Laser fusion-additive deposition synergistic joining method for thermoplastic composite components

Abstract

This invention discloses a laser melting-additive deposition collaborative joining method for thermoplastic composite material components. First, based on the electromagnetic and mechanical performance requirements of the components, a three-dimensional model of a tenon-and-mortise joint with specific geometric features is designed, and corresponding functional components containing the tenon-and-mortise joint structure are prepared. Then, mechanical pre-assembly is performed to form a controllable physically interlocked interface with a continuous joining path. Based on this, a laser melting and additive deposition collaborative device is used to simultaneously heat the composite material with laser and melt it along the tenon-and-mortise joint joining path: the laser acts on the surface of the tenon-and-mortise joint matrix, causing it to partially melt, while the additive material is fed into the melting zone and completely fused, achieving interfacial resin diffusion and gap densification. This invention can significantly improve the electromagnetic stealth continuity, radar wave absorption and shielding performance of the joining area, and ensure the mechanical load-bearing capacity of the joint.

Description

Technical Field

[0001] This invention belongs to the field of composite material joining technology, specifically relating to a laser melting-additive deposition collaborative joining method for thermoplastic composite material components based on the mortise and tenon joint structural path guidance. Background Technology

[0002] Thermoplastic resin-based composites, due to their superior specific strength, specific stiffness, and designable electromagnetic properties, have become key materials for achieving lightweighting and stealth in modern aerospace, high-end naval vessels, and other equipment. However, the integral molding of large and complex components is often limited, making joining technology a bottleneck restricting their performance limits and engineering applications.

[0003] Currently, composite material components mainly rely on two traditional connection technologies: mechanical connections (such as riveting and bolting) and adhesive bonding. Mechanical connections require openings in the component, which not only cuts the load-bearing fibers and introduces severe stress concentration sources, weakening the structural strength, but also creates a strong electromagnetic wave scattering interface at the opening, significantly disrupting the continuity of the component's overall radar stealth and electromagnetic shielding functions. While adhesive bonding avoids openings, it relies on heterogeneous adhesives, whose curing shrinkage may create microscopic defect interfaces. Furthermore, the performance of organic adhesive layers is prone to degradation under humid and aging environments, raising questions about long-term reliability. More importantly, the adhesive layer differs from the composite material itself in electromagnetic properties, forming a significant wave impedance mismatch layer. This causes incident electromagnetic waves to undergo multiple reflections and transmission interference at the front and rear interfaces, similarly severely degrading the component's broadband absorption performance.

[0004] To achieve intrinsic bonding in materials, fusion bonding technologies such as ultrasonic welding and induction welding have emerged. These technologies achieve interfacial fusion by melting and then solidifying the thermoplastic matrix, exhibiting advantages in mechanical properties. However, current research and applications are mostly limited to simple flat plate overlaps. For advanced components with complex three-dimensional morphology, multifunctional partitions, or requiring load-bearing and stealth integration, conventional fusion welding methods face two fundamental challenges: First, it is difficult to achieve uniform and controllable heat input and pressure application in complex curved surfaces or deep grooves, leading to unstable connection quality; second, the process essentially "connects" pre-formed components, without considering the negative impact of the connection interface on the electromagnetic wave propagation path from the design stage, resulting in a high risk of a "cliff-like drop" in functional performance at the connection point.

[0005] Therefore, developing a novel connection method that can simultaneously ensure structural integrity and electromagnetic functional integrity has become a critical technical challenge that needs to be overcome to promote the application of high-performance thermoplastic composite materials in cutting-edge equipment. Summary of the Invention

[0006] The purpose of this invention is to provide a laser melting-additive deposition collaborative joining method for thermoplastic composite material components, in order to overcome the defects of the prior art. The method of this invention combines the flexibility of additive manufacturing in the forming of complex structures, designs mortise and tenon joints to optimize load transfer and functional continuity, and achieves precise interface fusion through heat sources such as laser melting, so as to maintain the broadband radar wave absorption and electromagnetic shielding performance of the component while ensuring the mechanical properties of the joint.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A laser melting-additive deposition co-bonding method for thermoplastic composite components includes the following steps: S1. For the thermoplastic composite functional components to be connected, based on their geometry, force transmission path and electromagnetic performance requirements, design complementary tenon and mortise joint structures and generate a three-dimensional digital model of the tenon and mortise joint structure. S2. Based on the three-dimensional digital model, thermoplastic composite material components with tenons and mortise joints are prepared respectively, namely mortise and tenon joint structures; the two are aligned and mechanically assembled by mortise and tenon joints to form a pre-assembled body with self-positioning and physical interlocking. S3. A laser melting head and an additive deposition nozzle integrated on the same motion platform are used for collaborative operation; the laser melting head is controlled to scan along the joint path of the mortise and tenon joint structure, selectively heating the thermoplastic composite matrix of the interface and adjacent areas to make it reach a molten or semi-molten state; at the same time or slightly delayed, the additive deposition nozzle is controlled to move along the trajectory covering the joint and extrude thermoplastic composite melt compatible with the thermoplastic composite functional component matrix to be connected, so that it is deposited on the heated interface; S4. Under the continuous action of the laser field, the newly deposited melt and the molten part of the thermoplastic composite functional component matrix to be connected permeate and fuse with each other. After cooling and solidification, a dense fused integral connection is formed on the basis of the tenon and mortise mechanical interlocking joint.

[0008] Furthermore, the mortise and tenon joint structure includes, but is not limited to, dovetail type, sawtooth groove type, inverted T-type snap-fit ​​type, or semi-circular snap-fit ​​type.

[0009] Furthermore, the preforming method for the thermoplastic composite material components with tenons and mortise joints includes, but is not limited to, injection molding, compression molding, machining, laser cutting, or additive manufacturing processes.

[0010] Furthermore, the thermoplastic composite functional component to be connected is made of thermoplastic polymer or thermoplastic composite material, and its structure includes a single-layer or multi-layer composite structure; when it is a multi-layer composite structure, it includes at least a wave-transmitting layer, a wave-absorbing functional layer and a reflective layer arranged in sequence, and the reflective layer serves as the substrate of the thermoplastic composite functional component to be connected, and the connection process is carried out on this substrate.

[0011] Furthermore, the material of the wave-transparent layer is a thermoplastic polymer composite material reinforced with glass fiber or silicon nitride fiber; the material of the wave-absorbing functional layer is a thermoplastic polymer composite material containing one or more wave-absorbing agents such as carbon black, carbonyl iron, carbon nanotubes, and chopped carbon fibers; and the reflective layer is a conductive carbon fiber composite material plate or a metal plate.

[0012] Furthermore, the resin matrix of the thermoplastic composite functional component to be connected and the material extruded by the additive deposition nozzle is one or more of polyetheretherketone, polyaryletherketone, polyamide, polyphenylene sulfide, or polyimide.

[0013] Furthermore, the laser melting head is a focused infrared laser or a semiconductor laser; the additive deposition nozzle is a fused deposition modeling extrusion nozzle.

[0014] Furthermore, the scanning power and path of the laser melting head are dynamically matched with the extrusion rate and motion trajectory of the additive deposition nozzle; wherein, the laser scanning speed range is 5-100 mm / s, and the additive deposition speed range is 10-100 mm / s.

[0015] Furthermore, step S3 also includes a process monitoring step: real-time monitoring of the mortise and tenon interface temperature using an infrared thermal imager, and dynamic adjustment of the power or scanning speed of the laser melting head based on the temperature feedback, so that the interface peak temperature is stabilized within the range of 10-50°C above the melting temperature of the base material.

[0016] Furthermore, the mortise and tenon joint structures are connected by a partitioning strategy of first scanning / depositing the inner contour and then scanning / depositing the outer contour; The partitioning strategy of scanning / depositing the inner contour first and then scanning / depositing the outer contour specifically includes: Step 1: Joint pretreatment and positioning Precisely align the mortise and tenon joint structure of the thermoplastic composite components to be connected, clean and preheat the connection area to ensure interface cleanliness and uniform temperature. Step 2: Prioritize scanning / deposition of the inner contour Focusing on the inner contour area of ​​the mortise and tenon joint structure, namely the root of the contact between the tenon and the mortise or the recessed area with complex geometric features, the initial connection point or deposition layer inside the mortise and tenon joint structure is established first by laser melting of the substrate or deposition of materials, ensuring that the material can flow in fully and fill the hard-to-reach inner corner area to form the initial physical anchor point. Step 3: Outer contour scanning / deposition Switch to scanning or deposition of the outer contour of the mortise and tenon joint structure. The deposited material fuses the inner layer with the substrate to build a complete geometric shape of the mortise and tenon joint structure, thereby improving the strength and sealing of the connection interface of the mortise and tenon joint structure. Step 4: Layer-by-layer cycle and final curing For thick-walled structures with multiple layers, repeat the above-mentioned internal-to-external partitioning strategy, building layer by layer until the entire mortise and tenon joint structure is completely deposited. Control the cooling or assist in pressure holding to ensure that the mortise and tenon joint structure is uniformly cured, eliminate internal stress, and form a high-quality connection.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: This invention solves the problems of mechanical damage and stress concentration: the mortise and tenon joint structure avoids the opening required for mechanical connection, fundamentally eliminating the problems of fiber cutting and stress concentration at the hole edge, and improving the load-bearing efficiency of the joint; the laser melting-additive melting deposition synergistic process realizes local micro-area fusion, with a very small heat-affected zone, and the overall mechanical properties of the component are maintained to the greatest extent.

[0018] This invention achieves a superior connection of electromagnetic functions: the mortise and tenon joint itself provides a continuous material transition interface, while laser additive melting further achieves molecular-level fusion of material composition and microstructure. Through design, the electromagnetic parameters of the deposited material can achieve a gradient transition in the connection area, thereby ensuring the continuity of radar absorption, transmission, or shielding functions at the connection point, overcoming the defect of traditional connection methods that inevitably introduce electromagnetic performance "shortcomings".

[0019] This invention breaks through the bottleneck of integrated manufacturing of complex structures: the extreme flexibility of additive manufacturing process makes this method applicable to complex mortise and tenon joints with curved surfaces, internal cavities or three-dimensional interlocking features, providing a brand-new technical approach for the "decomposition into parts, precise connection and functional integration" manufacturing of large, heterogeneous, multifunctional composite material components. Attached Figure Description

[0020] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1A 3D model of an inverted T-shaped snap-fit ​​tenon joint, showing the wave-transmitting layer, gradient wave-absorbing layer, and tenon structure.

[0022] Among them, 1 is the laser melting head; 2 is the additive deposition nozzle; 3 is the thermoplastic composite functional component to be connected; and 4 is the mortise and tenon joint structure.

[0023] Figure 2 Schematic diagram of a device in which a laser melting head and an additive deposition nozzle work together.

[0024] Among them, 5 is the wave-transmitting layer; 6 is the wave-absorbing functional layer; and 7 is the reflective layer.

[0025] Figure 3 Electromagnetic wave absorption performance of inverted T-shaped tenon and mortise functional components connected under TE polarization.

[0026] Figure 4 Electromagnetic wave absorption performance of inverted T-shaped tenon and mortise functional components connected under TM polarization. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] Example 1 Traditional joining methods inevitably lead to mechanical damage and electromagnetic degradation, and existing fusion joining technologies suffer from the core problems of being unable to adapt to complex structures and neglecting functional continuity. This invention aims to develop a novel joining technology for composite materials that integrates structural integrity and electromagnetic functionality, providing a new approach for the manufacture of high-performance multifunctional composite components. Based on this, this invention proposes a synergistic joining method for thermoplastic composite components using laser melting and additive deposition, fundamentally transforming existing joining methods. Its core design idea is: through the interlocking tenon and mortise structure design of composite materials, the optimal mechanical transmission path is constructed macroscopically and a physical positioning is pre-established; then, through the precise synergy of laser and additive manufacturing, the in-situ fusion bonding of the resin matrix at the joining interface and the gradient transition of functional materials are achieved microscopically, ultimately achieving a complete joining effect in which the joining area is almost indistinguishable from the parent material in terms of both mechanical and electromagnetic functions.

[0030] This invention provides a synergistic joining method for laser melting-additive deposition of thermoplastic composite components, comprising: First, based on the actual load conditions and electromagnetic wave absorption / shielding requirements of the thermoplastic composite functional component 3 to be connected, a three-dimensional digital model of the tenon joint structure 4 is designed in reverse (to characterize its three-dimensional geometry) to ensure that it can efficiently transmit complex stress and minimize the reflection and scattering of electromagnetic waves at the connection interface.

[0031] Secondly, thermoplastic composite material components with precision tenons and mortise joints are prepared by means of injection molding, compression molding or additive manufacturing, namely mortise and tenon joint structure 4, and self-positioning assembly is achieved through mortise and tenon mating to form a preliminary mechanically stable body, namely a pre-assembled body with self-positioning and physical interlocking.

[0032] Finally, a specialized device integrating a laser melting head 1 and an additive deposition nozzle 2 is used. The laser melting head 1 controls the laser beam to precisely scan the tenon and mortise joint, causing the extremely thin matrix layer at the interface to melt instantly. Simultaneously, under the guidance of the laser thermal field, the additive deposition nozzle 2 extrudes a composite material melt compatible with the matrix, filling and covering the joint. The new melt and the molten base material deeply fuse and diffuse under the continuous action of the laser, forming a multi-scale, robust bond after cooling, ranging from mechanical interlocking to molecular entanglement.

[0033] Preferably, the mortise and tenon joint structure 4 is designed according to the geometry, force transmission path and functional requirements of the thermoplastic composite functional component 3 to be connected, including but not limited to dovetail type, sawtooth groove type, inverted T-type snap-fit ​​type or semi-circular snap-fit ​​type.

[0034] Preferably, during the laser melting and additive deposition process, the synergistic process parameters of laser melting and additive deposition are dynamically matched. The power density of laser melting is 10. 3 - 105 W / cm², scanning speed of 5-100 mm / s; extrusion speed of additive deposition of 10-100 mm / s. By controlling the temporal and spatial coordination of the laser scanning path and the motion trajectory of the additive deposition nozzle 2, the interface between the newly deposited material and the matrix is ​​kept in a continuously optimized molten state, achieving full diffusion and entanglement of molecular chains.

[0035] Preferably, the laser scanning path and additive deposition path are planned according to the specific geometric shape of the mortise and tenon joint structure 4. For joints with internal angles or locking features, such as dovetail and inverted T-shaped joints, a strategy of scanning and depositing the inner contour first and then the outer contour, and in a layered and partitioned manner (i.e., a partitioned strategy of scanning / depositing the inner contour first and then scanning / depositing the outer contour), is adopted to ensure uniform heat input and complete material filling, and to avoid local overheating or incomplete fusion defects.

[0036] The partitioning strategy of scanning / depositing the inner contour first and then scanning / depositing the outer contour includes: Step 1: Joint pretreatment and positioning The mortise and tenon joint structure 4 of the thermoplastic composite component 3 to be connected is precisely aligned, and the connection area is cleaned and preheated to ensure that the interface is clean and the temperature is uniform.

[0037] Step 2: Prioritize scanning / depositing the inner contour (filling the core connectivity region) Focusing on the inner contour area of ​​the mortise and tenon joint (i.e., the root where the tenon contacts the mortise or the recessed area with complex geometric features). By laser melting the substrate or depositing material, the initial connection points or deposited layers inside the mortise and tenon joint structure 4 are established first, ensuring that the material can fully flow in and fill these hard-to-reach inner corner areas, forming the initial physical anchor points.

[0038] Step 3: Outer contour scanning / deposition (building overall structural strength) Switch to scanning or depositing the outer contour of the exposed surface and surrounding overlapping area of ​​the mortise and tenon joint structure 4. The deposited material fuses the inner layer with the substrate to construct the complete geometric shape of the mortise and tenon joint structure, thereby improving the strength and sealing of the connection interface of the mortise and tenon joint structure 4.

[0039] Step 4: Layer-by-layer cycle and final curing For thick-walled structures with multiple layers, repeat the "inside-outside" partitioning strategy described above, building layer by layer until the entire mortise and tenon joint structure 4 is completely deposited. Controlled cooling or assisted pressure holding ensures uniform curing of the mortise and tenon joint structure 4, eliminating internal stress and forming a high-quality connection.

[0040] Preferably, active thermal management is implemented during the connection process. The temperature field at the tenon-and-mortise interface is monitored in real time using an infrared thermal imager or thermocouples, controlling the peak interface temperature to be 10-50°C above the melting temperature of the base material and below its decomposition temperature. Based on real-time temperature feedback, the laser power or scanning speed is dynamically adjusted to achieve closed-loop process control, ensuring consistent connection quality.

[0041] Preferably, the composite material filaments extruded by the additive deposition nozzle 2 have a resin matrix that is the same as or compatible with the functional component matrix, which is a thermoplastic polymer. The type and content of functional fillers in the composite material filaments can be designed according to the functional requirements of the joint. For example, in the joint area where electromagnetic wave absorption needs to be enhanced, a composite material with a higher content of microwave absorber can be deposited to achieve a gradient or customized enhancement of the joint area's function.

[0042] Example 2 This invention provides a laser melting-additive melt deposition bonding method for functional components made of thermoplastic composite materials, the specific implementation process of which includes: Step 1: Design Goals and Construct a 3D Digital Model Objective: To connect two gradient honeycomb structure plates with mortise and tenon joints, requiring the joint to effectively transfer in-plane shear loads and to make the reflectivity of the joint to X-band radar waves comparable to that of the gradient honeycomb structure plate area.

[0043] like Figure 2 The schematic diagram of the three-dimensional digital model of the mortise and tenon joint shown includes a wave-transmitting layer 5, a wave-absorbing functional layer 6, and a reflective layer 7.

[0044] The wave-transparent layer 5 is located on the top layer and is designed to be 0.4 mm thick. It is used to match the free space impedance and reduce surface reflection.

[0045] The absorbing functional layer 6 is designed as a 7mm thick gradient honeycomb structure (the upper hexagon is 70mm in size, and the middle hollow hexagon is 12mm in size).

[0046] The reflective layer 7 is a conductive carbon fiber reflective plate or a metal plate with a thickness of 0.5 mm. It utilizes its conductive network to achieve total reflection of electromagnetic waves.

[0047] Based on the objectives of impedance matching and structural locking, a tenon-and-mortise joint structure 4 was designed. This specific geometric feature was designed to facilitate assembly and, after assembly, restrict lateral freedom, resulting in a more robust connection.

[0048] Step 2, molding the thermoplastic composite functional component 3 to be connected. Material of wave-transparent layer 5: glass fiber reinforced polyether ether ketone (GF / PEEK) composite filament.

[0049] Materials for the microwave absorbing functional layer 6: carbonyl iron powder / polyether ether ketone (magnetic loss type) and short-cut carbon fiber / carbonyl iron powder / polyether ether ketone (dielectric / magnetic double loss type) composite filaments.

[0050] The reflective layer 7 is a conductive carbon fiber composite material plate or a metal plate, which serves as the substrate for the thermoplastic composite functional component 3 to be connected, and the connection process is carried out on this substrate.

[0051] Deposition materials for bonding: PEEK filaments and GF / PEEK composite filaments that are compatible with the matrix.

[0052] A dual-nozzle fused deposition modeling (FDM) additive manufacturing system was employed. One nozzle printed GF / PEEK to form the wave-transparent layer and partial structure; the other nozzle, based on a 3D digital model, used short-cut carbon fiber / carbonyl iron powder / polyetheretherketone (PEEK) absorbing filaments to print the wave-absorbing honeycomb structure according to a preset program. Ultimately, two complete functional components with precision inverted T-shaped tenons or mortises on their edges were obtained in a single process.

[0053] Step 3, Assembly Surface Connection Mechanical pre-assembly: Two pre-formed functional components are physically assembled using inverted T-shaped snap fasteners along the edges. Due to the geometric constraints of the inverted T-shaped structure, the functional components achieve preliminary mechanical self-locking after being embedded, with no obvious misalignment at the joints.

[0054] Path planning: Using a laser melting device integrated with the printhead, the heating area and scanning path are set to a trajectory that matches the shape of the inverted T-shaped mating surface.

[0055] Connection Process: This connection process is carried out using reflective layer 7 as the substrate. Laser melting head 1 scans the joint surface at 300W power and 20mm / s speed, melting the PEEK matrix to a depth of approximately 0.2mm at the interface. Subsequently (with a lag of approximately 0.5 seconds), for wave-transparent layer 5, the deposition nozzle extrudes molten glass fiber reinforced polyetheretherketone composite filaments at a speed of 15mm / s, while for the wave-absorbing functional layer 6, molten short-cut carbon fiber / carbonyl iron powder / polyetheretherketone composite filaments are extruded to precisely fill the joint area after laser preheating. Continuous laser irradiation ensures that the filling material and the base material melt are fully interfused.

[0056] Process control: Infrared thermal imager monitors interface temperature, and closed-loop control system maintains temperature 10℃-50℃ above the melting temperature of thermoplastic composite material to avoid overheating and decomposition.

[0057] By utilizing the melting and diffusion characteristics of homogeneous materials, gaps in the fit are eliminated, forming a dense, gapless interface that ensures the consistency of mechanical strength and electromagnetic shielding effectiveness in the connection area.

[0058] Application examples Based on the content of Embodiment 2 above, a mortise and tenon functional component was fabricated and verified through an example. Using the X-band as the test frequency band, the specific low-frequency broadband absorption spread verification results are as follows: Using the X-band as the target frequency for absorbing waves, experimental tests were conducted as follows: Figure 2 The electromagnetic absorption performance of the connected gradient cellular functional components is shown. Overall structure as Figure 2 As shown, it includes a wave-transmitting layer 5, a wave-absorbing functional layer 6, and a reflective layer 7. The periodic structure of the wave-absorbing functional layer 6 is as follows: Figure 2 The gradient honeycomb functional unit shown has a wave-transmitting layer 5 made of glass fiber reinforced polyether ether ketone composite filament, a wave-absorbing functional layer 6 made of short-cut carbon fiber / carbonyl iron powder / polyether ether ketone composite filament, and a reflective layer 7 made of conductive carbon fiber composite material plate or metal plate.

[0059] Based on the objectives of impedance matching and structural locking, an inverted T-shaped snap-fit ​​connector was designed. The upper base length of the inverted T was set to 30mm, and the lower base length to 20mm.

[0060] Characteristic parameters of irregular honeycomb structures, such as Figure 2 As shown, l 1=70mm, l 2 = 12mm, t =3.6mm, h 1 = 0.4 mm h 2=7mm, W 1 = 30mm W 2 = 20mm.

[0061] Based on the above parameters, the wave absorption performance of this structure is analyzed: like Figure 3 and Figure 4 As shown, the fixed characteristics of the laser melting-additive melting deposition co-connection method guided by the mortise and tenon joint path avoid the introduction of heterogeneous materials, do not destroy the overall impedance gradient characteristics, and maintain the integrity of the structure. This allows the reflection loss of the structure under the mortise and tenon connection to be below -10dB in the 4.5-18GHz range under TE and TM polarization, and it has good electrical continuity.

[0062] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0063] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0064] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0065] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A laser melting-additive deposition co-bonding method for thermoplastic composite material components, characterized in that, Includes the following steps: S1. For the thermoplastic composite functional component (3) to be connected, based on its geometry, force transmission path and electromagnetic performance requirements, design a complementary tenon and mortise joint structure to generate a three-dimensional digital model of the tenon and mortise joint structure (4). S2. Based on the three-dimensional digital model, thermoplastic composite material components with tenons and mortise joints are prepared respectively, namely, mortise and tenon joint structures (4); the two are aligned and mechanically assembled by mortise and tenon joints to form a pre-assembled body with self-positioning and physical interlocking. S3. A laser melting head (1) and an additive deposition nozzle (2) integrated on the same motion platform are used for collaborative operation; the laser melting head (1) is controlled to scan along the joint path of the mortise and tenon joint structure, and selectively heats the thermoplastic composite matrix of the interface and adjacent area to make it reach a molten or semi-molten state; at the same time or slightly delayed, the additive deposition nozzle (2) is controlled to move along the trajectory covering the joint and extrude thermoplastic composite melt compatible with the matrix of the thermoplastic composite functional component (3) to be connected, so that it is deposited on the heated interface; S4. Under the continuous action of the laser field, the newly deposited melt and the molten part of the matrix of the thermoplastic composite functional component (3) to be connected permeate and fuse with each other. After cooling and solidification, a dense fusion bond is formed on the basis of the tenon and mortise mechanical interlocking joint.

2. The laser melting-additive deposition co-bonding method for thermoplastic composite material components according to claim 1, characterized in that, The mortise and tenon joint structure (4) includes, but is not limited to, dovetail type, sawtooth groove type, inverted T-type snap-fit ​​type or semi-circular snap-fit ​​type.

3. The laser melting-additive deposition co-bonding method for thermoplastic composite material components according to claim 1, characterized in that, The preforming method for thermoplastic composite material components with tenons and mortise joints includes, but is not limited to, injection molding, compression molding, machining, laser cutting, or additive manufacturing processes.

4. The laser melting-additive deposition co-bonding method for thermoplastic composite material components according to claim 1, characterized in that, The thermoplastic composite functional component (3) to be connected is made of thermoplastic polymer or thermoplastic composite material, and its structure includes a single layer or a multi-layer composite structure; when it is a multi-layer composite structure, it includes at least a wave-transmitting layer (5), a wave-absorbing functional layer (6) and a reflective layer (7) arranged in sequence. The reflective layer (7) serves as the substrate of the thermoplastic composite functional component (3) to be connected, and the connection process is carried out on this substrate.

5. The laser melting-additive deposition co-bonding method for thermoplastic composite material components according to claim 4, characterized in that, The material of the wave-transparent layer (5) is a thermoplastic polymer composite material reinforced with glass fiber or silicon nitride fiber; the material of the wave-absorbing functional layer (6) is a thermoplastic polymer composite material containing one or more wave-absorbing agents such as carbon black, carbonyl iron, carbon nanotubes, and short-cut carbon fibers; the reflective layer (7) is a conductive carbon fiber composite plate or a metal plate.

6. The laser melting-additive deposition co-bonding method for thermoplastic composite material components according to claim 1, characterized in that, The thermoplastic composite functional component (3) to be connected and the material extruded by the additive deposition nozzle (2) have a resin matrix of one or more of polyether ether ketone, polyarylether ketone, polyamide, polyphenylene sulfide or polyimide.

7. The laser melting-additive deposition co-bonding method for thermoplastic composite material components according to claim 1, characterized in that, The laser melting head (1) is a focused infrared laser or a semiconductor laser; the additive deposition nozzle (2) is a fused deposition modeling extrusion nozzle.

8. The laser melting-additive deposition co-bonding method for thermoplastic composite material components according to claim 1, characterized in that, The scanning power and path of the laser melting head (1) are dynamically matched with the extrusion rate and motion trajectory of the additive deposition nozzle (2); wherein the laser scanning speed range is 5-100 mm / s and the additive deposition speed range is 10-100 mm / s.

9. The laser melting-additive deposition co-bonding method for thermoplastic composite material components according to claim 1, characterized in that, Step S3 further includes a process monitoring step: real-time monitoring of the mortise and tenon interface temperature using an infrared thermal imager, and dynamic adjustment of the power or scanning speed of the laser melting head (1) based on the temperature feedback, so that the interface peak temperature is stabilized within the range of 10-50°C above the melting temperature of the matrix material.

10. The laser melting-additive deposition co-bonding method for thermoplastic composite material components according to claim 1, characterized in that, The mortise and tenon joint structures (4) are connected by a partitioning strategy of first scanning / depositing the inner contour and then scanning / depositing the outer contour; The partitioning strategy of scanning / depositing the inner contour first and then scanning / depositing the outer contour specifically includes: Step 1: Joint pretreatment and positioning The mortise and tenon joint structure (4) of the thermoplastic composite component (3) to be connected is precisely aligned, the connection area is cleaned and preheated to ensure that the interface is clean and the temperature is uniform. Step 2: Prioritize scanning / deposition of the inner contour Focusing on the inner contour area of ​​the mortise and tenon joint structure (4), namely the root of the tenon and the mortise where they contact each other or the recessed area with complex geometric features, the initial connection point or deposition layer inside the mortise and tenon joint structure (4) is established first by laser melting of the substrate or deposition of the material, so as to ensure that the material can flow in fully and fill the hard-to-reach inner corner area to form the initial physical anchor point. Step 3: Outer contour scanning / deposition Switch to the outer contour scanning or deposition of the mortise and tenon joint structure (4). The deposited material fuses the inner layer with the substrate to construct the complete geometric shape of the mortise and tenon joint structure and improve the strength and sealing of the connection interface of the mortise and tenon joint structure (4). Step 4: Layer-by-layer cycle and final curing For thick-walled structures with multiple layers, repeat the above-mentioned internal-to-external partitioning strategy, build layer by layer until the entire mortise and tenon joint structure (4) is completely deposited, control cooling or assist pressure holding to make the mortise and tenon joint structure (4) uniformly solidify, eliminate internal stress, and form a high-quality connection.

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