An efficient 3D printing device and method for gradient materials based on spiral channels

Abstract

The present invention relates to the field of 3D printing, and particularly to a high-efficiency 3D printing device and method for gradient materials based on a spiral flow channel, which are used to solve the technical problem that in traditional 3D printing technologies, it is impossible to achieve a complex gradient distribution of the particle size of reinforcing particles in composite materials or the pore size of porous materials. The printing device includes an additive manufacturing forming platform, a spiral separation and assembly system, a material supply system, and a computer control system. Through the inertial microfluidic particle manipulation mechanism of the spiral separation channel in the spiral separation and assembly system, combined with the design combination of the digital assembly extrusion head and the optimization of printing process parameters, a complex gradient distribution of reinforcing particles or sacrificial template particles in the matrix material can be achieved, which has great application potential in the fields of materials and engineering.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing technology, and particularly to an efficient 3D printing device and method for gradient materials based on a spiral flow channel. Background Art

[0002] Functionally graded materials refer to a new type of material with special functions. Elements such as the chemical composition, microstructure, and porosity of the material continuously or quasi-continuously change from one side to the other along the thickness or length of the material, so that its physical, chemical, and other properties present gradient changes according to the design requirements. The biggest feature of this material is that there is no obvious interface inside the material, and the composition, shape, structure, performance, and function all show a gradual change form. Compared with homogeneous composite materials, functionally graded materials have stronger designability. The expected composition distribution form can be designed according to requirements, so that the performance and function of the material change with the change of the material position, and the microstructure at its interface shows a continuous gradual change, eliminating the performance mutation and mismatch of different materials. The traditional preparation methods of functionally graded materials include powder metallurgy, plasma spraying, chemical vapor deposition, self-propagating high-temperature synthesis, electro-deposition, and centrifugal casting, etc. Although the above preparation methods have many advantages, they are usually restricted by many factors in practical applications.

[0003] In recent years, the rapid development of 3D printing technology has provided a new technical solution for the manufacturing of functionally graded materials and structures. For example, technologies such as directed energy deposition, laser cladding, and polymer jetting can be used to realize the manufacturing of materials with a gradient distribution of chemical components. However, when manufacturing composite materials, there is no good solution for the precise and designable gradient distribution of the internal reinforcing particle sizes. Summary of the Invention

[0004] Aiming at the lack of solutions for inducing complex and precise gradient distributions of reinforcing particles in composite materials in current traditional manufacturing methods and existing 3D printing technologies, the present invention provides an efficient 3D printing device for gradient materials based on a spiral flow channel. Furthermore, an efficient 3D printing method for gradient materials based on a spiral flow channel is provided.

[0005] To solve the above technical problems, the technical solution of the present invention is specifically as follows:

[0006] An efficient 3D printing device for gradient materials based on a spiral flow channel, comprising:

[0007] An additive manufacturing forming platform 1, as a basic component of the 3D printing device, whose built-in motion system enables the additive manufacturing forming platform 1 to move in a plane and in the vertical direction. When the reinforced particle composite material with a gradient particle size distribution is extruded by the spiral separation and assembly system 2, combined with the movement of the additive manufacturing forming platform 1, the cumulative forming of the gradient particle size reinforced material can be realized;

[0008] The spiral separation and assembly system 2, as the core functional component of the 3D printing device of the present invention, can transport the printing ink from the material supply inlet 28 into the spiral separation and assembly system 2. After that, particles with different particle sizes in the printing ink show a gradient distribution in the cross-sectional direction of the spiral separation channel 21. Combining with the material temporary storage cylinder 23 and the digital assembly extrusion head 26 can achieve a designed gradient pattern distribution of particles with different particle sizes in the printing channel.

[0009] The material supply system 3 is used to hold and transport the printing ink with a rich particle size distribution, and transports the printing ink to the spiral separation and assembly system 2 at a fixed time and speed through the material supply channel 31.

[0010] The computer control system 4, as the control center of the entire 3D printing device, decomposes the printing process flow according to the three-dimensional model of the particle-reinforced composite material or porous material with a gradient particle size distribution, is used to control the working processes of the additive manufacturing forming platform 1, the spiral separation and assembly system 2, and the material supply system 3, and optimizes the optimal process parameters.

[0011] Further, the additive manufacturing forming platform 1 includes:

[0012] The additive manufacturing forming platform software system is integrated in the computer control system 4 and is used to control the movement of the additive manufacturing forming platform hardware system in the horizontal plane and the vertical direction.

[0013] The additive manufacturing forming platform hardware system is the physical basis for the additive manufacturing forming platform 1 to achieve motion programming. The movement of the additive manufacturing forming platform hardware system in three-dimensional space can realize the controllable layer-by-layer deposition and cumulative forming of the material extruded by the spiral separation and assembly system 2.

[0014] Further, the spiral separation and assembly system 2 includes:

[0015] The spiral separation channel 21, as the core component of the spiral separation and assembly system 2, utilizes the mechanism of inertial microfluidics to manipulate particles and benefits from the unique size-dependent characteristics of secondary flow and inertial lift force, which can promote the particles in the printing ink to show a gradient distribution according to particle size. Then, through the material separation and supply outlet 28, the printing ink containing different particle size ranges is separated and transported into the material temporary storage cylinder 23.

[0016] The separation and supply channel 22 is connected to the material separation outlet 29 of the spiral separation channel 21 at the upper end and the material temporary storage cylinder 23 at the lower end, and can transport the separated printing ink containing different particle size ranges to the material temporary storage cylinder 23 for transfer and storage.

[0017] The material temporary storage cylinder 23 temporarily stores the separated printing ink containing particles within a certain particle size range through the separation and conveying channel 22;

[0018] The assembled conveying hose 24 is connected to the material temporary storage cylinder 23 at the upper end and the digital assembly extrusion head 26 at the lower end, and further conveys the separated printing ink to the corresponding extrusion head in the digital assembly extrusion head 26. In addition, the material of the assembled conveying hose 24 is a soft material, which can achieve a certain amount of torsional deformation, facilitating the position adjustment and reassembly of the extrusion head in the digital assembly extrusion head 26;

[0019] The rotating device 25 is integrated with the digital assembly extrusion head 26 and can drive the digital assembly extrusion head 26 to rotate clockwise by 0 - 90° and counterclockwise by 0 - 90° during the printing process;

[0020] The digital assembly extrusion head 26 conveys the separated materials containing particles within different particle size ranges to the corresponding extrusion heads in the digital assembly extrusion head 26, and automatically assembles the extrusion heads in different arrangements according to needs, thereby realizing an adjustable and designable particle size assembly distribution of the particles in the composite material;

[0021] The light - curing system 27 is used to cure the printing ink extruded from the digital assembly extrusion head 26 in real - time and in - situ, and fix the particle size distribution of the particles in the printing channel;

[0022] The material conveying inlet 28 conveys the printing ink with a rich particle size distribution from the material conveying inlet 28 to the spiral separation channel 21;

[0023] The material separation outlet 29 separates the printing ink containing different particle size ranges and temporarily stores it in the material temporary storage cylinder 23.

[0024] Furthermore, the material supply system 3 includes:

[0025] The material conveying channel 31 connects the material supply system 3 and the spiral separation and assembly system 2, and can convey the printing ink with a rich particle size distribution from the material supply system 3 to the spiral separation and assembly system 2;

[0026] The material pumping device 32 controls the conveying time and conveying speed of the unseparated printing ink from the material supply system 3 to the spiral separation and assembly system 2;

[0027] The storage tank 33 is used to store and hold the unseparated printing ink;

[0028] The anti - sedimentation stirring device 34 prevents the sedimentation of particles in the printing ink in the storage tank 33 and rotates and stirs at a fixed time and speed.

[0029] Among them, two or more of the material supply systems 3 can be provided as needed.

[0030] Furthermore, the computer control system 4 includes:

[0031] An additive manufacturing module for controlling the workflow and moving speed of the additive manufacturing platform during the printing process;

[0032] A print head rotation and assembly module for controlling the arrangement, assembly and rotational movement of the print head in real time during printing to obtain an ideal particle size distribution;

[0033] A material delivery module for controlling the delivery time and delivery speed of the unseparated printing ink.

[0034] Additionally, a high-efficiency 3D printing method for gradient materials based on a spiral flow channel includes:

[0035] S101, Material preparation

[0036] Printing ink matrix materials: 60 - 85 wt% of polyurethane acrylate, 1 - 5 wt% of photoinitiator 1 - hydroxycyclohexyl phenyl ketone, 18 - 25 wt% of 1,6 - 2 diol diacrylate;

[0037] Reinforcing particles: one or a combination of several of boron nitride, aluminum nitride, silicon nitride, silicon carbide, aluminum oxide, beryllium oxide, magnesium oxide, zinc oxide, silicon oxide, graphite, starch, carbon powder, ammonium bicarbonate, polymethyl methacrylate microspheres, polystyrene microspheres;

[0038] Sacrificial template particles: The sacrificial template particles are easily removable materials, such as granular sugar particles, salt particles, iodine particles, etc., which can be removed through post - treatment processes (heating, soaking);

[0039] Among them, the reinforcing particles are used to enhance the mechanical or physical properties of the matrix material;

[0040] Among them, the sacrificial template particles are used to manufacture porous materials;

[0041] Among them, the particle size distribution of the reinforcing particles and the sacrificial template particles is 2 - 200 μm;

[0042] Add 5 - 30 vol% of the reinforcing particles or the sacrificial template particles to the matrix material for mixing, stir evenly, and set aside;

[0043] S102, Additive manufacturing of gradient distribution materials of reinforcing particle diameters, specifically including:

[0044] Step 1: Construction and decomposition of the three-dimensional model. Select appropriate reinforcing particles or sacrificial template particles according to functional requirements, and determine the distribution pattern of the particle size of the reinforcing particles or sacrificial template particles and the macroscopic geometric parameters of the model.

[0045] Step 2: Decomposition of the hardware system working process and programming of process parameters. Based on the distribution information of the particle size of the reinforcing particles or sacrificial template particles and the macroscopic geometric parameters of the model determined in Step 1, determine the printing path, printing speed, and Z-axis downward movement thickness of the additive manufacturing forming platform 1; the number of turns of the spiral separation channel 21 in the spiral separation and assembly system 2, the rotation direction and rotation speed of the digital rotation device 25, the real-time adjustment sequence and assembly type of the digital assembly extrusion head 26; and the conveying speed of the printing ink of the material pumping device 32 in the material supply system 3.

[0046] Among them, the moving speed of the additive manufacturing forming platform 1 in the X-Y plane is 1 mm / s to 20 mm / s.

[0047] Among them, the thickness of the Z-axis downward movement of one layer thickness during the printing and forming process of the additive manufacturing forming platform 1 is 0.1 - 0.7 mm.

[0048] Among them, the number of turns of the spiral separation channel 21 in the spiral separation and assembly system 2 is 0 - 20 turns.

[0049] Among them, the rotation speed of the digital rotation device 25 in the spiral separation and assembly system 2 is 0.1 - 2.5 rpm.

[0050] Among them, the conveying speed of the printing ink of the material pumping device 32 is 40 ml / min - 400 ml / min.

[0051] Step 3: Set the preferred working process, printing path, and printing process, and load the printing ink into the material supply system 3.

[0052] Step 4: Additive manufacturing of the particle size controllable distribution reinforcement material. Based on the workflow and process parameters of the hardware system obtained in Step 2, including the printing path, printing speed, and Z-axis downward movement thickness of the additive manufacturing forming platform 1; the number of turns of the spiral separation channel 21 in the spiral separation and assembly system 2, the rotation direction and rotation speed of the digital rotation device 25, the real-time adjustment sequence and assembly type of the digital assembly extrusion head 26; and the conveying speed of the printing ink by the material pumping device 32 in the material supply system 3, the printing ink is conveyed into the spiral separation channel 21. Based on the mechanism of manipulating particles using inertial microfluidics, enhanced particles or sacrificial template particles exhibit a certain gradient distribution near the material separation outlet 29. After being separated by the separation material separation outlet 29, they flow into different material temporary storage cylinders 23 for temporary storage. Then, through each assembly conveying hose 24, the printing ink containing particles with different particle size distributions is conveyed into the corresponding extrusion heads of the digital assembly extrusion head 26. Different permutations and combinations of the extrusion heads can achieve different particle size distribution patterns within the printing channel. Finally, the extruded printing ink is preliminarily cured using the light curing system 27;

[0053] S103, Post-processing step: Place the formed 3D printed sample in an ultraviolet curing machine for 2 - 15 hours with a power of 300 - 2000W. If the internal particles are sacrificial template particles, place the cured sample in hot water at 40 - 60°C for 5 - 24h.

[0054] The present invention has the following beneficial effects:

[0055] First, develop a high-efficiency 3D printing device and method for gradient materials based on a spiral channel, which can achieve a gradient distribution of the enhanced particle size in the composite material or the pore size of the porous material in the cross-section direction within a single printed line;

[0056] Second, the 3D printing device and method proposed by the present invention can achieve various forms of gradient distributions of the enhanced particle size in the composite material and the pore size of the porous material within a single printed line by dynamically adjusting the assembly form of the digital assembly extrusion head 26 during the printing process, including more complex gradient distributions such as small → large, large → small, small → large → small, and large → small → large;

[0057] Third, the 3D printing device and method proposed by the present invention can achieve combined printing of composite materials and porous materials and a gradient distribution of the enhanced particle size and the pore size of the porous material if it contains two or more material supply systems;

[0058] Fourth, the 3D printing device and method proposed by the present invention have the advantages of simple device, easy operation, precise operation, and low cost. Description of the Drawings

[0059] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0060] Figure 1 It is a schematic configuration diagram of an efficient 3D printing system for gradient materials based on a spiral channel proposed by the present invention.

[0061] Figure 2 It is the spiral separation channel described in an efficient 3D printing device and method for gradient materials based on a spiral channel of the present invention.

[0062] Figure 3 It is a schematic diagram of the screening and separation of different particle size particles in the matrix material in the spiral separation channel described in an efficient 3D printing device and method for gradient materials based on a spiral channel of the present invention.

[0063] Figure 4 In the present invention, by adjusting the digital assembly extrusion head, a distributive pattern with designable particle sizes of reinforcing particles in the composite material within the printing channel can be achieved;

[0064] Figure 5 In the present invention, by adjusting the digital assembly extrusion head, a distributive pattern with designable pore diameters in the porous material within the printing channel can be achieved;

[0065] The reference signs in the figure are represented as:

[0066] Additive manufacturing forming platform 1, spiral separation assembly system 2, material supply system 3, computer control system 4;

[0067] Spiral separation channel 21, separation and conveying channel 22, material temporary storage cylinder 23, assembly conveying hose 24, digital rotation device 25, digital assembly extrusion head 26, light curing system 27, material conveying inlet 28, material separation outlet 29;

[0068] Material conveying channel 31, material pumping device 32, storage tank 33, anti-settling stirring device 34.

[0069] Specific implementation cases

[0070] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0071] The present invention solves the technical problem in traditional 3D printing technology that it is impossible to achieve a complex gradient distribution of particle sizes of reinforcing particles in a composite material or pore diameters of a porous material. For specific technical solutions, please refer to Figure 1As shown in the figure, a high-efficiency 3D printing device for gradient materials based on a spiral flow channel, comprising:

[0072] An additive manufacturing forming platform 1, which is a basic component of the 3D printing device. Its built-in motion system enables the additive manufacturing forming platform 1 to move in a plane and in the vertical direction. When the reinforced particle composite material with a gradient particle size distribution is extruded by the spiral separation and assembly system 2, combined with the movement of the additive manufacturing forming platform 1, the cumulative forming of the gradient particle size reinforced material can be realized;

[0073] A spiral separation and assembly system 2, which is the core functional component of the 3D printing device of the present invention. After the printing ink is transported from the material transport inlet 28 into the spiral separation and assembly system 2, the particles with different particle sizes in the printing ink show a gradient distribution in the cross-sectional direction of the spiral separation channel 21. Then, combined with the material temporary storage cylinder 23 and the digital assembly extrusion head 26, a designed gradient mode distribution of particles with different particle sizes in the printing channel can be realized;

[0074] A material supply system 3, which is used to hold and transport the printing ink containing a rich particle size distribution, and transports the printing ink to the spiral separation and assembly system 2 at a fixed time and speed through the material transport channel 31;

[0075] A computer control system 4, which is the control center of the entire 3D printing device. According to the three-dimensional model of the particle reinforced composite material or porous material with a gradient particle size distribution, the printing process flow is decomposed, used to control the working processes of the additive manufacturing forming platform 1, the spiral separation and assembly system 2 and the material supply system 3, and the optimal process parameters are selected.

[0076] Further, the additive manufacturing forming platform 1 includes:

[0077] An additive manufacturing forming platform software system, which is integrated in the computer control system 4 and is used to control the movement of the additive manufacturing forming platform hardware system in the horizontal plane and in the vertical direction;

[0078] An additive manufacturing forming platform hardware system, which is the physical basis for the additive manufacturing forming platform 1 to realize motion programming. The movement of the additive manufacturing forming platform hardware system in three-dimensional space can realize the controllable layer-by-layer deposition and cumulative forming of the material extruded by the spiral separation and assembly system 2.

[0079] Further, the spiral separation and assembly system 2 includes:

[0080] A spiral separation channel 21( Figure 2) As the core component of the spiral separation and assembly system 2, it utilizes the mechanism of inertial microfluidics to manipulate particles. Benefiting from the unique size-dependent characteristics of secondary flow and inertial lift, it can prompt the printing ink particles to exhibit a gradient distribution according to particle size. Then, through the material separation and delivery outlet 28, the printing ink containing different particle size ranges is separated and delivered to the material temporary storage cylinder 23;

[0081] The separation and delivery channel 22, which is connected to the material separation outlet 29 of the spiral separation channel 21 at the upper end and to the material temporary storage cylinder 23 at the lower end, can deliver the separated printing ink containing different particle size ranges to the material temporary storage cylinder 23 ( Figure 3 ) for intermediate storage;

[0082] The material temporary storage cylinder 23 temporarily stores the separated printing ink containing particles within a certain particle size range through the separation and delivery channel 22;

[0083] The assembly delivery hose 24, which is connected to the material temporary storage cylinder 23 at the upper end and to the digital assembly extrusion head 26 at the lower end, further delivers the separated printing ink to the corresponding extrusion heads in the digital assembly extrusion head 26. In addition, the material of the assembly delivery hose 24 is a soft material, which can achieve a certain amount of torsional deformation, facilitating the position adjustment and reassembly of the extrusion heads in the digital assembly extrusion head 26;

[0084] The rotating device 25, which is integrated with the digital assembly extrusion head 26, can drive the digital assembly extrusion head 26 to rotate clockwise by 0 - 90° and counterclockwise by 0 - 90° during the printing process;

[0085] The digital assembly extrusion head 26 delivers the separated materials containing particles within different particle size ranges to the corresponding extrusion heads in the digital assembly extrusion head 26, and automatically assembles the extrusion heads in different arrangements according to needs, thereby achieving an adjustable and designable particle size assembly distribution of the particles in the composite material;

[0086] The photocuring system 27 is used to cure the printing ink extruded from the digital assembly extrusion head 26 in real time and in situ, and fix the particle size distribution of the particles in the printing channel;

[0087] The material delivery inlet 28 delivers the printing ink with a rich particle size distribution from the material delivery inlet 28 to the spiral separation channel 21;

[0088] The material separation outlet 29 separates the printing ink containing different particle size ranges from the material separation outlet 29 and temporarily stores it in the material temporary storage cylinder 23.

[0089] Furthermore, the material supply system 3 includes:

[0090] The material delivery channel 31 connects the material supply system 3 and the spiral separation and assembly system 2, and can deliver the printing ink with a rich particle size distribution from the material supply system 3 to the spiral separation and assembly system 2;

[0091] The material pumping device 32 is used to control the delivery time and delivery speed of the unseparated printing ink from the material supply system 3 to the spiral separation and assembly system 2;

[0092] The storage tank 33 is used to store and hold the unseparated printing ink;

[0093] The anti-settling stirring device 34 is used to prevent the settlement of particles in the printing ink in the storage tank 33 and rotate and stir at a fixed time and fixed speed.

[0094] Among them, two or more material supply systems 3 can be set as needed.

[0095] Furthermore, the computer control system 4 includes:

[0096] The additive manufacturing module is used to control the working process and moving speed of the additive manufacturing forming platform during the printing process;

[0097] The print head rotation and assembly module is used to control the arrangement, assembly and rotation movement of the print head in real time during the printing process to obtain an ideal particle size distribution;

[0098] The material delivery module is used to control the delivery time and delivery speed of the unseparated printing ink.

[0099] Additionally, a high-efficiency 3D printing method for gradient materials based on a spiral flow channel includes:

[0100] S101, Material preparation

[0101] Printing ink matrix materials: 60 - 85 wt% of polyurethane acrylate, 1 - 5 wt% of photoinitiator 1 - hydroxycyclohexyl benzophenone, 18 - 25 wt% of 1,6 - 2 diol diacrylate;

[0102] Reinforcing particles: one or a combination of several of boron nitride, aluminum nitride, silicon nitride, silicon carbide, aluminum oxide, beryllium oxide, magnesium oxide, zinc oxide, silicon oxide, graphite, starch, carbon powder, ammonium bicarbonate, polymethyl methacrylate microspheres, polystyrene microspheres;

[0103] Sacrificial template particles: The sacrificial template particles are easily removable materials, such as granular sugar particles, salt particles, iodine particles, etc., which can be removed through post - treatment processes (heating, soaking);

[0104] Among them, the reinforcing particles are used to enhance the mechanical or physical properties of the matrix material;

[0105] Among them, sacrificial template particles are used to manufacture porous materials;

[0106] Among them, the particle size distributions of the reinforcing particles and the sacrificial template particles are 2 - 200 μm;

[0107] Add 5 - 30 vol% of reinforcing particles or sacrificial template particles to the matrix material for mixing, stir evenly, and set aside;

[0108] S102, additive manufacturing of the reinforcing particle size gradient distribution material, specifically including:

[0109] Step 1: Construction and decomposition of the solid model. Select appropriate reinforcing particles or sacrificial template particles according to functional requirements, and determine the distribution pattern of the reinforcing particle size or sacrificial template particle size and the macroscopic geometric parameters of the model;

[0110] Step 2: Decomposition of the hardware system working process and programming of process parameters. Based on the distribution information of the reinforcing particle size or sacrificial template particle size and the macroscopic geometric parameters of the model determined in Step 1, determine the printing path, printing speed, and Z-axis downward movement thickness of the additive manufacturing forming platform 1; the number of turns of the spiral separation channel 21 in the spiral separation and assembly system 2, the rotation direction and rotation speed of the digital rotation device 25, the real-time adjustment sequence and assembly type of the digital assembly extrusion head 26; and the conveying speed of the printing ink of the material pumping device 32 in the material supply system 3;

[0111] Among them, the moving speed of the additive manufacturing forming platform 1 in the X - Y plane is 1 mm / s - 20 mm / s;

[0112] Among them, during the printing and forming process of the additive manufacturing forming platform 1, the thickness of the z-axis downward movement of one layer thickness is 0.1 - 0.7 mm;

[0113] Among them, the number of turns of the spiral separation channel 21 in the spiral separation and assembly system 2 is 0 - 20 turns;

[0114] Among them, the rotation speed of the digital rotation device 25 in the spiral separation and assembly system 2 is 0.1 - 2.5 rpm;

[0115] Among them, the conveying speed of the printing ink of the material pumping device 32 is 40 ml / min - 400 ml / min;

[0116] Step 3: Set the preferred working process, printing path, and printing process, and load the printing ink into the material supply system 3;

[0117] Step 4: Additive manufacturing of the particle size controllable distribution reinforcing material. Based on the working process and process parameters of the hardware system obtained in Step 2, including the printing path, printing speed, and Z-axis downward movement thickness of the additive manufacturing forming platform 1; the number of turns of the spiral separation channel 21 in the spiral separation and assembly system 2, the rotation direction and rotation speed of the digital rotation device 25, the real-time adjustment sequence and assembly type of the digital assembly extrusion head 26; and the conveying speed of the printing ink by the material pumping device 32 in the material supply system 3, the printing ink is conveyed into the spiral separation channel 21. Based on the mechanism of manipulating particles using inertial microfluidics, the enhanced particles or sacrificial template particles show a certain gradient distribution near the material separation outlet 29. After being separated by the separation material separation outlet 29, they flow into different material temporary storage cylinders 23 for temporary storage, and then the printing ink containing particles with different particle size distributions is conveyed to the corresponding extrusion heads in the digital assembly extrusion head 26 through each assembly conveying hose 24. Different permutations and combinations of the extrusion heads can achieve different particle size distribution patterns in the printing channel. Finally, the extruded printing ink is preliminarily cured using the photocuring system 27;

[0118] S103, Post-processing step: Place the formed 3D printed sample in an ultraviolet curing machine for 2 - 15 hours with a power of 300 - 2000W. If the internal particles are sacrificial template particles, place the cured sample in hot water at 40 - 60°C for 5 - 24h.

[0119] A more preferred first embodiment of the method involved in the present application is as follows:

[0120] Printing ink matrix material: 70wt% polyurethane acrylate, 5wt% photoinitiator 1-hydroxycyclohexyl phenyl ketone, 25wt% 1,6 - 2 diol diacrylate;

[0121] The reinforcing particles selected are alumina; their particle sizes are 5, 50, 80, 110, 140, 180μm respectively

[0122] Add 5vol% of the reinforcing particles or sacrificial template particles to the matrix material for mixing, stir evenly, and set aside;

[0123] Construction and decomposition of the three-dimensional model: Determine the particle size distribution pattern of the reinforcing particles and the macroscopic geometric parameters of the model according to the functional requirements;

[0124] Decomposition of the hardware system working process and programming of the process parameters, based on the distribution information of the particle sizes of the reinforcing particles ( Figure 4) and the macroscopic geometric parameters of the model, determine the printing path, printing speed of 10 mm / s, and Z-axis downward movement thickness of 0.3 mm of the additive manufacturing forming platform 1; the number of turns of the spiral separation channel 21 in the spiral separation and assembly system 2 is 5 turns, the rotation direction and rotation speed of the digital rotation device 25 are 1 rpm, the real-time adjustment sequence and assembly type of the digital assembly extrusion head 26; and the conveying speed of the printing ink of the material pumping device 32 in the material supply system 3 is 100 ml / min;

[0125] Set the preferred working process, printing path and printing process, and load the printing ink into the material supply system 3;

[0126] For the additive manufacturing of particle size controllable distribution reinforced materials, based on obtaining the working process and process parameters of the hardware system, including the printing path, printing speed and Z-axis downward movement thickness of the additive manufacturing forming platform 1; the number of turns of the spiral separation channel 21, the rotation direction and rotation speed of the digital rotation device 25, the real-time adjustment sequence and assembly type of the digital assembly extrusion head 26 in the spiral separation and assembly system 2; and the conveying speed of the printing ink of the material pumping device 32 in the material supply system 3, convey the printing ink into the spiral separation channel 21, based on the mechanism of using inertial microfluidics to manipulate particles, enhance the appearance of a certain gradient distribution of particles or sacrificial template particles near the material separation outlet 29, and after being separated by the separation material separation outlet 29, flow into different material temporary storage cylinders 23 for temporary storage, and then through each assembly conveying hose 24, convey the printing ink containing particles with different particle size distributions into the corresponding extrusion heads of the digital assembly extrusion head 26. Different permutations and combinations of each extrusion head can achieve different particle size distribution patterns in the printing channel. Finally, use the photocuring system 27 to preliminarily cure the extruded printing ink;

[0127] S103, post-processing step, place the formed 3D printed sample in an ultraviolet curing machine for 10 hours, with a power of 300W. If the internal particles are sacrificial template particles, place the cured sample in hot water at 40 - 60 °C for 5 - 24 h.

[0128] A more preferred second embodiment of the method involved in the present application is as follows:

[0129] Printing ink matrix material: 78 wt% polyurethane acrylate, 2 wt% photoinitiator 1-hydroxycyclohexyl benzophenone, 20 wt% 1,6-2 diol diacrylate;

[0130] The sacrificial template particles are selected as salt particles with particle sizes of 10, 20, 30, 40, 50, and 60 μm respectively;

[0131] Add 15 vol% of the reinforcing particles or sacrificial template particles to the matrix material for mixing, stir evenly, and set aside;

[0132] Construction and decomposition of the solid model, determining the particle size distribution pattern of the sacrificial template particles and the macroscopic geometric parameters of the model according to the functional requirements;

[0133] Decomposition of the hardware system working process and programming of process parameters, based on the distribution information of the particle size of the sacrificial template particles ( Figure 5 ) and the macroscopic geometric parameters of the model, determining the printing path, printing speed of 8 mm / s and Z-axis downward movement thickness of 0.5 mm of the additive manufacturing forming platform 1; the number of turns of the spiral separation channel 21 in the spiral separation and assembly system 2, the rotation direction and rotation speed of 2 rpm of the digital rotation device 25, the real-time adjustment sequence and assembly type of the digital assembly extrusion head 26; and the conveying speed of the printing ink of the material pumping device 32 in the material supply system 3 is 200 ml / min;

[0134] Set the preferred working process, printing path and printing process, and load the printing ink into the material supply system 3;

[0135] Additive manufacturing of the particle size controllable distribution reinforcing material, based on obtaining the working process and process parameters of the hardware system, including the printing path, printing speed and Z-axis downward movement thickness of the additive manufacturing forming platform 1; the number of turns of the spiral separation channel 21 in the spiral separation and assembly system 2, the rotation direction and rotation speed of the digital rotation device 25, the real-time adjustment sequence and assembly type of the digital assembly extrusion head 26; and the conveying speed of the printing ink of the material pumping device 32 in the material supply system 3, conveying the printing ink to the spiral separation channel 21, based on the mechanism of manipulating particles by inertial microfluidics, enhancing a certain gradient distribution of the particles or sacrificial template particles near the material separation outlet 29, flowing into different material temporary storage cylinders 23 for temporary storage after being separated by the separation material separation outlet 29, and then conveying the printing ink containing particles with different particle size distributions to the corresponding extrusion heads in the digital assembly extrusion head 26 through each assembly conveying hose 24. Different permutations and combinations of the extrusion heads can realize different particle size distribution patterns in the printing channel. Finally, the extruded printing ink is preliminarily cured by the photocuring system 27;

[0136] S103, post-processing step, placing the formed 3D printed sample in an ultraviolet curing machine for 3 hours with a power of 800 W. If the internal particles are sacrificial template particles, place the cured sample in hot water at 60 °C for 12 h.

Claims

1. An efficient 3D printing device for gradient materials based on a spiral flow channel, characterized in that, Including: An additive manufacturing forming platform (1), which is a basic component of a 3D printing device. Its built-in motion system enables the additive manufacturing forming platform (1) to move in a plane and in the vertical direction. When the reinforced particle composite material with a gradient particle size distribution is extruded by the spiral separation and assembly system (2), combined with the movement of the additive manufacturing forming platform (1), the cumulative forming of the gradient particle size reinforced material can be realized; A spiral separation and assembly system (2), which is the core functional component of the 3D printing device of the present invention. After the printing ink is transported from the material inlet (28) into the spiral separation and assembly system (2), the particles with different particle sizes in the printing ink show a gradient distribution in the cross-sectional direction of the spiral separation channel (21). Combined with the material temporary storage cylinder (23) and the digital assembly extrusion head (26), it can realize the designed gradient mode distribution of particles with different particle sizes in the printing channel; A material supply system (3), which is used to hold and transport the printing ink with a rich particle size distribution, and transports the printing ink to the spiral separation and assembly system (2) regularly and at a constant speed through the material transport channel (31); A computer control system (4), which is the control center of the entire 3D printing device. According to the three-dimensional model of the particle-reinforced composite material or porous material with a gradient particle size distribution, the printing process flow is decomposed to control the working processes of the additive manufacturing forming platform (1), the spiral separation and assembly system (2) and the material supply system (3), and the optimal process parameters are selected.

2. The high-efficiency 3D printing device for gradient materials based on a spiral flow channel according to claim 1, wherein, The additive manufacturing forming platform (1) includes: An additive manufacturing forming platform software system, which is integrated in the computer control system (4) to control the movement of the additive manufacturing forming platform hardware system in the horizontal plane and in the vertical direction; An additive manufacturing forming platform hardware system, which is the physical basis for the additive manufacturing forming platform (1) to realize motion programming. The movement of the additive manufacturing forming platform hardware system in three-dimensional space can realize the controllable layer-by-layer deposition and cumulative forming of the material extruded by the spiral separation and assembly system (2).

3. The high-efficiency 3D printing device for gradient materials based on a spiral flow channel according to claim 1, characterized in that, The spiral separation and assembly system (2) includes: A spiral separation channel (21), which is the core component of the spiral separation and assembly system (2). Using the mechanism of inertial microfluidics to manipulate particles and benefiting from the unique size-dependent characteristics of secondary flow and inertial lift, it can promote the particles in the printing ink to show a gradient distribution according to the particle size. Then, through the material separation and transport outlet (28), the printing ink containing different particle size ranges is separated and transported to the material temporary storage cylinder (23); A separation and transport channel (22), which is connected to the material separation outlet (29) of the spiral separation channel (21) at the upper end and to the material temporary storage cylinder (23) at the lower end, and can transport the separated printing ink containing different particle size ranges to the material temporary storage cylinder (23) for transfer and storage; A material temporary storage cylinder (23), which temporarily holds the separated printing ink containing particles within a certain particle size range through the separation and transport channel (22); An assembled conveying hose (24) is connected to a material temporary storage cylinder (23) at the upper part and a digital assembled extrusion head (26) at the lower part, further conveying the separated printing ink to the corresponding extrusion heads in the digital assembled extrusion head (26). Additionally, the assembled conveying hose (24) is made of a soft material, enabling a certain degree of torsional deformation, which facilitates the position adjustment and reassembly of the extrusion heads in the digital assembled extrusion head (26); A rotating device (25) is integrated with the digital assembled extrusion head (26), which can drive the digital assembled extrusion head (26) to rotate clockwise by 0 - 90° and counterclockwise by 0 - 90° during the printing process; The digital assembled extrusion head (26) conveys the materials containing particles in different particle size ranges after separation to the corresponding extrusion heads in the digital assembled extrusion head (26), and automatically assembles the extrusion heads in different arrangements according to needs, thereby realizing an adjustable and designable particle size assembly distribution of particles in the composite material; A photocuring system (27) is used to cure the printing ink extruded from the digital assembled extrusion head (26) in real time and in situ, fixing the particle size distribution of the particles in the printing channel; A material conveying inlet (28) conveys the printing ink with a rich particle size distribution from the material conveying inlet (28) to the spiral separation channel (21); A material separation outlet (29) separates the printing ink containing different particle size ranges from the material separation outlet (29) and temporarily stores it in the material temporary storage cylinder (23).

4. The high-efficiency 3D printing device for gradient materials based on a spiral flow channel according to claim 1, characterized in that, The material supply system (3) includes: A material conveying channel (31) connects the material supply system (3) and the spiral separation and assembly system (2), and can convey the printing ink with a rich particle size distribution from the material supply system (3) to the spiral separation and assembly system (2); A material pumping device (32) is used to control the conveying time and conveying speed of the unseparated printing ink from the material supply system (3) to the spiral separation and assembly system (2); A storage tank (33) is used to store and hold the unseparated printing ink; An anti - sedimentation stirring device (34) is used to prevent the sedimentation of particles in the printing ink in the storage tank (33), and rotates and stirs at a fixed time and speed.

5. The high-efficiency 3D printing device for gradient materials based on a spiral flow channel according to claim 1, characterized in that, The material supply system (3) can be set to two or more according to needs.

6. The high-efficiency 3D printing device for gradient materials based on a spiral flow channel according to claim 1, wherein, The computer control system (4) includes: An additive manufacturing module is used to control the working process and moving speed of the additive manufacturing forming platform during the printing process; A printing head rotation and assembly module is used to control the arrangement, assembly and rotation movement of the printing head in real time during the printing process to obtain an ideal particle size distribution; A material conveying module is used to control the conveying time and conveying speed of the unseparated printing ink.

7. A method for efficient 3D printing of gradient materials based on a spiral flow channel using the apparatus for efficient 3D printing of gradient materials based on a spiral flow channel according to any one of claims 1 to 6, characterized in that, It includes: S101, Material preparation Printing ink matrix materials: 60 - 85 wt% of polyurethane acrylate, 1 - 5 wt% of photoinitiator 1 - hydroxycyclohexyl phenyl ketone, 18 - 25 wt% of 1,6 - diol diacrylate; Reinforcing particles: one or a combination of boron nitride, aluminum nitride, silicon nitride, silicon carbide, aluminum oxide, beryllium oxide, magnesium oxide, zinc oxide, silicon oxide, graphite, starch, carbon powder, ammonium bicarbonate, polymethyl methacrylate microspheres, polystyrene microspheres; Sacrificial template particles: The sacrificial template particles are made of a material that can be easily removed and can be removed through post-treatment processes (heating, soaking); Among them, the reinforcing particles are used to enhance the mechanical or physical properties of the matrix material; Among them, the sacrificial template particles are used to manufacture porous materials; Among them, the particle size distribution of the reinforcing particles and the sacrificial template particles is 2 - 200 μm; Add 5 - 30 vol% of the reinforcing particles or the sacrificial template particles to the matrix material for mixing, stir evenly, and set aside; S102, additive manufacturing of a material with a gradient particle size distribution of reinforcing particles, specifically including: Step 1: Construction and decomposition of a three-dimensional model. Select appropriate reinforcing particles or sacrificial template particles according to functional requirements, and determine the distribution pattern of the particle size of the reinforcing particles or the particle size of the sacrificial template particles and the macroscopic geometric parameters of the model; Step 2: Decomposition of the working process of the hardware system and programming of process parameters. Based on the distribution information of the particle size of the reinforcing particles or the particle size of the sacrificial template particles and the macroscopic geometric parameters of the model determined in Step 1, determine the printing path, printing speed, and the thickness of the Z-axis downward movement of the additive manufacturing forming platform (1); the number of turns of the spiral separation channel (21) in the spiral separation and assembly system (2), the rotation direction and rotation speed of the digital rotation device (25), the real-time adjustment sequence and assembly type of the digital assembly extrusion head (26); and the conveying speed of the printing ink of the material pumping device (32) in the material supply system (3); Among them, the moving speed of the additive manufacturing forming platform (1) in the X-Y plane is 1 mm / s to 20 mm / s; Among them, the thickness of the Z-axis downward movement of the additive manufacturing forming platform (1) during printing and forming is 0.1 - 0.7 mm; Among them, the number of turns of the spiral separation channel (21) in the spiral separation and assembly system (2) is 0 - 20 turns; Among them, the rotation speed of the digital rotation device (25) in the spiral separation and assembly system (2) is 0.1 - 2.5 rpm; Among them, the conveying speed of the printing ink of the material pumping device (32) is 40 ml / min - 400 ml / min; Step 3: Set the preferred working process, printing path, and printing process, and load the printing ink into the material supply system (3); Step 4: Additive manufacturing of the particle size controllable distribution reinforcing material. Based on the workflow and process parameters of the hardware system obtained in Step 2, including the printing path, printing speed, and Z-axis downward movement thickness of the additive manufacturing forming platform (1); the number of turns of the spiral separation channel (21) in the spiral separation and assembly system (2), the rotation direction and rotation speed of the digital rotation device (25), the real-time adjustment sequence and assembly type of the digital assembly extrusion head (26); and the conveying speed of the printing ink by the material pumping device (32) in the material supply system (3), the printing ink is conveyed into the spiral separation channel (21). Based on the mechanism of manipulating particles using inertial microfluidics, a certain gradient distribution of the reinforcing particles or sacrificial template particles appears near the material separation outlet (29). After being separated by the separation material separation outlet (29), they flow into different material temporary storage cylinders (23) for temporary storage. Then, through each assembly conveying hose (24), the printing ink containing particles with different particle size distributions is conveyed into the corresponding extrusion heads in the digital assembly extrusion head (26). Different permutations and combinations of the extrusion heads can achieve different particle size distribution patterns in the printing channel. Finally, the extruded printing ink is preliminarily cured using the photocuring system (27). S103, Post-processing step: Place the formed 3D printed sample in an ultraviolet curing machine for 2 - 15 hours with a power of 300 - 2000W. If the internal particles are sacrificial template particles, place the cured sample in hot water at 40 - 60°C for 5 - 24h.

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