A 3D printing platform with a reinforced screw

Abstract

This application is a divisional application, which proposes a 3D printing platform with a reinforced screw, which includes a printing platform mounted on a connecting arm of a transmission mechanism; a guide rod hole is provided on the printing platform, the guide rod hole extending in the vertical direction and passing through the upper and lower sides of the printing platform; an internal threaded part is detachably mounted on the printing platform, and the reinforced screw is screwed into the internal threaded hole of the internal threaded part; a driving device for driving the reinforced screw to rotate is also mounted on the printing platform; a model is bonded to the printing platform, and a reinforced hole is formed in the model; driven by the driving device, the reinforced screw can move back and forth in the vertical direction and screw the reinforced screw into the reinforced hole or withdraw from the model. This application can effectively reduce or even avoid the problem of the model breaking, cracking, or even detaching from the printing platform due to the influence of gravity and the adhesive force of the release film during the printing process.

Description

[0001] This application is a divisional application. The application date of the original application is September 27, 2024, the application number is 202411358714X, and the name of the invention is: An enhanced 3D printer and an enhanced 3D printing method. Technical Field

[0002] The present invention relates to 3D printing technology, and in particular to a 3D printing platform with a reinforced screw. Background Art

[0003] 3D printing methods such as DLP and LCD / LED project a surface imaging beam based on a sliced ​​cross-sectional pattern of a 3D model onto a photosensitive resin print material to achieve single-layer curing. Layers of this curing are then stacked to form a 3D model. During the printing process, the unfinished model needs to be frequently lifted upward to free the model from the release film and allow the photosensitive resin to enter between the model and the release film to continue printing the next cured layer. This frequent lifting process subjects the model interior and the space between the model and the print platform to frequent tensile stresses, causing the model to crack or break, and even detach from the print platform. To prevent cracking, breakage, or detachment of unfinished models, the contact surface between the print platform and the model is often roughened to improve the adhesion between the model and the print platform. While this approach can prevent detachment to a certain extent, it cannot prevent detachment of the model from thinner cross-sections. While adding auxiliary support ribs can improve the overall strength of the model, it cannot prevent detachment, especially detachment from the print platform, which can lead to printing failure. Therefore, how to avoid the breakage of the model itself and the generation of cracks or even separation between the model and the printing platform during the printing process remains a problem to be solved in this field. Summary of the Invention

[0004] To address the problem of models breaking, cracking, or even detaching from the printing platform during printing in the prior art, the present application proposes a 3D printing platform with a reinforced screw, which includes a printing platform detachably mounted on a connecting arm of a transmission mechanism. The lower surface of the printing platform forms a working surface, and the connecting arm can drive the printing platform to reciprocate in the vertical direction.

[0005] A guide rod hole is formed on the printing platform, extending vertically and penetrating the upper and lower sides of the printing platform. An internally threaded member is detachably mounted on the printing platform, having an internally threaded hole coaxially arranged with the guide rod hole. A reinforcing screw is screwed into the internally threaded hole of the internally threaded member and is capable of downwardly passing through the guide rod hole. A driving device is also mounted on the printing platform for driving the reinforcing screw to rotate. A model is bonded to the printing platform, and a reinforced hole is formed within the model. Driven by the driving device, the reinforcing screw can reciprocate in the vertical direction. When the reinforcing screw moves downward, it can extend downward from the guide rod hole and screw into the reinforced hole. When the reinforcing screw moves upward, it can withdraw from the model, and the lower end of the reinforcing screw can be retracted into the guide rod hole. Specifically, the reinforcing screw is made of a metal or alloy material such as steel, copper, or aluminum.

[0006] In this application, a reinforcing screw is provided on the printing platform and is capable of being screwed downward into the model. The high strength of the reinforcing screw is utilized to improve the connection strength between the model and the printing platform. After printing is completed, the reinforcing screw is withdrawn from the model so that the model can be removed from the printing platform. In the process of screwing the reinforcing screw into the reinforcement hole, some resin debris will inevitably be produced. These resin debris will fall into the resin in the trough. In order to facilitate the cleaning of these numerical debris, the trough is fixedly mounted on the workbench. The trough is rectangular, and the inner cavity of the trough is divided into a working area and a non-working area surrounding the working area. A scraper is installed in the trough. The scraper can move from one side of the trough to the other side to push the solid particles deposited at the bottom of the trough from the working area to the non-working area; in the vertical direction, the projection of the printing platform is located in the working area. The scraper is used to push the solid particles such as resin debris that fall and deposited at the bottom of the trough from the working area to the non-working area to prevent the model from being pressed by larger solid particles during the descent process, thereby damaging the release film. To prevent resin debris generated by the scraper from being retained in the work area during its operation, the reinforcing screw stops rotating and remains stationary after each curing layer is printed and before the next curing layer is printed. The reinforcing screw only rotates during the printing process of each curing layer to screw the model downward.

[0007] Because the reinforcing screw can be screwed into the model, the model has higher tensile strength during the printing process, which can effectively reduce or even avoid cracks or even breakage of the model due to the influence of gravity and the adhesive force of the release film during the printing process.

[0008] This application separately sets up an internal threaded part on the printing platform, and different internal threaded parts can be replaced according to the different outer diameters and thread forms of the reinforcing screw to facilitate printing of models of different types.

[0009] Furthermore, the reinforcing screw is a hollow screw with a downward opening, and the inner cavity of the reinforcing screw can accommodate part of the resin powder generated during the screwing process of the reinforcing screw, thereby reducing the amount of resin powder falling into the trough.

[0010] Specifically, the transmission mechanism has a ball screw extending in a vertical direction, a connecting arm is engaged with the ball screw, a free end of the connecting arm is formed as a working end, and the printing platform is detachably mounted on the working end;

[0011] The end of the connecting arm away from the ball screw has two holding arms arranged at intervals in the horizontal direction. The two holding arms extend in a direction away from the ball screw and are parallel to each other. A platform accommodating cavity is formed between the two holding arms. The platform accommodating cavity has an opening facing away from the ball screw. Corresponding to each holding arm, a card slot is provided on opposite sides of the printing platform. The printing platform is inserted into the platform accommodating cavity, and each holding arm is inserted into the corresponding card slot. Each holding arm is fixed to the printing platform by bolts, and the drive device is installed on the upper surface of the printing platform.

[0012] In this design, the printing platform is mounted on the connecting arm using a clamping arm, thereby leaving the top of the printing platform free so that the reinforcing screw can be smoothly screwed down from the top of the printing platform into the model, and the driving device can be mounted on the upper surface of the printing platform so that the driving device can be conveniently connected to the reinforcing screw and drive the reinforcing screw so that the reinforcing screw can be screwed into the reinforcement hole of the model.

[0013] Specifically, the driving device includes a driving member and a solid shaft servo motor. The driving member is rotatably mounted on the upper side of the printing platform via a bearing. The driving member has an axis-through hole, and the reinforcing screw freely passes through the axis-through hole. One side of the reinforcing screw has a cutting plane, and a protrusion is provided in the axis-through hole. The solid shaft servo motor is fixedly mounted on the upper side of the printing platform and located on one side of the driving member. The output shaft of the solid shaft servo motor is connected to the driving member. When the solid shaft servo motor drives the driving member to rotate, the protrusion can press against the cutting plane and drive the reinforcing screw to rotate. Under the restriction of the internal threaded member, the reinforcing screw can reciprocate in the vertical direction while rotating. Or,

[0014] The driving device includes a driving member and a hollow shaft torque motor, which includes a stator and a mover rotatably arranged in the stator, an outer hollow shaft fixed on the mover, and an inner hollow shaft fixed on the outer hollow shaft. The outer hollow shaft, the inner hollow shaft and the guide rod hole are coaxially arranged, and the driving member is detachably fixed on the inner hollow shaft. The driving member has a through-axis hole, and the reinforcing screw freely passes through the through-axis hole. One side of the reinforcing screw has a cutting plane, and a radially outward protrusion is provided in the through-axis hole; when the mover drives the driving member to rotate, the protrusion can be pressed against the cutting plane and drive the reinforcing screw to rotate, and under the restriction of the internal threaded member, the reinforcing screw moves back and forth in the vertical direction while rotating. The hollow shaft torque motor is a servo motor.

[0015] The above two structural forms of the driving device can both meet the driving needs of the reinforcing screw and can be selected according to the specific structure of the equipment and usage habits.

[0016] The enhanced 3D printing method performed using any of the enhanced 3D printers described above comprises the following steps:

[0017] (1) After the 3D modeling of the model to be printed is completed, a cylindrical reinforcement area with a set diameter is calculated, and the reinforcement area can extend to at least one outer end surface of the model to be printed. The extension direction of the reinforcement area is perpendicular to the outer end surface, and the outer end surface is used as the starting surface for model printing;

[0018] (2) Printing the model to be printed with the outer end surface as the starting surface, forming a reinforcement hole in the reinforcement area during the printing process of the solidified layer of the model, wherein the reinforcement hole is coaxially arranged with the reinforcing screw, and the inner diameter of the reinforcement hole is less than the outer diameter of the thread of the reinforcing screw; rotating the reinforcing screw to screw the reinforcing screw into the reinforcement hole; and keeping the reinforcing screw stationary during the printing interval between two adjacent solidified layers;

[0019] After each solidified layer is printed, the printing platform is lifted upwards. After the solidified layer is separated from the release film of the trough, the scraper is started and moved from one side of the trough to the opposite side, pushing the solid particles deposited at the bottom of the trough from the working area to the non-working area.

[0020] (3) When printing is completed, the reinforcing screw is withdrawn from the printed model.

[0021] In the 3D printing method of the present application, during the printing process, the reinforcing screw is screwed into the model, and the high strength of the reinforcing screw is used to improve the connection strength between the model and the printing platform. After printing is completed, the reinforcing screw is withdrawn from the model so that the model can be removed from the printing platform. In the process of the reinforcing screw being screwed into the reinforcement hole, some resin debris will inevitably be produced. These resin debris will fall into the resin in the material tank. A scraper is used to push the solid particles such as the resin debris that fall and deposited at the bottom of the material tank from the working area to the non-working area to avoid the model being pressed against larger solid particles during the descent process, thereby causing damage to the release film. In order to avoid the resin debris generated during the scraper operation being trapped in the working area, the reinforcing screw stops rotating and remains stationary after each solidified layer is printed and before the next solidified layer is printed. The reinforcing screw is only rotated during the printing process of each solidified layer to screw downward on the model.

[0022] Since the reinforced screw can be screwed into the model, the model also has higher tensile strength during the printing process, which can effectively reduce or even avoid cracks or even breakage of the model due to the influence of gravity and the adhesive force of the release film during the printing process.

[0023] The present application utilizes the good toughness of the resin so that when the reinforcing screw is screwed in the reinforcement hole, the threads of the reinforcing screw are cut to form an internal thread that meshes with the threads of the reinforcing screw.

[0024] Furthermore, to prevent cracks or breakage in the mold when the reinforcing screw is screwed into the reinforcement hole, the diameter of the reinforcement area is set to be ≥10mm larger than the outer diameter of the reinforcement screw. This design ensures that the wall thickness of the reinforcement hole is at least 5mm, ensuring that the area where the reinforcement hole is located still has high strength to withstand the downward thrust generated by the reinforcement screw during the screwing process.

[0025] Furthermore, to ensure smooth insertion of the reinforcing screw into the mold, D1 - D2 = (0.5 - 1) W, where D1 is the outer diameter of the reinforcing screw thread, D2 is the inner diameter of the reinforcement hole, and W is the height of the reinforcing screw thread. Because the mold is a resin product with a certain degree of deformation, even if the difference between D1 and D2 is less than W, the resin's deformation capacity can still form a complete thread. The difference between D1 and D2 is determined based on the resin's deformation capacity. In specific embodiments, corresponding experiments are required to determine the difference between D1 and D2.

[0026] Furthermore, to ensure the integrity of the model appearance, the lower end of the reinforced hole is a closed end, and the wall thickness of the closed end is 0.5-2 mm.

[0027] Furthermore, to prevent the reinforcing screw from contacting the release film of the trough during printing, the distance between the lower end of the reinforcing screw and the layer to be printed and cured is 2-5 mm. This ensures that the reinforcing screw always maintains a certain distance from the layer to be printed and cured, while ensuring the strength of the model and smooth printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 3D printer according to an embodiment of the present invention.

[0029] Figure 2 yes Figure 1 Connection structure diagram between the middle drive device and the printing platform.

[0030] Figure 3 yes Figure 2 Center AA view.

[0031] Figure 4 It is a structural diagram of the connecting arm.

[0032] Figure 5 This is a structural diagram of the connection between the drive member and the reinforcing screw.

[0033] Figure 6 This is a top view of the trough.

[0034] Figure 7 yes Figure 6 View from the middle BB direction.

[0035] Figure 8 2 is a schematic structural diagram of another embodiment of the enhanced 3D printer of the present invention. DETAILED DESCRIPTION

[0036] Example 1

[0037] See also Figure 1-Figure 7 An enhanced 3D printer includes a workbench 11, on which is mounted a transmission mechanism. The transmission mechanism utilizes existing mature technology and includes a vertical rod 12 fixed to the workbench 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 engages with the ball screw through 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 is mounted at the lower end of the ball screw, which is fixedly mounted on the vertical rod. The servo motor can drive the ball screw to rotate, allowing the connecting arm to drive the printing platform to reciprocate in the vertical direction.

[0038] The trough 17 is fixedly mounted on the workbench. The trough 17 is rectangular and specifically includes a trough wall 171 extending in the vertical direction. A release film 174 is provided at the bottom of the trough wall. A trough flange 175 is provided on the outside of the bottom of the trough wall. Bolts pass through the trough flange 175 and are screwed onto the workbench to detachably fix the trough to the workbench. The inner cavity of the trough is divided into a working area 173 and a non-working area 172, wherein the non-working area surrounds the working area. Figure 6 In FIG, a double-dotted dashed line 176 is used as the dividing line between the working area 173 and the non-working area 172. In the vertical direction, the projection of the printing platform is located in the working area.

[0039] A scraper system 18 is also mounted on the workbench. The scraper system 18 includes a scraper 181 positioned within the trough, parallel to one sidewall of the trough wall 171. A screw 183 and a slide rail 185 are positioned at either end of the scraper's length. Both the screw and the slide rail are located outside the trough. The screw is rotatably mounted on the workbench via a bearing, while the slide rail is fixedly mounted on the workbench. Both the screw and the slide rail are perpendicular to the length of the scraper. A first U-shaped arm 182 is connected to one end of the scraper's length, engaged with the screw via a screw nut. A second U-shaped arm 186 is connected to the other end of the scraper's length, slidably supported on the slide rail via a slide groove. One end of the screw is fixedly connected to the output shaft of a drive motor 184, which is mounted on the workbench. The blade of the scraper abuts the release film. Driven by a drive motor, the lead screw drives the scraper from one side of the trough to the other, pushing solid particles deposited at the bottom of the trough from the working area to the non-working area. A UV light system is installed within the workbench. This UV light system includes an LCD screen fixed to the top plate of the workbench, and the trough is arranged above the LCD screen. The UV light system is not shown in the attached drawings. The UV light system uses existing mature technology and will not be described in detail.

[0040] In this embodiment, the printing platform 20 includes a main body 21, a connecting portion 24 and a model plate 23, wherein the connecting portion 24 is integrally formed on the upper side of the main body 21, and a platform flange 22 is provided on the lower side of the main body 21. The model plate 23 is detachably mounted on the platform flange 22 by bolts, and the lower surface of the model plate 23 is formed as a working surface 231.

[0041] In this embodiment, two holding arms 141 are arranged at intervals in the horizontal direction at one end of the connecting arm 14 away from the ball screw. The two holding arms 141 extend in a direction away from the ball screw and are parallel to each other. A platform accommodating cavity 142 is formed between the two holding arms. The platform accommodating cavity has an opening facing away from the ball screw. Corresponding to each holding arm 141, a clamping groove 25 is respectively provided on the opposite sides of the printing platform. The clamping groove is specifically provided on the opposite sides of the connecting portion 24. The printing platform 20 is inserted into the platform accommodating cavity 142, and each holding arm 141 is inserted into the corresponding clamping groove 25. The first bolt 16 passes through the holding arm and is screwed into the first screw hole 251 located in the clamping groove, so that the holding arm is detachably fixed to the printing platform. To avoid shaking, each holding arm is fixed to the printing platform by two first bolts.

[0042] The print platform has guide rod holes formed on it. These holes include an upper guide rod hole 27 in the main body and a lower guide rod hole 28 in the mold plate. Both holes are coaxially arranged. The upper guide rod hole 27 extends upward through the upper surface of the connecting portion 24, while the lower guide rod hole 28 extends downward through the lower surface of the mold plate 23. In other words, the guide rod holes extend vertically through both the upper and lower sides of the print platform.

[0043] The upper end of the upper guide rod hole 27 is radially expanded to form an embedded hole, into which an internally threaded member 26 is tightly inserted. The internally threaded member 26 has an internally threaded hole that is coaxially arranged with the guide rod hole. Specifically, in this embodiment, the internally threaded member is a hexagonal nut, and the inner peripheral wall of the embedded hole is a hexagon with the same shape as the outer peripheral surface of the hexagonal nut. The inner diameter of the internally threaded hole is smaller than the inner diameter of the guide rod hole. The corresponding internally threaded member can be replaced according to the different thicknesses and different types of thread threads of the reinforcing screw. To facilitate the installation of the hollow shaft torque motor 70 described below, the upper surface of the internally threaded member 26 is not higher than the upper surface of the connecting portion, that is, the upper surface of the internally threaded member 26 is not higher than the upper surface of the printing platform.

[0044] The drive device is mounted on the upper surface of the printing platform. Specifically, in this embodiment, the drive device includes a first drive member 83 and a hollow shaft torque motor 70, which is a servo motor. The hollow shaft torque motor 70 includes a stator 71 and a mover 75 rotatably disposed within the stator 71. An outer hollow shaft 86 is fixed to the mover 75. An upper end cap 72 and a lower end cap 73 are mounted at the upper and lower ends of the stator 71, respectively. The upper end cap 72 is bolted to an upper flange 711 at the upper end of the stator 71, and the lower end cap 73 is bolted to a lower flange 712 at the lower end of the stator 71. The upper flange 711 and the lower flange 712 are integrally formed on the stator 71. A winding 74 is disposed on the inner side of the stator.

[0045] In this embodiment, an upper connecting flange 76 is provided on the outer peripheral surface of the outer hollow shaft 86, and the upper end cover has an upper abutting flange 721 protruding inward, and the lower surface of the upper abutting flange 721 is a step surface facing downward. The upper abutting flange 721 is pressed against the upper side of the outer ring of the upper angular contact bearing 78 through its lower surface, and the upper connecting flange 76 is pressed against the lower side of the inner ring of the upper angular contact bearing, so that the upper end cover is rotatably connected to the outer hollow shaft 86 through the upper angular contact bearing.

[0046] A lower step 77 is provided at the lower end of the outer hollow shaft 86. This step has a downwardly facing stepped surface and is formed by a radially inward depression of the outer circumference of the outer hollow shaft 86. The lower end cap has an inwardly projecting lower abutment flange 731. The upper surface of the lower abutment flange 731 is an upwardly facing stepped surface. The lower abutment flange 731 abuts the lower side of the outer ring of the lower angular contact bearing 79 via its upper surface. The lower step 77 presses against the lower side of the inner ring of the lower angular contact bearing, thereby rotatably connecting the lower end cap to the outer hollow shaft 86 via the lower angular contact bearing. The structure of the hollow shaft torque motor can be completed using existing mature technologies and will not be described in detail.

[0047] The lower end cover 73 is detachably mounted on the upper surface of the connecting portion via bolts, thereby mounting the hollow shaft torque motor 70 on the upper surface of the connecting portion.

[0048] The inner hollow shaft 81 is lined within the inner cavity of the outer hollow shaft 86. A flange 811 is provided at the top of the inner hollow shaft 81. This flange 811 is formed by a radially outward protrusion from the outer circumference of the inner hollow shaft 81. The top of the outer hollow shaft is bolted to this flange 811. To ensure the stability of the connection between the inner and outer hollow shafts, a key 85 is provided between the inner and outer hollow shafts. The outer hollow shaft, inner hollow shaft, and guide rod hole are coaxially arranged.

[0049] The top of the inner cavity of the inner hollow shaft has a regular hexagonal countersunk hole 812, and the outer wall of the top of the inner hollow shaft is provided with an external thread 82. A first driving member 83 is accommodated in the countersunk hole. A pressure cap 84 is screwed onto the external thread to retain the first driving member 83 in the countersunk hole, allowing the first driving member to be removably mounted on the inner hollow shaft. The first driving member has an outer circumferential surface with the same shape as the countersunk hole, so that the inner hollow shaft can drive the first driving member to rotate synchronously. The first driving member has a first through-shaft hole 831. When viewed along the axial direction of the first through-shaft hole, the cross-section of the first through-shaft hole 831 includes a major arc 832 and a straight line segment 833 that encloses the major arc 832, so that the first through-shaft hole is formed by a circular hole and has a radially inward protrusion within the circular hole, wherein the area where the straight line segment is located forms the protrusion.

[0050] The reinforcing screw 40 freely passes through the first through-shaft hole and is screwed into the internal threaded hole of the internal threaded member, and can pass downward through the guide rod hole. On one side of the reinforcing screw 40, there is a tangent plane 41 that can adapt to the above-mentioned protrusion. When the mover drives the first driving member to rotate through the inner hollow shaft, the protrusion can press against the tangent plane and drive the reinforcing screw to rotate. Under the restriction of the internal threaded member, the reinforcing screw can reciprocate in the vertical direction while rotating. The model 30 is bonded to the printing platform, and a reinforced hole 31 is formed in the model. When the reinforcing screw moves downward, the reinforcing screw can extend downward from the guide rod hole and screw into the reinforced hole 31; when the reinforcing screw moves upward, it can withdraw from the model 30 and retract the lower end of the reinforcing screw into the guide rod hole. In this embodiment, the reinforcing screw 40 is a stainless steel hollow screw. It can be understood that in other embodiments, the reinforcing screw can also be made of metal or alloy materials such as copper and aluminum.

[0051] For details about the reinforced holes 31 , please refer to the relevant content in Example 3 below.

[0052] Example 2

[0053] See also Figure 8 This embodiment is basically the same as the first embodiment, the only difference being the driving device. Figure 8 and Figure 1-Figure 5 The same figure marks represent the same technical features. In this embodiment, the driving device includes a second driving member 66 and a solid shaft servo motor 61. A bearing seat 64 is fixedly installed on the upper surface of the connecting portion 24 of the printing platform by bolts, and the second driving member 66 is rotatably mounted on the bearing seat 64 via a rolling bearing 65. The solid shaft servo motor 61 is fixedly mounted on the upper side of the printing platform and on one side of the second driving member. A pulley 62 is fixedly mounted on the driving shaft of the solid shaft servo motor, and a belt 63 is wrapped around the pulley and the second driving member. A belt groove is provided on the outer peripheral surface of the second driving member, and the belt is clamped in the belt groove. It can be understood that the pulley 62 can also be replaced with a gear, and meshing gears are provided on the second driving member to form a gear combination. The solid shaft servo motor 61 drives the second driving member to rotate via the gear combination.

[0054] The second driving member has a second through-axis hole 661 , and the structure of the second through-axis hole is the same as that of the first through-axis hole. For details, please refer to the relevant description in Example 1 and will not be repeated here.

[0055] The reinforcing screw 40 freely passes through the second through-shaft hole and is screwed into the internally threaded hole of the internally threaded member. The reinforcing screw in this embodiment has the same structure as that in Example 1. When the solid-shaft servo motor drives the driving member to rotate, the protrusion can press against the tangent plane and drive the reinforcing screw to rotate. Under the restraint of the internally threaded member, the reinforcing screw can reciprocate in the vertical direction while rotating.

[0056] Example 3

[0057] This embodiment describes an enhanced 3D printing method, which is performed using the enhanced 3D printer in Embodiment 1 or Embodiment 2. The enhanced 3D printing method includes the following steps:

[0058] (1) After the 3D modeling of the model to be printed is completed, a cylindrical reinforcement area with a set diameter is calculated. Figure 3 ,exist Figure 3 In the model 30 shown, the area enclosed by the dotted line 91 is the reinforced area. For clarity, the dotted line 91 extends upward to the model plate 23 and downward to the bottom of the model 30. For clarity, the model 30 is not provided with a cross-section line.

[0059] The outer diameter of the reinforcing screw is 5 mm, the height of the thread of the reinforcing screw is about 0.49 mm, the set diameter of the reinforced area is 20 mm, and the reinforced area extends to an outer end face 35 of the model to be printed. The extension direction of the reinforced area is perpendicular to the outer end face, and the outer end face can be used as the starting surface when printing the model.

[0060] (2) The model to be printed is printed with the outer end surface as the starting surface. During the printing process of the solidified layer of the model, a reinforcement hole 31 is formed in the reinforcement area. The reinforcement hole 31 is coaxially arranged with the reinforcing screw. The reinforcing screw is rotated so that the reinforcing screw extends downward out of the guide rod hole and is screwed into the reinforcing hole. During the printing interval between two adjacent solidified layers, the reinforcing screw remains stationary.

[0061] That is, after completing the printing of one solidified layer, the reinforcing screw is stopped from rotating before printing the next solidified layer, so that the reinforcing screw remains stationary to prevent the resin debris generated on the model from falling into the material trough when the reinforcing screw rotates. As a result, when the model descends, the model squeezes the resin debris and causes damage to the release film.

[0062] As printing progresses, the reinforcement holes extend as the model lengthens, and the reinforcement screws continue to screw downward.

[0063] In this embodiment, the inner diameter of the reinforcement hole is 4.6 mm, that is, the inner diameter of the reinforcement hole is less than the outer diameter of the reinforcement screw by about 0.82 thread heights of the reinforcement screw.

[0064] After each solidified layer is printed, the printing platform is lifted upwards. After the solidified layer is separated from the release film of the trough, the scraper system is started to move the scraper from one side of the trough to the opposite side, pushing the solid particles deposited at the bottom of the trough from the working area to the non-working area.

[0065] When the reinforcing screw is rotated in the reinforcement hole, some resin debris will inevitably be produced. These vertical debris will fall into the resin in the material tank. During the printing process of the fixed layer, when the reinforcing screw is rotated at the same time, the resin debris generated will not affect the printing. Before printing the next solidified layer, a scraper is used to push the resin debris that falls into the material tank from the working area to the non-working area, thereby avoiding damage to the release film and ensuring continuous printing.

[0066] (3) When printing is completed, the reinforcing screw is withdrawn from the printed model and the lower end of the reinforcing screw is retracted into the guide rod hole.

[0067] In order to maintain the integrity of the model appearance, the lower end of the reinforced hole is a closed end 33. In this embodiment, the wall thickness H of the closed end is 1.5 mm.

[0068] In this embodiment, in order to prevent the reinforcing screw from touching the release film and causing damage to the release film during the printing process, the distance S between the lower end surface of the reinforcing screw and the to-be-printed and cured layer is 3 mm.

[0069] When the reinforcing screw retracts into the guide rod hole, it will carry a small amount of resin. To prevent the resin from adhering to the inner wall of the guide rod hole, the resin in the guide rod hole needs to be cleaned after the model is printed.

Claims

1. A 3D printing platform with a reinforced screw, characterized in that: The printing platform comprises a printing platform detachably mounted on a connecting arm of a transmission mechanism, wherein the lower surface of the printing platform is formed as a working surface, and the connecting arm is capable of driving the printing platform to move back and forth in a vertical direction; A guide rod hole is formed on the printing platform, extending in a vertical direction and passing through the upper and lower sides of the printing platform. An internal threaded member is detachably mounted on the printing platform, the internal threaded member having an internal threaded hole coaxially arranged with the guide rod hole. A reinforcing screw is screwed into the internal threaded hole of the internal threaded member and can pass downward through the guide rod hole. A driving device for driving the reinforcing screw to rotate is also mounted on the printing platform. The model is bonded to the printing platform, and a reinforcement hole is formed in the model; driven by the driving device, the reinforcement screw can reciprocate in the vertical direction. When the reinforcement screw moves downward, it can extend downward from the guide rod hole and be screwed into the reinforcement hole; when the reinforcement screw moves upward, it can withdraw from the model and retract the lower end of the reinforcement screw into the guide rod hole.

2. The 3D printing platform according to claim 1, characterized in that: The reinforcing screw is a hollow screw that opens downward.

3. The 3D printing platform according to claim 1, characterized in that: The transmission mechanism has a ball screw extending in a vertical direction, a connecting arm engaged with the ball screw, a free end of the connecting arm forming a working end, and a printing platform detachably mounted on the working end; The end of the connecting arm away from the ball screw has two holding arms arranged at intervals in the horizontal direction. The two holding arms extend in a direction away from the ball screw and are parallel to each other. A platform accommodating cavity is formed between the two holding arms. The platform accommodating cavity has an opening facing away from the ball screw. Corresponding to each holding arm, a card slot is provided on opposite sides of the printing platform. The printing platform is inserted into the platform accommodating cavity, and each holding arm is inserted into the corresponding card slot. Each holding arm is fixed to the printing platform by bolts, and the drive device is installed on the upper surface of the printing platform.

4. The 3D printing platform according to claim 3, characterized in that: The driving device includes a driving member and a solid shaft servo motor. The driving member is rotatably mounted on the upper side of the printing platform via a bearing. The driving member has an axis through-hole, and the reinforcing screw freely passes through the axis through-hole. One side of the reinforcing screw has a cutting plane, and a protrusion is provided in the axis through-hole; the solid shaft servo motor is fixedly mounted on the upper side of the printing platform and on one side of the driving member. The output shaft of the solid shaft servo motor is connected to the driving member. When the solid shaft servo motor drives the driving member to rotate, the protrusion can be pressed against the cutting plane and drive the reinforcing screw to rotate. Under the restriction of the internal threaded member, the reinforcing screw can reciprocate in the vertical direction while rotating.

5. The 3D printing platform according to claim 3, characterized in that: The driving device includes a driving member and a hollow shaft torque motor, which includes a stator and a mover rotatably arranged in the stator, an outer hollow shaft fixed on the mover, and an inner hollow shaft fixed on the outer hollow shaft. The outer hollow shaft, the inner hollow shaft and the guide rod hole are coaxially arranged, and the driving member is detachably fixed on the inner hollow shaft. The driving member has a through-axis hole, and the reinforcing screw freely passes through the through-axis hole. One side of the reinforcing screw has a cutting plane, and a radially outward protrusion is provided in the through-axis hole; when the mover drives the driving member to rotate, the protrusion can be pressed against the cutting plane and drive the reinforcing screw to rotate, and under the restriction of the internal threaded member, the reinforcing screw moves back and forth in the vertical direction while rotating. The hollow shaft torque motor is a servo motor.

6. The 3D printing platform according to claim 1, characterized in that: The reinforcing screw is made of metal or alloy material.

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