A single-nozzle multi-channel feeding extrusion device and method based on laminar flow mixing

Abstract

This application relates to the fields of multi-material photopolymerization 3D printing and functionally graded ceramic materials, and particularly to a single-nozzle multi-channel feeding extrusion device and method based on laminar flow mixing. This method can achieve mesoscopic continuous composition gradient spreading of heterogeneous ceramic slurries. The extrusion device includes a gradient generation unit and a mixing enhancement unit. The gradient generation unit uses a rectangular channel geometric segmentation method combined with a baffle structure to form a mesoscopic continuous composition gradient distribution in the X-axis direction. The mixing enhancement unit introduces a Coriolis force field through a grinding roller to reconstruct the Y-Z plane vector field to improve the Y-axis mixing efficiency, so that the extruded filaments have both a continuous composition gradient in the X-axis and homogeneous mixing in the Y-axis. The nozzle supports single-nozzle or multi-nozzle collaborative operation, and the gradient bandwidth and spreading accuracy can be dynamically adjusted by adjusting the nozzle attitude and spreading speed.

Description

Technical Field

[0001] This application relates to the fields of multi-material photopolymerization 3D printing and functionally graded ceramic materials technology, and in particular to a single-nozzle multi-channel feeding extrusion device and method based on laminar flow mixing, which can realize mesoscopic continuous composition gradient spreading of heterogeneous ceramic slurry. Background Technology

[0002] Functionally graded ceramic materials (FJCs) exhibit broad application prospects in aerospace, biomedicine, and energy fields because they can continuously or discretely vary their composition, structure, and properties in space to meet the personalized performance requirements of materials under extreme service environments. However, traditional preparation methods such as powder metallurgy and chemical vapor deposition are often complex, costly, and difficult to achieve precise and continuous control of composition in complex structures.

[0003] Multi-material 3D printing technology, with its significant advantages of high precision, flexibility, and integrated forming, demonstrates unique technological advantages in the preparation of functionally graded ceramics by precisely controlling the distribution and combination of materials between or within layers. Currently, the main mechanisms suitable for multi-material 3D printing include material extrusion, photopolymerization, and energy deposition: material extrusion, while having lower costs, has limited forming accuracy; energy deposition is suitable for high-performance metallic materials, but the equipment is complex and costly; photopolymerization, with its micron-level resolution, has become the preferred solution for integrated multi-material preparation. Among them, stereolithography (SL) achieves dynamic control of local light intensity and exposure time through a point-scan exposure mode, providing a key process window for the coordinated release of stress in the gradient transition zone.

[0004] The core challenge of multi-material photopolymerization 3D printing lies in achieving precise control of material distribution through optimized feeding and placement methods. Current photopolymerization-based ceramic slurry placement technology primarily relies on two modes: silo self-leveling / scraper leveling and nozzle extrusion placement. Their integrated application allows for on-demand material placement. However, current photopolymerization-based ceramic multi-material 3D printing placement systems still face technical challenges in gradient material preparation. First, traditional silo-type placement systems suffer from two major bottlenecks: firstly, they exhibit significant limitations in controlling intralayer slurry distribution, making it difficult to achieve precise shaping of complex gradient structures; secondly, they are only suitable for constructing discrete component gradient materials, making it difficult to achieve continuous component gradient preparation. Secondly, while the single-nozzle multi-channel placement system (based on active / passive homogeneous mixing principles) developed in recent years has made breakthroughs in continuous component gradient construction, it still requires the combined placement of extruded filaments to achieve intralayer component gradient transitions, resulting in transition zone sizes limited to macroscopic scales (>1 mm).

[0005] The information disclosed in this background section is only intended to enhance the understanding of the background technology of this application, and therefore may include prior art that is not known to those skilled in the art. Summary of the Invention

[0006] This application aims to provide a single-nozzle multi-channel feeding extrusion device and method based on laminar flow mixing. The feeding extrusion device can realize the mesoscopic continuous component gradient layup of heterogeneous slurry, and the extrusion device can be used as a 3D printing nozzle.

[0007] In some embodiments of this application, a single-nozzle multi-channel feeding extrusion device based on laminar flow mixing is provided, comprising: The outer shell has a cavity formed inside, which is divided into a feeding chamber, a mixing chamber, and a discharge port from top to bottom. Two opposite sides of the outer shell are respectively provided with a first feeding port and a second feeding port, both communicating with the feeding chamber. The first feeding port is connected to a first raw material supply system for supplying a first slurry to the feeding chamber. The second feeding port is connected to a second raw material supply system for supplying a second slurry to the feeding chamber. The mixing chamber is connected to the feeding chamber and is used for mixing the two different slurries. The discharge port is configured for extruding the mixed slurry system. The gradient generation unit consists of a feeding chamber and a separation partition between the feeding chambers. The horizontal cross-section of the feeding chamber is a rectangular cross-section. The two ends of the separation partition are located in the diagonal region of the rectangular cross-section flow channel of the feeding chamber. The separation partition extends in the feeding chamber along the length of the outer shell body. The mixing enhancement unit consists of a mixing chamber and a laminar flow mixing assembly; the laminar flow mixing assembly includes a grinding roller and a roller extending through the axis of the grinding roller and along its axial direction; the grinding roller is located inside the mixing chamber, and the two ends of the roller are mounted on the outer shell body; the grinding roller does not contact the mixing chamber, so that the slurry flows to the discharge port through the gap between the grinding roller and the wall of the mixing chamber; the number of grinding rollers is at least two, and the grinding rollers are configured to mix different slurries; The power unit includes a fixed cavity, a transmission device, and a dual-axis servo motor. The fixed cavity is located on the outer side of the main body of the housing and is configured to store and fix the dual-axis servo motor. The transmission device includes pulleys and a synchronous belt. The pulleys are fixed to the shaft ends of the output shaft of the dual-axis servo motor and the rollers on which the grinding rollers are assembled. The number of pulleys is at least six. The synchronous belt cooperates with the pulleys. When the dual-axis servo motor starts to rotate, the pulleys transmit power to the rollers of the grinding rollers, driving the grinding rollers to rotate.

[0008] In some embodiments of this application, the separation partition has a variety of shapes, including straight, sine, and cosine plate shapes, so that the two different slurries exhibit different composition gradient types after mixing.

[0009] In some embodiments of this application, the outer shell body is mounted on a robotic arm so that the entire outer shell moves along a preset trajectory.

[0010] In some embodiments of this application, the separation partition extends along the length of the outer shell body within the feeding chamber, extending to the boundary between the feeding chamber and the mixing chamber.

[0011] In some embodiments of this application, both the first slurry and the second slurry are ceramic slurries.

[0012] In some embodiments of this application, the roller is supported on a bearing end cap by a bearing, and the bearing end cap is assembled on the wall of the mixing chamber.

[0013] In some embodiments of this application, the grinding roller is completely placed inside the mixing chamber, with a gap between the grinding roller and the mixing chamber, and at least two grinding rollers are of the same size with a gap between them.

[0014] In some embodiments of this application, the grinding roller is mounted on a roller shaft, which is mounted on a housing via bearings, and at least two grinding rollers rotate in the same direction and at the same speed.

[0015] In some embodiments of this application, the discharge port is connected to the mixing chamber, and the cross-section of the discharge port is rectangular, the size of which is determined according to the diameter of the extruded slurry filaments and the printing accuracy requirements.

[0016] In some embodiments of this application, the pulleys are connected to the output shaft of the dual-axis servo motor and the roller of the grinding roller, so that the grinding roller rotates synchronously when the micro dual-axis servo motor rotates. There are a total of 2 synchronous belts, and the synchronous belts cooperate with the pulleys symmetrically distributed on both sides of the outer shell.

[0017] In some embodiments of this application, the tilt angle of the outer shell body is adjusted by a position adjustment device, so that the tilt angle of the discharge port varies between 0° and 90°. Different tilt angles correspond to different discharge widths, thereby realizing diversified laying of the mixed ceramic slurry system.

[0018] In some embodiments of this application, the installation angle of the separation baffle can be changed, different shapes of separation baffles can be selected, or the two ends of the separation baffle can be fixed at different positions on both sides of the mixing chamber to change the continuous component gradient form of different slurry systems and achieve different spreading effects.

[0019] In some embodiments of this application, the dual-axis servo motor is a miniature dual-axis servo motor.

[0020] A single-nozzle multi-channel extrusion method based on laminar flow mixing employs the extrusion device described in any of the above embodiments. Both the first slurry and the second slurry are ceramic slurries. A first raw material supply system transports the first slurry into the feed chamber through a first inlet, and a second raw material supply system transports the second slurry into the feed chamber through a second inlet. The first and second slurries are separated by a separator to prevent premixing before entering the mixing zone. After flowing through the end of the separator, the first and second slurries come into contact with each other and enter the mixing enhancement unit. A dual-axis servo motor drives at least two grinding rollers to rotate in the same direction at the same speed via pulleys and a synchronous belt; the first and second slurries first flow through the area where the grinding rollers and the mixing chamber are connected and initially mixed; then they enter the gap between the grinding rollers and the inner wall of the mixing chamber and are mixed under the continuous rotation of the grinding rollers; after mixing, the slurry with a gradient distribution is extruded through the discharge port.

[0021] Compared with the prior art, the technical solution of this application has at least the following beneficial effects: When the raw material supply system supplies ceramic slurries of different components through the feed chambers on both sides, the separation baffle in the middle effectively prevents the two slurries from premixing before entering the mixing zone. After flowing past the end of the separation baffle, the two slurries come into contact with each other and enter the mixing enhancement unit. A dual-axis servo motor drives two grinding rollers to rotate in the same direction at the same speed via a synchronous belt pulley transmission system. The slurry first flows through the area connecting the grinding rollers and the mixing chamber, achieving initial mixing; then it enters the gap between the grinding rollers and the inner wall of the mixing chamber, where it is fully mixed under the continuous rotation of the grinding rollers. A certain gap is provided between the two grinding rollers to reduce the slurry flow rate in this area, thereby reducing the pressure on the sidewall of the mixing chamber and improving the operational stability of the equipment. After mixing, the slurry is extruded through the discharge port.

[0022] By altering the geometry of the separator, the mixing pattern of the two slurries can be adjusted. Simultaneously, by appropriately controlling the rotational speed of the dual-axis servo motor, a mixing effect matching the heterogeneous slurry system can be achieved. Furthermore, by adjusting the slurry extrusion speed and nozzle forward posture, the layup width of the extruded filaments can be precisely controlled, thereby regulating the size of the material transition zone and achieving a continuous gradient distribution of components at the mesoscale. This helps to improve the bonding strength of the heterogeneous material transition zone in functionally graded ceramic forming parts.

[0023] Other beneficial effects of this application will be described in detail in the following specific embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a single-nozzle multi-channel feeding extrusion device based on laminar flow mixing in some embodiments of this application; Figure 2This is a schematic diagram of the laminar flow hybrid component structure in some embodiments of this application; Figure 3 This is a top view of a single-nozzle multi-channel feeding extrusion device based on laminar flow mixing in some embodiments of this application; Figure 4 This is a schematic diagram of the overall assembly of the transmission device in some embodiments of this application.

[0025] Figures 5-8 This is a schematic diagram of separation partitions of different shapes in different embodiments of this application.

[0026] Figure 9 This is a schematic diagram of some embodiments of the extrusion effect of this application.

[0027] in: 1. Outer shell; 1a. Feeding chamber; 1b. Mixing chamber; 1c. Discharge port; 2. Gradient generation unit; 2a. Separation partition; 3. Mixing enhancement unit; 3a. Grinding roller; 3b. Roller shaft; 3c. Bearing end cover; 4. Power unit; 4a. Fixed chamber; 4b. Pulley; 4c. Synchronous belt; 4d. Miniature dual-axis servo motor. Detailed Implementation

[0028] To make the technical problem to be solved by this application, the implementation scheme, and the advantages clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. The described embodiments are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0029] Mesoscopic continuity is a continuous dynamical paradigm based on statistical mechanics, with single-particle distribution functions as the core field quantities. It introduces nonlocal interaction potentials to drive self-organized phase separation in multi-component systems through closed evolution at the mesoscopic scale using Boltzmann-BGK-like equations. This analytically transforms sharp interfaces in the traditional macroscopic sense into physically thin layers with finite characteristic widths and continuous component transitions, thus bridging molecular fluctuations and macroscopic transport with a unified evolution equation without the need for explicit interface tracking. This framework lays the constitutive foundation for describing the continuous mixing behavior of multi-component systems—i.e., mesoscopic continuous mixing—allowing the evolution of component gradients, interface distribution, and diffusion mixing during the mixing process to be self-consistently expressed within the same mesoscopic dynamical system.

[0030] Mesoscopic continuity is a material design concept that actively constructs statistically smooth gradient changes in components or microstructures at the mesoscopic scale (hundreds of nanometers to millimeters) through digital manufacturing processes. It replaces the sharp, abrupt interfaces between traditional heterogeneous materials with continuously varying transition regions, fundamentally alleviating stress concentration and achieving seamless integration of contradictory properties. This is a designable intermediate state of materials derived from biomimetic strategies and achieved through precise point-by-point energy / matter control; it serves as a crucial bridge connecting microscopic component control with the superior performance of macroscopic components.

[0031] Mesoscopic continuity is a cross-scale structural characteristic defined by the integration of my country's current national standards for additive manufacturing and materials science. It refers to the functional, continuous, and gradual change of a material's composition, microstructure, or physical properties along one or more spatial dimensions at the mesoscopic scale of 1 nanometer to 100 micrometers, without discrete interfaces or abrupt changes. Simply put, it breaks the traditional layered splicing mode of composite materials, which involves "hard materials splicing soft materials, ceramics splicing metals." Instead of leaving clear and easily broken seams between two materials, it creates a "middle zone" that smoothly transitions from material A to material B. Macroscopically, one can see a uniform and gradual change in properties such as hardness, color, and conductivity, while microscopically there are no obvious layer boundaries. This fundamentally solves the industry problem of stress concentration and easy cracking and detachment at the joints of heterogeneous materials.

[0032] Specifically, please refer to Figure 1 A single-nozzle multi-channel feeding extrusion device based on laminar flow mixing includes a housing body 1, a gradient generation unit 2, a mixing enhancement unit 3, and a power unit 4.

[0033] Please see Figure 1 , Figure 3 The outer shell 1 is made of a high-strength and high-hardness material, such as an alloy or ceramic material. The outer shell 1 can be connected to a raw material supply system via a feeding chamber 1a. The outer shell 1 is mounted on a robotic arm so that the entire outer shell 1 moves along a preset trajectory. The outer shell 1 has an interconnected feeding chamber 1a and a mixing chamber 1b. The feeding chamber 1a is used for temporarily storing or supplying ceramic slurry. The mixing chamber 1b has a rectangular cross-section and is configured as the primary location for mixing two different ceramic slurries. For example, alumina and zirconium oxide ceramic slurries enter the mixing chamber 1b through the feeding chambers 1a on both sides.

[0034] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 The laminar flow mixing assembly 3 includes a grinding roller 3a and a roller shaft 3b. The roller shaft 3b is supported on a bearing end cap 3c by bearings. The bearing end cap is assembled on the wall of the mixing chamber. A pulley 4b is mounted on the end of the shaft. The pulleys 4b are connected to each other by a synchronous belt 4c.

[0035] Please see Figure 4 The power unit 4 includes a fixed cavity 4a, a pulley 4b, a synchronous belt 4c, and a miniature dual-axis servo motor 4d. The fixed cavity 4a is fixed to the front side of the outer casing 1 and is used to mount and position the miniature dual-axis servo motor 4d. During operation, the miniature dual-axis servo motor 4d starts at a set speed. The pulley on its output shaft drives the driven pulley mounted on the roller shaft 3b via the synchronous belt 4c, thereby driving the grinding roller 3a to rotate. During rotation, the grinding roller 3a applies a shearing action to the ceramic slurry entering the mixing chamber 1b, achieving laminar flow mixing. By adjusting the speed of the miniature dual-axis servo motor 4d, the mixing requirements of different ceramic slurry systems can be adapted, ensuring the controllability and consistency of the mixing effect.

[0036] In some embodiments of this application, please refer to Figure 1 , Figure 5-8 The separation partition 2a is constructed with a variety of geometries, including but not limited to linear, sinusoidal and cosine types, to meet the mixing requirements of different ceramic slurry systems.

[0037] In some embodiments of this application, the depth of the separation partition 2a is set to be greater than the installation height of the lowest edge of the feed chamber 1a relative to the outer shell body 1, so as to ensure that ceramic slurries of different components remain effectively isolated before entering the mixing chamber 1b, avoiding premature mixing. In addition, the separation partition 2a is also configured to adjust the entry ratio of different ceramic slurry systems by means of its shape and position, thereby achieving precise control of the component ratio of the mixing system.

[0038] The extrusion apparatus described in this application includes a gradient generation unit and a mixing enhancement unit. The gradient generation unit employs a rectangular flow channel geometric segmentation method combined with a baffle structure to form a mesoscopic continuous component gradient distribution in the X-axis direction. The mixing enhancement unit introduces a Coriolis force field through a grinding roller to reconstruct the YZ plane vector field, thereby improving the Y-axis mixing efficiency and enabling the extruded filaments to possess both a continuous component gradient in the X-axis and homogeneous mixing in the Y-axis. The nozzle supports single-nozzle or multi-nozzle collaborative operation, and the gradient bandwidth and spreading accuracy can be dynamically adjusted by regulating the nozzle attitude and spreading speed.

[0039] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.

Claims

1. A single-nozzle multi-channel feeding extrusion device based on laminar flow mixing, characterized in that, include: The outer shell has a cavity formed inside, which is divided into a feeding chamber, a mixing chamber, and a discharge port from top to bottom. Two opposite sides of the outer shell are respectively provided with a first feeding port and a second feeding port, both communicating with the feeding chamber. The first feeding port is connected to a first raw material supply system for supplying a first slurry to the feeding chamber. The second feeding port is connected to a second raw material supply system for supplying a second slurry to the feeding chamber. The mixing chamber is connected to the feeding chamber and is used for mixing the two different slurries. The discharge port is configured for extruding the mixed slurry system. The gradient generation unit consists of a feeding chamber and a separation partition between the feeding chambers. The horizontal cross-section of the feeding chamber is a rectangular cross-section. The two ends of the separation partition are located in the diagonal region of the rectangular cross-section flow channel of the feeding chamber. The separation partition extends in the feeding chamber along the length of the outer shell body. The mixing enhancement unit consists of a mixing chamber and a laminar flow mixing assembly; the laminar flow mixing assembly includes a grinding roller and a roller extending through the axis of the grinding roller and along its axial direction; the grinding roller is located inside the mixing chamber, and the two ends of the roller are mounted on the outer shell body; the grinding roller does not contact the mixing chamber, so that the slurry flows to the discharge port through the gap between the grinding roller and the wall of the mixing chamber; the number of grinding rollers is at least two, and the grinding rollers are configured to mix different slurries; The power unit includes a fixed cavity, a transmission device, and a dual-axis servo motor. The fixed cavity is located on the outer side of the main body of the housing and is configured to store and fix the dual-axis servo motor. The transmission device includes pulleys and a synchronous belt. The pulleys are fixed to the shaft ends of the output shaft of the dual-axis servo motor and the rollers on which the grinding rollers are assembled. The number of pulleys is at least six. The synchronous belt cooperates with the pulleys. When the dual-axis servo motor starts to rotate, the pulleys transmit power to the rollers of the grinding rollers, driving the grinding rollers to rotate.

2. The single-nozzle multi-channel feeding extrusion device based on laminar flow mixing according to claim 1, characterized in that, The separation plate has various shapes, including straight, sine, and cosine plate shapes, so that the two different slurries can present different composition gradient types after mixing.

3. The single-nozzle multi-channel feeding extrusion device based on laminar flow mixing according to claim 1, characterized in that, The outer shell is mounted on a robotic arm so that the entire shell moves along a preset trajectory.

4. The single-nozzle multi-channel feeding extrusion device based on laminar flow mixing according to claim 1, characterized in that, The separation partition extends along the length of the outer shell body within the feeding chamber, reaching the boundary between the feeding chamber and the mixing chamber; both the first slurry and the second slurry are ceramic slurries.

5. The single-nozzle multi-channel feeding extrusion device based on laminar flow mixing according to claim 1, characterized in that, The roller is supported on the bearing end cover by bearings, and the bearing end cover is assembled on the wall of the mixing chamber; the grinding roller is completely placed in the mixing chamber, and there is a gap between the grinding roller and the mixing chamber. At least two grinding rollers are the same size, and there is a gap between the two grinding rollers.

6. The single-nozzle multi-channel feeding extrusion device based on laminar flow mixing according to claim 1, characterized in that, The grinding rollers are mounted on a shaft, which is mounted on a housing via bearings. At least two grinding rollers rotate in the same direction and at the same speed.

7. The single-nozzle multi-channel feeding extrusion device based on laminar flow mixing according to claim 1, characterized in that, The discharge port is connected to the mixing chamber, and the cross-section of the discharge port is rectangular. The size is determined according to the diameter of the extruded slurry filaments and the printing accuracy requirements. The pulleys are connected to the output shaft of the dual-axis servo motor and the roller of the grinding roller, respectively, so that the grinding roller rotates synchronously when the micro dual-axis servo motor rotates. There are a total of 2 synchronous belts, which cooperate with the pulleys symmetrically distributed on both sides of the outer shell.

8. The single-nozzle multi-channel feeding extrusion device based on laminar flow mixing according to claim 1, characterized in that, The tilt angle of the outer shell body is adjusted by the position adjustment device, so that the tilt angle of the discharge port can vary between 0° and 90°, and different tilt angles correspond to different discharge widths. The installation angle of the separation baffle can be changed, different shapes of separation baffles can be selected, or the two ends of the separation baffle can be fixed at different positions on both sides of the mixing chamber to change the continuous component gradient form of different slurry systems.

9. A single-nozzle multi-channel feeding extrusion device based on laminar flow mixing according to claim 1, characterized in that, The dual-axis servo motor is a miniature dual-axis servo motor.

10. A single-nozzle multi-channel feeding extrusion method based on laminar flow mixing, characterized in that, It employs the extrusion apparatus according to any one of claims 1-9, wherein the first slurry and the second slurry are both ceramic slurries, the first raw material supply system transports the first slurry into the feed chamber through the first feed port, the second raw material supply system transports the second slurry into the feed chamber through the second feed port, and the first slurry and the second slurry are separated by a separation partition to prevent the first slurry and the second slurry from being premixed before entering the mixing zone; After flowing through the end of the separation baffle, the first and second slurries come into contact with each other and enter the mixing and strengthening unit. A dual-axis servo motor drives at least two grinding rollers to rotate in the same direction and at the same speed via pulleys and a synchronous belt; The first and second slurries first flow through the area where the grinding roller connects to the mixing chamber for initial mixing; then they enter the gap between the grinding roller and the inner wall of the mixing chamber and are mixed under the continuous rotation of the grinding roller; after mixing, the slurry with a gradient distribution is extruded through the discharge port.

Images