Three-dimensional microstructure forming method based on aerosol jet printing

Abstract

The invention provides a three-dimensional microstructure forming method based on aerosol jet printing. The three-dimensional microstructure forming method is used for achieving controllable precision printing of a three-dimensional microstructure. Relates to the technical field of intelligent manufacturing, additive manufacturing, printing electronics or ink-jet printing. The forming method comprises the following steps: measuring the solid content phi 1 of the aerosol ink; printing process parameters are determined according to the types of the ink, and under the determined printing process parameters, the solid content of aerosol flow and the deposition efficiency rho1 and deposition rate rho2 of the aerosol ink are measured according to the aerosol flow deposition rate measuring device and the solid content phi1 of the aerosol ink; according to the deposition efficiency rho 1 and the deposition rate rho 2 of the aerosol ink, the minimum use amount of ink needed for printing the three-dimensional microstructure and the printing time are determined; and manufacturing the three-dimensional microstructure by adopting a layer-by-layer manufacturing method according to the minimum use amount of the ink and the printing time. According to the invention, the application of aerosol jet printing in the field of three-dimensional microstructure forming is expanded.

Description

Technical Field

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

[0002] As an emerging inkjet printing technology, aerosol printing technology 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 of sheath gas, the working height of aerosol printing is relatively high. In addition, the solid content of the ink used for aerosol printing can reach 50% to 60%, which ensures the good adhesion and three-dimensional forming ability of the printing material to the substrate. Therefore, aerosol printing technology can not only manufacture planar structures, but is also suitable for preparing three-dimensional microstructures on complex surfaces.

[0003] However, the preparation of three-dimensional microstructures on complex surfaces is affected by many factors, such as the solid content of the ink. The solid content itself is an important parameter of the ink properties, which 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 micrometer-level and nanometer-level, and it is difficult to determine their volume. When configuring the ink, mass fraction rather than volume fraction is often used. However, to carry out precision manufacturing of three-dimensional structures, it is necessary to clarify the volume fraction of the functional materials of the ink. In addition, in the aerosol printing process, the ink is first atomized into an aerosol, and then sprayed from the nozzle through the convergence of sheath gas. In this mass transfer process, the aerosol droplets will evaporate, resulting in changes in the solid content of the ink, that is, the solid content of the ink and the solid content of the aerosol flow sprayed from the nozzle are inconsistent. The solid content of the aerosol flow should be 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 must maintain an appropriate evaporation rate during the mass transfer process. Aerosol droplets are often composed of liquid and solid functional materials. If the evaporation is too fast, the liquid phase may be completely dry, and the micron-nano solid phase will not be able to be deposited on the substrate due to its light weight and lack of inertia; if the evaporation is too slow, the aerosol flow contains a large amount of liquid phase components, and the solid content is too low. It will become a fluid when printed on the substrate and cannot provide good adhesion and conformality. Therefore, the solvent of aerosol ink usually adds low-boiling point volatile solvents and high-boiling point non-volatile solvents, but this component design process is very difficult because the evaporation rate cannot be quantitatively calculated. For example, the deposition rate of aerosol printing is jointly affected by the type of ink and process parameters. Since the microscopic processes of ink atomization and aerosol mass transfer in aerosol printing are difficult to observe, and the evaporation effect of aerosol droplets will cause significant changes in the solid content of the droplets, there is currently no method to establish the relationship between ink properties and deposition rate. Therefore, it is very difficult to obtain three-dimensional microstructures of specific sizes using aerosol printing. Uncertain printing structures will not only affect the printing accuracy of three-dimensional microstructures, but may even cause circuit bridging, short circuits and other failures, greatly limiting the development and application of aerosol printing technology in the field of precision manufacturing of three-dimensional microstructures. Summary of the invention

[0004] In view of the bottlenecks and development needs of the prior art, the present invention proposes a three-dimensional microstructure forming method based on aerosol printing, which is used to achieve controllable precision printing of three-dimensional microstructures.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides an aerosol flow deposition rate measuring device, which is used to measure the deposition rate of the aerosol flow; the device includes a substrate, a nozzle and a high-speed camera;

[0007] n micro ink wells are provided on the substrate;

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

[0009] A high-speed camera is used to capture the time it takes for the aerosol stream to enter and fill the ink well.

[0010] Furthermore, the volume of the ink well is V3 = πdr 2 ; Wherein, d is the depth of the ink well and r is the radius of the ink well.

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

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

[0013] Step S2: Determine the printing process parameters according to the type of ink, and under the determined printing process parameters, measure the aerosol flow deposition rate according to the aerosol flow deposition rate measurement device and the solid content of the aerosol ink. The solid content of the aerosol flow, the deposition efficiency ρ1 and the deposition rate ρ2 of the aerosol ink were determined;

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

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

[0016] Furthermore, the above step S1 is specifically as follows:

[0017] Step S11: select ink with a volume of V1 and vacuum dry it at 40° C. for 2 h to obtain a completely dry 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] Furthermore, the above printing process parameters include atomization parameters, nozzle diameter and gas flow rate;

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

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

[0023] Furthermore, the above step S2 is specifically as follows:

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

[0025] Step S22: quickly move the nozzle to the center of the ink well, and capture the time when the aerosol flow enters the ink well and fills the ink well by a high-speed camera;

[0026] Step S23: Scan n ink wells in sequence and calculate the average time t for filling the ink wells;

[0027] Step S24: Prepare a single line and scan it 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 aerosol during mass transfer

[0029] Step S26: post-processing the prepared single line, and using the single line after post-processing as the minimum unit for manufacturing a three-dimensional microstructure, and scanning 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: Calculate the deposition efficiency of the aerosol ink under the printing process parameters according to the shrinkage ratio And the deposition rate ρ2 = V5 / t.

[0032] Furthermore, there are two ways to control the morphology of the three-dimensional microstructure unit, specifically:

[0033] Method 1: Increasing the printing speed can reduce the cross-sectional width a and height h in the same proportion;

[0034] Method 2: Increasing the sheath gas flow rate can increase the aspect ratio h / a.

[0035] Furthermore, the above step S4 is specifically as follows:

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

[0037] Step S42: Print the two-dimensional graphics obtained in each layer in a circle from outside to inside, with a step length of a;

[0038] Step 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.

[0039] The three-dimensional microstructure forming method based on aerosol printing proposed in the present invention can be embedded in a computer-readable storage medium or a computer device to realize intelligent printing. Therefore, the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the three-dimensional microstructure forming method based on aerosol printing is executed.

[0040] The present invention also provides a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes the above-mentioned three-dimensional microstructure forming method based on aerosol printing.

[0041] The beneficial effects of the present invention are:

[0042] 1. The present invention proposes a three-dimensional microstructure forming method based on aerosol printing, which provides an important basis for realizing three-dimensional microstructure by calculating the important evaluation indicators in the three-dimensional microstructure manufacturing: the deposition efficiency, deposition rate and evaporation rate of the aerosol ink.

[0043] Furthermore, the present invention designs an aerosol flow deposition rate measurement device for characterizing the aerosol evaporation rate, thereby establishing a relationship model between water properties and deposition rate, deriving expressions for evaporation rate and deposition rate, and realizing precision additive manufacturing of three-dimensional microstructures with a minimum cross-sectional unit of 10μm×2μm (width×height). This expands the application of aerosol printing in the field of three-dimensional microstructure molding.

[0044] Furthermore, conventional ink configuration often uses mass fractions rather than volume fractions. However, to perform precision manufacturing of three-dimensional structures, it is necessary to clarify the volume fractions of the functional materials in the ink. Therefore, the three-dimensional microstructure forming methods proposed in the present invention are all calculated based on volume fractions.

[0045] The invention is applicable to the field of aerosol printing in three-dimensional microstructure forming. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

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

[0049] Among them, 1 represents a substrate with micro ink wells, 2 represents the micro ink wells, 3 represents an aerosol flow, 4 represents a high-speed camera, 5 represents a nozzle, and 6 represents the ink in the ink wells. DETAILED DESCRIPTION

[0050] In the following description, specific details such as specific system structures and technologies are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0051] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

[0052] Implementation method 1, see Figure 1 The present embodiment is described. The present embodiment provides an aerosol flow deposition rate measuring device. The deposition rate of the aerosol flow can be measured by the measuring device, thereby achieving controllable precision printing of three-dimensional microstructures.

[0053] like Figure 1 As shown, the measuring device includes a substrate 1, a nozzle 5 and a high-speed camera 4;

[0054] n micro ink wells 2 are provided on the substrate 1;

[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 when the aerosol flow 3 enters the ink well and fills the ink well.

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

[0058] Embodiment 2: This embodiment proposes a three-dimensional microstructure forming method based on aerosol printing based on the aerosol flow deposition rate measurement device described in the above embodiment 1, which is used to achieve controllable precision printing of three-dimensional microstructures.

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

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

[0061] Step S2: Determine the printing process parameters according to the type of ink, and under the determined printing process parameters, measure the aerosol flow deposition rate according to the aerosol flow deposition rate measurement device and the solid content of the aerosol ink. The solid content of the aerosol flow, the deposition efficiency ρ1 and the deposition rate ρ2 of the aerosol ink were determined;

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

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

[0064] Embodiment 3: This embodiment specifically describes step S1 of the three-dimensional microstructure forming method based on aerosol printing proposed in the above embodiment 2;

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

[0066] Specifically include:

[0067] Step S11: select ink with a volume of V1 and vacuum dry it at 40° C. for 2 h to obtain a completely dry 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] When this embodiment is actually applied, 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 often in the micrometer and nanometer scale, and it is difficult to determine their volume. The existing configuration of ink often uses mass fraction rather than volume fraction. However, to carry out precision manufacturing of three-dimensional structures, it is necessary to clarify the volume fraction of the functional materials of the ink. Therefore, it becomes very important to determine the volume fraction of the functional materials of the ink. Therefore, the three-dimensional microstructure molding method described in this embodiment is calculated around the volume fraction, and the solid content of the aerosol ink measured first is also based on the volume fraction. The specific measurement method is: take an appropriate amount of ink in a plastic tube (the volume is denoted as V1), vacuum dry it at 40°C for 2h, and obtain completely dry functional materials and other non-volatile substances. Use a high-resolution micro CT to scan the plastic tube, and the volume of the dry substance is recorded as V2. The solid content of the ink can be calculated

[0071] Furthermore, the functional materials in the ink can be metal materials such as nanosilver, nanocopper, nanogold for conduction; they can also be polymer materials such as polyimide, methacrylate, photocurable resin for insulation; they can also be sensing materials such as graphene, MXene, PDOT:PSS for pressure, temperature, and humidity sensing; they can also be quantum dot materials such as ZnO and ZnS for luminescence; they can also be thermoelectric materials such as Bi2Te3 and PbTe for energy conversion, optoelectronic materials such as perovskite and GaP, and energy storage materials such as MnSe, MnS, and VSe2.

[0072] Embodiment 4: This embodiment specifically describes step S2 in the three-dimensional microstructure forming method based on aerosol printing proposed in the above embodiment 2;

[0073] Step S2: Determine the printing process parameters according to the type of ink, and under the determined printing process parameters, measure the aerosol flow deposition rate according to the aerosol flow deposition rate measurement device and the solid content of the aerosol ink. The solid content of the aerosol flow, the deposition efficiency ρ1 and the deposition rate ρ2 of the aerosol ink were determined;

[0074] Specifically include:

[0075] Step S21: Under the determined printing process parameters, turn on the atomizer and the gas flow switch and keep them for more than 10 seconds to obtain a stable aerosol flow;

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

[0077] Step S23: Scan n ink wells in sequence and calculate the average time t for filling the ink wells;

[0078] Step S24: Prepare a single line and scan it to obtain the three-dimensional structure volume V4 of the single line, and calculate the solid content of the aerosol flow

[0079] Step S25: According to the solid content of the aerosol flow Calculate the evaporation rate of aerosol during mass transfer

[0080] Step S26: post-processing the prepared single line, and using the single line after post-processing as the minimum unit for manufacturing a three-dimensional microstructure, and scanning to obtain the cross-sectional width a, height h and volume V5 of the single line;

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

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

[0083] In practical application, this implementation method specifically includes the following steps:

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

[0085] 2. Determination of the deposition rate of the aerosol flow: At this time, the aerosol flow deposition rate measuring device proposed in the first embodiment above is required, and the measuring device is placed in a closed environment with a saturated vapor pressure of the solvent component of the aerosol ink to prevent the evaporation of the aerosol flow after leaving the nozzle. Printing is performed under the above-determined process parameters, the atomizer and the gas flow switch are turned on and maintained for more than 10 seconds to obtain a stable aerosol flow, and then the nozzle is quickly moved to the center of the ink well. The time for the aerosol flow to enter the ink well and fill the ink well is captured by a high-speed camera and recorded as t1. In order to maximize the calculation accuracy and reduce the error, n ink wells are scanned in turn, and the average time to fill the ink well is calculated.

[0086] 3. Determination of solid content of aerosol flow: Select a printed substrate (such as silicon, glass, metal, PET, PI, etc.) according to actual needs, print for t1 time at a constant printing speed (1-20mm / s), obtain a single line structure, and vacuum dry it at 40℃ for 2h to obtain a completely dry 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 aerosol in the mass transfer process can be calculated as This evaporation rate can be maintained during the three-dimensional microstructure configuration to prevent evaporation from being too fast, in which case the liquid phase may dry out completely, resulting in the micrometer-nanometer solid phase being unable to be deposited on the substrate due to its light weight and lack of inertia; and evaporation from being too slow, in which case the aerosol flow contains a large amount of liquid phase components and the solid content is too low, and the printed surface becomes a fluid, which cannot provide good adhesion and conformality.

[0087] 4. Determination of the shrinkage ratio of printed microstructure units: According to actual needs, select a post-processing method to post-process the printed graphics in step 3 above. The single line obtained after post-processing is the smallest unit of three-dimensional microstructure manufacturing. Use a laser confocal microscope to scan the three-dimensional structure of the line again, 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 year-on-year; increasing the sheath gas flow in step 1 above can increase the aspect ratio h / a. The morphology of the microstructure unit can be controlled by these two methods. The shrinkage ratio of the printed structure can be calculated The deposition efficiency of the selected aerosol ink under the printing parameters is Deposition rate ρ2 = V5 / t.

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

[0089] Implementation method 5: See Figure 2 This embodiment is described. This embodiment specifically describes step S4 in the three-dimensional microstructure forming method based on aerosol printing proposed in the second embodiment above.

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

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

[0092] 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.

[0093] In actual application of this embodiment, suppose the volume of the three-dimensional microstructure to be manufactured is V6. According to the deposition efficiency, the minimum amount of ink V7=V6 / ρ1 can be calculated. To ensure the continuous generation of a stable aerosol flow, the added ink volume V8>10V7. At the same time, the printing time can also be calculated as t=V6 / ρ1. The specific manufacturing steps are: use a layer-by-layer manufacturing method to perform additive manufacturing of 3D microstructures, slice the target structure in the height direction with the height h as the basic unit, that is, divide the three-dimensional structure with a height of H into H / h two-dimensional figures with a thickness of h. For each layer of the two-dimensional figure, use Figure 2 The printing path is planned in the manner shown, and printing is performed circle by circle from the outside to the inside, with a step length of a; and the three-dimensional microstructure is printed layer by layer from bottom to top under the above-determined printing process parameters, and each layer of graphics is post-processed after printing, and then the next layer is printed. It can also be equipped with an in-situ curing device to post-process the printed graphics in real time to improve printing efficiency.

[0094] Furthermore, 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 constant temperature heating is used, the heating temperature is 150-800°C and the heating time is 10-120min; when pulse light sintering is used, the pulse amplitude is 400-800V and the pulse width is 1000-10000μs; for photocurable materials, ultraviolet light is used for post-processing, the ultraviolet light wavelength is 365-405nm, and the curing time is 5-20min.

[0095] Implementation Method 6: See Figure 1 and Figure 2 This embodiment is described. This embodiment is a practical manufacturing description of a three-dimensional microstructure forming method based on aerosol printing proposed in the above embodiment.

[0096] Fabrication of microconductive cubes using silver nanoparticle ink.

[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 20cp, functional materials of silver nanoparticles, an average particle size of 50nm, solvents of water and ethylene glycol, and additives of acrylic resin.

[0100] Take 0.2 ml of ink V1 in a plastic tube and dry it in vacuum at 40°C for 2 hours to obtain completely dried functional materials and other non-volatile substances. Use high-resolution micro-CT to scan the plastic tube and obtain the volume of the dry substance V2 = 0.016. 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 35 V. The target three-dimensional microstructure was a conductive cube with a length × width × height = 200 μm × 200 μm × 25 μm, and an accuracy of ±5 μm. Therefore, the nozzle size was selected to be 100 μm, the carrier gas flow rate was 6 sccm, and the sheath gas flow rate was 20 sccm.

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

[0104] use Figure 1 The measuring device shown measures the deposition rate of an aerosol flow, where the depth of the ink well is d = 200 μm and the radius is r = 100 μm. The volume of the ink well is V3 = πdr 2 =0.0063mm 3 . Place the above device in a closed environment with saturated vapor pressure of water and ethylene glycol to avoid evaporation of the aerosol flow after leaving the nozzle. Print under the process parameters described in step 2, turn on the atomizer and gas flow switch and keep them for 15 seconds to obtain a stable aerosol flow, then quickly move the nozzle to the center of the ink well, capture the time it takes for the aerosol flow to enter the ink well and fill the ink well with a high-speed camera, scan 36 ink wells in turn, and calculate the average time to fill the ink well.

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

[0106] Using a glass substrate, printing was performed at a constant printing speed of 10 mm / s for 8.7 seconds to obtain a single line structure, which was then vacuum dried at 40°C for 2 hours to obtain a completely dry printed pattern. The three-dimensional structure of the line was scanned using a laser confocal microscope, and its volume V4 = 0.0021 mm 3 The solid content of the aerosol flow can be calculated The evaporation rate of aerosol in the mass transfer process can be expressed as

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

[0108] The completely dried single line on the glass substrate in step 4 was heated at a constant temperature of 200°C for 10 min, and its 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 deposition efficiency of the selected aerosol ink under the printing parameters is Deposition rate ρ2 = V5 / t1 = 1.61 × 10 -4 mm 3 The printing speed and sheath gas flow rate were adjusted. When the sheath gas flow rate was 24 sccm and the printing speed was 17.6 mm / s, the minimum unit size a of the three-dimensional microstructure was 10.0 μm and the height h was 5.0 μm.

[0109] 6. Printing three-dimensional microstructures:

[0110] To ensure the continuous generation of a stable aerosol flow, 2 ml of ink was added to the ink tank. The additive manufacturing of 3D microstructures was performed using a layer-by-layer manufacturing method. The target structure was sliced ​​in the height direction with a height of 5 μm as the basic unit, that is, the 3D structure with a height of 25 μm was divided into 5 2D graphics with a thickness of 5 μm. The 2D graphics obtained in each layer were all equal in size and were 200 μm × 200 μm rectangles. Figure 2 The printing path is planned in the manner shown, and printing is performed circle by circle from the outside to the inside with a step length of 10 μm.

[0111] The three-dimensional microstructure was printed layer by layer from bottom to top in a constant temperature water bath at 18°C, with an atomization power of 35V, a carrier gas flow rate of 6sccm, a sheath gas flow rate of 24sccm, and a printing speed of 17.6mm / s. After each layer of graphics was printed, it was heated at a constant temperature of 200°C for 10 minutes, and then the next layer was printed. The actual size of the final three-dimensional micro conductive cube was length × width × height = 204.1μm × 199.8μm × 25.3μm, and the volume error was only 3.1%.

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

[0113] Embodiment 8: The three-dimensional microstructure forming method based on aerosol printing proposed in the above embodiment can be embedded in a computer-readable storage medium or a computer device to realize intelligent printing. Therefore, this embodiment provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the three-dimensional microstructure forming method based on aerosol printing described above is executed.

[0114] This embodiment also provides a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes the above-mentioned three-dimensional microstructure forming method based on aerosol printing.

[0115] A computer device provided in this embodiment, the hardware device of this part is a general model and is not shown in the form of a diagram. The system includes a processor and a memory, wherein the processor and the memory can be connected via a bus or other means. The memory is a non-transitory computer-readable storage medium that can be used to store non-transitory software programs, non-transitory computer executable programs and modules, and corresponding program instructions / modules. The processor executes various functional applications and data processing of the processor by running the non-transitory software programs, instructions and modules stored in the memory to implement the above method.

[0116] The above description is only the implementation mode of the present invention and is not limited to the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. Aerosol flow deposition rate measuring device, characterized in that, Including substrate, nozzle, high-speed camera; n micro ink wells are provided 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.

2. The aerosol flow deposition rate measuring device according to claim 1, characterized in that: The volume of the ink well is V3 = πdr 2 ; Wherein, d is the depth of the ink well and r is the radius of the ink well.

3. A three-dimensional microstructure forming method based on aerosol printing, characterized in that: The forming method is implemented based on the aerosol flow deposition rate measuring device according to claim 1 or 2, and the method is: S1: Determine the solid content φ1 of aerosol ink; S2: Determine printing process parameters according to the type of ink, and under the printing process parameters, measure 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 φ1 of the aerosol ink; S3: Determine the minimum amount of ink and printing time required for printing the three-dimensional microstructure according to the deposition efficiency ρ1 and deposition rate ρ2 of the aerosol ink; S4: Three-dimensional microstructures are manufactured using a layer-by-layer method based on the minimum amount of ink and printing time.

4. A three-dimensional microstructure forming method based on aerosol printing according to claim 3, characterized in that: S1 is specifically: S11: Select V1 volume of ink and dry it in vacuum at 40°C for 2h to obtain a completely dry functional material; S12: Measure the volume V2 of the completely dried functional material; S13: Calculate the solid content of the aerosol ink φ1=V2 / V1.

5. 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 0-50cp; the ink temperature is 5-35℃; the atomization power is 15-50V.

6. The method for forming a three-dimensional microstructure based on aerosol printing according to claim 3, characterized in that: S2 is specifically: S21: Turn on the nebulizer and gas flow switch and keep it for more than 10 seconds to obtain a stable aerosol flow; S22: quickly move the nozzle to the center of the ink well, and use a high-speed camera to capture the time when the aerosol flow enters the ink well and fills the ink well; S23: Scan n ink wells in sequence and calculate the average time t for filling the ink wells; S24: prepare a single line, scan and obtain the three-dimensional structure volume V4 of the single line, and calculate the solid content φ2=V4 / V3 of the aerosol flow; S25: Calculate the evaporation rate of aerosol during mass transfer φ3 = (φ2-φ1) / φ2; S26: post-processing the prepared single line, and using the single line after post-processing as the minimum unit for manufacturing a three-dimensional microstructure, and scanning to obtain the cross-sectional width a, height h and volume V5 of the single line; S27: Calculate the shrinkage ratio of the printed structure φ4=V5 / V4; S28: Calculate the deposition efficiency ρ1=φ1φ4=V5V2 / V1V4 and the deposition rate ρ2=V5 / t of the aerosol ink under the printing process parameters according to the shrinkage ratio.

7. A three-dimensional microstructure forming method based on aerosol printing according to claim 6, characterized in that: There are two ways to control the morphology of three-dimensional microstructure units:

1. Increasing the printing speed can reduce the cross-sectional width a and height h by the same amount; Second, increasing the sheath gas flow rate can increase the aspect ratio h / a.

8. The method for forming a three-dimensional microstructure based on aerosol printing according to claim 3, characterized in that: S4 is specifically: S41: Slicing the target three-dimensional microstructure in the height direction with the height h as the basic unit to obtain a two-dimensional figure with a thickness of h; 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.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, the three-dimensional microstructure forming method based on aerosol printing as described in claim 3 is executed.

10. 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 as described in claim 3.

Images