CN113635553B

CN113635553B - 3D printing system and method

Info

Publication number: CN113635553B
Application number: CN202110826906.9A
Authority: CN
Inventors: 夏春光; 贺晓宁
Original assignee: Bmf Nano Material Technology Co ltd
Current assignee: Bmf Nano Material Technology Co ltd
Priority date: 2021-07-21
Filing date: 2021-07-21
Publication date: 2023-05-23
Anticipated expiration: 2041-07-21
Also published as: CN113635553A

Abstract

The application relates to a 3D printing system, comprising: a film for attaching the printed sample to cure under irradiation of the optical engine; a membrane separator movable along an upper surface of the membrane, the membrane separator comprising: a housing having a second cavity on a side thereof facing the membrane; a first roller rotatably installed at one side of the second cavity; a second roller rotatably installed at the other side of the second cavity; and the vacuum source is connected with the shell and used for generating negative pressure in the second cavity. The beneficial effects of the invention are as follows: the membrane separator can effectively separate the membrane from the printing sample, the membrane is not damaged in the process, the separation effect is good, and errors caused by the arrangement of the oxygen inhibition layer in the traditional method are avoided.

Description

3D printing system and method

Technical Field

The invention relates to a 3D printing technology, in particular to a 3D printing system and a 3D printing method which are convenient for separating films.

Background

Stereolithography was originally considered a rapid prototyping technique and refers to a series of techniques that were used to create true scale models of production parts directly from Computer Aided Design (CAD) in a rapid (faster than before) manner. Since its concept was developed and passed through the disclosure in us patent 4575330, stereolithography not only has a great help to engineers, but it also allows, among many other functions, visualization of complex three-dimensional part geometries, detection of errors in prototype schematics, testing of critical components, and verification of theoretical designs with lower cost and shorter time frames.

Over the last few decades, the advent of micro-stereolithography ([ mu ] SL), which inherits the basic principles of traditional stereolithography but has a very high spatial resolution, has been facilitated by continued improvements in the field of microelectromechanical systems (MEMS). In 1993, at the 6 th institute of IEEE microelectromechanical systems, K Ikuta and K. Hirowataris, expressed above in "true three-dimensional micromachining using stereolithography and metal forming". With the aid of single photon polymerization and two photon polymerization techniques, the resolution of μsl is further increased to less than 200 nm. S. Maruo and K. Ikuta in appl. Phys. Lett, vol.76, 2000 "three-dimensional microfabrication Using Single photon Crystal", J. MEMS in vol.7, pp., 411 "near infrared photopolymerization for two photon absorption for two-dimensional microfabrication", and S. Kawata, H.B. Sun, T. Tanaka, and K. Takada are published in Nature, vol.412, pp. 697, 2001, "Finer Features for Functional Microdevices", all express the above.

Bertsch et al, microsystem Technologies, pp. -47, 1997, "Microstereophotolithography using a Liquid Crystal Display as Dynamic Mask-Generator," herein and Beluze et al, proceedings of SPIE, v3680, n2, pp. 808-817, 1999, "Microstereinithographic: A New Process to Build Complex D objects, symposi μm on Design, test and Microfabrication of MEMs/MOEMs," herein all indicate that the speed of the micro-stereolithography technique [ mu ] SL is greatly increased as the projection micro-stereolithography technique (P [ mu ] SL) is developed. At the heart of this technology is a high resolution spatial light modulator, which may be a Liquid Crystal Display (LCD) panel or a Digital Light Processing (DLP) panel, both of which are available from the microdisplay industry.

While projection microlithography (psl) technology has been successful in providing fast manufacturing speeds with good resolution, further improvements are still needed. There are three types of resin layer definition methods in projection microlithography (pμl): the first uses a free surface, where the layer thickness is defined by the distance between the resin free surface and the sample stage. Due to the slow viscous movement of the resin, when the print area is larger than 1cm x 1cm, it takes more than half an hour to determine a 10 μm thick resin layer having a viscosity of 50 cPs. The second and third methods use transparent films or hard windows. The materials of the film and the rigid window in some printing methods are breathable, typically oxygen permeable, such as PDMS or Teflon AF, such that the breathable material forms a so-called "dead zone" in the photopolymerization-inhibiting layer or CLIPS technology. Due to the oxygen inhibited layer, the film does not stick to the printed sample. However, the thickness of the constraining layer is 20 to 50 microns, which can be a large source of dimensional errors in precision 3D printing, as the tolerance requirements in printing can be at the same or even smaller levels. On the other hand, since the oxygen barrier layer is thicker, the flow resistance due to the higher viscosity of the resin significantly reduces the printing speed, especially for dense parts without internal channel connections. It can be seen that in precision 3D printing, an oxygen inhibition layer is provided so that the separation film brings about a certain error.

Disclosure of Invention

The invention aims to solve the technical problems that: in order to solve the problem that a certain error is brought to the separation membrane by arranging the oxygen inhibition layer in the prior art, the 3D printing system and the method for facilitating the separation membrane are provided.

The technical scheme adopted for solving the technical problems is as follows:

a 3D printing system, comprising:

a film for attaching the printed sample to cure under irradiation of the optical engine;

a membrane separator movable along an upper surface of the membrane, the membrane separator comprising:

a housing having a second cavity on a side thereof facing the membrane;

a first roller rotatably installed at one side of the second cavity;

a second roller rotatably installed at the other side of the second cavity;

the vacuum source is connected with the shell and used for generating negative pressure in the second cavity;

the membrane separator (120) further comprises a buffer chamber (124) arranged in the shell (122), one side of the buffer chamber (124) is connected with the vacuum source through a vacuum port connecting piece (130), and the other side is communicated with the second cavity (122 b);

the buffer chamber (124) comprises a third cavity (124 a), a plurality of orifices (124 b);

the inner surface of the housing defines a pair of curved portions (122 c) that match the outer contours of the first roller (126) and the second roller (128);

the buffer chamber (124) is disposed inside the housing (122) and defines a third cavity (124 a) therein, and a plurality of apertures (124 b) are formed through the housing (122) to communicate the third cavity (124 a) of the buffer chamber (124) to the second cavity (122 b) of the housing (122);

the first roller (126) is made of metal or ceramic with a 50-100 μm thick silicone or rubber surface coating, the metal or ceramic core material maintaining the first roller (126) rigid, maintaining a small gap of 50-100 μm between the first roller (126) and the inner surface (122 a) of the housing (122) when the first roller (126) is rolled on the film (110) under vacuum conditions;

a first space (122 e) between the first roller (126) and the second roller (128) causes a pressure drop between the top and bottom surfaces of the film (110) of 100-200Pa, causing the film (110) to deform by bouncing the film (110) up by 150-200 μm, thereby peeling the film (110) from the print sample (140);

the gap between the first roller (126) and the second roller (128) is between 1.5 and 2 times the roller diameter.

Preferably, the material of the first roller (126) and the second roller (128) is a metal material, a ceramic material or a combination of metal and ceramic material, and the surface of the first roller (126) and/or the second roller (128) is coated with a protective layer.

Preferably, the first roller (126) and the second roller (128) are both installed in the second cavity (122 b) through bearings (126 c), and the distance between the inner wall of the second cavity (122 b) and the outer walls of the first roller (126) and the second roller (128) is 50 [ mu ] m-100 [ mu ] m; the axial center distance between the first roller and the second roller is 12.5mm, which is 2.5-3 times of the diameter of the rollers; the width of the first space is 7.5mm and is 1.5-2 times of the diameter of the roller.

Preferably, the first roller and the second roller cooperate to form a gap of 7.5mm, 1.5-2 times the roller diameter, the buffer chamber restricting air flow between the buffer chamber (124) and the second cavity (122 b) of the housing (122) in an array of 10 x 500 μm apertures, the first roller and the second roller being two parallel rollers of 5mm diameter and 7.5mm apart.

Preferably, the third cavity (241 a) is adjacent to the second cavity (122 b) and is communicated with the plurality of holes (124 b), the plurality of holes (124 b) are arranged along the axial direction of the first roller (126), and the holes (124 b) are aligned with the middle of the second cavity (122 b).

Preferably, in the 3D printing system of the present invention, the materials of the first roller and the second roller are metal materials, ceramic materials or metal and ceramic combined materials, and the surfaces of the first roller and/or the second roller are coated with a protective layer.

Preferably, in the 3D printing system of the present invention, the first roller and the second roller are both installed in the second cavity through bearings, and the distance between the inner wall of the second cavity and the outer walls of the first roller and the second roller is 50 μm to 100 μm.

Preferably, the 3D printing system of the present invention further comprises a buffer chamber provided in the housing, one side of the buffer chamber is connected to the vacuum source through a vacuum port connection, and the other side is communicated with the second cavity.

Preferably, in the 3D printing system of the present invention, the buffer chamber includes a third cavity adjacent to the second cavity and communicating through a plurality of the orifices, the plurality of the orifices are aligned along an axial direction of the first roller, and the orifices are aligned in a middle of the second cavity.

Preferably, the 3D printing system of the present invention further comprises:

the resin tank is used for storing printing consumables;

an optical engine for projecting an image to cure the printing consumable;

the sample bearing table is arranged in the resin tank and is connected with a multi-shaft driving mechanism.

Preferably, the 3D printing system of the present invention further comprises: and the control computer is used for controlling the multi-shaft driving mechanism, the optical engine, the membrane separator and the membrane movement.

Preferably, in the 3D printing system of the present invention, a lens is disposed below the optical engine.

A 3D printing method, comprising the steps of:

printing a layer of resin on the lower surface of the film;

providing a membrane separator, the membrane separator comprising:

a housing having a second cavity on a side facing the membrane;

starting the vacuum source, then moving the membrane separator along the upper surface of the membrane, and gradually separating the membrane from the printed resin layer;

the membrane separator (120) further comprises a first roller (126) rotatably mounted on one side of the second cavity (122 b);

a second roller (128) rotatably installed at the other side of the second cavity (122 b);

Preferably, after one layer cures, the film separator (120) is left away from the printed sample (140) and a vacuum environment is created to hold the film (110) against the first roller (126) and the second roller (128),

thereafter, moving the sample stage (112) downward, i.e. away from the lens (104), 0.5mm to 2mm in direction, to create space for the resin (108 b) to flow under the membrane (110) behind the first roller (126) during membrane separation, the membrane separator (120) translating from one side of the membrane (110) to the other at a speed of 5 to 20mm/s while leaving a layer of fresh resin (108 b) between the membrane (110) and the print sample (140), the speed of the membrane separator being determined by the air flow speed between the membrane and the print sample, the speed being sufficiently slow to allow fresh resin to fill the gap after membrane separation;

next, the sample stage (112) is moved upward, i.e., in the direction of the lens (104), to define the thickness of the next layer, the membrane separator 120 is returned to the original position, the above process is repeated as the membrane 110 is flattened due to membrane tension or other coating technique, and the next layer image is projected onto the membrane (110), repeating the above steps until the complete printed sample 14 is replicated in the resin tank 108.

Preferably, in the 3D printing method of the present invention, the membrane separator further includes a first roller rotatably installed at one side of the second cavity;

and a second roller rotatably installed at the other side of the second cavity.

The beneficial effects of the invention are as follows:

the membrane separator can effectively separate the membrane from the printing sample, the membrane is not damaged in the process, the separation effect is good, and errors caused by the arrangement of the oxygen inhibition layer in the traditional method are avoided.

Drawings

The technical scheme of the application is further described below with reference to the accompanying drawings and examples.

FIG. 1 is a schematic diagram of a 3D printing system provided by the present invention;

FIG. 2 is a schematic diagram of the structure of a membrane separator of the 3D printing system of the present embodiment;

FIG. 3 is a schematic side view of the structure of the membrane separator of the present embodiment;

FIG. 4 is a schematic diagram of the principle of membrane separation of the present embodiment;

fig. 5 is a flowchart of the 3D printing method of the present embodiment;

fig. 6 is a process state diagram of a 3D printing system of the 3D printing method of the present embodiment.

The reference numerals in the figures are:

100. printing system

102. Optical engine

104. Lens

106. Control computer

108. Resin tank

108a first cavity

108b resin

110. Film and method for producing the same

112. Sample bearing table

112b second cavity

120. Membrane separator

122. Outer casing

122a inner surface

122b second cavity

122c curved surface portion

122e first space

124. Buffer chamber

124a third cavity

124b orifice

126. First roller

126c bearing

126d small gap

128. Second roller

130. Vacuum port connector

140. The sample was printed.

Description of the embodiments

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other.

In the description of the present application, it should be understood that the terms "center," "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of the present application. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application can be understood by those of ordinary skill in the art in a specific context.

The technical solutions of the present application will be described in detail below with reference to the accompanying drawings in combination with embodiments.

Examples

The present embodiments provide a more reliable 3D printing system and method that can separate films from printed samples at a faster rate during the P mu SL process. The method of the present embodiment is not limited to pμsl, but is also effective for any other printing system that uses a film to assist 3D printing. In one non-limiting embodiment, the method of the present embodiment uses a two-roll membrane separation in combination with the application of a transparent membrane and vacuum. The method not only can lightly separate the film from the printed sample in the P mu SL system, but also can insert a layer of printing material between the film and the printed sample. At the same time, due to the vacuum operation, ambient dust and dirt contaminating the film will be drawn away to protect the film from damage and maintain its optical clarity. The printing material in the present invention is typically a resin, such as a photocurable resin or a mixture thereof with solid particles, which is commonly used in industry for printing and curing build layers in 3D printing operations.

The roll membrane separator described in this embodiment has at least one roll, typically made of metal or ceramic, with a 50 μm to 100 μm thick silicone or rubber surface coating. In this embodiment, the membrane separator has two parallel rollers (first roller 126, second roller 128) of 5mm diameter and 7.5mm apart. In general, the smaller the diameter of the roll, the better. The gap between the first roller 126, the second roller 128 is typically between 1.5 and 2 times the roller diameter to create enough membrane deflection to separate the sample.

The 3D printing system of the present embodiment includes an optical engine, such as a DLP or LCD with a light source; a laser beam for projection microlithography or having a turning mirror for Stereolithography (SLA); a lens defining a magnification of a pixel size of the printing surface; a two-roll membrane separator on top of the membrane to separate the membrane from the printed sample; three precision platforms with the precision of 1 mu m are used for controlling the movement of the printing base material; to support a print substrate to print a sample or print an optical projection system in X, Y and Z directions; and a resin tank under the film. The system is arranged relative to a base plate of the substrate (e.g., a sample holder or sample) such that the lens is located between the surface of the sample carrier 112 and the optical engine 102.

Preferably in this embodiment, the membrane 110 is made of durable PFA (perfluoroalkoxyalkane) or FEP (fluorinated ethylene propylene). The thickness of the film is 50 μm or 100 μm, and is repeatedly deformed during the roll film separation scanning. Therefore, the resistance to deformation of the material is of paramount importance. Other materials, such as breathable Teflon AF (Teflon AF) from Dupont, whose photopolymerized oxygen inhibition can further reduce the separation force, can also be used.

Referring to fig. 1-4, a 3D printing system 100 is disclosed that includes an optical engine 102, a lens 104, a control computer 106, a resin tank 108, a membrane 110, a sample stage 112, and a membrane separator 120.

The optical engine 102 is in electrical communication with a control computer 106 and the lens 104. The control computer 106 includes a processor (not shown) and a memory (not shown) that may be coupled to the processor. The memory stores instructions that, when executed by the processor, may transmit an image to the optical engine 102 and then be emitted from the lens 104. As described above, the optical engine 102 may be a Digital Light Processing (DLP) projector, a Liquid Crystal Display (LCD) with a light source, or the like. In an embodiment, the optical engine 102 may include a laser, which may include a turning mirror or the like. It will be appreciated that the lens 104 determines the magnification of the pixel size on the printing surface.

The resin tank 108 may be any container capable of holding resin or other substances used in a stereolithography process. In this way, the resin tank 108 defines a first cavity 108a therein for retaining the resin 108b therein.

The film 110 may be an optically clear film and may be formed of durable Perfluoroalkoxyalkane (PFA) or Fluorinated Ethylene Propylene (FEP), although other suitable materials are also contemplated. The film 110 has a thickness of 50 μm to 100 μm and may be formed of an elastic material. In this way, the membrane 110 is subject to repeated deformation during use, and therefore deformation durability (over 10k cycles) is a critical property of the material. In an embodiment, the membrane 110 may be formed of a breathable teflon AF manufactured by dupont, which may further reduce the separation force from the cured resin due to oxygen inhibition by photopolymerization.

The sample stage 112 is a stage translatably supported within the first cavity 108a of the resin tank 108. In this way, the sample stage 112 translates in the Z direction toward and away from the lens 104 (e.g., in a vertical direction). The stage supports the 3D print sample 140 because the resin 108b in the resin tank 108 is polymerized and cured by the image emitted by the optical engine 102 and the lens 104. Specifically, after each layer of print sample 140 is formed, sample stage 112 is translated away from lens 104, causing a portion of fresh resin 108b to flow between the completed layer of print sample 140 and film 110. Sample stage 112 may be formed of any suitable material that can be used in a stereolithography process and may be of any suitable contour, such as circular, square, rectangular, etc.

The membrane separator 120 (fig. 2-4) includes a housing 122, a buffer chamber 124, a first roller 126, a second roller 128, and a vacuum port connection 130. The housing 122 is preferably generally rectangular in outline, but may also be oval, square, circular, etc. The housing 122 includes an inner surface 122a that defines a second cavity 122b of the interior of the housing 122. The inner surface 122a of the housing also defines a pair of curved portions 122c that match the outer contours of the first roller 126 and the second roller 128.

The buffer chamber 124 is disposed within the interior of the housing 122 and defines a generally open third cavity 124a therein. A plurality of apertures 124b extend through the housing 122 to communicate the third cavity 124a of the buffer chamber 124 with the second cavity 122b of the housing. In this way, the plurality of apertures 124b provide for an even distribution of vacuum along the length of the housing 122 when vacuum is applied thereto. In this embodiment, the buffer chamber 124 restricts air flow between the buffer chamber 124 and the second cavity 122b of the housing 122 in an array of 10×500 μm apertures 124 b. It will be appreciated that the plurality of orifices 124b increases the pressure drop across the housing 122, resulting in a more uniform air flow across the surfaces of the first roller 126 and the second roller 128 along the length of the membrane separator 120, and thus better pressure uniformity.

The first roller 126 and the second roller 128 are substantially similar, and therefore only the first roller 126 will be described in detail below. Preferably, the first roller 126 is made of metal or ceramic with a 50 μm-100 μm thick silicone or rubber surface coating (not shown), or any suitable material may be used, or the first roller may not be provided with a surface coating, or not at cost. In particular, the metal or ceramic is much harder than the film 110, so the first roller 126 may cause damage to the surface of the film 110 and thus reduce the optical transparency, e.g., the light transmittance of the film 110. Thus, the coating may protect the membrane 110 from scratches by the hard metal or ceramic of the first roller 126, while helping to seal the gas at the point of contact between the first roller 126 and the membrane 110. The protective layer of the first roller 126 may be a radially stretched tube or formed during a coating process such as dip coating or vapor deposition. The protective coating can significantly increase the coefficient of static friction between the first roller 126 and the film 110 by a factor of up to 10.

The first roller 126 is rotatably supported within the second cavity 122b of the housing by a pair of bearings 126c (fig. 2), the bearings 126c being disposed within a portion of the inner surface 122a of the housing. The pair of bearings 126c may be ball bearings, roller bearings, bushings, oil bearings, etc. In this embodiment, the bearing 126c is 5mm in diameter. A pair of bearings 126c ensures that the first roller 126 only rolls on the film 110 without slipping, and that the bearings 126c and roller surface coatings cooperate to avoid scratching the film 110.

The metal or ceramic core material allows the first roller 126 to remain rigid and maintains a small gap of 50 μm to 100 μm between the first roller 126 and the inner surface 122a of the housing 122 when the first roller 126 rolls on the film 110 under vacuum. In this manner, the first roller 126 is rotatably supported within the second cavity 112b of the housing 122, forming a small gap 126d (fig. 2 and 4) between the outer surface of the first roller 126 and the inner surface 122a of the housing 122. In the present embodiment, it is preferable that the small gap 126d minimizes the amount of air flowing between the outer surface of the first roller 126 and the inner surface 122a of the housing 122, provided that the first roller 126 is capable of freely rotating within the housing.

Specifically, the small gap 126d impedes air flow between the inner surface 122a of the housing and the outer surface of the first roller 126 and creates a pressure drop between the top and bottom surfaces of the membrane 110. The first roller 126 and the second roller 128 cooperate to form a gap of 7.5mm, typically 1.5 to 2 times the diameter of the rollers. As shown in fig. 4, the first space 122e between the first roller 126 and the second roller 128 causes a pressure drop between the top surface and the bottom surface of the film 110 of 100 to 200pa, and the film 110 is deformed by bouncing the film 110 up by 150 to 200 μm, thereby peeling the film 110 from the print sample 140. As the first roller 126 and the second roller 128 move over the film 110, the film 110 gradually separates from one side of the printed sample 140 to the other.

Parametrically, first roller 126 and second roller 128, 5mm in diameter, 12.5mm apart and 104mm long, may be used to cover a 100mm by 100mm print area. For a fixed membrane deflection, typically 200 microns, the spacing between the rollers will determine the pressure drop and thus the air flow rate during membrane separation. A larger pitch requires less flow to produce the same deflection. By considering the form factor of the film separation, in this embodiment, the axial distance of the first roller 126 and the second roller 128 is 12.5mm, typically 2.5 to 3 times the roller diameter; the width of the first space 122e is 7.5mm, typically 1.5 to 2 times the roller diameter.

Pressure is related to flow rate as shown by the bernoulli equation:

ρv ² +2P=Const

here ρ is the density, v is the flow rate, and P is the pressure. This equation shows that the pressure is lower at lower mach numbers along the flow streamlines in the higher velocity region. The bottom of the membrane 110 is subjected to a uniform atmospheric pressure, but the pressure at the top of the membrane 110 is dependent on the local flow rate of air. It is therefore important to have a uniform flow rate along the membrane separator 120, in an embodiment the membrane separator 120 is 104mm long. According to the present invention, the third cavity 124a of the membrane separator 120 is connected to a vacuum source (not shown) through a vacuum port connection 130 having a diameter of 5 mm.

Referring to fig. 1-6, there is provided a method of printing a 3D sample, comprising generating a 3D model in a control computer 106, and then slitting the generated 3D model into a sequence of images, wherein each image represents one layer (typically 5 μm-20 μm thick) of the generated 3D model (S100). The control computer 106 sends an image to the optical engine 102 and the image is projected through the lens 104 onto the bottom surface (which may be a wet surface) of the film 110 (as shown in step S102). The light areas of the projected image on the resin immediately below the film 110 are polymerized and cured, while the dark areas remain liquid (as shown in step S104). After one layer cures, the film separator 120 is left away from the print sample 140 and a vacuum environment is created to hold the film 110 against the first roller 126 and the second roller 128 (as shown in step S106). Thereafter, the sample stage 112 is moved downward (i.e., away from the lens 104) by 0.5mm to 2mm to create space for the resin 108b to flow under the film 110 behind the first roller 126 during the film separation process (as shown in step S108). The membrane separator 120 translates from one side of the membrane 110 to the other at a speed of 5 to 20mm/S while leaving a layer of fresh resin 108b between the membrane 110 and the print sample 140 (as shown in step S110), the speed of the membrane separator being determined by the air flow speed between the membrane and the print sample. The speed should be slow enough to allow fresh resin to fill the gap after membrane separation. Next, the sample stage 112 is moved upward (i.e., in the direction of the lens 104) to define the thickness of the next layer, and the membrane separator 120 is returned to the original position (as shown in step S112). When the film 110 is flattened due to film tension or other coating technique, such as the roll film coating technique of Boston Micro Fabrication, the above process is repeated and the next layer of image is projected on the film 110 (as shown in step S114). The above steps are repeated until the complete print sample 140 is replicated in the resin tank 108.

Although several embodiments of the present invention are illustrated in the accompanying drawings, the present invention is not intended to be limited thereto, as the scope of the invention is as broad as the art allows and reference should be made to the specification as well. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments.

In the drawings and the above description, terms such as front, rear, upper, lower, top, bottom, and the like are used for convenience of description only and are not intended to limit the present invention. In the previous descriptions, well-known functions or constructions are not described in detail to avoid obscuring the invention in unnecessary detail.

Claims

1. A 3D printing system, comprising:

a film (110) for adhering to a printed sample to be cured under irradiation of the optical engine (102);

a membrane separator (120), the membrane separator (120) being movable along an upper surface of the membrane (110), the membrane separator (120) comprising:

a housing (122), the housing (122) having a second cavity (122 b) on a side facing the membrane (110);

a first roller (126) rotatably installed at one side of the second cavity (122 b);

a vacuum source connected to the housing (122) for generating a negative pressure in the second cavity (122 b);

2. The 3D printing system according to claim 1, wherein the material of the first roller (126) and the second roller (128) is a metallic material, a ceramic material or a combination of metallic and ceramic material, and the surface of the first roller (126) and/or the second roller (128) is coated with a protective layer.

3. The 3D printing system according to claim 1, wherein the first roller (126) and the second roller (128) are both installed in the second cavity (122 b) through bearings (126 c), and the distance between the inner wall of the second cavity (122 b) and the outer walls of the first roller (126) and the second roller (128) is 50 [ mu ] m-100 [ mu ] m; the axial center distance between the first roller and the second roller is 12.5mm, which is 2.5-3 times of the diameter of the rollers; the width of the first space is 7.5mm and is 1.5-2 times of the diameter of the roller.

4. The 3D printing system according to claim 1, wherein the first roller and the second roller cooperate to form a gap of 7.5mm, 1.5-2 times the roller diameter, the buffer chamber restricting air flow between the buffer chamber (124) and the second cavity (122 b) of the housing (122) in an array of 10 x 500 μm apertures, the first roller and the second roller being two parallel rollers of 5mm diameter and 7.5mm apart.

5. The 3D printing system according to claim 4, wherein the third cavity (241 a) is adjacent to the second cavity (122 b) and communicates through a number of the apertures (124 b), a number of the apertures (124 b) are aligned along an axial direction of the first roller (126), and the apertures (124 b) are aligned in a middle of the second cavity (122 b).

6. The 3D printing system of any of claims 1-5, further comprising:

a resin tank (108) for storing printing consumables;

an optical engine (102) for projecting an image to cure the printing consumable;

and a sample carrying table (112) which is arranged in the resin tank (108) and is connected with a multi-shaft driving mechanism.

7. The 3D printing system of claim 6, further comprising: a control computer (106) for controlling the movement of the multi-axis drive mechanism, the optical engine (102), the membrane separator (120), and the membrane (110).

8. The 3D printing system according to claim 6, wherein a lens (104) is provided below the optical engine (102).

9. A 3D printing method, comprising the steps of:

printing a layer of resin on the lower surface of the film;

a membrane separator (120) is provided, the membrane separator (120) comprising:

a housing (122), the housing (122) having a second cavity (122 b) on the side facing the membrane (110);

activating the vacuum source and then moving the membrane separator (120) along the upper surface of the membrane (110) to progressively separate the membrane (110) from the printed layer of resin;

10. The 3D printing method according to claim 9, wherein after one layer is cured, the film separator (120) is left away from the printed sample (140) and a vacuum environment is created to hold the film (110) against the first roller (126) and the second roller (128),

next, the sample stage (112) is moved upward, i.e., in the direction of the lens (104), to define the thickness of the next layer, the membrane separator 120 is returned to the original position, the above process is repeated as the membrane 110 is flattened due to membrane tension or other coating technique, and the next layer image is projected onto the membrane (110), repeating the above steps until the complete printed sample (140) is replicated in the resin tank 108.