CN110856978B

CN110856978B - 3D printing system and 3D printing method

Info

Publication number: CN110856978B
Application number: CN201810939224.7A
Authority: CN
Inventors: 卢国; 魏国军; 周扬
Original assignee: Suzhou University; SVG Tech Group Co Ltd
Current assignee: Suzhou University; SVG Tech Group Co Ltd
Priority date: 2018-08-17
Filing date: 2018-08-17
Publication date: 2022-08-05
Anticipated expiration: 2038-08-17
Also published as: CN110856978A

Abstract

A3D printing system comprises a feeding mechanism, a printing platform and an imaging mechanism, wherein the feeding mechanism comprises a printing conveyor belt and a plurality of feeding tanks, the plurality of feeding tanks can discharge a plurality of printing materials on the printing conveyor belt layer by layer, and the printing conveyor belt can convey the printing materials onto the printing platform; the printing platform comprises a carrying plate, a printing head and a film pressing mechanism, wherein the carrying plate is arranged below the printing conveyor belt and is used for carrying and positioning a printing material; the printing head is arranged above the printing conveyor belt, and the film pressing mechanisms are arranged on two sides of the carrying plate and are positioned above the printing conveyor belt; the imaging mechanism can generate a projection pattern for irradiating the printing material, and the projection pattern is irradiated on the printing material on the carrying plate, so that the printing material is solidified into a printing entity on the printing platform. When printing on printing the conveyer belt, compress tightly the printing conveyer belt through press mold mechanism, keep printing the steady of conveyer belt, help improving the printing precision. The invention further relates to a 3D printing method.

Description

3D printing system and 3D printing method

Technical Field

The invention relates to the technical field of 3D printing, in particular to a 3D printing system and a 3D printing method.

Background

3D printing is one of rapid prototyping technologies, is a technology for constructing an object by using a bondable material such as powdered metal, plastic or photosensitive resin and the like in a layer-by-layer printing mode on the basis of a digital model file, and has important application in high-end fields such as aerospace, biomedical, weaponry, automobile, molds and the like.

Particularly in the field of biological medical treatment, the 3D printing technology provides a new flexible preparation method for biochips and biochemical devices, also provides a new research means and platform for the fields of biological materials and artificial organs, and realizes the manufacture of complex 3D carrier supports. However, the existing 3D printing technology still has difficulty in meeting application requirements in terms of printing precision and printing breadth. Aiming at the field of biological application, the 3D printing technology still does not effectively solve the problem that the printing precision and the printing size cannot be considered at the same time. On one hand, the stereolithography based on two-photon or laser direct writing can realize printing of complex structures as small as 0.1 micron, but is limited by the printing size (less than several hundred microns) and is not suitable for biochip fabrication. On the other hand, the stereolithography based on projection type is limited by the printing precision (greater than 30 μm) and is difficult to satisfy the requirement of fabricating the micro structure in the biochip. Currently, the lateral resolution of commercial 3D printers is only 50 microns, and the depth resolution is about 50-100 microns. Meanwhile, the surface roughness of the biochip printed by the existing 3D printing technology is large, and the biochip is not beneficial to biological detection. On the other hand, considering the biodiversity, a single material cannot meet the requirements of the design and fabrication of the biological device.

Disclosure of Invention

The invention aims to provide a 3D printing system and a 3D printing method, which can realize mixed printing of various materials and meet the requirement of the biomedical field on printing precision.

The technical problem to be solved by the invention is realized by adopting the following technical scheme.

A3D printing system comprises a feeding mechanism, a printing platform and an imaging mechanism, wherein the feeding mechanism comprises an unwinding disc, a driving roller and a plurality of feeding tanks, a printing conveyor belt is wound on the unwinding disc, the plurality of feeding tanks can discharge a plurality of printing materials onto the printing conveyor belt layer by layer, and the driving roller drives the printing materials to be conveyed onto the printing platform;

the printing platform comprises a carrying plate, a printing head and a film pressing mechanism, wherein the carrying plate is arranged below the printing conveyor belt and used for carrying and positioning a printing material; the printing head is arranged above the printing conveyor belt and is used for printing products; the film pressing mechanism is arranged on two sides of the carrying plate and positioned above the printing conveyor belt and is used for fixedly pressing the printing conveyor belt;

the imaging mechanism can generate a projection pattern for irradiating the printing material, and the projection pattern is irradiated on the printing material on the carrying plate, so that the printing material is solidified into a printing entity on the printing platform.

In a preferred embodiment of the present invention, the supply tanks include a first supply tank, a second supply tank, and a third supply tank arranged in sequence, and the first supply tank, the second supply tank, and the third supply tank discharge the same printing material, or two of the printing materials, or all of the printing materials are different; the feeding mechanism further comprises a first scraper, a second scraper and a third scraper, wherein the first scraper is used for scraping printing materials discharged by the first feeding tank evenly, the second scraper is used for scraping printing materials discharged by the second feeding tank evenly, and the third scraper is used for scraping printing materials discharged by the third feeding tank evenly.

In a preferred embodiment of the present invention, the first scraper is disposed behind the first feeding tank, the second scraper is disposed behind the second feeding tank, the third scraper is disposed behind the third feeding tank, and the cutting edges of the first scraper, the second scraper, and the third scraper are disposed opposite to the printing conveyer.

In a preferred embodiment of the present invention, the 3D printing system further includes a winding mechanism disposed behind the printing platform, the winding mechanism includes a residue curing lamp and a winding disc, the residue curing lamp is disposed above the printing and conveying belt and can emit uv light to cure the printing material remaining after printing, and the winding disc is used for winding the printing and conveying belt.

In a preferred embodiment of the present invention, two ends of the printing and conveying belt are respectively wound on the unwinding disc and the winding disc, and after the driving roller is disposed on the unwinding disc, the driving roller drives the printing and conveying belt to sequentially pass through the feeding tank, the printing platform and the residual material curing lamp and move towards a direction close to the winding disc.

In a preferred embodiment of the present invention, the imaging mechanism comprises a light source, a beam shaper, a DMD light modulator, a plurality of mirrors, and a projection lens, the beam shaper being configured to shape a light beam emitted by the light source; the DMD optical modulator is used for generating a planar projection pattern from the shaped light beam; the reflector is used for reflecting the projection pattern to the projection lens; the projection lens is arranged opposite to the printing platform and can project the projection pattern on the printing material.

In a preferred embodiment of the present invention, the imaging mechanism further includes a computer and a controller, the computer is configured to provide displacement data and divide the exposure data into a series of striped pattern files, and send the displacement data and the pattern files to the controller, the controller uploads the pattern files to the DMD light modulator in time sequence, so that the DMD light modulator generates a projection pattern, and the controller controls the projection lens to move in a direction close to the printing conveyer belt through the displacement data.

In a preferred embodiment of the present invention, the imaging mechanism further includes a CCD monitoring system and a photodetector, the CCD monitoring system is configured to monitor a printing condition of the printing platform and a topography and a layer thickness of a current printing layer, and send the printing data to the computer, the computer can calculate a printing precision through the printing data, and the controller controls the CCD monitoring system and the projection lens to move synchronously through displacement data;

the photoelectric detector is used for collecting light reflected by the surface of the printing material and sending generated shape data to the controller, and the controller adjusts the projection focal length of the projection lens according to the shape data.

In a preferred embodiment of the present invention, the imaging mechanism further comprises a yellow light source, the yellow light source emits light which is reflected to the projection lens through the reflector, and the CCD monitoring system monitors the heights of the four corners of the carrier plate and sets the layer thickness of the pre-printed material to ensure parallelism between the surface of the printhead and the upper surface of the pre-printed material.

A3D printing method, the 3D printing method comprising the steps of:

providing a feeding mechanism, wherein the feeding mechanism comprises a printing conveyor belt, a feeding tank and a scraper, the feeding tank can discharge printing materials onto the printing conveyor belt, and the scraper can scrape the printing materials evenly;

providing a printing platform, wherein the printing platform comprises an object carrying plate, a printing head and a film pressing mechanism, conveying a printing material on a printing conveyor belt onto the object carrying plate, and controlling the film pressing mechanism to press downwards to perform 3D printing;

providing an imaging mechanism, wherein the imaging mechanism comprises a CCD monitoring system;

firstly, monitoring the heights of four corners of the carrying plate by using the CCD monitoring system, and setting the layer thickness of a pre-printed material so as to ensure that the surface of a printing head is parallel to the upper surface of the pre-printed material;

then, the image forming mechanism is used for generating a projection pattern, the projection pattern is made to irradiate the printing material on the carrying plate, and the printing material is solidified into a printing entity on the printing platform.

The feeding mechanism of the 3D printing system comprises a first feeding tank, a second feeding tank and a third feeding tank, printing materials provided by the feeding tanks are discharged onto a printing conveyor belt layer by layer and are spread and leveled layer by layer through scrapers, the printing conveyor belt conveys the printing materials onto a carrying plate of a printing platform, the printing conveyor belts on two sides of the printing platform are pressed tightly through a film pressing mechanism, and a projection pattern is generated by an imaging mechanism and projected onto the printing materials of the printing platform to enable the printing materials to be solidified into a printing entity. Wherein, when printing on printing the conveyer belt, compress tightly the printing conveyer belt through press mold mechanism, keep printing the steady of conveyer belt, help improving the printing precision. Through the yellow light source, the height of four angles of the object carrying plate is monitored, and a layer of material is pre-printed, so that the surface of the printing head and the upper surface of the pre-printed material are kept parallel, and the printing precision is further improved. The 3D printing system disclosed by the invention realizes mixed printing of multiple materials by coating the printing materials layer by layer, and has extremely great significance for biological application.

Drawings

Fig. 1 is a schematic structural diagram of a 3D printing system according to the present invention.

Fig. 2 is a schematic flow chart of a 3D printing method according to the present invention.

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description of the embodiments, structures, features and effects of the 3D printing system and the 3D printing method according to the present invention with reference to the accompanying drawings and preferred embodiments is as follows:

fig. 1 is a schematic diagram of the structure of a 3D printing system 10 of the present invention. As shown in fig. 1, a 3D printing system 10 includes a feeding mechanism 12, a printing platform 14, an imaging mechanism 16, and a receiving mechanism 18.

Specifically, the feeding mechanism 12 includes a payout reel 121, a drive roll 122, a print ribbon 123, a supply tank 124, and a doctor blade 125, wherein the supply tank 124 includes a first supply tank 124a, a second supply tank 124b, and a third supply tank 124c, and the doctor blade 125 includes a first doctor blade 125a, a second doctor blade 125b, and a third doctor blade 125 c.

Print ribbon 123 is wound onto take-off spool 121 and supply tank 124 can discharge multiple printing materials onto print ribbon 123 in layers and drive the printing materials onto print platform 14 via drive roller 122. The print belt 123 is made of a material that is light-transmissive, i.e., light can pass through the print belt 123 as a print carrier. In the present embodiment, the print conveyance belt 123 is disposed along the horizontal direction. In the present embodiment, the driving roller 122 includes two driving rollers which are symmetrical up and down, and both surfaces of the printing conveyance belt 123 are in contact with the two driving rollers, respectively.

A first supply tank 124a, a second supply tank 124b, and a third supply tank 124c are provided above the print carriage 123 for storing the printing material. In this embodiment, the printing materials provided by the first supply tank 124a, the second supply tank 124b and the third supply tank 124c may be the same printing material, or may be three different printing materials, or two of the printing materials provided may be the same, and the other printing material provided may be different.

Specifically, the bottom of each feed jar is equipped with the bin outlet, and the bin outlet is just to printing conveyer belt 123, still is equipped with the piston on each feed jar, and printing material locates the below of piston. In this embodiment, each supply tank may press the marking material through a piston, causing the marking material to be discharged through a discharge opening onto the print transport belt 123. Note that the printing material on the print belt 123 needs to be scraped into a flat film shape, and in order to ensure that the area of the film is large enough, each supply tank is moved in the width direction of the print belt 123 when discharging the printing material, so that the printing material is discharged onto the print belt 123 in a strip shape.

The first scraper 125a is disposed behind the first supply tank 124a and above the print belt 123, and is used for scraping the printing material discharged from the first supply tank 124 a. A second scraper 125b is disposed behind the second supply tank 124b and above the print belt 123, and is used for scraping the printing material discharged from the second supply tank 124 b. A third scraper 125c is provided behind the third supply tank 124c and above the print belt 123, and is used to scrape the printing material discharged from the third supply tank 124c flat. The first scraper 125a, the second scraper 125b and the third scraper 125c have their cutting edges disposed opposite to the printing conveyer belt 123, and the length direction of the cutting edge of each scraper is parallel to the width direction of the printing conveyer belt 123.

In this embodiment, each scraper is movable toward the print belt 123 until a predetermined distance is reached, and the squeegeeing material is wiped flat as the print belt 123 carries the print material past the scraper. Of course, the method of scraping the printing material smoothly is not limited to the above-described method, and for example, the printing material is scraped by driving the respective scrapers to reciprocate along the longitudinal direction of the printing conveyor belt 123 without moving the printing conveyor belt 123.

The printing platform 14 includes a carrier plate 141, a print head 142, and a film pressing mechanism 143, and the carrier plate 141 is disposed below the printing conveyor 123 and is used for carrying and positioning a printing material. The carrier plate 141 is made of a material that is light-permeable, i.e., light can pass through the carrier plate 141. When 3D printing is performed, the printing conveyer belt 123 may convey a printing material to the loading plate 141.

The print head 142 is disposed above the print belt 123 for printing the product. The print surface of the print head 142 is disposed opposite the carrier plate 141, and the print head 142 is movable toward and away from the print carriage 123. When 3D printing is performed, the print head 142 is moved in the direction of the print belt 123 until the printing surface of the print head 142 comes into contact with the printing material.

The film pressing mechanism 143 is disposed on two sides of the loading plate 141 and above the printing conveyor belt 123, and is used for fixing and pressing the printing conveyor belt 123. When 3D printing is carried out, the printing material is conveyed to the loading plate 141, the film pressing mechanism 143 moves towards the printing and conveying belt 123 to press the printing and conveying belt 123 tightly, and the printing and conveying belt 123 is kept flat and stable in the printing process.

In this embodiment, 3D printing system 10 still includes winding mechanism 18, and after printing platform 14 was located to winding mechanism 18, winding mechanism 18 included incomplete material curing lamp 181 and rolling dish 182, and incomplete material curing lamp 181 is located and is printed conveyer belt 123 top, can send the remaining printing material after the ultraviolet curing prints. The take-up reel 182 is used to take up the print carriage 123. In this embodiment, the winding disc 182 is connected to a motor, and the winding disc 182 is driven by the motor to uniformly wind the printing conveyer 123.

Wherein, both ends of the printing conveyer 123 are respectively wound on the unwinding reel 121 and the winding reel 182, and after the driving roller 122 is arranged on the unwinding reel 121, the driving roller 122 drives the printing conveyer 123 to move towards the direction close to the winding reel 182 sequentially through the feeding tank, the printing platform 14 and the residue curing lamp 181.

The imaging mechanism 16 is disposed below the feeding mechanism 12, and the imaging mechanism 16 can generate a projection pattern for irradiating the printing material, so that the projection pattern is irradiated on the printing material on the carrying plate 141, and the printing material is solidified into a printing entity on the printing platform 14. In this embodiment, the imaging mechanism 16 includes a light source 160a, a beam shaper 161, a DMD light modulator 162, a plurality of mirrors 163, a projection lens 164, a CCD monitoring system 165, a controller 166, a computer 167, a photodetector 168, a focusing light source 160b, and a yellow light source 169.

The light source 160a is used to provide printing light required for printing. In the present embodiment, the light source 160a of the imaging mechanism 16 is, for example, a UV light source, but not limited thereto.

The beam shaper 161 is used to shape the light emitted by the light source 160 a. In this embodiment, the beam shaper 161 can shape the light beam into a flat-topped beam.

The DMD light modulator 162 generates a planar projection pattern from the shaped light beam. In this embodiment, the DMD light modulator 162 may display a print pattern, so that a projection pattern is generated when the shaped light passes through the DMD light modulator 162.

The mirror 163 is used to reflect the shaped light to the DMD light modulator 162 and to reflect the projection pattern to the projection lens 164.

The projection lens 164 is disposed opposite to the printing platform 14, and the projection lens 164 is disposed below the object plate 141, so that the projection lens 164 can project the projection pattern on the printing material.

The CCD monitoring system 165 is configured to monitor the printing condition of the printing platform 14 and the topography and layer thickness of a current printed layer, and send print data to the computer 167, the computer 167 can calculate the printing precision according to the print data, and the controller 166 controls the CCD monitoring system 165 and the projection lens 164 to move synchronously according to displacement data; the photodetector 168 is configured to collect light reflected by the surface of the printing material and send the generated profile data to the controller 166, and the controller 166 adjusts the projection focal length of the projection lens 164 according to the profile data.

It should be noted that, before 3D printing, the loading plate 141 may be in an inclined state, and the print head 142 may press the print belt 123. It is desirable to preprint a layer of material on the carrier plate 141 to ensure that the surface of the print head 142 is parallel to the top surface of the preprinted material. Specifically, the heights of the four corners of the loading plate 141, i.e., the inclinations of the loading plate 141, are first monitored by the CCD monitoring system 165. The computer then sets the layer thickness of the pre-printed material by tilting the carrier plate 141 to ensure that the surface of the print head 142 is parallel to the upper surface of the pre-printed material.

The computer 167 is used to provide displacement data and to segment the exposure data into a series of striped pattern files and to send the displacement data and pattern files to the controller 166. In this embodiment, the computer 167 may divide the exposure data into a series of stripe pattern files (BMP files) having widths equal to or smaller than the width pixels of the DMD light modulator 162.

The controller 166 is used to control the various components of the imaging mechanism 16 to coordinate, for example, data import, motion synchronization control, focus control, etc. Specifically, the controller 166 uploads the pattern file to the DMD light modulator 162 according to the received pattern file timing sequence, and at this time, the DMD light modulator 162 may sequentially display the print pattern, so that the shaped light beam generates a corresponding projection pattern when passing through the DMD light modulator 162. The controller 166 also controls the projection lens 164 to move along the length direction of the print carriage 123 according to the received displacement data. In this embodiment, the imaging mechanism 16 of the present invention uses a timing synchronization technique, each time the DMD light modulator 162 sends out a projection pattern for printing, the pattern file translates a certain pixel on the DMD light modulator 162 and correspondingly sends out another pair of projection patterns, and the controller 166 controls the projection lens 164 to move a certain distance according to the received displacement data.

The photodetector 168 is used for collecting light reflected by the surface of the printing material and sending the generated profile data to the controller 166, and the controller 166 adjusts the projection focal length of the projection lens 164 according to the profile data.

The focusing light source 160b is used to provide a light source before 3D printing, thereby adjusting the focal length of the projection lens 164. The light emitted by the focusing light source 160b is reflected to the projection lens 164 and the photodetector 168 through the plurality of reflectors 163, the projection lens 164 projects on the surface of the printing conveyer 123, meanwhile, the photodetector 168 collects the light reflected by the surface of the printing conveyer 123, and sends the generated topographic data to the controller 166, and the controller 166 adjusts the projection focal length of the projection lens 164 according to the topographic data.

The yellow light source 169 is used to monitor whether the carrier plate 141 is parallel to the print head 142. The yellow light source 169 reflects the light to the projection lens 164 through the mirror 163, and the CCD monitoring system 165 monitors the heights of the four corners of the loading plate 141, so that the surface of the printing head 142 and the upper surface of the pre-printed material are parallel to each other by the pre-printed layer of the material. The 3D printing system 10 of the present invention uses the DMD light modulator 162 to emit the projection pattern, and the brightness of the projection pattern in different areas in the same plane can be controlled, thereby satisfying the requirement of 3D printing in different shapes in the same cross section. The 3D printing system 10 is additionally provided with the film pressing mechanism 143, the driving roller 122 is arranged in front, so that the printing conveyor belt 123 is kept flat, the film pressing mechanism 143 is used for pressing the printing conveyor belt 123 during 3D printing, the printing precision of the printing platform 14 is improved, meanwhile, the yellow light source 169 is added, whether the loading plate 141 and the printing head 142 are parallel or not is detected by the yellow light source 169, and the surface of the printing head 142 and the surface of the preprinting layer are kept parallel by printing one preprinting layer, so that the printing precision is improved. The 3D printing system 10 provided by the invention has high printing precision, can realize the two-dimensional structure precision of 8um and the layer thickness precision of 5um, can well meet the specific requirements of a biological device on the forming size (for example, the size of a microfluidic biological device is 1-4 inches), and provides a technical platform with innovative significance for the design of the biological device and the research in the field of biological medicines.

In addition, the 3D printing system 10 of the present invention can realize mixed printing of multiple materials by applying printing materials layer by layer, which is of great significance to biological applications, for example, in the case of 3D printing simulating human ears, mixed printing of cartilage-like material, muscle-like material and muscle fiber is required, mixed printing can be realized by supplying cartilage-like material using the first supply tank 124a, supplying muscle-like material using the second supply tank 124b, supplying muscle fiber using the third supply tank 124c, and controlling the timing of the supply of the first supply tank 124a, the second supply tank 124b and the third supply tank 124c during 3D printing.

Fig. 2 is a schematic flow chart of a 3D printing method according to the present invention. Referring to fig. 1 and 2, the 3D printing method of the present invention utilizes a 3D printing system 10 to perform 3D printing, and the steps of the 3D printing method include:

providing a feeding mechanism 12, wherein the feeding mechanism 12 comprises a printing conveyor belt 123, a supply tank 124 and a scraper 125, the supply tank 124 discharges printing materials onto the printing conveyor belt 123, and the scraper 125 scrapes the printing materials evenly;

specifically, the supply tanks 124 include a first supply tank 124a, a second supply tank 124b, a third supply tank 124c, a first doctor 125a, a second doctor 125b, and a third doctor 125c, the first supply tank 124a is used to discharge the printing material onto the printing conveyer 123, the first doctor 125a is used to smooth the printing material, or the first supply tank 124a, the second supply tank 124b, and the third supply tank 124c are controlled in sequence to discharge the printing material onto the printing conveyer 123, and the first doctor 125a, the second doctor 125b, and the third doctor 125c are controlled in sequence to smooth the printing material, wherein the printing materials discharged from the first supply tank 124a, the second supply tank 124b, and the third supply tank 124c are different from each other.

Providing a printing platform 14, wherein the printing platform 14 comprises a loading plate 141, a printing head 142 and a film pressing mechanism 143, the printing material discharged onto the printing conveyor belt 123 is conveyed onto the loading plate 141, and the film pressing mechanism 143 is controlled to press downwards; and

an imaging mechanism 16 is provided, and a projection pattern is generated by the imaging mechanism 16, so that the projection pattern irradiates the printing material on the carrying plate 141, and the printing material is solidified into a printing entity on the printing platform 14.

Specifically, before 3D printing, since the loading plate 141 may be in a tilted state, the print head 142 may press the print conveyer 123. It is desirable to preprint a layer of material on the carrier plate 141 to ensure that the surface of the print head 142 is parallel to the top surface of the preprinted material. The heights of the four corners of the loading plate 141, i.e., the inclinations of the loading plate 141, are first monitored by the CCD monitoring system 165. The computer 176 then sets the layer thickness of the pre-printed material by tilting the carrier plate 141 to ensure that the surface of the print head 142 is parallel to the upper surface of the pre-printed material. Then, a normal 3D printing job is performed.

Specifically, the imaging mechanism 16 includes a light source 160a, a beam shaper 161, a DMD light modulator 162, a plurality of mirrors 163, a projection lens 164, a CCD monitoring system 165, a controller 166, a computer 167, a photodetector 168, a focusing light source 160b, and a yellow light source 169.

Shaping the light emitted from the light source 160a with a beam shaper 161;

the DMD light modulator 162 generates a planar projection pattern from the shaped light beam;

providing, with the computer 167, displacement data and a pattern file that segments the exposure data into a series of long strips, and sending the displacement data and the pattern file to the controller 166;

uploading a pattern file to the DMD light modulator 162 by using the controller 166, so that the DMD light modulator 162 displays a print pattern, and the shaped light passes through the DMD light modulator 162 to generate a corresponding projection pattern; meanwhile, the controller 166 controls the projection lens 164 to move along the length direction of the printing conveyer 123 according to the displacement data, so as to realize large-scale projection scanning exposure.

The CCD monitoring system 165 is used for monitoring the printing condition of the printing platform 14, the image is sent to the computer 167, the computer 167 is used for displaying the printing picture, and the printing condition is monitored in real time. The controller 166 controls the CCD monitoring system 165 and the projection lens 164 to move synchronously through displacement data;

the photo detector 168 is used to collect the light reflected from the surface of the printing material and send the generated profile data to the controller 166, and the controller 166 adjusts the projection focal length of the projection lens 164 according to the profile data.

The 3D printing system 10 provided by the present invention has a feeding mechanism 12 including a first feeding tank 124a, a second feeding tank 124b and a third feeding tank 124c, wherein the printing material provided by each feeding tank is discharged onto a printing conveyer 123 layer by layer, and is leveled by layer by scraping with each scraper, the printing conveyer 123 transports the printing material onto a loading plate 141 of the printing platform 14, and the printing conveyer 123 on both sides of the printing platform 14 is pressed by a film pressing mechanism 143, and the imaging mechanism 16 generates a projection pattern and projects the projection pattern onto the printing material of the printing platform 14 to solidify the printing material into a printing entity. Wherein, when 3D prints on printing conveyer belt 123, compress tightly printing conveyer belt 123 through press mold mechanism 143, keep printing conveyer belt 123's steady, help improving the printing precision. The 3D printing system 10 of the present invention realizes mixed printing of multiple materials by coating the printing materials layer by layer, and is of great significance to biological applications.

As used herein, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, including not only those elements listed, but also other elements not expressly listed.

In this document, the terms front, back, upper and lower are used to define the components in the drawings and the positions of the components relative to each other, and are used for clarity and convenience of the technical solution. It is to be understood that the use of the directional terms should not be taken to limit the scope of the claims.

The features of the embodiments and embodiments described herein above may be combined with each other without conflict.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A 3D printing system (10) comprising a feeding mechanism (12), a printing platform (14) and an imaging mechanism (16), characterized in that the feeding mechanism (12) comprises a pay-off reel (121), a drive roller (122) and a supply tank (124), a printing conveyer (123) is wound on the pay-off reel (121), the supply tank (124) can discharge a plurality of printing materials layer by layer onto the printing conveyer (123) and drive the printing materials to be conveyed onto the printing platform (14) by the drive roller (122);

the printing platform (14) comprises a carrying plate (141), a printing head (142) and a film pressing mechanism (143), wherein the carrying plate (141) is arranged below the printing conveyor belt (123) and is used for carrying and positioning printing materials; the printing head (142) is arranged above the printing conveyor belt (123) and is used for printing products; the film pressing mechanism (143) is arranged on two sides of the loading plate (141) and above the printing conveyor belt (123) and is used for fixedly pressing the printing conveyor belt (123);

the imaging mechanism (16) can generate a projection pattern for irradiating printing materials, and the projection pattern is irradiated on the printing materials on the carrying plate (141), so that the printing materials are solidified into a printing entity on the printing platform (14);

the imaging mechanism (16) comprises a plurality of reflectors (163), a yellow light source (169), a projection lens (164) and a CCD monitoring system (165), wherein light emitted by the yellow light source (169) is reflected to the projection lens (164) through the reflectors (163), and the CCD monitoring system (165) monitors the heights of four corners of the carrying plate (141) and sets the layer thickness of a pre-printed material so as to ensure that the surface of the printing head (142) is parallel to the upper surface of the pre-printed material.

2. The 3D printing system (10) of claim 1, wherein the supply tank (124) includes a first supply tank (124a), a second supply tank (124b), and a third supply tank (124c) arranged in sequence, the first supply tank (124a), the second supply tank (124b), and the third supply tank (124c) discharging the same printing material, or two of the same printing material, or all of the different printing material; the feed mechanism (12) further includes a scraper (125), the scraper (125) including a first scraper (125a), a second scraper (125b), and a third scraper (125c), the first scraper (125a) for leveling the printing material discharged from the first feed tank (124a), the second scraper (125b) for leveling the printing material discharged from the second feed tank (124b), and the third scraper (125c) for leveling the printing material discharged from the third feed tank (124 c).

3. The 3D printing system (10) as defined in claim 2 wherein the first doctor blade (125a) is positioned behind the first feed tank (124a), the second doctor blade (125b) is positioned behind the second feed tank (124b), and the third doctor blade (125c) is positioned behind the third feed tank (124c), the first doctor blade (125a), the second doctor blade (125b), and the third doctor blade (125c) having cutting edges positioned opposite the print belt (123).

4. The 3D printing system (10) according to claim 1, wherein the 3D printing system (10) further comprises a winding mechanism (18), the winding mechanism (18) is disposed behind the printing platform (14), the winding mechanism (18) comprises a residue curing lamp (181) and a winding disc (182), the residue curing lamp (181) is disposed above the printing conveyor (123) and can emit the uv light to cure the printing material remaining after printing, and the winding disc (182) is used for winding the printing conveyor (123).

5. The 3D printing system (10) as claimed in claim 4, wherein the two ends of the print belt (123) are respectively wound around the unwinding reel (121) and the winding reel (182), and after the driving roller (122) is disposed on the unwinding reel (121), the driving roller (122) drives the print belt (123) to move in a direction approaching the winding reel (182) through the supply tank, the printing platform (14) and the residue curing lamp (181).

6. The 3D printing system (10) of claim 1, wherein the imaging mechanism (16) comprises a light source (160a), a beam shaper (161), and a DMD light modulator (162), the beam shaper (161) for shaping the light beam emitted by the light source (160 a);

the DMD light modulator (162) is used for generating a planar projection pattern from the shaped light beam;

the reflector (163) is used for reflecting the projection pattern to the projection lens (164);

the projection lens (164) is arranged opposite to the printing platform (14), and the projection lens (164) can project a projection pattern on a printing material.

7. The 3D printing system (10) as claimed in claim 6, wherein the imaging mechanism (16) further comprises a computer (167) and a controller (166), the computer (167) is configured to provide displacement data and divide the exposure data into a series of striped pattern files, and send the displacement data and the pattern files to the controller (166), the controller (166) uploads the pattern files to the DMD light modulator (162) in time sequence to enable the DMD light modulator (162) to generate the projected pattern, and the controller (166) controls the projection lens (164) to move close to the print belt (123) according to the displacement data.

8. The 3D printing system (10) as claimed in claim 7, wherein the imaging mechanism (16) further comprises a photodetector (168), the CCD monitoring system (165) is configured to monitor the printing condition of the printing platform (14) and the topography and layer thickness of the current printing layer, and send the printing condition and the printing data of the topography and layer thickness of the current printing layer to the computer (167), the computer (167) can calculate the printing accuracy from the printing data, and the controller (166) controls the CCD monitoring system (165) and the projection lens (164) to move synchronously through displacement data;

the photoelectric detector (168) is used for collecting light reflected by the surface of the printing material and sending generated profile data to the controller (166), and the controller (166) adjusts the projection focal length of the projection lens (164) according to the profile data.

9. A3D printing method is characterized by comprising the following steps:

providing a feed mechanism (12), the feed mechanism (12) including a print belt (123), a supply tank (124), and a doctor blade (125), the supply tank (124) discharging printing material onto the print belt (123), the doctor blade (125) doctoring the printing material;

providing a printing platform (14), wherein the printing platform (14) comprises a loading plate (141), a printing head (142) and a film pressing mechanism (143), the printing material on the printing conveyor belt (123) is conveyed onto the loading plate (141), and the film pressing mechanism (143) is controlled to be pressed downwards to perform 3D printing;

providing an imaging mechanism (16) comprising a CCD monitoring system (165); firstly, the heights of four corners of the carrying plate (141) are monitored by using the CCD monitoring system (165), and the layer thickness of a pre-printed material is set so as to ensure that the surface of the printing head (142) is parallel to the upper surface of the pre-printed material;

then, generating a projection pattern by using the imaging mechanism (16), enabling the projection pattern to irradiate the printing material on the carrying plate (141), and enabling the printing material to be solidified into a printing entity on the printing platform (14);