A three-dimensional microstructure forming method based on aerosol jet printing

Abstract

The application provides a three-dimensional microstructure forming method based on aerosol jet printing, which is used for realizing controllable precision printing of three-dimensional microstructure. The application relates to the technical fields of intelligent manufacturing, additive manufacturing, printed electronics or inkjet printing. The forming method comprises the following steps: determining the solid content phi1 of aerosol ink; determining printing process parameters according to the type of the ink, and determining the solid content of aerosol flow, the deposition efficiency rho1 and the deposition rate rho2 of the aerosol ink according to the aerosol flow deposition rate measuring device and the solid content phi1 of the aerosol ink under the determined printing process parameters; determining the minimum amount of ink required for printing the three-dimensional microstructure and the printing time according to the deposition efficiency rho1 and the deposition rate rho2 of the aerosol ink; and manufacturing the three-dimensional microstructure by using the layer-by-layer manufacturing method according to the minimum amount of ink and the printing time. The application expands the application of aerosol jet printing in the field of three-dimensional microstructure forming.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent manufacturing, additive manufacturing, printed electronics or inkjet printing, and in particular to a three-dimensional microstructure forming method based on aerosol jet printing. BACKGROUND

[0002] As a new emerging inkjet printing technology, aerosol jet printing has the advantages of fast printing speed, high throughput and wide material compatibility, and is widely used in various fields such as human-computer interaction, life health and intelligent sensing. In particular, due to the convergence effect of the sheath gas, the working height of aerosol jet printing is relatively high. In addition, the solid content of the ink used for aerosol jet printing can reach 50% to 60%, which ensures good adhesion of the jet printing material to the substrate and three-dimensional forming capability, so aerosol jet printing technology not only can manufacture planar structures, but also is suitable for preparing three-dimensional microstructures on complex surfaces.

[0003] However, the preparation of three-dimensional microstructure on complex surface is affected by many factors, such as the solid content of ink, which is an important parameter of ink properties and directly determines the throughput of the manufacturing process, and is of great significance to engineering manufacturing. However, the functional materials in the ink used in inkjet printing are mostly micron and nanometer, and it is difficult to determine the volume. The mass fraction is often used instead of the volume fraction when the ink is configured. However, to precisely manufacture three-dimensional structures, the volume fraction of the functional materials in the ink needs to be determined. In the aerosol jet printing process, the ink is first atomized into aerosol, and then gathered from the nozzle by sheath gas. In this mass transfer process, the aerosol droplets will evaporate, resulting in a change in the solid content of the ink, that is, the solid content of the aerosol flow from the nozzle is inconsistent. The solid content of the aerosol flow is more directly related to manufacturing because the evaporation effect is significant, but the evaporation process is currently unobservable and cannot be quantitatively evaluated. For example, the evaporation rate itself is an important parameter of aerosol ink, which has important guiding significance for the design of aerosol ink composition. Aerosol droplets are often composed of liquid and solid functional materials. If the evaporation is too fast, the liquid phase may completely dry, and the micron and nanometer solid phase will lack inertia and cannot be deposited on the substrate; if the evaporation is too slow, the aerosol flow contains a large amount of liquid phase, and the solid content is too low, which cannot provide good adhesion and conformality. Therefore, the solvent of the aerosol ink usually adds low-boiling-point volatile and high-boiling-point difficult-to-volatile solvents, but this composition design process is very difficult because the evaporation rate cannot be quantitatively calculated. For example, the deposition rate of aerosol jet printing is affected by the type of ink and process parameters. Since the aerosol jet printing process of ink atomization and aerosol mass transfer is difficult to observe, and the evaporation effect of aerosol droplets will cause a significant change in the solid content of the droplets, there is currently no method to establish the relationship between the properties of the ink and the deposition rate, so it is very difficult to obtain a three-dimensional microstructure of a specific size by using aerosol jet printing. The uncertain printed structure not only affects the printing accuracy of the three-dimensional microstructure, but also may cause bridging, short circuiting and other failures of the circuit, which greatly limits the development and application of aerosol jet printing technology in the field of precise manufacturing of three-dimensional microstructure. SUMMARY

[0004] The present application is aimed at the bottleneck of the prior art and the development needs, and proposes a three-dimensional microstructure forming method based on aerosol jet printing, which is used to realize controllable and precise printing of three-dimensional microstructure.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] The present application proposes an aerosol flow deposition rate measuring device for measuring the deposition rate of aerosol flow; the device comprises a substrate, a nozzle and a high-speed camera;

[0007] The substrate is provided with n micro ink wells;

[0008] The nozzle is used to atomize the ink into an aerosol flow and spray it into the micro ink well;

[0009] The high-speed camera is used to capture the time when the aerosol flow enters the ink well and fills the ink well.

[0010] Further, the volume of the above-mentioned ink well is V3=πdr 2 ; Wherein, d is the depth of the ink well, r is the radius of the ink well.

[0011] The present application based on the above-mentioned aerosol flow deposition rate measuring device also proposes a three-dimensional microstructure forming method based on aerosol printing, which is used to realize the controllable precision printing of three-dimensional microstructure. The method comprises the following steps:

[0012] Step S1: determining the solid content of the aerosol ink

[0013] Step S2: determining the printing process parameters according to the type of ink, and determining the solid content of the aerosol flow, the deposition efficiency ρ1 and the deposition rate ρ2 of the aerosol ink according to the aerosol flow deposition rate measuring device and the solid content of the aerosol ink under the determined printing process parameters;

[0014] Step S3: determining the minimum amount of ink required for printing three-dimensional microstructure and printing time according to the deposition efficiency ρ1 and the deposition rate ρ2 of the aerosol ink;

[0015] Step S4: manufacturing three-dimensional microstructure by using the layer-by-layer manufacturing method according to the minimum amount of ink and printing time.

[0016] Further, the above-mentioned step S1 is specifically:

[0017] Step S11: selecting V1 volume of ink, and drying for 2h at 40℃ under vacuum to obtain completely dried functional material;

[0018] Step S12: measuring the volume V2 of the completely dried functional material;

[0019] Step S13: calculating the solid content of the aerosol ink

[0020] Further, the above-mentioned printing process parameters include atomization parameters, nozzle diameter and gas flow;

[0021] The atomization parameters include ink viscosity, ink temperature, atomization power;

[0022] ​The ink viscosity is 0-50 cp; the ink temperature is 5-35℃; and the atomization power is 15-50V.

[0023] Further, the above step S2 is specifically:

[0024] Step S21: Under the determined printing process parameters, turn on the atomizer and gas flow switch and keep for more than 10s to obtain a stable aerosol flow;

[0025] Step S22: Move the nozzle to the center of the ink well quickly, and capture the time of the aerosol flow entering the ink well and filling the ink well by a high-speed camera;

[0026] Step S23: Scan the n ink wells in turn, and calculate the average time t of filling the ink well;

[0027] Step S24: Prepare a single line, scan to obtain the three-dimensional structure volume V4 of the single line, and calculate the solid content of the aerosol flow

[0028] Step S25: According to the solid content of the aerosol flow Calculate the evaporation rate of the aerosol in the mass transfer process

[0029] Step S26: Post-treat the prepared single line, and take the post-treated single line as the smallest unit of three-dimensional microstructure manufacturing, and scan to obtain the cross-sectional width a, height h and volume V5 of the single line;

[0030] Step S27: Calculate the shrinkage ratio of the printed structure

[0031] Step S28: According to the shrinkage ratio, calculate the deposition efficiency of the aerosol ink under the printing process parameters And the deposition rate ρ2 = V5 / t.

[0032] Further, there are two ways to regulate the morphology of the three-dimensional microstructure unit, which are:

[0033] Method one, increasing the printing speed can reduce the cross-sectional width a and height h by the same proportion;

[0034] Method two, increasing the sheath gas flow can increase the aspect ratio h / a.

[0035] Further, the above step S4 is specifically:

[0036] Step S41: Slice the target three-dimensional microstructure in the height direction with height h as the basic unit to obtain a two-dimensional graph with a thickness of h;

[0037] Step S42: print each layer of the obtained two-dimensional pattern from outside to inside in turns, and the step length is a;

[0038] Step S43: print the three-dimensional microstructure from bottom to top layer by layer according to the determined process parameters, after each layer of pattern is printed, post-processing is performed, and then the next layer is printed, until the three-dimensional microstructure is obtained.

[0039] The three-dimensional microstructure forming method based on aerosol jet printing can be embedded in a computer readable storage medium or a computer device to realize intelligent printing.

[0040] The application further provides a computer device, which comprises a memory and a processor, and the memory stores a computer program.

[0041] The application has the following beneficial effects:

[0042] 1. The application provides a three-dimensional microstructure forming method based on aerosol jet printing, which calculates important evaluation indexes in three-dimensional microstructure manufacturing, i.e., deposition efficiency, deposition rate and evaporation rate of aerosol ink, to provide an important basis for realizing three-dimensional microstructure.

[0043] Further, the application designs an aerosol flow deposition rate measuring device for characterizing the evaporation rate of aerosol, thereby establishing a relationship model between water properties and deposition rate, deducing the expression of evaporation rate and deposition rate, and realizing precise additive manufacturing of three-dimensional microstructure with a minimum cross-sectional unit of 10 mu m x 2 mu m (width x height).

[0044] Further, the existing ink configuration often uses mass fraction instead of volume fraction. However, to perform precise manufacturing of three-dimensional structure, it is necessary to determine the volume fraction of functional materials of ink.

[0045] The application is suitable for aerosol jet printing in the field of three-dimensional microstructure forming. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0047] Figure 1 is a structural diagram of the aerosol flow deposition rate measuring device described in the present application;

[0048] Figure 2 is a schematic diagram of a printing path planning of the three-dimensional microstructure slice pattern described in the present application.

[0049] In the above description, 1 represents a substrate with a micro ink well, 2 represents a micro ink well, 3 represents an aerosol flow, 4 represents a high-speed camera, 5 represents a nozzle, and 6 represents ink in the ink well. Specific embodiments

[0050] In the following description, specific details are set forth in order to provide a thorough understanding of embodiments of the application. However, persons of ordinary skill in the art will readily recognize that embodiments of the application can be practiced without these specific details. In other instances, well-known structures, devices, circuits, and methods have not been described in detail in order to avoid obscuring the application.

[0051] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be pointed out that those skilled in the art can make several changes and improvements without departing from the concept of the present application, and these changes and improvements are within the scope of protection of the present application.

[0052] Embodiment one, see Figure 1 This embodiment describes an aerosol flow deposition rate measuring device, which realizes the deposition rate determination of the aerosol flow, and thus realizes the controllable precision printing of the three-dimensional microstructure.

[0053] As shown in Figure 1 The measuring device comprises a substrate 1, a nozzle 5 and a high-speed camera 4.

[0054] The substrate 1 is provided with n micro ink wells 2.

[0055] The nozzle 5 is used to atomize the ink 6 into an aerosol flow 3 and spray it into the micro ink well 2.

[0056] The high-speed camera 4 is used to capture the time of the aerosol flow 3 entering the ink well and filling the ink well.

[0057] In actual application, the depth of the ink well is d and the radius is r, so the volume of the ink well V3 = πdr 2 At the same time, in order to ensure that the aerosol flow can be filled into the ink well and take into account the accuracy of measurement, the nozzle size <2r = d <2.5 × nozzle size.

[0058] Embodiment two, based on the aerosol flow deposition rate measuring device described in the above embodiment one, proposes a three-dimensional microstructure forming method based on aerosol jet printing, which is used to realize the controllable precision printing of three-dimensional microstructure.

[0059] The three-dimensional microstructure forming method comprises the following steps:

[0060] Step S1: determining the solid content of the aerosol ink

[0061] Step S2: determining the printing process parameters according to the type of ink, and under the determined printing process parameters, determining the solid content of the aerosol flow, the deposition efficiency ρ1 and the deposition rate ρ2 of the aerosol ink according to the aerosol flow deposition rate measuring device and the solid content of the aerosol ink;

[0062] Step S3: determining the minimum amount of ink required for printing three-dimensional microstructure and printing time according to the deposition efficiency ρ1 and the deposition rate ρ2 of the aerosol ink;

[0063] Step S4: using the layer-by-layer manufacturing method to manufacture three-dimensional microstructure according to the minimum amount of ink and printing time.

[0064] Embodiment three, this embodiment is a specific description of step S1 in the three-dimensional microstructure forming method based on aerosol jet printing proposed in the above embodiment two;

[0065] Step S1: determining the solid content of the aerosol ink

[0066] Specifically includes:

[0067] Step S11: selecting V1 volume of ink, and drying in vacuum at 40℃ for 2h to obtain completely dried functional material;

[0068] Step S12: measuring the volume V2 of the completely dried functional material;

[0069] Step S13: calculating the solid content of the aerosol ink

[0070] ​In practical application, the printing ink is selected according to actual needs. The aerosol ink is usually composed of functional materials, solvents and additives. The functional materials are usually micron or nanometer in size, and it is difficult to determine the volume fraction thereof. The mass fraction instead of the volume fraction is usually used in the existing ink configuration. However, in order to precisely manufacture a three-dimensional structure, the volume fraction of the functional materials in the ink needs to be determined. Therefore, it is very important to determine the volume fraction of the functional materials in the ink. Therefore, the three-dimensional microstructure forming method described in the embodiment is calculated around the volume fraction. The solid content of the aerosol ink is also determined around the volume fraction. The specific determination method is as follows: a certain amount of ink is taken in a plastic tube (the volume is denoted as V1), and the plastic tube is dried at 40°C under vacuum for 2h to obtain completely dried functional materials and other difficult-to-volatilize substances. The plastic tube is scanned by a high-resolution micro-CT to obtain the volume of the dried substances, which is denoted as V2. The solid content of the ink can be calculated as follows:

[0071] Further, the functional materials in the ink can be nanosilver, nanocopper, nanogold and other metal materials for electrical conduction; can be polyimide, methacrylate, photocurable resin and other polymer materials for insulation; can be graphene, MXene, PDOT:PSS and other sensing materials for pressure, temperature and humidity sensing; can be ZnO, ZnS and other quantum dot materials for light emission; can be Bi2Te3, PbTe and other thermoelectric materials for energy conversion, perovskite, GaP and other photovoltaic materials, and MnSe, MnS, VSe2 and other energy storage materials.

[0072] Embodiment four, the embodiment is a specific description of step S2 in the three-dimensional microstructure forming method based on aerosol jet printing provided in the above-mentioned embodiment two;

[0073] Step S2: determining the printing process parameters according to the type of ink, and measuring the deposition rate of the aerosol flow and the solid content of the aerosol ink under the determined printing process parameters The solid content of the aerosol flow and the deposition efficiency ρ1 and deposition rate ρ2 of the aerosol ink are determined;

[0074] Specifically, it includes:

[0075] Step S21: under the determined printing process parameters, the atomizer and the gas flow switch are turned on and kept for more than 10s to obtain a stable aerosol flow;

[0076] Step S22: the nozzle is quickly moved to the center of the ink well, and the time when the aerosol flow enters the ink well and fills the ink well is captured by a high-speed camera;

[0077] Step S23: the n ink wells are scanned in sequence, and the average time t of filling the ink well is calculated;

[0078] Step S24: a single line is prepared, and a three-dimensional structure volume V4 of the single line is scanned to calculate the solid content of the aerosol flow

[0079] Step S25: according to the solid content of the aerosol flow The evaporation rate of the aerosol in the mass transfer process is calculated

[0080] Step S26: the prepared single line is post-processed, and the post-processed single line is taken as the smallest unit of three-dimensional microstructure manufacturing, and the cross-sectional width a, height h and volume V5 of the single line are scanned

[0081] Step S27: the shrinkage ratio of the printed structure is calculated

[0082] Step S28: according to the shrinkage ratio, the deposition efficiency of the aerosol ink under the printing process parameters is calculated and the deposition rate ρ2 = V5 / t.

[0083] In actual application, the embodiment specifically includes the following steps:

[0084] 1. Determination of printing process parameters: appropriate atomization parameters can be selected according to the actual ink type, including ink temperature and atomization power. For higher viscosity ink, higher ink temperature and larger atomization power should be selected to ensure the generation of stable aerosol flow. The ink viscosity is 0-50 cp, the ink temperature is 5-35℃, and the atomization power is 15-50V. Appropriate nozzle diameter and gas flow can also be selected according to the required minimum cross-sectional unit size of the target three-dimensional microstructure, specifically: nozzle size < 20 x minimum feature size in target structure, carrier gas flow fixed (4-50 sccm), sheath gas flow / carrier gas flow > 2.

[0085] 2. Measurement of deposition rate of aerosol flow: the aerosol flow deposition rate measuring device proposed in the above embodiment one is used at this time, and the measuring device is placed in a closed environment with the saturated vapor pressure of the solvent component of the aerosol ink to avoid evaporation of the aerosol flow after leaving the nozzle. Under the above determined process parameters, the printing is carried out, the atomizer and gas flow switch are turned on and kept for more than 10 s to obtain a stable aerosol flow, then the nozzle is quickly moved to the center of the ink well, and the time for the aerosol flow to enter the ink well and fill the ink well is recorded as t1 by a high-speed camera. In order to maximize the calculation accuracy and reduce the error, n ink wells are scanned in turn, and the average time for filling the ink well is calculated

[0086] 3. Solid content of aerosol flow: according to actual needs, select a printing substrate (such as silicon, glass, metal, PET, PI, etc.), print for t1 length at a constant printing speed (1-20 mm / s), obtain a single line structure, dry it at 40℃ for 2h to obtain a completely dried printed pattern. Use a laser confocal microscope to scan the three-dimensional structure of the line, and obtain its volume V4. The solid content of the aerosol flow can be calculated At the same time, the evaporation rate of the aerosol in the mass transfer process can be calculated as In the three-dimensional microstructure configuration, this evaporation rate can be maintained to prevent too fast evaporation, which can completely dry the liquid phase, resulting in a micronanometer-sized solid phase that lacks inertia due to its mass and cannot be deposited onto the substrate; and too slow evaporation, which can cause the aerosol flow to contain a large amount of liquid phase components, resulting in a low solid content and a fluid that cannot provide good adhesion and conformality when printed onto the substrate.

[0087] 4. Shrinkage ratio of printed microstructure unit: according to actual needs, select a post-processing method to post-process the printed pattern in step 3 above, and obtain a single line after post-processing, which is the smallest unit of three-dimensional microstructure manufacturing. Again use a laser confocal microscope to scan the three-dimensional structure of the line, and obtain its cross-sectional width a, height h, and volume V5. In particular, increasing the printing speed in step 3 above can reduce the cross-sectional width a and height h by the same ratio; increasing the sheath gas flow in step 1 above can increase the aspect ratio h / a. By these two methods, the morphology of the microstructure unit can be controlled. The shrinkage ratio of the printed structure can be calculated The deposition efficiency of the selected aerosol ink under the printing parameters is The deposition rate p2 = V5 / t.

[0088] The deposition efficiency and deposition rate calculated in this embodiment are important evaluation indicators in three-dimensional microstructure manufacturing, for the following reasons: the deposition efficiency is used to evaluate the performance of the ink, that is, how much volume of the ink can actually contribute to three-dimensional microstructure manufacturing. The larger this value, the better the ink, which is an important evaluation indicator in three-dimensional microstructure manufacturing. The deposition rate evaluates the manufacturing performance and directly indicates the process throughput. According to this value, the printing time can be directly obtained by combining the volume of the microstructure to be manufactured. Therefore, the deposition efficiency and deposition rate are important evaluation indicators in three-dimensional microstructure manufacturing and are the basis for manufacturing three-dimensional microstructures.

[0089] Embodiment five, see Figure 2 This embodiment is described to specifically illustrate step S4 in the three-dimensional microstructure forming method based on aerosol jet printing proposed in embodiment two above;

[0090] S41: slice the target three-dimensional microstructure in the height direction with height h as a basic unit to obtain a two-dimensional pattern with a thickness of h;

[0091] S42: print each layer of the obtained two-dimensional pattern from outside to inside in a circle, with a step length of a;

[0092] S43: print the three-dimensional microstructure layer by layer from bottom to top according to the determined process parameters, perform post-processing after each layer of pattern is printed, and then print the next layer until the three-dimensional microstructure is obtained.

[0093] In actual application, the volume of the three-dimensional microstructure to be manufactured is V6, and the minimum amount of ink V7 = V6 / ρ1 can be calculated according to the deposition efficiency; in order to ensure the continuous generation of stable aerosol flow, the volume of the added ink V8 > 10V7. At the same time, the printing time t = V6 / ρ1 can also be calculated. The specific manufacturing steps are as follows: using the layer-by-layer manufacturing method to perform additive manufacturing of the 3D microstructure, slicing the target structure in the height direction with height h as a basic unit, i.e. dividing the three-dimensional structure with height H into H / h two-dimensional patterns with thickness h, for each layer of the obtained two-dimensional pattern, printing path planning is performed in the manner shown, printing from outside to inside in a circle, with a step length of a; and printing the three-dimensional microstructure layer by layer from bottom to top under the above determined printing process parameters, performing post-processing after each layer of pattern is printed, and then printing the next layer. In-situ curing devices can also be used to perform real-time post-processing on the printed pattern to improve the printing efficiency. Figure 2

[0094] Further, the post-processing is specifically as follows: for metal nanoparticle ink, constant temperature heating or pulse light sintering is used to connect the nanoparticles to improve conductivity; when using constant temperature heating, the heating temperature is 150-800℃, and the heating time is 10-120min; when using pulse light sintering, the pulse amplitude is 400-800V, and the pulse width is 1000-10000μs; for light-cured materials, ultraviolet light is used for post-processing, the ultraviolet light wavelength is 365-405nm, and the curing time is 5-20min.

[0095] Embodiment six, see Figure 1 and Figure 2 This embodiment is an actual manufacturing description of the three-dimensional microstructure forming method based on aerosol jet printing proposed in the above embodiment;

[0096] Silver nanoparticle ink is used to manufacture micro-conductive cubes.

[0097] Specifically,

[0098] 1. Determination of solid content of aerosol ink:

[0099] ​The most widely used silver nanoparticle conductive ink was selected, with a viscosity of 20 cp, a functional material of silver nanoparticles, an average particle size of 50 nm, a solvent of water and ethylene glycol, and an additive of acrylic resin.

[0100] The ink V1 = 0.2 ml was taken in a plastic tube and vacuum dried at 40°C for 2 h to obtain completely dried functional materials and other non-volatile substances. The plastic tube was scanned using high-resolution micro-CT to obtain the volume V2 = 0.016 of the dried substances. The solid content of the ink can be calculated

[0101] 2. Determination of printing process parameters:

[0102] The ink tank was placed in a constant temperature water bath at 18°C, and the atomization power was 35V. The target three-dimensional microstructure was a conductive cube with a length x width x height of 200μm x 200μm x 25μm, with a precision of ±5μm. Therefore, a nozzle size of 100μm was selected, the carrier gas flow was 6sccm, and the sheath gas flow was 20sccm.

[0103] 3. Determination of the deposition rate of the aerosol flow:

[0104] The deposition rate of the aerosol flow was measured using the measuring device shown in Figure 1 , wherein the depth d of the ink well was 200μm and the radius r was 100μm, so the volume V3 of the ink well was πdr 2 = 0.0063mm 3 . The above device was placed in a closed environment saturated with water and ethylene glycol vapor pressure to avoid evaporation of the aerosol flow after leaving the nozzle. Under the process parameters described in step 2, the atomizer and gas flow switch were turned on and kept for 15s to obtain a stable aerosol flow, then the nozzle was quickly moved to the center of the ink well, and the time for the aerosol flow to enter the ink well and fill the ink well was captured by a high-speed camera. The average time to fill the ink well was calculated by sequentially scanning 36 ink wells

[0105] 4. Determination of the solid content of the aerosol flow:

[0106] A single line structure was obtained by printing on a glass substrate at a constant printing speed of 10mm / s for 8.7s, and then drying the printed pattern at 40°C for 2h to obtain completely dried functional materials. The three-dimensional structure of the line was scanned using a laser confocal microscope, and the volume V4 of the line was 0.0021mm 3 . The solid content of the aerosol flow can be calculated The evaporation rate of the aerosol during the mass transfer process can be represented as

[0107] 5. Determination of the shrinkage ratio of the printed structure:

[0108] The single line on the glass substrate in step 4 is heated at 200℃ for 10 min, and the cross-sectional width a = 14.2 μm, height h = 6.2 μm, and volume V5 = 0.0014 mm 3 The shrinkage ratio of the printed structure can be calculated The selected aerosol ink deposition efficiency under the printing parameters The deposition rate ρ2 = V5 / t1 = 1.61 × 10 -4 mm 3 / s. The printing speed and sheath gas flow are adjusted, and when the sheath gas flow is 24 sccm and the printing speed is 17.6 mm / s, the minimum unit size a = 10.0 μm and the height h = 5.0 μm of the three-dimensional microstructure are obtained.

[0109] 6. Printing a three-dimensional microstructure:

[0110] To ensure the continuous generation of stable aerosol flow, 2 ml of ink is added to the ink tank. The additive manufacturing of the 3D microstructure is performed by using a layer-by-layer manufacturing method. The target structure is sliced in the height direction with a height of 5 μm as a basic unit, that is, a three-dimensional structure with a height of 25 μm is divided into five two-dimensional patterns with a thickness of 5 μm. The two-dimensional pattern obtained in each layer is an equal 200 μm × 200 μm rectangle, and the printing path planning is performed in the manner shown in the figure, and the printing is performed from the outside to the inside in a circle, and the step length is 10 μm. Figure 2

[0111] Under the conditions of an ink water bath at 18℃, an atomization power of 35V, a carrier gas flow of 6 sccm, a sheath gas flow of 24 sccm, and a printing speed of 17.6 mm / s, the three-dimensional microstructure is printed layer by layer from bottom to top, and after each layer of pattern is printed, it is heated at 200℃ for 10 min, and then the next layer is printed. The actual size of the three-dimensional micro conductive cube obtained is length × width × height = 204.1 μm × 199.8 μm × 25.3 μm, and the volume error is only 3.1%.

[0112] In summary, the calculation method of the aerosol jet printing deposition rate is developed, the experimental device for testing the aerosol flow solid content is designed, the aerosol evaporation rate is characterized, the relationship model between the ink properties and the deposition rate is established, the expressions of the evaporation rate and the deposition rate are derived, and the three-dimensional microstructure precision additive manufacturing with a minimum cross-sectional unit of 10 μm × 2 μm (width × height) is realized. The application of aerosol jet printing in the field of three-dimensional microstructure forming is expanded.

[0113] ​Embodiment eight, the three-dimensional microstructure forming method based on aerosol jet printing provided in the above embodiments can be embedded in a computer readable storage medium or a computer device to realize intelligent printing. Therefore, the present embodiment provides a computer readable storage medium, and a computer program is stored on the computer readable storage medium. When the computer program is run by a processor, the processor executes the three-dimensional microstructure forming method based on aerosol jet printing described above.

[0114] The present embodiment also provides a computer device, which comprises a memory and a processor. The memory stores a computer program. When the processor runs the computer program stored in the memory, the processor executes the three-dimensional microstructure forming method based on aerosol jet printing described above.

[0115] The computer device provided in the present embodiment includes a general-purpose hardware device, which is not represented in the form of a diagram. The system includes a processor and a memory. The processor and the memory can be connected through a bus or other means. The memory is a non-transitory computer readable storage medium, which can be used to store a non-transitory software program, a non-transitory computer executable program and modules, and corresponding program instructions / modules. The processor executes various functions and data processing of the processor by running the non-transitory software program, instructions and modules stored in the memory, so as to realize the above method.

[0116] The above only describes the embodiments of the present application and does not limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

Claims

1. A three-dimensional microstructure forming method based on aerosol printing, characterized in that: The forming method is implemented based on an aerosol flow deposition rate measuring device, which includes a substrate, a nozzle, and a high-speed camera; There are n micro ink wells on the substrate; The nozzle is used to atomize the ink into an aerosol stream and spray it into the micro ink well; A high-speed camera is used to capture the time it takes for the aerosol stream to enter and fill the ink well; The method is: S1: Determine the solid content φ1 of aerosol ink; S2: Determine the printing process parameters according to the type of ink, and under the printing process parameters, measure the solid content of the aerosol flow and the deposition efficiency of the aerosol ink according to the aerosol flow deposition rate measurement device and the solid content φ1 of the aerosol ink. ρ 1 and deposition rate ρ 2; S2 is specifically: S21: Turn on the nebulizer and gas flow switch and keep them on for more than 10 s to obtain a stable aerosol flow; S22: The nozzle is quickly moved to the center of the ink well, and the time it takes for the aerosol flow to enter the ink well and fill the ink well is captured by a high-speed camera; S23: Scan sequentially n ink wells, calculate the average time to fill the ink wells t ; S24: Prepare a single line and scan it to obtain the three-dimensional structure volume of the single line V 4. Calculate the solid content of the aerosol flow φ2= V 4 / V 3; S25: Calculate the evaporation rate of aerosol during mass transfer φ3=(φ2-φ1) / φ2; S26: Post-process the prepared single line, and use the single line after post-processing as the minimum unit for three-dimensional microstructure manufacturing, and scan to obtain the cross-sectional width of the single line a ,high h and volume V 5; S27: Calculate the shrinkage ratio of the printed structure φ4= V 5 / V 4; S28: Calculate the deposition efficiency of the aerosol ink under the printing process parameters according to the shrinkage ratio ρ 1=φ1φ4= V 5 V 2 / V 1 V 4 and deposition rate ρ 2= V 5 / t ; S3: According to the deposition efficiency of aerosol ink ρ 1 and deposition rate ρ 2. Determine the minimum amount of ink and printing time required to print three-dimensional microstructures; S4: Three-dimensional microstructures are manufactured using a layer-by-layer approach based on the minimum ink usage and printing time.

2. The method for forming a three-dimensional microstructure based on aerosol printing according to claim 1, characterized in that: The volume of the ink well is V 3=π dr 2 ;in, d is the depth of the ink well, r is the radius of the ink well.

3. The method for forming a three-dimensional microstructure based on aerosol printing according to claim 1, characterized in that: S1 is specifically: S11: Select V 1 volume of ink and dried under vacuum at 40 °C for 2 h to obtain completely dry functional materials; S12: Measuring the volume of completely dried functional materials V 2; S13: Calculate the solid content of aerosol ink φ1= V 2 / V 1.

4. The method for forming a three-dimensional microstructure based on aerosol printing according to claim 1, characterized in that: Printing process parameters include atomization parameters, nozzle diameter, and gas flow rate; Atomization parameters include ink viscosity, ink temperature, and atomization power; The ink viscosity is 0-50 cp; the ink temperature is 5-35℃; the atomization power is 15-50V.

5. The method for forming a three-dimensional microstructure based on aerosol printing according to claim 1, characterized in that: There are two ways to control the morphology of three-dimensional microstructure units: one, Increasing the printing speed can reduce the cross-sectional width a、 high h ; 2. Increasing the sheath gas flow rate can increase the aspect ratio h / a。 6. The method for forming a three-dimensional microstructure based on aerosol printing according to claim 1, characterized in that: S4 is specifically: S41: The target three-dimensional microstructure is h Slice the basic unit in the height direction and obtain a thickness of h Two-dimensional graphics; S42: Printing the two-dimensional pattern obtained in each layer in a circle from outside to inside, with a step length of a; S43: Printing the three-dimensional microstructure layer by layer from bottom to top according to the determined process parameters, performing post-processing after each layer of graphics is printed, and then printing the next layer until the three-dimensional microstructure is obtained.

7. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed by a processor, executes the three-dimensional microstructure forming method based on aerosol printing according to claim 1.

8. A computer device, characterized in that: The device includes a memory and a processor, wherein a computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes the three-dimensional microstructure forming method based on aerosol printing according to claim 1.

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