A modeling platform component for an ultraviolet 3D printing device

Abstract

This invention is a divisional application with the application number 2024112032628. This application discloses a modeling platform component for an ultraviolet 3D printing device, which can be installed on a boom of a transmission mechanism. It includes a printing platform, a guiding mechanism, and a hollow shaft torque motor. The printing platform can be installed on the boom through a spherical joint bearing. The guiding mechanism includes a limiting component and a guiding member for installation on the boom. The outer ring of the rolling bearing of the limiting component is fixed on the printing platform, and the inner ring is connected with a second upper connecting rod. The second upper connecting rod passes upward through the guiding hole of the guiding member. The stator of the hollow shaft torque motor can be fixed on the boom, and a driving ring is fixedly installed at the lower end of the rotor. The upper surface of the printing platform is an inclined driving surface, and the driving ring presses against the driving surface. This application uses the inclined driving surface to swing the printing platform, creating an angle between the cured layer and the release film, which can accelerate the separation of the cured layer from the bottom of the material tank and improve the printing efficiency.

Description

[0001] This application is a divisional application. The filing date of the original application is August 30, 2024, the application number is 2024112032628, and the invention title is: An ultraviolet light 3D printing device and an ultraviolet light 3D printing method. Technical Field

[0002] The present invention relates to 3D printing technology, and specifically relates to a modeling platform component for an ultraviolet light 3D printing device. Background Art

[0003] 3D printing technology is a method of constructing an object by layer-by-layer printing. Among them, the light curing technology of ultraviolet light or visible light forms a surface by the sliced cross-sectional pattern of a three-dimensional model, and forms a single layer of curing by projecting a light beam onto a photosensitive resin printing material, and the cured layers are stacked layer by layer to form a three-dimensional model.

[0004] During the process of layer-by-layer printing of a three-dimensional model, after one layer is cured, the printing platform needs to be lifted to separate the completed printed layer from the bottom of the material tank. To reduce the adhesion force, a release film is usually provided at the bottom of the container. However, even after the release film is provided, the adhesion force between the cured layer and the release film is still relatively large. Therefore, in order to facilitate the separation between the cured layer and the release film, multiple airflows or liquids are usually introduced between the release film and the transparent plate, so that multiple protrusions are generated upward on the release film to facilitate the separation between the cured layer and the release film. However, this method requires evacuating the airflows or liquids completely by vacuum after separating the cured layer from the release film, so that the release film fits completely with the light-transmitting plate to ensure that the curing light can pass through the light-transmitting plate and the release film to cure the photosensitive resin. However, in the actual operation process of this technology, some gases or liquids will remain between the release film and the light-transmitting plate, forming air cavities or liquid cavities, which will cause certain consumption of the curing light and affect the curing of the photosensitive resin. Summary of the Invention

[0005] To solve the above problems, the present application proposes a modeling platform component for an ultraviolet light 3D printing device, which includes a printing platform, a guiding mechanism, and a hollow shaft torque motor; the transmission mechanism of the ultraviolet light 3D printing device has a suspension rod extending in the vertical direction, and the modeling platform component can be installed on the suspension rod. When the modeling platform component is installed on the suspension rod, the suspension rod can drive the modeling platform component to reciprocate in the vertical direction;

[0006] The printing platform can be installed at the lower end of the suspension rod. When the printing platform is installed at the lower end of the suspension rod, the lower surface of the printing platform forms a working surface;

[0007] The printing platform can be installed at the lower end of the hanging rod through a spherical joint bearing. When the printing platform is installed at the lower end of the hanging rod, the ball head of the spherical joint bearing is fixedly installed at the lower end of the hanging rod through a first upper connecting rod, and the socket of the spherical joint bearing is fixedly installed on the printing platform through a first lower connecting rod;

[0008] The guiding mechanism includes a guiding member and a limiting assembly. The guiding member is used to be installed on the hanging rod and located above the printing platform. At least three limiting assemblies are installed on the upper side of the printing platform. Each limiting assembly includes a rolling bearing. The outer ring of the rolling bearing is fixedly installed on the printing platform through a mounting rod, and the inner ring of the rolling bearing is connected with a second upper connecting rod. The second upper connecting rod slidably passes upward through a guiding hole on the guiding member, and a guiding hole is provided corresponding to each second upper connecting rod;

[0009] The hollow shaft torque motor includes a stator and a rotor rotatably sleeved outside the stator. The stator can be fixedly installed on the hanging rod. The central axis of the hollow shaft torque motor extends in the vertical direction, and the hollow shaft torque motor is coaxially arranged with the first upper connecting rod; the at least three limiting assemblies are evenly spaced around the central axis of the hollow shaft torque motor; the hollow shaft torque motor is a servo motor;

[0010] A driving ring is fixedly installed at the lower end of the rotor. The driving ring is cylindrical and coaxially arranged with the hollow shaft torque motor. The lower end of the driving ring forms a driving end; a driving surface is formed on the upper surface of the printing platform. The driving surface is inclined, and the driving end abuts against the driving surface; when the rotor drives the driving ring to rotate around the central axis of the hollow shaft torque motor, the driving ring can drive the printing platform to swing with the center of the ball head of the spherical joint bearing as the center point and the central axis of the hollow shaft torque motor as the center line; each second upper connecting rod can only swing along the radial direction of the hollow shaft torque motor;

[0011] The printing platform has a working position. When the printing platform is in the working position, the working surface of the printing platform is horizontally arranged, the first upper connecting rod and the first lower connecting rod are coaxially arranged, and the mounting rod of the limiting assembly extends in the vertical direction.

[0012] The transmission mechanism is specifically installed on the workbench of the ultraviolet 3D printing device. A material tank is installed on the workbench, and an ultraviolet light system is installed in the workbench. The ultraviolet light system includes a liquid crystal screen fixed on the top plate of the workbench. The material tank is located above the liquid crystal screen, and the ultraviolet light emitted by the ultraviolet light system can irradiate the liquid crystal screen.

[0013] After this application is installed on an ultraviolet 3D printing device, since the driving surface is inclined, when the rotor of the hollow shaft torque motor drives the driving ring to rotate, the printing platform can swing, and the working surface of the printing platform can swing in the order of horizontal - inclined - horizontal. As a result, the working surface of the printing platform can drive the cured layer to incline relative to the horizontal plane, causing an angle to appear between the cured layer and the release film. Along with the swing of the printing platform, this angle gradually expands, thus enabling the cured layer to quickly separate from the bottom of the material tank. And during the swing of the printing platform, the orientation of this angle will rotate synchronously around the central axis of the hollow shaft torque motor as the rotor rotates. Moreover, during the swing of the printing platform, this angle will gradually increase as the rotor rotates, reach the maximum value, and then gradually decrease until the working surface of the printing platform is horizontally set again. That is, this application can utilize the swing of the printing platform to improve the separation efficiency between the cured layer and the material tank, thereby improving the printing efficiency.

[0014] During the swing of the printing platform, the maximum value of the angle between the cured layer and the bottom of the material tank is twice the angle between the driving surface and the horizontal plane.

[0015] Since the hollow shaft torque motor used in this application is a servo motor, it can precisely control its rotation angle, enabling the rotor of the hollow shaft torque motor to return the working surface of the printing platform to the horizontal state after rotating one week, thereby making the lower surface of the cured layer return to the horizontal state to ensure the printing quality of the product model.

[0016] Since this application uses the driving ring to make the printing platform swing, when the cured layer peels off from one side of the release film and a notch appears, this notch will also extend along the circumferential direction of the cured layer and gradually expand as the driving ring rotates.

[0017] Furthermore, to make the driving ring form a stable pressure on the driving surface, the lower end surface of the driving end of the driving ring is an inclined surface, and the lower end surface of the driving end is parallel to the driving surface of the printing platform. This design can make the lower end surface of the driving end always fully press against the driving surface of the printing platform, preventing the printing platform from swinging uncontrollably.

[0018] Furthermore, to reduce the friction between the driving ring and the driving surface, a universal ball head is installed on the driving end of the driving ring, and the driving end presses against the driving surface through this universal ball head.

[0019] Further, to prevent the printing platform from displacing horizontally during the swinging process, the center of the ball of the spherical joint bearing lies within the driving surface. Although causing the printing platform to displace horizontally is beneficial for the peeling between the cured layer and the release film, it will also subject the unfinished model to a horizontal thrust, making it prone to bending or breaking. This design enables the printing platform to only swing without moving horizontally.

[0020] Specifically, when the printing platform is in the working position, the angle between the driving surface and the horizontal plane is 0.2 - 3°. The above angle can be selected according to the size of the cross-section of the product model. When the cross-section of the product model is larger, a smaller above angle can create a larger distance between the cured layer of the product model and the same side of the release film, thereby separating the cured layer from the release film.

[0021] Further, the guiding hole is a long hole extending along the radial direction of the hollow shaft torque motor. When the rotor drives the driving ring to rotate around the central axis of the hollow shaft torque motor, the second upper connecting rod will move radially with respect to the hollow shaft torque motor. After setting the guiding hole as a long hole extending along the radial direction of the hollow shaft torque motor, it can ensure that the second upper connecting rod moves smoothly along the radial direction of the hollow shaft torque motor within the guiding hole, ensuring the smooth swinging of the printing platform.

[0022] Further, to prevent the second upper connecting rod from tilting in the circumferential direction of the hollow shaft torque motor, the guiding hole is set to only allow the second upper connecting rod to move radially with respect to the hollow shaft torque motor and not allow the second upper connecting rod to move circumferentially with respect to the hollow shaft torque motor.

[0023] The steps of the ultraviolet 3D printing method using the ultraviolet 3D printing device equipped with any of the above modeling platform components are as follows:

[0024] (1) Place the printing platform in the working position, start the transmission mechanism, immerse the printing platform into the photosensitive resin in the material tank, and complete the printing of the first cured layer on the working surface of the printing platform;

[0025] (2) Lift the printing platform upward, then start the hollow shaft torque motor, rotate the rotor one week. Driven by the driving ring, the printing platform swings with the center of the ball of the spherical joint bearing as the center point and the central axis of the hollow shaft torque motor as the center line, separating the first cured layer from the release film and achieving a first set distance between the first cured layer and the release film, where the first set distance is greater than the thickness of one cured layer;

[0026] During the swinging process of the printing platform, the working surface forms an angle with respect to the horizontal plane. The orientation of this angle rotates around the central axis of the hollow shaft torque motor as the rotor rotates. And during the swinging process of the printing platform, this angle gradually increases as the rotor rotates, reaches the maximum value, and then gradually decreases until the working surface of the printing platform is horizontally set again;

[0027] (3) Lower the printing platform so that the distance between the first cured layer and the release film reaches the thickness of one cured layer, and then complete the printing of the second cured layer;

[0028] (4) Repeat steps (2) and (3) until the printing of the product model is completed.

[0029] In this UV 3D printing method, by using the inclined driving surface, when the rotor of the hollow shaft torque motor drives the driving ring to rotate, the printing platform can be swung, so that the working surface of the printing platform can be inclined with respect to the horizontal plane, thereby making the cured layer on the working surface inclined with respect to the horizontal plane, resulting in an angle between the cured layer and the release film. This angle causes the bonding surface between the release film and the cured layer to gradually separate from one side to the other side, overcoming the problem of the large bonding force between the cured layer and the release film. As the printing platform swings, this angle gradually expands, so that the cured layer and the release film are quickly separated. When this angle reaches the maximum, with the continuous swinging of the printing platform, the working surface of the printing platform gradually returns to the horizontal state.

[0030] Specifically, to avoid the downward moving end squeezing the product model and causing damage to the product model when the printing platform swings, in step (2), after lifting the printing platform upward for 0.5 - 2 seconds and before the distance between the first cured layer and the release film reaches the first set distance, start the hollow shaft torque motor. Or, in step (2), when the distance between the first cured layer and the release film reaches the first set distance, start the hollow shaft torque motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic structural diagram of an embodiment of the present invention, specifically the state diagram when the printing platform is in the working position.

[0032] Figure 2 is the state diagram when the release film and the cured layer are partially separated.

[0033] Figure 3 is the state diagram when the release film and the cured layer are completely separated.

[0034] Figure 4 is the structural diagram of the modeling platform assembly. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] Refer to Figures 1 - 4 , an ultraviolet 3D printing device, which includes a workbench 11. A transmission mechanism is installed on the workbench. The transmission mechanism adopts existing mature technologies. The transmission mechanism includes a vertical rod 12 fixed on the workbench 11 and a ball screw 13 rotatably installed on one side of the vertical rod. The ball screw 13 extends in the vertical direction, and one end of a connecting arm 14 is engaged with the ball screw through a threaded hole. The connecting arm 14 extends in the horizontal direction. A hanging rod 15 is fixedly installed at the end of the connecting arm 14 away from the ball screw. The hanging rod extends in the vertical direction and is cylindrical.

[0036] A modeling platform assembly 700 is installed on the hanging rod 15. A driving motor is installed at the lower end of the ball screw. The driving motor is fixedly installed on the vertical rod. The driving motor can drive the ball screw to rotate, so that the connecting arm can drive the modeling platform assembly to reciprocate in the vertical direction. And an ultraviolet light system is installed in the workbench. The ultraviolet light system includes a liquid crystal screen fixed on the top plate of the workbench. The ultraviolet light system is not shown in the drawings. The ultraviolet light system adopts existing mature technologies and will not be elaborated here. The lower surface of the printing platform forms a working surface.

[0037] The printing platform 31 is installed at the lower end of the hanging rod. The lower surface of the printing platform 31 forms a working surface 34. Specifically, the printing platform 31 is movably installed at the lower end of the hanging rod 15 through a spherical joint bearing 40. The ball head 43 of the spherical joint bearing 40 is fixedly installed at the lower end of the hanging rod through a first upper connecting rod 42. The socket 44 of the spherical joint bearing is fixedly installed on the printing platform through a first lower connecting rod 41. Both the first lower connecting rod 41 and the first upper connecting rod 42 are screwed onto the printing platform and the hanging rod respectively by means of threads.

[0038] The guiding mechanism includes a guiding member 61 and a limiting assembly 50. The guiding member 61 is installed on the hanging rod and is located above the printing platform 31. Three limiting assemblies 50 are installed on the upper side of the printing platform. Each limiting assembly 50 includes a rolling bearing 53. The outer ring of the rolling bearing is fixedly installed on the printing platform through a mounting rod 51. A rotating shaft 54 is fixedly installed on the inner ring of the rolling bearing. And a second upper connecting rod 52 is fixedly installed on the rotating shaft. The second upper connecting rod 52 slides upward through a guiding hole 62 on the guiding member. A guiding hole is provided corresponding to each second upper connecting rod. A guiding hole 62 is provided on the guiding member 61 corresponding to each second upper connecting rod 52. The mounting rod 51 is screwed onto the printing platform by means of threads. Each second upper connecting rod can only swing radially along the following hollow shaft torque motor 70. In this embodiment, the rolling bearing 53 specifically adopts a double row angular contact ball bearing.

[0039] The hollow shaft torque motor 70 is installed on the suspension rod 15. The hollow shaft torque motor 70 includes a stator 75 and a rotor 71 rotatably sleeved outside the stator 75. A hollow shaft 76 is fixedly lined inside the stator. The top of the hollow shaft 76 is fixedly connected to the flange 151 on the suspension rod 15 by bolts. The flange 151 is formed by protruding radially outward from the outer peripheral surface of the suspension rod. To ensure the connection stability between the hollow shaft and the suspension rod, a key 77 is provided between the hollow shaft and the suspension rod, so that the stator is fixed on the suspension rod through the hollow shaft.

[0040] An upper end cover 72 and a lower end cover 73 are respectively installed at the upper and lower ends of the rotor 71. The upper end cover 72 is bolted to the upper flange 711 at the upper end of the rotor 71, and the lower end cover 73 is bolted to the lower flange 712 at the lower end of the rotor 71. Both the upper flange 711 and the lower flange 712 are integrally formed on the rotor 71.

[0041] In this embodiment, an upper connecting flange 16 is provided on the outer peripheral surface of the hollow shaft 76. The upper end cover has an inwardly protruding upper abutting flange 721. The lower surface of the upper abutting flange 721 is a stepped surface facing downward. The upper abutting flange 721 presses against the upper side of the outer ring of the angular contact bearing 18 through its lower surface, and the upper connecting flange 16 presses against the lower side of the inner ring of the angular contact bearing, so that the upper end cover is rotatably connected to the hollow shaft 76 through the angular contact bearing.

[0042] A lower stepped portion 17 is provided at the lower end of the hollow shaft 76. The lower stepped portion has a stepped surface facing downward. The lower stepped portion 17 is formed by radially inwardly recessing from the outer peripheral surface of the hollow shaft 76; the lower end cover has an inwardly protruding lower abutting flange 731. The upper surface of the lower abutting flange 731 is a stepped surface facing upward. The lower abutting flange 731 abuts against the lower side of the outer ring of the angular contact bearing 19 through its upper surface, and the lower stepped portion 17 presses against the lower side of the inner ring of the angular contact bearing, so that the lower end cover is rotatably connected to the hollow shaft 76 through the angular contact bearing. A winding 74 is provided inside the stator. The structure of the hollow shaft torque motor can be completed by using existing mature technologies and will not be elaborated here.

[0043] The central axis of the hollow shaft torque motor extends in the vertical direction. The hollow shaft torque motor is coaxially arranged with the first upper connecting rod, and the hollow shaft torque motor is a servo motor. Three limiting components 50 are evenly spaced around the central axis of the hollow shaft torque motor 70.

[0044] A driving ring 78 is fixedly installed on the lower side of the lower end cover 73. The driving ring 78 is in a cylindrical shape and is coaxially arranged with the hollow shaft torque motor. An integrally formed flanging flange 781 is provided at the upper end of the driving ring 78. The flanging flange 781 is fixedly connected to the lower side of the lower end cover 73 by bolts, thereby fixing the driving ring on the lower end cover.

[0045] On the upper surface of the printing platform 31, a driving platform 32 is formed, which protrudes upward from the upper surface of the printing platform 31. The upper surface of the driving platform 32 is formed as a driving surface 33, and the driving surface 33 is inclined. The driving end is pressed against this driving surface, and the center 45 of the ball head 43 of the spherical joint bearing is located within the driving surface. For the sake of clarity, in Figure 3 Figure, the center 45 of the ball head 43 is represented by a small circle.

[0046] In this embodiment, the lower end surface of the driving end of the driving ring is an inclined surface, and the lower end surface of the driving end is parallel to the driving surface of the printing platform. It can be understood that in order to reduce the friction between the driving end and the driving surface, in another embodiment, a universal ball head 79 can also be installed on the lower end surface of the driving end, and the driving end is pressed against the driving surface 33 through the universal ball head 79.

[0047] In this embodiment, when the printing platform is in the working position, the included angle α between the driving surface and the horizontal plane is 2°. It can be understood that in other embodiments, the included angle α can also be 0.2°, 0.5°, 0.8°, 1.2°, 1.5°, 2° or 3°.

[0048] When the mover drives the driving ring to rotate around the central axis of the hollow shaft torque motor, the driving ring can drive the printing platform to swing with the center 45 of the ball head 43 of the spherical joint bearing as the center point and with the central axis of the hollow shaft torque motor as the center line.

[0049] When the mover drives the driving ring to rotate around the central axis of the hollow shaft torque motor, the second upper connecting rod will move in the radial direction of the hollow shaft torque motor. To ensure that the second upper connecting rod moves smoothly in the guiding hole 62 in the radial direction of the hollow shaft torque motor, in this embodiment, the guiding hole is a long hole extending in the radial direction of the hollow shaft torque motor, and the guiding hole is set to only enable the second upper connecting rod to move in the radial direction of the hollow shaft torque motor and not enable the second upper connecting rod to move circumferentially relative to the hollow shaft torque motor.

[0050] The printing platform has a working position. When the printing platform is in the working position, the working surface of the printing platform is horizontally arranged, the first upper connecting rod and the first lower connecting rod are coaxially arranged, and the mounting rod of the limiting component extends in the vertical direction.

[0051] Please refer to Figure 4 Figure. For the sake of easy description, when the printing platform is in the working position, in the direction from high to low of the driving surface 33, the two opposite ends of the printing platform are respectively called the first side portion 311 and the second side portion 312. In Figure 4Among them, the direction pointed by arrow X indicates the direction from high to low of the driving surface 33. The first side portion 311 is located at the lower end of the driving surface 33, and the second side portion 312 is located at the upper end of the driving surface 33.

[0052] When the hollow shaft torque motor drives the printing platform to swing, the first side portion 311 will first move upward until it reaches the highest point, and then move downward until the working surface returns to the horizontal state; at the same time, the second side portion 312 will first move downward until it reaches the lowest point, and then move upward until the working surface returns to the horizontal state; during this process, taking the connection line between the first side portion and the second side portion as the dividing line, the area of the printing platform on one side of the dividing line will first move downward synchronously, and then move upward until the working surface returns to the horizontal state, and the area of the printing platform on the other side of the dividing line will first move upward synchronously, and then move downward until the working surface returns to the horizontal state. Figure 1 In [description], the printing platform is in the working position. Figure 2 In [description], the first side portion 311 moves upward to the highest point, and the second side portion 312 moves downward to the lowest point. Both the highest point and the lowest point are relative to the center of the ball head of the ball head joint bearing. At this time, the working surface of the printing platform is in the maximum inclined state.

[0053] A material tank 21 is installed on the workbench, and a release film 22 is installed at the bottom of the material tank. The material tank is located above the liquid crystal screen, and the ultraviolet light emitted by the ultraviolet light system can irradiate the liquid crystal screen.

[0054] Viewed along the vertical direction, in this embodiment, the rotor of the hollow shaft torque motor rotates counterclockwise. When a gap 90 appears between the side of the cured layer facing the first side portion and the release film, the gap will also gradually extend counterclockwise synchronously with the rotation of the rotor, and the distance between the side of the cured layer facing the first side portion and the release film will gradually increase.

[0055] The following describes the ultraviolet light 3D printing method in the present application. This ultraviolet light 3D printing method is carried out by using the above-mentioned ultraviolet light 3D printing device. The ultraviolet light 3D printing method includes the following steps:

[0056] (1) Place the printing platform in the working position, start the transmission mechanism, immerse the printing platform into the photosensitive resin in the material tank, and complete the printing of the first cured layer 80 on the working surface of the printing platform.

[0057] (2) Lift the printing platform upward, then start the hollow shaft torque motor to rotate the mover for one week. Driven by the driving ring, the printing platform swings with the center of the ball head of the spherical joint bearing as the center point and the central axis of the hollow shaft torque motor as the center line, so that the first cured layer is separated from the release film, and a first set distance is achieved between the first cured layer and the release film. This first set distance is greater than the thickness of one cured layer.

[0058] During the swinging process of the printing platform, the working surface will form an angle with respect to the horizontal plane. The orientation of this angle will rotate around the central axis of the hollow shaft torque motor as the mover rotates. And during the swinging process of the printing platform, this angle will gradually increase as the mover rotates and reach the maximum value, then gradually decrease until the working surface of the printing platform is horizontally set again.

[0059] While the working surface forms an angle with the horizontal plane, a V-shaped notch 90 will be generated between the first cured layer and the release film. The orientation of this notch will rotate synchronously with the above-mentioned angle and gradually increase until the first cured layer is completely separated from the release film. For details, please refer to Figure 2 and Figure 3 .

[0060] (3) Lower the printing platform to make the distance between the first cured layer and the release film reach the thickness of one cured layer, and then complete the printing of the second cured layer;

[0061] (4) Repeat steps (2) and (3) until the printing of the product model is completed.

[0062] In this embodiment, when the printing platform is lifted upward for 1 second and then the hollow shaft torque motor is started, at this time, the distance between the first cured layer and the release film has not reached the first set distance. Due to the swinging of the printing platform, the working surface 34 of the printing platform is inclined with respect to the horizontal plane, so that a notch 90 can be generated between the first cured layer and the release film on the side facing the first side. As the printing platform continues to rise and the printing platform continues to swing, the orientation of this notch 90 rotates synchronously around the central axis of the hollow shaft torque motor as the mover rotates and gradually expands until the first cured layer is continuously peeled off from the release film until it is completely peeled off. When the hollow shaft torque motor rotates one week, the working surface returns to the horizontal state again.

[0063] Since the angle α between the driving surface and the horizontal plane is 1°, during the swinging process of the printing platform, the maximum angle between the working surface and the horizontal plane will reach 2°.

[0064] It can be understood that in another embodiment, in step (2), when the first set distance is reached between the first cured layer and the release film, the hollow shaft torque motor can be started again to make the first cured layer inclined relative to the horizontal plane and completely peel the first cured layer from the release film.

Claims

1. A modeling platform assembly for an ultraviolet 3D printing device, characterized in that: The invention comprises a printing platform, a guide mechanism and a hollow shaft torque motor; the transmission mechanism of the ultraviolet 3D printing device has a suspension rod extending in a vertical direction, the modeling platform assembly can be installed on the suspension rod, and when the modeling platform assembly is installed on the suspension rod, the suspension rod can drive the modeling platform assembly to reciprocate in the vertical direction; The printing platform can be installed at the lower end of the suspension rod. When the printing platform is installed at the lower end of the suspension rod, the lower surface of the printing platform forms a working surface. The printing platform can be installed on the lower end of the suspension rod via a ball joint bearing. When the printing platform is installed on the lower end of the suspension rod, the ball head of the ball joint bearing is fixedly installed on the lower end of the suspension rod via the first upper connecting rod, and the ball socket of the ball joint bearing is fixedly installed on the printing platform via the first lower connecting rod; The guide mechanism includes a guide member and a limit assembly, the guide member is used to be installed on the suspension rod and is located above the printing platform, at least three limit assemblies are installed on the upper side of the printing platform, each limit assembly includes a rolling bearing, the outer ring of the rolling bearing is fixedly installed on the printing platform via a mounting rod, the inner ring of the rolling bearing is connected to a second upper connecting rod, the second upper connecting rod slides upward through the guide hole on the guide member, and a guide hole is provided corresponding to each second upper connecting rod; The hollow shaft torque motor comprises a stator and a mover rotatably mounted on the outside of the stator, the stator can be fixedly mounted on the suspension rod, the central axis of the hollow shaft torque motor extends in the vertical direction, and the hollow shaft torque motor is coaxially arranged with the first upper connecting rod; the at least three limit assemblies are evenly spaced and arranged around the central axis of the hollow shaft torque motor; the hollow shaft torque motor is a servo motor; A driving ring is fixedly installed at the lower end of the mover, the driving ring is cylindrical and is coaxially arranged with the hollow shaft torque motor, and the lower end of the driving ring forms a driving end; a driving surface is formed on the upper surface of the printing platform, the driving surface is inclined, and the driving end is pressed against the driving surface; when the mover drives the drive to rotate around the central axis of the hollow shaft torque motor, the driving ring can drive the printing platform to swing with the ball center of the ball joint bearing as the center point and the central axis of the hollow shaft torque motor as the center line; each second upper connecting rod can only swing along the radial direction of the hollow shaft torque motor; The printing platform has a working position. When the printing platform is located at the working position, the working surface of the printing platform is horizontally arranged, the first upper connecting rod and the first lower connecting rod are coaxially arranged, and the mounting rod of the limiting assembly extends in the vertical direction.

2. The modeling platform assembly according to claim 1, characterized in that: The lower end surface of the driving end of the driving ring is an inclined surface, and the lower end surface of the driving end is parallel to the driving surface of the printing platform.

3. The modeling platform assembly according to claim 1, characterized in that: A universal ball head is installed on the driving end of the driving ring, and the driving end is pressed against the driving surface through the universal ball head.

4. The modeling platform assembly according to claim 1, characterized in that: The center of the ball head of the ball joint bearing is located in the driving surface.

5. The modeling platform assembly according to claim 1, characterized in that: When the printing platform is in the working position, the angle between the driving surface and the horizontal plane is 0.2-3°.

6. The modeling platform assembly according to claim 1, characterized in that: The guide hole is a long hole extending in the radial direction of the hollow shaft torque motor.

7. The modeling platform assembly according to claim 1, characterized in that: The guide hole is configured to enable the second upper connecting rod to move only in the radial direction of the hollow shaft torque motor and to prevent the second upper connecting rod from moving in the circumferential direction relative to the hollow shaft torque motor.

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