Time domain shaping femtosecond laser assisted aerosol multi-material additive manufacturing method

Abstract

The invention relates to a time domain shaping femtosecond laser assisted aerosol multi-material additive manufacturing method, and belongs to the technical field of additive manufacturing. According to the invention, a multi-path atomizing and mixing aerosol spraying technology is utilized to realize single material printing on the surface of a complex three-dimensional micro-system and component gradient printing of different multi-material with different physical property parameters; in-situ auxiliary sintering is carried out by using time-shaped femtosecond laser, material interface regulation and control of an electronic layer are realized, the problem of interface bonding between materials with different physical property parameters is solved, strong interface bonding of heterogeneous materials is facilitated, meanwhile, the manufacturing efficiency is greatly improved, high-temperature post-treatment is avoided, and the method is suitable for heat-labile substrates; a pumping detection light path is introduced, in the laser-assisted aerosol multi-material printing process, the interaction process of ultrafast laser and multiple materials is observed, and the ultrafast laser-assisted heterogeneous material processing mechanism is disclosed.

Description

Technical Field

[0001] The present invention relates to a method for time-domain shaped femtosecond laser-assisted aerosol multi-material additive manufacturing, belonging to the technical field of additive manufacturing. Background Art

[0002] Functional micro-devices refer to micro-devices that achieve specific functions such as signal processing, energy conversion, and biosensing through micro-nano scale design and manufacturing, and have extremely high requirements for processing capabilities and manufacturing technologies. Taking packaged antennas and passive microwave devices as examples, it is required to achieve the mutual connection and gradient printing of heterogeneous materials such as metal-ceramics in terms of materials, and ensure the forming quality such as interface bonding strength and conductivity; taking micro fuel cells as an example, it is required to achieve adjustable density of different functional layers in terms of structure, so as to carry out efficient electrochemical reactions. However, the traditional processing technology of functional micro-devices is completed through multiple process steps, and there are manufacturing problems such as complex processes, low efficiency, insufficient precision, and poor consistency, which have become the key bottlenecks restricting the performance breakthrough of the above-mentioned advanced components.

[0003] Additive manufacturing technology is a manufacturing method that constructs three-dimensional objects by layer-by-layer stacking or adding materials, and has natural advantages for the integrated near-net shaping of complex components, and has the potential to become the mainstream manufacturing technology for a new generation of functional micro-devices. However, at present, additive manufacturing technology still mainly uses continuous laser powder sintering / fusion forming methods. When forming multi-materials with large physical property differences, defects such as cracks, pores, and uneven distribution are likely to occur, resulting in insufficient connection strength of components and poor forming quality. Femtosecond laser processing has strong non-linear and non-equilibrium characteristics, which can make the instantaneous processing characteristics of various materials converge, and form high-quality and high-strength interconnections of heterogeneous interfaces. Therefore, the development of precision additive manufacturing technology based on femtosecond lasers is expected to solve the above-mentioned multi-material processing bottleneck problems and achieve high-quality integrated molding of functional micro-devices. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem of high-quality integrated molding of multi-materials of the above-mentioned functional micro-devices, and to achieve adjustable structure density and variable material composition gradient during the printing process. The present invention proposes a method for time-domain shaped femtosecond laser-assisted aerosol multi-material additive manufacturing, which uses a multi-channel atomized mixing aerosol spraying technology to achieve gradient printing of multi-material components on the surface of complex three-dimensional functional micro-devices; uses time-shaped femtosecond lasers for in-situ assisted sintering to achieve adjustable structure density; at the same time, through material interface regulation at the electronic level, solves the interface bonding problem between materials with very different physical property parameters, helps to achieve strong interface bonding of heterogeneous materials, greatly improves the manufacturing efficiency, and avoids high-temperature post-treatment, and is applicable to heat-sensitive substrates.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A time-domain shaped femtosecond laser-assisted aerosol multi-material additive manufacturing method, characterized in that: while the aerosol is jet-deposited on the surface of the substrate, in-situ assisted sintering is carried out using a time-shaped femtosecond laser. Electrons and phonons collide with each other and generate energy coupling, increasing the degree of interatomic bonding and remelting and connecting the nanoparticles. Through the combined modulation of the femtosecond laser pulse sequence, flexible control at the electron level is further realized to solve the interfacial bonding problem between materials with very different physical properties.

[0007] The above-mentioned time-domain shaped femtosecond laser-assisted aerosol multi-material additive manufacturing method is characterized in that: the repetition frequency of the femtosecond laser is greater than 200 kHz, and the laser power is less than 5 W.

[0008] The device of the above method is characterized in that: it includes a femtosecond laser, a processing laser, a beam splitter, a movable mirror, a mirror, a plano-convex lens, a gas cylinder, a gas path, an ultrasonic atomization module, a mixed gas path, a nozzle, a processing substrate and a displacement stage; the femtosecond laser generates a processing laser, which reaches the beam splitter after passing through the beam splitter. The beam splitter divides the laser into two beams, which are reflected by the movable mirror and converge again through the beam splitter to form a time-domain shaped double-pulse laser, and then passes through the mirror and the plano-convex lens and is focused on the upper surface of the processing substrate; for the aerosol printing part, the inert gas is sent out from the gas cylinder as the carrier gas, and the carrier gas enters the ultrasonic atomization module through the gas path. The ink material in the ultrasonic atomization module generates aerosol particles by ultrasonic vibration. The carrier gas entangles the atomized ink to form an aerosol flow. The aerosol flows of each path converge and mix evenly in the mixed gas path and are sprayed and deposited on the upper surface of the processing substrate through the nozzle. The movement of the processed sample is realized through the displacement stage, and single-material printing or multi-material gradient printing and multi-material layer printing of the aerosol are realized on the sample surface.

[0009] The device is characterized in that: it further includes a CCD high-resolution camera, an observation light, a lighting lamp, a beam splitter and a plano-convex lens; the lighting lamp generates an observation light, which passes through two beam splitters and the plano-convex lens in sequence and is focused on the surface of the processed sample, and then the observation light returns along the original path and enters the CCD high-resolution camera.

[0010] The device is characterized in that: there are multiple ultrasonic atomization modules, and the ultrasonic atomization modules are placed in parallel, and the aerosol flows formed by multiple materials converge and mix evenly in the mixed gas path.

[0011] The method for the device to realize multi-material composition gradient printing and multi-level material structure density control includes the following steps:

[0012] Step 1: Adjust the femtosecond laser light field to ensure that the light field energy is Gaussian intensity distribution;

[0013] Step 2: Adjust the femtosecond laser parameters to ensure that the output light source is a high-repetition femtosecond laser. Adjust the femtosecond laser system from the light source, and adjust the average laser power of the processing optical path; adjust the interval of the femtosecond laser pulse train to achieve flexible control at the electronic level, increase the degree of atomic bonding, and help to realize the remelting and connection of nanoparticles;

[0014] Step 3: Adjust the level of the processing platform and determine the processing position of the light spot on the substrate;

[0015] Step 4: Place the aerosol ink in their respective atomization modules, turn on the ultrasonic atomization device, and use the principle of ultrasonic vibration to fully atomize the ink to form an aerosol in the atomization chamber, and ensure that there is no bottom precipitation;

[0016] Step 5: Open the gas cylinder, introduce an inert gas as the carrier gas, and make the carrier gas carry the aerosol ink in each atomization module into the gas path and mix evenly in the gas path;

[0017] Step 6: Adjust the position and angle of the aerosol nozzle so that the nozzle is 1-2 mm away from the substrate, and the carrier gas jet is aligned with the substrate and coincides with the light spot position;

[0018] During the processing, always keep the aerosol nozzle fixed, the aerosol carrier gas jet coincides with the light spot, and the sample is processed by moving the processing table; by adjusting the flow rate of each gas path through the flow valve, the proportion control of each material component can be achieved; continuously adjusting the flow valve of each gas path during the processing can achieve multi-material composition gradient printing; changing the laser power and repetition rate during the processing can achieve the control of the density of multi-level material structures; femtosecond laser has the advantage of electronic dynamic control. Under the action of femtosecond laser irradiation, heterogeneous materials undergo plasma phase transformation, and the electron-phonon interaction collides violently, resulting in local atomic rearrangement and strong bonding, which significantly improves the mechanical properties of the printed materials;

[0019] Step 8: During the processing, use the pump-probe optical path to capture the plasma eruption intensity and luminescence brightness to analyze the evolution of the plasma luminescence intensity and spectrum over time, providing a theoretical and data basis for revealing the action mechanism of heterogeneous materials and establishing a multi-material cladding model;

[0020] Step 9: After the processing is completed, first turn off the mechanical switch of the aerosol nozzle, then turn off the gas cylinder, and finally turn off the femtosecond laser.

[0021] Beneficial effects:

[0022] 1. A method for time-domain shaped femtosecond laser-assisted aerosol multi-material additive manufacturing disclosed by the present invention adopts an additive manufacturing method of multi-channel aerosol mixing injection. An inert carrier gas wraps nano-scale ink materials to form aerosol particles, enabling uniform mixing of multi-materials with very different physical properties. Compared with processing methods such as inkjet printing and SLM selective sintering, the process is simpler, the heterogeneous material mixing is more uniform, the material universality is wider, and it has advantages in processing multi-material systems with very different physical properties.

[0023] 2. A method for time-domain shaped femtosecond laser-assisted aerosol multi-material additive manufacturing disclosed by the present invention can control the proportion of each material component in the jet by adjusting the gas flow rate of each gas path, realizing compositional gradient printing with high adjustment accuracy.

[0024] 3. A method for time-domain shaped femtosecond laser-assisted aerosol multi-material additive manufacturing disclosed by the present invention uses time-domain shaped laser-assisted in-situ sintering. The focus of the femtosecond laser coincides with the printing point of the aerosol nozzle to achieve precise position-assisted printing. Different from single aerosol injection, the present invention realizes strong interfacial bonding of multi-materials with very different physical properties through the regulation of the electron density and electron energy of the mixed multi-materials by femtosecond laser, and realizes multi-material phase change regulation at the electron level.

[0025] 4. A method for time-domain shaped femtosecond laser-assisted aerosol multi-material additive manufacturing disclosed by the present invention uses laser-assisted in-situ sintering to replace the traditional heating plate during aerosol printing. Due to the non-linear absorption characteristics of femtosecond laser, the thermal effect is greatly reduced, which can be used for substrates that are not resistant to high temperatures, increasing the universality of the substrates; at the same time, the non-linear absorption characteristics of femtosecond laser can reduce the thermal stress on the materials, realizing high-precision and high-quality additive manufacturing of multi-materials with very different physical properties.

[0026] 5. A method for time-domain shaped femtosecond laser-assisted aerosol multi-material additive manufacturing disclosed by the present invention can realize the regulation of the structural density of multi-level materials in terms of structure by changing the laser parameters; in terms of materials, it can realize the compositional gradient printing of multi-materials on the surface of complex three-dimensional functional micro-devices.

[0027] 6. A method for time-domain shaped femtosecond laser-assisted aerosol multi-material additive manufacturing disclosed by the present invention introduces an observation optical path to in-situ observe the process of laser-assisted aerosol multi-material printing. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the multi-material printing system of the present invention;

[0029] Figure 2 It is a schematic diagram of the manufacturing of the fuel cell functional layer of the present invention;

[0030] Figure 3 It is a schematic diagram of the manufacturing of the micro-system of the present invention;

[0031] Figure 4 Schematic diagram of the packaged chip of the present invention;

[0032] Among them, 1 - femtosecond laser, 2 - processing laser, 3 - beam splitter, 4 - movable mirror, 5 - mirror, 6 - mirror, 7 - beam splitter, 8 - plano-convex lens, 9 - CCD high-resolution camera, 10 - observation light, 11 - illumination lamp, 12 - beam splitter, 13 - gas cylinder, 14 - gas path, 15 - ultrasonic atomization module, 16 - mixed gas path, 17 - nozzle, 18 - processing substrate, 19 - displacement stage, 20 - connector, 21 - anode layer, 22 - electrolyte layer, 23 - cathode layer, 24 - ceramic substrate, 25 - Ag circuit, 26 - packaged chip, 27 - multi-material gradient printing layer, 28 - gradient printing path, 29 - single-material printing layer, 30 - sidewall Ag circuit, 31 - PE packaging layer, 32 - SU-8 photoresist, 33 - Au interdigital electrode, 34 - ceramic substrate layer. Specific embodiments

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] Name Display function Example 1 Adjustable structural density Example 2 Variable material composition gradient

[0035] Example 1 (Adjustable structural density)

[0036] As Figure 1As shown in the figure, the femtosecond laser-assisted aerosol multi-material additive manufacturing method of Embodiment 1 disclosed in this embodiment includes a femtosecond laser 1, a processing laser 2, a beam splitter 3, a movable mirror 4, a mirror 5, a mirror 6, a beam splitter 7, a plano-convex lens 8, a CCD high-resolution camera 9, an observation light 10, a lighting lamp 11, a beam splitter 12, a gas cylinder 13, a gas path 14, an ultrasonic atomization module 15, a mixed gas path 16, a nozzle 17, a processing substrate 18, and a displacement stage 19. In the processing optical path part, the femtosecond laser 1 generates the processing laser 2, which reaches the beam splitter 3. The beam splitter 3 divides the laser into two beams, which are reflected by the movable mirror 4 and the mirror 5, and then converge again through the beam splitter 3 to form a time-domain shaped double-pulse laser, which is then focused on the upper surface of the processing substrate 18 through the mirror 6, the beam splitter 7, and the plano-convex lens 8; in the aerosol printing part, the inert gas is passed out from the gas cylinder 13 as the carrier gas. The carrier gas enters the ultrasonic atomization module 15 through the gas path 14. The ink material in the ultrasonic atomization module 15 generates aerosol particles by ultrasonic vibration. The carrier gas entrains the atomized ink to form an aerosol flow. Each aerosol flow converges and mixes evenly in the mixed gas path 16 and is sprayed and deposited on the upper surface of the processing substrate 18 through the nozzle 17. The processing sample moves through the displacement stage 19 to achieve this; in the observation optical path part, the observation light 10 is generated by the lighting lamp 11, and is successively focused on the surface of the processing sample through the beam splitter 12, the beam splitter 7, and the plano-convex lens 8. Then the observation light returns along the original path and enters the CCD high-resolution camera 9.

[0037] At the same time, the femtosecond laser needs to use a high repetition rate, with a repetition rate greater than 200 kHz, so as to ensure that a sufficient number of free electrons are excited in the multi-material in a very short time, and strong bonding and welding of the interfaces of heterogeneous materials are achieved through electronic dynamic regulation. In addition, it is necessary to ensure that the laser power is less than 5 W. Excessive energy will cause material ablation and removal, and multi-material additive manufacturing cannot be formed.

[0038] In this example, a glass sheet is selected as the processing substrate. The specific steps of this example are as follows:

[0039] (1) The optical path system adopted in the present invention is as Figure 1 shown. The laser at the light outlet has a pulse width of 150 fs and a wavelength of 1030 nm. The femtosecond laser optical path is collimated and adjusted, and the light field is adjusted to ensure that the light field energy is in a Gaussian intensity distribution;

[0040] (2) Adjust the femtosecond laser parameters, use a repetition rate of 800 kHz to ensure that the emitted light source is a high-repetition-rate femtosecond laser, and adjust the femtosecond laser system from the light source to ensure that the average laser power of the processing optical path is 1 - 2 W;

[0041] (3) Adjust the level of the processing platform, use a 150 mm plano-convex lens, and determine the processing position of the light spot on the substrate;

[0042] (4) Place the nanoparticle dispersion liquids of the three functional layer materials in the ultrasonic atomization module, turn on the ultrasonic atomization device for 10 - 15 minutes, and utilize the principle of ultrasonic vibration to fully atomize the ink, forming an aerosol in the atomization chamber and ensuring no bottom precipitation;

[0043] (5) Open the gas cylinder, with a gas pressure of 0.1 - 0.2 MPa, introduce an inert gas as the carrier gas, and the gas flow rate is 10 - 30 SCCM, so that the carrier gas carries the aerosol ink in the ultrasonic atomization module into the gas path;

[0044] (6) Adjust the position and angle of the aerosol nozzle so that the nozzle is 1 - 2 mm away from the substrate, and the carrier gas jet is aligned with the substrate and coincides with the position of the light spot;

[0045] (7) During the processing, always keep the aerosol nozzle fixed, the aerosol carrier gas jet coincides with the light spot, and realize sample processing by moving the processing table, with the moving speed of the processing table being 1 - 2 mm / s;

[0046] (8) During the processing, use the observation optical path to in - situ observe the laser - assisted aerosol multi - material printing process; regulate the laser power, control the porosity of the functional layer, and print the cathode layer 23 (porous fuel electrode reaction layer), electrolyte layer 22 (dense functional layer), and anode layer 21 (porous air electrode reaction layer) successively.

[0047] (9) After the processing is completed, first turn off the mechanical switch of the aerosol nozzle, then turn off the gas cylinder, and finally turn off the femtosecond laser. As Figure 2 shown is the schematic diagram of the manufacturing of the fuel cell functional layer in Example 1. The present invention can realize adjustable porosity of each functional layer and is used for the integrated manufacturing of the fuel cell functional layer. Place the pre - 3D - printed connector 20 on the displacement stage 19, open the aerosol carrier gas path, and can successively print the cathode layer 23 (porous fuel electrode reaction layer), electrolyte layer 22 (dense functional layer), and anode layer 21 (porous air electrode reaction layer) layer by layer on the surface of the substrate. By changing the femtosecond laser power, the density of nanoparticles can be regulated, which helps to enhance the reaction efficiency of the fuel cell.

[0048] Example 2 (Variable material composition gradient)

[0049] As Figure 1As shown in the figure, the femtosecond laser-assisted aerosol multi-material additive manufacturing method with time-domain shaping disclosed in Embodiment 2 of this embodiment includes a femtosecond laser 1, a processing laser 2, a beam splitter 3, a movable mirror 4, a mirror 5, a mirror 6, a beam splitter 7, a plano-convex lens 8, a CCD high-resolution camera 9, an observation light 10, a lighting lamp 11, a beam splitter 12, a gas cylinder 13, a gas path 14, an ultrasonic atomization module 15, a mixed gas path 16, a nozzle 17, a processing substrate 18, and a displacement stage 19. In the processing optical path part, the femtosecond laser 1 generates a processing laser 2, which reaches the beam splitter 3. The beam splitter 3 divides the laser into two beams, which are reflected by the movable mirror 4 and the mirror 5, and then converge again through the beam splitter 3 to form a time-domain shaped double-pulse laser, and then passes through the mirror 6, the beam splitter 7, and the plano-convex lens 8 to be focused on the upper surface of the processing substrate 18; in the aerosol printing part, the inert gas is passed out from the gas cylinder 13 as the carrier gas. The carrier gas enters the ultrasonic atomization module 15 through the gas path 14. The ink material in the ultrasonic atomization module 15 generates aerosol particles by ultrasonic vibration. The carrier gas entrains the atomized ink to form an aerosol flow. The aerosol flows from each path converge and mix evenly in the mixed gas path 16 and are ejected and deposited on the upper surface of the processing substrate 18 through the nozzle 17. The processed sample moves through the displacement stage 19 to achieve this; in the observation optical path part, the observation light 10 is generated by the lighting lamp 11, passes through the beam splitter 12, the beam splitter 7, and the plano-convex lens 8 in sequence and is focused on the surface of the processed sample, and then the observation light returns along the original path and enters the CCD high-resolution camera 9.

[0050] At the same time, the femtosecond laser needs to use a high repetition rate, and the repetition rate is greater than 200 kHz to ensure that a sufficient number of free electrons are excited in the multi-material in a very short time, and strong bonding and welding of the interfaces of heterogeneous materials are achieved through electronic dynamic regulation. In addition, it is necessary to ensure that the laser power is less than 5 W. Excessive energy will cause material ablation and removal, and multi-material additive manufacturing cannot be formed.

[0051] In this example, the dispersion solutions with silver (Ag) nanoparticles, aluminum oxide (Al 2 O 3 ) nanoparticles, copper oxide nanoparticles, polyethylene (PE) nanoparticles, SU-8 photoresist, and gold (Au) nanoparticles as solutes are used as the atomized inks respectively. The specific steps of this example are as follows:

[0052] (1) The optical path system adopted in the present invention is as Figure 1 shown. The laser at the light outlet has a pulse width of 150 fs and a wavelength of 1030 nm. The femtosecond laser optical path is collimated and adjusted, and the light field is adjusted to ensure that the light field energy has a Gaussian intensity distribution;

[0053] (2) Adjust the femtosecond laser parameters, use a repetition rate of 800 kHz to ensure that the emitted light source is a high-repetition-rate femtosecond laser, and adjust the femtosecond laser system from the light source to ensure that the average laser power of the processing optical path is 1-2 W;

[0054] (3) Adjust the level of the processing platform, use a 150 mm plano-convex lens, and determine the processing position of the light spot on the substrate;

[0055] (4) Place the three dispersions of silver nanoparticles, alumina nanoparticles, and copper oxide nanoparticles in their respective atomization modules, turn on the ultrasonic atomization device for 10 - 15 minutes, utilize the principle of ultrasonic vibration to fully atomize the ink, form an aerosol in the atomization chamber, and ensure no bottom precipitation;

[0056] (5) Open the gas cylinder, with a gas pressure of 0.1 - 0.2 MPa, introduce an inert gas as the carrier gas, and the gas flow rate is 10 - 30 SCCM. Make the carrier gas carry the aerosol ink in each atomization module into the gas path and mix evenly in the gas path;

[0057] (6) Adjust the position and angle of the aerosol nozzle so that the nozzle is 1 - 2 mm away from the substrate, and the carrier gas jet is aligned with the substrate and coincides with the light spot position;

[0058] (7) During the processing, always keep the aerosol nozzle fixed, the aerosol carrier gas jet coincides with the light spot, and realize sample processing by moving the processing table. The moving speed of the processing table is 1 - 2 mm / s; by adjusting the flow rate of each gas path through the flow valve, the proportion control of each material component can be realized; continuously adjusting the flow valves of each gas path during the processing can realize compositional gradient printing;

[0059] (8) During the processing, use the observation optical path to in-situ observe the process of laser-assisted aerosol multi-material printing;

[0060] (9) After the processing is completed, first turn off the mechanical switch of the aerosol nozzle, then turn off the gas cylinder, and finally turn off the femtosecond laser.

[0061] As Figure 3 shown is the schematic diagram of the micro-system manufacturing in Example 2. The present invention can realize micro-system manufacturing on the surface of a three-dimensional substrate. Place the pre-3D printed ceramic substrate 24 on the displacement table 19, open the carrier gas gas path of the silver nanoparticle aerosol, and Ag circuits 25 can be printed on the surface of the substrate and precision Ag circuits 30 can be printed on the side walls. The printing area is as shown in the single-material printing layer 29. No high-temperature post-treatment is required, avoiding damage to non-heat-resistant parts; due to the regulation effect of the femtosecond laser on Ag nanoparticles, the adhesion between Ag and the ceramic substrate and the interfacial bonding strength are effectively enhanced.

[0062] To further illustrate the multi-material gradient printing ability, as Figure 3The following is a schematic diagram of the micro-system manufacturing in Example 2. The pre-3D printed ceramic substrate 24 is placed on the displacement stage 19. By adjusting the flow rates of each carrier gas, a multi-material gradient printing layer 27 can be achieved, and the printing path is like the gradient printing path 28. Through the multi-material gradient printing technology, effective bonding between materials with large differences in physical property parameters can be realized, which has a significant effect on improving the interface strength between metal and ceramic.

[0063] To further illustrate the 3D packaging capability, as Figure 4 The following is a schematic diagram of the packaged chip in Example 2. The carrier gas material is adjusted, the Au gas path is opened, and the Au interdigital electrodes 33 are sprayed on the ceramic matrix layer 34; then the Au gas path is closed, the SU-8 photoresist gas path is opened, and the SU-8 photoresist 32 is sprayed at the gaps of the Au interdigital electrodes; finally, the SU-8 photoresist gas path is closed, the PE gas path is opened, and the PE packaging layer 31 is sprayed on the upper layer to complete the integrated additive manufacturing of the packaged chip.

[0064] The performance of the finished functional micro-device manufactured in Example 2 is tested. The micro-circuit is conductive, the interface between the circuit and the substrate is firmly bonded, and at the same time, the processing efficiency is much higher than the traditional post-treatment method in a high-temperature furnace, which proves the beneficial effects of the present invention.

[0065] The above specific description further details the purpose, technical solution and beneficial effects of the invention. It should be understood that the above is only a specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A time-domain shaping femtosecond laser-assisted aerosol multi-material additive manufacturing method, characterized in that: While the aerosol jet is deposited on the surface of the substrate, a time-shaped femtosecond laser is used for in-situ assisted sintering. The electrons and phonons collide with each other and generate energy coupling, which increases the degree of interatomic bonds and causes the nanoparticles to be remelted and connected. Through the combined modulation of the femtosecond laser pulse sequence, flexible regulation at the electronic level is further achieved to solve the interface bonding problem between materials with very different physical properties.

2. A time-domain shaping femtosecond laser-assisted aerosol multi-material additive manufacturing method as claimed in claim 1, characterized in that: The repetition frequency of femtosecond laser is greater than 200kHz and the laser power is less than 5w.

3. A device for implementing the method according to claims 1 to 2, characterized in that: It includes a femtosecond laser, a processing laser, a beam splitter, a movable reflector, a reflector, a plano-convex lens, a gas cylinder, a gas path, an ultrasonic atomization module, a mixing gas path, a nozzle, a processing substrate and a translation stage; the femtosecond laser generates a processing laser, which reaches the beam splitter through the beam splitter, and the beam splitter divides the laser into two beams, which are reflected by the movable reflector and converged again through the beam splitter to form a double-pulse laser with time domain shaping, and then focused on the upper surface of the processing substrate through the reflector and the plano-convex lens; in the aerosol printing part, the gas cylinder passes an inert gas as a carrier gas flow, and the carrier gas flow enters the ultrasonic atomization module through the gas path, the ink material in the ultrasonic atomization module generates aerosol particles by ultrasonic vibration, and the carrier gas flow entrains the atomized ink to form an aerosol gas flow, and the various aerosol gas flows converge and mix evenly in the mixing gas path, and are deposited on the upper surface of the processing substrate through the nozzle, and the processing sample movement is realized through the translation stage, and aerosol single material printing or multi-material gradient printing and multi-material layered printing are realized on the sample surface.

4. The device according to claim 3, characterized in that: It also includes a CCD high-resolution camera, observation light, an illuminator, a beam splitter and a plano-convex lens; the illuminator generates observation light, which passes through two beam splitters and plano-convex lenses in sequence and is focused on the surface of the processed sample, and then the observation light returns along the original path and enters the CCD high-resolution camera.

5. The device according to claim 3, characterized in that: There are multiple ultrasonic atomization modules, each of which is placed in parallel, and aerosol airflows formed by multiple materials converge in the mixed air path and are evenly mixed.

6. A method for realizing multi-material composition gradient printing and multi-layer material structure density control using the device as claimed in claim 3, 4 or 5, comprising the following steps: Step 1: Adjust the femtosecond laser light field to ensure that the light field energy has a Gaussian intensity distribution; Step 2: Adjust the femtosecond laser parameters to ensure that the output light source is a high-repetition-rate femtosecond laser, adjust the femtosecond laser system from the light source, and adjust the average laser power of the processing optical path; adjust the interval of the femtosecond laser pulse sequence to achieve flexible regulation at the electronic level, increase the interatomic bond and degree, and help achieve the remelting connection of nanoparticles; Step 3: Adjust the processing platform level and determine the processing position of the light spot on the substrate; Step 4: Place the aerosol ink in each atomization module, turn on the ultrasonic atomization device, and use the ultrasonic vibration principle to fully atomize the ink to form an aerosol in the atomization chamber, and ensure that there is no bottom precipitation; Step 5: Open the gas cylinder and introduce inert gas as carrier gas flow, so that the carrier gas flow carries the aerosol ink in each atomization module into the gas path and mixes them evenly in the gas path; Step 6: Adjust the position and angle of the aerosol nozzle so that the nozzle is 1-2 mm away from the substrate, and the carrier gas jet is aimed at the substrate and coincides with the spot position; Step 7: During the processing, the aerosol nozzle is always kept fixed, the aerosol carrier gas jet coincides with the light spot, and the sample processing is realized by moving the processing table; the flow rate of each gas path is adjusted by the flow valve to realize the proportion control of each material component; the flow valve of each gas path is continuously adjusted during the processing to realize the gradient printing of multi-material components; the laser power and repetition rate are changed during the processing to realize the density control of multi-level material structure; femtosecond laser has the advantage of electronic dynamic control, and heterogeneous materials undergo plasma phase transition under the irradiation of femtosecond laser, electrons and phonons collide violently with each other, local atoms are rearranged and strong bonds and effects are generated, so that the mechanical properties of the printed materials are significantly improved; Step 8: During the processing, the pump-probe optical path is used to capture the plasma ejection intensity and luminescence brightness to analyze the evolution of plasma luminescence intensity and spectrum over time, providing a theoretical and data basis for revealing the mechanism of heterogeneous materials and establishing a multi-material cladding model; Step 9: After the processing is completed, first turn off the mechanical switch of the aerosol nozzle, then turn off the gas cylinder, and finally turn off the femtosecond laser.

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