A printing method and device supporting hybrid printing of soft and hard heterogeneous materials

Abstract

The application discloses a printing method and device supporting mixed printing of soft and hard heterogeneous materials, and realizes independent picking and placing of hard sheets in space through adjustment of positive and negative air pressures, further combines with glue dropping and glue leveling, realizes creation of materials with complex heterogeneous microstructures, is innovative in a manufacturing method, can realize more ordered arrangement of hard components in a material domain, has high automation degree and high reliability, and is suitable for general materials without field response capability; can realize manufacturing of high-performance materials with complex microstructures, and can flexibly adjust the distribution direction and position of the hard components in the material domain according to needs, changes the situation that the spatial position of the hard components cannot be accurately controlled in a previous multi-material three-dimensional printing technical scheme, has simple operation and high reliability, and provides an important guarantee for development of high-performance materials.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing additive manufacturing technology, specifically relating to a printing method and apparatus that supports the printing of mixed soft and hard materials. Background Technology

[0002] Some biomaterials in nature (such as mother-of-pearl and bone) possess excellent comprehensive properties. This is fundamentally due to the presence of both high-strength, hard components and flexible, soft components within the material. These components, arranged in a highly ordered manner, constitute the material's microstructure, allowing it to maintain high strength while significantly enhancing toughness through energy dissipation mechanisms arising from its heterogeneous microstructure. Inspired by this, using multi-material 3D printing technology to precisely integrate hard and soft heterogeneous components, constructing intricate and ordered 3D structures at the microscale, is an effective approach for developing artificial high-performance materials. However, current multi-material 3D printing technology is still quite immature. Due to incompatible forming conditions (such as temperature), it is currently difficult to precisely integrate high-strength components, such as ceramics or glass, with polymer components possessing good flexibility in arbitrary forms. Instead, rigid components with fixed forms, such as particles, fibers, or sheets, are mixed with polymer prepolymers as reinforcing phases, utilizing the easily formable properties of polymers to manufacture multiphase materials. This results in the rigid components being randomly distributed and disordered within the material domain, failing to form a refined and ordered microstructure, thus limiting the improvement of material properties. Developing multi-material 3D printing technology that supports the ordered distribution of soft and hard heterogeneous components in three-dimensional space is of great significance for the development of high-performance materials.

[0003] Current multi-material 3D printing technologies primarily employ external field assistance to achieve the ordered distribution of rigid components. For example, by applying a magnetic field with controllable direction and intensity to a rigid sheet initially randomly distributed in liquid photosensitive resin, the sheet can be guided to distribute along the magnetic field direction. Subsequent resin curing permanently fixes its spatial orientation, forming an ordered microstructure. Furthermore, the mechanical shearing action generated by a force field can guide fibers to rotate in a specific direction, thereby generating a microstructure with uniformly aligned rigid components. However, external field-assisted multi-material 3D printing schemes involve the use of high-energy-density external field generators, which are complex to operate and even pose certain risks. Sometimes, the material must also possess external field responsiveness, limiting the types of rigid components that can be used. On the other hand, external fields can generally only be used to adjust the overall spatial orientation of the rigid components, not to independently control the precise position of each rigid component unit, resulting in only a limited degree of ordered arrangement of the rigid components. Therefore, developing more powerful multi-material 3D printing methods to achieve free manipulation of rigid components and the creation of complex microstructures is a pressing technical challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a printing method and apparatus that supports the printing of mixed soft and hard materials, so as to solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A printing method supporting the printing of mixed soft and hard materials, with the following specific steps:

[0006] S1. Prepare raw materials: Place the pre-cut hard thin sheets into the grids of the positioning groove one by one; add a certain amount of photosensitive resin to the resin injector;

[0007] S2. Determine printing parameters: Determine the pick-and-place printhead, determine the coordinates of the pick-and-place printhead to be placed, and plan the movement path of the three-axis moving platform throughout the printing process based on the thickness of the rigid sheet, and write it into code; determine the extrusion pressure and extrusion time based on the viscosity and layer thickness of the photosensitive resin.

[0008] S3. Pre-printing: Print with the pickup-placement printhead and dispensing printhead pressure turned off; observe whether the movement path of the pickup-placement printhead is reasonable during the printing process;

[0009] S4. Formal Printing:

[0010] S401. Use the dispensing printhead to squeeze out an appropriate amount of photosensitive resin liquid onto the surface of a rigid sheet that has already been placed in a certain layer;

[0011] S402. Control the printing table to rotate slowly at a suitable acceleration until it reaches a certain speed and then maintain a constant speed. As the printing table rotates, the droplets gradually seep into the gaps between adjacent sheets and spread evenly on the surface of the sheets to form a liquid film of a certain thickness.

[0012] S403. Control the pick-and-place printhead to move to the positioning slot containing the rigid sheet. When the printhead approaches the center of the rigid sheet from above until it is one millimeter away, stop moving. Apply negative pressure to use suction to pick up the sheet at the end of the printhead and then transfer it to the printing area. Determine the coordinates of the sheet to be placed according to the design requirements of the microstructure. Control the printhead to move to the coordinates until the height difference is one millimeter and stop moving. Apply positive pressure to remove the suction and place the sheet in the designated area. Repeat the pick-and-place operation until all the sheets in the layer are placed.

[0013] S404. Turn on the projector to illuminate the liquid resin on the outermost layer of the printing area, so that the rigid sheet forms a firm bond with the cured soft substrate along with the resin curing.

[0014] S405. After the exposure is completed, the next printing cycle begins. The steps of dispensing, homogenizing, picking up, transferring, placing, and exposing are repeated to achieve high-precision mixing and assembly of soft and hard heterogeneous components in three-dimensional space.

[0015] S406. Run the verified correct code and wait for printing to continue until the end.

[0016] Preferably, the rigid sheet in S1 includes glass, ceramic, and acrylic.

[0017] Preferably, in S2, the pick-and-place printhead is determined based on the placement position of the rigid sheet in the positioning slot; the placement coordinates of the pick-and-place printhead are determined based on the specific position of each sheet in the material domain according to the microstructure pattern to be created, thereby determining the placement coordinates of the pick-and-place printhead.

[0018] Preferably, the thickness of the liquid film in S402 is controlled by the rotation speed.

[0019] A printing apparatus for supporting a printing method of printing mixed soft and hard materials includes a three-axis platform, a projector, a pick-and-place component, and a dispensing printhead.

[0020] Preferably, the three-axis platform specifically includes an optical breadboard with adjustable height, an X-axis moving platform, a Y-axis moving platform, a Z-axis moving platform, an XY-axis moving platform connecting plate, and a horizontal to vertical support.

[0021] The liftable breadboard and the X-axis moving platform are fixed to the optical breadboard with hexagonal bolts. Meanwhile, in order to fix the Y-axis moving platform and the Z-axis moving platform, the XY-axis moving platform connecting plate and the horizontal to vertical bracket are fixed to the X-axis moving platform and the liftable breadboard, respectively.

[0022] Preferably, the pick-and-place component includes

[0023] Pick-up and placement of syringes, detachable syringe clamp, syringe pickup mounting plate, 100mm optical support rod, print table connection plate, 75mm optical support rod, positioning slot mounting plate, positioning slot, brushless motor, brushless motor mounting plate, flange, print barrel connector and print barrel;

[0024] The syringe is inserted into the detachable syringe clamp and secured from the left side with an internal hex nut. The detachable syringe clamp is fixed to the projector and syringe pickup mounting plate. The projector and syringe pickup mounting plate and the Z-axis moving platform can be connected by four 100mm optical support rods. The projector is mounted on the projector and syringe pickup mounting plate. The Y-axis and print station connection plate is fixed on the Y-axis moving platform and four 75mm optical support rods are screwed onto it. The positioning slot mounting plate is secured to the 75mm optical support rods with internal hex bolts through the threaded holes on the side. The positioning slot is placed directly in the slot of the positioning slot mounting plate. The brushless motor is fixed to the brushless motor mounting plate. The brushless motor mounting plate is fixed to the 75mm optical support rods through the reserved holes. The flange is fixed to the brushless motor shaft with a set screw. The print barrel connector and the print barrel are sequentially interference-fitted onto the flange.

[0025] Preferably, the dispensing printhead includes a stepper motor, a stepper motor mounting plate, a 225mm optical support rod, a support column, a coupling, a resin syringe, a syringe clamp, and a horizontal connecting rod;

[0026] The stepper motor is fixed on the stepper motor mounting plate, which is fixed on the optical breadboard by a 225mm optical support rod. The support column is connected to the stepper motor shaft by a coupling. The resin syringe is inserted into the syringe clamp and fixed. The syringe clamp is connected to the support column by a horizontal connecting rod.

[0027] The technical effects and advantages of this invention are as follows: By adjusting the positive and negative air pressure, the rigid sheet can be independently picked up and placed in space. Furthermore, by combining it with dispensing and homogenizing, it can create materials with complex heterogeneous microstructures. The manufacturing method is innovative, which can achieve a more orderly arrangement of rigid components in the material domain. It has a high degree of automation, strong reliability, and is suitable for general materials that do not have external field response capabilities.

[0028] It enables the manufacture of high-performance materials with complex microstructures, in which the distribution and position of hard components in the material domain can be flexibly adjusted as needed. This changes the previous situation where the spatial position of hard components could not be precisely controlled in multi-material 3D printing technology. It is simple to operate, highly reliable, and provides an important guarantee for the development of high-performance materials. Attached Figure Description

[0029] Figure 1 A schematic diagram of a multi-material 3D printing method supporting the assembly of mixed soft and hard heterogeneous components provided by the present invention;

[0030] Figure 2 A schematic diagram of a multi-material 3D printing device that supports the assembly of mixed soft and hard heterogeneous components is provided by the present invention.

[0031] Figure 3A schematic diagram showing the separation of the projection and pick-and-place systems in the multi-material 3D printing apparatus provided by the present invention;

[0032] Figure 4 A schematic diagram showing the separation of the multi-material 3D printing apparatus provided by the present invention, including the pick-and-place and printing table systems;

[0033] Figure 5 The multi-material 3D printing apparatus provided by the present invention includes a schematic diagram of the dispensing system.

[0034] In the diagram: 1. Optical breadboard; 2. Adjustable breadboard; 3. Horizontal to vertical support; 4. X-axis moving platform; 5. XY-axis moving platform connecting plate; 6. Y-axis moving platform; 7. Z-axis moving platform; 8. 100mm optical support rod; 9. Syringe pick-up and placement device; 10. Detachable syringe clamp; 11. Projection and syringe pick-up and placement fixing plate; 12. Projector; 13. Y-axis and print table connecting plate; 14. 75mm optical support rod; 15. Positioning slot fixing plate; 16. Positioning slot; 17. Brushless motor; 18. Brushless motor fixing plate; 19. Flange; 20. Flange and print barrel connector; 21. Print barrel; 22. 225mm optical support rod; 23. Stepper motor; 24. Stepper motor fixing plate; 25. Coupling; 26. Support column; 27. Resin syringe; 28. Syringe clamp; 29. ​​Horizontal connecting rod. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] This invention provides a printing method and apparatus that supports the printing of mixed soft and hard materials, as shown in the figure. The technical solution provided by this invention is as follows:

[0037] For a typical printing cycle, such as Figure 1As shown, this involves six key operations. First, a suitable amount of photosensitive resin droplets are extruded from the dispensing printhead onto the surface of a rigid sheet that has already been layered. Then, the print stage is controlled to rotate slowly at a suitable acceleration until it reaches a certain speed and then maintains a constant rotation. As the print stage rotates, the droplets gradually seep into the gaps between adjacent sheets and spread evenly on the sheet surface to form a liquid film of a certain thickness. The thickness of the liquid film is controlled by the rotation speed. Next, the pick-and-place printhead is controlled to move to the positioning slot containing the rigid sheet. The printhead stops when it approaches the center of the rigid sheet from above and is within one millimeter of the center. To stop the movement, negative pressure is applied to use suction to pick up the sheet at the end of the print head, and then it is transferred to the printing area. The coordinates of the sheet to be placed are determined according to the design requirements of the microstructure. The print head is controlled to move to these coordinates until the height difference is one millimeter, at which point the movement stops. Positive pressure is applied to remove the suction and place the sheet in the designated area. The pick-up and placement operation is repeated until all sheets of that layer are placed. Next, the projector is turned on to illuminate the liquid resin on the outermost layer of the printing area, so that the rigid sheet forms a strong bond with the cured soft substrate along with the resin curing. After the exposure is completed, the next printing cycle begins, repeating the steps of dispensing, homogenizing, picking, transferring, placing, and exposing. By continuously accumulating rigid sheets and soft substrates in the thickness direction, high-precision mixing and assembly of heterogeneous components in three-dimensional space is achieved, completing the creation of a material with a specific microstructure.

[0038] Based on the above printing method, the three-dimensional printing device established by this invention is as follows: Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the printing device consists of an optical metal breadboard 1, a height-adjustable metal breadboard 2, a horizontal-to-vertical support 3, an X-axis moving platform 4, an XY-axis moving platform connecting plate 5, a Y-axis moving platform 6, a Z-axis moving platform 7, a 100mm optical support rod 8, a positive and negative pressure adjustable pick-up and place syringe 9, a detachable syringe clamp 10, a projection and pick-up and place syringe fixing plate 11, a projector with exposure function 12, a Y-axis and printing table connecting plate 13, a 75mm optical support rod 14, a positioning groove fixing plate 15, a positioning groove 16, a brushless motor 17, a brushless motor fixing plate 18, a flange 19, a flange and printing barrel connector 20, a printing barrel 21, a 225mm optical support rod 22, a stepper motor 23, a stepper motor fixing plate 24, a coupling 25, a support column 26, a photosensitive resin syringe 27, a syringe clamp 28, and a horizontal connecting rod 29. The printing barrel 21, the positioning groove fixing plate 15, and the positioning groove 16 are made of aluminum alloy, while the other customized parts are made of acrylic sheet.

[0039] Optical breadboard 1 is fixed to the optical platform. The height-adjustable breadboard 2 and the X-axis moving platform 4 are fixed to the optical breadboard 1 using hex bolts. Simultaneously, to fix the Y-axis moving platform 6 and the Z-axis moving platform 7, XY-axis moving platform connecting plates 5 and horizontal-to-vertical brackets 3 are fixed to the X-axis moving platform 4 and the height-adjustable breadboard 2 respectively. The three-axis platform is now installed. Next, the projection and pick-and-place components are installed. The pick-and-place syringe 9 is inserted into the detachable syringe clamp 10 and secured from the left side with an hex nut. The detachable syringe clamp 10 is fixed to the projection and pick-and-place syringe fixing plate 11 (with pre-drilled holes to adjust the height of the pick-and-place device). The projection and pick-and-place syringe fixing plate 11 and the Z-axis moving platform 7 can be connected via four 100mm optical support rods 8. After this, the projector 12 is installed on the projection and pick-and-place syringe fixing plate 11 (incorrect sequence will result in installation failure of the projector 12). To facilitate the installation of the brushless motor 17, the Y-axis and print station connection plate 13 is fixed on the Y-axis moving platform 6, and four 75mm optical support rods 14 are screwed onto it. The positioning slot fixing plate 15 is secured to the 75mm optical support rods 14 through the threaded holes on the side with hex bolts. The positioning slot 16 is placed directly in the slot of the positioning slot fixing plate 15. The brushless motor 17 (which controls the flatness and thickness of each layer of resin by different speeds and accelerations) is fixed on the brushless motor fixing plate 18. The brushless motor fixing plate 18 is fixed to the 75mm optical support rods 14 through the reserved holes. To horizontally fix the print barrel, a flange 19 is added, which is fixed to the shaft of the brushless motor 17 by set screws. The flange, print barrel connector 20, and print barrel 21 are sequentially interference-fitted onto the flange 19 (to facilitate the removal of printed parts and cleaning of the print barrel after printing). The pickup stage and print station are now installed. Finally, install the dispensing printhead. Since the pick-and-place operation takes up most of the time during printing, a stepper motor should be used to control the printhead away from the working area when it is idle to prevent it from interfering with the pick-and-place operation. Stepper motor 23 is fixed to stepper motor mounting plate 24, which is fixed to optical breadboard 1 via a 225mm optical support rod 22. Support column 26 is connected to the shaft of stepper motor 23 via coupling 25. Similarly, resin syringe 27 is inserted into syringe clamp 28 and fixed, which is connected to support column 26 via horizontal connecting rod 29. The above three-axis moving platform and projector 12 are directly connected to the computer and controlled by code. Brushless motor 17 and stepper motor 23 are connected to the computer via a microcontroller as a lower-level device. The air channels of pick-and-place syringe 9 and resin syringe 27 are connected to a high-precision dispensing machine (not shown in the figure). The dispensing machine applies positive or negative pressure, and it is also connected and controlled by a microcontroller as a lower-level device.

[0040] The specific operating procedure for this printing device is as follows:

[0041] Step 101, Prepare raw materials: Place the pre-cut hard thin sheets (glass, ceramic and acrylic, etc.) into the grids in the positioning groove 16 one by one, and then embed the entire positioning groove 16 into the positioning groove fixing plate 15; then add a certain amount of photosensitive resin to the resin injector 27, and insert the injector into the syringe clamp 28 to fix it.

[0042] Step 102, determine printing parameters: determine the coordinates to be picked up by the pick-and-place printhead based on the placement position of the rigid sheet in the positioning groove 16, determine the specific position of each sheet in the material domain based on the microstructure style to be created, and then determine the placement coordinates of the pick-and-place printhead. Combined with the thickness of the rigid sheet, plan the movement path of the three-axis moving platform in the whole printing process and write it into code; determine the appropriate extrusion pressure and extrusion time based on the viscosity and layer thickness of the photosensitive resin.

[0043] Step 103, Pre-printing: Print with the pickup-placement printhead and dispensing printhead pressure turned off. Observe whether the movement path of the pickup-placement printhead is reasonable during the printing process. For example, whether there is pin collision or other situations that should not occur. If so, stop immediately and modify the code until the expected effect is achieved.

[0044] Step 104, Formal Printing: Turn on the pressure of the pickup-place printhead and the dispensing printhead, run the verified correct code, and wait for printing to continue until it ends. During this period, pay close attention to whether the printing ink is used up, and replace it in time if necessary.

[0045] Step 105, complete printing: Remove the print barrel 21 from the print barrel connector 20, remove the component from the print table with a blade, and clean the residual resin and the table with alcohol.

[0046] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A printing method supporting the printing of mixed soft and hard materials, characterized in that: The specific steps are as follows: S1. Prepare raw materials: Place the pre-cut hard thin sheets into the grids of the positioning groove one by one; add a certain amount of photosensitive resin to the resin injector; S2. Determine printing parameters: Determine the pick-and-place printhead, determine the coordinates of the pick-and-place printhead to be placed, and plan the movement path of the three-axis moving platform throughout the printing process based on the thickness of the rigid sheet, and write it into code; determine the extrusion pressure and extrusion time based on the viscosity and layer thickness of the photosensitive resin. S3, Pre-printing: Printing is performed with the pickup-placement printhead and dispensing printhead pressure turned off; Observe whether the movement path of the pick-up and place-printhead during the printing process is reasonable; S4. Formal Printing: S401. Use the dispensing printhead to squeeze out an appropriate amount of photosensitive resin liquid onto the surface of a rigid sheet that has already been placed in a certain layer; S402. Control the printing table to rotate slowly at a suitable acceleration until it reaches a certain speed and then maintain a constant speed. As the printing table rotates, the droplets gradually seep into the gaps between adjacent sheets and spread evenly on the surface of the sheets to form a liquid film of a certain thickness. S403. Control the pick-and-place printhead to move to the positioning slot containing the rigid sheet. When the printhead approaches the center of the rigid sheet from above until it is one millimeter away, stop moving. Apply negative pressure to use suction to pick up the sheet at the end of the printhead and then transfer it to the printing area. Determine the coordinates of the sheet to be placed according to the design requirements of the microstructure. Control the printhead to move to the coordinates until the height difference is one millimeter and stop moving. Apply positive pressure to remove the suction and place the sheet in the designated area. Repeat the pick-and-place operation until all the sheets in the layer are placed. S404. Turn on the projector to illuminate the liquid resin on the outermost layer of the printing area, so that the rigid sheet forms a firm bond with the cured soft substrate along with the resin curing. S405. After the exposure is completed, the next printing cycle begins. The steps of dispensing, homogenizing, picking up, transferring, placing, and exposing are repeated to achieve high-precision mixing and assembly of soft and hard heterogeneous components in three-dimensional space. S406. Run the verified correct code and wait for printing to continue until the end.

2. The printing method supporting the printing of mixed soft and hard materials according to claim 1, characterized in that: The rigid sheets in S1 include glass, ceramic, and acrylic.

3. The printing method supporting the printing of mixed soft and hard materials according to claim 1, characterized in that: In S2, the pick-and-place printhead is determined based on the placement position of the rigid sheet in the positioning slot; the placement coordinates of the pick-and-place printhead are determined based on the specific position of each sheet in the material domain according to the microstructure pattern to be created, thereby determining the placement coordinates of the pick-and-place printhead.

4. The printing method supporting the printing of mixed soft and hard materials according to claim 1, characterized in that: The thickness of the liquid film in S402 is controlled by the rotation speed.

5. A printing method supporting the printing of mixed soft and hard materials according to claim 1, characterized in that: The printing apparatus for running the method includes a three-axis platform, a projector, a pick-and-place unit, and a dispensing printhead.

6. A printing method supporting the printing of mixed soft and hard materials according to claim 5, characterized in that: The three-axis platform specifically includes an optical breadboard with adjustable height, an X-axis moving platform, a Y-axis moving platform, a Z-axis moving platform, an XY-axis moving platform connecting plate, and a horizontal to vertical support. The liftable breadboard and the X-axis moving platform are fixed to the optical breadboard with hexagonal bolts. Meanwhile, in order to fix the Y-axis moving platform and the Z-axis moving platform, the XY-axis moving platform connecting plate and the horizontal to vertical bracket are fixed to the X-axis moving platform and the liftable breadboard, respectively.

7. A printing method supporting the printing of mixed soft and hard materials according to claim 6, characterized in that: The pick-and-place component includes Pick-up and placement of syringes, detachable syringe clamp, syringe pickup mounting plate, 100mm optical support rod, print table connection plate, 75mm optical support rod, positioning slot mounting plate, positioning slot, brushless motor, brushless motor mounting plate, flange, print barrel connector and print barrel; The syringe is inserted into the detachable syringe clamp and secured from the left side with an internal hex nut. The detachable syringe clamp is fixed to the projector and syringe pickup mounting plate. The projector and syringe pickup mounting plate and the Z-axis moving platform are connected by four 100mm optical support rods. The projector is mounted on the projector and syringe pickup mounting plate. The Y-axis and print station connection plate is fixed on the Y-axis moving platform and four 75mm optical support rods are screwed onto it. The positioning slot mounting plate is secured to the 75mm optical support rods with internal hex bolts through the threaded holes on the side. The positioning slot is placed directly in the slot of the positioning slot mounting plate. The brushless motor is fixed to the brushless motor mounting plate. The brushless motor mounting plate is fixed to the 75mm optical support rods through the reserved holes. The flange is fixed to the brushless motor shaft with set screws. The print barrel connector and the print barrel are sequentially interference-fitted onto the flange.

8. A printing method supporting the printing of mixed soft and hard materials according to claim 7, characterized in that: The dispensing printhead includes a stepper motor, a stepper motor mounting plate, a 225mm optical support rod, a support column, a coupling, a resin syringe, a syringe clamp, and a horizontal connecting rod. The stepper motor is fixed on the stepper motor mounting plate, which is fixed on the optical breadboard by a 225mm optical support rod. The support column is connected to the stepper motor shaft by a coupling. The resin syringe is inserted into the syringe clamp and fixed. The syringe clamp is connected to the support column by a horizontal connecting rod.

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