Photocuring three-dimensional printing device and printing method

Abstract

An outer ring of a slewing bearing of the photocuring three-dimensional printing device is fixed to a workbench, a supporting cylinder is fixed to an inner ring of the slewing bearing, a material groove is formed in the top end face of the supporting cylinder, one side of the material groove is hinged to the supporting cylinder through a hinge shaft, and the material groove can rotate around the hinge shaft; when the printing platform carries the model to move upwards, the end, away from the hinge shaft, of the trough can be driven to move upwards, and the trough inclines. A driving wheel is arranged on a ball screw of the transmission device, and a driven wheel connected with the driving wheel is arranged on the inner ring, so that the ball screw can drive the inner ring to rotate and drive the supporting barrel and the trough to rotate synchronously. The invention further discloses a photocuring three-dimensional printing method. The servo motor for driving the ball screw to rotate is also used as the motor for rotating the trough, so that the control system is simplified. And when the model moves upwards, an included angle is formed between the curing layer and the horizontal plane, so that a gap is formed between the curing layer and the release film until the curing layer is completely separated from the release film.

Description

Technical Field

[0001] This invention relates to a photopolymerization 3D printing apparatus and printing method. Background Technology

[0002] 3D printing technology, which constructs objects layer by layer, involves lifting a printing platform after a cured layer is formed during the printing process to detach the cured layer from the bottom of the material tank after each layer is printed. To reduce adhesion, a release liner is usually placed at the bottom of the container. However, even with the release liner, the adhesion between the cured layer and the release liner remains relatively strong. Therefore, various release liner peeling techniques have been developed to facilitate the peeling of the cured layer from the release liner. One of these techniques is the material tank tilting technique. After a cured layer is formed, one end of the material tank is tilted downwards while the printing platform is lifted. This allows one side of the cured layer to peel off from the release liner first, creating a larger peeling angle and thus increasing the peeling speed. The material tank tilting technique can effectively accelerate the peeling speed of the cured layer from the release liner, thereby improving the efficiency of 3D printing.

[0003] To tilt the trough, a separate motor is needed to drive it, which complicates the equipment's control system. Therefore, further optimization of the trough tilting technology remains of practical significance. Summary of the Invention

[0004] To address the aforementioned issues, this application first proposes a photopolymerization 3D printing device, which includes a worktable and a forming mechanism. The forming mechanism includes a transmission device and a slewing bearing. The transmission device includes a vertical rod fixed to the worktable, a ball screw rotatably mounted on one side of the vertical rod, and a servo motor mounted on the worktable for driving the ball screw to rotate.

[0005] The slewing bearing includes an outer ring and an inner ring joined together by ball bearings. The central axis of the slewing bearing extends vertically. The outer ring is fixed to the worktable, and a support cylinder is fixed to the inner ring. A material trough is installed on the top surface of the support cylinder. One side of the material trough is hinged to the support cylinder via a hinge shaft. The central axis of the hinge shaft extends horizontally, and the material trough can rotate around the hinge shaft. The printing platform is mounted on the ball screw via ball nuts. When the printing platform carries the model upward, it can drive the end of the material trough away from the hinge shaft to move upward, causing the material trough to tilt.

[0006] The ball screw has a driving wheel and an inner ring has a driven wheel. The driving wheel is connected to the driven wheel, so that the ball screw can drive the inner ring to rotate and drive the support cylinder and the material trough to rotate synchronously.

[0007] An ultraviolet (UV) light system is fixedly installed inside the workbench. This system includes an LCD screen and a UV light source. The LCD screen is located directly below the material tank, and the UV light emitted by the UV light source illuminates the LCD screen. Since the material tank rotates during operation, the LCD screen does not contact the material tank to avoid wear and tear. Furthermore, in this application, both the LCD screen and the UV light source are fixedly installed inside the workbench.

[0008] In the photopolymerization 3D printing apparatus of this application, during printing, when the printing platform moves the model upward, the lower end face of the cured layer forms an angle with the horizontal plane, creating a V-shaped gap between the cured layer and the release film, which gradually widens until the cured layer and the release film completely separate. Because the ball screw rotates, it drives the support cylinder and the material trough to rotate synchronously, causing the angle between the cured layer and the horizontal plane to rotate synchronously as well, which further improves the release film peeling speed.

[0009] As printing progresses, the height of the printing platform gradually increases. Therefore, after each cured layer is printed, the support cylinder does not return to its original position but rotates by an angle, simultaneously rotating the material tray by an angle. This causes the printing area of ​​the release film to rotate as well, avoiding continuous printing in the same area of ​​the release film. This maximizes the use of the release film and extends its service life.

[0010] This application eliminates the dedicated motor for tilting the trough in the prior art. Instead, it utilizes a servo motor that drives the ball screw to rotate as the motor for rotating the trough, and makes corresponding improvements to the equipment. Since the dedicated motor for tilting the trough is eliminated, the corresponding control system can be eliminated, thereby simplifying the control system.

[0011] Furthermore, to prevent the material tank from tilting too much under the influence of the model, causing the photosensitive resin inside the tank to overflow, a limiting mechanism is installed on the support cylinder. This limiting mechanism is used to limit the tilt angle of the material tank.

[0012] Specifically, the limiting mechanism and the hinge shaft are located on opposite sides of the trough. The limiting mechanism includes a limiting member, one end of which is fixed to the support cylinder, and the other end of which is a limiting end located above the trough wall. When the end of the trough away from the hinge shaft moves upward, it can abut against the limiting end. This design ensures that the side of the trough away from the hinge shaft is in force balance when pressing against the limiting end. However, when the limiting member deviates from the above position, when the side of the trough away from the hinge shaft presses against the limiting end, an upward pulling force will be generated on the opposite side of the limiting member. This tends to cause the trough to deflect, easily generating deflection force on the hinge shaft and related accessories. Although it will not damage the trough structure, it will cause uneven wear on the hinge shaft, affecting its service life.

[0013] Furthermore, to prevent the release film from rapidly rotating downwards after detaching from the mold, causing violent shaking of the photosensitive resin inside the mold and even overflowing the mold, the limiting mechanism also includes a viscous damper. The piston rod and cylinder of the viscous damper are respectively hinged to the mold wall and the rotating cylinder. When the mold rotates upwards, it can drive the piston rod of the viscous damper to extend. When the mold and the release film of the mold are completely separated from the mold, under the action of gravity, the end of the mold away from the hinge axis moves downwards and presses against the rotating cylinder, while the piston rod of the viscous damper retracts.

[0014] Viscous dampers are used to limit the downward rotation speed of the feed trough, preventing it from rotating too fast and reducing the swaying amplitude of the photosensitive resin inside the trough.

[0015] Furthermore, the central axis of the material tank is spaced apart from the central axis of the printing platform. Preferably, this distance is 5-15 mm. This design allows relative movement between the bonding areas of the cured layer and the release film when the material tank rotates, facilitating smooth peeling. However, when the central axis of the printing platform coincides with the central axis of the material tank, the area of ​​the release film located on the central axis will not move relative to the cured layer when the material tank rotates. Instead, it will vortex around the central axis of the release film, accelerating its failure.

[0016] Specifically, to avoid excessive tilt angle of the material trough, the depth of the trough needs to be excessively increased. When the trough is tilted, the maximum angle between the trough and the horizontal plane is 4-8°. When the model has an irregular shape, the different shapes of each cured layer during printing result in different bonding areas between the cured layer and the release film, leading to different adhesive forces. Therefore, the tilt angle of the trough will vary during the peeling process of each cured layer and the release film. When the bonding area between the cured layer and the release film is small, the model and the release film may have already peeled off before the tilt angle of the trough reaches its maximum value. Conversely, when the bonding area between the cured layer and the release film is large, the tilt angle of the trough must reach its maximum value before the model and the release film can be peeled off. This application only limits the maximum tilt angle of the trough. In actual operation, the tilt angle of the trough can be freely set within the maximum tilt range during the peeling process of each cured layer and the release film, without deliberate restriction.

[0017] Furthermore, a set of transition gears is installed on the worktable. This gear set includes a first transition gear and a second transition gear arranged coaxially. The driving gear is connected to the first transition gear, and the second transition gear is connected to the driven gear. Coaxial arrangement means that both the first and second transition gears are fixedly mounted on the same shaft, enabling them to rotate at the same angular velocity under the drive of that shaft. Since the usable space around the ball screw is limited, it is not advisable to install a driving gear with an excessively large outer diameter. However, a driving gear with a smaller outer diameter results in a lower rotational speed for the support cylinder when driving it. By utilizing the first and second transition gears in the transition gear set, the rotational speed of the support cylinder can be effectively increased to achieve the desired speed.

[0018] Specifically, both the driving pulley and the first transition pulley are synchronous belt pulleys, with the synchronous belt wrapped around them. The second transition pulley and the driven pulley are both external gears, with the second transition pulley meshing with the driven pulley. Using synchronous belt pulleys effectively reduces the impact force on the driving pulley and minimizes its wear, preventing the replacement of the ball screw due to wear. When adjusting the rotational speed of the feed trough, this can be achieved by replacing the first transition pulley with a different outer diameter and the corresponding synchronous belt. If a corresponding synchronous belt is unavailable, a corresponding tensioner is required to ensure that the corresponding synchronous belt can use first transition pulleys with different outer diameters. The tensioner setting can be done according to existing technology and will not be specifically described in this application.

[0019] Secondly, this application also proposes a photopolymerization 3D printing method, which uses the photopolymerization 3D printing apparatus described in any of the above claims, and the printing method includes the following steps:

[0020] (1) Keep the material tank in a horizontal position, start the transmission device, immerse the printing platform into the photosensitive resin in the material tank, and complete the printing of the first curing layer on the printing platform;

[0021] (2) The servo motor rotates forward, driving the ball screw to rotate, causing the printing platform to move upward, and at the same time driving the material tank to rotate; when the printing platform moves upward, it drives the material tank to rotate around the hinge shaft, causing the end of the material tank away from the hinge shaft to move upward, causing the material tank to tilt, so that the first cured layer is completely peeled off from the release film of the material tank.

[0022] (3) The material tank rotates downward and returns to a horizontal state; simultaneously, the servo motor reverses and the printing platform is lowered so that the distance between the first curing layer and the release film reaches the thickness of one curing layer, thus completing the printing of the second curing layer;

[0023] (4) Repeat steps (2) and (3) until the model is printed.

[0024] As the printing platform moves the model upwards, the lower end of the cured layer forms an angle with the horizontal plane, creating a V-shaped gap between the cured layer and the release film. This gap gradually widens until the cured layer completely separates from the release film. Because the material tank tilts and rotates synchronously with the support cylinder, the angle between the cured layer and the horizontal plane also rotates synchronously, further improving the release film peeling speed.

[0025] As printing progresses, the height of the printing platform gradually increases. After each cured layer is printed, the support cylinder does not return to its original position but rotates by an angle, simultaneously rotating the material tray by an angle. This causes the printing area of ​​the release film to rotate as well, preventing continuous printing in the same area of ​​the release film. This maximizes the use of the release film and extends its service life.

[0026] This application eliminates the dedicated motor for tilting the trough in the prior art, allowing the servo motor that drives the ball screw to rotate to also function as the motor for rotating the trough, and makes corresponding improvements to the equipment. Since the dedicated motor for tilting the trough is eliminated, the corresponding control system can be eliminated, thereby simplifying the control system.

[0027] Specifically, during the peeling process of each cured layer from the release film, the material tank rotates 0.25-1 revolutions. If the material tank rotates too few times, the peeling advantage of the release film during rotation cannot be demonstrated. When the material tank rotates to 1 revolution, the peeling speed of the release film has reached its maximum, and there is no further benefit from excessive rotation of the material tank. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of an embodiment of the present invention.

[0029] Figure 2 yes Figure 1 A view from the center AA direction.

[0030] Figure 3 yes Figure 1 Enlarged view of section B.

[0031] Figure 4 yes Figure 1 Enlarged view of section C. Detailed Implementation

[0032] The following is a further detailed explanation of the photopolymer 3D printing device; please refer to [link / reference]. Figures 1-4 The photopolymer 3D printing apparatus includes a worktable 10 and a forming mechanism. The worktable 10 includes a rectangular cylindrical wall 11 extending vertically, a base plate 12 installed at the bottom of the wall, and a top plate 13 installed at the top of the wall.

[0033] The forming mechanism includes a transmission device 20 and a slewing bearing 60. The transmission device 20 includes a vertical rod 27 fixed on the worktable, a ball screw 22 rotatably mounted on one side of the vertical rod, and a servo motor 21 mounted on the worktable for driving the ball screw to rotate. Both the vertical rod and the ball screw extend in a vertical direction. The output shaft of the servo motor is fixedly connected to the ball screw. The connection of the vertical rod, the ball screw, and the servo motor all adopt existing mature technologies, which will not be described in detail here.

[0034] One end of the connecting arm 16 is engaged with a ball screw via a lead screw nut. The connecting arm 16 extends horizontally, and a printing platform 17 is fixedly installed at the end of the connecting arm 16 away from the ball screw, such that the printing platform is mounted on the ball screw via a ball nut. Specifically, in this embodiment, the printing platform is circular.

[0035] The slewing bearing 60 includes an outer ring 62 and an inner ring 61 joined together by balls 63. The outer ring 62 is fixed to the top plate of the worktable by locking bolts 64, and the central axis of the slewing bearing 60 extends vertically. Specifically, in this embodiment, to reduce the impact of the slewing bearing on the printing operation, a stepped hole 19 is formed in the top plate. The stepped hole 19 is wider at the top and narrower at the bottom, giving it an upward-facing stepped surface 191. The outer ring 62 is fixed to this stepped surface 191. The inner ring extends downward out of the stepped hole, and a driven wheel 66 is provided on the outer circumferential surface of the lower part of the inner ring. In this embodiment, the driven wheel is integrally formed on the inner ring. It can be understood that in other embodiments, the driven wheel can also be provided separately, or an external gear ring can be used.

[0036] The support cylinder 41 is inserted into the inner cavity of the inner ring. To facilitate fixing the support cylinder, a support ring 42 is welded on the outer wall of the support cylinder. The support ring is supported on the upper end face of the inner ring and fixed to the inner ring with bolts. A first metal key 43 is also installed between the support cylinder and the inner ring.

[0037] The material tank 30 is installed on the top surface of the support cylinder 41. The material tank 30 includes an annular tank wall 31, a light-transmitting glass plate 33 and a release film 32 installed at the bottom of the tank wall. The release film is attached to the upper surface of the light-transmitting glass plate 33, and the space between the release film and the tank wall forms a cavity for holding photosensitive resin.

[0038] A hinge lug 34 is integrally formed on the outer wall of one side of the groove wall. The hinge lug is located at the lower part of the groove wall. The upper end of the support cylinder extends upward from the inner ring. A protrusion 45 is welded to the top of the outer wall of the support cylinder. Two spaced vertical plates 46 are welded to the upper surface of the protrusion. The hinge lug is freely inserted between the two vertical plates. The hinge shaft 35 passes through the vertical plates and the hinge lug, and then hinges one end of the material groove to the support cylinder. The central axis of the hinge shaft extends horizontally, and the material groove can rotate around the hinge shaft. When the printing platform moves upward with the model, it can drive the end of the material groove away from the hinge shaft to move upward, causing the material groove to tilt.

[0039] A limiting mechanism 80 is installed on the support cylinder to limit the tilt angle of the material trough. In this embodiment, the limiting mechanism 80 and the hinge shaft 35 are located on opposite sides of the material trough. The limiting mechanism 80 includes a limiting member 81 and a viscous damper 83. The limiting member 81 is generally L-shaped and includes a vertically extending column 811 and a horizontal plate 812 connected to the top of the column. The end of the horizontal plate 812 away from the column is formed as a limiting end 813. A support plate 47 is horizontally installed on the outer wall of the top of the support cylinder, located on the opposite side of the protrusion 45. The lower end of the column 811 has a screw that passes downward through the support plate 47 and is screwed with a fastening nut 815 to fix the limiting member to the support plate and position the limiting end above the trough wall.

[0040] A pressure plate 36 is welded to the outer wall at the top of the tank wall. The pressure plate 36 is located on the opposite side of the hinge ear 34. The piston rod 832 and cylinder 831 of the viscous damper 83 are respectively hinged to the pressure plate 36 and the support plate 47, thereby hinged the piston rod and cylinder of the viscous damper to the tank wall and the support cylinder respectively. When the printing platform moves the model upward, the piston rod of the viscous damper can be extended. When the model and the release film of the material tank are completely peeled off, under the action of gravity, the end of the material tank away from the hinge axis moves downward, the material tank rotates downward and presses against the rotating cylinder, so that the material tank returns to the horizontal state and the piston rod of the viscous damper retracts. The viscous damper allows the material tank to rotate downward slowly, avoiding excessive shaking of the photosensitive resin due to excessive rotation speed of the material tank, which could cause it to overflow the material tank.

[0041] A drive wheel 26 is located at the lower part of the ball screw 22, above the servo motor 21. In this embodiment, the drive wheel is integrally formed on the ball screw 22. It is understood that in other embodiments, a separate drive wheel may be provided and fixedly mounted on the ball screw.

[0042] A set of transition gears 70 is installed on the workbench. This gear set includes a vertical shaft 71, a first transition gear 73, and a second transition gear 72. The vertical shaft 71 is rotatably mounted on the top plate via a set of angular contact bearings 75. After passing upward through the stepped surface 191, the vertical shaft 71 is secured with a locking nut 76, which stably suspends the vertical shaft on the top plate 13. The installation method of the vertical shaft is the same as that of the existing rotating shaft, and will not be described in detail.

[0043] A collar 77 is mounted on the vertical shaft. A first transition wheel 73 and a second transition wheel 72 are both sleeved on the vertical shaft, with the first transition wheel 73 located below the second transition wheel 72. A sleeve 78 is placed between the first and second transition wheels. A shaft end nut 74 is screwed onto the shaft end at the lower end of the vertical shaft, locking the first and second transition wheels onto the vertical shaft. The second transition wheel abuts against the collar. Second metal keys 711 are installed between the first and second transition wheels and the vertical shaft, respectively. In other words, both the first and second transition wheels are fixedly mounted on the vertical shaft, making them coaxial.

[0044] In this embodiment, both the driving pulley 26 and the first transition pulley 73 are synchronous belt pulleys, and the synchronous belt 79 wraps around the driving pulley and the first transition pulley, connecting the driving pulley and the first transition pulley. Both the second transition pulley 72 and the driven pulley 66 are external gears, with the second transition pulley meshing with the driven pulley. This allows the ball screw to drive the inner ring to rotate, thus causing the support cylinder and the material trough to rotate synchronously. When it is necessary to adjust the speed of the support cylinder and the material trough, the speed can be adjusted by replacing the first transition pulley with a different outer diameter and the corresponding synchronous belt. To avoid the synchronous belt specifications being incompatible with the replacement of the first transition pulley, a corresponding tensioning pulley can also be provided. The tensioning pulley can be set according to existing technology; however, in this embodiment, a tensioning pulley is not provided.

[0045] The ultraviolet (UV) light system is fixedly installed inside the worktable. The UV light system utilizes existing mature technology and is briefly described as follows: The UV light system includes an LCD screen 18 and a UV light source 14. The LCD screen is located directly below the material tank, and the UV light emitted by the UV light source can illuminate the LCD screen. To facilitate the installation of the LCD screen, a bracket 15 is provided. This bracket includes an annular ring 151 and a support column 152. The support column extends vertically, and its lower end is fixed to the base plate. The annular ring is fixed to the top of the support column. The annular ring 151 is located inside the cavity of the support cylinder 41, and there is a distance between the outer wall of the annular ring and the inner wall of the support cylinder to avoid interference with the rotation of the support cylinder. In this application, both the LCD screen 18 and the UV light source 14 are fixedly installed inside the worktable. The upper end of the annular ring is lower than the upper end of the support cylinder. At the lower end of the annular ring, there is a radially inward protruding annular flange 153. The LCD screen 18 is fixedly supported on the upper surface of the annular flange 153. The upper surface of the LCD screen is 1mm lower than the upper end of the support cylinder, so that the LCD screen does not contact the material tank, thereby avoiding the light-transmitting stripping plate of the material tank from directly pressing against the LCD screen and causing scratches on the surface of the LCD screen.

[0046] The material trough and the support cylinder are coaxially arranged. The first central axis 311 of the material trough is collinear with the central axis of the slewing bearing 60. In this embodiment, the first central axis 311 and the second central axis 171 of the printing platform 17 are parallel to each other and have a distance H, so that the material trough and the printing platform are not coaxial. Specifically, in this embodiment, the distance H between the first central axis 311 and the second central axis 171 is 6mm. In other embodiments, the distance H between the first central axis and the second central axis is preferably 5-15mm. The specific distance H can be selected according to the size of the material trough. The larger the material trough, the larger the distance H between the first central axis and the second central axis, but there are no special requirements for the specific selection. Figure 2 In the diagram, for clarity, both the second central axis 171 and the first central axis 311 are represented by a small circle, and in... Figure 2 In the diagram, the position of the printing platform within the material trough is indicated by a dashed line.

[0047] To avoid excessive tilting of the trough under unrestricted conditions, which could lead to overflow of the photosensitive resin, the maximum angle between the trough and the horizontal plane is 6° in this embodiment. When the model has an irregular shape, the different shapes of each cured layer during printing result in different bonding areas between each cured layer and the release film, leading to varying adhesive forces. Therefore, the tilt angle of the trough will differ during the peeling process of each cured layer and the release film. When the bonding area between the cured layer and the release film is small, the model and the release film may have already peeled off before the tilt angle of the trough reaches its maximum value. Conversely, when the bonding area between the cured layer and the release film is large, the tilt angle of the trough must reach its maximum value before the model and the release film can be peeled off. This application only limits the maximum tilt angle of the trough. In actual operation, the tilt angle of the trough can be freely set within the maximum tilt range during the peeling process of each cured layer and the release film, without deliberate restriction.

[0048] The following describes the photopolymerization 3D printing method of this application. This photopolymerization 3D printing method uses the aforementioned photopolymerization 3D printing apparatus and includes the following steps:

[0049] (1) Make the material tank horizontal, start the servo motor of the transmission device, immerse the printing platform into the photosensitive resin in the material tank, and complete the printing of the first curing layer on the printing platform.

[0050] When the servo motor rotates, it also drives the material tank to rotate. However, during the printing of the curing layer, the servo motor is in a stopped state, which keeps the material tank stationary and does not affect the printing process.

[0051] (2) The servo motor rotates forward, driving the ball screw to rotate, causing the printing platform to move upward, and at the same time driving the material tank to rotate; when the printing platform moves upward, it drives the material tank to rotate around the hinge shaft, causing the end of the material tank away from the hinge shaft to move upward, causing the material tank to tilt, so that the first cured layer is completely peeled off from the release film of the material tank.

[0052] When the material tank tilts, the lower end face of the first cured layer forms an angle with the horizontal plane, creating a V-shaped gap between the first cured layer and the release film. This gap gradually widens until the first cured layer completely separates from the release film. Because the material tank rotates synchronously with the support cylinder during the tilting process, the angle between the lower end face of the first cured layer and the horizontal plane also rotates synchronously, further improving the release film peeling speed.

[0053] (3) Under the action of the viscous damper, the end of the material trough away from the hinge axis moves slowly downward, causing the material trough to rotate downward and return to the horizontal state; at the same time, the servo motor reverses and lowers the printing platform so that the distance between the first curing layer and the release film reaches the thickness of one curing layer, and then the printing of the second curing layer is completed.

[0054] (4) Repeat steps (2) and (3) until the model is printed.

[0055] Specifically, in this embodiment, the number of rotations of the material tank during the peeling process of each cured layer from the release film is 0.35 revolutions. It can be understood that in other embodiments, the number of rotations of the material tank during the peeling process of each cured layer from the release film can also be 0.25, 0.4, 0.5, 0.75, or 1 revolution, or of course, other numbers between 0.25 and 1 revolution.

[0056] As printing progresses, the height of the printing platform gradually increases. After each cured layer is printed, the support cylinder does not return to its original position but rotates by an angle, simultaneously rotating the material tray by an angle. This causes the printing position of the release film to rotate as well, preventing continuous printing in the same position on the release film. This maximizes the use of the release film and extends its service life.

Claims

1. A light-cured three-dimensional printing device, characterized by, The forming mechanism comprises a transmission device and a rotary support, the transmission device comprises a vertical rod fixed on the workbench, a ball screw rotatably mounted on one side of the vertical rod, and a servo motor mounted on the workbench for driving the ball screw to rotate; The rotary support comprises an outer ring and an inner ring combined by balls, the central axis of the rotary support extends in the vertical direction, the outer ring is fixed on the workbench, the support cylinder is fixed on the inner ring, the trough is mounted on the top end surface of the support cylinder, one side of the trough is hinged to the support cylinder through a hinge shaft, the central axis of the hinge shaft extends in the horizontal direction, and the trough can rotate around the hinge shaft; The printing platform is mounted on the ball screw through a ball nut, when the printing platform carrying the model moves upward, it can drive the trough to move upward away from the end of the hinge shaft, so that the trough is inclined; The ball screw has a driving wheel, and the inner ring has a driven wheel, the driving wheel is connected to the driven wheel, so that the ball screw can drive the inner ring to rotate and drive the support cylinder and the trough to rotate synchronously; An ultraviolet light system is fixedly installed in the workbench, the ultraviolet light system comprises a liquid crystal screen and an ultraviolet light source, the liquid crystal screen is located directly below the trough, and the ultraviolet light emitted by the ultraviolet light source can irradiate the liquid crystal screen.

2. The printing device according to claim 1, characterized by A limiting mechanism is installed on the support cylinder, which is used to limit the inclination angle of the trough.

3. The printing device of claim 2, wherein, The limiting mechanism and the hinge shaft are located on opposite sides of the trough, the limiting mechanism comprises a limiting piece, one end of the limiting piece is fixed on the support cylinder, the other end of the limiting piece is a limiting end, and the limiting end is located above the trough wall, when the end of the trough away from the hinge shaft moves upward, it can abut against the limiting end.

4. The printing device of claim 3, wherein, The limiting mechanism further comprises a viscous damper, the piston rod and the cylinder of the viscous damper are hinged to the trough wall and the rotating cylinder respectively; when the trough rotates upward, the piston rod of the viscous damper is elongated, when the model and the release film of the trough are completely separated, under the action of gravity, the end of the trough away from the hinge shaft moves downward and abuts against the rotating cylinder, and the piston rod of the viscous damper is retracted.

5. The printing device of claim 1, wherein, The central axis of the trough and the central axis of the printing platform have a distance.

6. The printing device of claim 1, wherein, When the trough is inclined, the maximum included angle between the trough and the horizontal plane is 4-8°.

7. The printing device of claim 1, wherein A transition gear set is installed on the workbench, the gear set comprises coaxially arranged first and second transition gears, the driving wheel is connected to the first transition gear, and the second transition gear is connected to the driven wheel.

8. The printing device of claim 7, wherein, The driving wheel and the first transition gear are synchronous pulleys, a synchronous belt is wound around the driving wheel and the first transition gear, and the second transition gear and the driven wheel are external gears, the second transition gear is engaged with the driven wheel.

9. A method of photocuring three-dimensional printing, characterized by The printing method comprises the following steps: (1) The trough is in a horizontal state, the transmission device is started, the printing platform is immersed in the photosensitive resin in the trough, and the printing of the first solidified layer on the printing platform is completed; (2) The servo motor is turned on, the ball screw is driven to rotate, the printing platform moves upward, and the trough is driven to rotate; When the printing platform moves upward, the material tank rotates around the hinge shaft, and the end of the material tank away from the hinge shaft moves upward, so that the material tank is inclined, and the first solidified layer is separated from the release film of the material tank; (3) The material tank rotates downward and returns to the horizontal state; the servo motor is reversed synchronously, and the printing platform is lowered, so that the distance between the first solidified layer and the release film reaches the thickness of a solidified layer, and the printing of the second solidified layer is completed; (4) Steps (2) and (3) are repeated until the printing of the model is completed.

10. The printing method according to claim 9, characterized by, During the separation of each solidified layer from the release film, the number of rotation of the material tank is 0.25-1 circle.

Images