阅读说明：本技术 三维打印方法和设备 (Three-dimensional printing method and apparatus ) 是由 侯锋 于 2019-05-05 设计创作，主要内容包括：本发明涉及一种三维打印方法和设备,包括获取用于承载打印模型的承载台的孔分布；曝光所述打印模型从面向所述承载台的底面起的至少一层,其中削弱或省略所述孔分布所指示的孔区域的曝光。本发明根据三维打印设备中的承载台上的孔分布对打印模型的切片图像进行处理,控制孔分布所对应的孔区域的曝光程度,使打印模型的底部平整,利于精度和美观。(The invention relates to a three-dimensional printing method and equipment, which comprises the steps of obtaining hole distribution of a bearing table for bearing a printing model; exposing at least one layer of the printing model from a bottom surface facing the carrier table, wherein exposure of the area of the holes indicated by the hole distribution is attenuated or omitted. According to the invention, the slice image of the printing model is processed according to the hole distribution on the bearing table in the three-dimensional printing equipment, and the exposure degree of the hole area corresponding to the hole distribution is controlled, so that the bottom of the printing model is flat, and the precision and the attractiveness are facilitated.)

1. A three-dimensional printing method comprising the steps of:

acquiring hole distribution of a bearing table for bearing a printing model;

exposing at least one layer of the printing model from a bottom surface facing the carrier table, wherein exposure of the area of the holes indicated by the hole distribution is attenuated or omitted.

2. The three-dimensional printing method of claim 1, wherein the step of exposing at least one layer of the print model from a bottom surface facing the stage comprises:

processing at least one layer of slice images of a data model of the printing model from the bottom surface according to the hole distribution of the bearing table, and weakening or omitting pixels of hole areas indicated by the hole distribution in the at least one layer of slice images;

and performing exposure by using the processed at least one layer of slice image.

3. The three-dimensional printing method of claim 1, wherein for a first portion of the plurality of layers of the print model from the bottom surface facing the stage, the exposure of the aperture region is omitted; attenuating exposure of the aperture region for a second partial layer of the plurality of layers of the printing model from the bottom surface facing the carrier, wherein the second partial layer is located above the first partial layer.

4. The three-dimensional printing method of claim 3, wherein the printing model is a layer on top of the second partial layer, fully exposed in the aperture region.

5. The three-dimensional printing method according to claim 3 or 4, wherein the pore region of the first partial layer is cured by the superimposed exposure of the second partial layer and the layer above the second partial layer.

6. The three-dimensional printing method according to claim 1, wherein each layer of the printing model has a thickness of 0.05-0.3 mm.

7. The three-dimensional printing method of claim 1, wherein the size of the holes is 2-5 mm.

8. The three-dimensional printing method according to claim 1 or 3, wherein the number of the at least one layer or the first or second partial layer is 2-5 layers.

9. The three-dimensional printing method of claim 1, wherein the method prints using a photo-curing process.

10. A three-dimensional printing apparatus adapted to print a three-dimensional model, the three-dimensional printing apparatus comprising a printing mechanism and a controller configured to control the printing mechanism to perform the method of any of claims 1-9.

11. A computer-readable medium having stored thereon computer program code which, when executed by a processor, implements the method of any of claims 1-9.

Technical Field

The invention relates to a three-dimensional printing technology, in particular to a three-dimensional printing method and equipment for directly printing a three-dimensional model under the condition of no support on a bearing platform with holes.

Background

The three-dimensional printing technology is characterized in that a computer three-dimensional design model is used as a blueprint, special materials such as metal powder, ceramic powder, plastics, cell tissues and the like are stacked layer by layer and bonded through a software layering dispersion and numerical control forming system in a laser beam mode, a hot melting nozzle mode and the like, and finally, an entity product is manufactured through superposition forming. The forming mode of the three-dimensional printing technology is continuously evolving, and among various forming modes, the photocuring method is a mature mode. The light curing method is to use the principle that light curing materials are cured after being irradiated by ultraviolet light to perform material accumulation molding, and has the characteristics of high molding precision, good surface smoothness, high material utilization rate and the like.

Fig. 1 is a basic structure of a photocuring-type three-dimensional printing apparatus. This three-dimensional printing apparatus 100 includes a material tank 110 for containing a photosensitive resin, a stage 120 for carrying a molded workpiece, a coating blade 130 for spreading the photosensitive resin, an image exposure system 140 for curing the photosensitive resin, and a control system 150 for controlling the actions of the stage 120, the coating blade 130, and the image exposure system 140. The image exposure system 140 is located above the material tank 110 and irradiates a beam image to cure a layer of photosensitive resin on the liquid surface of the material tank 110. After the image exposure system 140 irradiates a beam image to cure a layer of photosensitive resin, the carrier 120 slightly lowers the layer of cured photosensitive resin, and the coating scraper 130 moves to uniformly spread the photosensitive resin on the top surface of the cured workpiece for the next irradiation. And circulating the steps, and obtaining the three-dimensional workpiece formed by layer-by-layer accumulation.

The workpiece is typically manually removed after it has been printed. When small articles (such as tooth models) are printed, the printing process can be completed in a short time, and if a manual method is still adopted to remove the workpiece, the printing efficiency of the three-dimensional model is reduced, and continuous automatic printing of the three-dimensional printing equipment cannot be realized. In order to solve this problem, some solutions adopt a method of distributing a plurality of holes 121 on the carrier table 120 and arranging a jacking device 160 below the carrier table 120, as shown in fig. 1. The jacking device 160 has a plurality of jacking rods 161 corresponding to the plurality of holes 121 on the carrier table 120. After the printing of the workpiece is finished, the three-dimensional printing device can control the jacking device 160 to be matched with the plurality of holes 121, so that the plurality of ejector rods 161 on the jacking device 160 are inserted into the plurality of holes 121 on the bearing table 120 to eject the workpiece, thereby realizing the automatic separation of the workpiece and the bearing table 120, and enabling the three-dimensional printing device to automatically enter the next printing task.

However, this solution brings new problems. Due to the holes 121 on the carrier 120, the holes 121 on the surface of the carrier 120 are filled with the photosensitive resin. When the image exposure system 140 irradiates a beam image, a portion of the photosensitive resin in the hole 121 is cured due to the penetration of light, so that a few small downward protrusions are formed in the cured layer. These small projections can cause the bottom of the printed workpiece to be uneven, and since these projections are not controlled by the printing system, and belong to the mistakenly increased Z-axis (height direction) height, the precision of the product in the Z-axis can be seriously affected, and the appearance is also not good.

Disclosure of Invention

The invention aims to provide a three-dimensional printing method and equipment, which can enable the bottom of a printing model to be flat.

The invention adopts the technical scheme to solve the technical problems that the three-dimensional printing method comprises the following steps: acquiring hole distribution of a bearing table for bearing a printing model; exposing at least one layer of the printing model from a bottom surface facing the carrier table, wherein exposure of the area of the holes indicated by the hole distribution is attenuated or omitted.

Optionally, the step of exposing at least one layer of the printing model from the bottom surface facing the stage comprises: processing at least one layer of slice images of a data model of the printing model from the bottom surface according to the hole distribution of the bearing table, and weakening or omitting pixels of hole areas indicated by the hole distribution in the at least one layer of slice images; and performing exposure by using the processed at least one layer of slice image.

Optionally, for a first partial layer of the plurality of layers of the printing model from the bottom surface facing the bearing platform, omitting exposure of the hole region; attenuating exposure of the aperture region for a second partial layer of the plurality of layers of the printing model from the bottom surface facing the carrier, wherein the second partial layer is located above the first partial layer.

Optionally, the printing model is located on a layer above the second partial layer, fully exposed in the area of the aperture.

Optionally, the pore region of the first partial layer is cured by a superimposed exposure of the second partial layer and the layer above the second partial layer.

Optionally, each layer of the printing form has a thickness of 0.05-0.3 mm.

Optionally, the size of the aperture is 2-5 mm.

Optionally, the number of the at least one layer or the first or second partial layer is 2-5 layers.

Alternatively, the method prints using a photo-curing method.

The present invention further provides a three-dimensional printing apparatus adapted to print a three-dimensional model, the three-dimensional printing apparatus including a printing mechanism and a controller configured to control the printing mechanism to perform the method as described above.

The solution adopted by the present invention to solve the above technical problem also includes a computer readable medium storing computer program code, which when executed by a processor implements the method as described above.

The three-dimensional printing method and the three-dimensional printing equipment have the advantages that the slice image of the printing model is processed according to the hole distribution on the bearing table in the three-dimensional printing equipment, the exposure degree of the hole area corresponding to the hole distribution is controlled, the bottom of the printing model is flat, and the printing precision and the attractiveness are improved.

Drawings

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below, wherein:

fig. 1 is a basic structure of a photo-curing type three-dimensional printing apparatus;

fig. 2 is a schematic top view of a plummer of a three-dimensional printing apparatus according to an embodiment of the present invention;

FIG. 3 is a schematic perspective view of a printing mechanism of a three-dimensional printing device according to an embodiment of the invention;

FIG. 4 is an exemplary flow diagram of a three-dimensional printing method according to an embodiment of the invention;

fig. 5A-5C are schematic diagrams of an exemplary exposure process in a three-dimensional printing method according to an embodiment of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described herein, and thus the present invention is not limited to the specific embodiments disclosed below.

As used in this application and the appended claims, the terms "a," "an," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that steps and elements are included which are explicitly identified, that the steps and elements do not form an exclusive list, and that a method or apparatus may include other steps or elements.

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

Fig. 2 is a schematic top view of a stage 120 of a three-dimensional printing apparatus according to an embodiment of the invention. Referring to fig. 2, a plurality of holes 121 are distributed on the surface of the carrier table 120, and the holes 121 penetrate through the bottom of the carrier table 120, and can be used for cooperating with the jacking device 160 shown in fig. 1 to automatically separate the three-dimensional model from the surface of the carrier table 120 after the three-dimensional model is printed. The location, size, number and distribution of the holes 121 are not limited to those shown in fig. 2.

In some embodiments, the surface of the carrier 120 of the three-dimensional printing apparatus of the present invention may also be distributed with a plurality of concave portions 122 recessed downward. The recesses 122 do not extend through the carrier 120, but rather have a depth. These recessed portions 122 may be due to defects formed during the manufacturing of the carrier 120, or may be generated by the carrier 120 due to various artificial or objective reasons, such as object falling, during the use of the three-dimensional printing apparatus.

In some embodiments, there may be both a plurality of holes 121 and a plurality of recesses 122 on the carrier table 120.

As shown in fig. 2, a coating blade 130 for spreading a photosensitive resin is disposed above the carrier table 120. The coating blade 130 is generally located at one end of the stage 120 when the three-dimensional printing apparatus is in a stopped state or an initial state. When the three-dimensional printing apparatus starts to operate, the coating blade 130 moves in parallel from one end of the stage 120 to the other end of the stage 120. The coating blade 130 may spread a layer of photosensitive resin uniformly on the surface of the carrier 120. The image exposure system 140 irradiates the layer of photosensitive resin to cure portions of the photosensitive resin corresponding to the beam pattern, thereby completing printing of a layer of the three-dimensional model. The carrier 120 drives the cured layer to move downward for a certain distance, the coating scraper 120 then moves back to one end of the carrier 120 from the other end of the carrier 120 in parallel, and a layer of photosensitive resin is uniformly spread on the surface of the carrier 120 again for the next illumination.

It is understood that when the surface of the carrier table 120 has the holes 121 or the recesses 122, the photosensitive resin spread by the coating blade 130 fills the holes 121 and the recesses 122. When the image exposure system 140 irradiates a beam image, a part or all of the photosensitive resin in the holes 121 and the recesses 122 is cured due to the penetration of light, so that corresponding small protrusions are formed in the cured layer. The Z-axis precision of the three-dimensional model depends on the distance from the lowest point of the bottom surface of the model to the highest point of the model, and the precision of the three-dimensional model in the Z-axis direction is reduced due to the bulge on the bottom surface of the model.

Fig. 3 is a schematic perspective view of a printing mechanism of a three-dimensional printing apparatus according to an embodiment of the present invention. The printing mechanism includes, but is not limited to, a stage 120, a coating blade 130, an image exposure system 140 (not shown), and the like. Referring to fig. 3, a coating blade 130 is slidably disposed on the carrier 120 for spreading a layer of photosensitive resin on the surface of the carrier 120. In some embodiments, the coating blade 130 is also used to scrape the mold off the carrier 120 after it has been printed. The susceptor 120 has a plurality of holes 121 or recesses 122 on its surface. The image exposure system 140 is located above the carrier 120 and the coating scraper 130, and is spaced apart from the carrier 120, and is configured to irradiate the photosensitive resin laid on the surface of the carrier 120 according to each slice image in the data model of the printing model, so as to cure a portion corresponding to the slice image, thereby obtaining one layer in the printing model.

In some embodiments, the printing mechanism of the three-dimensional printing apparatus may further include a carriage, a photosensitive resin storage device, a temperature control device, and the like.

It will be appreciated that the three-dimensional printing apparatus of the present invention includes, in addition to the printing mechanism shown in fig. 3, a controller or processor for controlling the printing mechanism to perform the entire process of printing the print mode.

Fig. 4 is an exemplary flowchart of a three-dimensional printing method according to an embodiment of the present invention. Referring to fig. 4, the three-dimensional printing method of the present embodiment includes the steps of:

in step 410, the hole distribution of the carrier 120 is obtained. In this step, the hole distribution of the carrier 120 for carrying the printing model can be obtained by, but not limited to, the following ways: 1. before the three-dimensional printing equipment is started, an external photographic device is used for shooting a picture of the bearing table 120, and an image or data containing hole distribution information is obtained; 2. arranging a photographic device on the three-dimensional printing equipment, and after the three-dimensional printing equipment is started, controlling the photographic device to shoot a picture of the bearing table 120 by the controller according to a user instruction to acquire an image or data containing hole distribution information; 3. a photographing device or a photographing function can be arranged on the image exposure system 140, and after the three-dimensional printing equipment is started, the image exposure system 140 is used for photographing the bearing platform 120 to obtain an image or data containing hole distribution information; 4. the information of the hole distribution is obtained according to the design drawing of the carrier table 120.

It is understood that the hole distribution on the carrier 120 can also be expressed in the form of data, and is not limited to the form of images. The format of the data may be a two-dimensional array, a three-dimensional matrix, or the like.

The purpose of this step is to make the controller or processor of the three-dimensional printing apparatus obtain the hole area indicated by the hole distribution of the stage 120. The image or data information containing the pore distribution may be transmitted to a controller or processor of the three-dimensional printing device via a memory, a network, or the like. The memory means may be a memory device containing image or data information of the pore distribution transmitted through a memory interface on a controller or processor of the three-dimensional printing device. For example, a memory card of a camera is directly inserted into a computer main body as a controller of the three-dimensional printing apparatus. The network may include a wired network, a wireless network, bluetooth, etc. to transmit the image or data information containing the hole distribution to the controller or processor of the three-dimensional printing apparatus. For example, the network function of the camera is used to directly transmit the photos to the host computer as the controller of the three-dimensional printing device through bluetooth.

In some embodiments, the distribution of holes on the carrier table 120 obtained in this step is all the distribution of holes on the entire carrier table 120.

In some embodiments, the hole distribution on the carrier 120 obtained in this step may include several pieces of information corresponding to each layer of slice image or data in a specific printing model. For example, each slice image or data layer has a hole distribution information, which includes the hole area on the carrier 120 in the slice image or data layer that needs to be illuminated. Specifically, the hole distribution information of the portion of the slice image that needs to be illuminated can be obtained by performing a logical and operation on each element of the slice image data and the corresponding element of the matrix with the hole distribution information.

At step 420, at least one layer of the printing model from the bottom surface facing the bearing table 120 is exposed. Wherein the exposure of the hole areas indicated by the hole distribution is attenuated or omitted. In this step, the coating blade 130 has laid down a layer of photosensitive resin on the surface of the carrier 120 for photocuring printing of the layer of the pattern. In addition to illuminating the layer of photosensitive resin with a predetermined exposure image, the image exposure system 140 attenuates or omits exposure of the corresponding hole regions based on the information obtained from the hole distribution obtained in step 410.

Further, step 420 includes the steps of:

at step 421, at least one slice image of the data model of the print model from the bottom surface is processed according to the hole distribution of the carrier 120. Pixels of the hole region indicated by the hole distribution are attenuated or omitted in at least one slice image.

When three-dimensional model printing is performed, a controller of a three-dimensional printing apparatus stores in advance a data model of a model to be printed, the data model corresponding to a multi-layer slice image of the print model. In some embodiments, the three-dimensional printing device prints upward from the bottom of the print model. During the printing process, when the image exposure system 140 irradiates a layer of photosensitive resin on the carrier 120, the layer of photosensitive resin is irradiated according to a layer of slice image of the bottom surface of the printing mold, so as to form a layer of mold at the bottom of the printing mold. After the layer of pattern is cured, the carrier 120 is moved downward, and the coating blade 130 re-lays a layer of photosensitive resin on the bottom of the carrier 120 for printing of the next layer of pattern from the bottom of the print pattern, at which time the image exposure system 140 correspondingly illuminates the layer of photosensitive resin according to the second layer of sliced image from the bottom of the print pattern. And by analogy, exposing and curing layer by layer from the bottom surface to the top surface of the printing model, and completing the three-dimensional printing of the whole printing model.

In this step, considering the holes 121 or recesses 122 on the stage 120, the image exposure system 140 first processes a slice image of a print model when exposing the slice image, and weakens or omits the pixels in the hole area in the slice image according to the hole area indicated by the hole distribution obtained in step 410. The weakening corresponds to a reduction in the intensity of the irradiation light to the hole region, and the omission corresponds to no irradiation of the hole region. The number of layers of pixels that need to omit the holes 121 or recesses 122 may be determined in consideration of the penetration depth of light of the image exposure system 140.

In some embodiments, a scheme of omitting the pixels of the holes 121 or the recesses 122 may be employed for printing at least one layer of the slice image at the bottom of the model. For example, assuming that the degree of layering of a photosensitive resin layer used for printing a three-dimensional model is d, the depth through which light can penetrate is 3 d. Ideally, in the two-layer slice image from the lowest layer of the print model, the pixels of the holes 121 or the recesses 122 are omitted. When printing the slice image of the third layer from the bottommost layer of the printing model, without special treatment on the slice image of the third layer, light can penetrate through the thickness of the three layers of photosensitive resins, so that the three layers of photosensitive resins are all cured, and no protrusion is generated at the position of the hole 121 or the concave part 122. In some cases, since the penetration depth of light is not strictly limited to an integral multiple of the photosensitive resin layer thickness d, even about an integral multiple of the photosensitive resin layer thickness d, for example, 3d, in order to ensure that no protrusion is formed at the bottom of the three-dimensional model, in a slice image of more than two layers from the lowest layer of the printed model, the pixels of the hole 121 or the depression 122 may be omitted. For example, processing of omitting the pixels of the holes 121 or the recesses 122 is performed on three-layer slice images from the lowermost layer of the print model. When the fourth layer of slice image from the bottommost layer of the printing model is printed, the slice image of the layer is not specially processed. Light can penetrate through the thickness of the three layers of photosensitive resin to cure the three layers of photosensitive resin. Light may also be applied to the fourth layer of photosensitive resin on the lowermost layer to fully cure or partially cure that portion of the photosensitive resin. Under the condition that the part of the photosensitive resin is completely cured, the bottom of the obtained three-dimensional model is flat; when the portion of the photosensitive resin is partially cured, the bottom of the resulting three-dimensional model has some depressions. Because the Z-axis precision of the three-dimensional model depends on the distance from the lowest point of the bottom surface of the model to the highest point of the model, the Z-axis precision cannot be influenced by the depression of the bottom surface of the model. Of course, the depth of the depression can be made as small as possible by adjustment.

In some embodiments, a pixel-weakening scheme is employed in at least one slice image. This scheme can attenuate the intensity of light striking the aperture 121 or recess 122 by adjusting the intensity distribution of light produced by the image exposure system 140. The intensity of the light determines the penetration depth of the light in the photosensitive resin. In this case, the number of the at least one layer is related to the degree of light attenuation and the penetration depth in the hole 121 or the recess 122. Assuming that the depth of the hole 121 or the recess 122 is d, the light penetration depth at the time of full exposure is 3 d. When printing a slice image of the bottommost layer of the stamp pattern, the pixels of the aperture region are attenuated, i.e. the intensity of the light corresponding to the aperture region is attenuated, so that the penetration depth of the light is d. Ideally, a flat bottom surface of the mold is obtained. However, in practical cases, the light may penetrate to a depth greater than d, or small bumps may form on the bottom of the mold. Thus, the degree of weakening of the pixels in the hole area may be greater. When the weakening of the hole area pixels is so great that when printing a slice image of the bottommost layer of the stamp pattern, the solidified thickness of the corresponding hole area is less than the layer thickness d, a depression is formed in the bottom of the pattern. Because the Z-axis precision of the three-dimensional model depends on the distance from the lowest point of the bottom surface of the model to the highest point of the model, the Z-axis precision cannot be influenced by the depression of the bottom surface of the model. Of course, the depth of the depression can be made as small as possible by adjustment.

In some embodiments, the size of the area in which the pixels are to be thinned out or omitted in the three-dimensional model slice image may be suitably larger than the size of the aperture area, so long as the layer of cured model can be stably adhered to the stage 120.

In some embodiments, the multi-layered slice image of the print model from the bottom surface facing the stage 120 is divided into a first partial layer, a second partial layer, and other layers in order from the bottom up. Wherein the first partial layer comprises at least one layer of slice images from the bottommost portion of the print model; a second partial layer located over the second partial layer and including at least one slice image immediately above an uppermost one of the first partial layers; the other layer is located above the second partial layer and includes at least one slice image immediately above an uppermost layer of the second partial layer. In the three-dimensional printing method, for the first part layer in the printing model, the exposure of the corresponding hole area is omitted; weakening the exposure of the corresponding hole area of the second partial layer in the printing model; and completely exposing the corresponding hole areas of other layers in the printing model.

In these embodiments, due to the light transmission property, when exposing the second partial layer, the light will transmit to the first partial layer; when exposing other layers, light can penetrate the second partial layer and/or the first partial layer.

In some embodiments, the pore region of the first partial layer is cured by a superimposed exposure of the second partial layer and the further layers.

In practical applications, the number of layers of the first partial layer and the second partial layer can be determined by experiments. For example, a model finished product in which three-dimensional printing has been completed is inspected, and if the bottom of the model finished product has a protrusion, the number of layers of the first partial layer is increased; if the bottom of the model finished product is provided with a recess, and the depth of the recess exceeds the layer thickness d, reducing the layer number of the first part of layers; if the bottom of the finished model has a depression, the depth of which is less than the layer thickness d, the light intensity of the corresponding hole region of the second partial layer is further attenuated. And repeating the test for many times until the bottom of the model finished product is flat. Of course, in consideration of the adjustment difficulty and the working efficiency, the bottom of the model finished product is allowed to have a little recess, and the Z-axis precision of the model is not influenced.

In some embodiments, the at least one layer is 2-5 layers in number.

In some embodiments, the printed model is a dental model.

It should be noted that, in this step, weakening or omitting the exposure of the hole region indicated by the hole distribution means weakening or omitting the hole region located in the portion of the slice image of the layer where illumination is required. Exposure is not required for the hole region located in the portion of the slice image where illumination is not required.

In some embodiments, the distribution of holes on the carrier table 120 acquired in step 410 is all of the distribution of holes on the entire carrier table 120. In these embodiments, the controller of the three-dimensional printing apparatus may further include comparing the slice image of the layer with the hole distribution before controlling the pixels of the hole area indicated by the hole distribution to be attenuated or omitted in the slice image of the at least one layer, and only the holes 121 or the recesses 122 in the slice image of the layer where the exposure is required are processed, and the holes 121 or the recesses 122 located outside the exposure-required portion are not required to be processed.

In other embodiments, the hole pattern obtained in step 410 on the carrier 120 already includes information corresponding to each slice image or data in a particular printing model, and there is no need to compare the slice image with the hole pattern in this step.

And step 422, exposing by using the processed at least one layer of slice image. It can be understood that the three-dimensional printing method of the present invention can make the bottom surface of the printing model flat, and after the exposure of the at least one layer of slice image (the first partial layer and the second partial layer) is finished, the exposure can be directly performed without processing the rest of slice images (i.e. other layers).

It should be noted that, after the hole distribution information of the carrier 120 is obtained in step 410, the controller or the processor of the three-dimensional printing apparatus of the present invention establishes a corresponding relationship between the projection of the image exposure system 140 and the hole distribution, and makes the projection hole of the image exposure system 140 and the hole on the carrier 120 coincide with each other by adjusting some parameters, such as the X-axis position, the X-axis magnification, the Y-axis position, the Y-axis magnification, the image rotation angle, and the like. In practice, the projected aperture is allowed to be 10-20% larger than the aperture in the carrier 120 for process feasibility reasons, and subsequent exposures will fill in these unexposed areas due to light transmission. Moreover, since the carrier 120 is generally made of high-reflection material such as aluminum, stainless steel, etc., the exposure light from the rear is irradiated onto the carrier 120 and reflected back to the material to further solidify the material, thereby ensuring the bonding strength between the model and the carrier 120.

Fig. 5A-5C are schematic diagrams of an exemplary exposure process in a three-dimensional printing method according to an embodiment of the present invention. In this embodiment, the carrier 120 has a plurality of holes 121. Assuming that a layer of the liquid photosensitive resin has a thickness d, in some embodiments, the thickness d is 0.05-0.3 mm. The thickness of the carrier 120 is D and the depth of the hole 121 is equal to the thickness of the carrier 120, which is also D. In some embodiments, the aperture 121 has a one-dimensional dimension of 2-5 mm. When the hole is a circular hole as shown in the drawing, the one-dimensional size is the diameter of the hole. When the aperture is of other shape, for example rectangular, the one-dimensional dimension is the length or width of the rectangle.

Referring to fig. 5A, a first layer of liquid photosensitive resin is laid on the carrier table 120. It will be appreciated that the first layer of liquid photosensitive resin fills the plurality of apertures 121 in the carrier 120. When a conventional three-dimensional printing method is adopted, the image exposure system 140 directly irradiates the first layer of liquid photosensitive resin on the bearing table 120, and the light transmission depth is certainly greater than d due to consideration of the bonding strength between the model layers, and at this time, a part of the liquid photosensitive resin in the holes 121 is also cured, which forms small protrusions on the bottom surface of the printing model, and since the protrusions are not controlled by the printing system and belong to the mistakenly increased Z-axis height, the Z-axis (height direction) precision of the product is seriously affected, and the practicability and the attractiveness are also affected.

The arrows in FIG. 5A pointing toward the surface of the stage 120 represent light emitted from the image exposure system 140 according to the slice image of the print model. According to the three-dimensional printing method of the present invention, the controller of the three-dimensional printing apparatus controls the image exposure system 140, processes the slice image, omits pixels of the hole regions included in the slice image, and irradiates light only to the portions other than the holes 121 to cure the liquid photosensitive resin at these portions. It should be noted that the liquid photosensitive resin in the hole 121 is not irradiated with light and thus remains in a liquid state. The layer exposure is completed to form a first cured layer 510. Fig. 5A shows a side view of the carrier table 120. if viewed from the top, the first cured layer 510 may be integrally connected, rather than discretely distributed as shown.

After the exposure step shown in fig. 5A, the first layer of liquid photosensitive resin is cured except for the locations of the holes 121, the stage 120 is moved downward, and the coating blade 130 lays a second layer of liquid photosensitive resin on the surface of the stage 120. Referring to fig. 5B, the second layer of liquid photosensitive resin overlies the first layer of cured resin 510. A second layer of liquid photosensitive resin also fills the holes 121 before illumination is applied. In fig. 5B, the controller of the three-dimensional printing apparatus controls the image exposure system 140, processes the slice image, omits pixels of the hole regions included in the slice image, and irradiates light only to the portions other than the holes 121 to cure the liquid photosensitive resin in these portions. Thereby, the second cured layer 520 is formed on the first cured layer 510.

After the exposure step shown in fig. 5B, the liquid photosensitive resin except for the portions of the holes 121 is cured, the stage 120 is moved downward, and the coating blade 130 lays a third layer of the liquid photosensitive resin on the surface of the stage 120. Referring to fig. 5C, the third layer of liquid photosensitive resin overlies the second cured layer 520. The third layer of liquid photosensitive resin also fills the holes 121 before illumination is applied. In fig. 5C, the controller of the three-dimensional printing apparatus controls the image exposure system 140, processes the layer of the sliced image to weaken pixels of the hole regions included in the layer of the sliced image, and forms a third cured layer 530 on the second cured layer 520 by exposing the third layer of the liquid photosensitive resin using the processed sliced image. In the exposure step shown in fig. 5C, the degree to which the pixels corresponding to the positions of the holes 121 are attenuated in the processed slice image depends on the penetration depth of the corresponding light. In this step, the third cured layer 530 has a thickness d at a portion outside the hole 121. The light irradiated into the hole 121 is controlled in a pixel weakening mode to enable the curing depth of the liquid photosensitive resin to be less than or equal to 3d, and therefore the accuracy of the three-dimensional model printed by the three-dimensional printing device in the Z-axis direction can be guaranteed. Ideally, the light irradiated into the hole 121 is controlled such that the curing depth of the portion of the liquid photosensitive resin is equal to 3d, and the three-dimensional model can have a flat bottom surface. In the embodiment illustrated in fig. 5A-5C, the slice images of the print model corresponding to the first cured layer 510 and the second cured layer 520 correspond to a first partial layer and the slice image of the print model corresponding to the third cured layer 530 corresponds to a second partial layer.

In the above description we neglect possible further penetration of the second partial layer by other layers, and if any, the strength of the second partial layer can be weakened on the basis of an analysis of the slice image of the print model to ensure that there are no bumps on the bottom of the print.

The order of processing elements and sequences, the use of alphanumeric characters, or other designations in the present application is not intended to limit the order of the processes and methods in the present application, unless otherwise specified in the claims. While various presently contemplated embodiments of the invention have been discussed in the foregoing disclosure by way of example, it is to be understood that such detail is solely for that purpose and that the appended claims are not limited to the disclosed embodiments, but, on the contrary, are intended to cover all modifications and equivalent arrangements that are within the spirit and scope of the embodiments herein.

This application uses specific words to describe embodiments of the application. Reference throughout this specification to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic described in connection with at least one embodiment of the present application is included in at least one embodiment of the present application. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, some features, structures, or characteristics of one or more embodiments of the present application may be combined as appropriate.

Aspects of the methods and apparatus of the present application may be performed entirely by hardware, entirely by software (including firmware, resident software, micro-code, etc.), or by a combination of hardware and software. The above hardware or software may be referred to as "data block," module, "" engine, "" unit, "" component, "or" system. The processor may be one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), digital signal processing devices (DAPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or a combination thereof. Furthermore, aspects of the present application may be represented as a computer product, including computer readable program code, embodied in one or more computer readable media. For example, computer-readable media can include but are not limited to magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips … …), optical disks (e.g., Compact Disk (CD), Digital Versatile Disk (DVD) … …), smart cards, and flash memory devices (e.g., card, stick, key drive … …).

The computer readable medium may comprise a propagated data signal with the computer program code embodied therein, for example, on a baseband or as part of a carrier wave. The propagated signal may take any of a variety of forms, including electromagnetic, optical, and the like, or any suitable combination. The computer readable medium can be any computer readable medium that can communicate, propagate, or transport the program for use by or in connection with an instruction execution system, apparatus, or device. Program code on a computer readable medium may be propagated over any suitable medium, including radio, electrical cable, fiber optic cable, radio frequency signals, or the like, or any combination of the preceding.

Additionally, the order in which elements and sequences of the processes described herein are processed, the use of alphanumeric characters, or the use of other designations, is not intended to limit the order of the processes and methods described herein, unless explicitly claimed. While various presently contemplated embodiments of the invention have been discussed in the foregoing disclosure by way of example, it is to be understood that such detail is solely for that purpose and that the appended claims are not limited to the disclosed embodiments, but, on the contrary, are intended to cover all modifications and equivalent arrangements that are within the spirit and scope of the embodiments herein. For example, although the system components described above may be implemented by hardware devices, they may also be implemented by software-only solutions, such as installing the described system on an existing server or mobile device.

Similarly, it should be noted that in the preceding description of embodiments of the application, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one or more of the embodiments. This method of disclosure, however, is not intended to require more features than are expressly recited in the claims. Indeed, the embodiments may be characterized as having less than all of the features of a single embodiment disclosed above.

Numerals describing the number of components, attributes, etc. are used in some embodiments, it being understood that such numerals used in the description of the embodiments are modified in some instances by the use of the modifier "about", "approximately" or "substantially". Unless otherwise indicated, "about", "approximately" or "substantially" indicates that the number allows a variation of ± 20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximations that may vary depending upon the desired properties of the individual embodiments. In some embodiments, the numerical parameter should take into account the specified significant digits and employ a general digit preserving approach. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the range are approximations, in the specific examples, such numerical values are set forth as precisely as possible within the scope of the application.

Although the present invention has been described with reference to the present specific embodiments, it will be appreciated by those skilled in the art that the above embodiments are merely illustrative of the present invention, and various equivalent changes and substitutions may be made without departing from the spirit of the invention, and therefore, it is intended that all changes and modifications to the above embodiments within the spirit and scope of the present invention be covered by the appended claims.