A large-area continuous photocuring 3D printing device and a printing method thereof

Abstract

The application discloses a large-area continuous photocuring 3D printing device and a printing method thereof, and belongs to the technical field of 3D printing devices. The device comprises a printing platform, wherein the printing platform is connected with a platform support, a resin tank is arranged below the printing platform, a film is arranged in the resin tank, a projector is arranged below the outside of the resin tank, the projector comprises a plurality of projectors, a plurality of through holes corresponding to the projection centers of the projectors are arranged on the printing platform, a plurality of film deformation supporting components are arranged between the printing platform and the resin tank, the upper end of the film deformation supporting component is connected with the platform support, and the lower end of the film deformation supporting component is in contact with the film. The application can effectively reduce the deformation of the film caused by stress, improve the printing quality, and increase the printing size. The application eliminates the dependence of the printing size of a DLP printer on the hardness of the film, and greatly improves the printing size of the DLP printer. In combination with the printing method, the continuous forming of 3D objects with any size is realized.

Description

Technical Field

[0001] This invention relates to a large-area continuous photopolymerization 3D printing device and its printing method, belonging to the technical field of 3D printing devices. Background Technology

[0002] Additive manufacturing, commonly known as 3D printing, integrates computer-aided design, materials processing and forming technologies. Based on digital model files, it uses software and CNC systems to layer specialized metallic, non-metallic, and medical biomaterials through methods such as extrusion, sintering, melting, photopolymerization, and spraying to create physical objects. Unlike traditional processing methods that involve removing raw materials—cutting and assembling—it is a bottom-up manufacturing method that adds materials from scratch. This makes it possible to manufacture complex structural components that were previously impossible due to the constraints of traditional manufacturing methods.

[0003] DLP (Digital Light Processing) printers are an additive manufacturing method that uses a projector to illuminate photosensitive resin, causing it to solidify. The main working process of a DLP printer is as follows: the printing platform descends, the projector projects the image once, the printing platform rises and then descends again, the projector projects the image again, and this process is repeated. Because this method is relatively slow, continuous DLP printers have emerged: these eliminate the reciprocating motion, and the platform rises slowly and uniformly from the start of printing, while the projector synchronously changes the illuminated pattern. As long as the rising process and the illumination of the printing surface are synchronized, the part printing can be completed.

[0004] However, this continuous printing method also brings new problems. Because the lower surface of the model cures on the film, the resin material is very viscous. During the ascent of the printing platform, it exerts an upward force on the film, causing deformation and resulting in distorted projected images and poor printing quality. This is especially true for 3D printers with multiple projectors, where film deformation can cause overlap and distortion at the seams of the projected images. Traditional DLP printers, which operate on a reciprocating motion, delay for a few seconds before the projector lights up, allowing the resin and film to fully stabilize, thus avoiding deformation issues. Therefore, current high-speed continuous DLP printers can only use one projector, and due to the limited light intensity of the projector, the printing area is relatively small. There is currently no good solution, and the larger DLP printers on the market are generally around 200mm*120mm in size. As the projected area increases, the light intensity decreases rapidly. For example, if the area increases from 192mm*120mm to 384*240mm, the light intensity drops to one-quarter, which is insufficient for curing. To significantly increase the printing area, multiple projectors must be used in combination.

[0005] The larger the area, the greater the film deformation when the platform rises, which can lead to distortion and overlap in multi-optical image stitching, affecting accuracy. There are limitations on the film's thickness and hardness; excessive increases will worsen light transmission and slow down printing speed. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a large-area continuous photopolymerization 3D printing device, which solves the problems existing in the prior art.

[0007] The present invention discloses a large-area continuous photopolymerization 3D printing device, comprising a 3D printing device body, a printing platform, a platform support connected to the printing platform, and the printing platform being raised and lowered via the platform support. A resin tank is located below the printing platform, containing a membrane. Multiple projectors are located below and outside the resin tank. Multiple through-holes corresponding to the projection centers of the projectors are provided on the printing platform. Multiple membrane deformation support components are located between the printing platform and the resin tank. The upper ends of the membrane deformation support components are connected to the platform support, and the lower ends of the membrane deformation support components are in contact with the membrane.

[0008] Furthermore, the membrane deformation support component is a membrane deformation stabilizing rod, with the upper end of the membrane deformation stabilizing rod fixed and the lower end of the membrane deformation stabilizing rod passing through the through hole of the platform support and placed on the membrane.

[0009] Furthermore, a hanging ring is provided above the printing platform, and the printing platform is fixed to the platform support by the hanging ring.

[0010] Furthermore, the contact point between the membrane deformation stabilizer and the membrane is made of a soft rubber material.

[0011] Furthermore, the printing platform has three projectors, three membrane deformation stabilizing rods, and three through holes, each corresponding to the projection center of one of the three projectors.

[0012] Furthermore, the printing platform has 9 projectors, 9 film deformation stabilizing rods, and 9 through holes, each corresponding to the projection center of one of the 9 projectors.

[0013] The printing method of the large-area continuous photopolymerization 3D printing device of the present invention includes the following steps:

[0014] Step 1: During operation, resin flow, filling, and curing occur simultaneously during dynamic printing. First, calculate the entire projection window, with a width W and a height H. Each pixel is marked as p, and its position is (p...). x p y ), 0 < p x <W, 0<p y <H), areas with projection are displayed in white (p=1), and blank areas are displayed in black (p=0). Set the printing parameters t and t0. c The value.

[0015] Step 2: Divide the entire projection region into nW ×n H A small piece B ij , (0 < i < n W , 0 < j < n H ), calculate the fill ratio of the white area in each small block. Where D wi D represents the number of white pixels in the i-th block. i This represents the total number of pixels in the small block.

[0016] W ij =∑p, p∈B ij

[0017]

[0018] Step 3: If the fill ratio r ij >t, retrieve the small block B ij center coordinates

[0019] Step 4: For the center coordinates that satisfy the conditions in Step 3 Calculate the proportion of white fill around the perimeter. in

[0020]

[0021]

[0022] In the formula, R is the pixel length of the circle's radius, generally... If the fill ratio of any area that meets the conditions If the print mode is reversed, the print mode will be activated; otherwise, the print mode will be activated by default and the print mode will be activated continuously.

[0023] Step 4, the reciprocating printing of the model, includes: raising the platform by x millimeters, then lowering it by x-δ millimeters, exposing and curing, increasing z by δ, and then slicing the next layer; if the conditions are not met... At the center point, the platform continues to rise, z continues to increase, the image continues to change, and continuous printing is performed.

[0024] The installation method of a large-area continuous photopolymerization 3D printing device according to the present invention includes the following steps:

[0025] During installation, first install the printing platform on the platform bracket, then pass the membrane deformation support component from top to bottom through the gap between the printing platforms, gently contact the membrane and fix it on the vertical axis, so that the membrane does not bear the weight of the membrane deformation support component.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention discloses a large-area continuous photopolymerization 3D printing device, which effectively reduces film deformation caused by stress, improves print quality, and increases print size. This invention eliminates the dependence of DLP printer print size on film hardness, significantly increasing the print size of DLP printers. Combined with the printing method, it enables continuous forming of 3D objects of arbitrary shapes. It solves the problem of film deformation during printing platform elevation in existing technologies. Through a special structure, support is added above the film, and with the corresponding printing algorithm, film deformation is reduced, lowering the requirement for film hardness. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the first embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the second embodiment of the present invention;

[0030] Figure 3 This is a structural diagram of the printing platform in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the printing platform and platform support in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of the membrane deformation stabilizing bar and the printing platform in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure of the membrane deformation stabilizing rod and the membrane in an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the installation structure of the device in an embodiment of the present invention;

[0035] Figure 8 This is a flowchart of the printing method in an embodiment of the present invention;

[0036] In the diagram: 1. Platform support; 2. Membrane; 3. Resin tank; 4. Membrane deformation stabilizing bar; 5. Printing platform; 6. Projector; 7. Hanging ring; 8. Through hole; 9. Rubber material. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0038] Example 1:

[0039] like Figure 1As shown, the large-area continuous photopolymerization 3D printing device of the present invention includes a printing platform 5, which is connected to a platform support 1. The printing platform 5 can be raised and lowered through the platform support 1. A resin tank 3 is provided below the printing platform 5, and a membrane 2 is provided inside the resin tank 3. A projector 6 is provided below the outside of the resin tank 3. The projector 6 includes multiple projectors. The printing platform 5 is provided with multiple through holes 8 corresponding to the projection center of the projector 6. Multiple membrane deformation support components are provided between the printing platform 5 and the resin tank 3. The upper end of the membrane deformation stabilizing rod 4 is fixed, and the lower end of the membrane deformation stabilizing rod 4 passes through the through hole 8 of the platform support 1 and is placed on the membrane 2.

[0040] The lower end of the membrane deformation support component is in contact with membrane 2.

[0041] The membrane deformation support component is a membrane deformation stabilizing rod 4, and the upper end of the membrane deformation stabilizing rod 4 passes through the through hole 8 and is connected to the platform support 1.

[0042] A hanging ring 7 is provided above the printing platform 5, and the printing platform 5 is fixed to the platform support 1 by the hanging ring 7.

[0043] The contact point between the membrane deformation stabilizer 4 and the membrane 2 is made of soft rubber material 9.

[0044] There are 3 projectors corresponding to the printing platform 5, 3 membrane deformation stabilizing rods 4, and 3 through holes 8 on the printing platform 5, which correspond to the projection centers of the 3 projectors 6 respectively.

[0045] The working principle of this embodiment is as follows:

[0046] Because the lower surface of the model solidifies on the film, the resin material is very viscous. During the upward movement of the printing platform, it exerts an upward force on the film, causing deformation and resulting in distorted projected images and poor printing quality. This is especially true for 3D printers with multiple projectors, where film deformation can cause overlap and distortion at the seams of the projected images. In contrast, traditional DLP printers, which operate on a reciprocating motion, delay for a few seconds before the projector lights up to allow the resin and film to fully stabilize, thus avoiding deformation issues. Therefore, current high-speed continuous DLP printers can only use one projector, and their printing area is limited by the projector's light intensity.

[0047] The device of this invention is equipped with multiple projectors. To reduce the deformation of the membrane caused by upward force, several stress points are added above the membrane to counteract the force exerted when the printing platform rises. These stress points can be avoided by changing the placement of the model; if they cannot be avoided, they can be compensated for through post-processing of the model. Through a special structure, support is added above the membrane, reducing membrane deformation and lowering the requirement for membrane stiffness.

[0048] Example 2:

[0049] Based on Example 1, such as Figure 2-6 As shown, the printing platform has 9 projectors, 9 membrane deformation stabilizing rods, and 9 through holes, each corresponding to the projection center of one of the 9 projectors.

[0050] The working principle of this embodiment is as follows: Taking a large-area 3D printer with a 3x3 projector array as an example, the printing platform has 9 through holes, corresponding to the projection centers of the 9 projectors, minimizing deformation to the greatest extent. The upper part of the printing platform has hanging rings for fixing the printing platform to the platform support.

[0051] like Figure 4 As shown, the printing platform is fixed to the platform support by a hanging ring.

[0052] like Figure 5 As shown, the membrane deformation stabilizing rod passes through the through-hole on the printing platform. The membrane deformation stabilizing rod is coated with a lubricating coating such as polytetrafluoroethylene, which supports the membrane without affecting the movement of the printing platform.

[0053] like Figure 6 As shown, the membrane deformation stabilizer supports the membrane and reduces its deformation when subjected to upward forces. A soft rubber material is used at the contact point between the membrane deformation stabilizer and the membrane to minimize damage.

[0054] Example 3:

[0055] like Figure 7 As shown, the printing method of the large-area continuous photopolymerization 3D printing device of the present invention includes the following steps:

[0056] During installation, first install the printing platform 5 on the platform bracket 1. The upper end of the film deformation stabilizing rod 4 is fixed on the vertical axis, and the lower end of the film deformation stabilizing rod 4 passes through the through hole 8 of the platform bracket 1 and is placed on the film 2. Then, the film deformation support component passes through the gap between the printing platforms 5 from top to bottom and makes light contact with the film 2, so that the film 2 does not bear the weight of the film deformation support component. When the printing platform 5 moves, the film deformation stabilizing rod 4 does not move.

[0057] After printing, remove the platform and stabilizer bar together. If using a rigid resin material, pull out the film deformation stabilizer bar from bottom to top, then separate the printed part from the platform. If using a flexible resin material, cure the platform, support bar, and material together, using the stabilizer bar to support the large flexible printed part. Separate the parts after curing. Because the film deformation stabilizer bar is coated with a lubricating coating such as PTFE, it will not stick to the printed part.

[0058] Example 4:

[0059] like Figure 8 As shown, the printing method of the large-area continuous photopolymerization 3D printing device of the present invention includes the following steps:

[0060] Step 1: During operation, resin flow, filling, and curing occur simultaneously during dynamic printing. First, calculate the entire projection window, with a width W and a height H. Each pixel is marked as p, and its position is (p...). x p y ), 0 < p x <W, 0<p y <H), areas with projection are displayed in white (p=1), and blank areas are displayed in black (p=0). Set the printing parameters t and t0. c The value of , where t represents the fill ratio r ij The threshold, t c Indicates fill ratio The threshold.

[0061] Step 2: Divide the entire projection region into n W ×n H A small piece B ij , (0 < i < n W , 0 < j < n H ), calculate the fill ratio of the white area in each small block. Where D wi D represents the number of white pixels in the i-th block. i This represents the total number of pixels in the small block.

[0062] W ij =∑p, p∈B ij

[0063]

[0064] Step 3: If the fill ratio r ij >t, retrieve the small block B ij center coordinates

[0065] Step 4: For the center coordinates that satisfy the conditions in Step 3 Calculate the proportion of white fill around the perimeter. in

[0066]

[0067]

[0068] In the formula, R is the pixel length of the circle's radius, generally... If the fill ratio of any area that meets the conditions If the print mode is reversed, the print mode will be activated; otherwise, the print mode will be activated by default and the print mode will be activated continuously.

[0069] The working principle of this embodiment is as follows:

[0070] like Figure 8 As shown, taking a printing area of ​​384*240mm as an example, W=380mm, H=240mm, and setting n... w =190, n H =120, each block is a 4 square millimeter area, for materials with high fluidity, higher printing parameters can be set: t=0.95, R=4mm, t c =0.6.

[0071] First, add resin to resin tank 3. Then, fix printing platform 5 to platform support 1 by hanging ring 7. Place film deformation stabilizing rod 4 through the top of through hole 8 of printing platform 5 and gently place the bottom end on film 2.

[0072] Start printing, calculate the 3D model slices when the height (z direction) is z=0, and calculate the fill ratio r of 190*120 small blocks. ij For those satisfying r ij Find the center coordinates of the small block with a radius greater than 0.95, and calculate the fill rate of its radius R region. Entering the up-and-down printing process: the platform is raised by x mm, then lowered by x-δ mm, exposed and cured, z increases by δ, and the next layer is sliced; if the conditions are not met... At the center point, the platform continuously rises, z continuously increases, and the image continuously changes for continuous printing. For materials with high viscosity, the corresponding parameters can be reduced, such as t = 0.9, t c =0.5.

[0073] The significance of this method lies in first identifying a single, definitive solid point that can be formed in continuous printing mode, then expanding the area around this solid point to examine the surrounding area. If a large number of solid portions remain around the solid point, it is determined that forming is not possible. This invention effectively reduces film deformation caused by stress, improves printing quality, and increases print size.

[0074] This invention eliminates the dependence of DLP printer printing size on film hardness, thus significantly increasing the printing size of DLP printers.

[0075] Combined with printing methods, it enables the continuous molding of 3D objects of arbitrary shapes.

[0076] The large-area continuous photopolymerization 3D printing apparatus and method described above in conjunction with the accompanying drawings, based on embodiments of the present invention, can effectively reduce film deformation caused by stress, improve printing quality, and increase printing size. The present invention eliminates the dependence of DLP printer printing size on film hardness, significantly increasing the printing size of DLP printers. It solves the problems existing in the prior art. However, the present invention is not limited to the described embodiments; changes, modifications, substitutions, and variations made to the embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A large-area continuous photopolymerization 3D printing device, comprising a 3D printing device body, characterized in that: The 3D printing device body includes a printing platform (5), which is connected to a platform support (1). The printing platform (5) can be raised and lowered through the platform support (1). A resin tank (3) is provided below the printing platform (5), and a membrane (2) is provided inside the resin tank (3). A projector (6) is provided below the outside of the resin tank (3). The projector (6) includes multiple projectors. The printing platform (5) is provided with multiple through holes (8) corresponding to the projection center of the projector (6). Multiple membrane deformation support components are provided between the printing platform (5) and the resin tank (3). The upper end of the membrane deformation support component is connected to the platform support (1), and the lower end of the membrane deformation support component is in contact with the membrane (2). The membrane deformation support component is a membrane deformation stabilizing rod (4). The upper end of the membrane deformation stabilizing rod (4) is fixed, and the lower end of the membrane deformation stabilizing rod (4) passes through the through hole (8) of the printing platform (5) and is placed on the membrane (2).

2. The large-area continuous photopolymerization 3D printing device according to claim 1, characterized in that: The printing platform (5) is provided with a hanging ring (7) above it, and the printing platform (5) is fixed to the platform support (1) by the hanging ring (7).

3. The large-area continuous photopolymerization 3D printing device according to claim 1, characterized in that: The contact point between the membrane deformation stabilizer (4) and the membrane (2) is made of soft rubber material (9).

4. The large-area continuous photopolymerization 3D printing device according to claim 1, characterized in that: The printing platform (5) has 3 projectors, 3 membrane deformation stabilizing rods (4), and 3 through holes (8) on the printing platform (5), which correspond to the projection centers of the 3 projectors (6).

5. The large-area continuous photopolymerization 3D printing device according to claim 1, characterized in that: The printing platform (5) has 9 projectors, 9 membrane deformation stabilizing rods (4), and 9 through holes (8) on the printing platform (5), which correspond to the projection centers of the 9 projectors (6).

6. A method for installing a large-area continuous photopolymerization 3D printing device, applied to the large-area continuous photopolymerization 3D printing device according to any one of claims 1-5, characterized in that, The method includes the following steps: During installation, the printing platform (5) is first installed on the platform bracket (1), and then the membrane deformation support component passes through the gap between the printing platforms (5) from top to bottom, gently contacts the membrane (2) and is fixed on the vertical axis, so that the membrane (2) does not bear the weight of the membrane deformation support component.

7. A printing method for a large-area continuous photopolymerization 3D printing apparatus, applied to the large-area continuous photopolymerization 3D printing apparatus according to any one of claims 1-5, characterized in that, The method includes the following steps: Step 1: During operation, resin flow, filling, and curing occur simultaneously during dynamic printing. First, calculate the entire projection window, with a width W and a height H. Each pixel is marked as... The location is Areas with projections are displayed in white. Use black for blank areas. Set the printing parameters t and t c The numerical value; Step 2: Start printing, calculate the 3D model slices at height z=0, and divide the entire projection area into... a small piece , Calculate the fill ratio of the white area in each small block. ,in This represents the number of white pixels in the i-th block. This represents the total number of pixels in the small block. ； ； Step 3: If the fill ratio Get the small piece center coordinates ; Step 4: For the center coordinates that satisfy the conditions in Step 3 Calculate the proportion of white fill around the perimeter. ,in: ; ； In the formula, R is the pixel length of the circle's radius, generally... If the fill ratio of any area that meets the conditions If the print mode is set to reciprocating up and down, it will enter the reciprocating printing mode; otherwise, it will print continuously by default.

8. The printing method of a large-area continuous photopolymerization 3D printing device according to claim 7, characterized in that: The reciprocating printing mode in step 4 includes: raising the printing platform by x millimeters, then lowering it by x-δ millimeters, exposing and curing, then increasing z by δ, and proceeding to the next layer slicing; if the conditions are not met... At the center point, the platform continues to rise, z continues to increase, the image continues to change, and continuous printing is performed.

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