CN116551979A

CN116551979A - Photo-curing 3D printing device and printing method

Info

Publication number: CN116551979A
Application number: CN202310473599.XA
Authority: CN
Inventors: 白家鸣; 袁金斯; 蔡鹏�; 胡博文; 王海江
Original assignee: Southwest University of Science and Technology
Current assignee: Southwest University of Science and Technology
Priority date: 2023-04-25
Filing date: 2023-04-25
Publication date: 2023-08-08

Abstract

The invention provides a photocuring 3D printing device and a printing method; the photocuring 3D printing device comprises a printing bearing mechanism, a scraper feeding mechanism and a UV (ultraviolet) ray machine; the photocuring 3D printing method comprises the steps of pre-processing a model, spreading according to requirements, and exposing according to requirements; the model preprocessing comprises the steps of generating a frame model, a slice file and printing parameter setting for protecting slurry; spreading according to needs is achieved through slicing files and coordinated control of movement of a feeding nozzle in a first horizontal direction and a second horizontal direction and material extrusion; the printing platform descends layer by layer, and the scraper scrapes the liquid level to control the layer thickness; and controlling the UV ray machine to expose on demand through setting parameters in the slice file. The printing liquid level can be scraped while feeding, the leveling waiting time is not needed, and the printing speed is high; the slurry is directly paved on a printing platform, and is combined with the paving as required and a small amount of slurry to be printed; the extrusion spreading combined with the scraping knife is scraped, and the application range of the viscosity of the sizing agent is wide; flexible feeding and light curing printing of multiple materials.

Description

Photo-curing 3D printing device and printing method

Technical Field

The invention relates to the field of additive manufacturing, in particular to a photocuring 3D printing device and a printing method.

Background

Photo-curing 3D printing technology is one of the most mature and widely used additive manufacturing technologies at present. Compared with other 3D printing technologies, the method has the advantages of high precision, good surface quality, capability of being directly applied as a functional part to a molded part, capability of molding complex and fine parts and the like. Similar to other 3D printing technologies, the photo-curing 3D printing also uses the principle of layer-by-layer accumulation molding of materials, a three-dimensional model is divided into a plurality of plane sheets by software slicing, and then ultraviolet light beams with certain wavelength are used for selectively curing and molding the photosensitive resin; and finally obtaining the target part through layer-by-layer solidification and accumulation.

The sinking type photo-curing printer has the advantages of wide material adaptability, good model structure performance and difficult deformation due to no need of considering the release problem and the influence of gravity action of a printing piece, and is widely applied. The common sinking type photo-curing printing principle is that after the upper layer is cured, the printing platform is immersed into photo-curing printing slurry for material supplementing, lifted to a certain height, and then the upper and lower fine adjustment of the printing platform is controlled through liquid level calibration, and ultraviolet exposure is carried out after the liquid level is leveled (usually, the printing slurry needs to be fully leveled). The control of the layer thickness during printing is mainly dependent on leveling of the liquid surface and dynamic calibration of the liquid level of the printer.

Since printing paste generally has a certain viscosity and surface tension, when printing is performed by using printing paste with high viscosity, a long leveling waiting time is required (for example, when the leveling waiting time is not long enough, a certain degree of edge deformation phenomenon occurs on the edge of a printing piece, which leads to morphology distortion), and if the leveling capability of the liquid level is not good, the waiting time is very long and even leads to printing failure.

Meanwhile, the submerged photo-curing printing generally requires adding a large amount of photosensitive paste in advance in a cylinder to perform printing, and particularly, a large amount of paste is required when printing higher parts. For printing of valuable slurries, the cost is high; for slurries unsuitable for long-term storage, the material costs are extremely high. Therefore, it is not suitable for printing of new materials, especially valuable functional materials.

In addition, conventional submerged photo-curing printers are not capable of printing multiple materials, limiting the application and development of this technology. Multi-material 3D printing makes it easier and efficient to manufacture products with multiple properties by printing on the same component using two or more different materials at the same time, which is of great importance in the manufacture of complex functional products and components. In multi-material 3D printing, different materials may be used to control various properties of the product, such as mechanical properties, wear resistance, electrical conductivity, etc. The technology provides a wide development space for manufacturing highly customized and precise products, and provides new possibility for product development and manufacturing in the fields of medical treatment, aerospace, automobiles, electronics and the like. Therefore, further development and application of the multi-material photo-curing printing technology are necessary.

The above problems are technical problems to be solved in the art.

Disclosure of Invention

The invention provides a photocuring 3D printing device and a printing method, which can smooth the printing liquid level, avoid leveling waiting time and realize high printing speed while feeding; the slurry is directly paved on a printing platform, and printing can be performed by combining the slurry with the required paving and a small amount of slurry; the extrusion spreading combined with the scraping knife is scraped, and the application range of the viscosity of the sizing agent is wide; flexible feeding and capability of performing multi-material photo-curing printing.

According to a first aspect, the present application provides a photo-curing 3D printing method, printing with a photo-curing 3D printing device, the photo-curing 3D printing device comprising:

the printing platform is used for bearing printing pieces and printing slurry;

scraper feeding mechanism, its set up in print platform's top, scraper feeding mechanism includes: one or more feed assemblies and a doctor blade, the doctor blade being movable in a first horizontal direction, the feed assemblies having a feed nozzle located on one side of the doctor blade in the first horizontal direction and movable with the doctor blade in the first horizontal direction, and the feed nozzle being independently movable in a second horizontal direction to extrude printing paste, the first horizontal direction being perpendicular to the second horizontal direction;

The UV light machine is arranged above the printing platform and is configured to project UV light corresponding to the slice pattern of the three-dimensional model to the direction of the printing platform so as to expose and solidify the printing slurry at the uppermost layer of the printing platform according to the requirement;

the photo-curing printing method comprises the following steps:

model pretreatment: generating a frame model which is enclosed outside the printing model in the horizontal direction and has the same height as the highest point of the printing model in the vertical direction according to the size of the printing model; combining the frame model and the printing model into one three-dimensional model, slicing the three-dimensional model to obtain a plurality of slice files, setting printing parameters for each slice file, and confirming the position of a layer to be printed on the printing platform based on the slice files;

printing preparation: adjusting the position of the printing platform to enable the surface of the printing platform to be positioned at the focus of the UV ray machine; adjusting the height of the scraper to enable the bottom of the scraper to be leveled with the top of the printing platform;

single-layer printing: lowering the printing platform by the height of one layer to be printed, moving the feeding nozzle along the second horizontal direction and extruding printing slurry based on the printing parameters corresponding to the slice file, and simultaneously moving the scraper towards the side provided with the feeding nozzle in the first horizontal direction so as to move the scraper from an initial position to a final position in the first horizontal direction; spreading materials in the layer to be printed according to requirements by cooperatively controlling the movement of the feeding nozzle in the first horizontal direction and the second horizontal direction, and controlling the layer thickness of the layer to be printed and scraping off the residual materials by the scraper moving along the first horizontal direction; curing printing slurry, exposing the slurry scraped by the scraper according to the requirement by the UV light machine to cure the slurry, and resetting the scraper feeding mechanism;

And repeating the single-layer printing step until printing is completed.

In an alternative embodiment, in the slice file, the slice pattern of the frame model surrounds the periphery of the slice pattern of the print model; and/or the slice pattern of the frame model is square or circular.

In an alternative embodiment, the thickness of the rim model is determined based on the viscosity of the printing paste and the strength of the printed green body, and the thickness of the rim model is 0.5 to 5mm.

In an alternative embodiment, the printing parameters include one or more of a printing pattern, a layer thickness, an exposure intensity, and an exposure time corresponding to each of the layers to be printed.

In an alternative embodiment, the step of controlling the movement of the feed nozzle in the first horizontal direction and the second horizontal direction by coordination to spread the desired swath within the layer to be printed comprises:

determining a range to be fed based on the position of the layer to be printed on the printing platform; and determining a movement path of the feeding nozzle in a first horizontal direction and a second horizontal direction based on the slice pattern of the layer to be printed, wherein the feeding nozzle moves along the movement path and extrudes printing paste.

In an alternative embodiment, the step of on-demand exposure includes: and exposing the printing paste scraped by the scraper according to the exposure intensity and the exposure time set by the printing parameters through a UV (ultraviolet) ray machine and curing the printing paste according to a slice pattern to obtain a cured layer, wherein the cured layer comprises a cured pattern corresponding to the slice patterns of the printing model and the frame model.

In an alternative embodiment, when printing with at least two printing pastes, the number of feed assemblies corresponds one to the type of printing paste, wherein:

in the step of model preprocessing, the method further comprises the steps of: adding material properties to the three-dimensional model;

the printing parameters further include: the printing paste types of all areas in the slice file and the exposure parameters of all areas are determined based on the material properties;

the step of on-demand exposure further comprises the steps of: and respectively irradiating various printing pastes on the layer to be printed, and adjusting the exposure parameters of the UV ray machine based on the printing parameters corresponding to the irradiation areas.

According to a second aspect, the present application provides a photo-curing 3D printing device comprising:

The printing bearing mechanism comprises a printing platform and a lifting assembly, wherein the lifting assembly is connected with the printing platform so as to drive the printing platform to move in the vertical direction, and the printing platform is used for bearing printing pieces and printing slurry;

scraper feeding mechanism, its set up in print platform's top, scraper feeding mechanism includes: one or more feeding components, a scraper module, a connecting component, a first moving module and a second moving module,

the feed assembly having a feed nozzle for containing a printing paste, the feed nozzle for extruding the printing paste,

the scraper module is connected with the first movable module through a connecting component, a second movable module is arranged on the connecting component, the second movable module is positioned at one side of the scraper module in the first horizontal direction, the feeding nozzle is connected with the second movable module,

the first moving module can drive the connecting assembly to move along the first horizontal direction so as to drive the scraper module and the feeding nozzle to move along the first horizontal direction at the same time, and the second moving module can drive the feeding nozzle to move along the second horizontal direction which is perpendicular to the first horizontal direction;

The UV light machine is arranged above the printing bearing mechanism and is configured to project UV light corresponding to the slice pattern of the three-dimensional model to the direction of the printing platform so as to expose and solidify the printing slurry at the uppermost layer of the printing platform according to the requirement.

In an alternative embodiment, the doctor blade module includes a doctor blade, a doctor blade adjustment differential head, and a doctor blade drive assembly; the scraper adjusting micro-head is used for adjusting the relative positions of the scraper and the printing platform before printing starts, so that the top surfaces of the scraper and the printing platform are flush; the scraper is in sliding fit with the connecting component in the vertical direction; the scraper driving assembly is arranged on the connecting assembly and is connected with the scraper to drive the scraper to lift or put down, and the scraper can scrape materials when put down to control the thickness of the printing layer slurry.

In an alternative embodiment, the scraper comprises a blade holder slidably engaged with the connecting assembly and a blade connected to the blade holder.

In an alternative embodiment, the printing device further comprises one or more feeding assemblies, wherein the feeding assemblies comprise a feeding container, a squeezing piece and a feeding nozzle, the feeding nozzle is communicated with the feeding container through a feeding pipeline, the feeding container is used for storing printing paste, and the squeezing piece is used for discharging the printing paste in the feeding container to the feeding nozzle.

In an alternative embodiment, the scraper module further comprises a nozzle mounting piece which is in sliding fit with the connecting assembly in the second horizontal direction and is positioned on one side of the scraper module in the first horizontal direction, and the feeding nozzle is arranged on the nozzle mounting piece; the second moving module is connected with the nozzle mounting piece so as to drive the nozzle mounting piece to drive the feeding nozzle to move along the second horizontal direction.

In an alternative embodiment, the feed assembly includes at least two, each for supplying a different printing paste to the printing platform.

In an alternative embodiment, the printing device further comprises a residue recovery tank, wherein the residue recovery tank is arranged below the printing platform, and after the residue is scraped by the scraper module, the residue can flow into the residue recovery tank.

The beneficial effects of this application lie in: according to the printing device, the scraper module is arranged on the connecting component, the connecting component is used for connecting the feeding nozzle of the feeding component, the feeding nozzle is used for extruding feeding during printing, meanwhile, the scraper and the feeding nozzle are controlled to move together, when the feeding is completed, the printing liquid level can be smoothed, the leveling waiting time is not needed, and the printing efficiency is greatly improved; the slurry is directly paved on a printing platform, and printing can be performed by combining the slurry with the required paving and a small amount of slurry; the extrusion spreading combined with the scraping knife is scraped, and the application range of the viscosity of the sizing agent is wide; flexible feeding and capability of performing multi-material photo-curing printing.

Drawings

FIG. 1 is an overall schematic diagram of an embodiment of a photo-curing 3D printing device according to the present application;

FIG. 2 is a front view of a photo-curing 3D printing apparatus according to an embodiment of the present application after concealing a residual trough;

fig. 3 is an overall schematic diagram of a doctor blade feeding mechanism in an embodiment of a photo-curing 3D printing apparatus according to the present application;

fig. 4 is a front view of a doctor blade feeding mechanism in an embodiment of a photo-curing 3D printing apparatus according to the present application

FIG. 5 is a schematic diagram of a doctor blade module in an embodiment of a photo-curing 3D printing apparatus according to the present application;

FIG. 6 is a schematic diagram of a feed assembly in an embodiment of a photo-curing 3D printing apparatus according to the present application;

FIG. 7 is a flow chart of an embodiment of a printing method of the present application;

FIG. 8 is a viscosity profile of a zirconia ceramic printing paste having a solid content of 50 vol%;

FIG. 9 is an edge profile of a printed article printed by an embodiment of the present application;

FIG. 10 is a schematic illustration of applying an additional load to a printed article printed in accordance with example II of the present application;

FIG. 11 is a viscosity profile of a 58vol% solids zirconia ceramic printing paste;

fig. 12 is a display view of a print obtained by printing in the third embodiment of the present application.

Reference numerals: the printing machine comprises a frame 1, a printing bearing mechanism 2, a printing platform 21, a lifting assembly 22, a supporting plate 221, a lifting motor 222, a lifting screw 223, a sliding sleeve 224, a lifting guide 225, a light machine 3, a scraper feeding mechanism 4, a scraper module 41, a scraper 411, a knife holder 411a, a knife edge 411b, a scraper driving assembly 412, a cam 412a, a scraper motor 412b, a scraper guide 412c, a connecting assembly 42, a first sliding block 421, a first connecting plate 422, a second connecting plate 423, a first moving module 43, a first guide 431, a first driving belt 432, a first motor 433, a second moving module 44, a second guide 441, a second driving belt 442, a second motor 443, a nozzle mounting member 45, a residue recovery tank 5, a feeding assembly 6, a storage container 61, an extrusion member 62, a feeding nozzle 63 and a feeding pipeline 64.

Detailed Description

The invention will be described in further detail below with reference to the drawings by means of specific embodiments. Wherein like elements in different embodiments are numbered alike in association. In the following embodiments, numerous specific details are set forth in order to provide a better understanding of the present application. However, one skilled in the art will readily recognize that some of the features may be omitted, or replaced by other elements, materials, or methods in different situations. In some instances, some operations associated with the present application have not been shown or described in the specification to avoid obscuring the core portions of the present application, and may not be necessary for a person skilled in the art to describe in detail the relevant operations based on the description herein and the general knowledge of one skilled in the art.

Furthermore, the described features, operations, or characteristics of the description may be combined in any suitable manner in various embodiments. Also, various steps or acts in the method descriptions may be interchanged or modified in a manner apparent to those of ordinary skill in the art. Thus, the various orders in the description and drawings are for clarity of description of only certain embodiments, and are not meant to be required orders unless otherwise indicated.

The sequence numbers themselves, e.g. "first", "second", etc., for the modules herein are used only to distinguish between the described objects and do not have any sequential or technical meaning. The terms "coupled" and "connected," as used herein, are intended to encompass both direct and indirect coupling (coupling), unless otherwise indicated.

The application discloses photocuring 3D printing device, as shown in fig. 1, it is including printing and bear mechanism 2, UV ray apparatus 3, scraper feeding mechanism 4, and above-mentioned printing and bear mechanism 2, UV ray apparatus 3 and scraper feeding mechanism 4 can set up in a frame 1 in an integrated way.

As shown in fig. 1 and 2, the print supporting mechanism 2 is composed of a print platform 21 and a lifting assembly 22, the print platform 21 is a flat plate structure, and the upper surface of the print platform 21 is used for supporting printing paste and a printing piece formed by the printing paste. The lifting assembly 22 may be installed at the bottom of the printing platform 21 to drive the printing platform 21 to move in the vertical direction. For example, in the example of fig. 2, the lifting assembly 22 includes a support plate 221, a lifting motor 222 is fixedly mounted on the support plate 221, the lifting motor 222 is connected with a vertically disposed lifting screw 223 through a synchronous belt, a sliding sleeve 224 is screwed on the lifting screw 223, and the printing platform 21 is fixedly connected with the sliding sleeve 224; on this basis, the supporting plate 221 is fixed at the bottom of the frame 1 along the vertical direction, one side of the fixing plate is vertically provided with a lifting guide 225, the lifting guide 225 can be a guide member such as a sliding rod or a sliding groove, in this example, the lifting guide 225 is a vertically arranged sliding rail, and the side edge of the printing platform 21 is in sliding fit with the lifting guide 225; so that the printing platform 21 can be forced to move vertically along the elevation guide 225 to be elevated when the elevation screw 223 rotates. It should be appreciated that the lifting assembly 22 may also be, but is not limited to, a cylinder, ram, etc.

Referring to fig. 1 and 2, in the embodiment disclosed in the present application, a UV light engine 3 is fixed on top of a frame 1, which is located above a print carrier 2, and the UV light engine 3 has a light outlet, which is opposite to a print platform 21, so as to project UV light toward a direction where the print platform 21 is located.

Referring to fig. 1 to 5, the doctor feeding mechanism 4 is located between the printing platform 21 and the UV light machine 3, and specifically, as shown in fig. 3, 4 and 6, the doctor feeding mechanism 4 is composed of a doctor module 41, a connecting component 42, a first moving module 43 and a second moving module 44. The scraper module 41 is mounted on the connecting assembly 42, the connecting assembly 42 is connected to the first moving module 43, and the first moving module 43 drives the connecting plate to move on a horizontal plane. The second moving module 44 is installed at one side of the connecting assembly 42, the second moving module 44 is used for installing the feeding nozzle 63 of the feeding assembly 6, and the second moving module 44 can drive the feeding nozzle 63 to move along the horizontal plane, wherein the moving direction of the feeding nozzle 63 and the whole running direction of the connecting assembly 42 are mutually perpendicular in the horizontal plane.

In a specific example, with continued reference to fig. 3 and 4, the connection assembly 42 is formed by two parallel connection boards, and the two connection boards are connected by a first slider 421, for example, the first slider 421 may be installed at two ends of the two connection boards, so that the two connection boards can keep synchronous; for convenience of description, the direction in which the first moving module 43 drives the connection assembly 42 to move is defined as a first horizontal direction, and the two connection plates are defined as a first connection plate 422 and a second connection plate 423, respectively. In this example, the second connecting plate 423 is disposed on one side of the first connecting plate 422 in the first horizontal direction, the first moving module 43 is disposed at two ends of the first connecting plate 422 and the second connecting plate 423, specifically, the first moving module 43 includes a first guide member 431 extending along the first horizontal direction (for example, the first guide member 341 may be a sliding rail, a sliding rod, etc.), and a first driving assembly that controls the movement of the connecting assembly 42, where the sliding block in the connecting assembly 42 is slidably engaged with the first guide member 431, the first driving module includes a first driving belt 432 disposed along the first horizontal direction and a first motor 433 that drives the first driving belt 432 to move, and the first motor 433 is connected to the first driving belt 432 through a plurality of synchronous members (for example, synchronous belts, etc.) so as to drive the first driving belt 432 disposed at two sides of the connecting assembly 42 to operate synchronously, and the first driving belt 432 is fixedly connected to the first sliding block 421, so that when the first driving belt 432 rotates, the first sliding block 421 can be driven to operate along the first guide member 431, and thus drive the connecting assembly 42 to operate.

On the basis of the above example, as shown in fig. 3, 4 and 6, the second moving module 44 is disposed on the second connecting plate 423, and illustratively, the second connecting plate 423 is provided with a nozzle mounting member 45, the nozzle mounting member 45 is provided with a clamping slot to fix the feeding nozzle 63 of the feeding assembly 6, and the nozzle mounting member 45 and the connecting assembly 42 are slidingly engaged in a second horizontal direction, and the second horizontal direction is perpendicular to the first horizontal direction on a horizontal plane; the nozzle mount is located at one side of the scraper 411 in the first horizontal direction, and the feed nozzle 63 is provided on the nozzle mount 45; the second moving module 44 is connected with the nozzle mounting piece 45 to drive the feeding nozzle 63 to move along the second horizontal direction; the second moving module 44 includes a second guide member 441 (e.g., a sliding rail, a sliding rod, etc.) extending along a second horizontal direction, and a second driving assembly for controlling the movement of the nozzle, the nozzle mounting member 45 is slidably engaged with the second guide member 441, the second driving module includes a second driving belt 442 disposed along the second horizontal direction and a second motor 443 for driving the second driving belt 442 to move, and an output end of the second motor 443 is directly connected with the second driving belt 442 to drive the second driving belt 442 to operate, so that the nozzle mounting member 45 can be driven to operate along the second guide member 441 when the second driving belt 442 rotates, and further the feeding nozzle 63 is driven to move along the second horizontal direction.

It is to be understood that the first moving module 43 and the second moving module 44 are not limited to the structure disclosed in the above example, and the first moving module 43 and the second moving module 44 may also adopt other linear driving modules; for example, the cylinder, the screw motor, etc., can be adaptively selected and laid out in the art based on actual requirements, and the application is not limited too much.

In the example disclosed herein, referring to fig. 5, the doctor module 41 is composed of a doctor 411 and a doctor driving assembly 412, and the doctor 411 is slidably engaged with the connection assembly 42 and connected to the doctor 411 to drive the doctor 411 to move in a vertical direction. Referring to the example of fig. 5, in which the doctor blade is mounted on the first connection plate 422, in particular, the doctor blade driving assembly 412 includes a doctor blade guide 412c vertically disposed on the first connection plate 422, the doctor blade guide 412c may be, but is not limited to, a slide rail, a slide bar, etc., and the doctor blade 411 is slidably engaged with the doctor blade guide 412c in a vertical direction; more specifically, the doctor blade is composed of a blade holder 411a and a blade 411b, wherein the blade 411b is mounted at the bottom end of the blade holder 411 a; the blade holder 411a is slidably matched with the blade guide 412c, a driving through hole is formed in the middle of the blade holder 411a, the blade driving assembly 412 further includes a cam 412a disposed in the driving through hole and capable of vertically rotating, and a blade motor 412b for driving the cam 412a to move, when a protrusion of the cam 412a rotates upwards, the blade holder 411a can be lifted, and when the cam 412a rotates downwards, the blade holder 411a can be driven to move downwards, so that the blade 411 as a whole can move in a vertical direction. It should be understood that the doctor driving assembly 412 may also be configured by a cylinder, an oil cylinder, a screw motor, etc., which is not limited in this application.

Considering that the doctor blade drive assembly 412 can only adjust the vertical position of the doctor blade over a wide range, in some alternative designs, to more finely adjust the position of the blade edge 411b in the doctor blade, the doctor blade 411 includes a doctor blade adjustment differential head (not shown) for adjusting the relative positions of the doctor blade and the print platen before printing begins so that the doctor blade and the print platen top surface are flush. For example, the doctor blade adjustment differential head may be a micrometer adjustment differential head fixed to the first connection plate 422, which is not excessively limited in this application.

In some alternative designs, referring to fig. 1 and 2, the frame 1 is further provided with a remainder recycling tank 5, specifically, the remainder recycling tank 5 is a square tank with an open top, and is disposed below the printing platform 21.

In the embodiments disclosed herein, one or more feed assemblies 6 are mounted on the frame 1; referring to fig. 6, the present application provides a specific feeding assembly 6, where the feeding assembly 6 is composed of a storage container 61, an extrusion member 62 and a feeding nozzle 63, the feeding nozzle 63 is directly connected with the storage container 61 through a feeding pipe 64, and the extrusion member 62 is disposed in the middle of the feeding pipe 64 so that printing paste in the storage container 61 can be discharged to the feeding nozzle 63 through the storage pipe; as shown by way of example in fig. 6, the above-described squeeze 62 may employ a peristaltic pump that squeezes the feed conduit 64 through rollers to create a negative pressure within the feed conduit 64 to enable printing paste located within the reservoir 61 to be pumped toward the feed nozzle 63.

This application is in the during operation, because feed nozzle 63 and scraper 411 all are located coupling assembling 42, therefore when printing, can order about coupling assembling 42 along first horizontal direction towards the one side motion that is provided with feed nozzle 63, order about feed nozzle 63 simultaneously along the second horizontal direction and remove, because first horizontal direction perpendicular to second horizontal direction, in this process, through the removal route of first removal module 43 and second removal module 44 control feed nozzle 63 and coupling assembling 42, can make the whole printing area of feed nozzle 63 route, realize extruding the feed, simultaneously, scraper 411 also can be synchronous will print the thick liquids and strickle, control the thickness of printing thick liquids, need not the levelling latency.

In operation, the specific printing method is shown in fig. 7, and comprises the following steps:

step S101: establishing a printing model with three-dimensional space coordinates; establishing a virtual printing model of a piece to be printed through computer modeling software, preprocessing the printing model, and generating a frame model which is enclosed outside the printing model in the horizontal direction and is equal to the highest point of the printing model in the vertical direction according to the size of the printing model; and combining the frame model and the printing model into one three-dimensional model.

When the step is carried out, the three-dimensional space coordinates of the printing model are determined based on the size of the required printing part, when the printing model is established, a printing area corresponding to the printing part to be printed and a frame model for supporting the printing part are arranged in the printing model, the frame model is enclosed on the outer side of the printing model, the height of the frame model is equal to the height of the printing model, and the frame model is enclosed on the periphery of the printing model.

According to the model size of the printing piece, a frame for protecting printing slurry is designed, and the printing piece is surrounded by the frame; and the height of the designed frame is equal to the height of the highest point of the printing piece. In the printing process, the frame can be synchronously printed and formed along with the printing piece, the frame can be used for limiting the area of the printing piece, slurry in the printing area is reserved, the protective frame model surrounds the piece to be printed, and a liquid level support is formed for the layer to be printed in the printing area.

Wherein the thickness of the frame model is determined based on the viscosity of the printing paste and the strength of the printed green body (i.e., the printed article after printing but without post-treatment), preferably, the model of the frame is 0.5 to 5mm.

Step S102: slicing the printing model, dividing the printing model into a plurality of slicing files corresponding to the layers to be printed in the vertical direction, and setting printing parameters of each layer to be printed based on the sections (slicing patterns) of the printing area and the frame area on each slicing file.

In this step, the printing model is divided into a plurality of slice files continuously arranged in the vertical direction according to the performance of the printing paste by using computer modeling software, the printing model is mapped above the printing platform 21 according to the three-dimensional space coordinates of the printing model, a plurality of layers to be printed which are in one-to-one correspondence with the slice files are preset above the printing platform 21, and the printing parameters of the corresponding printing layers are determined according to the sections of the printing area and the frame area on each slice file.

Illustratively, the above-described printing parameters may include one or more of the following: corresponding to the print pattern (i.e., the cross-sectional pattern of the slice file), layer thickness (height of the single layer to be printed), exposure intensity, and exposure time; the feed nozzle 63 can then plan its path of movement in the first and second directions and control the feed based on the printing parameters.

Step S2: printing preparation: the height of the printing platform 21 is adjusted through the lifting mechanism, so that the surface of the printing platform is positioned at the focus of the UV light machine 3; the differential head is adjusted by the doctor blade drive assembly 412 and the trimming doctor blade so that the bottom of the doctor blade is level with the top with the platform.

Step S3: single-layer printing: after the doctor blade position is adjusted, the printing platform 21 descends by the height of one layer to be printed, the feeding nozzle 63 moves in the second horizontal direction and extrudes printing paste based on the printing parameters of the layer to be printed, and meanwhile, the connecting component 42 moves towards the side provided with the feeding nozzle 63 in the first horizontal direction, so that the doctor blade module 41 moves from an initial position to a final position in the first horizontal direction; controlling the feeding nozzle 63 to spread materials in the layer to be printed according to the need by cooperatively controlling the movement of the feeding nozzle in the first horizontal direction and the second horizontal direction; the thickness of the layer to be printed is controlled by the scraper 411 moving along the first horizontal direction, and the residual materials are scraped off by the scraper 411 and then flow into the residual material collecting tank 5 at the bottom of the printing platform; and curing the printing paste, and exposing the paste scraped by the scraper 411 according to the slice pattern of the slice file corresponding to the layer to be printed by the UV light machine as required to cure the paste. The scraper feeding mechanism 4 is reset.

In this step, the range of the required feeding is determined based on the position of the layer to be printed on the printing platform, and the movement paths of the feeding nozzle 63 in the first horizontal direction and the second horizontal direction are determined according to the printing parameters, and the feeding nozzle 63 moves according to the movement paths and extrudes the printing paste, for example, the movement path of the feeding nozzle 63 can be determined based on the existing path planning algorithm (such as linear path planning, curve path planning, path planning based on graph theory, path planning based on genetic algorithm, etc.) and the feeding control technology, and the feeding rate is calculated according to the required printing layer thickness and the movement rate of the feeding nozzle, so as to realize accurate feeding.

In this step, the movement paths of the connection assembly 42 and the feeding nozzle 63 are all performed according to the input printing parameters, and since the feeding nozzle 63 is mounted on the connection assembly 42, the feeding nozzle 63 can synchronously move along the first horizontal direction along with the connection assembly 42, and at the same time, the feeding nozzle 63 can also move along the second horizontal direction, so that when the connection assembly 42 moves along the preset path in the first horizontal direction, the feeding nozzle 63 can also move along the whole area of the layer to be printed. In this process, since the doctor 411 and the feed nozzle 63 move synchronously, and the feed nozzle 63 is located in front of the movement direction of the doctor 411, the functions of leveling the liquid surface, precisely controlling the layer thickness, and removing the surplus slurry can be simultaneously realized in the feeding process, and the surplus slurry can be scraped off the feed platform by the doctor 411, thereby entering the surplus slurry recovery tank 5.

In this step, exposure parameters may be determined based on the composition of the printing paste and the slice pattern at the time of performing the slicing process as part of the model slice parameter setting; specifically, the UV light machine 3 exposes the printing paste scraped by the doctor 411 according to a slice pattern according to the exposure intensity and exposure time set by the printing parameters, so as to cure the printing paste, thereby obtaining a cured layer, and the cured layer includes a cured pattern corresponding to the slice patterns of the printing model and the frame model.

Step S4: repeating the step of single-layer printing until printing is completed; removing the frame to obtain a printing piece; and cleaning, drying, post-curing and the like are carried out on the printing piece.

In some embodiments, the application may also perform multi-material photo-curing printing, that is, two or more materials are used on one printing piece, and when performing multi-material photo-curing printing, two or more feeding components 6 may be installed on the frame 1 based on the type of printing paste required during printing, specifically, the number of feeding components 6 is matched with the weight of the required printing paste, and the feeding nozzles 63 of the feeding components 6 are installed on the nozzle mounting piece 45 side by side.

In the traditional sinking type photo-curing 3D printing device, the printing platform is required to be completely immersed into the slurry tank to supplement printing slurry; therefore, a single printing can print only one printing paste, and it is difficult to realize printing of a plurality of materials.

In the case of multi-material printing, the overall printing steps are similar to steps S1 to S6 described above, including the following additional steps, in particular:

in step S1: the step of establishing the print model with three-dimensional space coordinates further comprises the steps of: adding material properties to the print model; specifically, dividing a printing area in a printing model, and dividing the printing area into a plurality of material blocks corresponding to printing paste one by one according to required printing paste; for example, when printing with two materials, at least two print tiles need to be separated within the print area.

When slicing is carried out on the printing model, the printing parameters of each layer to be printed are determined based on the material properties of each region of the material block in the corresponding slicing file; more specifically, the printing parameters determine the type of printing paste in the corresponding area of the layer to be printed according to the corresponding slice pattern of each material block in the slice file, that is, when each feeding nozzle 63 passes through the area corresponding to the corresponding material block, the corresponding feeding nozzle 63 is started.

Specifically, when the step of single-layer printing in step S3 is performed, when the plurality of supply nozzles 63 pass through the layer to be printed along the second horizontal direction, if the passed area is any area corresponding to the material block in the corresponding slice file, at this time, the supply nozzles 63 corresponding to the material block start to supply according to the printing parameters, and the other nozzles stop to supply.

In step S3, in the step of curing on demand: respectively irradiating areas corresponding to all material blocks in the layer to be printed, and adjusting exposure parameters (ultraviolet light power, exposure time length and the like) of the UV light machine 3 based on the characteristics of printing paste in the areas, wherein the exposure parameters can be obtained when the printing model is sliced; for example, different exposure parameters may be set based on a manual or algorithm, depending on the slice pattern of the material block in the slice file.

According to the printing device, the connecting component 42 is arranged, so that the scraper mounting and feeding nozzles 63 can be simultaneously mounted on the connecting component 42, printing slurry can be synchronously scraped in the printing feeding process, and further liquid level detection, feedback and leveling waiting time are not needed, so that the printing speed is greatly improved, and the printing time benefit is improved; on the other hand, the thickness of the printing paste is controlled by the extrusion feeding matched with the scraper, the viscosity of the printing paste is not limited, and the printing paste is suitable for printing pastes with various viscosities.

In the conventional submerged photo-curing printing device, a sufficient amount of printing paste needs to be filled in the resin tank in advance, and the printing paste needs to be continuously lowered through the printing platform to be replenished during printing. Compared with the traditional sinking type photocuring printing device, the printing device has the advantages that printing paste does not need to be filled in advance in the printing mode of extrusion feeding, the outer frame is designed to support the liquid level of the printing paste, and the printing paste can be remarkably saved. And traditional submerged photocuring printing device still need set up liquid level detection and feedback system, and the structure is comparatively complicated. The liquid level detection and feedback system is not needed, and the liquid level detection and feedback system is simple in structure and low in cost.

The method has the characteristic of high morphology fidelity. Because the slurry generally has certain viscosity and surface tension, when the viscosity of the slurry is not low enough and the leveling waiting time is not long enough, the edge of the printing piece printed by adopting the traditional sinking type photo-curing can be deformed to a certain extent, and the appearance is distorted. The printing device and the printing method can well provide liquid level support for the printing piece because the outer frame generated by synchronous printing is used as the slurry fence, so that the printing piece has no edge deformation and high shape fidelity.

The printing device is suitable for printing of various slurries, has low leveling property and viscosity requirements on the slurries, can plan printing parameters according to different slurries, switch printing slurries, realize accurate feeding, reduce material waste, reduce printing cost and improve printing benefit.

For ease of explanation of the present application, the present application provides the following specific examples:

embodiment one:

a homemade 50vol% solids zirconia ceramic printing paste was used, the viscosity profile of which is shown in fig. 8, which has suitable rheological properties for printing with a conventional submerged photo-curing printer.

The photo-curing 3D printing device, the printing method and the traditional sinking photo-curing printer disclosed by the application are used for printing the printing paste, and the morphology diagram of the finally obtained printing piece is shown in fig. 9.

Fig. 9a is an edge profile of a printed article obtained by using a conventional submerged photo-curing printer, and fig. 9b is an edge profile of a printed article obtained by using the photo-curing 3D printing device and the printing method disclosed in the present application. As can be seen from fig. 9a and 9b, the edge of the printed piece obtained by the conventional submerged photo-curing printer has a phenomenon of edge collapse and shape distortion to a certain extent; the edge of the printing piece prepared by the photo-curing 3D printing device and the printing method is flat and has no shape distortion. The photo-curing 3D printing device and the printing method provided by the invention are adopted to prepare the printing piece, and the printing piece has the characteristics of no edge deformation and high shape fidelity.

Compared with the traditional sinking type photocuring printing method, the photocuring 3D printing method disclosed by the application is used for completing the same printing piece, a large amount of slurry is required to be poured into the slurry cylinder in the traditional sinking type photocuring printing method, and the method disclosed by the application does not need to pour the slurry into the slurry cylinder completely, so that the consumption of printing the slurry can be effectively reduced. Meanwhile, by the photocuring 3D printing method, leveling waiting time is not needed, and printing efficiency can be effectively improved.

Embodiment two:

with the method disclosed herein, printing is performed using two printing pastes simultaneously. Wherein, printing paste A is rigid photosensitive resin, and printing paste B is flexible photosensitive resin. For ease of testing, when the print model is built, the lower layer of the design model is print paste a (white) and the upper layer of the model is print paste B (black).

Applying an additional load to the whole finally obtained printing piece in the vertical direction for testing; as a result, as shown in fig. 10, it was seen that the black layer of the print was significantly deformed, while the white layer of the print was not visibly deformed; indicating that the material properties of the upper and lower sides of the print are different. Further, it is demonstrated that the photo-curing 3D printing device and the printing method provided by the application can perform multi-material printing.

Embodiment III:

printing by adopting self-made zirconia ceramic printing slurry with the solid content of about 58 vol%; the viscosity profile of the printing paste is shown in fig. 11.

The printing paste is printed by using the photocuring 3D printing device and the printing method disclosed by the application, and finally the obtained printing piece is cleaned, dried, degreased and sintered, as shown in fig. 12. Comparison with example one shows that the present application can accommodate printing pastes of various viscosities.

The foregoing description of the invention has been presented for purposes of illustration and description, and is not intended to be limiting. Several simple deductions, modifications or substitutions may also be made by a person skilled in the art to which the invention pertains, based on the idea of the invention.

Claims

1. A photo-curing 3D printing method, characterized in that printing is performed by using a photo-curing 3D printing device, the photo-curing 3D printing device comprising:

the printing platform is used for bearing printing pieces and printing slurry;

the photocuring 3D printing method comprises the following steps of:

model pretreatment: generating a frame model which is enclosed outside the printing model in the horizontal direction and has the same height as the highest point of the printing model in the vertical direction according to the size of the printing model; combining the frame model and the printing model into a three-dimensional model, slicing the three-dimensional model to obtain a plurality of slice files, setting printing parameters for each slice file, and confirming the position of a layer to be printed on the printing platform based on the slice files;

And repeating the single-layer printing step until printing is completed.

2. The light-curable 3D printing method according to claim 1, wherein in the slice file, the slice pattern of the frame model surrounds the periphery of the slice pattern of the print model; and/or the slice pattern of the frame model is square or circular.

3. The photo-curing 3D printing method according to claim 1, wherein the thickness of the frame model is determined based on the viscosity of the printing paste and the strength of the printed green body, and the thickness of the frame model is 0.5 to 5mm.

4. The photocurable 3D printing method of claim 1 wherein the printing parameters include one or more of a print pattern, a layer thickness, an exposure intensity, and an exposure time corresponding to each of the layers to be printed.

5. The method of photo-curing 3D printing of claim 1, wherein the step of on-demand tiling within the layer to be printed by coordinated control of the movement of the feed nozzle in a first horizontal direction and a second horizontal direction comprises:

6. The photo-curable 3D printing method according to claim 1, wherein the step of on-demand exposure comprises: and exposing the printing paste scraped by the scraper according to the exposure intensity and the exposure time set by the printing parameters through a UV (ultraviolet) ray machine and curing the printing paste according to a slice pattern to obtain a cured layer, wherein the cured layer comprises a cured pattern corresponding to the slice patterns of the printing model and the frame model.

7. The light-curable 3D printing method according to any one of claims 1 to 6, wherein the number of the feed assemblies corresponds one-to-one to the kind of printing paste when printing with at least two kinds of printing paste, wherein:

8. A photo-curing 3D printing device, comprising:

9. The light-curable 3D printing device of claim 8, wherein the doctor blade module comprises a doctor blade, a doctor blade adjustment differential head, and a doctor blade drive assembly; the scraper adjusting micro-head is used for adjusting the relative positions of the scraper and the printing platform before printing starts, so that the top surfaces of the scraper and the printing platform are flush; the scraper is in sliding fit with the connecting component in the vertical direction; the scraper driving assembly is arranged on the connecting assembly and is connected with the scraper to drive the scraper to lift or put down, and the scraper is used for scraping when put down to control the thickness of the printing layer slurry.

10. The light curable 3D printing device of claim 9, wherein the doctor blade comprises a blade seat and a blade, the blade seat being in sliding engagement with the connection assembly, the blade being connected to the blade seat.

11. The light curable 3D printing device of claim 8, further comprising one or more of the feed assemblies, the feed assemblies including a feed reservoir, an extrusion, and the feed nozzle, the feed nozzle in communication with the feed reservoir through a feed conduit, the feed reservoir for storing printing paste, the extrusion for causing printing paste within the feed reservoir to be discharged toward the feed nozzle.

12. The light-curable 3D printing device of claim 8, further comprising a nozzle mount slidably engaged with the connection assembly in the second horizontal direction and located on one side of the doctor blade module in the first horizontal direction, the feed nozzle being disposed on the nozzle mount; the second moving module is connected with the nozzle mounting piece so as to drive the nozzle mounting piece to drive the feeding nozzle to move along the second horizontal direction.

13. The light curable 3D printing device of claim 8, wherein the feed assembly comprises at least two, each for supplying a different printing paste to a printing platform.

14. The light-cured 3D printing device of claim 8, further comprising a cullet recycling bin disposed below the printing platform, the cullet recycling bin being capable of flowing cullet into the cullet recycling bin after the cullet is scraped by the scraper module.