Fiber 3D printing device and method thereof

Abstract

The invention discloses a fiber 3D printing device and method, and belongs to the technical field of additive manufacturing equipment. The device comprises a rack, a Z-axis transmission mechanism, an X-Y plane motion system, a feeding system and a control system. According to the Z-axis transmission mechanism, a driving unit is adopted to drive a circulating transmission part to move, so that a printing platform arranged on the circulating transmission part does one-way continuous movement in the Z-axis direction, and infinite-stroke printing is theoretically achieved. The control system is configured to control the Z-axis transmission mechanism to execute precise micro-amplitude reverse adjustment of the local area according to the path planning requirement in the process of executing the global one-way continuous movement so as to achieve backtracking machining of the printed area. According to the method, the size limitation of a construction space of traditional equipment is broken through, interlayer pause is eliminated, the manufacturing efficiency, interlayer bonding strength and fiber continuity of a large complex curved surface fiber reinforced composite material component are remarkably improved, and the method is particularly suitable for integrated forming of high-performance components such as a conformal structure flexible sensor and the like.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing equipment and precision transmission technology, specifically relating to a fiber 3D printing device and method. Background Technology

[0002] Fiber-reinforced composites (FRCs) have broad application prospects in aerospace, automotive manufacturing, biomedicine, and smart structures due to their advantages such as high specific strength, high specific modulus, and strong designability. While traditional composite material manufacturing processes (such as autoclave molding, filament winding, and lay-up molding) are mature, they generally suffer from high mold costs, long production cycles, difficulty in manufacturing complex geometric shapes, and significant material waste. In recent years, continuous fiber 3D printing technology (also known as fused deposition modeling) has emerged as a new digital manufacturing method, enabling controllable fiber orientation and integrated molding of complex structures, attracting widespread attention from academia and industry.

[0003] However, existing continuous fiber 3D printing technologies and equipment still face many severe technical bottlenecks in practical applications, mainly in the following aspects: 1. Limited construction space makes it difficult to achieve integrated molding of large-sized components. Traditional 3D printing equipment typically employs a lead screw and guide rail or rack and pinion transmission mechanism for its Z-axis motion. This rigid transmission structure is limited by the physical length of the mechanical components, resulting in a fixed and finite travel distance for the printing platform. When the printing height exceeds the equipment's travel distance, the model must be divided into several segments for separate printing, and then assembled using adhesive or mechanical connections. This segmented manufacturing method not only increases post-processing steps and time costs but also introduces interface defects and stress concentration points at the joints, severely weakening the overall mechanical properties and structural integrity of large components. For large-scale conformal structures commonly found in the aerospace field, such as stringers, wing skins, or long-range flexible sensors, existing equipment cannot achieve truly "infinitely long" continuous integrated manufacturing.

[0004] 2. Inter-layer pauses lead to low efficiency and poor interface bonding quality. Existing equipment generally employs a "layer-by-layer stacking" motion control strategy. This means that after printing one layer, the Z-axis needs to be raised by one layer height. During this process, the print head often needs to pause its movement or perform idle movements until the platform stabilizes before starting the next layer. This intermittent operation mode has significant drawbacks: First, the downtime between layers reduces overall manufacturing efficiency, especially when printing large-sized components, where non-productive time accounts for a very high percentage. Secondly, and most critically, interlayer pauses cause a significant drop in temperature of the previously deposited material layer. When a new layer of high-temperature melt is applied, the excessive temperature difference between the two layers hinders the full diffusion and entanglement of polymer chains, resulting in a significant reduction in inter-laminar shear strength (ILSS). Experiments show that the interlayer strength of traditional layer-by-layer printing is often only 40%-60% of the strength of the matrix material, becoming a weak point under stress and highly susceptible to delamination failure.

[0005] 3. Path planning for complex curved surface slicing is difficult, and fiber continuity is compromised. When processing components with complex concave-convex surfaces or non-convex polyhedra, traditional slicing software typically employs a stair-step effect. This not only creates a noticeable stair-step effect on the surface, reducing dimensional accuracy and surface quality, but also forces continuous fibers to be cut or causes drastic directional changes at interlayer transitions. Furthermore, traditional filling paths (such as zigzag, concentric offset, etc.) often involve significant empty travel and frequent acceleration, deceleration, and turning. For continuous carbon fiber (CCF), frequent abrupt stops and turns can easily cause fiber buckling, blockage, or even breakage within the nozzle, disrupting the continuity of fiber reinforcement and resulting in significant anisotropy in the mechanical properties of the part, failing to fully realize the reinforcement potential of the continuous fibers.

[0006] 4. Lack of online quality control and defect repair mechanisms Existing continuous printing control systems suffer from rigid logic. Once printing begins, the Z-axis typically only feeds in one direction, lacking flexible local adjustment capabilities. During long-cycle continuous printing, if environmental fluctuations, material inhomogeneity, or path planning errors lead to defects such as porosity, incomplete fusion, or fiber placement deviations, traditional equipment cannot backtrack and repair specific areas without interrupting the overall printing process. Operators often have no choice but to either stop the machine (leading to new defects at the thermal interface) or leave the defects to persist, ultimately resulting in the scrapping of the entire part. This lack of "local monotonicity" control severely restricts the application of continuous printing technology in the manufacturing of high-quality, high-reliability critical components.

[0007] In summary, there is an urgent need to develop a fiber 3D printing device and method that can overcome physical travel limitations, achieve truly continuous and uninterrupted operation, possess adaptive path planning capabilities for complex curved surfaces, and support online local backtracking repair, in order to solve key technical challenges in the manufacturing of large-size, high-performance composite material components. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a fiber 3D printing device and method to address the shortcomings of the prior art, thereby solving the technical problems of interlayer pauses, stroke limitations, low efficiency, and insufficient flexibility in processing complex structures in traditional fiber 3D printing equipment.

[0009] The present invention adopts the following technical solution: A fiber 3D printing apparatus, comprising: frame; The Z-axis transmission mechanism is mounted on the frame and includes a drive unit and a circulating transmission component driven by the drive unit. A printing platform is mounted on the circulating transmission component. The Z-axis transmission mechanism is configured to drive the printing platform to move continuously in one direction along the Z-axis. The XY planar motion system, mounted on the frame, is used to drive the print head to move in the horizontal plane; A feeding system is used to feed printing material to the print head; The control system is electrically connected to the Z-axis transmission mechanism, the XY plane motion system and the feeding system, respectively, and is used to control the Z-axis feed of the printing platform to move synchronously with the planar trajectory of the print head.

[0010] Preferably, the drive unit includes a Z-axis motor, a large gear, and a small gear; The circulating transmission component is a closed-loop belt, which is wrapped around the large gear and the small gear; The printing platform is integrated into the surface of the closed-loop belt; The Z-axis motor is configured to drive the large gear and the small gear to rotate, thereby driving the closed-loop belt to move in a cyclic motion, thus realizing the unidirectional continuous motion of the printing platform along the Z-axis direction.

[0011] Preferably, the XY plane motion system includes: The Y-axis motion assembly includes a Y-axis motor and a Y-axis profile, wherein the Y-axis motor is configured to drive a horizontal movement module to move along the Y-axis profile in the Y-axis direction. The X-axis motion assembly includes an X-axis motor and a horizontal profile guide rail mounted on the horizontal moving module. A tool head is mounted on the horizontal profile guide rail, and the print head is mounted on the tool head. The X-axis motor is configured to drive the tool head to move along the horizontal profile guide rail in the X-axis direction.

[0012] Preferably, the horizontal profile guide rail includes a fixing block, a timing belt, a pulley, and a guide rail; The fixing block is connected to the timing belt and is used to fix the tool head; When the pulley rotates, it drives the synchronous belt to run, causing the fixed block to slide within the guide rail, thereby driving the print head to move in the X-axis direction.

[0013] Preferably, the printhead includes, in sequence along the material flow direction, a heat sink, a throat, a thermally conductive aluminum block, and a nozzle; A cooling fan is provided at the heat sink to cool the incoming solid wires; The thermally conductive aluminum block is used to heat and melt the wire passing through the throat. The nozzle is used to extrude molten material and deposit it onto the printing platform.

[0014] Preferably, the feeding system includes a feeding motor, and the printing material includes continuous carbon fiber and a thermoplastic matrix material; The thermoplastic matrix material is selected from at least one of TPU, PLA or nylon; The feed motor is configured to simultaneously feed the continuous carbon fiber and the thermoplastic matrix material to the print head for melt co-extrusion.

[0015] Preferably, the device is configured to fabricate a fiber-reinforced composite conformal flexible vibration sensor; In this structure, the continuous carbon fiber serves as the reinforcing phase, and the thermoplastic matrix material serves as the matrix phase. The materials are deposited layer by layer on the printing platform, which is undergoing unidirectional continuous motion, to form a continuous structure without interlayer pauses.

[0016] Preferably, the control system is further configured to execute a local monotonicity control strategy: During the process of controlling the printing platform to perform global unidirectional continuous motion, the Z-axis transmission mechanism is controlled to perform precise micro-amplitude reverse adjustment within a specific time period according to the preset path planning instructions; The precise micro-amplitude reverse adjustment causes the specific area already printed on the printing platform to return to the working position of the print head for secondary processing, and immediately resumes the unidirectional continuous movement after the secondary processing is completed.

[0017] Preferably, it also includes a heated bed, which is disposed inside or below the circulating transmission component and located below the deposition area of ​​the printing platform; The heated bed is electrically connected to the control system and is used to heat and maintain the temperature of the printing material deposited on the printing platform.

[0018] Another technical solution of the present invention is a fiber 3D printing method, applied to the aforementioned fiber 3D printing equipment, comprising the following steps: S1. Use the surface unfolding module to unfold the imported 3D model into a 2D plane and generate a non-overlapping planar unfolded diagram; specifically, this includes using a discretization method to convert the surface of the 3D model into a triangular mesh, using a binary tree traversal algorithm to find adjacent faces, and using rotation and translation transformations to make adjacent faces coplanar and aligned along shared edges. S2. Based on the planar unfolded diagram obtained in step S1, the boundary coordinate points are extracted according to the Euler path sequence, and the Hilbert curve is used as a space filling algorithm to fill the internal path, generating a continuous printing path without idle movement. S3. Convert the print path generated in step S2 into executable G code and load it into the control system; S4. The control system, based on the G code, controls the feeding system to feed material to the print head (12), controls the XY plane motion system to drive the print head (12) to move in the horizontal plane, and controls the Z-axis transmission mechanism to drive the printing platform (11) to move continuously in one direction along the Z-axis. In this process, according to the path planning requirements, the printing platform (11) is controlled to make precise micro-amplitude reverse adjustments in local areas during the execution of the unidirectional continuous motion, so as to realize the back-processing of the printed area; S5. After the printing task is completed, control all moving parts to reset.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects: A fiber 3D printing device overcomes the limitations of traditional lead screw Z-axis travel by employing cyclic transmission components and unidirectional continuous motion, and achieves coordinated printing platform feed and print head trajectory through synchronous control. It establishes a foundational framework for unlimited travel and continuous printing at the overall machine level, eliminating inter-layer pauses and solving the problems of limited forming space, low printing efficiency, and weak inter-layer bonding in traditional equipment. The modular design reduces assembly and maintenance costs, with clear division of labor and stable coordination among systems. It is suitable for the integrated molding of large-sized components while retaining structural expansion space, and is compatible with printing various fibers and thermoplastic materials. This provides fundamental hardware support for the rapid manufacturing of large composite material components, solving the industry pain point of the inability to integrally mold large-sized parts.

[0020] Furthermore, a Z-axis motor, large and small gears, and a closed-loop belt drive are employed, integrating the printing platform onto the belt surface. Stable unidirectional continuous motion is achieved through gear meshing and the circulating belt. The gear set has a precise transmission ratio, ensuring uniform and smooth Z-axis feed and avoiding vibration and displacement deviation. The closed-loop belt has no upper limit on travel, completely eliminating the physical length constraints of traditional guide rails / lead screws, and meeting the requirements for continuous printing of ultra-long components. The belt drive offers moderate flexibility, low noise, and fast response, achieving high-precision positioning in conjunction with the gear drive, facilitating subsequent micro-adjustments. This simplifies the transmission chain, reduces the number of parts, improves reliability and service life, and lowers manufacturing and debugging costs. Simultaneously, the lightweight belt platform with low moment of inertia is beneficial for high-speed continuous printing.

[0021] Furthermore, a separate architecture is adopted, with the Y-axis component driving the horizontal movement module and the X-axis component driving the tool head. The Y-axis motor moves the entire horizontal module along the Y-axis profile, while the X-axis motor drives the tool head and printhead along the horizontal profile guide rail. This decoupling of X and Y axis movements avoids motion interference and improves trajectory control accuracy and response speed. The horizontal profile guide rail provides stable support and guidance, ensuring rigidity and stability under high-speed movement. The separate drive reduces single-axis load, improves movement speed and positioning accuracy, and is suitable for rapid tracking of complex continuous paths such as Hilbert curves. The modular structure facilitates installation and calibration, is compatible with different sizes of printheads and tools, and expands the applicable scenarios of the equipment.

[0022] Furthermore, it consists of a fixed block, a synchronous belt, pulleys, and a guide rail. The synchronous belt drives the fixed block and the tool head to slide along the guide rail. The synchronous belt transmission has high precision and small backlash, ensuring accurate X-axis positioning; the fixed block rigidly connects the tool head, preventing loosening and displacement deviation; the guide rail provides linear guidance, reducing friction and vibration, and ensuring stable high-speed movement. It is simple, reliable, and easy to maintain, with a lower cost than linear motors and ball screws, while meeting the high-precision requirements of continuous printing. The synchronous drive of the pulleys has a fast response, facilitating real-time linkage with the control system and adapting to rapid continuous path switching.

[0023] Furthermore, a heat sink, cooling fan, throat, thermally conductive aluminum block, and nozzle are sequentially arranged along the material flow path. The cooling fan pre-cools the solid filament, while the thermally conductive aluminum block rapidly melts the material. Segmented temperature control prevents premature softening and blockage of the filament, ensuring smooth feeding. The throat provides stable thermal insulation, preventing heat transfer from affecting feeding rigidity. The thermally conductive aluminum block provides uniform heating, ensuring complete material melting and good extrusion continuity. It is compatible with co-extrusion of continuous carbon fiber and thermoplastic matrix, avoiding fiber entanglement and material breakage, and improving the molding quality of composite materials. The heat dissipation system is efficient and stable, extending the life of the printhead; the nozzle outputs material uniformly, ensuring consistent filament width and interlayer bonding.

[0024] Furthermore, a feeding motor is used to transport continuous carbon fiber (CCF) and the thermoplastic matrix, supporting simultaneous co-extrusion. Continuous carbon fiber enhances the strength, modulus, and structural stability of the component, while the thermoplastic matrix provides good formability and toughness, making it suitable for the fabrication of multifunctional structural components. The independent feeding motor provides precise and fast feeding, and the feeding rate and extrusion volume can be adjusted in real time to match the printing speed, ensuring uniform fiber arrangement. The material system is widely compatible, and the matrix material can be switched according to requirements to meet different mechanical and functional needs. Simultaneous co-extrusion achieves uniform bonding between the reinforcing phase and the matrix phase, improving the isotropy of the composite material and reducing defects.

[0025] Furthermore, a flexible vibration sensor with a conformal structure made of fiber-reinforced composite material was fabricated using CCF as the reinforcing phase and thermoplastic material as the matrix, formed without interlayer pauses on a continuous motion platform. Integrated continuous molding eliminates weak interlayer interfaces, improving the sensor's structural integrity and mechanical stability; the conformal molding adapts to complex curved surfaces, conforming to the surface of the object being measured, thus improving detection accuracy. Continuous fibers enhance the sensor's conductivity, sensing, and mechanical properties, extending its service life; the absence of interlayer structures reduces stress concentration and improves fatigue resistance. This approach integrates structural manufacturing and functional device fabrication, simplifying the process, shortening the production cycle, and reducing costs.

[0026] Furthermore, based on global unidirectional continuous motion, precise micro-amplitude reverse adjustment is achieved, allowing for secondary processing of already printed areas. This overcomes the limitations of traditional equipment in localized correction, improving interface bonding strength and forming accuracy, and optimizing the forming quality of complex structures. Micro-amplitude reverse adjustment does not disrupt global continuous motion or cause inter-layer pauses, ensuring printing efficiency. Real-time dynamic coordination of Z-axis speed and direction adapts to complex paths and localized reinforcement needs, enhancing processing flexibility. The control algorithm features fast response, accurate positioning, and high backtracking precision, enabling enhanced processing of critical areas.

[0027] Furthermore, a heated bed is added, located inside / below the circulating drive components and below the deposition area of ​​the printing platform. It is electrically connected to the control system for heating and insulation. The heated bed ensures uniform temperature in the printing area, reducing material shrinkage, deformation, and warping, and improving interlayer adhesion and dimensional accuracy. It is suitable for printing thermoplastic materials, optimizing the curing process and improving density and mechanical properties. The temperature control system adjusts in real time to adapt to the processing requirements of different materials, improving molding stability. The heated bed is compactly arranged, does not interfere with the circulating drive and motion system, and does not increase the equipment size.

[0028] A fiber 3D printing method employs triangular mesh discretization, binary tree traversal, and rotational translation transformations to achieve non-overlapping unfolding of complex surfaces, resolving the path overlap and interference problem of concave / convex surfaces. Hilbert curves and Euler paths generate continuous paths without idle paths, reducing start-stop defects and improving fiber continuity. Local monotonicity control enables the combination of continuous printing and backtracking, improving efficiency and accuracy. The overall method is concise and logically clear, optimizing the entire process from model processing to molding, and is suitable for the integrated continuous manufacturing of large-size complex components. This method eliminates inter-layer pauses, improves production efficiency, enhances the mechanical properties and molding accuracy of components, and is applicable to the rapid manufacturing of high-end composite material components, expanding the scope of 3D printing geometry and dimensional applicability.

[0029] In summary, this invention overcomes size limitations through an infinite-stroke Z-axis mechanism, solves complex geometric forming challenges by utilizing surface unfolding and one-stroke path planning, and pioneers a local monotonicity control strategy to achieve quality backtracking optimization. The entire solution enables efficient, continuous, and integrated high-performance manufacturing of large, complex fiber composite material components.

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the following description of the relative embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart of the present invention; Figure 2 This is a picture of a fiber 3D printing device. Figure 3 A model diagram of a fiber 3D printing equipment; Figure 4 Explanation of the local monotonicity of fiber 3D printing equipment; Figure 5 A schematic diagram of a horizontal profile guide rail for a fiber 3D printing equipment; Figure 6 This is a model diagram of the print head for a fiber 3D printing device.

[0033] The components are as follows: 1. Feed motor; 2. Y-axis profile; 3. Vertical slider; 4. X-axis motor; 5. Y-axis motor; 6. Heated bed; 7. Large gear; 8. Small gear; 9. Belt; 10. Z-axis motor; 11. Printing platform; 12. Print head; 13. Tool head; 14. Horizontal profile guide rail; 51. Fixing block; 52. Synchronous belt; 53. Pulley; 54. Guide rail; 61. Heat sink; 62. Cooling fan; 63. Throat; 64. Thermally conductive aluminum block; 65. Nozzle. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0038] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0039] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0040] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0041] This invention provides a fiber 3D printing device and method. The transmission mechanism adopts a closed-loop belt drive configuration consisting of an active rotating drum driven by a servo motor and an auxiliary guide wheel. Through precise motion control, the printing platform fixed on the belt achieves unidirectional continuous linear motion in the Z-axis direction, thus breaking through the travel limitations of traditional equipment. It possesses local monotonicity control capability, meaning that while maintaining global continuous unidirectional motion along the Z-axis, the printing platform is allowed to perform precise micro-adjustments in local areas according to path planning requirements, enabling backtracking processing of already printed areas. Its workflow includes: slicing the 3D model and discretizing it into triangular meshes; applying a Hilbert curve-based space filling algorithm within each slice layer; controlling the movement of the print head in the XY plane in real time according to the generated continuous printing path; and dynamically coordinating the belt feed speed and direction in the Z-axis based on a local monotonicity strategy, achieving a continuous operation mode of printing and conveying simultaneously with backtracking optimization. This invention further improves the interfacial bonding strength and forming accuracy of components through local monotonicity control, making it suitable for high-performance rapid manufacturing of large-size fiber composite material components.

[0042] Please see Figure 1The present invention discloses a fiber 3D printing apparatus and method, comprising the following steps: S1. Use the surface unfolding module to unfold the imported 3D model into a 2D plane: Use the discretization method to convert the surface of the 3D model into a triangular mesh, select the starting triangular facet as the root node, use the binary tree traversal algorithm to find adjacent faces, and use rotation and translation transformations to make adjacent faces coplanar and aligned along the shared edge. Iterate until all faces are unfolded into the same plane, generating a non-overlapping planar unfolded map.

[0043] Mesh simplification is achieved using an edge collapse algorithm based on Quadratic Error Metrics (QEM). The core of this algorithm is to calculate the value of each edge (connecting vertices). and Collapse into a new apex The resulting geometric error is defined by the sum of squared distances from the vertex to its associated triangular facet plane, and the error matrix Q is calculated as shown in equation (1): (1) in, Let be the fundamental quadratic error matrix of plane p.

[0044] Preferred collapse causes Δ( The smallest edge is used to significantly reduce the number of triangular facets and the complexity of subsequent processing, while preserving the geometric features and contours of the original surface to the greatest extent possible, thus achieving effective simplification of the model.

[0045] To find adjacent faces in the simplified model, the vertex index information of all triangular faces is first read, and the shared edges are determined and located by calculating the intersection of the vertex index sets.

[0046] Specifically, for two surfaces and If the intersection of their vertex index sets contains exactly two vertices, then these two faces are determined to share an edge formed by these two vertices. This method is a key step in identifying the topological adjacency relationship of the model and laying the foundation for subsequent face unfolding. A further improvement of this invention is that after discretization, adjacent faces are rotated to become parallel. For two adjacent faces sharing an edge... and First, calculate their respective unit normal vectors. and To make the noodles Rotate to face For parallelism, it is necessary to calculate the unit vector k of the rotation axis and the rotation angle θ, and the calculation formulas are shown in equations (2) and (3): (2) (3) Subsequently, the Rodriguez rotation formula was applied to calculate the surface. any vertex Position after rotation Thus, the surfaces are coplanar, as shown in equation (4): (4) After discretization, the two parallel surfaces are rotated, and a translation transformation is used to ensure that their shared edges precisely coincide. After the rotation transformation makes the two planes parallel, the positional deviation of the shared vertex before and after the rotation is calculated to obtain the translation vector. Let the shared vertex be on the surface... Let the coordinates be A on the plane. The corresponding coordinates after rotation are A', and the translation vector t is calculated as shown in equation (5): (5) Apply this translation vector to the surface By aligning all vertices of the two planar sheets along the shared edge, a single unfolding step can be completed.

[0047] S2. Based on the unfolded two-dimensional plane obtained in step S1, perform continuous path planning and extract the boundary coordinate points of the unfolded diagram based on the Euler path sequence. Use Hilbert curves as the space filling algorithm to fill the path inside the unfolded diagram and generate a continuous printing path with no idle movement and no sudden change in direction.

[0048] A random selection mechanism is introduced when traversing all faces of a polyhedron structure to determine the global unfolding sequence. The algorithm randomly selects one of four classic binary tree traversal strategies—preorder traversal, inorder traversal, postorder traversal, and level-order traversal—and applies it to the current or local face traversal process. This enables the generation of diverse 2D unfolding sequence sequences, providing multiple possible solutions for adapting to different continuous path planning requirements and optimizing material layout.

[0049] S3. Based on the continuous printing path obtained in step S2, the path coordinates are combined with printing parameters (such as speed and extrusion amount) and converted into G-code that can be executed by the CNC system of the fiber 3D printing equipment.

[0050] S4. Based on the G-code obtained in step S3, the control system loads the generated G-code into the integrated motion control motherboard of the device, starts printing, and drives the print head 12 to move along the G-code trajectory in the XY plane; drives the z-axis motor 10 to make the printing platform 11 move continuously downward (in the negative direction of the Z-axis) at a constant speed, wherein micro-reverse adjustment of specific areas is achieved through local monotonicity control to support backtracking processing requirements; controls the print head 12 to extrude fiber composite material, which is stacked layer by layer on the continuously moving printing platform 11. Due to the continuous movement of the platform, there is no interruption between layers in the printing process.

[0051] By combining continuous carbon fiber (CCF) and TPU matrix materials using fiber 3D printing technology, and based on the two-dimensional pattern obtained by the aforementioned surface unfolding method, a high-performance fiber-reinforced composite conformal flexible vibration sensor is fabricated on the infinite Z-axis device described in this invention, achieving integrated rapid prototyping of the sensor structure. This method integrates the conformal design of complex surfaces, composite material preparation, and functional device manufacturing into a continuous printing process, simplifying the fabrication process while offering excellent cost-effectiveness, higher production efficiency, and faster manufacturing speed.

[0052] S5. After printing is complete, the system resets and the fiber 3D printing equipment enters standby mode, at which point the molded part can be removed.

[0053] Please see Figure 2 and Figure 3 This invention discloses a fiber 3D printing device, comprising a frame structure, an infinite-stroke Z-axis transmission mechanism, an XY-plane motion system, and a feeding system. The frame structure is a Y-axis profile 2, which constitutes the main support of the device. The infinite-stroke Z-axis transmission mechanism is divided into a drive unit and a transmission unit. The drive unit includes a Z-axis motor 10 and its driven large gear 7, small gear 8, and belt 9. The transmission unit is a closed-loop belt surrounding a heated bed 6, i.e., the printing platform 10. When the infinite-stroke Z-axis transmission mechanism is working, the Z-axis motor 10 drives the large gear and small gear 8 to rotate, thereby moving the large gear 7 and belt 9. This drives the closed-loop belt to circulate, enabling the printing platform 11 to achieve continuous linear motion in one direction along the Z-axis guide rail. Simultaneously, the transmission mechanism possesses local monotonicity adjustment capabilities, allowing for micro-amplitude reverse motion on the basis of continuous global motion. The XY planar motion system includes an X-axis motion system where the tool head 13 is driven by the X-axis motor 4 to move along the X-axis, a Y-axis motion system where the horizontal profile guide rail 14 is driven by the Y-axis motor 5 to move along the Y-axis, and a print head 12 mounted on the XY motion system. The feeding system is a feeding motor 1, used to convey continuous carbon fiber (CCF) and other matrix materials.

[0054] By using a servo motor to drive a pinion, which in turn drives a large gear and a belt, a high-strength closed-loop belt (which is the printing platform) is driven to circulate. This achieves unidirectional, continuous, and infinitely long linear feed motion in the Z-axis direction, completely eliminating the travel limitations of traditional lead screws or guide rails. At the same time, this transmission mechanism has local monotonicity control capabilities, which can perform precise micro-amplitude reverse adjustments according to path planning requirements while maintaining continuous unidirectional motion globally, enabling backtracking processing of the printed area.

[0055] Please see Figure 4The local monotonicity control strategy uses three color-coded areas to indicate its working status: red indicates the portion that has been printed and moved out of the conveyor belt's reach; blue indicates the portion that has been printed but is still within the conveyor belt's working range; and yellow indicates the backtracking processing area undergoing secondary processing. The specific implementation steps are as follows: First, the printhead completes the initial printing of the red area at the platform's starting position; When the blue area was printed subsequently, the red area had already moved out of the reach of the conveyor belt as the printing platform moved in one direction and could no longer be reached. The printing platform continuously transports unprinted areas to the working position, forming a blue area within the working range of the conveyor belt; When interface performance needs to be enhanced, the blue area is repositioned below the printhead by slight reverse adjustment along the Z-axis, entering the secondary processing state shown in the yellow area. After processing is completed, global unidirectional motion is immediately restored.

[0056] Please see Figure 5 The horizontal profile guide rail 14 mainly consists of a fixing block 51, a timing belt 52, a pulley 53, and a guide rail 54. Specifically, the fixing block 51 is located on the timing belt and is used to fix the position of the lower tool head 13. When the pulley 53 rotates, it drives the timing belt 52 to run and move stably in the guide rail 54, thereby realizing the movement of the print head 12 on the y-axis.

[0057] Please see Figure 6 The printhead 12 includes a heat sink 61, a cooling fan 62, a throat 63, a thermally conductive aluminum block 64, and a printhead 65. The specific implementation steps are as follows: S1. Pre-cooling: When the solid wire enters the printhead 12, it first passes through the heat sink 61 area and is strongly cooled by the cooling fan 62 to ensure that the wire remains rigid before reaching the heating zone.

[0058] S2. Heating and melting: The wire continues to descend and enters the high-temperature heating zone of the heat-conducting aluminum block 64 through the throat 63, where it is rapidly heated and melted into a viscous flow state.

[0059] S3. Extrusion and molding: Under pressure, molten material is extruded from the micro-holes of nozzle 65 and deposited on the printing platform or the previous deposition layer. It then cools and solidifies, and is built up layer by layer to form a three-dimensional solid.

[0060] The printing equipment control system is implemented by an integrated motion control motherboard.

[0061] The main functions of this motherboard include: receiving and parsing G-code instructions; Synchronous control: The movement of the x-axis motor 4, y-axis motor 5 and z-axis motor 10 is coordinated in real time to ensure that the path of the print head 12 in the XY plane is precisely matched with the feed speed of the printing platform 11 in the Z axis, realizing a continuous operation mode of printing and feeding at the same time. In this mode, through the local monotonicity control strategy, while maintaining the global continuous unidirectional movement of the printing platform, the backtracking processing of local areas is realized according to the path planning requirements; the feeding rate of the feed motor 1 and the extrusion amount of the print head 12 are controlled.

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0063] Experimental comparison data (efficiency and mechanical properties): Improved molding efficiency: For linear components with a length of 2 meters, traditional layer printing equipment (layer height 0.2mm, requiring a stop to change layers) takes about 120 minutes; using the continuous printing mode of this invention (Z-axis speed 5mm / s, no interruption between layers), it only takes 40 minutes, improving manufacturing efficiency by 200%.

[0064] Interlaminar shear strength (ILSS): The printed CF / TPU samples were tested. Traditional layer-by-layer printing resulted in rapid interlayer cooling and weak bonding, with an average ILSS of 28 MPa. The present invention uses continuous motion combined with heated bed insulation and local backtracking processing, resulting in more complete interlayer fusion and an ILSS of 42 MPa, an increase of 50%, which is close to the level of autoclave molding process.

[0065] Dimensional stability: When printing a 1.5-meter-long beam, traditional equipment causes the end to warp and deform by up to 3.5 mm due to accumulated errors and thermal stress. This invention uses a closed-loop belt drive to eliminate accumulated errors, and with real-time temperature control, the total deformation is controlled within 0.4 mm.

[0066] In summary, this invention, a fiber 3D printing device and method, effectively solves the technical challenges in manufacturing complex curved surface components through an innovative combination of an infinite-stroke Z-axis transmission mechanism and intelligent continuous path planning. The innovative infinite-stroke Z-axis mechanism enables the device to manufacture theoretically infinitely long components, making it particularly suitable for the integrated molding of large, long-sized fiber composite structures. Employing a unique surface unfolding algorithm, the device can handle models containing complex concave and convex surfaces, expanding the geometric applicability of 3D printing. Through one-stroke fiber path planning, the continuity and consistency of fiber orientation are improved, thereby enhancing the isotropic mechanical properties of composite components and reducing defects caused by frequent starts, stops, and idle movements. This technology not only improves the manufacturing efficiency of complex curved surface components but also expands the application scope of 3D printing technology in fields such as flexible electronics and aerospace, and is particularly suitable for the integrated molding manufacturing of large, complex structural parts.

[0067] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A fiber 3D printing device, characterized in that, include: frame; The Z-axis transmission mechanism is mounted on the frame and includes a drive unit and a circulating transmission component driven by the drive unit. A printing platform (11) is mounted on the circulating transmission component. The Z-axis transmission mechanism is configured to drive the printing platform (11) to move continuously in one direction along the Z-axis. The XY planar motion system, mounted on the frame, is used to drive the print head (12) to move in the horizontal plane; A feeding system for supplying printing material to the print head (12); The control system is electrically connected to the Z-axis transmission mechanism, the XY plane motion system and the feeding system respectively, and is used to control the Z-axis feed of the printing platform (11) to move synchronously with the plane trajectory of the printing head (12).

2. The fiber 3D printing apparatus according to claim 1, characterized in that, The drive unit includes a Z-axis motor (10), a large gear (7), and a small gear (8). The circulating transmission component is a closed-loop belt, which is wrapped around the large gear (7) and the small gear (8); The printing platform (11) is integrated into the surface of the closed-loop belt; The Z-axis motor (10) is configured to drive the large gear (7) and the small gear (8) to rotate, thereby driving the closed-loop belt to move in a cyclic motion, thus realizing the unidirectional continuous motion of the printing platform (11) along the Z-axis direction.

3. The fiber 3D printing apparatus according to claim 1, characterized in that, The XY plane motion system includes: The Y-axis motion assembly includes a Y-axis motor (5) and a Y-axis profile (2), wherein the Y-axis motor (5) is configured to drive a horizontal moving module to move along the Y-axis profile (2) in the Y-axis direction; The X-axis motion assembly includes an X-axis motor (4) and a horizontal profile guide rail (14) mounted on the horizontal moving module. A tool head (13) is mounted on the horizontal profile guide rail (14), and the print head (12) is mounted on the tool head (13). The X-axis motor (4) is configured to drive the tool head (13) to move along the horizontal profile guide rail (14) in the X-axis direction.

4. The fiber 3D printing apparatus according to claim 3, characterized in that, The horizontal profile guide rail (14) includes a fixing block (51), a timing belt (52), a pulley (53), and a guide rail (54). The fixing block (51) is connected to the timing belt (52) and is used to fix the tool head (13). When the pulley (53) rotates, it drives the synchronous belt (52) to run, causing the fixed block (51) to slide in the guide rail (54), thereby driving the print head (12) to move in the X-axis direction.

5. The fiber 3D printing apparatus according to claim 1, characterized in that, The printhead (12) includes, in sequence along the material flow direction, a heat sink (61), a throat (63), a heat-conducting aluminum block (64), and a nozzle (65). A cooling fan (62) is provided at the heat sink (61) to cool the incoming solid wire; The heat-conducting aluminum block (64) is used to heat and melt the wire passing through the throat (63); The nozzle (65) is used to extrude molten material onto the printing platform (11).

6. The fiber 3D printing apparatus according to claim 1, characterized in that, The feeding system includes a feeding motor (1), and the printing material includes continuous carbon fiber and thermoplastic matrix material; The thermoplastic matrix material is selected from at least one of TPU, PLA or nylon; The feed motor (1) is configured to simultaneously feed the continuous carbon fiber and the thermoplastic matrix material to the print head (12) for melt co-extrusion.

7. The fiber 3D printing apparatus according to claim 6, characterized in that, The device is configured to prepare a flexible vibration sensor with a conformal structure of fiber-reinforced composite material. In this process, the continuous carbon fiber serves as the reinforcing phase, and the thermoplastic matrix material serves as the matrix phase. The carbon fiber is deposited layer by layer on the printing platform (11) which is making the unidirectional continuous motion through the print head (12) to form a continuous structure without interlayer pauses.

8. The fiber 3D printing apparatus according to claim 1, characterized in that, The control system is further configured to execute a local monotonic control strategy: During the process of controlling the printing platform (11) to perform global unidirectional continuous motion, the Z-axis transmission mechanism is controlled to perform precise micro-amplitude reverse adjustment within a specific time period according to the preset path planning instructions; The precise micro-amplitude reverse adjustment causes the specific area already printed on the printing platform (11) to return to the working position of the print head (12) for secondary processing, and immediately resumes the unidirectional continuous motion after the secondary processing is completed.

9. The fiber 3D printing apparatus according to claim 1, characterized in that, It also includes a heated bed (6), which is disposed inside or below the circulating transmission component and located below the deposition area of ​​the printing platform (11); The heated bed (6) is electrically connected to the control system and is used to heat and keep warm the printing material deposited on the printing platform (11).

10. A fiber 3D printing method, applied to the fiber 3D printing equipment as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Use the surface unfolding module to unfold the imported 3D model into a 2D plane and generate a non-overlapping planar unfolded diagram; specifically, this includes using a discretization method to convert the surface of the 3D model into a triangular mesh, using a binary tree traversal algorithm to find adjacent faces, and using rotation and translation transformations to make adjacent faces coplanar and aligned along shared edges. S2. Based on the planar unfolded diagram obtained in step S1, the boundary coordinate points are extracted according to the Euler path sequence, and the Hilbert curve is used as a space filling algorithm to fill the internal path, generating a continuous printing path without idle movement. S3. Convert the print path generated in step S2 into executable G code and load it into the control system; S4. The control system, based on the G code, controls the feeding system to feed material to the print head (12), controls the XY plane motion system to drive the print head (12) to move in the horizontal plane, and controls the Z-axis transmission mechanism to drive the printing platform (11) to move continuously in one direction along the Z-axis. In this process, according to the path planning requirements, the printing platform (11) is controlled to make precise micro-amplitude reverse adjustments in local areas during the execution of the unidirectional continuous motion, so as to realize the back-processing of the printed area; S5. After the printing task is completed, control all moving parts to reset.

Images