Dual-mode 3D printing nozzle, method and device for manufacturing curved film

Abstract

The invention relates to a dual-mode 3D printing nozzle, method and device for manufacturing a curved film, the dual-mode 3D printing nozzle comprises a charging barrel, the bottom end of the charging barrel is connected with a printing head, and the top end of the charging barrel is connected with an air pump through an air supply pipe, the dual-mode 3D printing nozzle is characterized in that a pressure regulating valve is arranged on the air supply pipe, the printing head is connected with the positive electrode of a power supply, and a fixed sleeve is arranged on the periphery of the printing head; the top end of the fixed sleeve is fixed to the bottom end of the charging barrel, the bottom of the fixed sleeve is provided with a cooling bin coaxially arranged on the periphery of the printing head in a sleeving mode, the cooling bin is connected into a cooling circulation pipeline, and a heating element is arranged between the cooling bin and the bottom end of the fixed sleeve.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and particularly to a dual-mode 3D printing nozzle, device and method for manufacturing curved thin films. Background Art

[0002] The statements herein only provide background art related to the present invention and do not necessarily constitute prior art.

[0003] The curved multi-layer circuit manufacturing technology is an advanced technology for manufacturing multi-layer circuits on complex curved substrates, which can be decomposed into the manufacturing of curved thin films and curved circuits. In recent years, it has received extensive attention in the fields of flexible electronics, wearable devices, aerospace, and biomedicine.

[0004] Among them, the main manufacturing methods of curved thin films include solution film-forming technology, electrospray deposition technology, transfer printing technology, and 3D printing technology. Among them, the solution film-forming technology has become a widely used preparation method in the industry due to its simple process, low equipment investment cost, and good film thickness uniformity. However, this technology is difficult to apply to complex surfaces with large curvatures, and microcracks are easily generated in the thin film due to stress concentration during the solvent evaporation process; the electrospray deposition technology has the advantages of high material utilization rate and low cost, and is suitable for thin film deposition on complex curved substrates. However, this technology has problems such as large surface roughness of the deposited thin film and low deposition efficiency; the transfer printing technology has the advantages of high yield and high manufacturing accuracy. However, due to the physical characteristics of the transfer printing process, it cannot be applied to non-developable surfaces with non-zero Gaussian curvature, and during the multi-layer thin film transfer process, the interlayer interconnected vias are prone to misalignment, seriously affecting the electrical performance of the product. Compared with traditional technologies, 3D printing technology has been widely used in curved surface printing, and has the advantages of low cost, simple structure, and strong ability to form complex three-dimensional structures. Among them, the extrusion 3D printing technology is applicable to materials with a viscosity range of 100-100000 mPa·s, and can manufacture thin films with a film thickness of 50-500 μm. However, this technology has a staircase effect in manufacturing curved thin films. When used for curved surfaces with large curvatures, the film thickness non-uniformity is greater than 10%, and the surface roughness is high; the inkjet printing technology has the advantages of high efficiency and high-precision forming of curved surfaces, but the applicable material viscosity range is 10-300 mPa·s, and the film thickness non-uniformity on large-curvature surfaces is greater than 15%; the electrospray printing technology also has a wide range of applicable materials, and can manufacture feature structures with a resolution lower than 1 μm and curved thin films with a film thickness of 1-5 μm, but it cannot meet the requirements of thick film manufacturing. At the same time, the curved thin film materials in curved multi-layer circuits are mostly low-viscosity dielectric materials, which will flow along the curved surface during the printing process, affecting the uniformity of thick film manufacturing. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a dual-mode 3D printing nozzle, device and method for the production of curved thin films, which can realize dual-mode printing and can not only print curved thin films of 1-5μm, but also print thicker films, and ensure the uniformity of the thick film.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In the first aspect, an embodiment of the present invention provides a dual-mode 3D printing nozzle for the production of curved thin films, including a barrel, the bottom end of the barrel is connected to a print head, the top end of the barrel is connected to an air pump through an air supply pipe, the air supply pipe is provided with a pressure regulating valve, the print head is connected to the positive pole of a power supply, a fixed sleeve is provided on the outer periphery of the print head, the top end of the fixed sleeve is fixed to the bottom end of the barrel, a cooling bin is provided at the bottom of the fixed sleeve which is coaxially sleeved on the outer periphery of the print head, the cooling bin is connected to a cooling circulation pipeline, and a heating element is provided between the cooling bin and the bottom end of the fixed sleeve.

[0008] Optionally, the heating element is a ceramic heating ring.

[0009] Optionally, the bottom end of the print head and the bottom surface of the heating element are staggered in the vertical direction, and the bottom end surface of the print head is located 1 mm-3 mm below the bottom surface of the heating element.

[0010] Optionally, the print head is made of metal, and the inner diameter of the print head is 220-250 μm.

[0011] Optionally, the length of the cooling chamber along the axial direction is smaller than the length of the print head, and the cooling chamber is made of a thermally conductive insulating material.

[0012] Optionally, the top end of the barrel is also connected to a feed pump via a feed pipe.

[0013] In a second aspect, an embodiment of the present invention provides a working method of a dual-mode 3D printing nozzle for curved film production: including an electrospray printing mode and a material extrusion 3D printing mode;

[0014] When the electrospray printing mode is working, the print head is adjusted to a preset first printing height, gas is injected into the barrel through an air pump, the barrel air pressure is adjusted to a first air pressure through a pressure regulating valve, a power supply applies a gradually increasing voltage to the print head until the voltage reaches the first voltage, the printing material is driven into the print head through the first set air pressure, the printing material is ejected from the print head and forms a Taylor cone at the tip of the print head under the action of the electric field, and as the voltage increases, the liquid material breaks through the surface tension to form a jet, and the printing material is deposited on the printing substrate;

[0015] When the material extrusion 3D printing mode works, the print head is adjusted to a preset second printing height. Air is injected into the barrel of the air pump box, and the air pressure in the barrel is adjusted to the second air pressure through a pressure regulating valve. The power supply applies a second voltage to the print head. Under the action of the second air pressure, the printing material is extruded from the print head, and the power supply injects positive charges into the printing material through the nozzle. The positive charges accumulate in the printing material and, under the action of an external electric field, cause the printing material to spread evenly on the printing substrate.

[0016] Optionally, the first voltage is 600V - 1000V, and the second voltage is 1500 - 2200V.

[0017] Optionally, the first printing height is 2 / 3 - 2 times the inner diameter of the print head, and the second printing height is 10μm - 20μm.

[0018] In a second aspect, an embodiment of the present invention provides a dual - mode 3D printing device for making curved - surface films, including the dual - mode 3D printing nozzle for making curved - surface films described in the first aspect. The barrel is connected to a three - axis linkage mechanism. A workbench is provided below the print head, and an arc - shaped substrate structure is provided on the upper surface of the workbench. The workbench is connected to a rotating member, and the rotating member can drive the workbench to rotate around its own axis. The rotating member is connected to a rotation driving mechanism, and the rotation driving mechanism can drive the rotating member and the workbench to rotate in a vertical plane.

[0019] The beneficial effects of the present invention are as follows:

[0020] 1. For the print head and working method of the present invention, through the pressure regulating valve, different air pressures can be applied to the barrel, thereby realizing the switching between the electro - spray mode for discharging materials and the extrusion mode for discharging materials. Through the power supply, different voltages can be applied to the print head, thereby realizing the switching between the electro - spray printing mode and the material extrusion 3D printing mode. Through the electro - spray printing mode, thin - film printing with a smaller thickness can be performed, and through the material extrusion 3D printing mode, thick - film printing can be carried out. Moreover, when printing, positive charges can be injected into the printing material through the voltage applied by the power supply. The positive charges are difficult to dissipate and accumulate in the material, which will enhance the electro - wetting effect under the action of an external electric field, enabling the material to spread evenly on the curved surface of the substrate, solving the problem of uneven printing of curved - surface films in material extrusion 3D printing. The same set of print heads can achieve two printing modes, meeting the printing requirements for a wide range of film thicknesses and improving the applicability of the entire print head.

[0021] 2. For the print head and working method of the present invention, a heating element and a cooling chamber are provided. When using a low - viscosity material, the heating element can heat the printing material ejected from the print head to a semi - cured state, achieving a balance between fluidity and shape accuracy, reducing the influence of material fluidity on curved - surface printing. At the same time, the cooling chamber can prevent the material in the nozzle from being heated and cured, thus preventing nozzle blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0023] Figure 1 is a schematic diagram of the overall structure of Embodiment 1 of the present invention;

[0024] Figure 2 is a schematic diagram of the cooperation of the print head, fixed sleeve, ceramic heating ring and cooling chamber in Embodiment 1 of the present invention;

[0025] Figure 3 is a schematic diagram of the working process of the electrospray printing mode in Embodiment 2 of the present invention;

[0026] Figure 4 is a schematic diagram of the deposition of printing material on the substrate surface in current material extrusion 3D printing;

[0027] Figure 5 is a schematic diagram of the deposition of printing material on the substrate surface in the material extrusion 3D printing mode of Embodiment 2 of the present invention;

[0028] Among them, 1. Workbench, 2. Printing substrate, 301. Fixed sleeve, 302. Cooling chamber, 303. Ceramic heating ring, 4. Pulse power supply, 5. Injection pump, 6. Three-axis linkage mechanism, 7. Pressure regulating valve, 8. Fixed frame, 9. Barrel, 10. Print head, 11. Microscope. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Embodiment 1

[0030] This embodiment provides a dual-mode 3D printing nozzle for making curved thin films, as Figure 1 - Figure 2As shown, the barrel 9 includes a material barrel 9, which is used to hold printing materials. In this embodiment, the printing material is a polyimide solution or a polydimethylsiloxane solution, etc. A printing material with heat curing ability and a viscosity range of 0-10000mPa·s can be selected, and those skilled in the art can select it according to actual needs. The top end of the barrel 9 is connected to one end of the air supply pipe, and the other end of the air supply pipe is connected to the air pump. The air pump can pass gas into the barrel 9, thereby promoting the discharge of the printing material in the barrel. The air supply pipe is provided with a pressure regulating valve 7 for adjusting the gas pressure in the barrel 9. The top of the barrel 9 is also connected to a feed pipe, which is connected to a material pump. The material pump is used to add printing material to the barrel to meet the needs of large-area printing. In this embodiment, the material pump can be an existing syringe pump 5. A print head 10 is coaxially arranged at the bottom of the barrel 9. The print head is made of metal, preferably, stainless steel. The inner diameter of the print head is 220μm-250μm, and the outer diameter is 400μm-450μm. The technical personnel in this field can set the size according to actual needs. The print head is made of metal and has good thermal conductivity.

[0031] A fixed sleeve 303 is provided on the periphery of the print head 10, and the fixed sleeve 303 is coaxially arranged with the print head 10. The top end of the fixed sleeve 303 is sleeved on the periphery of the bottom end of the barrel 9 and is fixed by friction. A cooling bin 302 is provided at the bottom end of the fixed sleeve 303, and the cooling bin 302 is coaxially arranged with the print head 10. The cooling bin 302 is arranged on the periphery of the print head 10. A heating element is provided between the cooling bin 302 and the bottom end of the fixed sleeve 303. In this embodiment, the heating element adopts a ceramic heating ring 301, and the ceramic heating ring 301 is connected to a power source through a wire and can be heated after power is turned on. In this embodiment, the cooling bin 302, the ceramic heating ring 301 and the fixed sleeve 303 are coaxially arranged, and the bottom surfaces of the cooling bin 302, the ceramic heating ring 301 and the fixed sleeve 303 are flush. The bottom end of the print head 10 is staggered with the bottom surface of the ceramic heating ring 301 in the vertical direction, and the bottom end surface of the print head is located 1mm-3mm below the bottom surface of the ceramic heating ring, preferably 2mm. In this embodiment, part of the print head 10 is exposed, which will not cause significant interference to the required electric field strength, thereby ensuring the effect of electrospray printing.

[0032] The ceramic heating ring 301 can be made using existing equipment. Its outer shape can be obtained by cutting the ceramic, and a heating function can be imparted by 3D printing a circuit on its surface. The ceramic heating ring 301 is coaxially arranged with the fixed sleeve 303 and the print head 10 to ensure the uniformity of the heating of the printing material below the print head. According to the requirements of the heating condition, the size of the ceramic heating ring 301 should be appropriate, capable of heating the printing material directly below to a semi-cured state without overheating other positions, and having a large enough inner diameter to install the cooling chamber 302. Specifically, the outer diameter of the ceramic heating ring 301 should not be too large to prevent overheating of other positions; and the inner diameter of the ceramic heating ring 301 cannot be too small to ensure that the cooling chamber 302 has a large enough outer diameter to sufficiently cool the print head 10; at the same time, the inner diameter of the ceramic heating ring 301 cannot be too small, otherwise it will affect the heating efficiency of the ceramic heating ring 301. In summary, the inner diameter of the ceramic heating ring 301 is selected to be 7 mm and the outer diameter is 14 mm.

[0033] According to the geometric dimensions of the ceramic heating ring 301, the outer diameter of the cooling chamber 302 can be selected to be 7 mm, and the inner diameter should fit the print head 10. If the error is large, silicone grease can be applied to the print head 10 to reduce the gap between the two, so that the print head 10 fits the inner ring surface of the cooling chamber 302, preventing the thermosetting printing material in the print head 10 from being blocked by the influence of the ceramic heating ring 301.

[0034] Along the axial direction of the fixed sleeve 303 and the print head 10, the axial dimension of the cooling chamber 302 is smaller than the axial dimension of the print head 10. The cooling chamber 302 is made of a material with good thermal conductivity and insulation properties. Preferably, the cooling chamber 302 is made of silicone rubber material. The cooling chamber 302 is connected to a cooling circulation pipeline. Therefore, the cooling chamber 302 is provided with a coolant inlet and a coolant outlet. The coolant inlet is connected to a coolant source through a coolant inlet pipe, and the coolant outlet is connected to a coolant discharge pipe. By introducing coolant, the print head is cooled to prevent the printing material from solidifying in the print head and blocking the print head.

[0035] In this embodiment, the coolant source includes a liquid pump. The liquid pump is connected to the coolant inlet pipe, and the liquid pump is connected to a liquid storage tank through a pipeline. The liquid storage tank is used to hold the coolant, and the liquid pump can send the coolant in the liquid storage tank into the cooling chamber through the coolant inlet pipe. The coolant discharge pipe is connected to a collection tank, and the collection tank is used to collect the used coolant.

[0036] Preferably, the coolant inlet is arranged at the bottom of the cooling chamber, and the coolant outlet is arranged at the top of the cooling chamber so that the coolant can circulate fully.

[0037] Determine the geometric dimensions of the fixed sleeve according to the geometric dimensions of the ceramic heating ring and the cooling chamber, as well as the outer diameter of the selected barrel. The fixed sleeve is made of polytetrafluoroethylene or polyimide. Preferably, the fixed sleeve is made of a transparent material, so that the internal structure can be clearly observed during use, and timely adjustment can be made.

[0038] The print head 10 is connected to the positive pole of the power supply, and the negative pole of the power supply is grounded. In this embodiment, the power supply uses a pulsed power supply 4, which can output a pulsed voltage of 600V - 2200V.

[0039] The print head 10 is connected to the positive pole of the pulsed power supply 4 through a wire, and the connection method can adopt the existing technology and will not be described in detail here.

[0040] In this embodiment, the fixed sleeve 303 is provided with openings for the wires of the power supply, the wires of the ceramic heating ring 301, the coolant inlet pipe, and the coolant discharge pipe to pass through.

[0041] Embodiment 2

[0042] This embodiment provides a working method for a dual-mode 3D printing nozzle for curved film production described in Embodiment 1, including two working modes, namely the electrospray printing mode and the material extrusion 3D printing mode.

[0043] Among them, the electrospray printing mode is used to produce a film with a thickness not greater than 5μm. When the electrospray printing mode works, the existing electrospray printing technology can be adopted. The print head 10 is adjusted to a preset first printing height, gas is injected into the barrel 9 through an air pump, and the pressure of the barrel 9 is adjusted to a first pressure through a pressure regulating valve 7. In this embodiment, the first pressure is 300kPa - 500kPa, and those skilled in the art can set it according to actual needs. A back pressure is formed on the printing material through the first pressure. The printing material is affected by the back pressure, gravity, and viscous force. The power supply applies a first voltage to the print head 10, and the printing material is driven into the print head 10 through the first pressure. As Figure 3 shown, the printing material is ejected from the print head 10 and forms a Taylor cone at the tip of the print head 10 under the action of an electric field. As the voltage increases, the liquid material breaks through the surface tension under the combined action of the normal electric field force and the tangential electric field force to form a jet, and the printing material is deposited on the substrate.

[0044] Among them, the first voltage is 600V - 1000V, and those skilled in the art can set it according to actual needs. The printing height, that is, the distance between the bottom end of the print head and the substrate, is 2 / 3 - 2 times the inner diameter of the print head 10, and those skilled in the art can set it according to actual needs.

[0045] The material extrusion 3D printing mode is used to fabricate a film with a thickness greater than 5 μm. When the material extrusion 3D printing mode is working, the print head is adjusted to a preset second printing height. Air is injected into the barrel 9 of the air pump box, and the air pressure in the barrel is adjusted to a second air pressure through the pressure regulating valve 7. In this embodiment, the second air pressure is 400 kPa - 600 kPa, and those skilled in the art can set it according to actual needs. The power supply applies a second voltage to the print head. Under the action of the second air pressure, the printing material is extruded from the print head 10.

[0046] As Figure 4 shown, in traditional extrusion printing, no voltage is applied to the print head 10, which is not conducive to the spreading of the printing material on the substrate.

[0047] In this embodiment, the print head 10 is connected to the power supply. As Figure 5 shown, the power supply injects positive charges into the printing material via the nozzle. The positive charges accumulate in the printing material. Since the surface of the substrate is negatively charged, under the action of the applied electric field, the printing material spreads evenly on the substrate.

[0048] Among them, the second voltage is 1500 V - 2200 V, and those skilled in the art can set it according to actual needs. The printing height, that is, the distance between the bottom end of the print head 10 and the substrate, is 10 μm - 20 μm, and those skilled in the art can set it according to actual needs.

[0049] The positive charges injected into the printing material via the power supply - print head are difficult to dissipate and accumulate in the printing material, which will enhance the electro - wetting effect under the action of the applied electric field, enabling the printing material to spread evenly on the curved surface, solving the problem of uneven printing of curved - surface films in extrusion 3D printing.

[0050] When the printing material is a low - viscosity and thermosetting printing material, the ceramic heating ring 301 works at a set temperature. The set temperature is 40 °C - 80 °C, and those skilled in the art can set it according to actual needs. The cooling chamber works. The ceramic heating ring 301 can be used to turn the thermosetting material printed on the curved surface into a semi - cured state, achieving a balance between fluidity and shape - retention ability, reducing the influence of material fluidity on curved - surface printing, and preventing the material in the nozzle from being heated and cured to block the nozzle through the cooling chamber.

[0051] Using the 3D printing nozzle and working method of this embodiment, both electro - spray printing and extrusion 3D printing can be realized. Therefore, it is possible to fabricate films with a thickness not greater than 5 μm and films with a thickness greater than 5 μm. It has strong applicability, solves the problem of uneven printing of curved - surface films in material extrusion 3D printing. The same set of printing nozzles can achieve two printing modes, meeting the printing requirements for a wide range of film thicknesses and improving the applicability of the entire printing nozzle.

[0052] Embodiment 3

[0053] This embodiment provides a dual-mode 3D printing device for making curved thin films, as Figure 1 shown, including the dual-mode 3D printing nozzle for making curved thin films described in Embodiment 1.

[0054] The material cylinder 9 is connected to the three-axis linkage mechanism 6 through the fixing frame 8. The three-axis linkage mechanism 6 can drive the movement of the material cylinder 9. The three-axis linkage mechanism 6 can use existing equipment, and its specific structure will not be described in detail here. It can drive the material cylinder 9 and the print head 10 to move in two mutually perpendicular directions and the vertical direction in the horizontal plane.

[0055] A workbench 1 is provided below the print head 10. A print substrate 2 is provided on the workbench 1. The print substrate 2 adopts an arc structure. The shape of the print substrate 2 can be selected from shapes such as semi-cylindrical, hemispherical, conical, and irregular curved surfaces, but limited to shapes with a vertical rotation range greater than 180°. The print substrate 2 should be made of a hard material, such as quartz glass, ceramic, nylon, etc. In this embodiment, the print substrate 2 is a semi-circular ring-shaped glass substrate.

[0056] The workbench 1 can rotate 360° around its own axis and can also swing -90° - 90° in the vertical plane.

[0057] Specifically, the workbench 1 is connected to the rotary component. The rotary component can use an existing rotary platform. The moving part of the rotary platform is connected to the workbench and can drive the workbench to rotate around its own axis. Both sides of the rotary platform are connected to the rotation driving mechanism. The rotation driving mechanism uses a motor with a horizontally arranged axis. The output shaft of the motor is connected to the rotary platform and can drive the rotary platform and the workbench to swing -90° - 90° in the vertical plane.

[0058] The printing device further includes a microscope 11. The microscope 11 is located on one side of the print head 10 and is aligned with the print head 10. The microscope 11 is connected to the fixing frame 8 through the microscope bracket. The fixing frame 8 is connected to the three-axis linkage mechanism. The microscope 11 can move synchronously with the print head 10, and the staff can observe the printing situation of the print head 10 through the microscope 11.

[0059] The working method of the printing device in this embodiment is as follows:

[0060] First, select the printing mode according to the film thickness, determine the printing height, and determine the voltage to be applied to the print head 10.

[0061] Place the printing material inside the injection pump 5, connect the feeding tube and the air tube to the top of the cartridge 9, connect the print head 10 to the bottom end of the cartridge 9, fix the cartridge 9 on the moving part of the three-axis linkage mechanism 6 through the fixing bracket 8, and connect the print head 10 to the positive pole of the power supply 4 through a wire.

[0062] Fix the top end of the fixed sleeve 303 equipped with the ceramic heating ring 301 and the cooling chamber 302 to the bottom end of the cartridge 9, ensuring that the print head 10 passes through the cooling chamber 302.

[0063] Printing program setting: Fix the arc-shaped printing substrate 2 on the workbench 1 with hot melt adhesive, use the three-axis linkage mechanism 6 to move the print head 10 to the preset printing starting point, according to the post-film rotation printing mode, and preset the voltage, air pressure and the heating temperature of the ceramic heating ring 301 according to the program. Open the pre-designed printing program, start the coolant circulation, preheat with the ceramic heating ring 301, the air pump works, and then start printing.

[0064] When using the electrospray printing mode, the printing material is ejected from the print head 10 and forms a Taylor cone at the tip of the print head under the action of an electric field. As the voltage increases, the liquid material breaks through the surface tension to form a jet, and the printing material is deposited on the printing substrate 2.

[0065] When using the extrusion 3D printing mode, under the action of air pressure, the printing material is extruded from the print head, the power supply injects positive charges into the printing material through the nozzle, the positive charges accumulate in the printing material, and under the action of an external electric field, the printing material spreads evenly on the printing substrate 2.

[0066] After printing is completed, use the three-axis linkage mechanism to move the print head to the original position and remove the printed workpiece from the printing substrate 2.

[0067] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A dual-mode 3D printing nozzle for making curved surface films, comprising a barrel, the bottom end of the barrel is connected with a print head, and the top end of the barrel is connected with an air pump through an air supply pipe, characterized in that, A pressure regulating valve is provided on the air supply pipe. The print head is connected to the positive pole of the power supply. A fixed sleeve is provided on the outer periphery of the print head. The top end of the fixed sleeve is fixed to the bottom end of the material cylinder. A cooling chamber coaxially sleeved on the outer periphery of the print head is provided at the bottom of the fixed sleeve. The cooling chamber is connected to a cooling circulation pipeline. A heating element is provided between the bottom end of the cooling chamber and the bottom end of the fixed sleeve.

2. The dual-mode 3D printing nozzle for curved film production according to claim 1, characterized in that, The heating element uses a ceramic heating ring.

3. The dual-mode 3D printing nozzle for making curved thin films according to claim 1, wherein The bottom end of the print head and the bottom surface of the heating element are arranged offset in the vertical direction, and the bottom end surface of the print head is 1 mm - 3 mm below the bottom surface of the heating element.

4. The dual-mode 3D printing nozzle for curved film production according to claim 1, characterized in that, The print head is made of a metal material, and the inner diameter of the print head is 220 - 250 μm.

5. The dual-mode 3D printing nozzle for curved film production according to claim 1, characterized in that, The length of the cooling chamber in the axial direction is less than the length of the print head, and the cooling chamber is made of a thermally conductive and insulating material.

6. The dual-mode 3D printing nozzle for making curved surface films according to claim 1, wherein, The top end of the material cylinder is also connected to a material pump through a feed pipe.

7. A working method of the dual-mode 3D printing nozzle for curved surface thin film production according to any one of claims 1-6, characterized in that: It includes an electrospray printing mode and a material extrusion 3D printing mode; When the electrospray printing mode works, the print head is adjusted to a preset first printing height. Gas is injected into the material cylinder through an air pump. The air pressure in the material cylinder is adjusted to a first air pressure through the pressure regulating valve. The power supply applies a first voltage to the print head. The printing material is driven into the print head by the first set air pressure. The printing material is ejected from the print head and forms a Taylor cone at the tip of the print head under the action of an electric field. As the voltage increases, the liquid material breaks through the surface tension to form a jet, and the printing material is deposited on the printing substrate. When the material extrusion 3D printing mode works, the print head is adjusted to a preset second printing height. Gas is injected into the material cylinder through an air pump box. The air pressure in the material cylinder is adjusted to a second air pressure through the pressure regulating valve. The power supply applies a second voltage to the print head. Under the action of the second air pressure, the printing material is extruded from the print head. The power supply injects positive charges into the printing material through the nozzle. The positive charges accumulate in the printing material, and under the action of an external electric field, the printing material is evenly spread on the printing substrate.

8. The working method of the dual-mode 3D printing nozzle for making curved surface thin films according to claim 7, characterized in that, The first voltage is 600V - 1000V, and the second voltage is 1500 - 2200V.

9. The working method of the dual-mode 3D printing nozzle for curved surface thin film production according to claim 7, characterized in that, The first printing height is 2 / 3 - 2 times the inner diameter of the print head, and the second printing height is 10 μm - 20 μm.

10. A dual-mode 3D printing device for making curved thin films, characterized in that, It includes the dual-mode 3D printing nozzle for curved surface film production according to any one of claims 1 - 6. The material cylinder is connected to a three-axis linkage mechanism. A workbench is provided below the print head. An arc-shaped substrate structure is provided on the upper surface of the workbench. The workbench is connected to a rotating component. The rotating component can drive the workbench to rotate around its own axis. The rotating component is connected to a rotation driving mechanism, and the rotation driving mechanism can drive the rotating component and the workbench to rotate in a vertical plane.

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