CN112265262A

CN112265262A - Photocuring type 3D printing device

Info

Publication number: CN112265262A
Application number: CN201910610274.5A
Authority: CN
Inventors: 侯锋
Original assignee: Shanghai Prismlab Information Technology Co ltd; Prismlab China Ltd
Current assignee: Prismlab Information Technology Ltd; Shanghai Pulisheng 3d Technology Co ltd
Priority date: 2019-07-08
Filing date: 2019-07-08
Publication date: 2021-01-26
Anticipated expiration: 2039-07-08
Also published as: WO2021004064A1; CN112265262B

Abstract

This invention provides a photopolymerization 3D printing device, comprising: a housing containing liquid photosensitive resin for molding workpieces, wherein the interior of the housing is a low-pressure environment; a lifting platform disposed within the housing for supporting the workpieces; a drive mechanism for driving the lifting platform to perform lifting movements; and an optical system located below the housing for irradiating a beam pattern, thereby controllably curing a layer of photosensitive resin at the bottom of the housing.

Description

Photocuring type 3D printing device

Technical Field

The present disclosure relates to three-dimensional (3D) printing devices, and particularly to a light-curable 3D printing device.

Background

The 3D printing technology is characterized in that a computer three-dimensional design model is used as a blueprint, the model is layered through software, special materials such as metal powder, ceramic powder, plastics, cell tissues and the like are stacked layer by layer and bonded through modes such as laser beams, hot melting nozzles and the like, and finally, the materials are stacked and molded to manufacture a solid product. Different from the traditional manufacturing industry which produces final finished products by shaping, cutting and other modes of raw materials through machining modes such as a die, turning and milling, the 3D printing method changes a three-dimensional entity into a plurality of two-dimensional planes, and production is carried out through material treatment and layer-by-layer superposition, so that the manufacturing complexity is greatly reduced. The digital manufacturing mode can generate parts in any shape directly from computer graphic data without complex process, huge machine tool and much manpower, so that the production and the manufacturing can be extended to a wider production crowd.

At present, the forming mode of the 3D printing technology is still evolving, and the used materials are various. Among various molding methods, the photocuring method is a well-established method. The light curing method is to perform material accumulation molding by using the principle that a photosensitive material (usually photosensitive resin) is cured after being irradiated by ultraviolet laser, and has the characteristics of high molding precision, good surface smoothness, high material utilization rate and the like.

Fig. 1 is a schematic diagram of a basic structure of a photo-curing 3D printing apparatus. The 3D printing apparatus 100 includes a liquid tank 110 for containing photosensitive resin, an optical system 120 for curing the photosensitive resin, and a lifting platform 130 for attaching a molded workpiece. The optical system 120 is located below the liquid container 110 and can irradiate a light beam pattern to cure a layer of photosensitive resin on the bottom surface of the liquid container 110, and the cured photosensitive resin is adhered to the bottom surface of the lifting platform 130. After each time the optical system 120 irradiates the beam pattern to cure one layer of photosensitive resin, the lifting platform 130 slightly ascends to lift the cured layer of photosensitive resin and allows the photosensitive resin which is still in a liquid state to flow into the space between the bottom contact layer of the liquid containing tank 110 and the cured resin to wait for the next irradiation. And circulating the steps, printing layer by layer from the topmost layer to the bottommost layer of the three-dimensional model, and accumulating to obtain the formed three-dimensional workpiece.

During the lifting process of the lifting platform 130, there is no air gap between the cured resin and the contact layer on the bottom surface of the liquid containing tank 110, and the cured resin is pressed on the contact layer by the atmospheric pressure. Under the dual action of the resistance formed by the atmospheric pressure and the inherent adhesive force of the light-cured resin and the bottom surface of the liquid containing groove, the lifting platform 130 is difficult to lift the cured resin together when lifting, and the partially cured resin remains on the bottom surface of the liquid containing groove 110, which causes defects in the molded workpiece. The inherent adhesive force between the light-cured resin and the bottom surface of the liquid containing groove 110 can be relieved by adding the non-adhesive layer on the bottom surface of the liquid containing groove 110, but when the exposure area is larger, the atmospheric pressure can be the main reason for the difficulty in separating the contact layer on the bottom surface of the liquid containing groove 110 from the cured resin, particularly when the exposure area enters a micrometer-nanometer scale, the requirement on the contact layer is extremely high, hard materials such as glass and the like are required to be used as the contact layer, the pressure caused by the atmospheric pressure cannot be released through stripping, and the problem is more obvious.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a photocuring type 3D printing device to reduce the lifting pressure of a lifting platform and ensure the integrity of a formed workpiece.

In order to solve the above technical problem, the present invention provides a photo-curing type 3D printing apparatus, including: the device comprises a shell, a liquid photosensitive resin used for forming a workpiece is contained in the shell, wherein the interior of the shell is in a low-pressure environment; the lifting platform is arranged in the shell and used for bearing a formed workpiece; the driving mechanism drives the lifting platform to do lifting motion; and the optical system is positioned below the shell and can irradiate a light beam pattern to ensure that a layer of photosensitive resin at the bottom in the shell is cured controllably.

In an embodiment of the present invention, the bottom of the housing has a contact layer, and the contact layer is a non-stick material.

In an embodiment of the present invention, the driving mechanism is a stepping or servo motor, and the stepping or servo motor is connected to the lifting platform through a lead screw.

In an embodiment of the present invention, the driving mechanism is located above the liquid photosensitive resin inside the housing, and the housing is provided with a vacuum hole, the vacuum hole is connected to a vacuum pump, and the vacuum pump is used for pumping low pressure or vacuum below atmospheric pressure inside the housing.

In an embodiment of the invention, the vacuum hole is further connected to a vacuum gauge for measuring the vacuum level inside the housing.

In one embodiment of the invention, the printer further comprises an exhaust hole, and after the printing task is completed, the exhaust hole is opened to release the low-pressure environment inside the shell.

In an embodiment of the present invention, the housing includes an openable panel or cover plate, and the panel or cover plate is connected to the housing main body by a sealing rubber ring in a sealing manner.

In one embodiment of the invention, the drive mechanism is located outside the housing, the housing is filled with liquid photosensitive resin, and the housing is further connected to a piston, the piston being in contact with the liquid photosensitive resin.

In one embodiment of the present invention, the piston is connected to a driver, and the driver drives the piston to reciprocate.

In an embodiment of the present invention, the apparatus further includes a storage tank, in which the liquid photosensitive resin is stored, and the stored liquid photosensitive resin can be injected into the housing.

Compared with the prior art, the invention has the following advantages: the invention keeps the interior of the shell for containing the liquid photosensitive resin in a low-pressure environment, reduces the atmospheric pressure applied to a printed piece, and enables the lifting platform to drive the formed workpiece to easily leave the bottom surface of the liquid containing groove, thereby protecting the success rate and integrity of the formed workpiece and improving the quality of the formed workpiece.

Drawings

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

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

fig. 2 is a front view of a schematic structural diagram of a photocuring-type 3D printing apparatus according to an embodiment of the present invention;

fig. 3 is a perspective view of a schematic configuration of the photocuring-type 3D printing apparatus shown in fig. 2;

fig. 4 is a bottom view of the structural schematic diagram of the photocuring-type 3D printing apparatus shown in fig. 2;

fig. 5 is a top view of a schematic perspective structure of the photo-curing type 3D printing apparatus shown in fig. 2;

FIG. 6 is a flow diagram of an exemplary process for printing by a 3D printing device according to one embodiment of the invention;

FIG. 7 is a flowchart of an exemplary process included in step 630 of FIG. 6;

fig. 8 is a perspective view of a schematic configuration of a photocuring-type 3D printing apparatus according to another embodiment of the present invention;

fig. 9 is a flowchart of an exemplary process of printing by the 3D printing apparatus according to an embodiment of the present invention.

Detailed Description

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

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

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

Flow charts are used in the present invention to illustrate operations performed according to embodiments of the present invention. It should be understood that the preceding or following operations are not necessarily performed in the exact order in which they are performed. Rather, various steps may be processed in reverse order or simultaneously. Meanwhile, other operations are added to or removed from these processes.

The photo-curing type 3D printing device comprises a shell, a lifting platform, a driving mechanism and an optical system. Liquid photosensitive resin for forming a workpiece is contained in the shell, and the interior of the shell is in a low-pressure environment; the lifting platform is arranged in the shell and used for bearing a formed workpiece; the driving mechanism can drive the lifting platform to do lifting motion; the optical system is positioned below the shell and can irradiate a light beam pattern, so that a layer of photosensitive resin at the bottom in the shell is cured controllably.

In the photo-curing 3D printing apparatus according to the embodiment of the invention, the bottom surface of the casing is usually made of a light-transmitting material, such as glass. The bottom surface of the housing may be entirely or partially composed of a light-transmissive material. An optical system located below the housing irradiates a beam pattern toward the bottom surface of the housing, the beam passing through the light-transmitting material to irradiate a photosensitive resin located on the bottom surface inside the housing, the photosensitive resin being cured in accordance with the irradiated beam pattern. The curing thickness (layer thickness) of the liquid photosensitive resin is determined by the distance between the molded workpiece and the contact layer on the bottom surface of the liquid tank 110.

In some embodiments, a contact layer is disposed on the lower surface of the interior of the housing in contact with the liquid photosensitive resin, and the contact layer is a release film made of a non-stick material. The contact layer can prevent the cured resin from being adhered to the lower surface of the inner part of the shell, and the cured resin can be conveniently peeled off from the lower surface of the inner part of the shell under the action of external force. In other embodiments, such as high precision micro-nano printing, non-stick layers are often applied directly to the glass due to the high precision requirements. Because the interior of the shell is in a low-pressure environment, after printing of a part or all of the three-dimensional models is completed, the driving mechanism in the 3D printing device cannot be subjected to pressure from the atmospheric pressure acting on a printing workpiece in the process of driving the lifting platform to do lifting motion. Therefore, the lifting platform can conveniently drive the solidified resin to ascend or descend, and the integrity of the formed workpiece is prevented from being damaged.

Fig. 2 is a front view of a schematic structural diagram of a light-curing type 3D printing apparatus according to an embodiment of the present invention. Referring to fig. 2, in this embodiment, the housing 210 of the photo-curing type 3D printing apparatus is a closed box. The optical system 220 is located below the housing 210 and at a distance from the housing 210. It is understood that the shape of the housing 210 may be regular or irregular cube, rectangular parallelepiped, etc., and the schematic diagram of fig. 2 is not intended to limit the shape of the housing 210 in the photocurable 3D printing apparatus of the present invention. The housing 210 may be made of a light-transmitting material or a light-impermeable material except for a portion of the bottom thereof for transmitting light. The use of a transparent material is beneficial in facilitating the observation of the operation of the interior of the housing 210. The use of the opaque material is advantageous in that it can prevent stray light from entering the housing 210. Preferably, the housing 210 is formed by combining a transparent material and an opaque material.

From the front view shown in fig. 2, a front panel 211 with a handle is provided on the front surface of the housing 210, and the front panel 211 can be opened and closed. A cover 212 is provided on the top of the housing 210 to be opened and closed. In some embodiments, the face plate 211 and the cover plate 212 are both sealingly connected by a sealing grommet. In some embodiments, the cover plate of the housing 210 may be fixed on the housing 210. Regardless of the manner in which the panel 211 and the cover 212 are disposed on the housing 210, the tightness of the interior of the housing 210 is ensured when the panel 211 and/or the cover 212 are closed.

Referring to fig. 2, in this embodiment, a vacuum hole 213 is formed on the housing 210 on one side of the panel 211. In other embodiments, the vacuum holes 213 may be located elsewhere on the housing 210. The vacuum hole 213 is connected to a vacuum pump (not shown) for pumping the interior of the housing 210 to a low pressure state lower than the atmospheric pressure, thereby forming a low pressure environment in the housing 210. Ideally, the vacuum pump can evacuate the interior of the housing 210.

In some embodiments, the vacuum port 213 is further coupled to a vacuum gauge (not shown) for measuring the vacuum level inside the housing 210 and for indicating and controlling the operation of the vacuum pump.

Referring to fig. 2, in this embodiment, a vent hole 214 is formed in the case 210 on one side of the panel 211. In other embodiments, the vent 214 may be located elsewhere on the housing 210. After printing of the three-dimensional model is completed within the housing 210, the vent 214 may be opened to relieve the low pressure environment inside the housing 210.

Fig. 3 is a perspective view of a schematic configuration of the photocuring-type 3D printing apparatus shown in fig. 2. Referring to fig. 3, the housing 210 of the present embodiment includes a liquid tank 215 for containing liquid photosensitive resin, a lifting platform 230, and a driving mechanism 240. The driving mechanism 240 is connected to the lifting platform 230 through a lead screw 241, and the lifting platform 230 is driven by the lead screw 241 to reciprocate along the vertical direction.

Fig. 4 is a bottom view of the configuration diagram of the photocuring-type 3D printing apparatus shown in fig. 2. Referring to fig. 4, the bottom of the outer portion of the housing 210 of the present embodiment has a light-transmitting portion 217. The light emitted from the optical system 220 may pass through the light-transmitting portion 217, so that a layer of liquid photosensitive resin located inside the housing 210 is cured according to a light pattern. It should be understood that the illustration in fig. 4 is only for illustration and is not intended to limit the shape and size of the light-transmitting portion 217. In a preferred embodiment, the light-transmitting portion 217 is rectangular, and the bottom of the housing 210 is made of a light-impermeable material surrounding the light-transmitting portion 217, so as to prevent stray light from entering the bottom of the housing 210.

Fig. 5 is a plan view schematically illustrating a structure of the photocuring 3D printing apparatus shown in fig. 2. Referring to fig. 5, in this embodiment, the bottom of the housing 210 has a liquid tank 215 for containing liquid photosensitive resin. Above the liquid tank 215 there is a scraper 250. The driving mechanism 240 is located inside the housing 210 and above the liquid photosensitive resin, that is, the driving mechanism 240 is located above the liquid tank 215 and the squeegee 250. The lift platform 230 is also located inside the housing 210 and is coupled to a drive mechanism 240.

Referring to fig. 2-5, in this embodiment, the housing 210 is a rectangular parallelepiped structure. Since the driving mechanism 240 is disposed at the back plate of the housing 210 opposite to the front plate 211 and is located at a higher position, a portion of the cover plate 212 of the housing 210 close to the front plate 211 is a lower flat plate, and a portion close to the back plate is a higher flat plate, and the whole cover plate 212 is stepped in a front-low and back-high manner. The shape of the cover plate 212 of the 3D printing apparatus of the present invention is not limited as shown in fig. 2 to 5.

Fig. 6 is a flowchart of an exemplary process of printing by the 3D printing apparatus according to an embodiment of the present invention. The 3D printing apparatus of the embodiments shown in fig. 2 to 5 can perform printing of the three-dimensional model according to the flow steps shown in fig. 6. Referring to fig. 6, the printing process includes the steps of:

and step 610, injecting liquid photosensitive resin required by printing into a liquid containing groove in the shell, and closing a panel and/or a cover plate of the shell.

In this step, a liquid photosensitive resin sufficient for printing a desired three-dimensional model is injected into the liquid tank 215 in the housing 210, and the panel 211 and/or the cover 212 of the housing 210 are closed, so that the inside of the housing 210 is sealed.

And step 620, vacuumizing the interior of the shell through the vacuum hole in the shell by using a vacuum pump.

In this step, the air pressure inside the housing 210 is detected by the vacuum gauge connected to the vacuum hole 213, so as to ensure that the air pressure inside the housing 210 is low during the three-dimensional printing process, and preferably, the air pressure should be between 0 and 0.5 atmosphere.

Step 630, begin printing the three-dimensional model layer by layer.

Fig. 7 is a flowchart of an exemplary process included in step 630 of fig. 6. Referring to fig. 7, step 630 may include the following steps:

at the beginning of printing, the driving mechanism 240 drives the lifting platform 230 to make the distance between the lifting platform 230 and the bottom surface of the liquid containing tank 215 equal to the thickness of one layer of the three-dimensional model, step 631.

In step 632, the optical system 220 irradiates a light beam under the housing 210 according to the slice image of the topmost layer of the three-dimensional model to be printed, and the first layer of photosensitive resin is cured to form a first layer of printing surface.

In step 633, in some embodiments, after the one-layer printed surface is formed, the driving mechanism 240 drives the lifting platform 230 to lift upwards, and the lifting platform 230 drives the cured resin to lift for a certain distance and stop. The squeegee 250 in the 3D printing apparatus starts to operate, moving from one end of the liquid tank 215 to the other end, cleaning the contact layer for printing of the next layer of print surface. After the squeegee 250 is operated, the driving mechanism 240 drives the elevating platform 230 to descend to a position where the distance between the cured resin on the elevating platform 230 and the bottom surface of the liquid containing tank 215 is equal to the thickness of one layer of the printing surface. So that the next layer of cured resin can be joined to the previous layer of cured resin at the next photoprinting. Due to the use of the squeegee 250, the contact layer can be kept clean, and the quality of the formed workpiece can be improved.

In other embodiments, the scraper 250 may not be needed if the contact layer is clean, and after a layer of print surface is formed, the driving mechanism 240 may drive the lifting platform 230 to move up a distance greater than the thickness of the print surface layer and then down a distance from the liquid level equal to the thickness of a layer of three-dimensional model print surface.

In step 634, the optical system 220 irradiates a light beam toward the lower side of the housing 210 according to the pattern of the next slice image in the three-dimensional model, so that a layer of photosensitive resin on the bottom of the housing 210 is cured.

And repeating the steps 631 to 634, and printing the three-dimensional model to be printed layer by layer until the formed workpiece is finally obtained.

With continued reference to FIG. 6, at step 640, after printing of the entire three-dimensional model is completed, the vent holes in the housing are opened.

This step may allow air to enter the sealed enclosure 210, thereby relieving the low-pressure environment inside the enclosure 210. And the subsequent formed workpiece is convenient to take out.

In some embodiments, the drive mechanism 240 may be a stepper motor or a servo motor that is connected to the lift platform 230 through a lead screw 241. The lifting platform 230 can slide up and down along the lead screw 241 under the driving of a stepping motor or a servo motor.

The embodiment of the invention provides a light-curing type 3D printing device, which enables the interior of a shell for containing liquid photosensitive resin to be kept in a low-pressure environment, eliminates the large atmospheric pressure on the liquid photosensitive resin and a lifting platform, and enables the lifting platform to drive a formed workpiece to easily leave the bottom surface of a liquid containing groove, thereby protecting the integrity of the formed workpiece and improving the quality of the formed workpiece.

Fig. 8 is a perspective view schematically illustrating a structure of a light curing type 3D printing apparatus according to another embodiment of the present invention. This has the advantage that after the lift platform 230 is separated from the bottom surface of the interior of the housing 210, the liquid resin can be forced into the gap between the lift platform 230 and the bottom surface of the interior of the housing 210. Referring to fig. 8, in this embodiment, the housing 210 of the 3D printing apparatus is a closed container, the inside of the housing 210 is filled with liquid photosensitive resin, and the inside of the housing 210 is still in a low-pressure environment. The housing 210 is connected to a plunger 260. As shown in fig. 8, a boss 216 is provided near the bottom of the housing 210, the boss 216 is integral with the housing 210, and the plunger 260 is located in the boss 216. The plug portion 261 of the plunger 260 contacts the liquid photosensitive resin in the housing 210. The plug portion 261 is matched with the convex portion 216 of the housing 210 so that the liquid photosensitive resin in the housing 210 does not flow from one side of the plug portion 261 to the other side. The plunger 262 may be connected to a driver (not shown) that drives the plunger 262 to move the plunger 261 together in a reciprocating motion within the boss 216.

The schematic shown in fig. 8 does not limit the position of the protruding portion 216. In a preferred embodiment, the boss 216 is located near the bottom of the housing 210, as shown in FIG. 8. When the driver drives the piston 260 to move in the direction away from the shell 210, the negative pressure in the shell 210 is increased, so that the workpiece and the contact layer are conveniently separated; when the driver drives the plunger 260 to move towards the housing 210, the positive pressure in the housing 210 is increased, so that the liquid photosensitive resin flows into the gap between the workpiece and the contact layer formed after the lifting platform 230 is lifted, and the printing is accelerated.

Referring to fig. 8, in this embodiment, the 3D printing apparatus further includes a driving mechanism 240 located outside the housing 210. The driving mechanism 240 is connected to the elevating platform 230 inside the housing 210 through a lead screw 241. Also included outside the housing 210 is a reservoir tank 270, and the reservoir tank 270 stores liquid photosensitive resin therein. Storage case 270 is linked together with casing 210, when needs print, can pour into casing 210 with the liquid photosensitive resin that wherein store into, takes out storage case 270 with remaining liquid photosensitive resin again after printing finishes, conveniently takes out the printing. Of course, the connection between the driving mechanism 240 and the storage box 270 and the housing 210 should be airtight, so that the housing 210 can maintain a low-pressure environment during the printing process of the 3D printing apparatus.

In some embodiments, both the drive mechanism 240 and the driver may be stepper motors or servo motors.

Referring to fig. 8, in this embodiment, the 3D printing apparatus further includes a liquid containing tank 215. Since the liquid photosensitive resin fills the inside of the housing 210, the liquid tank 215 corresponds to the entire space inside the housing 210.

In this embodiment, the housing 210 has a rectangular parallelepiped structure from the perspective shown in fig. 8. The bottom surface of the housing 210, i.e., the surface to be illuminated by the optical system 220, needs to be completely or partially made of a transparent material, such as glass. A contact layer is provided on the lower surface of the inside of the case 210, which is in contact with the liquid photosensitive resin. The remainder of the housing 210 may be constructed of a transparent material or an opaque material. The use of a transparent material is beneficial in facilitating the observation of the operation of the interior of the housing 210. The use of the opaque material is advantageous in that it can prevent stray light from entering the housing 210. Preferably, the housing 210 is formed by combining a transparent material and an opaque material.

The illustration in fig. 8 is not intended to limit the shape and size of the housing 210. In other embodiments, the housing 210 may have other shapes to achieve the objectives of the present invention.

Fig. 9 is a flowchart of an exemplary process of printing by the 3D printing apparatus according to an embodiment of the present invention. The 3D printing apparatus of the embodiment shown in fig. 8 can perform printing of the three-dimensional model according to the flow steps shown in fig. 9. Referring to fig. 9, the printing process includes the steps of:

at step 910, the housing 210 is filled with a liquid photosensitive resin.

Referring to FIG. 8, the storage tank 270 and the housing 210 are connected by a pipe located at the lower portion of the storage tank 270 and the housing 210. A bi-directional feed pump and valve assembly 271 is provided in the line between the accumulator tank 270 and the housing 210. A purge valve 272 is provided at the top end of the housing 210.

In this step 910, the air release valve 272 may be opened first, and then the bidirectional transfer pump and the valve assembly 271 may be opened; then, the liquid photosensitive resin in the storage tank 270 is injected into the shell 210, or the liquid in the storage tank 270 can be pressed into the shell 210 by injecting air pressure into the top of the storage tank 270; after the casing 210 is completely filled with the liquid photosensitive resin, the air release valve 272 is closed; finally the bi-directional delivery pump and valve assembly 271 is closed.

At step 920, printing is started. At the beginning of printing, the driving mechanism 240 drives the lifting platform 230 to make the distance between the lifting platform 230 and the bottom surface of the liquid containing groove 215 equal to the thickness of one layer of the three-dimensional model. The driver drives the plug portion 261 of the piston 260 to move towards the housing 210, so as to generate positive pressure in the housing 210, thereby ensuring that the gap between the lifting platform 230 and the bottom surface of the liquid containing groove 215 is filled with resin material.

In step 930, the optical system 220 irradiates a light beam below the housing 210 according to the top slice image of the three-dimensional model to be printed, and the first layer of photosensitive resin is cured to form a first layer of printing surface.

In step 940, the driver drives the plug portion 261 of the plunger 260 to move in a direction away from the housing 210, so as to generate a negative pressure in the housing 210. In this step, the pressure inside the housing 210 may be measured by a pressure sensor (not shown), and when the pressure value reaches a set requirement (for example, 0 to 0.5 atm), the movement of the plug 261 is stopped. The present invention does not limit the location of the pressure sensor.

In step 950, the driving mechanism 240 drives the lifting platform 230 to ascend to a suitable position, so that the distance between the cured resin on the lifting platform 230 and the bottom surface of the liquid tank 215 is suitable for the inflow of the liquid photosensitive resin.

In step 960, the driver moves the plug portion 261 of the plunger 260 in a direction approaching the housing 210, thereby generating a positive pressure in the housing 210. In this step, the pressure inside the housing 210 may be measured by a pressure sensor (not shown), and when the pressure value reaches a set requirement (e.g., 1-2 atmospheres), the plug 261 stops moving.

In step 970, the driving mechanism 240 drives the lifting platform 230 to descend, so that the distance between the cured resin on the lifting platform 230 and the bottom surface of the liquid containing groove 215 is equal to the thickness of one layer of printing surface.

In step 980, the optical system 220 irradiates a light beam to the lower side of the housing 210 according to the pattern of the next slice image in the three-dimensional model, so that a layer of photosensitive resin on the bottom of the housing 210 is cured. And also allows the next layer of cured resin to bond with the previous layer of cured resin. And repeating the steps 940-980, and printing the three-dimensional model to be printed layer by layer until the molded workpiece is finally obtained.

At step 990, after the printing is completed, the air release valve 272 and the bidirectional transfer pump and valve assembly 271 are opened, the photosensitive resin material in the housing 210 is transferred back to the storage tank 270, and the bidirectional transfer pump and valve assembly 271 is closed after all the photosensitive resin material is transferred back to the storage tank 270.

It should be noted that, because the photosensitive resin material shrinks to some extent when it is cured, the equilibrium position of the plug 261 in the protruding portion 216 will gradually move toward the housing 210, and therefore, it is necessary to ensure that the protruding portion 216 has a sufficient length to make the pressure in the housing 210 reach the set positive and negative air pressure.

The embodiment of the invention provides a photocuring type 3D printing device, which enables the interior of a shell for containing liquid photosensitive resin to be kept in a low-pressure environment, eliminates the atmospheric pressure on the liquid photosensitive resin and a lifting platform as required, and enables the lifting platform to drive a formed workpiece to easily leave the bottom surface of a liquid containing groove, thereby protecting the integrity of the formed workpiece and improving the quality of the formed workpiece.

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

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

Claims

1. A light-curing 3D printing device, comprising:

a casing, wherein the liquid photosensitive resin for forming the workpiece is contained in the casing, wherein the inside of the casing is a low-pressure environment;

Lifting platform, set in the shell, used to carry the forming workpiece;

a driving mechanism, which drives the lifting platform to perform lifting motion;

The optical system, located under the casing, can irradiate a light beam pattern, so that a layer of photosensitive resin at the inner bottom of the casing can be controllably cured.

2 . The light-curing 3D printing device according to claim 1 , wherein the bottom of the casing has a contact layer, and the contact layer is a non-stick material. 3 .

3 . The light-curing 3D printing device according to claim 1 , wherein the driving mechanism is a stepping or servo motor, and the stepping or servo motor is connected to the lifting platform through a lead screw. 4 .

4 . The photocurable 3D printing device according to claim 1 , wherein the driving mechanism is located above the liquid photosensitive resin inside the casing, the casing is provided with a vacuum hole, and the vacuum hole Connected to a vacuum pump for evacuating a sub-atmospheric pressure or vacuum inside the housing.

5 . The light-curing 3D printing device according to claim 4 , wherein the vacuum hole is further connected to a vacuum gauge, and the vacuum gauge is used to measure the vacuum degree inside the casing. 6 .

6 . The light-curing 3D printing device according to claim 3 , further comprising an exhaust hole, and after the printing task is completed, the exhaust hole is opened to relieve the low-pressure environment inside the casing. 7 .

7 . The light-curing 3D printing device according to claim 2 , wherein the housing comprises an openable panel or cover, and the panel or cover is sealed with the housing body by a sealing rubber ring. 8 . connect.

8 . The light-curing 3D printing device according to claim 1 , wherein the driving mechanism is located outside the casing, the casing is filled with liquid photosensitive resin, and the casing is further connected to a piston. 9 . , the piston is in contact with the liquid photosensitive resin.

9 . The light-curing 3D printing device of claim 8 , wherein the piston is connected to a driver, and the driver drives the piston to reciprocate. 10 .

10 . The light-curing 3D printing device according to claim 6 , further comprising a storage box, wherein the storage box stores liquid photosensitive resin, and the stored liquid photosensitive resin can be injected into the shell. 11 . in the body.