A slurry tank for bottom-exposure light-curing 3D printing and a preparation method and application thereof

Abstract

The application discloses a slurry tank for bottom-exposure light-curing 3D printing and a preparation method and application thereof, and belongs to the technical field of 3D printing. The preparation method of the slurry tank for bottom-exposure light-curing 3D printing disclosed by the application comprises the following steps: coating functional agents on two surfaces of a silicon-containing or fluorine-containing film respectively, drying to obtain a modified film, and then arranging the modified film on a light-transmitting bottom plate at the bottom of a slurry tank body to obtain a slurry tank for bottom-exposure light-curing 3D printing. The low-molecular-weight functional agent serves as a release agent for the contact surface with the cured layer, thereby reducing the adhesion between the cured layer and the film during the printing process. The low-molecular-weight functional agent serves as an antistatic agent for modifying the contact surface between the film and the slurry tank, thereby improving the adsorption effect between the film and the light-transmitting plate of the slurry tank, reducing the separation force suffered by the cured layer during the printing process, and improving the process reliability of bottom-exposure light-curing 3D printing.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing technology, specifically relating to a slurry tank for bottom exposure photopolymerization 3D printing, its preparation method, and its application. Background Technology

[0002] Surface exposure photopolymerization uses a UV light mask exposed by a projector to induce a liquid-solid transition in the photopolymer slurry. This technology offers high forming precision, high efficiency, and excellent surface quality, making it one of the mainstream forming methods in advanced manufacturing. Surface exposure photopolymerization is divided into two types based on the relative position of the projector and the slurry tank: top exposure (free surface exposure) with the projector above the slurry tank, and bottom exposure (constrained surface exposure) with the projector below the slurry tank. Compared to top exposure, bottom exposure requires less slurry to start printing, the height of the formed part is not limited by the slurry tank or the depth of the slurry within it, and fluctuations in the liquid within the tank do not affect the flatness of the single-layer cured product formed on the transparent substrate. Therefore, it offers higher forming precision and is currently the main form of surface exposure photopolymerization.

[0003] Bottom-exposure photopolymerization printing can be divided into three processes: exposure curing, separation, and pressing. First, a thin layer (the thickness of each layer of the printed model) of liquid photopolymer paste is constrained between the constrained surface (the bottom of the paste tank) and the worktable. UV light penetrates the transparent constrained surface and cures this paste layer, causing the new cured layer to adhere to the worktable or the previous cured layer. Second, the worktable moves the new cured layer upwards, separating it from the constrained surface. Simultaneously, new liquid paste fills the space between the worktable and the constrained surface, preparing for the next layer to cure. Finally, the worktable presses the new cured layer down until there is a gap of one layer thickness between it and the constrained surface, initiating the curing of the next layer. This layer-by-layer stacking process completes the deposition and shaping process.

[0004] Separation is a significant challenge in the entire process of bottom-exposure photopolymerization 3D printing. This process requires completely separating the newly cured layer from the constrained surface without damaging the new cured layer itself or its adhesion to the already cured layer. The force required to separate the cured layer from the constrained surface during separation (i.e., the force exerted on the cured layer) is called the separation force. Once the new cured layer is fully cured, a vacuum is created between the cured layer and the bottom of the printing tank. The critical value of the separation force is the maximum load when releasing the vacuum. Furthermore, the separation force is directly proportional to the printing area of ​​the cured layer. Excessive separation force can easily lead to adhesion failure between the old and new cured layers, resulting in part printing failure and severely limiting the printable size and process reliability of bottom-exposure photopolymerization 3D printing.

[0005] The literature [On-line force monitoring of platform ascending rapid prototyping system. Journal of Materials Processing Technology. 2005, 159: 257-264] describes laying a highly transparent, low surface energy, and highly elastic silicon film at the bottom of the slurry tank as a medium between the tank bottom and the curing layer. Although the silicon film is not easily bonded to the photocurable material due to its low surface energy, its high dielectric properties make it very easy for it to electrostatically adhere to the tank bottom. When a strong adsorption effect occurs between the silicon film and the tank bottom, the vacuum state between the curing layer and the silicon film becomes difficult to break, thus requiring a large force to separate the curing layer from the silicon film (the constrained surface). Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the present invention aims to provide a slurry tank for bottom exposure photopolymerization 3D printing, its preparation method and application, to solve the technical problem of excessive separation force in the bottom exposure photopolymerization printing process.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] This invention discloses a method for preparing a slurry tank for bottom-exposure photopolymerization 3D printing, comprising the following steps:

[0009] S1: A functional agent is coated on both surfaces of a silicon- or fluorine-containing thin film, and after drying, a modified thin film is obtained;

[0010] S2: The modified film is placed on the light-transmitting base plate at the bottom of the slurry tank body to obtain a bottom-exposure light-curing 3D printed slurry tank.

[0011] Further, in S1, the functional agent is polypropylene glycol or polyethylene glycol; the silicon-containing or fluorine-containing film is a polytetrafluoroethylene film, a polytetrafluoroethylene propylene film, or a polydimethylsiloxane film.

[0012] Furthermore, in S1, the coating thickness of the functional agent is 10–20 μm.

[0013] Furthermore, in S1, the polydimethylsiloxane film is cleaned with alcohol and dried before use.

[0014] Furthermore, in S1, the drying process involves air-drying at room temperature for 12–24 hours.

[0015] Furthermore, in S2, the modified film is bonded to the bottom of the slurry tank body using silicone rubber; the area bonded by the silicone rubber is the edge of the bottom of the slurry tank body.

[0016] Furthermore, the modified film is circular with a thickness of 0.1–0.7 mm and a diameter of 180–200 mm; the light-transmitting substrate is made of colorless and transparent quartz glass or acrylic, and the thickness of the light-transmitting substrate is 5–10 mm.

[0017] The present invention also discloses a slurry tank for bottom exposure photocuring 3D printing prepared by the above preparation method.

[0018] This invention also discloses the application of the slurry tank for bottom-exposure photopolymerization 3D printing. When performing bottom-exposure photopolymerization 3D printing using the aforementioned slurry tank, the following steps are included:

[0019] A layer of photosensitive material is constrained between the bottom of the slurry tank and the worktable in a bottom-exposure UV-curing 3D printing process. UV light penetrates the bottom of the slurry tank and cures the photosensitive material, resulting in a new cured layer. This new cured layer adheres to the worktable or the previous cured layer. Subsequently, the worktable moves the new cured layer upwards, separating it from the bottom of the slurry tank. Simultaneously, new photosensitive material fills the space between the worktable and the bottom of the slurry tank, preparing for the next layer to cure. This process is repeated until a solid part is obtained between the worktable and the bottom of the slurry tank.

[0020] Furthermore, the thickness of the photosensitive material layer is the same as the layer thickness of the 3D printed model.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention discloses a method for preparing a slurry tank for bottom-exposure photopolymerization 3D printing. A polydimethylsiloxane film is modified with a low-molecular-weight functional agent and then placed at the bottom of the slurry tank. The low-molecular-weight functional agent acts as a release agent, serving as the contact surface with the cured layer. This makes the surface smooth, clean, and easy to detach, thereby reducing the adhesion between the cured layer and the film during printing. Simultaneously, the low-molecular-weight functional agent acts as an antistatic agent, modifying the contact surface between the film and the slurry tank and improving the adsorption effect between the film and the light-transmitting plate of the slurry tank. This introduces air from the bottom of the film at the initial separation stage to disrupt the vacuum state between the cured layer and the film, reducing the separation force on the cured layer during printing and improving the printable size and process reliability of bottom-exposure photopolymerization 3D printing. The preparation method disclosed in this invention is simple to operate, easy to implement, and has low manufacturing costs, enabling industrial-scale production.

[0023] The present invention also discloses a slurry tank for bottom exposure photocuring 3D printing prepared by the above preparation method. Because it allows the low molecular weight functional agent to act as the contact surface with the curing layer, it greatly reduces the separation force during bottom exposure photocuring printing and has broad application prospects.

[0024] This invention also discloses the application of the slurry tank in the above-mentioned bottom exposure photocuring 3D printing. When performing bottom exposure photocuring 3D printing, it can reduce the separation force on the cured layer during the printing process, resulting in high-quality finished products, reliable preparation processes, and improved production efficiency and yield. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the preparation method of the slurry tank for bottom exposure photocuring 3D printing according to the present invention;

[0026] Figure 2 This is a schematic diagram of the slurry tank used in the bottom exposure photocuring 3D printing of this invention during printing;

[0027] Figure 3 This is a schematic diagram of the cured layer separation process.

[0028] Wherein: 1-Slurry tank body; 2-Photosensitive material; 3-Worktable; 4-Solid parts; 5-Modified film; 6-Silicone rubber. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] like Figure 1 As shown, this invention discloses a method for preparing a slurry tank for bottom-exposure photopolymerization 3D printing, comprising the following steps:

[0032] The surface of the silicon- or fluorine-containing film is first cleaned with alcohol and then wiped and dried with non-woven cloth. Polypropylene glycol or polyethylene glycol is then evenly coated on the cleaned and dried film surfaces with a brush. The film is then left to dry at room temperature for at least 12 to 24 hours to complete the modified film production and obtain modified film 5.

[0033] The modified film 5 is bonded to the light-transmitting base plate at the bottom of the slurry tank body 1 using silicone rubber 6, to obtain a bottom-exposure light-curing 3D printed slurry tank.

[0034] The film is a silicon- or fluorine-containing material, including films such as silicone rubber (e.g., silicone), polytetrafluoroethylene (PTFE), polytetrafluoroethylene propylene (FEP), and polydimethylsiloxane (PDMS), with a thickness of 0.1–0.7 mm. The light-transmitting base plate of the slurry tank body 1 is a material with good light transmittance, including transparent and colorless quartz glass and acrylic, with a thickness of 5–10 mm. The polypropylene glycol or polyethylene glycol is a low molecular weight polymer of type PPG400 or PEG400.

[0035] Figure 2 As shown, when performing bottom exposure photocuring 3D printing using the slurry tank of the present invention, a 0.5mm thick PDMS (polydimethylsiloxane) film is selected. The slurry tank body 1 is a circular high-transmittance container with a size of φ180mm and a height of 30mm. The PDMS film is cut into a shape with a size of φ180mm. Then, its surface is first cleaned with alcohol and then wiped and dried with non-woven cloth.

[0036] PPG400 (polyethylene glycol) was evenly coated onto the front and back surfaces of the cleaned and dried PDMS film using a brush. The film was then left to dry at room temperature for 12 hours. Once the film surface was dry, the modified film was completed, and the modified film 5 was obtained.

[0037] The modified film 5 is adhered to a rigid, light-transmitting base plate inside the slurry tank body 1 using silicone rubber 6 to complete the fabrication of the special slurry tank. For example... Figure 2 As shown, the modified film 5 is bonded to the light-transmitting base plate at the bottom of the slurry tank body 1 with silicone rubber. The bonding area of ​​the silicone rubber is concentrated at the edge 6 of the slurry tank. The photosensitive material 2 is cured under UV light and bonded to the worktable 3, finally forming a solid part 4.

[0038] The entire separation process is as follows Figure 3As shown, due to the modification of the film by the release agent PPG400, the film is smooth and easy to separate on the side facing the solid part 4; at the same time, the film is treated with the antistatic agent PPG400 to remove static electricity, making it less likely to be adsorbed with the slurry tank 1. Therefore, air can be introduced at the bottom of the film in the early stage of separation to break the vacuum state between the cured layer and the film, which greatly reduces the separation force on the cured layer during the printing process.

[0039] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a slurry tank for bottom-exposure photopolymerization 3D printing, characterized in that, Includes the following steps: S1: A functional agent is coated on both surfaces of a silicon- or fluorine-containing thin film, and after drying, a modified thin film is obtained (5). S2: The modified film (5) is placed on the light-transmitting base plate at the bottom of the slurry tank body (1) to obtain a bottom-exposure light-curing 3D printed slurry tank; In S1, the functional agent is polypropylene glycol or polyethylene glycol; the silicon-containing or fluorine-containing film is a polytetrafluoroethylene film, a polytetrafluoroethylene propylene film, or a polydimethylsiloxane film.

2. The method for preparing a slurry tank for bottom-exposure photopolymerization 3D printing according to claim 1, characterized in that, In S1, the coating thickness of the functional agent is 10~20μm.

3. The method for preparing a slurry tank for bottom-exposure photopolymerization 3D printing according to claim 1, characterized in that, In S1, the polydimethylsiloxane film is cleaned with alcohol and dried before use.

4. The method for preparing a slurry tank for bottom-exposure photopolymerization 3D printing according to claim 1, characterized in that, In S1, the drying process involves air-drying at room temperature for 12-24 hours.

5. The method for preparing a slurry tank for bottom-exposure photopolymerization 3D printing according to claim 1, characterized in that, In S2, the modified film (5) is bonded to the bottom of the slurry tank body (1) using silicone rubber (6); the area bonded by the silicone rubber (6) is the edge of the bottom of the slurry tank body (1).

6. The method for preparing a slurry tank for bottom-exposure photopolymerization 3D printing according to claim 1, characterized in that, The modified film (5) is a circle with a thickness of 0.1~0.7mm and a diameter of 180~200mm; the material of the light-transmitting base plate is colorless and transparent quartz glass or acrylic, and the thickness of the light-transmitting base plate is 5~10mm.

7. A paste tank for bottom-exposure photopolymerization 3D printing, characterized in that, The slurry tank for bottom exposure photocuring 3D printing is prepared using any one of claims 1 to 6.

8. The application of the slurry tank for bottom-exposure photopolymerization 3D printing as described in claim 7, characterized in that, When performing bottom-exposure photopolymerization 3D printing using the aforementioned slurry tank, the following steps are included: A layer of photosensitive material (2) is constrained between the bottom of the slurry tank of the bottom exposure UV curing 3D printing and the worktable (3). UV light penetrates the bottom of the slurry tank of the bottom exposure UV curing 3D printing and cures the photosensitive material (2) to obtain a new cured layer, which is then bonded to the worktable (3) or the previous cured layer. Subsequently, the worktable (3) moves the new cured layer upward and separates it from the bottom of the slurry tank of the bottom exposure UV curing 3D printing. At the same time, the new photosensitive material (2) fills the space between the worktable (3) and the bottom of the slurry tank of the bottom exposure UV curing 3D printing, preparing for the next layer to be cured. The above steps are repeated until a solid part (4) is obtained between the worktable (3) and the bottom of the slurry tank of the bottom exposure UV curing 3D printing.

9. The application of the slurry tank for bottom-exposure photopolymerization 3D printing according to claim 8, characterized in that, The thickness of the photosensitive material (2) layer is the layer thickness of the 3D printed model.

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