A 3D printer and 3D printing method with center pull-down peeling function

Abstract

This application discloses a 3D printer with a center-pull-down peeling function, comprising a worktable and a center peeling mechanism. A transmission mechanism is mounted on the worktable, and a printing platform is mounted on the transmission mechanism. Air vents are provided on the printing platform. The model is bonded to the printing platform, and a release hole communicating with the air vents is formed within the model. The suction device of the center peeling mechanism can move between a working position and a resting position. When the suction device is in the working position, it can adsorb the release film directly opposite the air vents. When the suction device is in the resting position, it is located outside the vertical projection of the printing platform. This application also discloses a 3D printing method. After printing one cured layer, the suction device moves to the working position to adsorb the release film, causing the release film to peel from the cured layer from the inside out, and simultaneously peeling from the outside in, forming a bidirectional peeling mode, thereby improving the peeling speed and printing speed.

Description

Technical Field

[0001] This invention relates to a 3D printer and a 3D printing method with a center pull-down peeling function. Background Technology

[0002] When a pull-up photopolymer 3D printer is working, after each cured layer is formed on the printing platform, the printing platform needs to be raised to separate the cured layer from the release film and to create a distance of one cured layer thickness between the cured layer and the release film, so as to facilitate the formation of the next cured layer. This process of stacking cured layers is carried out gradually until the printing of the model is completed.

[0003] Because each cured layer is sealed to the release film after printing, the cured layer and the release film are in a sealed state. During the peeling process, the cured layer needs to overcome the low-pressure area between the release film and the cured layer caused by atmospheric pressure. This makes it difficult to peel the cured layer and the release film. During the peeling process, the release film is gradually peeled off from the periphery of the cured layer to the center, resulting in low peeling efficiency and limiting the improvement of printing efficiency.

[0004] To improve the peeling efficiency between the cured layer and the release film, a tilting peeling method was developed. This method involves tilting the sprue while raising the printing platform, creating a peeling notch in the release film from one side of the cured layer. As the notch widens, the release film eventually peels completely off. While this method accelerates peeling, the tilted position makes it prone to causing photosensitive resin to overflow from the sprue. To prevent this, the depth of the sprue needs to be increased or the liquid volume reduced.

[0005] Therefore, how to accelerate the peeling of the cured layer from the release film to improve printing efficiency remains an issue that needs further improvement in photopolymer 3D printing technology. Summary of the Invention

[0006] To address the problem of low peeling efficiency between the cured layer and release film in existing technologies and improve 3D printing efficiency, this application proposes a 3D printer with a center pull-down peeling function. The printer includes a worktable and a center peeling mechanism. A transmission mechanism is mounted on the worktable, comprising a ball screw extending vertically and a connecting arm meshing with the ball screw. The free end of the connecting arm forms a working end, and a printing platform is detachably mounted on this working end. The lower surface of the printing platform forms a working surface. The connecting arm can drive the printing platform to reciprocate vertically. An air vent is formed on the printing platform, extending through both the upper and lower sides of the printing platform. The upper end of the air vent forms an air inlet, and the lower end forms an air outlet.

[0007] The central stripping mechanism includes a vacuum device, an adsorber, and a swinging device. The vacuum device is fixedly installed in the inner cavity of the worktable. The adsorber has an adsorption hole that is connected to the vacuum port of the vacuum device. The swinging device is installed on the worktable, and the adsorber is installed on the swinging device. The swinging device can drive the adsorber to swing between the working position and the resting position.

[0008] A material trough is arranged on the worktable, and the printing platform can enter the material trough and print the model on its working surface; the model is bonded to the printing platform, and a demolding hole is formed in the model. The upper end of the demolding hole is connected to the air outlet, and the demolding hole penetrates at least one curing layer downwards; when the adsorber is in the working position, the adsorbing hole is located directly below the lower port of the demolding hole; when the adsorber is in the parking position, the adsorber is located outside the projection of the printing platform in the vertical direction.

[0009] After the curing layer is completed through a release hole, the adsorber can be positioned in the working position and adsorb the release film facing the lower end of the release hole. When the transmission mechanism drives the printing platform to move upward, the release film can be peeled off from the curing layer from the inside to the outside along the lower edge of the release hole.

[0010] During the model printing process, after printing one cured layer, the swing device is activated to move the suction unit from the parking position to the working position. Utilizing the suction force generated by the vacuum device, the release film facing the lower port of the release hole is adsorbed onto the suction unit. Due to the fixing effect of the suction unit, the portion of the release film adsorbed by the suction unit remains in place. When the transmission mechanism moves the printing platform upward, the release film can create an inner peeling opening between the lower edge of the release hole and the cured layer, peeling from the inside out. Simultaneously, due to the constraint of the material tank wall, the release film can also create an outer peeling opening between the outer edge of the model and the cured layer. As the model rises, the inner peeling opening continues to expand outward, and the outer peeling opening continues to expand inward, forming a bidirectional peeling method until the outer and inner peeling openings connect, completely separating the release film from the cured layer. Because the release film can be peeled simultaneously from both inside and outside, the peeling speed of the release film is increased, thereby increasing the printing speed.

[0011] Furthermore, to avoid friction between the adsorber and the release film, which would affect the light transmittance and reduce the service life of the release film, the distance between the upper surface of the adsorber and the lower surface of the release film is 0.1-0.5 mm.

[0012] Specifically, the connecting arm has two horizontally spaced retaining arms at its end away from the ball screw. These two retaining arms extend parallel to each other and away from the ball screw, forming a platform receiving cavity between them. This platform receiving cavity has an opening facing away from the ball screw. Corresponding to each retaining arm, a slot is provided on opposite sides of the printing platform. The printing platform is inserted into this platform receiving cavity, and each retaining arm is inserted into its corresponding slot. Each retaining arm is fixed to the printing platform with bolts. In this design, the retaining arms are used to mount the printing platform onto the connecting arm, thus leaving the top of the printing platform open, allowing the air vent to extend upwards through the top of the printing platform and connect to the atmosphere.

[0013] Specifically, for ease of control, the swing device includes a swing motor, which is a servo motor. The swing motor is fixed in the inner cavity of the worktable, and the output shaft of the swing motor extends upward from the top plate of the worktable. The air inlet pipe of the adsorber is fixed on the output shaft of the swing motor.

[0014] Furthermore, the adsorber includes a circular adsorption disk with a hollow cavity inside. The center of the upper surface of the adsorption disk is recessed downwards to form an adsorption cavity with an arc-shaped bottom. Adsorption holes connect the hollow cavity and the adsorption cavity. When the adsorption disk adsorbs onto the release film, the release film will be recessed downwards and adhere tightly to the upper surface of the adsorption cavity, thereby forming a downwardly protruding depression in the corresponding area of ​​the release film. This facilitates the creation of an internal peel-off opening between the release film and the cured layer from the lower edge of the air vent, which helps to accelerate the peeling speed between the release film and the cured layer.

[0015] Secondly, this application also discloses a 3D printing method, which uses the 3D printer described in any of the above claims, and the 3D printing method includes the following steps:

[0016] (1) After the 3D model of the model to be printed is completed, a cylindrical hole area with a set diameter is calculated. The hole area can extend to at least one outer end face of the model to be printed. The outer end face is used as the starting face when printing the model. The model to be printed consists of N curing layers. The hole area extends downward from the starting face by NM curing layers, where N>M.

[0017] (2) Print the model to be printed with the outer end face as the starting face. During the printing process of the curing layer of the model, a demolding hole is formed in the hole forming area. The demolding hole is connected to the air guide hole upward; the demolding hole penetrates the lower end face of the curing layer located at the bottom.

[0018] After each cured layer is printed, the swing device is activated to move the suction unit from the resting position to the working position. The vacuum device is activated to adsorb the release film onto the suction unit. Then, the transmission mechanism is activated to lift the printing platform upward, causing the release film to peel outward along the lower edge of the release hole, while simultaneously peeling inward along the outer edge of the model, until the cured layer is completely separated from the release film. The vacuum device is then turned off, and the release film detaches from the suction unit. The swing device is activated again to move the suction unit from the working position to the resting position.

[0019] Continue printing the cured layers until NM cured layers have been printed;

[0020] (3) Complete the printing of the last M curing layers.

[0021] When printing a 3D product model using the 3D printing method described in this application, during the printing of the first NM cured layers, after each cured layer is printed, the swing device is activated to move the suction device from the resting position to the working position. Utilizing the suction force generated by the vacuum device, the release film facing the lower port of the release hole is adsorbed onto the suction device. Due to the fixing effect of the suction device, the portion of the release film adsorbed by the suction device remains in place. When the transmission mechanism drives the printing platform upward, because the air vent is directly connected to the atmosphere, the negative pressure on the release film in the area corresponding to the lower port of the release hole is eliminated. The release film can then create an inner peeling opening between the edge of the lower port of the release hole and the cured layer, peeling from the inside out. Simultaneously, due to the constraint of the material tank wall, the release film can also create an outer peeling opening between the outer edge of the model and the cured layer. As the model is raised, the inner peeling opening continues to expand and extend outward, while the outer peeling opening continues to expand and extend inward, forming a bidirectional peeling method until the outer and inner peeling openings connect, completely separating the release film from the cured layer. Because the release film can be peeled off from both the inside and outside directions simultaneously, the peeling speed of the release film is increased, thereby increasing the printing speed.

[0022] During the printing of the final M cured layers, different processing methods are used depending on the needs. When the air vent penetrates the cured layer located at the bottom of the model without affecting the model's appearance or function, a bidirectional peeling method can be used to complete the separation of the release film from the final M cured layers. However, when the air vent penetrates the cured layer located at the bottom of the model and would adversely affect the model's appearance or function, it is recommended to use the traditional method to complete the separation of the release film from the final M cured layers. That is, the air vent should not penetrate into the final M cured layers, and the final M cured layers should be used to seal the air vent. After printing the model, remove the model from the printing platform, pour out the photosensitive resin remaining in the air vent through the opening on the starting surface, and clean the air vent.

[0023] Specifically, in order to ensure that the photosensitive resin in the release pores can flow smoothly downwards during the peeling process between the release film and the cured layer, the release pores are straight and extend in the vertical direction.

[0024] Furthermore, the diameter of the perforated area is set to be ≥10mm larger than the inner diameter of the demolding hole. This design ensures that the wall thickness of the demolding hole is at least 5mm, resulting in high strength in the demolding hole area.

[0025] Specifically, the inner diameter of the stripping hole is 5-20mm. During the printing process, photosensitive resin enters the stripping hole. The inner diameter of the stripping hole should not be too small. If the inner diameter is too small, it will not only increase the resistance when the photosensitive resin flows out of the stripping hole, but also cause the photosensitive resin to solidify inside the stripping hole, thus clogging it. The inner diameter of the stripping hole should also not be too large. If the stripping hole is too large, it will easily lead to insufficient strength of the model, affecting the quality of the product.

[0026] Furthermore, the total thickness of the M cured layers is 1-5mm, and the release hole does not penetrate through these M cured layers. The bottom M cured layers form a sealing layer to seal the lower end of the release hole, ensuring the integrity of the model's appearance. When printing the last M cured layers, the release film is still peeled off from the cured layers using the traditional method, relying solely on the rise of the printing platform to complete the peeling. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of an embodiment of the 3D printer in this application.

[0028] Figure 2 yes Figure 1 A view from the center AA direction.

[0029] Figure 3 This is a schematic diagram of the connecting arm.

[0030] Figure 4 yes Figure 1 A view from the center (BB direction).

[0031] Figure 5 yes Figure 1 Enlarged view of section C.

[0032] Figure 6 This is a diagram showing the state of a 3D printer in operation.

[0033] Figure 7 This is a diagram showing the state when the release film and the cured layer have partially separated.

[0034] Figure 8 This is a diagram showing the state when the release film and the cured layer are completely separated. Detailed Implementation

[0035] Example 1

[0036] Please see Figures 1-5 A 3D printer with a center pull-down peeling function includes a worktable 11 and a center peeling mechanism 40. A transmission mechanism, employing existing mature technology, is mounted on the worktable 11. The transmission mechanism includes a vertical rod 12 fixed to the worktable 11 and a ball screw 13 rotatably mounted on one side of the vertical rod. The ball screw 13 extends vertically, and one end of a connecting arm 14 is engaged with the ball screw via a screw hole. The connecting arm 14 extends horizontally, and a printing platform 20 is detachably mounted on the end of the connecting arm 14 away from the ball screw. A servo motor 15 is mounted at the lower end of the ball screw, fixed to the vertical rod. The servo motor drives the ball screw to rotate, enabling the connecting arm to reciprocate the printing platform vertically.

[0037] An LCD screen 191 is fixedly installed on the top plate 111 of the workbench 11, and an irradiation unit 19 is fixedly installed in the inner cavity 112 of the workbench 11. The irradiation unit 19 is fixed on the bottom plate 113 of the workbench and is located below the LCD screen 191.

[0038] A support ring 114 is provided on the top plate 111 of the workbench. The material tank 17 is fixedly installed on the top of the support ring 114 and located above the LCD screen. The irradiation unit provides a forming beam to cure the photosensitive resin in the material tank 17. The irradiation unit 19 can be a digital light source processing (DLP) projection device or other types of projection devices (such as LCOS, LCD), but is not limited thereto.

[0039] The material trough 17 specifically includes a vertically extending trough wall 171 and a release film 174 sealed at the bottom of the trough wall. A material trough flange 175 is provided on the outer side of the bottom of the trough wall. Bolts pass through the material trough flange 175 and are screwed onto the support ring, thereby detachably fixing the material trough to the support ring. The printing platform can enter the material trough and print the model on its working surface.

[0040] In this embodiment, the printing platform 20 includes a body 21 and a model plate 23. A platform flange 22 is provided on the lower side of the body 21. The model plate 23 is detachably installed on the platform flange 22 by bolts. The lower surface of the model plate 23 is formed as a working surface 231.

[0041] In this embodiment, the connecting arm 14 has two horizontally spaced retaining arms 141 at the end away from the ball screw. The two retaining arms 141 extend away from the ball screw and are parallel to each other, forming a platform receiving cavity 142 between the two retaining arms. The platform receiving cavity has an opening away from the ball screw. Corresponding to each retaining arm 141, a slot 25 is provided on opposite sides of the body. The printing platform 20 is inserted into the platform receiving cavity 142, and each retaining arm 141 is inserted into the corresponding slot 25. The first bolt 16 passes through the retaining arm and is screwed into the first screw hole 251 located in the slot, so that the retaining arm is detachably fixed to the printing platform. To avoid shaking, each retaining arm is fixed to the printing platform by two first bolts.

[0042] An air duct is provided on the printing platform. In this embodiment, the air duct includes an upper air duct 211 disposed in the main body and a lower air duct 232 disposed in the model plate. The upper air duct 211 and the lower air duct 232 extend vertically and are coaxially arranged. The upper air duct 211 and the lower air duct 232 are connected vertically. The upper air duct 211 penetrates the upper end face of the main body upward, and the lower air duct 232 penetrates the lower end face of the model plate downward. That is, the upper air duct 211 and the lower air duct 232 together constitute the air duct. The air duct penetrates the upper and lower sides of the printing platform. The upper end of the air duct forms an air inlet, and the lower end of the air duct forms an air outlet.

[0043] Since both the upper air hole 211 and the lower air hole 232 extend vertically and are coaxially arranged, the air guide hole extends vertically.

[0044] The central stripping mechanism includes a vacuum device 41, an adsorber 45, and a swing device 50. In this embodiment, the vacuum device 41 is specifically a Roots vacuum pump, which is fixedly installed in the inner cavity 112 of the worktable.

[0045] The adsorber 45 includes a circular adsorption disk 451, which is horizontal and has an arc-shaped outer circumference. The adsorption disk has a hollow cavity 452. The center of the upper surface of the adsorption disk is recessed downward to form an adsorption cavity 453 with an arc-shaped bottom surface. Several adsorption holes 454 are provided on the upper wall of the adsorption disk. The several adsorption holes are arranged in the area where the adsorption cavity is located, and the adsorption holes connect the hollow cavity and the adsorption cavity.

[0046] The swing device 50 includes a swing motor 51, which is a servo motor. The swing motor is fixed to the lower surface of the top plate of the worktable, so that the swing motor is located in the inner cavity of the worktable. The output shaft 52 of the swing motor 51 extends upward from the top plate of the worktable. A connecting crossbar 43 is welded to one end of the vacuum pipe 44, and a positioning hole is provided at the end of the connecting crossbar away from the vacuum pipe. The connecting crossbar is sleeved on the output shaft 52 of the swing motor 51 through the positioning hole. A set screw 53 is screwed into the hole wall of the positioning hole, and the set screw 53 penetrates the hole wall and presses tightly against the output shaft of the swing motor 51, so that the vacuum pipe is fixed to the output shaft of the swing motor 51 through the connecting crossbar. A notch 115 is provided on the support ring, and the connecting crossbar 43 is freely passed through the notch and installed on the output shaft 52 of the swing motor 51.

[0047] To facilitate the rotation of the vacuum tube 44, the cross-section of the output shaft of the swing motor 51 is square, and the positioning hole is square to match the output shaft.

[0048] The other end of the vacuum tube 44 is bent upwards and welded to the bottom of the adsorption plate 451, and the vacuum tube is connected upwards to the hollow cavity 452 of the adsorption plate, so that the adsorber 45 is mounted on the swing device. The vacuum port of the Roots vacuum pump is connected to the vacuum tube 44 through the negative pressure tube 42, so that the adsorption hole is connected to the vacuum port of the vacuum device after passing through the hollow cavity of the adsorption plate, the vacuum tube and the negative pressure tube in sequence.

[0049] Driven by the oscillating device, the adsorber oscillates between the working position and the resting position. Please refer to [link / reference]. Figure 4 , Figure 4 In the diagram, the solid line indicates the adsorber in the working position, while the dashed line indicates the adsorber in the parking position.

[0050] Model 30 is bonded to the working surface 231 of the printing platform. A demolding hole 31 is formed within the model. The upper end of the demolding hole 31 is connected to the air outlet, and the demolding hole penetrates downward through at least one cured layer. For details regarding the demolding hole 31, please refer to the relevant content in Example 2 below.

[0051] When the adsorber is in the working position, the adsorber orifice is located directly below the lower port of the demolding orifice; when the adsorber is in the resting position, the adsorber is located outside the projection of the printing platform in the vertical direction. Figure 4 The area shown by the dashed line 1121 is the projection range of the printing platform in the vertical direction.

[0052] After the curing layer is completed through a release hole, the adsorber can be positioned in the working position and adsorb the release film facing the lower end of the release hole. When the transmission mechanism drives the printing platform to move upward, the release film can be peeled off from the curing layer from the inside to the outside along the lower edge of the release hole.

[0053] To prevent wear caused by contact between the adsorber and the release film from affecting the service life of the release film, a gap of 0.1-0.5 mm is maintained between the upper surface of the adsorber and the lower surface of the release film. Specifically, in this embodiment, the gap between the upper surface of the adsorber and the lower surface of the release film is 0.3 mm. It is understood that in other embodiments, the gap between the upper surface of the adsorber and the lower surface of the release film can also be 0.1 mm, 0.2 mm, 0.4 mm, or 0.5 mm, or other values ​​between 0.1-0.5 mm. For clarity, the distance between the upper surface of the adsorber and the lower surface of the release film is magnified beyond a suitable scale in the accompanying drawings.

[0054] Example 2

[0055] Please see Figures 6-8 This embodiment describes a 3D printing method using the 3D printer described in Embodiment 1. The 3D printing method includes the following steps:

[0056] (1) After the 3D model of the model to be printed is completed, calculate the cylindrical hole area with a set diameter. Please refer to [reference needed]. Figure 2 ,exist Figure 2 In the model 30 shown, model 30 is represented by a dashed line. The area enclosed by the double-dotted line 91 is the hole-forming area. For clarity, the double-dotted line 91 extends upwards to the model plate 23 and downwards to the bottom of model 30. Similarly, for clarity, no cross-sectional lines are provided on model 30. In this embodiment, the membrane removal holes are straight lines and extend vertically.

[0057] The diameter of the hole-forming area is set to 20mm, and the release hole is a circular hole with an inner diameter of 10mm, making the set diameter of the hole-forming area 10mm larger than the inner diameter of the release hole. The hole-forming area extends to an outer end face 35 of the model to be printed, and the extension direction of the hole-forming area is perpendicular to the outer end face, which can serve as the starting face for model printing. In this embodiment, the model to be printed consists of 1000 cured layers, and the hole-forming area extends downward from the starting face by 990 cured layers, i.e., N=1000, M=10, NM=990, N>M. The thickness of each cured layer is 0.1mm.

[0058] It is understandable that the inner diameter of the demolding hole can also be 5mm, 7mm, or 9mm. When the set diameter of the pore area is larger, the inner diameter of the demolding hole can also be 12mm, 15mm, or 20mm. Of course, depending on the size of the pore area, the inner diameter of the demolding hole can be flexibly selected between 5-20mm.

[0059] (2) Print the model to be printed with the outer end face as the starting face. During the printing process of the curing layer of the model, a demolding hole 31 is formed in the hole area. The demolding hole 31 is connected to the air guide hole upward and penetrates the lower end face of the curing layer located at the bottom side downward.

[0060] After each cured layer is printed, the oscillating device 50 is activated to move the suction unit from the resting position to the working position. The vacuum device 41 is activated to suction the release film onto the suction unit. Then, the transmission mechanism is activated to lift the printing platform upwards, causing the release film to peel outwards along the lower edge of the release hole, while simultaneously peeling inwards along the outer edge of the model, until the cured layer is completely separated from the release film. The vacuum device is then turned off, and the release film detaches from the suction unit. The oscillating device is activated again to move the suction unit from the working position to the resting position. Then, the printing platform is lowered so that the distance between the model and the release film is the thickness of one cured layer, and the printing of the next cured layer continues.

[0061] Please see Figure 7 Due to the adhesive force and the adsorption force generated by the vacuum, when the printing platform is lifted upward, it will drive the corresponding area of ​​the release film 174 upward, so that an outer peeling opening 902 is generated between the outer edge of the curing layer and the release film. At the same time, since the release film below the release hole is fixed by the adsorber, the release film can also generate an inner peeling opening 901 between the lower edge of the release hole and the curing layer, so that the release film peels outward along the edge of the release hole, allowing the release film to be peeled from both the inside and outside of the curing layer, forming a bidirectional peeling method.

[0062] Please see Figure 8 As the inner peeling port 901 and the outer peeling port 902 continue to extend and expand, they become interconnected, allowing the release film to completely peel off from the cured layer. Once the cured layer and the release film are completely separated, the vacuum device is turned off, the release film detaches from the adsorber, and the oscillating device is restarted to move the adsorber from the working position to the parking position.

[0063] Because the release film can be peeled off from both the inside and outside, the peeling efficiency is improved, and the lifting height of the printing platform during release film peeling is reduced, thereby improving printing efficiency.

[0064] Continue printing the cured layers until 990 cured layers have been printed, which is equivalent to printing NM cured layers. As printing progresses, the release holes lengthen as the model extends.

[0065] (3) Complete the printing of the last 10 curing layers, that is, complete the printing of the last M curing layers.

[0066] To maintain the integrity of the model's appearance, the M cured layers at the bottom layer together form a sealing layer 32. This sealing layer seals the lower end of the demolding hole to maintain the integrity of the model's appearance. In this embodiment, the sealing layer is composed of the 10 cured layers at the bottom layer, that is, M cured layers together constitute the sealing layer. Please refer to [link / reference] for details. Figure 2 In this embodiment, the thickness H of the sealing layer is 1 mm. It can be understood that, depending on different requirements, the thickness of the sealing layer can also be 2 mm, 3 mm, 4 mm or 5 mm, or other thicknesses between 1 and 5 mm.

[0067] When printing the last 10 cured layers, the release film is still peeled off from the cured layer in the traditional way, relying solely on the rise of the printing platform to complete the peeling of the release film from the cured layer.

[0068] After printing the model, remove the model from the printing platform, pour out the photosensitive resin remaining in the air vent through the orifice on the starting surface, and clean the air vent.

Claims

1. A 3D printer with a center pull-down peeling function, characterized in that, The device includes a worktable and a central peeling mechanism. A transmission mechanism is mounted on the worktable, which has a ball screw extending vertically and a connecting arm meshing with the ball screw. The free end of the connecting arm forms a working end, and a printing platform is detachably mounted on the working end. The lower surface of the printing platform forms a working surface. The connecting arm can drive the printing platform to reciprocate vertically. An air guide hole is opened on the printing platform, which extends through the upper and lower sides of the printing platform. The upper end of the air guide hole forms an air inlet, and the lower end forms an air outlet. The central stripping mechanism includes a vacuum device, an adsorber, and a swinging device. The vacuum device is fixedly installed in the inner cavity of the worktable. The adsorber has an adsorption hole that is connected to the vacuum port of the vacuum device. The swinging device is installed on the worktable, and the adsorber is installed on the swinging device. The swinging device can drive the adsorber to swing between the working position and the resting position. A material trough is arranged on the worktable, and the printing platform can enter the material trough and print the model on its working surface; The model is bonded to the printing platform, and a demolding hole is formed inside the model. The upper end of the demolding hole is connected to the air outlet, and the demolding hole penetrates downward through at least one cured layer. When the adsorber is in the working position, the adsorbing hole is located directly below the lower port of the demolding hole. When the adsorber is in the parking position, the adsorber is located outside the projection of the printing platform in the vertical direction. After the curing layer is completed through a release hole, the adsorber can be positioned in the working position and adsorb the release film facing the lower end of the release hole. When the transmission mechanism drives the printing platform to move upward, the release film can be peeled off from the curing layer from the inside to the outside along the lower edge of the release hole.

2. The 3D printer according to claim 1, characterized in that, The distance between the upper surface of the adsorber and the lower surface of the release film is 0.1-0.5 mm.

3. The 3D printer according to claim 2, characterized in that, The connecting arm has two horizontally spaced retaining arms at the end away from the ball screw. The two retaining arms extend away from the ball screw and are parallel to each other, forming a platform receiving cavity between the two retaining arms. The platform receiving cavity has an opening facing away from the ball screw. Corresponding to each retaining arm, a slot is provided on opposite sides of the printing platform. The printing platform is inserted into the platform receiving cavity, and each retaining arm is inserted into its corresponding slot. Each retaining arm is fixed to the printing platform by bolts.

4. The 3D printer according to claim 1, characterized in that, The oscillating device includes an oscillating motor, which is a servo motor. The oscillating motor is fixed in the inner cavity of the worktable, and the output shaft of the oscillating motor extends upward from the top plate of the worktable. The air inlet pipe of the adsorber is fixed on the output shaft of the oscillating motor.

5. The 3D printer according to claim 1, characterized in that, The adsorber includes a circular adsorption disk with a hollow cavity inside. The center of the upper surface of the adsorption disk is recessed downward to form an adsorption cavity with an arc-shaped bottom surface. The adsorption hole connects the hollow cavity and the adsorption cavity.

6. A 3D printing method, characterized in that, The 3D printing method, performed using any one of claims 1-5, comprises the following steps: (1) After the 3D model of the model to be printed is completed, a cylindrical hole area with a set diameter is calculated. The hole area can extend to at least one outer end face of the model to be printed, and the outer end face is used as the starting face when printing the model. The model to be printed consists of N curing layers, and the hole-forming area extends downward from the starting surface by NM curing layers, where N > M; (2) Print the model to be printed with the outer end face as the starting face. During the printing process of the curing layer of the model, a demolding hole is formed in the hole forming area. The demolding hole is connected to the air guide hole upward; the demolding hole penetrates the lower end face of the curing layer located at the bottom. After each cured layer is printed, the swing device is activated to move the suction unit from the resting position to the working position. The vacuum device is activated to adsorb the release film onto the suction unit. Then, the transmission mechanism is activated to lift the printing platform upward, causing the release film to peel outward along the lower edge of the release hole, while simultaneously peeling inward along the outer edge of the model, until the cured layer is completely separated from the release film. The vacuum device is then turned off, and the release film detaches from the suction unit. The swing device is activated again to move the suction unit from the working position to the resting position. Continue printing the cured layers until NM cured layers have been printed; (3) Complete the printing of the last M curing layers.

7. The 3D printing method according to claim 6, characterized in that, The exfoliation pores are straight and extend vertically.

8. The 3D printing method according to claim 6, characterized in that, The diameter of the pore formation area is set to be ≥10mm larger than the inner diameter of the demolding hole.

9. The 3D printing method according to claim 6, characterized in that, The inner diameter of the stripping hole is 5-20mm.

10. The 3D printing method according to claim 6, characterized in that, The total thickness of the M cured layers is 1-5mm, and the demolding holes do not penetrate the M cured layers.

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