CN116001269A - Photo-curing three-dimensional printing method and equipment - Google Patents

Abstract

The invention provides a photo-curing three-dimensional printing method, which comprises the following steps: obtaining a three-dimensional data model of the printing object; dividing the three-dimensional data model into a plurality of printing layers, wherein each printing layer corresponds to an original exposure image; dividing each original exposure image into a plurality of sub-images with equal size, wherein each sub-image corresponds to one imaging unit in an imaging system; dividing each sub-image into N sub-areas with the same size, wherein N is an integer greater than or equal to 2; and carrying out layer-by-layer exposure curing on the photosensitive material according to each original exposure image by adopting an imaging system, wherein in the exposure curing process of each printing layer, the imaging system is moved to enable each imaging unit to be aligned with each sub-area in the sub-image in sequence according to a preset path, and the preset path comprises at least one X-shaped route, wherein in the moving process of the imaging system, the positions of the sub-areas aligned by each imaging unit in the sub-image are the same.

Description

Photo-curing three-dimensional printing method and equipment

Technical Field

The invention mainly relates to the technical field of three-dimensional printing, in particular to a photo-curing three-dimensional printing method and equipment.

Background

The three-dimensional (3D) printing technology is characterized in that a computer three-dimensional design model is taken as a blue book, special materials such as metal powder, ceramic powder, plastics, cell tissues and the like are stacked and bonded layer by utilizing a laser beam, a hot-melt nozzle and the like through a software layered discrete and numerical control molding system, and finally, a solid product is manufactured by stacking and molding. Different from the traditional manufacturing industry that the raw materials are shaped and cut in a mechanical processing mode such as a die, a turning milling mode and the like to finally produce a finished product, the three-dimensional entity is changed into a plurality of two-dimensional planes through 3D printing, and the manufacturing complexity is greatly reduced through material processing and layer-by-layer stacking production. The digital manufacturing mode can directly generate parts with any shape from the computer graphic data without complex process, huge machine tool and numerous manpower, so that the production and manufacturing can be extended to a wider production crowd range.

At present, the forming mode of the 3D printing technology is continuously evolving, and the used materials are also various. Among the various molding methods, the photo-curing method is a more mature method. The photocuring method is to utilize the principle that the photosensitive resin is cured after being irradiated by ultraviolet laser to carry out 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 structural schematic diagram of a photo-curing type 3D printing apparatus. Referring to fig. 1, the 3D printing apparatus 100 includes a material tank 110 for accommodating a photosensitive resin, an imaging system 120 for curing the photosensitive resin, and a lift 130 for connecting a molded workpiece. The imaging system 120 is positioned above the chute 110 and is configured to illuminate the beam image to cure a layer of photosensitive resin on the surface of the chute 110. After each time the imaging system 120 irradiates the light beam image to cure one layer of photosensitive resin, the lifting table 130 drives the molded layer of photosensitive resin to slightly descend, and the cured top surface of the workpiece uniformly spreads the photosensitive resin through the scraping plate 131 to wait for the next irradiation. And by means of the circulation, the three-dimensional workpiece formed in a layer-by-layer accumulated mode can be obtained.

The surface quality of the molded workpiece is largely dependent on the resolution of the image as each layer cures. The imaging system 120 in the photo-curing type 3D printing apparatus generally adopts technologies such as liquid crystal display (Liquid Crystal Display, LCD), liquid crystal on silicon (Liquid Crystal on Silicon, LCOS), digital light processing (Digital Light Procession, DLP), etc., but the imaging element with high resolution cannot be widely used due to limitations of manufacturing process and manufacturing cost, etc.

Disclosure of Invention

The invention aims to provide a low-cost high-resolution photo-curing three-dimensional printing method and equipment.

In order to solve the technical problems, the invention provides a photo-curing three-dimensional printing method, which is characterized by comprising the following steps: obtaining a three-dimensional data model of the printing object; dividing the three-dimensional data model into a plurality of printing layers, wherein each printing layer corresponds to an original exposure image; dividing each original exposure image into a plurality of sub-images with equal size, wherein each sub-image corresponds to one imaging unit in an imaging system; dividing each sub-image into N sub-areas with the same size, wherein N is an integer greater than or equal to 2; and carrying out layer-by-layer exposure and solidification on the photosensitive material according to each original exposure image by adopting the imaging system, wherein in the exposure and solidification process of each printing layer, the imaging system is moved to enable each imaging unit to be aligned with each sub-area in the sub-image in sequence according to a preset path, the preset path comprises at least one X-shaped route, and in the movement process of the imaging system, the positions of the sub-areas aligned by each imaging unit in the sub-image are the same.

In one embodiment of the present invention, the step of dividing each sub-image into n×n equal-sized sub-areas comprises: each sub-image is divided into N rows by N columns of equal size sub-regions by rows and columns, the preset path further comprising a straight line path along one of the rows or columns.

In one embodiment of the present invention, the step of performing layer-by-layer exposure curing of the photosensitive material according to each of the original exposure images using the imaging system comprises: sequentially allocating a sequence number i to each sub-region in each sub-image according to the preset path, wherein the sequence numbers of the sub-regions in the same position in each sub-image are the same, and i is a positive integer less than or equal to N; sequentially extracting an ith sub-area image in each sub-area from each sub-image according to the sequence of the sequence numbers and combining to generate an ith combined exposure image; moving the imaging system to a preset position in the preset path according to the preset path; loading a combined exposure image corresponding to the preset position; and turning on an exposure light source in the imaging system to irradiate the photosensitive material according to the combined exposure image.

In an embodiment of the invention, the imaging unit determines to irradiate or not irradiate the photosensitive material corresponding to the subarea according to the combined exposure image.

In an embodiment of the present invention, further comprising: after the irradiation of one combined exposure image is completed, the exposure light source is turned off, and the imaging system is moved to the next preset position.

In an embodiment of the present invention, N is an even number greater than or equal to 4.

In an embodiment of the present invention, the plurality of sub-areas of N rows by N columns form a matrix, and the start point of the preset path is a sub-area located at the lower left corner of the matrix.

The present invention also provides a light-curing three-dimensional printing device for solving the above technical problems, which is characterized by comprising: the model acquisition module is used for acquiring a three-dimensional data model of the printing object; the layering module is used for dividing the three-dimensional data model into a plurality of printing layers, and each printing layer corresponds to an original exposure image; the image processing module is used for dividing each original exposure image into a plurality of sub-images with equal sizes, each sub-image corresponds to one imaging unit in the imaging system, and dividing each sub-image into N times N sub-areas with equal sizes, wherein N is an integer greater than or equal to 2; an imaging system comprising a plurality of imaging units for performing layer-by-layer exposure curing of the photosensitive material according to each of the original exposure images; and the controller is used for moving the imaging system in the exposure and solidification process of each printing layer, so that each imaging unit is aligned with each sub-region in the sub-image in sequence according to a preset path, wherein the preset path comprises at least one X-shaped route, and the positions of the sub-regions aligned by each imaging unit in the sub-image are the same in the moving process of the imaging system.

In an embodiment of the present invention, the image processing module is further configured to divide each sub-image into N rows by N columns of equal-sized sub-regions according to rows and columns, and the preset path further includes a straight line path along one of the rows or columns.

In an embodiment of the invention, the imaging system comprises an exposure light source, and the controller is further used for controlling the on and off of the exposure light source.

In an embodiment of the present invention, the image processing module is further configured to generate n×n combined exposure images according to the original exposure image, including: sequentially allocating a sequence number i to each sub-region in each sub-image according to the preset path, wherein the sequence numbers of the sub-regions in the same position in each sub-image are the same, and i is a positive integer less than or equal to N; and sequentially extracting an ith sub-area image in each sub-area from each sub-image according to the sequence of the sequence numbers and combining to generate an ith combined exposure image.

In an embodiment of the present invention, the controller is further configured to move the imaging system to a preset position in the preset path according to the preset path, load a combined exposure image corresponding to the preset position, and turn on an exposure light source in the imaging system, and irradiate the photosensitive material according to the combined exposure image.

In an embodiment of the invention, the imaging unit determines to irradiate or not irradiate the photosensitive material corresponding to the subarea according to the combined exposure image.

In an embodiment of the invention, after completing the irradiation of one combined exposure image, the controller is further configured to turn off the exposure light source and move the imaging system to a next preset position.

According to the three-dimensional printing method and the three-dimensional printing equipment, the plurality of sub-areas are exposed and solidified through the preset paths comprising the X-shaped paths, so that the exposure degrees suffered by the sub-areas are relatively even, voxels which are uniformly distributed can be obtained, the resolution and the precision of a printing finished product are improved, the printing finished product has a smooth surface, the surface quality is improved, and the deformation risk caused by stress is reduced.

Drawings

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

fig. 1 is a basic structural schematic diagram of a photo-curing type 3D printing apparatus;

FIG. 2A is a schematic diagram of the displacement of a single pixel point in a pixel multiplexing technique;

FIG. 2B is a schematic illustration of a contoured surface formed using the pixel multiplexing technique shown in FIG. 2A;

FIG. 3 is an exemplary flow chart of a method of photo-curing three-dimensional printing in accordance with one embodiment of the present invention;

FIG. 4 is a schematic view of the outline of a partial region of a print layer and the sequence of sub-regions for performing exposure curing in a three-dimensional printing method employing an embodiment of the present invention;

FIG. 5 is a schematic illustration of 16 combined exposure images extracted from the original exposure image shown in FIG. 4;

FIG. 6 is a schematic diagram of a printing effect of a three-dimensional printing method according to an embodiment of the present invention;

fig. 7 is a system block diagram of a photo-curing type three-dimensional printing apparatus according to an embodiment of the present invention.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are used in the description of the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some examples or embodiments of the present application, and it is obvious to those skilled in the art that the present application may be applied to other similar situations according to the drawings without inventive effort. Unless otherwise apparent from the context of the language or otherwise specified, like reference numerals in the figures refer to like structures or operations.

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

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

In the description of the present application, it should be understood that, where azimuth terms such as "front, rear, upper, lower, left, right", "transverse, vertical, horizontal", and "top, bottom", etc., indicate azimuth or positional relationships generally based on those shown in the drawings, only for convenience of description and simplification of the description, these azimuth terms do not indicate and imply that the apparatus or elements referred to must have a specific azimuth or be constructed and operated in a specific azimuth, and thus should not be construed as limiting the scope of protection of the present application; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "upper surface at … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition, the terms "first", "second", etc. are used to define the components, and are merely for convenience of distinguishing the corresponding components, and unless otherwise stated, the terms have no special meaning, and thus should not be construed as limiting the scope of the present application. Furthermore, although terms used in the present application are selected from publicly known and commonly used terms, some terms mentioned in the specification of the present application may be selected by the applicant at his or her discretion, the detailed meanings of which are described in relevant parts of the description herein. Furthermore, it is required that the present application be understood, not simply by the actual terms used but by the meaning of each term lying within.

Flowcharts are used in this application to describe the operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in order precisely. Rather, the various steps may be processed in reverse order or simultaneously. At the same time, other operations are added to or removed from these processes.

In order to overcome the problem of lower resolution in the existing photo-curing 3D printing, a pixel multiplexing technology can be adopted to achieve a high-resolution printing effect at a lower cost, but certain problems still exist in the application of the photo-curing 3D printing method.

The pixel multiplexing technique refers to that any single exposure element is subjected to multiple effective and short-time exposure at different positions in an exposure area which is responsible for the exposure element in a physical displacement mode or an optical deflection mode, and smaller forming voxels are realized by controlling the exposure amount, so that the method is approximately equivalent to using a higher-resolution exposure element for photo-curing. The exposure element here may be an imaging element corresponding to one pixel. Fig. 2A is a schematic displacement diagram of a single exposure element in a pixel multiplexing technique. Referring to fig. 2A, the exposure area for which a single exposure element is responsible is divided into a matrix of 4*4, with each circle labeled with a numeral in the middle representing a subpixel. In fig. 2A, a single exposure element follows a zigzag path indicated by arrows from the O-point to the respective positions indicated by R1, R2, …, R7 in order to effect exposure of all 16 sub-pixels, one cured sub-voxel being formed at the position of each sub-pixel, the 16 sub-voxels forming a voxel corresponding to the exposure element. However, according to this line-by-line exposure, the current exposure will produce a cure reinforcement for one or several sub-voxels cured by the previous exposure, and the cured-reinforced voxels will consume the uncured resin of other sub-areas, so that the area exposed later cannot form the cured resin in a predetermined shape.

Fig. 2B is a schematic illustration of a contoured surface formed using the pixel multiplexing technique shown in fig. 2A. Referring to fig. 2B, the exposure area 210 is the exposure area for which the single exposure element shown in fig. 2A is responsible. Fig. 2B shows a total of 4 adjacent exposure areas, each of which is responsible for 4 individual exposure elements in the imaging system. Taking the exposure area 210 as an example, after the zigzag scanning, the area of the sub-voxel No. 1 located at the starting point is the largest and the areas of the sub-voxels No. 2, no. 3 and No. 4 are sequentially reduced due to the subsequent curing reinforcement for several times. The surface of the formed workpiece is formed with volume features that are small after large in the row direction, and larger sub-voxels typically significantly exceed their intended volume size, even engulfing adjacent sub-voxels. On the other hand, such progressive printing can accumulate stresses during exposure, which is detrimental to the later maintenance of the cured model, and even large deformations during printing. The pixel multiplexing technique according to fig. 2A and 2B reduces the actual resolution and accuracy of the printed product and also reduces the smoothness of the upper surface of the printed product.

Fig. 3 is an exemplary flowchart of a photo-curing type three-dimensional printing method according to an embodiment of the present invention. Referring to fig. 3, the printing method of this embodiment includes the steps of:

Step S310: obtaining a three-dimensional data model of the printing object;

step S320: dividing the three-dimensional data model into a plurality of printing layers, wherein each printing layer corresponds to an original exposure image;

step S330: dividing each original exposure image into a plurality of sub-images with equal size, wherein each sub-image corresponds to one imaging unit in an imaging system;

step S340: dividing each sub-image into N sub-areas with the same size, wherein N is an integer greater than or equal to 2; and

step S350: and (3) carrying out layer-by-layer exposure and solidification on the photosensitive material according to each original exposure image by adopting an imaging system, and moving the imaging system in the exposure and solidification process of each printing layer to enable each imaging unit to be aligned with each sub-area in the sub-image in sequence according to a preset path, wherein the preset path comprises at least one X-shaped route, and the positions of the sub-areas aligned by each imaging unit in the sub-image are the same in the movement process of the imaging system.

The specific implementation method of steps S310 and S320 is not limited in the present invention, and may be implemented by using a three-dimensional printing method in the art. Steps S330 to S350 are printing steps to be performed for each print layer, and steps S330 to S350 may be cyclically performed until the exposure curing of each print layer of the entire three-dimensional data model is completed, thereby obtaining a final molded workpiece.

The above steps S330 to S350 are described below with reference to fig. 4 to 6.

Fig. 4 is a schematic diagram showing the outline of a partial region of a printing layer and the sequence of sub-regions to be exposed and cured in a photo-curing three-dimensional printing method according to an embodiment of the present invention. Referring to fig. 4 and 2B, fig. 4 is similar to fig. 2B in that fig. 4 also shows 4 adjacent exposure areas, each of which is responsible for 4 individual imaging units in the imaging system.

The illustration in fig. 4 is for illustration only and is not intended to limit the size, arrangement, number, etc. of the exposed areas.

The invention does not limit the size and pattern of the original exposure image. Fig. 4 shows an example in which an original exposure image is divided into two areas along a diagonal line, wherein most of the area located at the upper right is filled with white indicating that exposure is required and most of the area located at the lower left is filled with diagonal lines indicating that exposure is not required. To form the original exposure image with and without exposure.

In step S330, the original exposure image is divided into a plurality of sub-images of equal size. Referring to fig. 4, the original exposure image is divided into 4 sub-images C1, C2, C3, C4 of equal size. Wherein each sub-image is square and is distributed adjacent to each other. The invention does not limit the shape, size, number and arrangement of the sub-images. For example, the sub-images may be staggered rather than aligned in rows and columns as shown in fig. 4.

In step S330, each sub-image corresponds to one imaging unit in the imaging system. The imaging system provides a light source during the three-dimensional printing process and irradiates the liquid photosensitive material corresponding to each printing layer according to the original exposure image corresponding to the printing layer. An imaging system may include a plurality of imaging units, the number of which is related to the resolution of the three-dimensional model to be printed. For example, with an LCD imaging device having a resolution of 1920×1080, the number of imaging units included therein is 1920×1080. Accordingly, each sub-image also corresponds to an image of one pixel. The size of the sub-image corresponds to the size of one pixel.

In step S340, each sub-image is divided into N equal-sized sub-areas, where N is an integer equal to or greater than 2. In the embodiment shown in fig. 4, n=4. Each sub-image is divided into 4*4 equally sized sub-regions, each indicated by a number from 1 to 16 in fig. 4. In fig. 4, each sub-region is square. The invention is not limited to the shape, size, number and arrangement of the sub-areas. For example, the sub-regions may be rectangular, triangular, etc. of equal size, and the distribution may be staggered rather than aligned in rows and columns as shown in fig. 4.

In some embodiments, N is an even number greater than or equal to 4. For example, n=4, 6, 8, 10, etc.

In step S350, the three-dimensional printing apparatus includes an imaging system, and when each print layer is exposed and cured, the imaging system irradiates the photosensitive material according to the original exposure image corresponding to the print layer of the layer, and exposes the photosensitive material in the sub-region to be exposed. The imaging system comprises a plurality of imaging units, each imaging unit corresponding to a sub-image, i.e. being responsible for the exposure of a sub-image. As shown in fig. 4, it is assumed that the imaging unit G1 is responsible for the sub-image C1, the imaging unit G2 is responsible for the sub-image C2, and so on. The positional relationship of the imaging units G1-G4 is similar to that of the sub-images C1-C4 in the imaging system.

Assuming that at start-up the imaging units are aligned to one of the sub-areas, e.g. sub-area 1, each imaging unit is aligned to sub-area 1 of its corresponding sub-image. When the imaging system is moved, a plurality of imaging units are simultaneously moved, and the movement path of each imaging unit is a preset path.

The preset paths are marked in figure 4 with a number from small to large, that is to say in order from 1 to 16, it being clear that such preset paths comprise at least one X-shaped route, for example 4X-shaped routes in the embodiment shown in figure 4, 1-2-3-4, 5-6-7-8, 9-10-11-12, 13-14-15-16 respectively. The preset path of the present invention is a non-progressive scan route. For the embodiment with N being greater than or equal to 2, compared with the previous progressive scanning, two adjacent position points in the preset path are not in the same row, and for some adjacent position points, the two adjacent position points are not in the same row or the same column.

The invention does not limit whether the preset path is a straight line or a curve. That is to say that the movement from sub-area 1 to sub-area 2 can be either rectilinear or curvilinear, in any case comprising at least one X-shaped path with crossing points in the preset path. For matrices exceeding 3*3, the preset path is on two oblique lines forming an X-shaped route, so that at least one sub-area is spaced between two end points of the oblique lines as far as possible, for example, a sub-area 5 is spaced between the sub-areas 1 and 2 in fig. 4, and a sub-area 5 is also spaced between the sub-areas 3 and 4, thus forming the X-shaped route 1-2-3-4. Since the X-shaped routes 1-2-3-4 have been formed, there is no spacing of the sub-areas from sub-area 4 to sub-area 5, but instead another X-shaped route 5-6-7-8 is started to be formed in order to move the imaging system to sub-area 5.

In some embodiments, the step of dividing each sub-image into n×n equal-sized sub-areas in step S340 includes: each sub-image is divided into N rows by N columns of equal-sized sub-regions by rows and columns, and the preset path further includes a straight line path along one of the rows or columns. These embodiments define the arrangement of the sub-regions in a matrix of N rows by N columns, as shown in fig. 4, that is, the sub-regions are aligned in rows and columns. According to the embodiments, in order to increase the printing speed, according to the principle of the shortest path, the preset path of the imaging system moves along a straight line, wherein the X-shaped path includes two straight lines intersecting each other, for example, a slant line from the sub-area 1 to the sub-area 2 and a slant line from the sub-area 3 to the sub-area 4, and the moving path is a connection line of the two sub-areas; from the sub-area 2 to the sub-area 3, the moving route is a straight line in the column direction. In fig. 4, the columns are vertical and the behavior is horizontal. It will be appreciated that if the predetermined path is continuous, a straight line path along a row or column is also necessarily required in order to form an X-shaped path.

In the embodiment shown in fig. 4, the preset path includes only an X-shaped route and a straight route in the column direction, and does not include a straight route in the row direction. In other embodiments, the preset path may include only an X-shaped path and a straight path along the row direction, and not a straight path along the column direction.

In the embodiment of the invention, some position points pass through only once and some position points pass through multiple times during the process that the imaging system moves along the preset path. The imaging system exposes only once at each location point, no matter how many times.

In some embodiments, the step of performing layer-by-layer exposure curing of the photosensitive material using the imaging system according to each of the original exposure images in step S350 includes:

step S351: and sequentially allocating a sequence number i to each sub-region in each sub-image according to a preset path, wherein the sequence numbers of the sub-regions in the same position in each sub-image are the same, and i is a positive integer less than or equal to N.

Referring to fig. 4, the number marked in each sub-region is the sequence number of the sub-region, and in the embodiment shown in fig. 4, n=4, the sequence number is a positive integer from 1 to 16. As shown in fig. 4, in each of the sub-images C1 to C4, the sequence numbers of the sub-areas at the same position are the same.

Step S352: and sequentially extracting an ith sub-area image in each sub-area from each sub-image according to the sequence of the sequence numbers and combining to generate an ith combined exposure image.

Fig. 5 is a schematic diagram of 16 combined exposure images extracted from the original exposure image shown in fig. 4. Taking the 1 st combined exposure image D1 as an example, the combined exposure image includes 4 sub-area images extracted from 4 sub-images C1 to C4, and the serial numbers are all 1, and thus four squares numbered 1 are shown in the figure to be combined together to form the combined exposure image D1. Referring to fig. 4, in the sub-images C1 to C3, the images in the sub-region 1 are all filled with oblique lines indicating that exposure is not required, and in the sub-image C4, the images in the sub-region 1 are filled with white indicating that exposure is required. The imaging units G1-G3 need not provide illumination when the four imaging units G1-G4 in the imaging system are aligned with the four sub-areas 1, respectively, and the imaging unit G4 needs to provide illumination. And so on, 16 combined exposure images shown in fig. 5, each of which is composed of four sub-area images, are generated in order from 1 to 16, respectively.

Step S353: and moving the imaging system to a preset position in the preset path according to the preset path.

The imaging unit may not be aligned to any sub-area before the entire exposure curing process is started. Then after the exposure curing process is started, the imaging system needs to be moved to the first position in the preset path, that is, the position of the sub-region with the sequence number 1, according to the preset path. The preset position corresponds to the position of each sub-area.

As shown in fig. 4, in some embodiments, a plurality of sub-areas of N rows by N columns form a matrix, and the start point of the preset path is the sub-area located at the lower left corner of the matrix. In other embodiments, the position of the start point of the preset path is not limited, and the position of any one of the sub-areas may be used as the start point of the preset path.

Step S354: loading a combined exposure image corresponding to the preset position.

For imaging systems, it is necessary at this step to load the combined exposure image currently to be employed into the corresponding components of the imaging system. As shown in fig. 5, the sequence numbers of the sub-areas at different preset positions are different, and the corresponding combined exposure images are also different. Thus, the correct combined exposure image needs to be loaded.

Step S355: an exposure light source in the imaging system is turned on, and the photosensitive material is irradiated according to the combined exposure image.

As shown in fig. 5, according to the previous steps S351-S354, each imaging unit has aligned the corresponding sub-area according to the serial number, and the imaging system has loaded the combined exposure image corresponding to the serial number, the exposure light source is turned on at this step, and exposure imaging is started.

In some embodiments, the imaging unit determines the photosensitive material corresponding to the illuminated or non-illuminated sub-region from the combined exposure image. It will be appreciated that the photosensitive material herein is a liquid photosensitive material, such as a liquid photosensitive resin, but may also be other mixed materials containing a liquid photosensitive resin, such as a slurry mixed with ceramic powder or metal powder.

For an imaging unit in an imaging system, the need for exposure also indicates that the imaging unit is on, so that light emitted by the light source irradiates a corresponding region on the photosensitive material through the imaging unit; the absence of exposure also indicates that the imaging unit is off, and light from the light source does not pass through the imaging unit to illuminate the corresponding area on the photosensitive material. In this step, according to the combined exposure image, some imaging units are in an on state and some imaging units are in an off state. As shown in fig. 5, taking the 16 th combined exposure image D16 as an example, the combined exposure image includes 4 sub-area images extracted from the 4 sub-images C1-C4, and the serial numbers are all 16, wherein, in the sub-images C1-C2, the images in the sub-areas 16 are all filled with oblique lines, which indicates that the imaging units G1 and G2 are in the off state at step S355; in sub-images C3-C4, the image in sub-area 16 fills in white, indicating that imaging units G3 and G4 are in an on state at step S355.

When one printing layer is printed, the position of each sub-area is traversed according to a preset path, and printing of an original exposure image corresponding to the one printing layer can be completed.

In some embodiments, after illumination of one combined exposure image is completed, the exposure light source is turned off, and the imaging system is moved to the next preset position. According to these embodiments, during printing of one print layer, it is necessary to switch the exposure light source on and off a number of times, which is related to the number of sub-areas. In the embodiment shown in fig. 5, the exposure light source needs to be turned on and off 16 times, respectively.

In some embodiments, in step S355, the exposure light source is turned on to illuminate the sub-region for a preset length of time. Assuming that the time length for a single imaging unit to irradiate one sub-image is T in a typical three-dimensional printing process, the preset length for the imaging unit to irradiate the sub-region is T/(n×n). In the embodiment shown in fig. 4, assuming t=1 second, the preset length is 1/16 second. According to this embodiment, the total exposure time is constant for one sub-image.

In some embodiments, the size of each sub-region is equal to 1/(n×n) pixels by 1 pixel. In some embodiments, one imaging unit corresponds to 1 pixel in the original exposure image. According to these embodiments, N x N exposures are performed in a sub-image using one imaging unit, which corresponds to an increase in resolution of the resulting image by at least a factor of N x N.

Fig. 6 is a schematic view of a printing effect of a three-dimensional printing method according to an embodiment of the present invention. The sub-images and sub-regions shown in fig. 6 correspond to the sub-images and sub-regions shown in fig. 4. Referring to fig. 6, taking the sub-image C1 as an example, since the preset path including the X-shaped route of the present invention is adopted, the size of the sub-region 1 which is intensified to be enlarged in the original progressive scan is significantly reduced, and the area sizes of the respective sub-regions are relatively averaged. As in fig. 6, the voxel area formed at sub-regions 1-4 is substantially equal in size. And, after the subareas 1-4 are solidified, the subareas 5 are positioned in a basin, and the external liquid photosensitive material is difficult to enter the subareas 5, so that the subareas 5 are limited to be further enlarged.

According to the three-dimensional printing method, the preset paths including the X-shaped paths are adopted to expose and solidify the plurality of subareas, so that the exposure degrees suffered by the subareas are relatively even, voxels which are uniformly distributed can be obtained, the resolution and the precision of a printing finished product are improved, the printing finished product has a smooth surface, the surface quality is improved, and the deformation risk caused by stress is reduced.

Fig. 7 is a system block diagram of a photo-curing type three-dimensional printing apparatus according to an embodiment of the present invention. The photo-curable three-dimensional printing method of the present invention described above may be embodied by the photo-curable three-dimensional printing apparatus 700, and thus, the foregoing description will be used to describe the photo-curable three-dimensional printing apparatus 700 of the present invention, and the same will not be repeated.

Referring to fig. 7, the light-curable three-dimensional printing apparatus 700 of this embodiment includes a model acquisition module 710, a layering module 720, an image processing module 730, an imaging system 740, and a controller 750. Wherein, the model acquisition module 710 is configured to acquire a three-dimensional data model of the printing object; the layering module 720 is configured to divide the three-dimensional data model into a plurality of printing layers, each printing layer corresponding to an original exposure image; the image processing module 730 is configured to divide each original exposure image into a plurality of sub-images with equal sizes, each sub-image corresponds to one imaging unit in the imaging system 740, and divide each sub-image into n×n sub-areas with equal sizes, where N is an integer greater than or equal to 2; the imaging system 740 includes a plurality of imaging units for performing layer-by-layer exposure curing of the photosensitive material according to each of the original exposure images; the controller 750 is configured to move the imaging system 740 during exposure and curing of each print layer, so that each imaging unit is sequentially aligned to each sub-area in the sub-image according to a preset path, where the preset path includes at least one X-shaped path, and during movement of the imaging system 740, the positions of the sub-areas aligned by each imaging unit in the sub-image are the same.

In some embodiments, the image processing module 730 is further configured to divide each sub-image into N rows by N columns of equal-sized sub-regions according to rows and columns, and the preset path further includes a straight line path along one of the rows or columns.

In some embodiments, imaging system 740 includes an exposure light source, and controller 750 is also used to control the turning on and off of the exposure light source.

In some embodiments, the image processing module 730 is further configured to generate n×n combined exposure images from the original exposure images, including: sequentially allocating a sequence number i to each sub-region in each sub-image according to a preset path, wherein the sequence numbers of the sub-regions in the same position in each sub-image are the same, and i is a positive integer less than or equal to N; and sequentially extracting an ith sub-area image in each sub-area from each sub-image according to the sequence of the sequence numbers and combining to generate an ith combined exposure image.

In some embodiments, the controller 750 is further configured to move the imaging system 740 to a preset position in the preset path according to the preset path, load a combined exposure image corresponding to the preset position, and turn on an exposure light source in the imaging system 740 to irradiate the photosensitive material according to the combined exposure image.

In some embodiments, the imaging unit determines the photosensitive material corresponding to the illuminated or non-illuminated sub-region from the combined exposure image.

In some embodiments, after the illumination of one combined exposure image is completed, the controller 750 is also configured to turn off the exposure light source, moving the imaging system 740 to the next preset position.

In some embodiments, controller 750 employs micro-actuators to move imaging system 740.

After printing of one printing layer is completed, printing is carried out on the next printing layer by adopting the same method, and finally printing of the whole three-dimensional data model is completed.

The photocuring type three-dimensional printing equipment can obtain a molded workpiece with higher resolution and precision at low cost, and the molded workpiece has the advantages of stable structure, difficult deformation and smooth surface.

While the basic concepts have been described above, it will be apparent to those skilled in the art that the above disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements, and adaptations of the present application may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within this application, and are therefore within the spirit and scope of the exemplary embodiments of this application.

Meanwhile, the present application uses specific words to describe embodiments of the present application. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic is associated with at least one embodiment of the present application. Thus, it should be emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various positions in this specification are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the present application may be combined as suitable.

Some aspects 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 a "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 take the form of a computer product, comprising 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, tape … …), optical disk (e.g., compact disk CD, digital versatile disk DVD … …), smart card, 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 on a variety of forms, including electro-magnetic, optical, etc., or any suitable combination thereof. A computer readable medium can be any computer readable medium that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code located on a computer readable medium may be propagated through any suitable medium, including radio, cable, fiber optic cable, radio frequency signals, or the like, or a combination of any of the foregoing.

Likewise, it should be noted that in order to simplify the presentation disclosed herein and thereby aid in understanding one or more inventive embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof. This method of disclosure, however, is not intended to imply that more features than are presented in the claims are required for the subject application. Indeed, less than all of the features of a single embodiment disclosed above.

In some embodiments, numbers describing the components, number of attributes are used, it being understood that such numbers being used in the description of embodiments are modified in some examples by the modifier "about," approximately, "or" substantially. Unless otherwise indicated, "about," "approximately," or "substantially" indicate that the number allows for a 20% variation. Accordingly, in some embodiments, numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by the individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and employ a method for preserving the general number of digits. Although the numerical ranges and parameters set forth herein are approximations that may be employed in some embodiments to confirm the breadth of the range, in particular embodiments, the setting of such numerical values is as precise as possible.

While the present application has been described with reference to the present specific embodiments, those of ordinary skill in the art will recognize that the above embodiments are for illustrative purposes only, and that various equivalent changes or substitutions can be made without departing from the spirit of the present application, and therefore, all changes and modifications to the embodiments described above are intended to be within the scope of the claims of the present application.

Claims (14)

1. A photo-curable three-dimensional printing method, comprising:

obtaining a three-dimensional data model of the printing object;

dividing the three-dimensional data model into a plurality of printing layers, wherein each printing layer corresponds to an original exposure image;

dividing each original exposure image into a plurality of sub-images with equal size, wherein each sub-image corresponds to one imaging unit in an imaging system;

dividing each sub-image into N sub-areas with the same size, wherein N is an integer greater than or equal to 2; and

and carrying out layer-by-layer exposure and solidification on the photosensitive material by adopting the imaging system according to each original exposure image, and moving the imaging system in the exposure and solidification process of each printing layer to enable each imaging unit to be aligned with each sub-area in the sub-image in sequence according to a preset path, wherein the preset path comprises at least one X-shaped route, and the positions of the sub-areas aligned by each imaging unit in the sub-image are the same in the movement process of the imaging system.

2. The method of three-dimensional printing according to claim 1, wherein the step of dividing each sub-image into N x N equal-sized sub-areas comprises: each sub-image is divided into N rows by N columns of equal size sub-regions by rows and columns, the preset path further comprising a straight line path along one of the rows or columns.

3. The method of claim 1, wherein the step of exposing and curing the photosensitive material layer by layer using the imaging system according to each of the original exposure images comprises:

sequentially allocating a sequence number i to each sub-region in each sub-image according to the preset path, wherein the sequence numbers of the sub-regions in the same position in each sub-image are the same, and i is a positive integer less than or equal to N;

sequentially extracting an ith sub-area image in each sub-area from each sub-image according to the sequence of the sequence numbers and combining to generate an ith combined exposure image;

moving the imaging system to a preset position in the preset path according to the preset path;

loading a combined exposure image corresponding to the preset position; and

an exposure light source in the imaging system is turned on, and the photosensitive material is irradiated according to the combined exposure image.

4. A photo-curable three-dimensional printing method according to claim 3, wherein the imaging unit determines whether or not the photosensitive material corresponding to the sub-region is irradiated according to the combined exposure image.

5. The light-curable three-dimensional printing method according to claim 1, further comprising: after the irradiation of one combined exposure image is completed, the exposure light source is turned off, and the imaging system is moved to the next preset position.

6. The photocurable three-dimensional printing method according to claim 1, wherein N is an even number of 4 or more.

7. The method of claim 1, wherein the plurality of sub-areas of N rows by N columns form a matrix, and the start point of the predetermined path is a sub-area located at a lower left corner of the matrix.

8. A photo-curable three-dimensional printing apparatus, comprising:

the model acquisition module is used for acquiring a three-dimensional data model of the printing object;

the layering module is used for dividing the three-dimensional data model into a plurality of printing layers, and each printing layer corresponds to an original exposure image;

the image processing module is used for dividing each original exposure image into a plurality of sub-images with equal sizes, each sub-image corresponds to one imaging unit in the imaging system, and dividing each sub-image into N times N sub-areas with equal sizes, wherein N is an integer greater than or equal to 2;

an imaging system comprising a plurality of imaging units for performing layer-by-layer exposure curing of the photosensitive material according to each of the original exposure images;

and the controller is used for moving the imaging system in the exposure and solidification process of each printing layer, so that each imaging unit is aligned with each sub-region in the sub-image in sequence according to a preset path, wherein the preset path comprises at least one X-shaped route, and the positions of the sub-regions aligned by each imaging unit in the sub-image are the same in the moving process of the imaging system.

9. The light-curable three-dimensional printing device of claim 8, wherein the image processing module is further configured to divide each sub-image into N rows by N columns of equal-sized sub-areas by rows and columns, the preset path further comprising a straight line path along one of the rows or columns.

10. The light-curable three-dimensional printing device according to claim 8, wherein the imaging system includes an exposure light source, and the controller is further configured to control on and off of the exposure light source.

11. The light-curable three-dimensional printing device of claim 10, wherein the image processing module is further configured to generate N x N combined exposure images from the original exposure image, comprising:

sequentially allocating a sequence number i to each sub-region in each sub-image according to the preset path, wherein the sequence numbers of the sub-regions in the same position in each sub-image are the same, and i is a positive integer less than or equal to N; and

and sequentially extracting an ith sub-area image in each sub-area from each sub-image according to the sequence of the sequence numbers and combining to generate an ith combined exposure image.

12. The light-curable three-dimensional printing apparatus according to claim 10, wherein the controller is further configured to move the imaging system to one preset position in the preset path according to the preset path, load a combined exposure image corresponding to the preset position, and turn on an exposure light source in the imaging system to irradiate the photosensitive material according to the combined exposure image.

13. The light-curable three-dimensional printing apparatus according to claim 12, wherein the imaging unit determines whether to irradiate or not irradiate the photosensitive material corresponding to the sub-region based on the combined exposure image.

14. The light-curable three-dimensional printing apparatus according to claim 12, wherein after the irradiation of one combined exposure image is completed, the controller is further configured to turn off the exposure light source, and move the imaging system to a next preset position.

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