarly, the thickness t3 of the third part 621 is greater than the thickness t2 of the second part 641. Along the construction direction of the target object, or the Z-axis direction, or the vertical direction, or the stacking direction of the layers, any two adjacent parts of the first part 661, the second part 641, and the third part 621 partially overlap each other.

[0131] Those skilled in the art will understand that the first part 661, the second part 641 and the third part 621 are all formed based on the surface exposure of the pattern. Therefore, any one of the first part 661, the second part 641 and the third part 621 of the first layer 601 of the target object can be understood as having a top surface and a bottom surface with equal areas, and having a side surface extending perpendicular to the top surface and the bottom surface.

[0132] The first part 661, the second part 641, and the third part 621 can be interpreted as three portions of a layer 601 of the target object. This layer 601 is not a slice layer, but a layer that includes the solidified product. The first part 661, the second part 641, and the third part 621 of the first layer 601 of the target object have different thicknesses. In the order of formation, the thickness of the later formed portion is greater than the thickness of the earlier formed portion, which can reduce the risk, for example, due to positioning accuracy issues caused by vertical movement. In other embodiments, curing or printing can be performed in the following order: first, curing material C to form the first part 661 with a thickness t1'; then, curing material A to form the third part 621 with a thickness t3' (t3' > t1'); and finally, curing material B to form the second part 641 with a thickness t2 (t2' > t3').

[0133] Figures 6D-6F illustrate some states used in manufacturing the target object. The target object includes a second layer 602 adhered to a first layer 601. Similar to the first layer, the second layer 602 has three regions of different thicknesses. The second layer 602 includes a first portion 662 made of material C (ideally as shown in Figure 6D), a second portion 642 made of material B (ideally as shown in Figure 6E), and a third portion 622 made of material A (ideally as shown in Figure 6F).

[0134] As shown in Figure 6D, the first portion 662 of the second layer 602 has a thickness t4, such that the total thickness of the first portion composed of material C (i.e., the sum of the first portions 661 of the first layer 601 and 662 of the second layer 602) is greater than the total thickness of the third portion composed of material A. Of course, the total thickness t3 of the third portion 621 composed of material A is greater than the total thickness t2 of the second portion 641 composed of material B. In some embodiments, thickness t4 is equal to thickness t3. In some embodiments, thickness t4 is not equal to thickness t3, but t1 + t4 > t3.

[0135] As shown in Figure 6E, the second portion 642 of the second layer 602 has a thickness t5, such that the total thickness of the second portion composed of material B (i.e., the sum of the second portions 641 of the first layer 601 and 642 of the second layer 602) is greater than the total thickness of the first portion composed of material C (i.e., the sum of the first portions 661 of the first layer 601 and 662 of the second layer 602). In some embodiments, the thickness t5 of the second portion 642 is equal to the thickness t4 of the first portion 662, which is beneficial for the design of process parameters during the slicing process in 3D printing. In some embodiments, the thickness t5 of the second portion 642 is not equal to the thickness t4 of the first portion 662, but t2+t5>t1+t4.

[0136] As shown in Figure 6F, the third portion 622 of the second layer 602 has a thickness t6, such that the total thickness of the third portion composed of material A (i.e., the sum of the third portion 621 of the first layer 601 and the third portion 622 of the second layer 602) is greater than the total thickness of the second portion composed of material B (i.e., the sum of the second portion 641 of the first layer 601 and the second portion 642 of the second layer 602). In some embodiments, the thickness t6 of the third portion 622 is equal to the thickness t4 of the first portion 662, which is beneficial for the design of process parameters during the slicing process in 3D printing. In some embodiments, the thickness t6 of the third portion 622 is not equal to the thickness t4 of the first portion 662, but t3 + t6 > t2 + t5.

[0137] In the embodiments shown in Figures 6A-6F, the thicknesses of these portions of the first and second layers can be configured with various parameters. For example, the thickness t1 of the first portion 661 of the first layer 601 is 1%-90% of the thickness t3 of the third portion 621 of the first layer 601, preferably 30%-70%, more preferably 40%-60%. The thickness t2 (t2 > t1) of the second portion 641 of the first layer 601 is 10%-90% of the thickness t3 of the third portion 621 of the first layer 601, preferably 30%-70%, more preferably 40%-66%.

[0138] As an example, the thickness t1 of the first part 661 of the first layer 601 is one-third of the thickness t3 of the third part 621 of the first layer 601, and the thickness t2 of the second part 641 of the first layer 601 is two-thirds of the thickness t3 of the third part 621 of the first layer 601.

[0139] As an example, the thickness t4 of the first part 662 of the second layer 602 is equal to the thickness t5 of the second part 642 of the second layer 602, and the thickness t5 of the second part 642 of the second layer 602 is equal to the thickness t6 of the third part 622 of the second layer 602. This is beneficial for the design of process parameters in the slicing process in 3D printing.

[0140] As an example, the thickness t4 of the first part 662 of the second layer 602 is equal to the third thickness t3 of the third part 621 of the first layer 601, and t4 = t5 = t6, which makes the total thickness (t3 + t6) of the third part composed of material A twice the third thickness (t3).

[0141] Figure 6G illustrates a third layer for manufacturing the second height segment of the target object. The third layer 603 adheres to the second layer 602. Similar to the second layer 602, the third layer 603 has three regions of different thicknesses. The third layer 603 includes a first portion 663 made of material C, a second portion 643 made of material B, and a third portion 623 made of material A. The second height segment Z2 of the target object is defined by an initial axis L1 and an end axis L2. In the embodiment shown in Figure 6G, the third layer 603 has reached the end axis L2, meaning that printing cannot continue in the manner in which the second layer 602 and the third layer 603 are formed because the thickness of the portion to be cured in the second height segment is insufficient. During the formation of the unformed portion in the second height segment, there is a risk that the third portion 623 of the third layer 603 may press down on the transparent film of the carrier device. However, the unformed portion in the second height segment shown in Figure 6G is only a small portion of the second height segment, and this risk is tolerable to those skilled in the art.

[0142] Figures 6H-6I illustrate the end compensation layer for the second height segment of the target object. The end compensation layer, or fourth layer 604, is adhered to the third layer 603. The end compensation layer, or fourth layer 604, has two portions of different thicknesses. Specifically, the fourth layer 604 includes a second portion 644 made of material B and a first portion 664 made of material C, the first portion 664 being thicker than the second portion 644.

[0143] Although Figures 6H-6I show the second portion 644 of the fourth layer 604 being formed first, followed by the first portion 664 of the fourth layer 604, in other embodiments, the first portion 664 of the fourth layer 604 may be formed first, followed by the second portion 644 of the fourth layer 604.

[0144] Figures 6A-6I illustrate the steps for manufacturing the second height segment of the target object. Those skilled in the art will understand that, depending on the total thickness of the second height segment of the target object, the target object may have multiple second or third layers. For example, after forming the first layer (or “initial compensation layer”), 100 layers (or “intermediate layers”) are formed consecutively in a manner that forms the second or third layer, and finally, the end compensation layer of the second height segment is formed in a manner that forms the fourth layer.

[0145] The embodiments shown in Figures 6A-6I demonstrate the manufacture of objects having different portions composed of different materials within the same layer. It is understood that the multiple intermediate layers of the second height segment Z2 may have the same or different thicknesses. For example, each portion 662, 642, 622 of the second layer 602 (i.e., the first of the multiple intermediate layers) has a thickness of 50 μm, and each portion 663, 643, 623 of the third layer 603 (i.e., the second of the multiple intermediate layers) has a thickness of either 70 μm or 50 μm.

[0146] The formation of each portion of each layer in the second height segment of the target object is associated with the corresponding slicing parameters. The slicing of the target object may include an initial slicing layer, multiple intermediate slicing layers, and an end slicing layer. For example, a 3D object data model has 500 slice layers, each slice layer being 50 μm thick. An alternating curing strategy can be used from layer 100 to layer 300. For instance, first, a 50 μm thick material C is cured to form the first part of the first layer of the second height segment; then, a 100 μm thick material B (i.e., twice the slice layer thickness) is cured to form the second part of the first layer of the second height segment; next, a 150 μm thick material A (i.e., three times the slice layer thickness) is cured to form the third part of the first layer of the second height segment; then, a 150 μm thick material C (i.e., three times the slice layer thickness) is cured to form the first part of the second layer of the second height segment; then, a 150 μm thick material B is cured to form the second part of the second layer of the second height segment; then, a 150 μm thick material A is cured to form the third part of the second layer of the second height segment; ...; the steps shown in Figures 6A-6I are executed continuously until the end compensation layer of the second height segment is formed.

[0147] The initial slice layer of the target object can be used to form the initial compensation layer of the second height segment, the intermediate slice layer of the target object can be used to form the intermediate layer of the second height segment, and the final slice layer of the target object can be used to form the final compensation layer of the second height segment. The thickness of the target object slice can be designed, for example, 2μm to 200μm, 5μm to 150μm, 10μm to 100μm, 20μm to 80μm, 25μm to 75μm, 30μm to 60μm, 40μm, or 50μm.

[0148] Figure 7 illustrates one printing state of the target object. The first portion 720 and the third portion 760 of the target object are not yet printed, while the second portion 740 has been printed, for example, as shown in Figures 5A-5G or 6A-6I. The third height segment Z3 of the target object involves the third portion 760 made of material C and the first portion 720 made of material A. Similarly, the third portion 760 and the first portion 720 in the third height segment Z3 of the target object are divided into multiple slice layers with the same or different slice thicknesses.

[0149] Figures 8A-8B illustrate the different parts of an object constructed based on slices. As shown in Figure 8A, the first layer of the object includes a first part 821 made of material A and a second part 841 made of material B. As shown in Figure 8B, the second layer of the object includes a first part 822 made of material A and a second part 842 made of material B. The object comprises multiple similar layers, each layer including a first part and a second part.

[0150] It is understood that the first layer shown in Figures 8A-8B is formed on a molding platform. Alternatively, the first layer shown in Figures 8A-8B is formed on a base portion. Optionally, an additional base portion is formed on the second layer shown in Figures 8A-8B. The material of the base portion or the additional base portion can be a first material, a second material, or a third material different from the first and second materials.

[0151] To form a portion of the first or second layer as shown in Figures 8A-8B, the slices can be configured in a variety of ways.

[0152] In some embodiments, the object comprises different parts made of different materials. For example, the object comprises a first part made of a first material and a second part made of a second material. First, the object's data model is split to obtain two independent data models: a data model for the first part and a data model for the second part. The data model for the first part is sliced ​​to obtain multiple slice images of the first part, and the data model for the second part is sliced ​​to obtain multiple slice images of the second part.

[0153] During printing, for example, a slice from a plurality of slices of the first portion is used, and the printing area carrying the first material is irradiated to cure the first material and form the first portion 821 of the first layer. Then, a slice from a plurality of slices of the second portion is used, and the printing area carrying the second material is irradiated to cure the second material and form the second portion 841 of the first layer. At this point, the first layer is formed.

[0154] Subsequently, another slice from the multiple slices of the first part is used, and the printed area carrying the first material is radiated to cure the first material and form the first part 822 of the first layer. Then, another slice from the multiple slices of the second part is used, and the printed area carrying the second material is radiated to cure the second material and form the second part 842 of the first layer. At this point, the second layer is formed. The stacking direction of the first and second layers is the construction direction of the object. Along the construction direction, the first part of the first layer at least partially overlaps the second part of the first layer.

[0155] To provide a more detailed example, when a user expects to print an object having a first part and a second part (e.g., a first part made of material M and a second part made of material N that are the same height and adjacent), the user can slice the object based on the data model of the first part alone, thus obtaining multiple slice images of the first part, which are saved in a folder, compressed file, or dataset A. The user also slices the object based on the data model of the second part alone, thus obtaining multiple slice images of the second part, which are saved in a folder, compressed file, or dataset B.

[0156] When printing is performed, a first slice image from multiple (e.g., 100) slice images of a first portion is first retrieved from dataset A. This first slice image is obtained based on a slice layer thickness of 50 μm. Then, an optical unit (e.g., a DMD assembly for DLP printing) projects light onto a first container containing material M, causing material M to cure to a curing depth (or curing thickness) of 50 μm, forming a first portion of the first layer. Subsequently, a forming platform carrying the cured portion moves to a second container containing material N. A first slice image from multiple (e.g., 50 or 100) slice images of a second portion is retrieved from dataset B. This first slice image is obtained based on a slice layer thickness of 100 μm. Then, an optical unit (e.g., a DMD assembly for DLP printing) projects light onto a second container containing material N, causing material N to cure to a curing depth of 100 μm, forming a second portion of the first layer. This results in a 50μm overlap and a 50μm non-overlapping area between the first part and the second part of the first layer (along the construction direction of the first or second part, or along the stacking direction of the slice layer, or along the Z-axis).

[0157] After the first layer is formed, the forming platform can carry the cured portion to a first container containing material M. A second slice image from a set of 100 slice images of the second portion, obtained based on a slice layer thickness of 100 μm, can be retrieved from dataset A. Then, an optical unit projects light onto the first container containing material M, causing material M to cure to a curing depth of 100 μm, forming the first portion of the second layer. This results in a 50 μm overlap area and a 50 μm non-overlap area between the first portion of the second layer and the second portion of the first layer (along the construction direction of the first or second portion, or along the stacking direction of the slice layers).

[0158] After the first part of the second layer is formed, the forming platform can carry the cured portion to a second container containing material N. A second slice image from multiple slice images (100 in total) of the second part, obtained based on a slice layer thickness of 100 μm, can be retrieved from dataset B. Then, an optical unit projects light onto the second container containing material N, causing material N to cure to a curing depth of 100 μm, forming the second part of the second layer. This results in a 50 μm overlap area and a 50 μm non-overlap area between the first and second parts of the second layer (along the construction direction of the first or second part, or along the stacking direction of the slice layers). Continuous printing using the above scheme yields the desired target object.

[0159] Since the two data models are sliced ​​separately, the slicing parameters (especially the slice layer thickness) can be different.

[0160] In one example, the target object has a first part and a second part with the same height and thickness. The first part, with a total thickness of 5000 μm, is divided into 100 layers, each with a thickness of 50 μm, resulting in 100 slice images (numbered A1, A2, A3, ..., A100); the second part, with a thickness of 5000 μm, is divided into 50 layers, each with a thickness of 100 μm, resulting in 50 slice images (numbered B1, B2, B3, ..., B50). During printing, slice image numbered "A1" is retrieved from the first dataset A (100 images) used for the first part, and printed based on a curing thickness of 50 μm to form the first layer of the first part. Slice image numbered "B1" is retrieved from the second dataset B (50 images) used for the second part, and printed based on a curing thickness of 100 μm to form the first layer of the second part. Then, slice images numbered "A2" or "A3" are retrieved from the first dataset A used for the first part, and printed based on a curing thickness of 100 μm to form the first part of the second layer. Slice images numbered "B2" are retrieved from the second dataset B used for the second part, and printed based on a slice thickness (or curing thickness) of 100 μm to form the second part of the second layer. Slice images numbered "A4" or "A5" are retrieved from the first dataset A used for the first part, and printed based on a curing thickness of 100 μm to form the first part of the third layer. Slice images numbered "B3" are retrieved from the second dataset B used for the second part, and printed based on a slice thickness (or curing thickness) of 100 μm to form the second part of the third layer.

[0161] In another example, the target object has a first part and a second part with the same height and the same thickness. The first part, with a thickness of 5000 μm, is divided into 100 layers, each with a thickness of 50 μm, resulting in 100 slice images (numbered A1, A2, A3, ..., A100); the second part, with a thickness of 5000 μm, is divided into 100 layers, each with a thickness of 50 μm, resulting in 100 slice images (numbered B1, B2, B3, ..., B100). During printing, slice image numbered "A1" is retrieved from the first dataset A (100 images) used for the first part, and printed based on a curing thickness of 50 μm to form the first part of the first layer. Slice images numbered "B1" or "B2" are retrieved from the second dataset B (100 images) used for the second part, and printed based on a curing thickness of 100 μm to form the second part of the first layer. From the first dataset A used for the first part, retrieve 100 slice images numbered "A2" or "A3" and print them with a curing thickness of 100 μm to form the second layer of the first part. From the second dataset B used for the second part, retrieve slice images numbered "B3" or "B4" and print them with a slice thickness (or curing thickness) of 100 μm to form the second part of the second layer. From the first dataset A used for the first part, retrieve slice images numbered "A4" or "A5" and print them with a curing thickness of 100 μm to form the first part of the third layer. From the second dataset B used for the second part, retrieve slice images numbered "B5" or "B6" and print them with a slice thickness (or curing thickness) of 100 μm to form the second part of the third layer.

[0162] It is understandable that the actual curing thickness is equal to the slice thickness associated with the slice image during the slicing process in some scenarios, but not in other scenarios.

[0163] In some embodiments, multiple slice images of the first part and multiple slice images of the second part are assigned the same slice layer thickness and / or curing thickness. For example, during the slicing stage, the slice layer thickness of each slice image of the first part and the second part is the same, such as 20 μm, 50 μm, or 100 μm. After obtaining the slice images, printing can be performed according to different curing depths (or curing thicknesses). For example, if there are 30 slice images (numbered 1 to 30) based on a slice layer thickness of 20 μm, a 20 μm thick material can be cured first based on slice image number "1", followed by a 40 μm thick material based on slice image number "3", and a 60 μm thick material based on slice image number "6".

[0164] In some embodiments, the first part includes 200 slice images, namely an initial slice image with a slice layer thickness of 50 μm (numbered A1), multiple intermediate slice images with a slice layer thickness of 100 μm (numbered A2 to A199), and an end slice image with a slice layer thickness of 50 μm (numbered A200). The second part includes 199 slice images, namely an initial slice image with a slice layer thickness of 100 μm (numbered B1), multiple intermediate slice images with a slice layer thickness of 100 μm (numbered B2 to B198), and an end slice image with a slice layer thickness of 100 μm (numbered B199). During printing, the slice images can be called in the order of numbered A1, B1, A2, B2, A3, B3, ..., A199, B199, A200, at which time the slice layer thickness is the same as the curing depth.

[0165] In some embodiments, the first part includes 200 slice images, namely an initial slice image with a slice layer thickness of 50 μm (numbered A1), a plurality of intermediate slice images with a slice layer thickness of 60 μm (numbered A2 to A100), a plurality of intermediate slice images with a slice layer thickness of 70 μm (numbered A101 to A198), an intermediate slice image with a slice layer thickness of 80 μm (numbered A199), and an end slice image with a slice layer thickness of 20 μm (numbered A200).

[0166] The second part includes 199 slice images: an initial slice image with a slice thickness of 70μm (numbered B1), multiple intermediate slice images with a slice thickness of 60μm (numbered B2 to B100), multiple intermediate slice images with a slice thickness of 70μm (numbered B101 to B198), and an end slice image with a slice thickness of 80μm (numbered B199). When printing, the slice images can be called in the order of A1, B1, A2, B2, A3, B3, ..., A199, B199, A200, at which point the slice thickness is the same as the curing depth.

[0167] Those skilled in the art will understand that in 3D printing, the term "slice map" refers to a slice image (e.g., in PNG format), a scan path, or a GCode path file, etc. In other words, slice map-based operations are, for example, operations based on a slice map, a scan path, or a GCode path.

[0168] Figure 9A shows a tooth model comprising a gingival portion and a tooth portion. To resemble a real tooth, the fabricated gingival portion is, for example, red, and the tooth portion is white. Accordingly, the desired tooth model includes both red and white portions.

[0169] Figure 9B shows the separated gingival portion (left) and tooth portion (right). For example, by using third-party software or a tooth segmentation algorithm, the teeth and gingiva shown in Figure 9A can be segmented along the gingival line to obtain the two models in Figure 9B.

[0170] In some embodiments, the tooth model is not colored; however, each part of the tooth model is associated with color information. In some embodiments, the tooth model is colored, and the resulting slice images are also color images.

[0171] During the process of determining the slice image, color information of the gingival and / or dental portions can be read. This color information can be, for example, (R, G, B) color values ​​defined by the user based on the actual model conditions. For instance, the color of the gingival portion can be set to (255, 0, 255), and the color of the dental portion to (255, 255, 255). A set of slice planes is generated based on the pre-set layer thickness and model height, with the distance between the slice planes being the set layer height. Then, the faces (e.g., triangular faces) of the dental and gingival portions are grouped according to whether they intersect with the slice planes. Faces intersecting with the slice planes are grouped together, resulting in multiple groups of faces. For each group of faces, the intersection contour lines between the slice planes and the faces are calculated. Based on the topological relationship of the faces, the intersecting contour lines are connected into closed contour lines, which are then mapped onto the slice image. At input, the gingival portion corresponds to the color (128, 0, 0), and the dental portion corresponds to the color (255, 255, 255). When mapping the contour lines onto the slice image, the corresponding colors can be assigned based on the input color values. The internal regions of the contour map are filled using a line-scan filling algorithm, and the grayscale values ​​of the contour are calculated using an anti-aliasing method. The color value corresponding to the gingiva is (128, 0, 0), so the internal fill color is (128, 0, 0); the contour corresponding to the teeth is (255, 255, 255), so the internal fill color is (255, 255, 255). After filling, a complete slice image is obtained, as shown in Figure 9C. The slice image can be saved as a PNG file, for example. Multiple slice images can be output to a compressed file, for example. Through the above steps, the slice images for the teeth and gingiva regions are determined separately.

[0172] Figure 10A shows a schematic diagram of the target object 1000. Referring to Figure 10A, the target object 1000 to be formed includes a first part 1020, a second part 1040, and a third part 1060. The first part 1020 is composed of a base material A, the second part 1040 is composed of a first type of material B, and the third part 1060 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. The first material B is different from the second material C. Figure 10B is a schematic diagram of a slice of the target object 1000. Referring to Figure 10B, the target object 1000 is sliced ​​to obtain multiple slice images, including multiple slice images of the first part 1020, multiple slice images of the second part 1040 (or a first set of slice images), and multiple slice images of the third part 1060 (or a second set of slice images). The first part 1020 comprises multiple slice images including slice image 1021, slice image 1022, ... up to slice image ith, where i ≥ 3. The second part 1040 comprises multiple slice images (or a first group of slice images) including slice image 1041, slice image 1042, slice image 1043, ... up to slice image ith, where m ≥ 4. The third part 1060 comprises multiple slice images (or a second group of slice images) including slice image 1061, slice image 1062, slice image 1063, ... up to slice image ith, where n ≥ 4. The second part 1040 of the target object 1000 is divided into multiple layers, for example, 200 layers. Each layer has the same thickness, for example, 30 μm; or, they have different thicknesses, for example, some layers have a thickness of 30 μm and some have a thickness of 50 μm. Similarly, the third part 1060 of the target object 1000 is divided into multiple layers, such as 500 layers. Each layer has the same thickness, such as 30 μm; or, they can have different thicknesses, such as some layers having a thickness of 30 μm and others having a thickness of 50 μm. Larger thicknesses are beneficial for speeding up the printing of the target object, while smaller thicknesses are beneficial for obtaining better surface quality.

[0173] Figures 11A-11B show schematic diagrams of the projection of the target object. As shown in Figures 11A-11B, the computer unit can identify individual slice images. The first layer slice image 1141 of the first set of slice images is retrieved and cured to form the first layer of the second part of the target object. The first layer slice image 1161 of the second set of slice images is retrieved and cured to form the first layer 1161 of the third part of the target object. The first and second sets of slice images are called alternately. During printing, the first material is first cured according to the pattern (rectangle) of the first set of slice images (ideally as shown in Figure 11A), and then the second material, different from the first material, is cured according to the pattern (circle) of the second set of slice images (ideally as shown in Figure 11B). In some embodiments, the curing depth for the first material is the same as the curing depth for the second material, for example, a curing depth of 40 μm, 50 μm, 75 μm, 100 μm, or 150 μm. In some embodiments, the curing depth for the first material is different from the curing depth for the second material, for example, the curing depths are 25 μm and 50 μm, respectively. For example, the curing depths are 40 μm and 60 μm, for example, the curing depths are 50 μm and 100 μm, for example, the curing depths are 75 μm and 150 μm, respectively.

[0174] In some embodiments, the entire target object (which includes a first part A and a second part B) can be sliced, and each of the resulting slice images includes a first region for the first part A and a second region for the second part B. Printing can be performed based on different regions of different slice images to obtain the desired result. For example, the target object includes a first part A and a second part B of equal height and thickness. The data model of the target object is sliced ​​to obtain 100 slice images (or 100 slice layers), numbered "1, 2, 3, ..., 100". Based on the first region (related to the first part A) in the slice image numbered "1", the first part A is constructed using a first material; then based on the second region (related to the second part B) in the slice image numbered "2", the second part B is constructed using a second material; then based on the first region (related to the first part A) in the slice image numbered "3", the first part A is constructed using a first material; then based on the second region (related to the second part B) in the slice image numbered "4", the second part B is constructed using a second material.

[0175] Figures 12A-12C illustrate another projection diagram of the target object. As shown in Figures 12A-12C, the entire target object (which includes a first part A and a second part B) is sliced, and each of the resulting slice images includes a first region 1241 for the first part A and a second region 1261 for the second part B. The data model of the target object is sliced ​​to obtain 100 slice images (or 100 slice layers), numbered "1, 2, 3, ..., 100". Based on the first region 1241 (related to the first part A) in the slice image numbered "1", the first part A is constructed using a first material; then based on the second region 1261 (related to the second part B) in the slice image numbered "2", the second part B is constructed using a second material. Therefore, different parts of a single slice image can be identified by a computer unit. When retrieving slice image number "1", only the first region 1241 in the projection image is cured to form the first part of the first layer of the target object; the second region is not displayed / exposed at this time. When retrieving slice image number "2", only the second region 1261 in the projection image is formed to form the third part of the first layer of the target object; the first region is not displayed / exposed at this time. Specifically, during printing, the first material is first cured according to the pattern (rectangle) of the slice image (ideally as shown in Figure 12B), and then the second material, which is different from the first material, is cured according to the pattern (circle) of the slice image (ideally as shown in Figure 12C). This alternating retrieval of slice images after recognition completes the printing of the target object.

[0176] Those skilled in the art will understand that the computer unit can identify different parts of a single slice image, for example, different parts carrying identification information. Identification information includes at least one of the following: color, characters (numbers, letters, etc.), shape, annotations, etc. Identification information can be associated with corresponding parts of a single slice image at multiple stages.

[0177] When a user desires to print an object having a first part and a second part (e.g., a first part made of material M and a second part made of material N are of equal height and adjacent), the user can slice the target part of a single data model (containing both the first and second parts) to obtain multiple slices of the target part of the data model. Each slice contains a first region involving the first part and a second region involving the second part. These slices are saved in a single folder, compressed file, or dataset.

[0178] When printing is performed, a first slice image can be retrieved from a dataset of multiple slice images (e.g., 100) of the target object. This first slice image is obtained based on a slice layer thickness of 50 μm. After identifying a first region of the first slice image, an optical unit (e.g., a DMD component for DLP printing) projects light onto a first container containing material M based on the pattern of the first region, so that material M is cured to form a first portion of the first layer at a curing depth (or curing thickness) of 50 μm.

[0179] After forming the first portion of the first layer, the forming platform can carry the cured portion to a second container containing material N. After identifying a second region of the first slice pattern, based on the pattern of the second region, an optical unit projects light into the second container containing material N, causing material N to cure to a curing depth of 100 μm, forming the second portion of the first layer. This results in a 50 μm overlap and a 50 μm non-overlapping region between the first and second portions of the first layer (along the construction direction of the first or second portion, or along the stacking direction of the slice layers).

[0180] After the second portion of the first layer is formed, the forming platform can carry the cured portion to a first container containing material M. A first slice image from a dataset of multiple slice images (100 in total) of the second portion, obtained based on a slice layer thickness of 100 μm, can be retrieved. After identifying a first region of the second slice image, based on the pattern of the first region, an optical unit projects light onto the first container containing material M, causing material M to cure to a curing depth of 100 μm, forming the first portion of the second layer. This results in a 50 μm overlap region and a 50 μm non-overlap region between the first portion and the second portion of the first layer (along the construction direction of the first or second portion, or along the stacking direction of the slice layers).

[0181] After forming the first portion of the second layer, the forming platform can carry the cured portion to a second container containing material N. After identifying the second region of the second slice pattern, based on the pattern of the second region, the optical unit projects light into the second container containing material N, causing material N to cure to a curing depth of 100 μm, forming the second portion of the second layer. This results in a 50 μm overlap area and a 50 μm non-overlap area between the first and second portions of the second layer (along the construction direction of the first or second portion, or along the stacking direction of the slice layers). Continuous printing using the above scheme yields the desired target object.

[0182] In some embodiments, when printing is performed, a first slice image from a plurality of slice images (e.g., 80) of the target object can be retrieved from a dataset. The first slice image is obtained based on a slice layer thickness of 60 μm. After identifying a first portion of the first slice image, an optical unit (e.g., a DMD component for DLP printing) projects light onto a first container containing material M based on the pattern of the first portion, so that material M is cured to form a first portion of the first layer at a curing depth (or curing thickness) of 60 μm.

[0183] After forming the first portion of the first layer, the forming platform can carry the cured portion to a second container containing material N. After identifying a second region of the first slice pattern, based on the pattern of the second region, an optical unit projects light into the second container containing material N, causing material N to cure to a curing depth of 60 μm, forming the second portion of the first layer. This results in a 60 μm overlap between the first portion and the second portion of the first layer (i.e., complete overlap) along the construction direction of either the first or second portion (or along the stacking direction of the slice layers). See, for example, the construction steps in Figures 5A-5C.

[0184] After the second portion of the first layer is formed, the forming platform can carry the cured portion to a first container containing material M. A second slice image from a dataset of multiple slice images (100 in total), obtained based on a slice layer thickness of 60 μm, can be retrieved. After identifying the first portion of the second slice image, based on the pattern of the first portion, an optical unit projects light onto the first container containing material M, causing material M to cure to a curing depth of 60 μm, forming the second layer of the first portion. This ensures that the second layer of the first portion and the second portion of the first layer do not overlap along the construction direction of the first or second portion (or along the stacking direction of the slice layers).

[0185] After the second layer of the first part is formed, the forming platform can carry the cured portion to a second container containing material N. After identifying the second part of the second slice pattern, based on the pattern of the second part, the optical unit projects light into the second container containing material N, causing material N to cure to a curing depth of 60 μm to form the second layer of the second part. This results in a 60 μm overlap area (i.e., complete overlap) between the second layer of the first part and the second layer of the second part along the construction direction of the first part or the second part (or along the stacking direction of the slice layers).

[0186] Because a single data model is sliced, the slicing parameters (especially the slice layer thickness) used for the first and second parts are the same. However, during the curing stage, the curing depth used for the first and second parts may be the same or different.

[0187] In one example, a target object with a thickness of 5000 μm is divided into 100 layers, each with a thickness of 50 μm, resulting in 100 slice images (numbered 1, 2, 3, ..., 100). In slice images numbered 1 to 20, the target object involves the formation of only one material M; in slice images numbered 21 to 60, the target object involves the formation of two materials M and N; and in slice images numbered 61 to 100, the target object involves the formation of two materials M, N, and P.

[0188] During printing, the process can begin by retrieving slice image number "1" from the dataset and printing it based on a curing thickness of 50 μm. Then, slice image number "2" is retrieved and printed based on a curing thickness of 100 μm, followed by slice image number "4" and printed based on a curing thickness of 100 μm; ...; then slice image number "18" is retrieved and printed based on a curing thickness of 100 μm, and finally slice image number "20" is retrieved and printed based on a curing thickness of 50 μm. In this example, the formation process involving only a single material M is completed.

[0189] The slice image numbered "21" was retrieved from the dataset and identified as including a first region related to material M and a second region related to material N. Based on the first region of the slice image, the optical unit cured material M with a curing thickness of 50 μm to form the first part of the first layer; then, based on the second region of the slice image, the optical unit cured material N with a curing thickness of 100 μm to form the second part of the first layer.

[0190] Subsequently, slice image number "23" was retrieved from the dataset, and it was identified that this slice image includes a first region related to material M and a second region related to material N. Based on the first region of the slice image, the optical unit cured material M with a curing thickness of 100 μm to form the second layer of the first part (which adheres to the first part of the first layer); then, based on the second region of the slice image, the optical unit cured material N with a curing thickness of 100 μm to form the second layer of the second part (which adheres to the second part of the first layer).

[0191] Subsequently, slice image number "25" was retrieved from the dataset, and it was identified that this slice image includes a first region related to material M and a second region related to material N. Based on the first region of the slice image, the optical unit cured material M with a curing thickness of 100 μm to form the third layer of the first part (which adheres to the second layer of the first part); then, based on the second region of the slice image, the optical unit cured material N with a curing thickness of 100 μm to form the third layer of the second part (which adheres to the second layer of the second part).

[0192] ......

[0193] The slice image numbered "59" was retrieved from the dataset and identified as including a first region associated with material M and a second region associated with material N. Based on the first region of the slice image, the optical unit cured material M to a curing thickness of 100 μm to form the twentieth layer of the first part (which adheres to the nineteenth layer of the first part); then, based on the second region of the slice image, the optical unit cured material N to a curing thickness of 100 μm to form the twentieth layer of the second part (which adheres to the nineteenth layer of the second part).

[0194] The slice image numbered "60" was retrieved from the dataset and identified as including a first region associated with material M and a second region associated with material N. Based on the first region of the slice image, the optical unit cured material M to a curing thickness of 50 μm to form the twenty-first layer of the first part (which adheres to the twentyth layer of the first part). In this exemplary manner, the formation involving materials M and N is completed.

[0195] Slice image numbered "61" was retrieved from the dataset and identified as including a first region related to material M, a second region related to material N, and a third region related to material P. Based on the first region of the slice image, the optical unit cured material M with a curing thickness of 50 μm to form the first portion of the first layer; then, based on the second region of the slice image, the optical unit cured material N with a curing thickness of 100 μm to form the second portion of the first layer; then, based on the third region of the slice image, the optical unit cured material P with a curing thickness of 150 μm to form the third portion of the first layer. Refer to Figures 6A-6C for the molding process.

[0196] Slice image number "64" was retrieved from the dataset and identified as including a first region related to material M, a second region related to material N, and a third region related to material P. Based on the first region of the slice image, the optical unit cured material M with a curing thickness of 150 μm to form the first part of the second layer (adhered to the first layer); then, based on the second region of the slice image, the optical unit cured material N with a curing thickness of 150 μm to form the second part of the second layer (adhered to the first layer); then, based on the third region of the slice image, the optical unit cured material P with a curing thickness of 150 μm to form the third part of the second layer (adhered to the first layer).

[0197] The slice image numbered "67" was retrieved from the dataset and identified as including a first region related to material M, a second region related to material N, and a third region related to material P. Based on the first region of the slice image, the optical unit cured material M with a curing thickness of 150 μm to form the first part of the third layer (adhered to the first part of the second layer); then, based on the second region of the slice image, the optical unit cured material N with a curing thickness of 150 μm to form the second part of the third layer (adhered to the second layer); then, based on the third region of the slice image, the optical unit cured material P with a curing thickness of 150 μm to form the third part of the third layer (adhered to the third layer).

[0198] ......

[0199] The slice image numbered "97" was retrieved from the dataset and identified as including a first region related to material M, a second region related to material N, and a third region related to material P. Based on the first region of the slice image, the optical unit cured material M with a curing thickness of 150 μm to form the first part of the thirteenth layer (adhered to the first part of the twelfth layer); then, based on the second region of the slice image, the optical unit cured material N with a curing thickness of 150 μm to form the second part of the thirteenth layer (adhered to the second part of the twelfth layer); then, based on the third region of the slice image, the optical unit cured material P with a curing thickness of 150 μm to form the third part of the thirteenth layer (adhered to the third part of the twelfth layer).

[0200] The slice image numbered "100" is retrieved from the dataset and identified as including a first region related to material M, a second region related to material N, and a third region related to material P. Based on the first region of the slice image, the optical unit cures material M with a curing thickness of 150 μm to form the first part of the fourteenth layer (adhered to the first part of the thirteenth layer); then, based on the second region of the slice image, the optical unit cures material N with a curing thickness of 100 μm to form the second part of the fourteenth layer (adhered to the second part of the thirteenth layer); then, based on the third region of the slice image, the optical unit cures material P with a curing thickness of 50 μm to form the third part of the fourteenth layer (adhered to the third part of the thirteenth layer). In this exemplary manner, the formation of materials M, N, and P is completed. Refer, for example, to the formation process in Figures 6H-6I.

[0201] Figures 13A-13C show cross-sectional views for two materials. As shown in Figures 13A-13C, the computer unit can identify a single cross-sectional view 1390 comprising a first region 1392 and a second region 1394, which are spaced apart. During printing, the first material is first cured according to the pattern (circle) of the first region 1392 (ideally as shown in Figure 13B), and then the second material, different from the first material, is cured according to the pattern (square) of the second region 1394 (ideally as shown in Figure 13C). In some embodiments, the curing depth for the first material is the same as the curing depth for the second material, for example, a curing depth of 40 μm. In some embodiments, the curing depth for the first material is different from the curing depth for the second material, for example, curing depths of 40 μm and 60 μm, respectively.

[0202] Figures 14A-14C show slice diagrams for two materials. As shown in Figures 14A-14C, the computer unit can identify a single slice diagram 1490 comprising a first region 1492 and a second region 1494, the first region 1492 and the second region 1494 having a partially common edge (as shown by the dashed line in Figure 14A). During printing, the first material is first cured according to the pattern (circle) of the first region 1492 (ideally as shown in Figure 14B), and then the second material, different from the first material, is cured according to the pattern (square with recesses) of the second region 1494 (ideally as shown in Figure 14C). In some embodiments, the curing depth for the first material is the same as the curing depth for the second material, for example, a curing depth of 40 μm. In some embodiments, the curing depth for the first material is different from the curing depth for the second material, for example, curing depths of 30 μm and 60 μm, respectively.

[0203] Figures 15A-15C show slice diagrams for two materials. As shown in Figures 15A-15C, the computer unit can identify a single slice diagram 1590 including a first region 1592 and a second region 1594, with an overlapping region 1593 (defined by the dashed line in Figure 15A). During printing, the first material is first cured according to the pattern (square) of the first region 1592 (ideally as shown in Figure 15B), and then the second material, different from the first material, is cured according to the pattern (square) of the second region 1594 (ideally as shown in Figure 15C). The area of ​​the overlapping region 1593 does not exceed 10% of the area of ​​either the first region 1592 or the second region 1594. In some embodiments, the curing depth for the first material is the same as the curing depth for the second material, for example, a curing depth of 40 μm. In some embodiments, the curing depth for the first material is different from the curing depth for the second material, for example, curing depths of 30 μm and 60 μm, respectively.

[0204] Those skilled in the art will understand that the computer unit can identify different parts of a single slice image, for example, different parts carrying identification information. Identification information includes at least one of the following: color, characters (numbers, letters, etc.), shape, annotations, etc. Identification information can be associated with corresponding parts of a single slice image at multiple stages.

[0205] For example, during the slicing stage, the target data model has been determined to include at least part 1 made of material M and part 2 made of material N. In the modeling software, parts 1 and 2 of the target data model have already been distinguished by corresponding explanatory information; for example, parts 1 and 2 are assigned different colors or annotations. As slicing progresses and the corresponding file format is converted, this explanatory information is retained or changed to corresponding distinguishing information. The computer unit can then identify and differentiate the two parts (corresponding to part 1 and part 2 respectively) in a single slice drawing based on this information.

[0206] During the slice image retrieval stage, when the retrieved single slice image does not contain information for distinguishing different sections, different parts or portions can be distinguished manually or automatically. For example, if the retrieved single slice image has two patterns spaced apart from each other, the first pattern can be selected as the first region of the slice image, and the second pattern can be selected as the second region of the slice image. In some embodiments, the first and second regions are automatically or manually identified because they are spaced apart from each other or partially define a common contour or have similar contour portions. It is understood that the different patterns identified or selected are assigned different information for subsequent alternating printing.

[0207] In some embodiments, at least one slice image from a first data model A (including a first portion) is acquired; at least one slice image from a second data model B (including a second portion), independent of the first data model A, is acquired. For example, based on the grayscale of slice image A1 of data model A and the grayscale of slice image B1 of data model B, the contours or patterns in slice image A1 and slice image B1 are merged into a single slice image C1, which has, for example, RGB channels, where the R channel is used to represent the contours or patterns in slice image A1 and the G channel is used to represent the contours or patterns in slice image B1. In slice image C1, the first portion corresponding to the pattern in slice image A1 and the second portion corresponding to the wheel pattern in slice image B1 may overlap, be spaced apart, or be tangent.

[0208] After acquiring the first slice image, the processor identifies a first region of the first slice image using first information, and identifies a second region of the first slice image using second information different from the first information. The first information and / or the second information includes at least one of the following: color, grayscale, character, and shape. During the generation of the first slice image or the acquisition of the first slice image, the first information is assigned to the first region of the first slice image, and the second information is assigned to the second region of the first slice image.

[0209] The use of slice diagrams illustrated in some embodiments herein allows for the acquisition of objects constructed from a variety of materials. Figure 16 shows a solid tooth comprising a gingiva (pink material) and a crown (white material) obtained by the additive manufacturing method of this application. This solid tooth is formed, for example, by at least one of the methods shown in Figures 11A-15C.

[0210] For example, print using image A of the gingival model first, and then print using image B of the crown model. Alternatively, print using the gingival region of slice C of the tooth model first, and then print using the crown region of slice C of the tooth model.

[0211] It's understandable that not all slice images obtained through slicing are used. For example, if the gingival model and the crown model each have 100 slice layers (or slice images) for dual-material printing, the first slice from the gingival model might be retrieved for printing; then the first slice from the crown model; then the third slice from the gingival model; and so on. This doesn't require using all 100 slice images.

[0212] During the printing process, this paper uses an alternating printing method, forming different parts of each layer sequentially. After all parts of one layer are formed, the next layer is printed.

[0213] Figures 17A-17C illustrate an ideal object composed of two materials. The cylindrical object 1740 shown in Figure 17A includes two ideal portions 1742 and 1744, which are in contact with each other along an ideal boundary 1050, as shown in the cross-sectional schematic diagram in Figure 17B. Those skilled in the art will understand that during photopolymerization printing, the material will shrink, creating a risk of a gap 1748 between the two actually formed portions.

[0214] Figures 18A-18D illustrate different embodiments of constructing objects using two materials. Figure 18A shows a first portion 1822 made of a first material A and a second portion 1824 made of a second material B, the first portion 1822 and the second portion 1824 contacting at a target interface 1150 and adhering to a molding platform 1810. The first portion 1822 and the second portion 1824 have the same thickness.

[0215] Figure 18B illustrates a first portion 1832 composed of a first material A and a second portion 1834 composed of a second material B. The first portion 1832 (formed based on an exposure of a first pattern) and the second portion 1834 (formed based on an exposure of a second pattern, wherein the first and second patterns are tangent or share edges) do not contact at the target interface 1850 as intended due to their respective material shrinkage rates. The first material A has a first shrinkage rate such that the side 18321 of the formed first portion 1832 near the target interface 1850 is at a first distance from the target interface 1850. The second material B has a second shrinkage rate such that the side 18341 of the formed second portion 1834 near the target interface 1850 is at a second distance from the target interface 1850. For example, the first shrinkage rate of the first material A is less than the second shrinkage rate of the second material B, such that the second distance is greater than the first distance. In some embodiments, the spacing between the side 18321 and the side 18341 due to the shrinkage rate is, for example, distributed between 1 μm and 30 μm.

[0216] Figure 18C shows a first portion 1842 made of a first material A and a second portion 1844 made of a second material B. The first material A has a first shrinkage rate such that the side 18421 of the first portion 1842, formed based on an applied first pattern exposure, is a first distance from the target interface 1850. To avoid gaps or gaps as shown in Figure 18B, exposure based on an enlarged second pattern (where the first and second patterns are tangent or share edges, and partially overlap) can be used to fill these gaps or gaps. As shown in Figure 18C, although the second material B has a second shrinkage rate, the side 18441 of the formed second portion 1844, near the target interface 1850, is a first distance from the target interface 1850, and the side 18441 of the second portion 1844 contacts or overlaps with the side 18421 of the first portion 1842. The interface 18421 or 18441 between the first portion 1842 and the second portion 1844 formed in this manner is spaced apart from the target interface 1850.

[0217] Figure 18D illustrates a first portion 1852 made of a first material A and a second portion 1854 made of a second material B. The first material A has a first shrinkage rate. The side 18521 of the first portion 1852, formed based on an enlarged first pattern exposure, is a first distance from the target interface 1850. The second portion 1854 is then formed based on a second pattern (the first and second patterns are tangent or share edges, and the enlarged first and second patterns partially overlap). The side 18541 of the second portion 1854, also a first distance from the target interface 1850 (because the second material B has a second shrinkage rate), is in contact with or overlaps with the side 18521 of the first portion 1852. The interface 18521 or 18541 between the first portion 1852 and the second portion 1854 formed in this manner is spaced apart from the target interface 1850. Understandably, once the first portion 1852 is formed based on the enlarged first pattern, the risk of a gap between the first portion 1852 and the second portion 1854 is reduced or eliminated, even if the second material B shrinks during curing. For example, the enlargement of the first pattern can be designed to completely avoid gaps. Alternatively or additionally, the second portion 1854 can also be formed based on an enlarged second pattern, building upon the formation of the first portion 1852 according to the enlarged first pattern. Understandably, when the first portion 1852 is formed based on the enlarged first pattern, and exposure is performed according to the second pattern (or even the enlarged second pattern), since the first portion 1852 already occupies a certain space (especially the portion surrounded by the side 18521 and the target interface 1850), the second material B will cure based on the interface or side 18521, thereby ensuring the elimination of gaps.

[0218] According to the embodiments shown in Figure 18C or Figure 18D, the area enclosed by the target interface 1850 and the actual interfaces 18421, 18441, 18521, 18541 is exposed twice, which poses a risk of overexposure. To reduce the risk of overexposure, different grayscale values ​​can be used to expose different areas when exposing based on the enlarged first pattern and / or the enlarged second pattern.

[0219] For example, if a first pattern is tangent to a second pattern (e.g., two tangent semicircles as shown in Figure 17B), and the enlarged first pattern partially overlaps with the second pattern, when exposing based on the enlarged first pattern, a reduced grayscale value (e.g., 128) can be assigned to the overlapping portion of the enlarged first and second patterns, while a normal grayscale value (e.g., 255) can be assigned to the remaining portion of the enlarged first pattern. Then, when exposing based on the second pattern, a reduced grayscale value (e.g., 128) can be assigned to the overlapping portion of the second pattern, while a normal grayscale value (e.g., 255) can be assigned to the remaining portion of the second pattern.

[0220] In another example, the first pattern is tangent to the second pattern (e.g., the two tangent semicircles shown in Figure 17B), and the first pattern partially overlaps with the enlarged second pattern. When exposing based on the first pattern, a normal grayscale value (e.g., 255) can be assigned to the first pattern. Then, when exposing based on the enlarged second pattern, a reduced grayscale value (e.g., 50) can be assigned to the overlapping portion of the enlarged second pattern and the first pattern, while a normal grayscale value (e.g., 255) can be assigned to the remaining portion of the enlarged second pattern.

[0221] In some embodiments, the length of the overlapping portion, along a direction perpendicular to the Z-axis (i.e., the construction direction), is determined based on the shrinkage rate of at least one of the first and second materials. It is understood that the shrinkage rates of the first and second materials may be the same or different. For example, the first and second materials may differ only in color.

[0222] Figures 19A-19D illustrate embodiments of constructing objects using two materials. Figure 19A shows a first portion 1922 made of a first material A and a second portion 1924 made of a second material B, which are in contact at a target interface 1950 and adhered to a molding platform 1910. The first portion 1922 and the second portion 1924 have different thicknesses. For example, the first portion 1922 has a thickness of 50 μm, and the second portion 1924 has a thickness of 80 μm.

[0223] Figure 19B illustrates a first portion 1932 composed of a first material A and a second portion 1934 composed of a second material B. The first portion 1932 (formed based on an exposure of a first pattern) and the second portion 1934 (formed based on an exposure of a second pattern, wherein the first and second patterns are tangent or share edges) do not contact at the target interface 1950 as intended due to their respective material shrinkage rates. The first material A has a first shrinkage rate such that the side 19321 of the formed first portion 1932 near the target interface 1950 is at a first distance from the target interface 1950. The second material B has a second shrinkage rate such that the side 19341 of the formed second portion 1934 near the target interface 1950 is at a second distance from the target interface 1950. For example, the first shrinkage rate of the first material A is less than the second shrinkage rate of the second material B, such that the second distance is greater than the first distance. In some embodiments, the spacing between the side 19321 and the side 19341 due to the shrinkage rate is, for example, distributed between 1 μm and 50 μm.

[0224] Figure 19C shows a first portion 1942 made of a first material A and a second portion 1944 made of a second material B. The first material A has a first shrinkage rate such that the side 19421 of the first portion 1942, formed based on an applied first pattern exposure, is at a first distance from the target interface 1950. To avoid gaps or gaps as shown in Figure 19B, exposure can be based on an enlarged second pattern (where the first and second patterns are tangent or share edges, and partially overlap) to fill or avoid gaps or gaps. As shown in Figure 19C, although the second material B has a second shrinkage rate, the side 19441 of the second portion 1944, formed based on an applied second pattern, is at a first distance from the target interface 1950, and the side 19441 of the second portion 1944 contacts or overlaps with the side 19421 of the first portion 1942. The interface 19421 or 19441 between the first part 1942 and the second part 1944 formed in this way is separated from the target interface 1950.

[0225] Figure 19D shows a first portion 1952 made of a first material A and a second portion 1954 made of a second material B. The first material A has a first shrinkage rate. The side 19521 of the first portion 1952, formed based on an enlarged first pattern exposure, is a first distance from the target interface 1950. Then, the second portion 1954 is formed based on a second pattern (the first pattern and the second pattern are tangent or share edges, and the enlarged first pattern partially overlaps with the second pattern). A portion of the side 19541 of the second portion 1954, which is near the target interface 1950, is a first distance from the target interface 1950 (because the second material B has a second shrinkage rate), and a portion of the side 19541 of the second portion 1954 contacts or overlaps with the side 19521 of the first portion 1952. A portion of the side 19541 of the second portion 1954 partially overlaps with the first portion 1952 in the horizontal direction (i.e., the direction perpendicular to the Z-axis). The interface 19521 between the first portion 1952 and the second portion 1954 formed in this manner is spaced apart from the target interface 1950. It is understood that when the first portion 1952 is formed based on the enlarged first pattern, the risk of a gap between the first portion 1952 and the second portion 1954 is reduced or eliminated, even if the second material B shrinks during curing. For example, the enlargement of the first pattern can be designed to completely avoid gaps. Alternatively or additionally, the second portion 1954 can also be formed based on an enlarged second pattern, based on the formation of the first portion 1952 according to the enlarged first pattern. It is understood that when the first portion 1952 is formed according to the enlarged first pattern, and exposure is performed according to the second pattern (or even the enlarged second pattern), since the first portion 1952 already occupies a certain space (especially the portion surrounded by the side 19521 and the target interface 1950), the second material B will cure based on the interface or side 19521, thereby ensuring the elimination of gaps.

[0226] Figure 19D shows that the second part 1954 formed by the enlarged second pattern includes a discontinuous side near the target interface 1950, which in one part coincides with or contacts the side 19521 of the first part 1952, and in another part does not contact the first part 1952.

[0227] Figures 20A-20C illustrate some embodiments of actual boundaries. In the embodiment shown in Figure 20A, the first portion 2032 and the second portion 2034 of the object are intended to contact at the target interface (or boundary line) 2050; however, the formed first portion 2032 and the second portion 2034 actually contact at the predetermined interface (or boundary line) 2060. Along the target interface 2050, the spacing between the predetermined interface and the target interface varies. This spacing is, for example, within the range of 0 to 100 μm; for instance, the spacing between the predetermined interface and the target interface in one part is 0 to 50 μm; the spacing between the predetermined interface and the target interface in another part is 20 μm to 60 μm.

[0228] In the embodiment shown in Figure 20B, the first portion 2042 and the second portion 2044 of the object are intended to contact at the target interface (or boundary line) 2050; however, the formed first portion 2042 and the second portion 2044 actually contact at the trapezoidal predetermined interface (or boundary line) 2070. In the embodiment shown in Figure 20C, the first portion 2052 and the second portion 2054 of the object are intended to contact at the target interface (or boundary line) 2050; however, the formed first portion 2052 and the second portion 2054 actually only contact at the two ends 2082, 2084, while a gap appears in the middle region 2086 (due to shrinkage). Since this gap cannot be directly perceived by, for example, the human eye, this is acceptable in some scenarios.

[0229] In some embodiments, the target object comprises at least two target layers, which are adhered together. Figures 21A-21G illustrate embodiments of a target object comprising at least two target layers.

[0230] As shown in Figures 21A-21B, in the two target layers (each target layer includes two parts that come into contact with each other, and the two parts are made of different materials), the predetermined interface is always located on one side of the target interfaces 2151 and 2152, or in other words, the actual interface is located on one side of the ideal interfaces 2151 and 2152. More specifically, when forming each target layer, the interface between the two different parts determined based on the slice diagram is the target interface or the ideal interface. After applying, for example, the strategy shown in Figures 18A-19D, the interface between the two different parts actually formed is the predetermined interface or the actual interface.

[0231] As shown in Figures 21C-21D, in two target layers (each target layer comprising two parts in contact with each other, the two parts being composed of different materials), predetermined interfaces are distributed on both sides of target interfaces 2153 and 2154. In the first target layer formed earlier, the predetermined interface is distributed on one side of target interface 2153 or target interface 2154. In the second target layer formed later, the predetermined interface is distributed on the other side of target interface 2153 or target interface 2154. It is understood that the spacing (or average spacing) between the target interface and the predetermined interface can be different in each target layer. For example, in the first target layer, the spacing (or average spacing) between target interfaces 2153 and 2154 and the predetermined interface is 235 μm, while in the second target layer, the spacing (or average spacing) between target interfaces 2153 and 2154 and the predetermined interface is 150 μm.

[0232] As shown in Figures 21E-21F, in two target layers (each target layer comprising two parts in contact with each other, the two parts being made of different materials), a portion of the predetermined interface is located on one side of target interface 2155 or target interface 2156. In the first target layer formed earlier, at least a portion of the predetermined interface is located on one side of target interface 2155 or target interface 2156. In the second target layer formed later, at least a portion of the predetermined interface is located on one side of target interface 2155 or target interface 2156.

[0233] As shown in Figure 21G, in the two target layers (each target layer includes two parts that are in contact with each other, and the two parts are made of different materials), the predetermined interface is distributed on both sides of the target interface 2157. In the first target layer formed first, a portion of the predetermined interface is distributed on one side of the target interface 2157. In the second target layer formed later, the predetermined interface is distributed on both sides of the target interface 2157. In the third target layer, only a single material is formed.

[0234] Figure 22 illustrates an embodiment for forming an object comprising two materials. As shown in Figure 22, the object 2200 comprises multiple layers. Material A is exposed and cured to form a first portion 2211 of a first layer 2210 of the object 2200, the first portion 2211 containing only material A. Material B is exposed and cured to form a second portion 2212 of the first layer 2210 of the object 2200, the second portion 2212 containing only material B and formed on the first portion 2211. Material A is exposed and cured to form a first portion 2221 of a second layer 2220 of the object 2200, the first portion 2221 containing only material A. Material B is exposed and cured to form a second portion 2222 of the second layer 2220 of the object 2200, the second portion 2222 containing only material B and formed on the first portion 2221. Material A is exposed and cured to form a first portion 2231 of a third layer 2230 of the object 2200, the first portion 2231 containing only material A. Material B is exposed and cured to form a second portion 2232 of the third layer 2230 of object 2200, the second portion 2232 containing only material B and formed on the first portion 2231. Material A is exposed and cured to form a fourth layer 2240 of object 2200, the fourth layer containing only a single material A.

[0235] Figures 23A-23D illustrate embodiments of constructing objects using two materials. In the embodiment shown in Figure 23A, a plurality of layers formed of material A are adhered to a molding platform 2310, each layer having a thickness of, for example, 50 μm. A support device 2320 carries material A, and the bottom surface of the molding platform 2310 (or, the cured portion thereof) is, for example, 50 μm away from the support device 2320 to facilitate subsequent curing of material A to form a 50 μm thick layer 2381. Figure 23A also shows the molding platform 2310 after the formation of layer 2381 has been lifted.

[0236] As shown in Figure 23B, based on commands from the control system, the molding platform 2310 moves to align with the support device 2340. Then, based on the positioning parameters previously set at the support device 2320, the molding platform 2310 stops at a position 50 μm from the bottom surface 2322 of the support device 2320, with the desired curing material B to obtain a 50 μm thick cured layer 2382 (indicated by the dashed line). However, the bottom surface 2342 of the support device 2340 is not at the same height as the bottom surface 2322 of the support device 2320, which is attributed, for example, to installation errors of the support devices 2340 and 2320.

[0237] Based on the height position shown in Figure 23B, exposure according to the previously applied exposure process parameters (e.g., parameters for a 50μm thick layer for curing material A, or parameters for a 50μm thick layer for curing material B) will result in layer 2382 not adhering to the cured layer 2381, as shown in Figure 23C. This will cause layer 2382 to remain in the carrier device 2340 instead of being carried away by the subsequently lifted forming platform 2310, which is detrimental to the subsequent printing process. The layer 2382, indicated by the dashed line in Figure 23C, has a thickness of 50μm, and the distance D between layer 2382 and layer 2381 is approximately equal to the vertical distance between the bottom surface 2342 of carrier device 2340 and the bottom surface 2322 of carrier device 2320. For example, distance D is 2μm, 5μm, 10μm, or 20μm. Distance D is affected by the installation errors of carrier devices 2340 and 2320.

[0238] As shown in Figure 23D, the layer 2382 composed of material B has an increased thickness (70 μm), which makes the formed layer 2382 bond to the cured layer 2381.

[0239] To increase the curing depth or thickness of layer 2382, exposure can be enhanced. For example, the luminous power of the optical unit can be increased, or the exposure time can be extended (intermittently or continuously). Specifically, in terms of process parameter design, the curing thickness can be increased directly by adjusting the values ​​of luminous power and / or exposure time. Alternatively or additionally, in terms of process flow design, at least two exposures based on the pattern of layer 882 can be performed to increase the curing thickness.

[0240] Those skilled in the art will understand that, because the layer 2382 to be cured will adhere to the cured layer 2381, even if the theoretical cured thickness based on enhanced exposure parameters is large, the actual cured thickness will be limited by the vertical distance difference between the bottom surface of the support device and the expected cured thickness. For example, if the vertical distance difference between the bottom surface of the support device is 20 μm and the expected cured thickness (the pre-designed thickness of layer 2382) is 50 μm, even if the theoretical cured thickness after enhancing exposure parameters reaches 80 μm (or even 100 μm), the actual cured thickness will not reach 80 μm or 100 μm, but will be at most 70 μm. This is because the cured layer 2381 occupies space and thus hinders the unlimited expansion of layer 2382.

[0241] In some embodiments, if the bottom surface 2342 of the support device 2340 is higher than the bottom surface 2322 of the support device 2320, and the molding platform 2310 moves from the support device 2320 to the support device 2340 along the expected path, then the distance between the bottom surface of the molding platform 2310 (or the cured layer 2381 it carries) and the support device 2340 will be less than the expected layer thickness. For example, if the cured layer 2381 has a thickness of 50 μm, the expected thickness of the cured layer 2382 is 50 μm, and the bottom surface 2342 of the support device 2340 is 20 μm higher than the bottom surface 2322 of the support device 2320, then the actual thickness of the formed layer 2382 is 30 μm. Even if the exposure parameters are adjusted to increase the curing depth, the actual thickness of the layer 2382 will only be 30 μm and will not continue to increase because it is limited by the cured layer 2381.

[0242] Those skilled in the art will understand that using different support devices at different planes or heights carries the aforementioned risk of non-bonding. For example, if support device M is installed at location A, and support device N is installed at a different location B, installation errors may cause support device M and support device N to be at different heights (e.g., a vertical distance of 2 μm). Support device M and support device N may contain the same but different materials. For example, support device M may contain material S1, and support device N may contain material S2, which is different from material S1. Alternatively, both support device M and support device N may contain material S1.

[0243] Figures 24-26 show schematic diagrams of slicing an object formed using two materials. As shown in Figure 24, the object includes a first part 2451 composed of material A and a second part 2452 composed of material B. The object is sliced ​​according to slicing planes 2411, 2412, 2413, 2414, and 2415, where the spacing between adjacent pairs of slicing planes 2411, 2412, 2413, 2414, and 2415 may be the same or different. Those skilled in the art will understand that the slice images obtained based on slicing planes 2411, 2412, and 2413 only contain the portion related to material A, and the slice images obtained based on slicing planes 2414 and 2415 only contain the portion related to material B. After the slice image obtained based on slicing plane 2413 is used to cure material A, the slice image obtained based on slicing plane 2414 will be used to cure material B. At this time, the forming platform needs to be moved from a first support device carrying material A to a second support device carrying material B, and the exposure parameters can be adjusted to increase the curing depth. When the processing unit identifies that the most recently used slice image is related to material A, and the most recently used slice image is related to material B (different from material A), the processing unit can automatically adjust the exposure parameters to increase the curing depth.

[0244] As shown in Figure 25, the object comprises a first part 2561 composed of material A, a second part 2562 composed of material A, and a third part 2563 composed of material B. The object is sliced ​​according to slicing planes 2521, 2522, 2523, 2524, and 2525, where the spacing between adjacent pairs of slicing planes 2521, 2522, 2523, 2524, and 2525 may be the same or different. Those skilled in the art will understand that the slice diagrams obtained based on slicing planes 2521, 2522, and 2523 only contain the portion related to material A, while the slice diagrams obtained based on slicing planes 2524 and 2525 contain both the portion related to material A and the portion related to material B. After the slice diagram obtained based on slicing plane 2523 is used to cure material A, the slice diagram obtained based on slicing plane 2524 will be used to cure both material A and material B (e.g., first curing material A based on a portion of the slice diagram, then curing material B based on another portion of the slice diagram). At this stage, the molding platform can be moved from the first support device carrying material A to the second support device carrying material B, and the exposure parameters can be adjusted to increase the curing depth. When the processing unit recognizes that the most recently used slice image is related to material A, and the most recently used slice image is related to material B (different from material A) and material A, the processing unit can automatically adjust the exposure parameters to increase the curing depth.

[0245] As shown in Figure 26, the object comprises a first part 2671 composed of material A, a second part 2672 composed of material B, a third part 2673 composed of material A, and a fourth part 2674 composed of material B. The object is sliced ​​at least according to slicing planes 2631, 2632, 2633, 2634, and 2635, where the spacing between adjacent pairs of slicing planes 2631, 2632, 2633, 2634, and 2635 may be the same or different. Those skilled in the art will understand that the slice images obtained according to slicing planes 2631, 2632, and 2633 include portions related to material A and portions related to material B, and the slice images obtained according to slicing planes 2634 and 2635 include portions related to material A and portions related to material B. When the slice image obtained based on slicing plane 2631 is used to cure materials A and B, the molding platform can be moved from a first support device carrying material A to a second support device carrying material B, and the exposure parameters can be adjusted to increase the curing depth. When the processing unit identifies that the most recently used slice image (e.g., a slice image obtained based on slice plane 2631) is related to material A, and the most recently used slice image (e.g., a slice image obtained based on slice plane 2631) is related to both material B and material A, the processing unit can automatically adjust the exposure parameters to increase the curing depth, thereby ensuring that the cured portion adheres to or is on the molding platform. Similarly, when a slice image obtained based on slice plane 2634 is used to cure materials A and B, the molding platform can be moved from a first support device carrying material A to a second support device carrying material B, and the exposure parameters can be adjusted to increase the curing depth. When the processing unit identifies that the most recently used slice image (e.g., a slice image obtained based on slice plane 2634) is related to material A, and the most recently used slice image (e.g., a slice image obtained based on slice plane 2634) is related to both material B and material A, the processing unit can automatically adjust the exposure parameters to increase the curing depth.

[0246] Figures 27A-27D illustrate schematic diagrams of forming an object using two materials. As shown in Figure 27A, the additive manufacturing system includes a forming platform 2720 for adhering and curing the object and a container 2740 containing material A. The container 2740 has a membrane 2742 that is at least partially transparent, such as an FEP membrane, PFA membrane, ACF membrane, etc. An optical unit (not shown) projects light rays that pass through the membrane 2742 from below and cure material A in the container 2740. Those skilled in the art will understand that the membrane 2742 actually has an uneven surface; for example, the membrane 2742 defines a reference line or reference plane 2744, and the membrane may have portions above and below the reference plane 2744. For example, the highest point of the membrane may be 80 μm higher or lower than the reference plane 2744.

[0247] As shown in Figure 27B, the forming platform 2720 descends to a position h away from the reference plane 2744 of the membrane 2742 in the container 2740. If the process parameters (e.g., exposure parameters) are set according to the maximum cured thickness h, there is a risk of plate dropping. In other words, if the process parameters are set to allow a layer of thickness h to be formed, the layer 2781 to be formed will theoretically have a flat upper surface (i.e., the surface near the forming platform) and a lower surface (i.e., the surface near the membrane), and a thickness h. However, since the membrane has an uneven surface, the lower surface of the layer 2781 to be formed is also uneven, and the upper surface is also uneven due to incomplete curing. If the process parameters are set to allow a layer of thickness h*150% to be formed, then the layer 2781 to be formed will have a flat upper surface and an uneven lower surface 27812, as shown in Figure 27B. It can be understood that the lower surface 27812 of layer 2781 has a consistent profile with at least a portion of the membrane 2742.

[0248] As shown in Figure 27C, the forming platform 2720 of the additive manufacturing system moves to a position aligned with a container 2760, which contains material B (different from material A). The container 2760 has a membrane 2762 that is at least partially transparent. Those skilled in the art will understand that the membrane 2762 actually has an uneven surface; for example, the membrane 2762 defines a reference line or reference plane 2764, and the membrane may have portions above and below the reference plane 2764. For example, the highest point of the membrane 2762 may be 70 μm higher or lower than the reference plane 2764. The forming platform 2720 moves to a position such that the forming surface of the forming platform 2720 (or the upper surface of layer 2781) is 2h away from the reference plane 2764 of the container 2760, or the theoretical lower surface of layer 2781 (which is uneven) is h away from the reference plane 2764 of the container 2760.

[0249] As shown in Figure 27D, a layer 2781 composed of material A is adhered to the molding platform 2720, and a layer 2782 composed of material B is partially adhered to layer 2781. The lower surface 27822 of layer 2782 at least partially conforms to the contour of film 2762 because material B is cured on film 2762 and subsequently peeled off. The upper surface 27823 of layer 2782 at least partially conforms to the contour of the lower surface 27812 of layer 2781 because material B is also cured on the lower surface 27812 of layer 2781 and adheres to it.

[0250] Both the upper surface 27823 of layer 2782 and the membrane 2762 are uneven on the micrometer (μm) scale, thus the formed layer 2782 has uneven upper and lower surfaces. The distance between the highest and lowest points of layer 2782 along the Z-axis, the stacking direction of the layers, or the construction direction of the object may be, for example, greater than 1.5h. It is understood that the contours of membrane 2742 of container 2740 and membrane 2762 of container 2760 are different on the micrometer (μm) scale, which makes the distance between the highest point of the lower surface 27812 of layer 2781 along the Z-axis and the reference plane 2764 of membrane 2762 potentially greater than h, for example, 1.3h. Furthermore, points on membrane 2762 (corresponding to the highest point of the lower surface 27812 of layer 2781) may be lower than the reference plane 2764, for example, lower by 0.3h. If the process parameters are set to allow a layer with a maximum thickness of h*150%, the cured thickness of material B will not allow layer 2782 to fully adhere to layer 2781. To ensure that layer 2782 adheres to layer 2781, the process parameters should be adjusted to increase the curing depth. For example, the process parameters can be set to allow a layer with a maximum thickness of h*190%.

[0251] As an example, in Figures 27A-27D, the first layer 2781 has a thickness of 100 μm. The actual surface of the film 2742 in container 2740 deviates from its reference plane 2744 by ±40 μm. Exposure is performed using a first exposure parameter that allows a maximum curing depth of 150 μm, resulting in a first layer 2781 with a thickness of 100 μm and composed of material A (with an uneven lower surface). The forming platform then moves toward container 2760 to prepare for curing a second layer with a thickness of 100 μm. The actual surface of the film 2762 in container 2760 deviates from its reference plane 2764 by ±60 μm. Exposure is performed using a second exposure parameter that allows a maximum curing depth of 200 μm, resulting in a second layer 2782 with a thickness of 100 μm and composed of material B (with an uneven lower surface).

[0252] The maximum curing depth allowed by the first exposure parameter can be 1.3 to 1.8 times the thickness of the layer to be cured, for example, 1.4, 1.5, 1.6, or 1.7 times. The maximum curing depth allowed by the second exposure parameter can be 1.5 to 2.5 times the thickness of the layer to be cured, for example, 1.6, 1.7, 1.8, or 1.9 times, or even 2.0, 2.1, 2.2, 2.3, or 2.4 times.

[0253] When constructing an object using only a single material (e.g., A or B), a constant exposure parameter can be used to cure the material. This constant exposure parameter allows a maximum cure depth, for example, 1.3 to 1.8 times the thickness of the layer to be cured. When switching from one material (e.g., A) to another material (e.g., B) to construct an object, the exposure parameter for the specified material (e.g., B) needs to be adjusted to allow a greater maximum cure depth. For example, the maximum cure depth allowed by the exposure parameter when always using only material B to construct an object is D. The maximum cure depth allowed by the exposure parameter when switching from material A to material B is 1.1D to 2.5D, such as 1.2D, 1.3D, 1.4D, 1.5D, 1.6D, 1.7D, 1.8D, 1.9D, 2.0D, 2.1D, 2.2D, 2.3D, and 2.4D.

[0254] For example, the thickness of each layer formed using material B is 50 μm. In this case, the maximum curing depth allowed by the exposure parameters for constructing the object using only material B is, for example, 80 μm to 140 μm, 90 μm to 130 μm, or 100 μm to 120 μm.

[0255] For example, each layer formed using material B has a thickness of 50 μm. In this case, the maximum curing depth allowed by the exposure parameters when switching from material A to material B to construct the object is, for example, 90 μm to 180 μm, 100 μm to 170 μm, 110 μm to 160 μm, 120 μm to 150 μm, or 130 μm to 140 μm.

[0256] For example, each layer formed using material B has a thickness of 100 μm. In this case, the maximum curing depth allowed by the exposure parameters for constructing an object using only material B is, for example, 120 μm to 250 μm, 130 μm to 240 μm, 140 μm to 230 μm, 150 μm to 220 μm, 160 μm to 210 μm, 170 μm to 200 μm, and 180 μm to 190 μm.

[0257] For example, each layer formed using material B has a thickness of 100 μm. In this case, the maximum curing depth allowed by the exposure parameters when switching from material A to material B to construct the object is, for example, 120 μm to 300 μm, 130 μm to 290 μm, 140 μm to 280 μm, 150 μm to 270 μm, 160 μm to 260 μm, 170 μm to 250 μm, 180 μm to 240 μm, 190 μm to 230 μm, 200 μm to 220 μm, or 210 μm.

[0258] For example, the thickness of each layer formed using material B is 150 μm. In this case, the maximum curing depth allowed by the exposure parameters for constructing the object using only material B is, for example, 180 μm to 320 μm, 190 μm to 310 μm, 200 μm to 300 μm, 210 μm to 290 μm, 220 μm to 280 μm, 230 μm to 270 μm, 240 μm to 260 μm, or 250 μm.

[0259] For example, the thickness of each layer formed using material B is 150 μm. In this case, the maximum curing depth allowed by the exposure parameters when switching from material A to material B to construct the object is, for example, 200 μm–380 μm, 210 μm–370 μm, 220 μm–360 μm, 230 μm–350 μm, 240 μm–340 μm, 250 μm–330 μm, 260 μm–320 μm, 270 μm–310 μm, 280 μm–320 μm, 290 μm–310 μm, or 300 μm.

[0260] In one embodiment, material A is used to construct the first layer of the object, then material B is used to construct the second layer of the object (formed on the first layer), and then material B is used to construct the third layer of the object (formed on the second layer). The maximum curing depth allowed by the exposure parameters used when forming the third layer can be less than the maximum curing depth allowed by the exposure parameters used when forming the second layer, to avoid overexposure when forming the third layer. For example, the thicknesses of the first, second, and third layers are all 100 μm, the maximum curing thickness used to form the first layer is 160 μm, the maximum curing thickness used to form the second layer is 210 μm, and the maximum curing thickness used to form the third layer is 160 μm.

[0261] In some embodiments, a rigid transparent or translucent device, such as glass, is disposed beneath the membrane 2742 of container 2740 or the membrane 2762 of container 2760. Light emitted by the optical unit passes through the glass and the membrane to solidify the material.

[0262] The terms "curing depth" and "curing thickness" refer to the thickness of a solidified object formed from a liquid or paste under different conditions (e.g., different exposure conditions). For example, resin material is placed in a container with a liquid level of 3000 μm. An optical unit projects light or exposes the material in the container according to a predetermined pattern, so that the light intensity at the film in the container is 30 W / m². 2 The exposure time is 2 seconds, causing a cured object to form on the film of the container. The cross-section of the cured object is a predetermined pattern, and the thickness of the cured object is the cured thickness or cured depth. For example, material A is detected under light intensity of 30 W / m². 2The thickness is 80 μm at an exposure time of 2 seconds. At this time, the "curing depth" is 80 μm, and the "maximum curing depth" is also 80 μm (because the formation of the upper surface of the cured object is not limited by other objects). Similarly, material A is used again at a light intensity of 30 W / m². 2 The thickness is 100μm when the exposure time is 3s. At this time, the "curing depth" is 100μm and the "maximum curing depth" is also 100μm (because the formation of the upper surface of the cured object is not limited by other objects).

[0263] The various components or elements in the embodiments shown herein can be combined with each other without causing contradiction. Embodiments obtained through such combinations also fall within the scope of this document.

[0264] The description in this application is merely exemplary in nature, and therefore, variations intended without departing from the essence of this application are within its scope. Such variations should not be considered as departing from the spirit and scope of this application.

Claims

1. A method for forming a target object by additive manufacturing, the target object comprising a first portion made of a first material and a second portion made of a second material different from the first material, the method comprising: Obtain multiple slice images of the first part and multiple slice images of the second part; Using the first slice of multiple slices in the first part, and radiating the first printing area to solidify the first material and form the first part of the first layer of the target object; Using the first slice from multiple slices in the second part, and irradiating the second printing area to cure the second material and form the second part of the first layer of the target object, Along the construction direction of the target object, the first part of the first layer and the second part of the first layer at least partially overlap.

2. The method according to any one of the preceding claims, wherein obtaining multiple slice images of the first portion and multiple slice images of the second portion comprises: At least the data model of the first part of the target object is obtained, and the data model of the first part is sliced ​​to obtain multiple slice images of the first part; and At least the data model of the second part of the target object is obtained, and the data model of the second part is sliced ​​to obtain multiple slice images of the second part.

3. The method according to any one of the preceding claims, wherein obtaining the plurality of slice images of the first part and the plurality of slice images of the second part further comprises: Obtain the data model of the target object, and then separate the data model of the target object to obtain the first part of the data model and the second part of the data model.

4. The method according to any one of the preceding claims, wherein obtaining the plurality of slice images of the first part and the plurality of slice images of the second part further comprises: Obtain multiple slice images of the first part from the first dataset, and obtain multiple slice images of the second part from the second dataset.

5. The method according to any one of the preceding claims further comprises: Using a second slice from multiple slices of the first portion, the first printed area is radiated to cure the first material to form the first portion of the second layer; and Using the second slice from multiple slices of the second part, the second printed area is irradiated to cure the second material to form the second part of the second layer. Wherein, along the construction direction of the target object, the first part of the second layer and the second part of the second layer at least partially overlap.

6. The method according to any one of the preceding claims, wherein, In the multiple slice images of the first part, there is at least one slice image between the first slice image and the second slice image.

7. The method according to any of the preceding claims, wherein, Multiple slice images from the first part and multiple slice images from the second part were obtained based on the same slice layer thickness.

8. The method of any of the preceding claims, wherein, The first part comprises multiple slice images including an initial slice image, multiple intermediate slice images, and an end slice image; the second part comprises multiple slice images including an initial slice image, multiple intermediate slice images, and an end slice image; wherein the cured thickness associated with at least one intermediate slice image of the first part is equal to the cured thickness associated with at least one intermediate slice image of the second part.

9. A method for forming a target object by additive manufacturing, the target object comprising a target segment, the target segment comprising a first portion made of a first material and a second portion made of a second material different from the first material, the method comprising: Obtain the first slice image for the target segment; Based on the first region of the first slice image, the first printing region is radiated to solidify the first material to form the first part of the first layer of the target segment; Based on the second region of the first slice image, the second printing area is radiated to solidify the second material to form the second part of the first layer.

10. The method according to any one of claims 1-9, wherein, Along the construction direction of the target object, the first part of the first layer and the second part of the first layer at least partially overlap; or Along the construction direction of the target object, the first part of the first layer is tangent to the second part of the first layer.

11. The method according to any one of claims 1-10, wherein obtaining the first slice image for the target segment comprises: Obtain a single data model containing the target segment, and slice the single data model to generate a first slice map for the target segment.

12. The method according to any one of claims 1-11, wherein obtaining the first slice image for the target segment comprises: Obtain at least one slice of a first data model, wherein the first data model includes a first part of the target segment; Obtain at least one slice of a second data model independent of the first data model, wherein the second data model includes a second portion of the target segment; The first slice is generated based on at least one slice of the first data model and at least one slice of the second data model.

13. The method according to any one of claims 1-12, wherein generating the first slice based on at least one slice based on the first data model and at least one slice based on the second data model comprises: - Generate the first slice image associated with RGB information based on the grayscale information of at least one slice image of the first data model and the grayscale information of at least one slice image of the second data model; and / or - Generate the first slice based on the size information of at least one slice from the first data model and the size information of at least one slice from the second data model, so that the first region is separated from the second region.

14. The method of any one of claims 1-13, wherein, The first region and the second region of the first slice image are configured in any of the following ways: - Separated; -Having a partially shared edge; or - Has overlapping areas.

15. The method according to any one of claims 1-14, further comprising: After obtaining the first slice image, the first region of the first slice image is identified by the first information, and the second region of the first slice image is identified by the second information that is different from the first information, wherein the first information or the second information includes at least one of the following: color, grayscale, character, shape.

16. The method according to any one of claims 1-15, further comprising: Obtain the second slice image for the target section; Based on the first region of the second slice image, the first printing area is radiated to solidify the first material to form the first part of the second layer; The second printing area is irradiated based on the first region of the second slice image to cure the second material and form the second part of the second layer. Wherein, along the construction direction, the first part of the second layer and the second part of the second layer at least partially overlap.

17. The method according to any one of claims 1-16, wherein the target object further comprises a base portion located upstream or downstream of the first layer along the construction direction of the target object, wherein the base portion is selected from any one of the following: Composed of the first material; Composed of a second material; or It is composed of a third material, which is different from both the first and second materials.

18. The method according to any one of claims 1-17, wherein a first portion of the first layer has a first thickness, and a second portion of the first layer has a second thickness greater than the first thickness.

19. The method according to any one of claims 1-18, wherein the first thickness is 1%-99% of the second thickness, for example 30%-70%, for example 40%-60%, for example 50%.

20. The method according to any one of claims 1-19, wherein the second thickness is 5 μm to 300 μm, for example 20 μm to 200 μm, for example 50 μm to 150 μm, for example 75 μm to 125 μm.

21. The method according to any one of claims 1-20, further comprising: (i) A first portion of a second layer is formed on a first portion of a first layer, such that the total thickness of the first portion made of the first material is greater than the total thickness of the second portion made of the second material; (ii) A second portion of the second layer is formed on the second portion of the first layer, such that the total thickness of the second portion made of the second material is greater than the total thickness of the first portion made of the first material; ...... (iii) Form the first part of the (n+1)th layer on the first part of the nth layer, such that the total thickness of the first part made of the first material is greater than the total thickness of the second part made of the second material, n≥3; (iv) Form a second part of the (n+1)th layer on the second part of the nth layer, such that the total thickness of the second part made of the second material is greater than the total thickness of the first part made of the first material.

22. The method according to any one of claims 1-21, wherein the data model of the first part of the target object and the data model of the second part of the target object are in contact at a target interface, and the actually formed first part and second part are in contact at a predetermined interface, wherein the predetermined interface and the target interface are at least partially spaced apart along a predetermined direction perpendicular to the construction direction.

23. A method for forming a target object by additive manufacturing, the target object comprising a target layer, the target layer including a first target portion and a second target portion contacting at a target interface, the method comprising: Light is projected onto the first carrier device through an optical unit to solidify the first material carried by the first carrier device and form the first solidified portion of the target layer of the target object; Light is projected onto the second carrier device through an optical unit to solidify the second material carried by the second carrier device, forming a second solidified portion of the target layer of the target object. The second material is different from the first material. The first cured portion and the second cured portion contact at a predetermined interface, and Along a predetermined direction perpendicular to the construction direction of the target object, the predetermined interface and the target interface are at least partially spaced apart.

24. The method according to any one of claims 1-23, wherein, Along the predetermined direction, the predetermined interface and the target interface are spaced at least 10 μm to 1000 μm apart.

25. The method according to any one of claims 1-24, wherein, Along the predetermined direction, the predetermined interface and the target interface are spaced at least 100 μm to 500 μm apart.

26. The method according to any one of claims 1-25, wherein, The regions projected along the construction direction by the first target portion and the second target portion are equal to or substantially equal to the regions projected along the construction direction by the first cured portion and the second cured portion.

27. The method according to any one of claims 1-26, wherein, The optical unit projects light based on a first pattern to form a first cured portion, and projects light based on a second pattern to form a second cured portion, wherein the first pattern and the second pattern have overlapping portions.

28. The method according to any one of claims 1-27, wherein, The grayscale value assigned to the overlapping portion of the first pattern is less than the grayscale value assigned to the remaining portion of the first pattern; or The grayscale value of the overlapping portion of the second pattern is less than the grayscale value of the remaining portion of the second pattern.

29. The method according to any one of claims 1-28, wherein, The width of the overlapping portion along a predetermined direction is determined based on the number of pixels, where the number of pixels is 1 to 10.

30. The method according to any one of claims 1-29, wherein, Along the construction direction, a portion of the predetermined interface is any of the following: straight, wavy, or serrated.

31. The method according to any one of claims 1-30, wherein, The first thickness of the first cured portion is equal to the second thickness of the second cured portion.

32. The method according to any one of claims 1-31, wherein, The first cured portion has a first thickness, and the second cured portion has a second thickness, wherein the first thickness is 1% to 99% of the second thickness, for example, 30% to 70%, 40% to 60%, or 50%.

33. The method according to any one of claims 1-32, wherein, The first thickness of the first cured portion is 5μm to 200μm, for example 20μm to 180μm, for example 50μm to 150μm, for example 75 to 125μm.

34. The method according to any one of claims 1-33, wherein the first cured portion and the second cured portion partially overlap along the predetermined direction.

35. The method according to any one of claims 1-34, wherein the target layer further comprises a third target portion, the third target portion contacting the second target portion at the second target interface, the method further comprising: Light is projected onto the third carrier device through an optical unit to solidify the third material carried by the third carrier device, forming the third solidified portion of the target layer of the target object. This third material is different from the second material. The third cured portion and the second cured portion contact each other at the second predetermined interface, and Along a predetermined direction perpendicular to the Z-axis, the second predetermined interface and the second target interface are at least partially spaced apart.

36. The method according to any one of claims 1-35, wherein the target object comprises at least two target layers, the at least two target layers being adhered together.

37. The method according to any one of claims 1-36, wherein the length of the overlapping portion along the predetermined direction is determined based on the shrinkage rate of at least one of the first material and the second material.

38. A three-dimensional printing method for forming a target object through radiation, comprising: A first slice image for first curing is identified as being associated with a first material, and the first slice image is assigned first exposure parameters; A second slice image for second curing is identified as being associated with a second material, the first material being different from the second material, and the second slice image being assigned a second exposure parameter; The first curing includes: irradiating a first material to form a first part of the target object based on a first slice image and first exposure parameters; After the first curing, a second curing process is performed; The second curing includes irradiating a second material to form a second portion of the target object based on a second slice image and modified second exposure parameters, wherein the modified second exposure parameters are configured to increase the curing depth.

39. The method according to any one of claims 1-38, wherein identifying the association between the first slice image for the first curing and the first material comprises: The first slice image was identified as including only the portion associated with the cured first material. or The first slice image is identified as including: a first portion associated with the first material and a second portion associated with a material different from the first material.

40. The method according to any one of claims 1-39, wherein identifying the association between the second slice image for the second curing and the second material comprises: The second slice image was identified as including only the portion associated with the cured second material. or The second slice image is identified as including: a first portion associated with the second material, and a second portion associated with a material that has been cured differently from the second material.

41. The method according to any one of claims 1-40, wherein the changed second exposure parameter comprises: Increased exposure power or extended exposure time, at least one of these.

42. The method according to any one of claims 1-41, wherein performing a second curing after the first curing comprises: The second curing process is performed immediately after the first curing.

43. The method according to any one of claims 1-42, further comprising: Provides a first support device for carrying a first material and a second support device for carrying a second material; Determine the distance between the bottom surface of the first support device and the bottom surface of the second support device along the construction direction of the target object; and Based on the distance, the changed second exposure parameter is determined.

44. The method according to any one of claims 1-43, wherein the second part of the target object is formed on the first part of the target object along the construction direction of the target object.

45. The method according to any one of claims 1-44, wherein along the construction direction of the target object, the second part of the target object at least partially overlaps with the first part of the target object.

46. ​​The method according to any one of claims 1-45, wherein the thickness of the second portion is greater than the thickness of the first portion.

47. The method according to any one of claims 1-46, further comprising: The first material is irradiated to form a third part of the target object on the first part, such that the total thickness of all parts composed of the first material is greater than the total thickness of all parts composed of the second material. Then, The second material is irradiated to form a fourth part of the target object on the second part, such that the total thickness of all parts composed of the second material is greater than the total thickness of all parts composed of the first material.

48. The method according to any one of claims 1-47, wherein the maximum curing depth corresponding to the changed second exposure parameter is 1.1 to 2.5 times, preferably 1.2 to 1.8 times, the maximum curing depth corresponding to the second exposure parameter.

49. A storage medium comprising a program configured to perform the method of any one of claims 1-48.

Images