High-precision thin ink direct writing 3D printing method and device based on temperature control freezing platform

Abstract

The invention relates to the field of ink direct-writing 3D printing methods, in particular to a high-precision thin ink direct-writing 3D printing method and device based on a temperature control freezing platform. The platform comprises a copper plate, a platform top cover, a platform bottom shell, a heat preservation layer, a liquid nitrogen bin, a temperature control heating plate, a digital display temperature control module and a thermocouple temperature measuring device. The method comprises the following steps: building a temperature control freezing platform; a copper plate, a platform top cover, a platform bottom shell, a heat preservation layer, a liquid nitrogen bin, a temperature control heating plate, a digital display temperature control module and a thermocouple temperature measuring device are assembled to form a temperature control freezing platform; preparing a dilute solution raw material; mixing sodium alginate and deionized water according to a certain mass ratio, and stirring; liquid nitrogen is introduced into the built temperature control freezing platform, meanwhile, the temperature control heating plate is started, and the copper plate on the temperature control freezing platform is adjusted to reach a certain temperature; filling the prepared dilute solution into a needle tube of an ink direct-writing 3D printer, and finishing pattern printing on a copper plate on a temperature control freezing platform of which the temperature is set; the used dilute solution is a solution which does not have the shear thinning characteristic, and a printed product pattern is a high-resolution pattern.

Description

Technical Field

[0001] The present invention relates to the field of ink direct writing 3D printing methods, and in particular to a high-precision dilute ink direct writing 3D printing method based on a temperature-controlled freezing platform. Background Art

[0002] The ink direct writing (DIW) 3D printing method uses inkjet printing to build materials layer by layer into three-dimensional objects, which has the advantages of high precision, multi-material printing and complex structure manufacturing. However, the ink traditionally used in the ink direct writing 3D printing method is usually relatively viscous and has certain shear thinning properties, which to a certain extent limits the selection and proportion of ink materials and is not conducive to storage for backup. In addition, the relatively viscous ink has a relatively dense texture and is easy to clog the needle during the ink direct writing 3D printing process, affecting the continuity of the printing process. Therefore, a major challenge for the ink direct writing 3D printing method is to create a method that can complete printing using a dilute solution.

[0003] The dilute solution direct writing 3D printing method based on a temperature-controlled freezing platform can not only realize the printing and molding of dilute solutions, but also provide in-situ directional freezing for aqueous inks that do not have obvious shear thinning properties. The printable aqueous dilute ink is extruded through the needle of the ink direct writing 3D printer under the action of an air pump, and quickly solidifies after contacting a low-temperature copper plate, causing the water in the ink to instantly freeze into ice and continue to grow upward. In the subsequent freeze-drying process, these ice crystals sublimate and form a directional bionic pore structure in situ. This technology greatly improves the fidelity of the ink and the integrity of the printed structure, providing a feasible solution for the design of customized structural materials for 3D printing.

[0004] In order to further realize the direct ink writing 3D printing pattern molding of dilute solutions, the in-situ directional freezing assisted 3D printing method was applied. The currently reported in-situ directional freezing assisted 3D printing method usually places the frozen copper plate directly on the 3D printer stage for model printing. This method is cumbersome to operate and is not conducive to regulating the temperature of the copper plate within a certain range. However, the commercial temperature-controlled freezing platform available on the market, although it can achieve a certain range of temperature control, is expensive and has large dimensions. It is not suitable for laboratory desktop-level ink direct writing 3D printing equipment in terms of economy and practicality.

[0005] Therefore, it is still a challenge to build a temperature-controlled freezing platform that is both economical and practical, realize the in-situ directional freezing-assisted ink direct writing 3D printing method, and apply it to the printing and molding of dilute solutions. Summary of the invention

[0006] The purpose of the present invention is to address the problems existing in the background technology and propose a high-precision dilute ink direct writing 3D printing method based on a temperature-controlled freezing platform; the temperature-controlled freezing platform proposed in the present invention has a novel construction method, a simple process, and a low cost, and can perform ink direct writing 3D printing of high-resolution patterns on dilute solutions that do not have shear-thinning properties, which has important application value for the development of dilute solution printing methods.

[0007] The technical solution of the present invention:

[0008] The first aspect of the present invention provides a temperature-controlled freezing platform device copper plate, platform top cover, platform bottom shell, insulation layer, liquid nitrogen warehouse, temperature-controlled heating plate, digital display temperature control module and thermocouple temperature measuring device, wherein:

[0009] The copper plate is placed in the circular hole on the platform top cover, and the bottom surface of the copper plate is engaged with the flange around the circular hole on the bottom surface of the platform top cover;

[0010] The platform top cover is installed with the platform bottom shell through L-shaped latches at the four corners;

[0011] The insulation layer is filled in the platform bottom shell, and a groove is opened in its central area to carry the liquid nitrogen tank;

[0012] The liquid nitrogen tank is placed in the groove in the central area of ​​the insulation layer;

[0013] The adhesive backing of the temperature-controlled heating plate is bonded to the lower surface of the copper plate;

[0014] The digital display temperature control module is connected to the temperature control heating plate through wires;

[0015] The temperature measuring lead of the thermocouple temperature measuring device is connected to the copper plate; the temperature of the temperature control platform is regulated between -100°C and 0°C.

[0016] Preferably, the copper plate has a diameter of 60 mm and a thickness of 2 mm, has good thermal conductivity, and is used to carry the pattern model printed by the ink direct writing 3D printer.

[0017] Preferably, the temperature-controlled heating plate can achieve precise heating temperature control between 0-100°C through the digital display control module; the temperature-controlled freezing platform can complete the adjustment within a certain temperature range when liquid nitrogen is introduced.

[0018] Preferably, the liquid nitrogen tank is a stainless steel bowl with a truncated cone-shaped appearance, a top opening end diameter of 60 mm, a bottom diameter of 40 mm, a height of 28 mm, and a wall thickness of 1 mm; it is used to carry the liquid nitrogen passed into the temperature-controlled freezing platform to achieve a continuous low-temperature environment in the temperature-controlled freezing platform.

[0019] Preferably, the thermal insulation layer is aluminum silicate thermal insulation cotton, and the thermal insulation layer is filled into the temperature-controlled freezing platform to achieve a continuous low-temperature freezing effect of the temperature-controlled freezing platform.

[0020] Preferably, the platform bottom shell is made of PLA material by 3D printing, and the platform bottom shell is 120 mm long, 75 mm wide, 38 mm high, and 1 mm thick, with a side opening for easy liquid nitrogen input;

[0021] The platform cover is made of PLA material through 3D printing. The platform cover is 120mm long, 75mm wide and 2mm thick. There is a 60mm diameter round hole on the top and a 1mm thick flange around the round hole on the bottom to support the copper plate. L-shaped pins are designed at the four corners of the bottom of the platform cover to realize the installation of the platform cover and the platform bottom shell.

[0022] The second aspect of the present invention provides a high-precision dilute ink direct writing 3D printing method based on a temperature-controlled freezing platform, comprising the following specific steps:

[0023] S1. Build a temperature-controlled freezing platform; assemble the copper plate, platform top cover, platform bottom shell, insulation layer, liquid nitrogen tank, temperature-controlled heating plate, digital display temperature control module and thermocouple temperature measuring device in a certain order to make a temperature-controlled freezing platform;

[0024] S2. Prepare dilute solution raw materials; mix sodium alginate and deionized water in a certain mass ratio and stir;

[0025] S3, introducing liquid nitrogen into the temperature-controlled freezing platform built in step S1, turning on the temperature-controlled heating plate, and adjusting the copper plate on the temperature-controlled freezing platform to a certain temperature;

[0026] S4, the diluted solution prepared in step S2 is loaded into the needle tube of the ink direct writing 3D printer, and the pattern is printed on the copper plate on the temperature-controlled freezing platform whose temperature is adjusted in step S3.

[0027] Preferably, in step S2, sodium alginate and deionized water are mixed in a mass ratio of 50:1, and stirred for 1 to 12 hours using a magnetic stirrer to be fully mixed, or manually ground for 20 minutes to 2 hours, or stirred for 10 minutes to 1 hour using a stirring-degassing machine, and then degassed for 10 minutes to 1 hour.

[0028] Preferably, in step S3, the adhesive backing of the temperature-controlled heating plate is attached to the bottom surface of the copper plate. When a certain amount of liquid nitrogen is introduced and the copper plate reaches a certain low temperature state, the temperature-controlled heating plate is turned on to heat it to a certain temperature. When the indication of the thermocouple temperature measuring device is lower than the target temperature, the introduction of liquid nitrogen is stopped and the temperature of the temperature-controlled heating plate is increased; when the indication of the thermocouple temperature measuring device is higher than the target temperature, liquid nitrogen is introduced again and the temperature of the temperature-controlled heating plate is lowered, so that the temperature of the copper plate can be regulated between -100°C and -0°C.

[0029] Preferably, when the additive manufacturing method is used in step S4:

[0030] The raw material in step S2 is loaded into an ink direct writing 3D printer as printing ink, and an in-situ freezing technology is used as an aid to design and print a dilute solution model pattern on a cooled copper plate;

[0031] The nozzle diameter of the ink direct writing 3D printer is 10-1000μm, the printing pressure is 5-100psi, the needle speed is 1-50mm / s, the layer height is consistent with the nozzle diameter, and the printed shape and structure are modeled by 3D software and sliced ​​and imported into the printer system for use;

[0032] The shapes of dilute solution models printed by the ink direct writing 3D printer in S4 can be customized, including grid, snake, honeycomb or interdigitated shapes.

[0033] Preferably, the dilute solution does not have shear-thinning properties, but high-resolution patterning can still be achieved using ink direct writing 3D printing.

[0034] Compared with the prior art, the present invention has the following beneficial technical effects:

[0035] 1. Thinner ink system and high-resolution pattern forming: Breaking the convention that the printing ink used in ink direct writing 3D printing should have shear thinning properties, high-resolution ink direct writing 3D printing pattern forming can still be achieved using thin ink that does not have shear thinning properties.

[0036] 2. Simplified process and low cost: The present invention provides a method for building a temperature-controlled freezing platform, which has a simple process and low cost and is suitable for mass production.

[0037] 3. Adjustable freezing platform temperature: By controlling the amount of liquid nitrogen introduced and the heating temperature of the temperature-controlled heating plate, the temperature of the copper plate can be controlled within a certain range.

[0038] 4. Optimized microstructure: Through directional freezing technology, the preparation of microscopic porous structures of dilute solutions can be achieved, providing new ideas for the formation of porous microstructures.

[0039] 5. Adjustable macroscopic geometric structure: The dilute solution model pattern prepared by the method of the present invention has an adjustable macroscopic structure, which can meet user needs through personalized design and be effectively applied in practice.

[0040] 6. Wide applicability: The dilute solution direct writing 3D printing method on a temperature-controlled freezing platform proposed in the present invention is also applicable to the preparation of micro-porous aerogels. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is the structural diagram of the temperature-controlled freezing platform;

[0042] Figure 2 Cross-section of the temperature-controlled freezing platform;

[0043] Figure 3 This is the temperature control flow chart of the temperature controlled freezing platform;

[0044] Figure 4 This is the rheological property test diagram of sodium alginate dilute ink;

[0045] Figure 5 This is a comparison chart of the molding effect of printing sodium alginate dilute ink without using a temperature-controlled freezing platform and with using a temperature-controlled freezing platform;

[0046] Figure 6 This is a cross-sectional SEM image of the printed sodium alginate dilute ink sample.

[0047] Figure numerals: 1. copper plate; 2. platform top cover; 3. platform bottom shell; 4. insulation layer; 5. liquid nitrogen tank; 6. temperature control heating plate; 7. digital display temperature control module; 8. thermocouple temperature measuring device. DETAILED DESCRIPTION

[0048] Example 1

[0049] This embodiment provides a temperature-controlled freezing platform, including a copper plate 1, a platform top cover 2, a platform bottom shell 3, an insulation layer 4, a liquid nitrogen bin 5, a temperature-controlled heating plate 6, a digital display temperature control module 7 and a thermocouple temperature measuring device 8, wherein:

[0050] The copper plate 1 is placed in the circular hole on the platform top cover 2, and the bottom surface of the copper plate 1 is engaged with the flange around the circular hole on the bottom surface of the platform top cover 2;

[0051] The platform top cover 2 is installed with the platform bottom shell 3 through L-shaped latches at the four corners;

[0052] The thermal insulation layer 4 is filled in the platform bottom shell 3 , and a groove is provided in the central area thereof for carrying the liquid nitrogen tank 5 .

[0053] The liquid nitrogen tank 5 is placed in the groove in the central area of ​​the thermal insulation layer 4 .

[0054] The adhesive backing of the temperature-controlled heating plate 6 is bonded to the lower surface of the copper plate 1 .

[0055] The digital display temperature control module 7 is connected to the temperature control heating plate 6 through electric wires.

[0056] The temperature measuring lead of the thermocouple temperature measuring device 8 is connected to the copper plate 1; the temperature of the temperature control platform is regulated between -100°C and 0°C.

[0057] The completed temperature-controlled freezing platform is as follows: Figure 1 As shown, the installation relationship of the internal structures of the temperature-controlled freezing platform is as follows Figure 2 Shown in cross-sectional view.

[0058] Example 2

[0059] This embodiment provides a temperature control method for a temperature-controlled refrigeration platform, and adjusts the temperature of the temperature-controlled refrigeration platform constructed in Example 1, including two types of adjustment: heating and cooling. The specific operations are as follows:

[0060] 1. Heating operation: When the temperature of the copper plate 1 on the temperature-controlled freezing platform is lower than the target temperature, the liquid nitrogen should be stopped from entering the temperature-controlled freezing platform, and the temperature of the copper plate 1 should be raised by controlling the temperature-controlled heating plate 6 through the digital display temperature control module 7.

[0061] 2. Cooling operation: When the temperature of the copper plate 1 on the temperature-controlled freezing platform is higher than the target temperature, liquid nitrogen should be introduced into the temperature-controlled freezing platform, and the temperature of the copper plate 1 should be lowered by controlling the temperature-controlled heating plate 6 through the digital display temperature control module 7.

[0062] The specific temperature adjustment process of the temperature-controlled freezing platform is as follows: Figure 3 shown.

[0063] Example 3

[0064] This embodiment provides a high-precision thin ink direct writing 3D printing method based on a temperature-controlled freezing platform, and the specific implementation steps are as follows:

[0065] 1. Prepare dilute solution ink: Mix sodium alginate and deionized water in a mass ratio of 50:1, stir for 1 hour using a stirring-degassing machine, and then degas for 30 minutes.

[0066] 2. Direct ink writing 3D printing without using a temperature-controlled freezing platform: The prepared dilute solution ink is loaded into an ink direct writing 3D printer, and the printer nozzle diameter is set to 15 μm, the printing pressure is 10 psi, and the needle speed is 20 mm / s. The dilute solution model pattern is designed and printed on a copper plate 1 at room temperature.

[0067] Example 4

[0068] This embodiment provides a high-precision thin ink direct writing 3D printing method based on a temperature-controlled freezing platform, using the temperature-controlled freezing platform in Example 1 and the temperature adjustment method in Example 2 for temperature adjustment, and the specific implementation steps are as follows:

[0069] 1. Build a temperature-controlled freezing platform: Assemble the copper plate 1, platform top cover 2, platform bottom shell 3, insulation layer 4, liquid nitrogen bin 5, temperature-controlled heating plate 6, digital display temperature control module 7 and thermocouple temperature measuring device 8 according to Example 1 to make a temperature-controlled freezing platform.

[0070] 2. Prepare dilute solution ink: Mix sodium alginate and deionized water in a mass ratio of 50:1, stir for 1 hour using a stirring-degassing machine, and then degas for 30 minutes.

[0071] 3. Adjust the temperature of the temperature-controlled freezing platform: After a certain amount of liquid nitrogen is introduced and the copper plate 1 reaches a certain low temperature state, turn on the temperature-controlled heating plate 6 to heat it to a certain temperature. When the reading of the thermocouple temperature measuring device 8 is lower than the target temperature, stop introducing liquid nitrogen and increase the temperature of the temperature-controlled heating plate 6; when the reading of the thermocouple temperature measuring device 8 is higher than the target temperature, introduce liquid nitrogen again and lower the temperature of the temperature-controlled heating plate 6, and adjust the temperature of the copper plate 1 on the temperature-controlled freezing platform to 0°C.

[0072] 4. Perform in-situ directional freezing-assisted ink direct writing 3D printing: Load the prepared dilute solution ink into an ink direct writing 3D printer, set the printer nozzle diameter to 15 μm, the printing pressure to 10 psi, and the needle speed to 20 mm / s, use in-situ freezing technology as an aid, design and print the dilute solution model pattern on the cooled copper plate 1.

[0073] 5. Freeze-dry the printed dilute solution model pattern for 12 hours at -50°C.

[0074] 6. Obtain lightweight materials with microscopic porous structures, which can be used for manufacturing lightweight structural devices and microscopic porous devices.

[0075] Example 5

[0076] This embodiment provides a high-precision thin ink direct writing 3D printing method based on a temperature-controlled freezing platform, using the temperature-controlled freezing platform in Example 1 and the temperature adjustment method in Example 2 for temperature adjustment, and the specific implementation steps are as follows:

[0077] 1. Build a temperature-controlled freezing platform: Assemble the copper plate 1, platform top cover 2, platform bottom shell 3, insulation layer 4, liquid nitrogen bin 5, temperature-controlled heating plate 6, digital display temperature control module 7 and thermocouple temperature measuring device 8 according to Example 1 to make a temperature-controlled freezing platform.

[0078] 2. Prepare dilute solution ink: Mix sodium alginate and deionized water in a mass ratio of 50:1, stir for 1 hour using a stirring-degassing machine, and then degas for 30 minutes.

[0079] 3. Adjust the temperature of the temperature-controlled freezing platform: After a certain amount of liquid nitrogen is introduced and the copper plate 1 reaches a certain low temperature state, turn on the temperature-controlled heating plate 6 to heat it to a certain temperature. When the reading of the thermocouple temperature measuring device 8 is lower than the target temperature, stop introducing liquid nitrogen and increase the temperature of the temperature-controlled heating plate 6; when the reading of the thermocouple temperature measuring device 8 is higher than the target temperature, introduce liquid nitrogen again and lower the temperature of the temperature-controlled heating plate 6, and adjust the temperature of the copper plate 1 on the temperature-controlled freezing platform to -20°C.

[0080] 4. Perform in-situ directional freezing-assisted ink direct writing 3D printing: Load the prepared dilute solution ink into an ink direct writing 3D printer, set the printer nozzle diameter to 15 μm, the printing pressure to 10 psi, and the needle speed to 20 mm / s, use in-situ freezing technology as an aid, design and print the dilute solution model pattern on the cooled copper plate 1.

[0081] 5. Freeze-dry the printed dilute solution model pattern for 12 hours at -50°C.

[0082] 6. Obtain lightweight materials with microscopic porous structures, which can be used for manufacturing lightweight structural devices and microscopic porous devices.

[0083] Example 6

[0084] This embodiment provides a high-precision thin ink direct writing 3D printing method based on a temperature-controlled freezing platform, using the temperature-controlled freezing platform in Example 1 and the temperature adjustment method in Example 2 for temperature adjustment, and the specific implementation steps are as follows:

[0085] 1. Build a temperature-controlled freezing platform: Assemble the copper plate 1, platform top cover 2, platform bottom shell 3, insulation layer 4, liquid nitrogen bin 5, temperature-controlled heating plate 6, digital display temperature control module 7 and thermocouple temperature measuring device 8 according to Example 1 to make a temperature-controlled freezing platform.

[0086] 2. Prepare dilute solution ink: Mix sodium alginate and deionized water in a mass ratio of 50:1, stir for 1 hour using a stirring-degassing machine, and then degas for 30 minutes.

[0087] 3. Adjust the temperature of the temperature-controlled freezing platform: After a certain amount of liquid nitrogen is introduced and the copper plate 1 reaches a certain low temperature state, turn on the temperature-controlled heating plate 6 to heat it to a certain temperature. When the reading of the thermocouple temperature measuring device 8 is lower than the target temperature, stop introducing liquid nitrogen and increase the temperature of the temperature-controlled heating plate 6; when the reading of the thermocouple temperature measuring device 8 is higher than the target temperature, introduce liquid nitrogen again and lower the temperature of the temperature-controlled heating plate 6, and adjust the temperature of the copper plate 1 on the temperature-controlled freezing platform to -40°C.

[0088] 4. Perform in-situ directional freezing-assisted ink direct writing 3D printing: Load the prepared dilute solution ink into an ink direct writing 3D printer, set the printer nozzle diameter to 15 μm, the printing pressure to 10 psi, and the needle speed to 20 mm / s, use in-situ freezing technology as an aid, design and print the dilute solution model pattern on the cooled copper plate 1.

[0089] 5. Freeze-dry the printed dilute solution model pattern for 12 hours at -50°C.

[0090] 6. Obtain lightweight materials with microscopic porous structures, which can be used for manufacturing lightweight structural devices and microscopic porous devices.

[0091] Example 7

[0092] This embodiment provides a high-precision thin ink direct writing 3D printing method based on a temperature-controlled freezing platform, using the temperature-controlled freezing platform in Example 1 and the temperature adjustment method in Example 2 for temperature adjustment, and the specific implementation steps are as follows:

[0093] 1. Build a temperature-controlled freezing platform: Assemble the copper plate 1, platform top cover 2, platform bottom shell 3, insulation layer 4, liquid nitrogen bin 5, temperature-controlled heating plate 6, digital display temperature control module 7 and thermocouple temperature measuring device 8 according to Example 1 to make a temperature-controlled freezing platform.

[0094] 2. Prepare dilute solution ink: Mix sodium alginate and deionized water in a mass ratio of 50:1, stir for 1 hour using a stirring-degassing machine, and then degas for 30 minutes.

[0095] 3. Adjust the temperature of the temperature-controlled freezing platform: After a certain amount of liquid nitrogen is introduced and the copper plate 1 reaches a certain low temperature state, turn on the temperature-controlled heating plate 6 to heat it to a certain temperature. When the reading of the thermocouple temperature measuring device 8 is lower than the target temperature, stop introducing liquid nitrogen and increase the temperature of the temperature-controlled heating plate 6; when the reading of the thermocouple temperature measuring device 8 is higher than the target temperature, introduce liquid nitrogen again and lower the temperature of the temperature-controlled heating plate 6, and adjust the temperature of the copper plate 1 on the temperature-controlled freezing platform to -60°C.

[0096] 4. Perform in-situ directional freezing-assisted ink direct writing 3D printing: Load the prepared dilute solution ink into an ink direct writing 3D printer, set the printer nozzle diameter to 15 μm, the printing pressure to 10 psi, and the needle speed to 20 mm / s, use in-situ freezing technology as an aid, design and print the dilute solution model pattern on the cooled copper plate 1.

[0097] 5. Freeze-dry the printed dilute solution model pattern for 12 hours at -50°C.

[0098] 6. Obtain lightweight materials with microscopic porous structures, which can be used for manufacturing lightweight structural devices and microscopic porous devices.

[0099] Table 1 Example parameters and dilute solution printing effect

[0100]

[0101]

[0102] The experimental data in Table 1 are analyzed to show that when the dilute solution model pattern is directly written by ink in different temperature environments of the copper plate 1, when the temperature of the copper plate 1 is not set to room temperature or the temperature of the copper plate 1 is set to 0°C without using the temperature-controlled freezing platform, the forming effect of the dilute solution model pattern directly written by ink is poor; when the temperature of the copper plate 1 is set to -20°C using the temperature-controlled freezing platform, the dilute solution model pattern can be basically formed by direct writing by ink, but the resolution is low; when the temperature of the copper plate 1 is set to above -40°C using the temperature-controlled freezing platform, the forming effect of the dilute solution model pattern directly written by ink is good. This indicates that the use of this method can promote the forming effect of the dilute solution model pattern directly written by ink.

[0103] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto, and various changes can be made within the knowledge scope of technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A temperature-controlled freezing platform device, characterized in that: It includes copper plate, platform top cover, platform bottom shell, insulation layer, liquid nitrogen tank, temperature control heating plate, digital display temperature control module and thermocouple temperature measuring device, among which: The copper plate is placed in the circular hole on the platform top cover, and the bottom surface of the copper plate is engaged with the flange around the circular hole on the bottom surface of the platform top cover; The platform top cover is installed with the platform bottom shell through L-shaped latches at the four corners; The insulation layer is filled in the platform bottom shell, and a groove is opened in its central area to carry the liquid nitrogen tank; The liquid nitrogen tank is placed in the groove in the central area of ​​the insulation layer; The adhesive backing of the temperature-controlled heating plate is bonded to the lower surface of the copper plate; The digital display temperature control module is connected to the temperature control heating plate through wires; The temperature measuring lead of the thermocouple temperature measuring device is connected to the copper plate; the temperature of the temperature control platform is regulated between -100°C and 0°C.

2. The temperature-controlled freezing platform device according to claim 1, characterized in that: The copper plate has a diameter of 60 mm and a thickness of 2 mm. It has good thermal conductivity and is used to carry the pattern model printed by the ink direct writing 3D printer.

3. The temperature-controlled freezing platform device according to claim 1, characterized in that: The temperature-controlled heating plate can achieve precise heating temperature control between 0-100°C through the digital display control module; the temperature-controlled freezing platform can complete the adjustment within a certain temperature range when liquid nitrogen is introduced.

4. The temperature-controlled freezing platform device according to claim 1, characterized in that: The liquid nitrogen tank is a stainless steel bowl with a truncated cone-shaped appearance. The diameter of the top opening is 60mm, the bottom diameter is 40mm, the height is 28mm, and the wall thickness is 1mm. It is used to carry the liquid nitrogen passed into the temperature-controlled freezing platform to achieve a continuous low-temperature environment in the temperature-controlled freezing platform.

5. The temperature-controlled freezing platform device according to claim 1, characterized in that: The thermal insulation layer is aluminum silicate thermal insulation cotton, and the thermal insulation layer is filled into the temperature-controlled freezing platform to achieve a continuous low-temperature freezing effect of the temperature-controlled freezing platform.

6. The temperature-controlled freezing platform device according to claim 1, characterized in that: The platform bottom shell is made of PLA material through 3D printing. The platform bottom shell is 120mm long, 75mm wide, 38mm high, and 1mm thick. The side opening is convenient for liquid nitrogen input. The platform top cover is made of PLA material through 3D printing. The platform top cover is 120mm long, 75mm wide and 2mm thick. There is a 60mm diameter round hole on the top and a 1mm thick flange around the round hole on the bottom to support the copper plate. L-shaped pins are designed at the four corners of the bottom surface of the platform top cover to achieve the installation of the platform top cover and the platform bottom shell.

7. A high-precision thin ink direct writing 3D printing method, using the temperature-controlled freezing platform described in any one of claims 1 to 6 for printing, characterized in that: The specific steps include: S1. Build a temperature-controlled freezing platform; assemble the copper plate, platform top cover, platform bottom shell, insulation layer, liquid nitrogen tank, temperature-controlled heating plate, digital display temperature control module and thermocouple temperature measuring device into a temperature-controlled freezing platform; S2. Prepare dilute solution raw materials; mix sodium alginate and deionized water in a certain mass ratio and stir; S3, introducing liquid nitrogen into the temperature-controlled freezing platform built in step S1, turning on the temperature-controlled heating plate, and adjusting the copper plate on the temperature-controlled freezing platform to a certain temperature; S4, the diluted solution prepared in step S2 is loaded into the needle tube of the ink direct writing 3D printer, and the pattern is printed on the copper plate on the temperature-controlled freezing platform set to the temperature in step S3; The dilute solution used is a solution without shear-thinning properties, and the printed product pattern is a high-resolution pattern.

8. The high-precision dilute ink direct writing 3D printing method based on a temperature-controlled freezing platform according to claim 7, characterized in that: When the dilute solution ink slurry in S2 is stirred, a magnetic stirrer is used to stir for 1 to 12 hours to fully mix, or it is manually ground for 20 minutes to 2 hours, or a stirring-degassing machine is used to stir for 10 minutes to 1 hour and then degas for 10 minutes to 1 hour.

9. The high-precision dilute ink direct writing 3D printing method based on a temperature-controlled freezing platform according to claim 7, characterized in that: The setting of the copper plate temperature in S3 includes the following steps: The adhesive backing of the temperature-controlled heating plate is attached to the bottom surface of the copper plate. When a certain amount of liquid nitrogen is introduced and the copper plate reaches a certain low temperature state, the temperature-controlled heating plate is turned on to heat it to a certain temperature. When the indication of the thermocouple temperature measuring device is lower than the target temperature, the liquid nitrogen is stopped from being introduced and the temperature of the temperature-controlled heating plate is increased; when the indication of the thermocouple temperature measuring device is higher than the target temperature, liquid nitrogen is introduced again and the temperature of the temperature-controlled heating plate is lowered, so that the temperature of the copper plate can be regulated between -100°C and -0°C.

10. The high-precision dilute ink direct writing 3D printing method based on a temperature-controlled freezing platform according to claim 7, characterized in that: The nozzle diameter of the ink direct writing 3D printer in S4 is 10-1000μm, the printing pressure is 5-100psi, the needle speed is 1-50mm / s, the layer height is consistent with the nozzle diameter, and the printed shape and structure are modeled by 3D software and sliced ​​and imported into the printer system for use.

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