A composition for 3D printing, a 3D printing method and device

Abstract

The application discloses a kind of 3D printing composition, 3D printing method and device.3D printing composition is constituted by powder phase and reinforcing liquid. The printing device includes extrusion device and reinforcing device, extrusion device includes for lifting support mechanical property, guaranteeing fiber centering, fiber feeding module, reinforcing device includes the reinforcing liquid container, mist module and control module for reinforcing the support printed, etc. The printing process of the application has no sintering, and the printing material has no polymer. The product has excellent degradability and biocompatibility. Directly printing clinical real-time bioceramic materials by combining controllable self-reinforcement process control, the shorter real-time reinforcement time can be adjusted in the printing process according to the implant site.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, specifically to a 3D printing composition, a 3D printing method, and an apparatus. Background Technology

[0002] Bioceramics refer to a class of ceramic materials used for specific biological or physiological functions, that is, ceramic materials used directly in or related to the human body in biological, medical, and biochemical applications. Currently, bioceramic materials represented by hydroxyapatite (HA), tricalcium phosphate (TCP), and bioactive glass (BG) are the most widely used.

[0003] Currently, there are no reports of 3D printing technologies and processes that do not use polymer binders or undergo high-temperature post-treatment. Polymers can affect the biodegradability of scaffolds, and after implantation, they can produce acidic substances in the body, affecting the body's acid-base balance. Furthermore, high-temperature sintering processes may damage the chemical composition of the raw materials and prevent the addition of cell-activating factors and bioactive substances, thus hindering the healing of bone defects. Simultaneously, 3D-printed bioceramic scaffolds cannot meet the requirements of direct printing and adjustment of the scaffold structure and shape based on the actual implantation site in real-time clinical surgery, significantly limiting the application of 3D-printed bioceramic scaffolds. Moreover, 3D-printed calcium-phosphorus ceramic-based bone scaffolds generally require sintering in a high-temperature furnace for 16-32 hours or freeze-drying in a fume hood for 1 hour, and integrated, one-piece 3D-printed bioceramic scaffolds are lacking.

[0004] Furthermore, current research on continuous fiber-reinforced ceramic 3D printing technology is limited and still in the development stage, presenting numerous challenges. For instance, existing technologies struggle to deliver fibers precisely, continuously, and stably. The fibers delivered are often large bundles (1000 mm in diameter), typically requiring right-angle bends on a horizontal plane via a gantry module structure. Due to the inherent toughness of continuous fiber materials, significant friction occurs with the nozzle, causing the fiber to stop feeding or become distributing poorly to one side of the coating material. This results in poor centering, and the ceramic matrix material cannot fully penetrate the fiber filaments, failing to bond them together and creating voids within the printing support. This severely reduces the support's mechanical properties, leading to defects in the 3D printed product. Moreover, feeding tiny, micron-sized, lightweight, and soft single fibers (0.15 mm–0.25 mm) into viscous slurries is particularly problematic, as maintaining fiber tension and verticality is difficult. Additionally, current technologies typically use external motors as a power source, which cannot guarantee the stability of fiber delivery. Summary of the Invention

[0005] The purpose of this invention is to provide a 3D printing composition, a 3D printing apparatus, and an application to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A first aspect of the present invention provides a composition for 3D printing, the composition comprising a powder phase and a strengthening liquid;

[0008] The powder phase includes hydroxyapatite, β-tricalcium phosphate and calcium dihydrogen phosphate monohydrate, and the mass ratio of hydroxyapatite, β-tricalcium phosphate and calcium dihydrogen phosphate monohydrate is 20-30:11:9.

[0009] The strengthening solution comprises citric acid monohydrate and glycerol, and the ratio of citric acid monohydrate to glycerol is 15:8, expressed in mmol / g.

[0010] Furthermore, the concentration of the citric acid monohydrate is 1.4–1.6 mol / L.

[0011] Furthermore, the preparation method of the strengthening liquid includes: adding glycerol to a hydrated citric acid solution to prepare the strengthening liquid.

[0012] Furthermore, the 3D printing composition is prepared by mixing the powder phase and the strengthening liquid in a ratio of 14:10, based on g / mL.

[0013] A second aspect of the present invention provides a 3D printing method, comprising the following steps:

[0014] Obtain data for at least one printed layer of a 3D object;

[0015] According to the printing data of each layer, the composition of any one of claims 1 to 3 is sprayed to form a material layer;

[0016] Based on the layer printing data, at least one printing layer is obtained by stacking layers one by one, and the 3D printed product is obtained.

[0017] Furthermore, the layer printing data includes the printing path, printing layer thickness, and printing spacing, with the moving speed controlled at 150mm / min to 200mm / min, and the slurry extrusion diameter ranging from 0.8mm to 1.6mm depending on the nozzle diameter.

[0018] Furthermore, the 3D printed product is subjected to a strengthening treatment, which involves atomizing the 3D printed product with the strengthening liquid for 2 to 24 hours.

[0019] A third aspect of the present invention provides an apparatus for implementing any of the methods described above, the apparatus comprising an extrusion device, a filament feeding device, a reinforcing device, and a fixing device;

[0020] The extrusion device includes a power unit connected to a storage container, an external nozzle connected to the lower end of the storage container, and a nozzle connected to a spray nozzle.

[0021] The fiber feeding device includes a fiber guide tube, the lower end of which is connected to an inner nozzle, and the inner nozzle is connected to a nozzle.

[0022] The enhancement device includes a power switch, which is connected to a motor assembly. The motor assembly is connected to a liquid level detector and an atomizer. The upper end of the atomizer is connected to a mist outlet, and the lower end of the atomizer is connected to a liquid inlet.

[0023] The fixing device includes a slide rail, and the slide rail is connected to a fixing block.

[0024] Furthermore, the power unit is an air pump device, which includes an air pump pipe and an air pump, and the pressure of the air pump is 0.2MPa to 0.5MPa; a fiber bundle feeding device is provided inside the inner nozzle; and the liquid level detector is connected to an alarm.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] (1) The bioceramic slurry formulation of the present invention has developed a 3D printing technology for bioceramics for the first time without adding a polymer binder at room temperature. This 3D printing technology can obtain a bioceramic scaffold with excellent mechanical properties without post-processing. At the same time, the scaffold has excellent degradability because it has not undergone high-temperature post-processing.

[0027] (2) The 3D printing device of the present invention can perform real-time strengthening, and the short real-time strengthening time allows the surgeon to make timely and flexible adjustments according to the implantation site during the printing process. The application of the 3D printing device of the present invention can directly print and adjust the structure and shape of the scaffold according to the actual implantation site structural size requirements of the patient in the clinical surgical scene, and has great application prospects.

[0028] (3) The 3D printing device described in this invention is not limited to a single filament or a bundle of continuous fiber reinforcement devices. It uses the flow of slurry as a driving force to regulate the synchronous feeding of fibers and slurry, ensuring the feeding stability and centering of fibers, which can further improve the printing performance and mechanical properties of bone scaffolds.

[0029] (4) The bioceramic material printed by the 3D printing device of the present invention does not require post-processing and can obtain a bioceramic scaffold with excellent mechanical properties (5.28MPa±0.629MPa). Furthermore, the compressive strength of the scaffold obtained by this technology can meet the requirements of cancellous bone (2-12MPa for cancellous bone), which is 3961.5% higher than that of sintering at 1050℃ (0.13MPa) and 371.4% higher than that of freeze-drying without sintering post-processing (1.12±0.05MPa).

[0030] (5) The mechanical properties and degradability of the prepared bioceramic scaffold can be controlled by adjusting the process (different ratios, different printing spacing, different printing diameters). This innovative 3D printing device and process create favorable conditions for the subsequent printing of bioceramic scaffolds with added cell growth factors and bioactive substances, and provide an important theoretical basis and practical significance for the use of bioceramic scaffolds in bone tissue engineering to replace and repair bone defects. Attached Figure Description

[0031] Figure 1 This is an overall view of the extrusion device and the reinforcing device of a 3D printing apparatus provided in an embodiment of the present invention.

[0032] Figure 2 This is an overall diagram of the reinforcement device of a 3D printing apparatus provided in an embodiment of the present invention.

[0033] Figure 3 This is an overall diagram of the fogging module of the strengthening device of a 3D printing apparatus provided in an embodiment of the present invention.

[0034] Figure 4 This is a diagram of the inner and outer nozzles of the extrusion device of a 3D printing apparatus provided in an embodiment of the present invention.

[0035] Figure 5 This is an overall view of the nozzle inside the extrusion device of a 3D printing apparatus provided in an embodiment of the present invention.

[0036] Figure 6 This is an enlarged view of the inside of the nozzle of the extrusion device of a 3D printing apparatus provided in an embodiment of the present invention.

[0037] Figure 7 A schematic diagram of the transmission and feeding principle of a continuous micron fiber composite material in a 3D printing extrusion device provided in an embodiment of the present invention (F - traction force of slurry on fiber).

[0038] Figure 8 A schematic diagram of the transmission and feeding principle of a continuous micron fiber composite material in a 3D printing extrusion device provided in an embodiment of the present invention (F - traction force of slurry on fiber).

[0039] Figure 9This is an external view of the 3D-printed bracket provided in Embodiment 1 of the present invention.

[0040] Figure 10 This is an external view of the 3D-printed bracket provided in Embodiment 2 of the present invention.

[0041] Figure 11 This is an external view of the 3D-printed bracket provided in Comparative Example 1 of the present invention.

[0042] Figure 12 This is an external view of the 3D-printed bracket provided in Comparative Example 2 of the present invention.

[0043] Figure 13 Compression strength diagrams of 3D printed brackets provided in embodiments and comparative examples of the present invention.

[0044] Figure 14 The degradation curves of the 3D printed scaffolds provided in Embodiments 1 and 2 of the present invention are shown.

[0045] Figure 15 The degradation curve of the 3D printed scaffold provided in Comparative Example 1 of the present invention is shown.

[0046] In the attached diagram: 1. Air pump hose; 2. Air pump connector; 3. Material cylinder sealing cover; 4. Sealing ring; 5. Fiber storage roller; 6. Spring block; 7. Reinforcing tube; 8. Tube plug; 9. Reinforcing liquid; 10. Ultrasonic atomizer; 11. Printing table; 12. Flange bolt; 13. Gasket; 14. Lower end cover of outer nozzle; 15. Lower end cover of inner nozzle; 16. Fiber roller; 17. Large gear; 18. Nozzle; 19. Reverse gear; 20. Inner gear; 21. Small gear; 22. Forward gear; 23. Pin; 24. Upper end cover of inner nozzle; 25. Lower end cover of outer nozzle. 26. End cap; 27. Fiber guide tube; 28. Microporous plunger; 29. ​​Volumetric feed cylinder; 30. Slide rail; 31. Fixing block; 32. Spring; 33. Positioning pin; 34. Fan wheel; 35. Liquid inlet; 36. Liquid level detector; 37. Mist outlet; 38. Liquid outlet; 39. Switch knob; 40. Motor assembly; 41. Base; 42. Screw; 43. Wire; 44. Ultrasonic atomizer holder; 45. Base screw; 46. Switch holder; 47. Liquid inlet tank; 48. Heat dissipation vent; 49. Enhanced liquid container; 40. Control component. Detailed Implementation

[0047] 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.

[0048] Please see Figures 1 to 8 The present invention provides a technical solution:

[0049] A 3D printing apparatus includes an extrusion device, a filament feeding device, a reinforcing device, and a fixing device.

[0050] The extrusion device includes an air pump pipe 1, an air pump connector 2, a barrel sealing cap 3, a sealing ring 4, a constant volume barrel 28, a microporous plunger 27, external nozzles 14 and 25, and a nozzle 18. The lower end of the air pump pipe 1 is connected to the air pump connector 2, and the upper end is connected to the air pump. The lower end of the air pump connector 2 is connected to the barrel sealing cap 3, which has a sealing ring 4 to ensure that the barrel sealing cap 3, when screwed into the constant volume barrel 28, does not leak air when subjected to air pressure. The external nozzles 14 and 25 are divided into upper and lower parts. The upper end 25 of the upper part is designed with external threads to connect to the constant volume barrel 28, and the lower end 14 of the lower part is designed with external threads to connect to the nozzle 18. The lower end of the upper part is embedded into the upper part, and the two parts are positioned by two locating pins 32 on the protruding part and secured by two flange bolts 12 to ensure the seal of the nozzle 18.

[0051] The fiber feeding device comprises a fiber storage roller 5, a spring block 6, a spring 31, a fiber guide tube 26, and inner nozzles 15 and 24. When the microporous plunger 27 passes through the fiber storage section, the spring block 6 and spring 31 retract into the volumetric feed cylinder 28, without affecting the downward pressure of the microporous plunger 27. After the fiber is wound around the fiber in the fiber storage roller 5, it is placed in the groove of the spring block 6, and the spring block 6 and spring 31 pop out, ensuring that the fiber storage roller 5 only rotates axially. An air pump is connected to the volumetric feed cylinder 28, and the fiber guide tube 26 is installed below the volumetric feed cylinder 28. The inner nozzles 15 and 24 are connected below the fiber guide tube 26, and the outer nozzles 14 and 25 are connected below the volumetric feed cylinder 28. A fiber bundle feeding device is installed inside the inner nozzle, and a nozzle 18 is connected below the outer nozzles 14 and 25. The flow of the slurry drives the fan wheel 33 to rotate. When the fan wheel rotates clockwise, it drives the internal pinion 21 to rotate clockwise. The pinion 21 drives the forward wheel 22 to rotate counterclockwise. At this time, the inner wheel 20 is stuck, and then the inner wheel 20 rotates counterclockwise along with the forward wheel 22, which in turn drives the large gear 17 to rotate clockwise, thereby driving the fiber roller 16 to rotate clockwise. At this time, the forward wheel 22 drives the reverse wheel 19, but because the inner wheel 20 in the reverse wheel 19 is installed in the opposite order to that in the forward wheel 22, the inner wheel 20 in the reverse wheel 19 will slip. When the fan wheel 33 rotates counterclockwise, it drives the internal pinion 21 to rotate counterclockwise. The pinion 21 then drives the forward wheel 22 to rotate clockwise. At this time, the inner wheel 20 slips. Simultaneously, the forward wheel 22 drives the reverse wheel 19 to rotate counterclockwise, causing the inner wheel 20 to be stuck. Consequently, the inner wheel 20 rotates along with the reverse wheel 19, driving the large gear 17 to rotate clockwise, which in turn drives the fiber roller 16 to rotate clockwise. The simultaneous clockwise rotation of the two fiber rollers 16 drives the fiber bundle to feed downwards, thus completing the fiber bundle feeding motion.

[0052] The strengthening device includes a switch knob 38, a motor assembly 39, a liquid inlet 34, a liquid level detector 35, a mist outlet 36, a liquid outlet 37, an ultrasonic atomizer 10, strengthening liquid 9, a tube plug 8, and a strengthening tube 7. The strengthening tube 7 is a retractable flexible tube. When printing the support, the strengthening liquid 9 is poured in through the liquid outlet 37, and the switch knob 38 is turned on. The strengthening liquid 9 flows from the liquid inlet 34 to the ultrasonic atomizer 10, where it is atomized into fine water molecules. These molecules are then sprayed through the strengthening tube 7 onto the support being printed, causing the support to self-strengthen. When the strengthening liquid level drops to the liquid level detector 35, the device sounds an alarm. At this point, more strengthening liquid 9 is added.

[0053] The fixing device includes the 3D printer's slide rail 29 and the fixing block 30. The fixing block 30 is mounted on the 3D printer's slide rail by screws. The reinforcing tube 7 and the volumetric material cylinder 28 are installed in the two round holes of the fixing block to ensure the stability of the reinforcing tube 7 and the volumetric material cylinder 28 during printing.

[0054] An apparatus and process for 3D printing a bioceramic scaffold, comprising the following steps:

[0055] Step 1: Weigh out a certain mass ratio of HA, β-TCP and Ca(H2PO4)2·H2O powder, and grind and mix them in a mortar.

[0056] Step 2: Prepare a C6H8O7·H2O solution of a certain concentration, then weigh C3H8O3, mix C3H8O3 with the C6H8O7·H2O solution evenly to prepare the strengthening solution 9.

[0057] Step 3: Mix the powder and liquid phases at a certain solid-liquid ratio, and ultrasonically stir for 3 to 10 minutes to make them evenly mixed and prepare a slurry.

[0058] Step 4: Construct a 3D model based on the desired printed structure, create a 3D digital model of the structure and slice it, set the printing path, printing layer thickness and printing spacing, control the moving speed to 150mm / min~200mm / min, and adjust the slurry extrusion diameter to 0.6mm~1.2mm depending on the nozzle diameter. Connect the computer as the signal control source to the 3D printer and perform debugging.

[0059] Step 5: Insert the volumetric material cylinder 28 into the fixing block 30, and connect the lower end to the inner nozzles 15 and 24 and the outer nozzles 14 and 25. Connect the lower end of the nozzle to the nozzle 18.

[0060] Step 6: The prepared calcium phosphate bioceramic slurry is loaded into the material cylinder. The microporous plunger 27 is pushed through the fiber guide tube 26 with a long needle to compact the slurry in the constant volume material cylinder 28. Then, the fiber storage roller 5 is pressed into the spring block 6. The material cylinder sealing cover 3 is connected above the constant volume material cylinder 28, the air pipe connector 2 is connected, the air pump pipe 1 is connected, and finally the air pump is connected to use the pressure of the air pump as the power source.

[0061] Step 7: Adjust the distance between the nozzle 18 and the printing table 11, insert the reinforcing tube 7 into the fixing block 30, turn on the air pump, adjust the pressure to 0.2MPa~0.5MPa, pour the reinforcing liquid 9 into the pouring port 37, turn on the switch knob 38, adjust the mist output, and the reinforcing liquid 9 reaches the ultrasonic atomizer 10 from the inlet 34, atomizes into fine water molecules, and is then sprayed onto the printable support through the reinforcing tube 7, making the support self-reinforcing.

[0062] Step 8: Turn off the printer and allow the printed bioceramic scaffold to continue strengthening for 2 to 24 hours to complete the scaffold preparation.

[0063] Example 1

[0064] This embodiment provides a 3D printing method for bioceramic scaffolds.

[0065] Step 1: Weigh out HA, β-TCP and Ca(H2PO4)2·H2O powder in a mass ratio of 30:11:9, and grind and mix them in a mortar.

[0066] Step 2: Prepare a 1.4 mol / L C6H8O7·H2O solution. Measure 10 mL of the solution and weigh 7.46 g of C3H8O3. Mix the C3H8O3 and C6H8O7·H2O solution evenly to prepare the strengthening solution.

[0067] Step 3: Mix the powder and liquid phase at a solid-liquid ratio of 1.4 g / mL, and ultrasonically stir for 3 minutes to make them evenly mixed and prepare a slurry.

[0068] Step 4: Construct a 3D model based on the desired printed structure, create a 3D digital model of the structure and slice it, set the printing path, set the printing layer thickness to 0.5mm, the printing spacing to 2mm, control the moving speed to 150mm / min, and the slurry extrusion diameter to 0.8mm. Connect the computer as the signal control source to the 3D printer and perform debugging.

[0069] Step 5: Insert the volumetric material cylinder 28 into the fixing block 30, and connect the lower end to the external nozzles 14 and 25. Connect the lower end of the nozzles to the nozzle 18.

[0070] Step 6: The prepared slurry is loaded into the volumetric hopper 28. The slurry is compacted in the hopper by pushing the plunger with a long needle. The hopper sealing cap 3 is connected above the volumetric hopper 28. Finally, the air pump is connected, and the pressure of the air pump is used as the power source.

[0071] Step 7: Adjust the distance between the nozzle 18 and the printing table 11, insert the reinforcing tube 7 into the fixing block 30, turn on the 3D printer, turn on the air pump, adjust the pressure to 0.2MPa, turn on the switch knob of the reinforcing device, adjust the mist output to 50mL / h, and start the printing operation.

[0072] Step 8: Turn off the printer, keep the intensifier on, and atomize the printed bioceramic scaffold for 24 hours to complete the scaffold preparation.

[0073] Figure 9 The image shows the appearance of the bioceramic scaffold prepared under the above printing conditions. The compressive strength of the obtained bioceramic scaffold is 3.61 ± 0.194 MPa. Figure 14 The degradation curve of the bioceramic scaffold prepared under the above printing conditions showed a weight loss rate of 10.9% after 7 days.

[0074] Example 2

[0075] This embodiment provides a 3D printing method for bioceramic scaffolds.

[0076] Step 1: Weigh out HA, β-TCP and Ca(H2PO4)2·H2O powder in a mass ratio of 20:11:9, and grind and mix them in a mortar.

[0077] Step 2: Prepare a 1.5 mol / L C6H8O7·H2O solution. Measure 10 mL of the solution and weigh 8 g of C3H8O3. Mix the C3H8O3 and C6H8O7·H2O solution evenly to prepare the strengthening solution.

[0078] Step 3: Mix the powder and liquid phase at a solid-liquid ratio of 1.4 g / mL, and ultrasonically stir for 8 minutes to make them evenly mixed and prepare a slurry.

[0079] Step 4: Construct a 3D model based on the desired printed structure, create a 3D digital model of the structure and slice it, set the printing path, set the printing layer thickness to 0.5mm, the printing spacing to 2mm, control the moving speed to 170mm / min, and the slurry extrusion diameter to 1.0mm. Connect the computer as the signal control source to the 3D printer and perform debugging.

[0080] Step 5: Insert the volumetric material cylinder 28 into the fixing block 30, and connect the lower end to the external nozzles 14 and 25. Connect the lower end of the nozzles to the nozzle 18.

[0081] Step 6: The prepared slurry is loaded into the volumetric hopper 28. The slurry is compacted in the hopper by pushing the plunger with a long needle. The hopper sealing cap 3 is connected above the volumetric hopper 28. Finally, the air pump is connected, and the pressure of the air pump is used as the power source.

[0082] Step 7: Adjust the distance between the nozzle 18 and the printing table 11, insert the reinforcing tube 7 into the fixing block 30, turn on the 3D printer, turn on the air pump, adjust the pressure to 0.3MPa, turn on the switch knob of the reinforcing device, adjust the mist output to 50mL / h, and start the printing operation.

[0083] Step 8: Turn off the printer, keep the intensifier on, and atomize the printed bioceramic scaffold for 14 hours to complete the scaffold preparation.

[0084] Figure 10The image shows the appearance of the bioceramic scaffold prepared under the above printing conditions. The compressive strength of the obtained bioceramic scaffold is 5.28±0.629MPa, which is 3961.5% higher than that of the bioceramic scaffold obtained by sintering at 1050℃ (0.13MPa) (X.Li,Y.Yuan,L.Liu,Y.-S.Leung,Y.Chen,Y.Guo,Y.Chai,Y.,Chen 3D printing of hydroxyapatite / tricalcium phosphate scaffold with hierarchical porous structure for bone regeneration[J].Bio-Design and Manufacturing,2019,3(1):15-29.). Compared with the bioceramic scaffold without sintering freeze-drying treatment (1.12±0.05MPa) (S.Eshraghi,S.Das,Micromechanical finite-element modeling andexperimental characterization of the compressive mechanical properties of polycaprolactone–hydroxyapatite composite). Scaffolds prepared by selective laser sintering for bone tissue engineering[J]. Acta Biomaterialia, 2012, 8(8):3138-3143.), with a compressive strength increase of 371.4%. Figure 13 It can be seen that the compressive strength of the bioceramic scaffold prepared under the above conditions is significantly higher than that of the bioceramic scaffold prepared under other parameter conditions. Figure 14 The degradation curve of the bioceramic scaffold prepared under the above printing conditions showed a weight loss rate of 14.7% after 7 days.

[0085] Example 3

[0086] This embodiment provides a 3D printing method for bioceramic scaffolds.

[0087] Step 1: Weigh out HA, β-TCP and Ca(H2PO4)2·H2O powder in a mass ratio of 25:11:9, and grind and mix them in a mortar.

[0088] Step 2: Prepare a 1.6 mol / L C6H8O7·H2O solution. Measure 10 mL of the solution and weigh 8.53 g of C3H8O3. Mix the C3H8O3 and C6H8O7·H2O solution evenly to prepare the strengthening solution.

[0089] Step 3: Mix the powder and liquid phase at a solid-liquid ratio of 1.4 g / mL, and ultrasonically stir for 10 min to make them evenly mixed and prepare a slurry.

[0090] Step 4: Construct a 3D model based on the desired printed structure, create a 3D digital model of the structure and slice it, set the printing path, set the printing layer thickness to 0.5mm, the printing spacing to 2mm, control the moving speed to 200mm / min, and the slurry extrusion diameter to 1.6mm. Connect the computer as the signal control source to the 3D printer and perform debugging.

[0091] Step 5: Insert the volumetric material cylinder 28 into the fixing block 30, and connect the lower end to the external nozzles 14 and 25. Connect the lower end of the nozzles to the nozzle 18.

[0092] Step 6: The prepared slurry is loaded into the volumetric hopper 28. The slurry is compacted in the hopper by pushing the plunger with a long needle. The hopper sealing cap 3 is connected above the volumetric hopper 28. Finally, the air pump is connected, and the pressure of the air pump is used as the power source.

[0093] Step 7: Adjust the distance between the nozzle 18 and the printing table 11, insert the reinforcing tube 7 into the fixing block 30, turn on the 3D printer, turn on the air pump, adjust the pressure to 0.5MPa, turn on the switch knob of the reinforcing device, adjust the mist output to 50mL / h, and start the printing operation.

[0094] Step 8: Turn off the printer, keep the intensifier on, and atomize the printed bioceramic scaffold for 2 hours to complete the scaffold preparation.

[0095] Comparative Example 1

[0096] This comparative example provides a 3D printing method for bioceramic scaffolds.

[0097] The difference between this comparative example and Example 1 is that HA, β-TCP and Ca(H2PO4)2·H2O powders in a mass ratio of 46.6:11:9 were weighed and ground in a mortar. Figure 11 The image shows the appearance of the bioceramic scaffold prepared under the above printing conditions. The compressive strength of the obtained bioceramic scaffold is 0.49 ± 0.169 MPa. Compared with Example 1, the compressive strength decreased by 86.4%. Figure 15 The degradation curve of the bioceramic scaffold prepared under the above printing conditions showed a weight loss rate of 47.6% after 7 days.

[0098] Comparative Example 2

[0099] This comparative example provides a 3D printing method for bioceramic scaffolds.

[0100] The difference between this comparative example and Example 2 is that the printing spacing in step 4 is adjusted to 1mm. Figure 12 The image shows the appearance of the bioceramic scaffold prepared under the above printing conditions. The bioceramic scaffold was tested, and its compressive strength was 3.66 ± 0.949 MPa. Compared to Example 2, the compressive strength increased by 1.3%. While the spacing of the scaffolds decreased with the reduction in printing spacing, the mechanical properties remained relatively similar.

[0101] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0102] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A 3D printing method, characterized in that, The steps include: acquiring at least one printing layer data of the 3D object; The 3D printing composition is sprayed according to the printing data of each layer to form material layers; Based on the layer printing data, at least one printing layer is obtained by stacking layers one by one, and the 3D printed product is obtained. The layer printing data includes the printing path, printing layer thickness and printing spacing, and the moving speed is controlled at 150mm / min to 200mm / min. The extrusion diameter of the 3D printing composition is 0.8mm to 1.6mm. The 3D printed product is then subjected to a strengthening treatment. The strengthening treatment involves atomizing the 3D printed product with the strengthening liquid for 2-24 hours. The 3D printing composition includes a powder phase and a strengthening liquid; The powder phase is composed of hydroxyapatite, β-tricalcium phosphate and calcium dihydrogen phosphate monohydrate, and the mass ratio of hydroxyapatite, β-tricalcium phosphate and calcium dihydrogen phosphate monohydrate is 20~30:11:

9. The strengthening solution is composed of citric acid monohydrate and glycerol, and the ratio of citric acid monohydrate to glycerol is 15:8, calculated in mmol / g. The concentration of the citric acid monohydrate is 1.4~1.6 mol / L; The method for preparing the strengthening solution includes: adding glycerol to a hydrated citric acid solution to prepare the strengthening solution; The 3D printing composition is prepared by mixing the powder phase and the strengthening liquid in a ratio of 14:10, with a weight of g / mL.

2. An apparatus for implementing the method of claim 1, characterized in that, The device includes an extrusion device, a fiber feeding device, a reinforcing device, and a fixing device; the extrusion device includes a power device connected to a storage container, the lower end of which is connected to an external nozzle, which is connected to a nozzle; the fiber feeding device includes a fiber guide tube, the lower end of which is connected to an internal nozzle, which is connected to a nozzle. The enhancement device includes a power switch, which is connected to a motor assembly. The motor assembly is connected to a liquid level detector and an atomizer. The upper end of the atomizer is connected to a mist outlet, and the lower end of the atomizer is connected to a liquid inlet. The fixing device includes a slide rail, and the slide rail is connected to a fixing block; The power unit is an air pump device, which includes an air pump pipe and an air pump. The pressure of the air pump is 0.2MPa~0.5MPa. A fiber bundle feeding device is installed inside the inner nozzle. The liquid level detector is connected to an alarm.

3. The application of a 3D printing method or apparatus in the preparation of bioceramics, characterized in that, The 3D printing method is the 3D printing method according to claim 1, and the apparatus is the apparatus according to claim 2.

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