Release-film-free rapid photocuring 3D printing device and method

Abstract

The invention provides a release-film-free rapid photocuring 3D printing method. The release-film-free rapid photocuring 3D printing method comprises the following steps that photosensitive resin is added into a resin trough; the printing chamber is inversely buckled and fixed in the resin trough, so that a liquid level difference is generated between the liquid level in the printing chamber and the liquid level in the resin trough, and a positive pressure or negative pressure air environment is formed in the printing chamber; setting printing parameters of the three-dimensional model through slicing software, and importing the printing parameters into a control system; patterns displayed on a display screen of a projection device are exposed and cured at the liquid level of a printing cavity layer by layer through a control system, after exposure of each layer is completed, the control system controls a servo motor to drive a lifting module to act, and then a printing platform is driven to descend by the distance of one layer thickness; the liquid level in the printing cavity is fast and stable, the steps are repeated, and exposure curing of the next layer is carried out until printing forming of the model is completed; and the formed model on the printing platform is taken out, and residual resin on the surface is cleaned through ultrasonic treatment. According to the release-film-free rapid photocuring 3D printing method, in the 3D printing process, the liquid level can be rapidly stabilized, no bubble is generated, and the 3D printing efficiency and the product surface precision are remarkably improved. The invention further provides a release-film-free rapid photocuring 3D printing device.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a release film-free rapid light-curing 3D printing device and method. Background Art

[0002] In recent years, photocuring 3D printing technology has developed rapidly and has been widely used in fields such as medicine, electronics, aerospace, and industrial manufacturing. However, traditional photocuring 3D printing technology usually uses release film to assist molding, so the model needs to be separated from the release film and adhered to the building substrate through the reciprocating motion of the printing platform. This process significantly increases the printing time and reduces the printing efficiency. Continuous liquid interface curing technology (CLIP) solves the above problems by using a gas-permeable membrane, but the cost of the gas-permeable membrane is expensive, which limits the popularization and application of this technology. In addition, repeated use of the release film will cause surface wear, which in turn affects the stability of the printing process and even causes printing failure. Therefore, the maintenance and replacement of the release film further increases the production cost and operational complexity, which is not conducive to the promotion and application of photocuring 3D printing technology in industrial production.

[0003] In the prior art, in order to solve the problems existing in the release film in 3D printing technology, the sinking 3D printing technology has been promoted and applied. For example, the Chinese patent application (CN111688187A) discloses a projection device, a printer and a light control method based on an LCD liquid crystal display screen. This technology adopts the sinking 3D printing technology to improve the printing success rate and efficiency of the product by optimizing the optical path structure, but this technical solution has the common problems of the sinking 3D printing technology: on the one hand, after completing a layer of printing, the lifting mechanism drives the printing platform to descend, and the liquid level will fluctuate during the process. It is necessary to wait for the liquid level to stabilize before printing the next layer, which affects the work efficiency. If the next layer is printed when the liquid level is not stable, the problem of uneven printing thickness will occur, affecting the printing accuracy; on the other hand, since the 3D printing material used is a light-curing resin, the liquid level fluctuation will generate bubbles on the liquid surface during the process of the lifting mechanism driving the printing platform to descend, and the next layer of printing needs to be defoamed before printing, otherwise it will also affect the printing accuracy. The defoaming process of bubbles on the liquid surface takes a long time, especially the bubbles generated by high-viscosity resins are more difficult to eliminate, which seriously affects the efficiency of 3D printing.

[0004] In view of this, it is necessary to provide a fast light-curing 3D printing process with high efficiency and high printing accuracy to solve the above technical problems. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a release film-free rapid photocuring 3D printing device and method, which adopts the sinking 3D printing technology to effectively overcome the technical defects of the release film in 3D printing. At the same time, during the 3D printing process, the liquid surface can be quickly stabilized and no bubbles are generated, which significantly improves the efficiency of 3D printing and the surface accuracy of the product.

[0006] The first aspect of the present invention is to provide a release film-free rapid light-curing 3D printing device, and the technical solution thereof is as follows:

[0007] A release film-free rapid light-curing 3D printing device, comprising a resin tank for containing photosensitive resin, a printing chamber, a projection device arranged in the printing chamber, a lifting module, a printing platform arranged at one end of the lifting module, a servo motor for controlling the operation of the lifting module, and a control system;

[0008] The printing chamber is a hollow structure with one end open. When working, the open end of the printing chamber is inverted and fixed above the resin tank, so that a liquid level difference is generated between the liquid level in the printing chamber and the liquid level in the resin tank, and a positive pressure or negative pressure air environment is formed in the printing chamber; the printing platform is located below the liquid level of the printing chamber;

[0009] The printing parameters of the three-dimensional model are imported into the control system, and the control system exposes and solidifies the printed pattern layer by layer at the liquid surface in the printing chamber through a projection device, and controls the servo motor to drive the lifting module to move after the exposure and curing are completed, thereby driving the printing platform to move downward to expose and solidify the next layer of graphics, and the distance the printing platform descends each time is equal to the thickness of the corresponding printing layer.

[0010] Furthermore, the projection device comprises an LCD screen and an ultraviolet light source, and the LCD screen is located above the liquid level in the printing chamber.

[0011] Furthermore, the wavelength of the ultraviolet light source is 405 nm.

[0012] Furthermore, the printing parameters include exposure time and layer thickness.

[0013] The second aspect of the present invention is to provide a release film-free rapid light-curing 3D printing method, the technical solution of which is as follows:

[0014] A release film-free rapid light-curing 3D printing method, using the 3D printing device described in the first aspect, the 3D printing method comprises the following steps:

[0015] Step S1, adding photosensitive resin into the resin tank;

[0016] Step S2, fixing the printing chamber upside down in the resin tank, so that a liquid level difference is generated between the liquid level in the printing chamber and the liquid level in the resin tank, and forming a positive pressure or negative pressure air environment in the printing chamber;

[0017] Step S3, setting the printing parameters of the three-dimensional model through the slicing software and importing it into the control system;

[0018] Step S4, the control system exposes and solidifies the pattern displayed on the display screen of the projection device layer by layer at the liquid surface of the printing chamber. After each layer is exposed, the control system controls the servo motor to drive the lifting module to move, thereby driving the printing platform to descend a layer thickness;

[0019] Step S5, the liquid level in the printing chamber is quickly stabilized, and step S4 is repeated to perform exposure and curing of the next layer until the printing of the model is completed;

[0020] Step S6, taking out the formed model on the printing platform and cleaning the residual resin on the surface by ultrasonic treatment.

[0021] Furthermore, in step S3, a three-dimensional model is constructed by using a three-dimensional modeling software, and an STL file is exported, and the STL file is imported into a light-curing 3D printing slicing software to set printing parameters.

[0022] Furthermore, the printing parameters include exposure time and layer thickness.

[0023] Furthermore, the projection device comprises an LCD screen and an ultraviolet light source, and the LCD screen is located above the liquid level in the printing chamber.

[0024] Furthermore, the wavelength of the ultraviolet light source is 405 nm.

[0025] Furthermore, in step S6, the ultrasonic cleaning step uses an ethanol solution for cleaning for 5 minutes.

[0026] Compared with the prior art, the release film-free rapid light-curing 3D printing device and method provided by the present invention have the following beneficial effects:

[0027] 1. The release film-free rapid light-curing 3D printing device and method provided by the present invention fixes the printing chamber upside down on the top of the resin tank, so that the liquid level in the resin tank and the liquid level in the printing chamber have a liquid level difference, thereby forming a positive pressure or negative pressure air environment in the printing chamber. Since the gas volume in the printing chamber remains unchanged, the liquid level in the printing chamber can be quickly stabilized during the light-curing 3D printing process, thereby avoiding the problem of uneven layer thickness and the problem of bubbles on the liquid surface caused by the unstable liquid level during the printing process, and improving the surface accuracy of the product. Since the liquid level in the printing chamber can be quickly stabilized, the adjustment time of waiting for the liquid level to return to stability is saved, and the printing efficiency is improved.

[0028] 2. The release film-free rapid light-curing 3D printing device and method provided by the present invention sets the printing parameters through the slicing software and imports them into the control system. The control system accurately controls the exposure time of each layer and the distance that the servo motor drives the printing platform to descend to ensure that the air pressure in the printing chamber remains unchanged, thereby ensuring the curing accuracy of each layer, reducing the defects of the model and the problem of layer separation, and thus significantly improving the surface molding quality of the model.

[0029] 3. When the liquid level of the photocurable resin fluctuates, bubbles will be generated on the liquid surface, and the greater the viscosity of the resin material, the more difficult it is to eliminate the bubbles. The release-free film-free rapid photocuring 3D printing device and method provided by the present invention can quickly stabilize the liquid level in the printing chamber, thus avoiding the problem of bubbles generated by liquid level fluctuations. Therefore, it can be applied to photosensitive resins with different viscosity ranges, providing a wider range of material choices for various application scenarios, expanding the application field of photocuring 3D printing technology, and meeting diversified production needs. At the same time, the release-free film-free rapid photocuring 3D printing device and method provided by the present invention does not need to set a bubble scraper to eliminate bubbles, making the structure of the printing device simpler, and more capable of achieving continuous operation, thereby ensuring printing efficiency.

[0030] 4. The release film-free rapid light-curing 3D printing device and method provided by the present invention do not require the use of a release film, thereby eliminating the purchase, maintenance and replacement costs of the release film, while simplifying the structure and maintenance operations of the equipment and reducing the overall production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 3. It is a schematic structural diagram of a release film-free rapid light-curing 3D printing device of the present invention;

[0033] Figure 2 is a light microscope image of a molded part obtained by the method of Example 2;

[0034] Figure 3 is a schematic structural diagram of a light-curing 3D printing device of Example 3;

[0035] Figure 4 This is a light microscope image of the molded part obtained by the method of Example 3. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific implementation modes of the present invention are further described below.

[0037] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0038] Example 1

[0039] See also Figure 1 , is a schematic diagram of the structure of the release film-free rapid light-curing 3D printing device of the present invention. The release film-free rapid light-curing 3D printing device of the present invention comprises a resin tank 1, a printing chamber 2, a projection device 3, a lifting module 4, a printing platform 5, a servo motor 6, and a control system (not shown).

[0040] The resin tank 1 is used to contain light-curing resin material. The use of the light-curing resin is selected according to the application field and application scenario of the model.

[0041] The printing chamber 2 is a hollow structure with an open end. The open end is inverted on the top of the resin tank 1 in the working state. The light-curable resin material in the resin tank 1 seals the printing chamber 2, while there is air inside the printing chamber. Due to the pressure difference between the external air pressure and the air pressure in the printing chamber, there will be a liquid level difference between the liquid level in the resin tank 1 and the liquid level in the printing chamber. The depth of the printing chamber inverted in the resin material determines the pressure of the gas in the printing chamber, so that a positive pressure or negative pressure air environment can be formed in the printing chamber.

[0042] The projection device 3 is arranged in the printing chamber 2, and includes an LCD screen 31 with high resolution and an ultraviolet light source 32. The LCD screen is located above the liquid surface in the printing chamber, and the wavelength of the ultraviolet light source is 405nm. The three-dimensional model is constructed by three-dimensional modeling software, and the STL file is exported. The STL file is imported into the photocuring 3D printing slicing software to set the printing parameters, and the printing parameters are imported into the control system. When working, the ultraviolet light source 32 is turned on, and a pattern corresponding to the printed model is displayed on the LCD screen, and the ultraviolet light source is irradiated to expose and cure at the liquid surface of the printing chamber. The exposed and cured graphics are the same as the graphics displayed on the LCD screen. When setting the printing parameters, the corresponding exposure time is designed according to the thickness of each layer and the information of the resin material used to accurately control the layer thickness of the printed model.

[0043] The lifting module 4 is controlled by a servo motor 6 and has the characteristics of high control accuracy. The servo motor 6 is controlled by a control system. One end of the lifting module 4 is connected to the printing platform 5, thereby driving the printing platform 5 to perform lifting and lowering movements. Among them, the printing platform is used to carry the printing model. After a layer of exposure and curing is completed, the servo motor drives the lifting module to work, driving the printing platform 5 to descend, and the descending height is equal to the thickness of the corresponding printing layer. In the present invention, the lifting module 4 is a screw rod and a nut. Its working principle is: the servo motor provides power, drives the pulley to rotate through the reducer, and the pulley drives the screw rod to rotate, so that the nut produces a linear motion. The printing platform 5 is connected to the nut by a connecting rod, so that the lifting and lowering linear motion of the printing platform can be realized. The present invention adopts a servo motor to control the descending distance of the lifting platform, and the control accuracy is high, so that the layer thickness error can be controlled within the micron range.

[0044] When the model printing is completed, the printing chamber can be removed, and the lifting module can be driven up to expose the molded model to the resin liquid surface, so that the molded model can be taken out.

[0045] Example 2

[0046] Based on the release film-free rapid light-curing 3D printing device described in Example 1, the present invention further provides a release film-free rapid light-curing 3D printing method, which specifically includes the following steps:

[0047] Step S1, adding photosensitive resin into the resin tank;

[0048] Step S2, fixing the printing chamber upside down in the resin tank, so that a liquid level difference is generated between the liquid level in the printing chamber and the liquid level in the resin tank, and forming a positive pressure or negative pressure air environment in the printing chamber;

[0049] Step S3, setting the printing parameters of the three-dimensional model through the slicing software and importing it into the control system;

[0050] Specifically, a 3D model is constructed using 3D modeling software, and an STL file is exported. The STL file is imported into a light-curing 3D printing slicing software to set printing parameters, where the printing parameters include layer thickness, exposure time of each layer, etc., to ensure the curing accuracy of the model.

[0051] Step S4, the control system exposes and solidifies the pattern displayed on the display screen of the projection device layer by layer at the liquid surface of the printing chamber. After each layer is exposed, the control system controls the servo motor to drive the lifting module to move, thereby driving the printing platform to descend a layer thickness;

[0052] Specifically, the control system controls the projection device to start, the ultraviolet light source to start, and the pattern corresponding to the printed model is displayed on the LCD screen. The ultraviolet light source is irradiated to expose and cure the liquid surface in the printing chamber, and the exposed and cured pattern is the same as the pattern displayed on the LCD screen. The wavelength of the ultraviolet light source is 405nm.

[0053] When the lifting module drives the printing platform down a layer thickness, the next layer can be exposed and cured.

[0054] Step S5, the liquid level in the printing chamber is quickly stabilized, and step S4 is repeated to perform exposure and curing of the next layer until the printing of the model is completed;

[0055] Step S6, taking out the formed model on the printing platform, and cleaning the residual resin on the surface by ultrasonic treatment. Specifically, the ultrasonic treatment cleaning step uses ethanol solution to clean for 5 minutes to remove the residual photosensitive resin on the surface of the printed model to ensure the cleanliness of the model.

[0056] The optical microscope image of the molded part printed in this embodiment is as follows Figure 2 As shown by Figure 2 It can be seen that the surface quality of the molded model is high and there is no obvious layer pattern.

[0057] Example 3

[0058] A method for rapid photocuring 3D printing without release film, using Figure 3 The light-curing 3D printing device shown includes the following steps:

[0059] Step S1, adding photosensitive resin into a resin tank;

[0060] Step S2, importing the slice file into the control system;

[0061] Step S3, using the sinking 3D printing technology to solidify the photosensitive resin at the liquid surface layer by layer. After one layer is exposed and solidified, the lifting device drives the printing platform to descend, and then the next layer is exposed and solidified until the printing of the model is completed;

[0062] Step S4, taking out the formed model and performing ultrasonic cleaning for 5 minutes.

[0063] The optical microscope image of the molded part printed in this embodiment is as follows Figure 4 As shown by Figure 4 It can be seen that the surface of the molded model has obvious layer patterns.

[0064] The release film-free rapid light-curing 3D printing device and method of the present invention fixes the printing chamber upside down in the resin material tank, so that a liquid level difference is generated between the liquid level in the printing chamber and the liquid level in the resin material tank. During the 3D printing process, the liquid level can be quickly stabilized and no bubbles are generated, which significantly improves the efficiency of 3D printing and the surface accuracy of the product.

[0065] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations made to these embodiments without departing from the principles of the present invention are still within the scope of protection of the present invention.

Claims

1. A release film-free rapid light-curing 3D printing device, characterized in that: It includes a resin tank for containing photosensitive resin, a printing chamber, a projection device arranged in the printing chamber, a lifting module, a printing platform arranged at one end of the lifting module, a servo motor for controlling the operation of the lifting module, and a control system; The printing chamber is a hollow structure with one end open. When working, the open end of the printing chamber is inverted and fixed above the resin tank, so that a liquid level difference is generated between the liquid level in the printing chamber and the liquid level in the resin tank, and a positive pressure or negative pressure air environment is formed in the printing chamber; the printing platform is located below the liquid level of the printing chamber; The printing parameters of the three-dimensional model are imported into the control system, and the control system exposes and solidifies the printed pattern layer by layer at the liquid surface in the printing chamber through a projection device, and controls the servo motor to drive the lifting module to move after the exposure and curing are completed, thereby driving the printing platform to move downward to expose and solidify the next layer of graphics, and the distance the printing platform descends each time is equal to the thickness of the corresponding printing layer.

2. The release film-free rapid light-curing 3D printing device according to claim 1, characterized in that: The projection device comprises an LCD screen and an ultraviolet light source, and the LCD screen is located above the liquid level in the printing chamber.

3. The release film-free rapid light-curing 3D printing device according to claim 2, characterized in that: The wavelength of the ultraviolet light source is 405 nm.

4. The release film-free rapid light-curing 3D printing device according to claim 1, characterized in that: Printing parameters include exposure time and layer thickness.

5. A method for rapid photocuring 3D printing without release film, characterized in that: Using the 3D printing device of claim 1, the 3D printing method comprises the following steps: Step S1, adding photosensitive resin into the resin tank; Step S2, fixing the printing chamber upside down in the resin tank, so that a liquid level difference is generated between the liquid level in the printing chamber and the liquid level in the resin tank, and forming a positive pressure or negative pressure air environment in the printing chamber; Step S3, setting the printing parameters of the three-dimensional model through the slicing software and importing it into the control system; Step S4, the control system exposes and solidifies the pattern displayed on the display screen of the projection device layer by layer at the liquid surface of the printing chamber. After each layer is exposed, the control system controls the servo motor to drive the lifting module to move, thereby driving the printing platform to descend a layer thickness; Step S5, the liquid level in the printing chamber is quickly stabilized, and step S4 is repeated to perform exposure and curing of the next layer until the printing of the model is completed; Step S6, taking out the formed model on the printing platform and cleaning the residual resin on the surface by ultrasonic treatment.

6. The release film-free rapid light-curing 3D printing method according to claim 5, characterized in that: In step S3, a three-dimensional model is constructed by using a three-dimensional modeling software, and an STL file is exported, and the STL file is imported into a light-curing 3D printing slicing software to set printing parameters.

7. The method for rapid photocuring 3D printing without release film according to claim 6, characterized in that: Printing parameters include exposure time and layer thickness.

8. The release film-free rapid light-curing 3D printing method according to claim 5, characterized in that: The projection device comprises an LCD screen and an ultraviolet light source, and the LCD screen is located above the liquid level in the printing chamber.

9. The method for rapid photocuring 3D printing without release film according to claim 8, characterized in that: The wavelength of the ultraviolet light source is 405 nm.

10. The method for rapid photocuring 3D printing without release film according to any one of claims 5 to 9, characterized in that: In step S6, the ultrasonic cleaning step uses an ethanol solution for cleaning for 5 minutes.

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