System and method for preparing aerospace complex component through silk powder composite L-DED

Abstract

The invention discloses a system and method for preparing an aerospace complex component through wire powder composite L-DED, and relates to the technical field of laser quantitative deposition, the system comprises a wire feeding module, a laser head and a nozzle which are coaxially arranged, and the laser head is used for emitting a laser beam; a powder feeding channel is arranged in the nozzle and used for conveying powder provided by the powder feeding module. The system further comprises a sensing module, the sensing module is used for obtaining key parameters of a molten pool, wire feeding and laser in real time and transmitting the key parameters to the central controller, and the central controller is used for regulating and controlling the wire feeding module and / or the powder feeding module to work. Laser-wire-powder coaxial arrangement is adopted, and modular design is matched, so that rapid switching or composite use of wire and powder machining can be achieved, and the accuracy and precision of wire machining and powder machining are guaranteed; a large-area continuous area adopts wire deposition, a transition area adopts wire-powder composite deposition, and a local detail area adopts powder deposition, so that the machining precision and efficiency of the component are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser quantitative deposition, and in particular to a system and method for preparing complex aerospace components using silk powder composite L-DED. Background Art

[0002] Complex aerospace components (such as engine blades, fuselage cavities and thin-walled structures) are often difficult to process under traditional processing technology due to their complex geometric shapes, local fine structures and high performance requirements. These components are prone to problems such as insufficient processing accuracy, concentrated thermal stress, difficult cutting and substandard surface quality during processing. Laser directed energy deposition (L-DED) technology can cope with these difficulties and realize the integrated manufacturing of complex components by virtue of its layer-by-layer deposition advantages. However, the current L-DED equipment mainly uses a single powder or a single wire as raw material. The processing accuracy of a single wire is limited by the wire diameter and is not suitable for fine processing requirements of local extremely thin parts. Although the single powder method can achieve higher processing accuracy, it has the disadvantages of large material waste, poor melt pool stability, and easy generation of pores and defects during deposition.

[0003] There are some solutions that use wire and powder switching in the prior art. For example, a Chinese patent (publication number CN119549735A, publication date 2025.03.04) discloses a method for additive manufacturing of titanium alloys by silk-powder collaborative multimodal laser coupling. The material is transported by combining wire feeding and powder feeding. Wire feeding is used to quickly manufacture large structures in parts, and powder is used to manufacture relatively fine structures. Titanium alloy parts can be prepared efficiently and accurately. Although this solution provides a solution for local fine structures, there are transition areas for complex aerospace components. The above solution cannot guarantee the requirements of smoothness and connectivity for complex components. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a system and method for preparing complex aerospace components by silk-powder composite L-DED, which adopts a coaxial setting of laser-silk-powder and cooperates with modular design to achieve rapid switching or composite use of silk and powder processing, thereby ensuring the accuracy and precision of wire processing and powder processing; wire deposition is used in large continuous areas, silk-powder composite deposition is used in transition areas, and powder deposition is used in local detail areas, thereby improving the processing accuracy and efficiency of components.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions: In a first aspect, an embodiment of the present invention provides a system for preparing complex aerospace components by using silk powder composite L-DED, comprising: A wire feeding module, a laser head and a nozzle are coaxially arranged, wherein the laser head is used to emit a laser beam; the nozzle has a built-in powder feeding channel, and the powder feeding channel is used to transport powder material provided by the powder feeding module; The sensing module is used to obtain the key parameters of the molten pool, wire feeding and laser in real time, and transmit the key parameters to the central controller, which is used to regulate the operation of the wire feeding module and / or the powder feeding module.

[0006] As a further implementation, the wire feeding module includes a wire feeding wheel group, a guide tube and a straightening mechanism, and the guide tube is arranged in the wire feeding channel; the wire feeding wheel group adopts a double-wheel pressure structure for conveying wire; The straightening mechanism comprises a plurality of roller groups arranged orthogonally and staggeredly, and is used to allow the wire to enter the guide tube in a vertical state.

[0007] As a further implementation, a heat insulation layer is provided between the laser head and the wire feeding channel.

[0008] As a further implementation, the laser beam is a ring array beam.

[0009] As a further implementation, the nozzle has a set tilt angle, and the tilt angle is adapted to the annular array light beam.

[0010] As a further implementation method, the sensing module includes an optical fiber temperature sensor, a high-speed camera, a laser displacement sensor, an encoder and a photoelectric detector. The optical fiber temperature sensor is used to collect the molten pool temperature, the high-speed camera is used to obtain the molten pool morphology, the laser displacement sensor is used to obtain the deposition layer thickness, the encoder is used to collect the wire feeding speed, and the photoelectric detector is used to obtain the laser power.

[0011] In a second aspect, an embodiment of the present invention further provides a method for preparing complex aerospace components by using silk powder composite L-DED, using the system, comprising: Divide large continuous areas, transition areas and local detail areas; For large continuous areas, wire deposition is used. When the first switching condition is met, it is switched to wire-powder composite deposition in the transition area; when the second switching condition is met, it is switched to powder deposition in the local detail area. Among them, the first switching condition is that the geometric characteristics of the component reach the set threshold; the second switching condition is any one of the deposition thickness being lower than the set value, the molten pool morphology or the temperature being abnormal.

[0012] As a further implementation method, during the deposition process, a layered deposition strategy is adopted to obtain the molten pool temperature, molten pool morphology, deposition layer thickness, wire feeding speed and laser power in real time, and calculate the deviation value between the current deposition layer and the design parameters; the corresponding parameters are automatically adjusted according to the deviation value so that the next deposition layer compensates for the deviation of the previous deposition layer.

[0013] As a further implementation, silk powder composite processing is used for the transition area: In the initial stage, wire deposition is used to construct the base layer, and then powder material is gradually introduced and automatically adjusted according to the set silk-powder ratio; while increasing the powder material ratio, the wire feeding speed is reduced.

[0014] As a further implementation method, the process parameters and silk powder ratio curve are pre-established; During the deposition process in the transition zone, the molten pool state and deposition layer thickness are acquired in real time to dynamically match the silk powder mixing ratio with the laser parameters.

[0015] The beneficial effects of the present invention are as follows: (1) The present invention comprises a wire feeding module, a powder feeding module, a laser head, a sensor module, etc., forming a modular design, which is convenient for replacing a single module; the laser-wire-powder coaxial "sandwich structure" is adopted, which can realize the rapid switching or combined use of wire and powder processing, and ensure the accuracy and precision of wire processing and powder processing.

[0016] (2) The sensing module of the present invention comprises an optical fiber temperature sensor, a high-speed camera, a laser displacement sensor, an encoder and a photoelectric detector. The optical fiber temperature sensor is used to collect the temperature of the molten pool. The high-speed camera is used to obtain the molten pool morphology. The laser displacement sensor is used to obtain the thickness of the deposited layer. The encoder is used to collect the wire feeding speed. The photoelectric detector is used to obtain the laser power. The sensing module transmits the acquired data to the central controller. The central controller controls and adjusts the laser frequency, scanning speed, feeding speed and other parameters to form a dynamic closed control to ensure that self-correction is always performed during the deposition process, so that the final component achieves consistency and stability in terms of geometric size, density and microstructure.

[0017] (3) The present invention first uses wire deposition technology to quickly construct the main structure of the component in large continuous areas, ensuring that the main load-bearing part has sufficient volume and strength; a silk-powder composite deposition process is used in the transition area to achieve a gradient transition of material composition and microstructure, ensuring that the component performance transitions smoothly from wear resistance to high toughness; for local detail areas, powder deposition technology is used for fine filling and strengthening, ensuring that the detail size and surface quality meet strict requirements; through the combined effects of wire deposition, silk-powder composite deposition, and powder deposition, the rapid prototyping of the main structure is guaranteed, and performance gradient regulation can be achieved through the transition area. Finally, high-precision processing is achieved for local details, thereby improving the overall processing accuracy and efficiency of the component. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] Figure 1 is a schematic structural diagram of a silk powder composite system according to one or more embodiments of the present invention; Figure 2 is a schematic diagram of the coaxial arrangement of laser, silk and powder according to one or more embodiments of the present invention; Figure 3 is a schematic diagram of wire deposition according to one or more embodiments of the present invention; Figure 4 is a schematic diagram of powder material deposition according to one or more embodiments of the present invention; Figure 5 is a silk powder compounding process flow chart according to one or more embodiments of the present invention.

[0020] Among them, 1-laser beam, 2-powder, 3-shielding gas, 4-nozzle, 5-laser head, 6-wire feeding wheel group, 7-wire, 8-guide tube, 9-carrier gas, 200-substrate, 210-powder recovery device, 211-deposition layer, 212-molten pool, 220-carrier gas source, 230-air pressure valve, 240-vibrating powder feeder, 250-connector, 260-wire reel bracket, 270-wire feeding module, 280-water cooling box, 290-laser heat source, 300-shielding gas source, 310-sensing module, 320-high-speed camera, 330-central controller. DETAILED DESCRIPTION

[0021] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0022] Embodiment 1: This embodiment provides a silk powder composite L-DED system for preparing complex aerospace components, such as Figure 1 and Figure 2 As shown, it mainly includes a laser head 5, a wire feeding module 270, a powder feeding module, a sensor module 310 and a central controller 330. The laser head 5 is used to emit a laser beam 1, the wire feeding module 270 is used to transport the wire material 7, and the powder feeding module is used to transport the powder material 2. In this embodiment, a laser-wire-powder coaxial arrangement structure is adopted.

[0023] The laser head 5 is connected to the laser heat source 290, and the laser heat source 290 is connected to the water cooling box 280; in this embodiment, the laser beam 1 emitted by the laser head 5 is a ring array beam; the multimode fiber optic splitting technology is adopted, and the characteristics of the multimode fiber are utilized to couple a single laser beam into the multimode fiber through a fiber coupler, and then divided into multiple output ends, and the single laser beam is split into 8 groups of sub-beams according to the ring array, and focused into a ring spot with a diameter of 0.5~1.5mm through an aspherical lens. The ring laser supports independent power adjustment (each 30° sector area is controlled separately) through an acousto-optic modulator to meet the needs of the asymmetric molten pool 212 (such as the difference between the leading edge and the trailing edge of the turbine blade).

[0024] The wire feeding module 270 includes a wire feeding wheel set 6, a guide tube 8 and a straightening mechanism (not shown in the figure), wherein the guide tube 8 is arranged in the wire feeding channel, and the wire feeding channel is arranged inside the laser head 5, and the laser head 5 and the wire feeding channel are coaxially arranged. The straightening mechanism is used to correct the curvature of the wire 7 to ensure that the wire 7 is fed into the molten pool 212 in a straight line after passing through the guide tube 8. A heat insulation layer is arranged between the laser head 5 and the wire feeding channel, and the heat insulation layer adopts a microporous ceramic sheet to prevent heat back conduction from causing pre-melting of the wire 7.

[0025] Furthermore, the wire feeding wheel group 6 adopts a double-wheel pressure structure, including a driving wheel and a driven wheel. The driving wheel is connected to a servo motor, and the servo motor drives the driving wheel to rotate, and the driving wheel drives the driven wheel to rotate, providing power for the wire 7 to move forward.

[0026] The driving wheel and the driven wheel of this embodiment are detachably mounted, and wheel pairs of different diameters can be replaced to adapt to wires 7 of different wire diameters; the driving wheel and the driven wheel are made of hard alloy (such as WC-Co), which is wear-resistant and deformation-resistant; the surfaces of the driving wheel and the driven wheel are provided with anti-slip grooves.

[0027] like Figure 2 and Figure 3 As shown, the axial direction of the guide tube 8 is arranged along the vertical direction and is coaxially arranged with the laser head 5. The guide tube 8 plays a guiding role in the transmission of the wire 7. The straightening mechanism is arranged at the input end of the guide tube 8, which includes a plurality of roller groups arranged orthogonally and staggered. The material of the guide tube 8 is alumina ceramic, which is resistant to high temperature and insulated; the inner diameter of the guide tube 8 should be 1.2 to 1.5 times the diameter of the wire to prevent excessive friction resistance or shaking of the wire 7.

[0028] In this embodiment, there are three groups of rollers, each group of rollers includes two ceramic rollers. The first group of rollers is arranged at the output end of the wire feeding roller group, and is used to apply vertical pressure to the wire 7 to correct the longitudinal bending moment of the wire 7 (such as wave-shaped deformation). The two ceramic rollers are arranged in an upper and lower position, and the wire 7 passes through the two ceramic rollers in a horizontal direction; the spacing between the two ceramic rollers is adjustable, and the spacing between the two is adapted to the wire diameter ±0.1mm. The second group of rollers consists of two left and right ceramic rollers, which are used to apply horizontal pressure to correct the lateral bending of the wire 7 (such as serpentine twisting). The third group of rollers consists of two ceramic rollers arranged at a 45° angle, and the center lines of the two ceramic rollers are 45° to the horizontal direction. The two form an "eight-shaped" clamp, which is used to apply composite directional pressure, eliminate residual torsional stress, and ensure that the straightness of the wire 7 is <0.1mm / m.

[0029] like Figure 1 As shown, the wire feeding module 270 also includes a wire reel support 260, and the wire 7 is wound on the wire reel support 260; in order to prevent the wire 7 from being oxidized, the wire reel support 260 is arranged in a wire reel bin, and the wire reel bin has a built-in argon gas circulation system. During the feeding process of the wire 7, the tension sensor detects the wire feeding resistance to prevent wire breakage or material blockage; if the tension exceeds the set threshold, the speed is automatically reduced or the machine is stopped to alarm.

[0030] The powder feeding module includes a nozzle 4, such as Figure 2 and Figure 4 As shown, the nozzle 4 has a built-in powder delivery channel, which is arranged outside the laser head 5, and the powder material 2 is transported with the carrier gas 9; wherein the carrier gas 9 is an inert gas. Figure 1 As shown, the powder feeding module includes a vibrating powder feeder 240 and a carrier gas source 220 in addition to the nozzle 4. The carrier gas source 220 is connected to the vibrating powder feeder 240 through a pipeline, and the pipeline is equipped with an air pressure valve 230. The vibrating powder feeder 240 is connected to the powder supply bin. The vibrating powder feeder 240 uses a piezoelectric ceramic vibrating plate, and its vibration frequency is adjustable to prevent powder bridging.

[0031] In order to realize the recovery of the powder material 2, a powder material recovery device 210 is provided, and the powder material recovery device 210 and the vibrating powder feeder 240 are both connected to a connector 250, and connected to the nozzle 4 through the connector 250. The connector 250 is a four-way connector.

[0032] The inclination angle of nozzle 4 matches the annular laser beam, and its inclination angle range is 15°~25°. CFD simulation verifies that the convergence point of powder material 2 coincides with the position of molten pool 212. A protective gas 3 air curtain is added to the front end of nozzle 4. The protective gas 3 is input from the protective gas channel outside the powder feeding channel. The protective gas channel is connected to the protective gas source 300 through a pipeline, and a pressure valve 230 is installed on the pipeline. Argon is used for protective gas 3 to isolate splashes from the molten pool 212 and avoid contaminating the powder feeding channel. Nozzle 4 is replaceable, for example, a coaxial annular nozzle, a narrow slit nozzle or a wide-mouth nozzle; the material is selected from silicon carbide.

[0033] The sensing module 310 is used to obtain the key parameters of the molten pool 212, wire feeding and laser in real time. The key parameters include the temperature of the molten pool 212, the morphology of the molten pool 212, the thickness of the deposited layer 211, the wire feeding speed and the laser power. Therefore, the sensing module 310 includes an optical fiber temperature sensor, a high-speed camera 320, a laser displacement sensor, an encoder and a photoelectric detector. The optical fiber temperature sensor is used to collect the temperature of the molten pool 212, the high-speed camera 320 is used to obtain the morphology of the molten pool 212, the laser displacement sensor is used to obtain the thickness of the deposited layer 211, the encoder is used to collect the wire feeding speed, and the photoelectric detector is used to obtain the laser power.

[0034] For large continuous areas of complex aerospace components, wire feeding module 270 is used for processing, such as Figure 3 As shown, the laser beam 1 is distributed in a ring shape outside the wire 7. Through the action of the laser beam 1, a deposition layer 211 is formed on the surface of the substrate 200. For the local detail area, a powder feeding module is used for processing, such as Figure 4 As shown, the powder material 2 forms a deposition layer 211 under the action of the laser beam 1. For the transition area, the wire feeding module 270 and the powder feeding module work together to perform wire-powder composite deposition to ensure the smoothness of component processing.

[0035] This embodiment includes a wire feeding module 270, a powder feeding module, a laser head 5, a sensor module 310, etc., forming a modular design, which is convenient for replacing a single module; each module has an independent control unit, and can coordinate work through a central controller. The laser-silk-powder coaxial "sandwich structure" can achieve rapid switching of wire and powder processing or a composite effect of wire and powder, ensuring the accuracy and precision of wire material processing and powder material processing, and at the same time, the wire and powder processing will not affect each other.

[0036] Embodiment 2: This embodiment provides a method for preparing complex aerospace components using silk powder composite L-DED, using the system described in Example 1, such as Figure 5 As shown, the following steps are included: Step S1: Equipment preparation and pre-processing.

[0037] First, the system described in Example 1 is fully calibrated to ensure stable output and precise focusing of the laser head. At the same time, the wire feeding module and the wire feeding module are checked and adjusted to ensure that the two materials can be stably and continuously fed into the predetermined position during the deposition process.

[0038] The workpiece base is pretreated by chemical cleaning or ultrasonic cleaning to thoroughly remove surface oil, oxides and other impurities; then preheating is performed, and the preheating temperature is determined according to the workpiece material to eliminate the thermal stress caused by the temperature difference and prevent cracks or interlayer shedding during deposition.

[0039] Step S2: process planning and design optimization.

[0040] First, use 3D modeling software (such as CATIA, SolidWorks, etc.) to analyze the CAD model of the component and extract key geometric features, including curvature, wall thickness, plane area and complex surface information, and evaluate the curvature changes on the component surface, identify high curvature areas (such as sharp corners, complex surfaces) and low curvature areas (such as planes and cylindrical surfaces). High curvature areas usually require more refined processing; then determine the wall thickness of each part of the component, identify thin-walled areas and thick-walled areas, and detect holes, notches, ribs and other features in the component; finally, based on the extracted geometric features, divide the component into regions to match different additive manufacturing strategies.

[0041] Large continuous areas usually have lower curvature changes and larger areas, and are suitable for wire rapid deposition technology to improve manufacturing efficiency; local detail areas include high curvature areas, thin-walled structures, inner cavities and complex features, which require high precision and good surface quality, and are suitable for powder deposition technology to achieve fine processing. The transition area is located between the large continuous area and the local detail area, and its division is based on significant changes in geometric features. For example, when the local curvature suddenly rises from less than 5° / mm to more than 8° / mm, it can be predefined as a transition area; through silk-powder composite processing, a gradient transition of material composition and microstructure can be achieved in these areas.

[0042] Furthermore, the surface curvature of the component can be obtained by using the built-in geometric analysis tools in CAD. The surface can be discretized and then the principal curvature or mean curvature can be calculated at each point.

[0043] First, the continuous surface of the component is divided into many small grid units, and each grid node represents the geometric information of the local area. Then, for each grid node, the principal curvature k1 and k2 of the point are calculated using a discrete curvature calculation method (such as the change of the normal vector of the neighborhood point or the least squares fitting method), or the average curvature is directly calculated: (1) According to the design requirements, two thresholds are pre-set: a low threshold (5° / mm) indicates an area with lower curvature; a high threshold (8° / mm) indicates an area with higher curvature. When the curvature values ​​of some nodes in adjacent grid areas suddenly rise rapidly from below the low threshold to above the high threshold, this continuous, local curvature jump is identified as a signal of obvious surface change, thereby determining that the area needs to enter the transition mode.

[0044] Step S3: deposition process.

[0045] First, wire deposition is carried out in a large continuous area. When the transition area switching condition (the first switching condition) is met, it is switched to wire-powder composite processing, that is, processing is carried out according to the preset wire feeding and powder feeding ratio; when the fine filling mode switching condition (the second switching condition) is met, the wire feeding is stopped and only powder feeding is carried out; among which, the first switching condition is that the geometric feature reaches the set threshold, and the second switching condition meets any one of the following conditions: the deposition thickness is lower than the set value, the molten pool morphology or the temperature is abnormal.

[0046] Specifically, the wire deposition process for a large continuous area is: Taking advantage of the continuous wire feeding, high-efficiency deposition is used in the main area of ​​the component to quickly build a large-area, load-bearing main structure. The central controller coordinates the wire feeding module and the powder feeding module. At this stage, only the wire feeding module is started. At the same time, the fiber optic temperature sensor, high-speed camera, laser displacement sensor, encoder, and photoelectric detector are used to obtain the molten pool temperature, molten pool morphology, deposition layer thickness, wire feeding speed and laser power in real time, and feedback to the central controller. The central controller analyzes the collected data in real time to determine whether the current process status meets the preset area type standard. According to the analysis results, the central controller sends instructions to the wire feeding module controller to adjust the wire feeding speed and the power output of the laser head to ensure the stability of the molten pool and good metallurgical bonding between layers, so as to quickly build a main deposition layer with stable structure and reliable quality.

[0047] In order to ensure the stability of the molten pool temperature during the rapid deposition of the main structure, the energy balance formula is used: (2) In formula (2), Q is the laser input energy, m is the mass of the melted material in the molten pool, c is the specific heat capacity of the material, and ΔT is the temperature change. At the same time, in order to match the wire feeding speed with the laser scanning, the deposition rate R can be expressed by the following formula: (3) In formula (3), is the volume flow rate of the material fed, and A is the cross-sectional area of ​​the molten pool.

[0048] Furthermore, the silk powder composite deposition process in the transition region is: During the processing process, when the deposition path enters the preset transition area boundary, the central controller automatically switches the mode and gradually adjusts the material ratio according to the preset silk powder mixing gradient curve to achieve a smooth transition of material composition and microstructure, ensuring the performance gradient from wear resistance to high toughness.

[0049] In the initial stage of this area, wire deposition is mainly used to construct the base layer, and then powder material is gradually introduced. The central controller automatically adjusts the ratio according to the preset ratio, gradually increases the proportion of powder material, and reduces the wire feeding speed at the same time to achieve seamless mixing of the two materials during the deposition process.

[0050] The silk powder ratio function in the preset transition area is calculated along the length of the area. x (0≤ x ≤L), set the wire ratio: (4) In formula (4), the starting end f0 (e.g. 80%) represents the main use of wire, while the ending end f end (e.g. 20%) means that the powder material is dominant, and the powder material ratio is 1−f silk ( x ).

[0051] Furthermore, the powder deposition process in the local refinement area is as follows: The central controller collects data in real time through various sensors to monitor the deposition status of local areas (such as thin walls, inner cavities or complex curved surfaces). When the laser displacement sensor, high-speed camera and fiber optic temperature sensor detect that the deposition layer thickness is low, the molten pool morphology or temperature is abnormal, it indicates that the area requires higher-precision deposition control, and the system automatically determines that the area enters the fine filling mode.

[0052] For example: the designed deposition layer thickness is 1.0mm. When the actual measured thickness is lower than 0.8mm (i.e. lower than 80% of the target thickness), the deposition layer thickness is considered to be low. The molten pool is ideally elliptical, and its aspect ratio should be maintained between 1.2 and 1.5mm. If the actual measured aspect ratio exceeds this range or the molten pool area decreases by more than 20%, the molten pool morphology is considered to be abnormal. In addition, for temperature control, if the molten pool temperature is lower than 90% of the target temperature (for example, lower than 1530°C when the target temperature is 1700°C), the temperature is considered to be abnormal.

[0053] The central controller sends control instructions to each submodule through the CAN communication protocol: pause the wire feeding module, start the powder feeding module, and at the same time, adjust the laser focus and scanning strategy to adapt to the powder deposition. In the powder mode, the powder feeding module sprays the powder evenly to the predetermined area through the nozzle and carrier gas. The central controller continuously monitors the molten pool temperature and deposition quality, and uses the PID closed-loop control algorithm to adjust the laser power and powder feeding speed in real time to ensure the uniformity of powder deposition and the strengthening effect.

[0054] The PID closed-loop control algorithm is as follows: (5) In formula (5), u (t) is the control output (e.g., laser power adjustment or wire feed speed adjustment); e(t)=r(t)−y(t), which represents the error between the set value r(t) and the actual measured value y(t); e(τ) is an integral variable used to represent the error of τ at any time in the time interval [0, t]; K P Represents the proportionality coefficient, K I Indicates the integral coefficient, K D represents the differential coefficient.

[0055] In order to achieve online closed-loop control after each layer is deposited, the central controller adjusts the laser power in real time according to sensor data (such as melt pool temperature), expressed as follows: (6) In formula (6), T set is the target temperature, T measured is the actual measured molten pool temperature, k is the control coefficient, and ΔP is the change in laser power that needs to be adjusted.

[0056] In addition, in order to prevent false triggering, the system usually does not rely solely on a single measurement value, but adopts a mechanism of continuous detection or multiple confirmations in a short period of time to ensure that the abnormal state is real and persistent. Specifically, the central controller continuously collects sensor data within a predetermined time window (for example, 1 second or multiple sampling cycles), such as laser displacement sensors, molten pool morphology captured by high-speed cameras, and temperature data of optical fiber temperature sensors. The system first pre-processes these data, such as using moving average or median filtering to smooth short-term noise, and then compares the processed data with the preset threshold; only when the deposition layer thickness is detected to be lower than the target value, the molten pool morphology is abnormal, or the temperature is low for multiple consecutive times (for example, 3 consecutive times or more), the system will determine that there is a continuous abnormality in the area, thereby triggering the fine filling mode. Through this mechanism of continuous detection and multiple confirmations, false triggering caused by instantaneous sensor errors or noise can be effectively avoided, ensuring that the control strategy is switched only when the abnormal state is stable, thereby improving the reliability of the overall processing quality.

[0057] S4: Post-processing and quality inspection.

[0058] After deposition, the components will first undergo necessary heat treatment, such as annealing or stress relief, to improve their microstructure, eliminate residual stress and improve overall mechanical properties. Subsequently, a series of mechanical property tests (including fatigue, tensile, high temperature resistance and other tests) and non-destructive testing (such as ultrasonic, X-ray and magnetic particle testing) will be conducted to comprehensively evaluate the structural integrity, density and internal and external defects of the components to ensure that they meet the strict standards for aerospace applications.

[0059] It should be noted that in this embodiment, a layered deposition strategy is adopted throughout the deposition process. The thickness, density and surface quality of each layer directly affect the deposition effect of the next layer. After each layer is deposited, the material is rapidly solidified under the action of laser energy to form a stable deposition layer, providing a solid base for subsequent layers. The central controller receives data from each sensor in real time, analyzes key indicators such as temperature, layer thickness, and geometric deviation of each layer of deposition, and when it detects that the current layer deviates from the design parameters (for example, the deposition layer is too thin, the local temperature is too high, or the deposition morphology is uneven), the central controller will automatically calculate the error value and decide whether it is necessary to adjust the process parameters of the next layer.

[0060] The central controller automatically adjusts parameters such as laser power, scanning speed, and feeding speed based on the PID control strategy to ensure that the next layer of deposition can compensate for the deviation of the previous layer. For example, if the measured thickness of the deposited layer is slightly lower than expected, the system will appropriately reduce the wire feeding speed or adjust the laser power to improve the material deposition efficiency. Through timely feedback and adjustment after each layer of deposition, the deposition process of the entire component is always maintained in the best state to ensure that each layer meets the design requirements. In addition, real-time data and feedback form a dynamic closed loop to ensure that self-correction is always performed during the deposition process, so that the final component achieves consistency and stability in geometric size, density and microstructure.

[0061] In this embodiment, for large continuous areas, the main structure of the component is quickly constructed by wire deposition technology to ensure that the main load-bearing part has sufficient volume and strength; at the junction of the main structure and the local detail area (transition area), the silk powder composite deposition process is used to achieve a gradient transition of material composition and microstructure, ensuring that the component performance transitions smoothly from wear resistance to high toughness; for local areas that require high-precision processing such as thin walls, inner cavities, and complex curved surfaces, powder deposition technology is used for fine filling and strengthening to ensure that the detailed dimensions and surface quality meet strict requirements. It not only ensures the rapid prototyping of the main structure, but also realizes performance gradient regulation through the transition area, and finally realizes high-precision processing for local details, thereby improving the processing accuracy and efficiency of the component as a whole.

[0062] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A silk powder composite L-DED system for preparing complex aerospace components, characterized in that: include: A wire feeding module, a laser head and a nozzle are coaxially arranged, wherein the laser head is used to emit a laser beam; the nozzle has a built-in powder feeding channel, and the powder feeding channel is used to transport powder material provided by the powder feeding module; The sensing module is used to obtain the key parameters of the molten pool, wire feeding and laser in real time, and transmit the key parameters to the central controller, which is used to regulate the operation of the wire feeding module and / or the powder feeding module.

2. The silk powder composite L-DED system for preparing complex aerospace components according to claim 1, characterized in that: The wire feeding module includes a wire feeding wheel group, a guide tube and a straightening mechanism, wherein the guide tube is arranged in the wire feeding channel; the wire feeding wheel group adopts a double-wheel pressure structure for conveying wire; The straightening mechanism comprises a plurality of roller groups arranged orthogonally and staggeredly, and is used to allow the wire to enter the guide tube in a vertical state.

3. The silk powder composite L-DED system for preparing complex aerospace components according to claim 2, characterized in that: A heat insulation layer is provided between the laser head and the wire feeding channel.

4. The silk powder composite L-DED system for preparing complex aerospace components according to claim 1, characterized in that: The laser beam is a ring array beam.

5. The silk powder composite L-DED system for preparing complex aerospace components according to claim 4, characterized in that: The nozzle has a set tilt angle, and the tilt angle is adapted to the annular array light beam.

6. The silk powder composite L-DED system for preparing complex aerospace components according to claim 1, characterized in that: The sensing module includes an optical fiber temperature sensor, a high-speed camera, a laser displacement sensor, an encoder and a photoelectric detector. The optical fiber temperature sensor is used to collect the molten pool temperature, the high-speed camera is used to obtain the molten pool morphology, the laser displacement sensor is used to obtain the deposition layer thickness, the encoder is used to collect the wire feeding speed, and the photoelectric detector is used to obtain the laser power.

7. A method for preparing complex aerospace components by using silk powder composite L-DED, characterized in that: A system as claimed in any one of claims 1 to 6, comprising: Divide large continuous areas, transition areas and local detail areas; For large continuous areas, wire deposition is used. When the first switching condition is met, it is switched to wire-powder composite deposition in the transition area; when the second switching condition is met, it is switched to powder deposition in the local detail area. Among them, the first switching condition is that the geometric characteristics of the component reach the set threshold; the second switching condition is any one of the deposition thickness being lower than the set value, the molten pool morphology or the temperature being abnormal.

8. The method for preparing complex aerospace components by using silk powder composite L-DED according to claim 7, characterized in that: During the deposition process, a layered deposition strategy is adopted to obtain the molten pool temperature, molten pool morphology, deposition layer thickness, wire feeding speed and laser power in real time, and calculate the deviation value between the current deposition layer and the design parameters; the corresponding parameters are automatically adjusted according to the deviation value so that the next deposition layer compensates for the deviation of the previous deposition layer.

9. The method for preparing complex aerospace components by using silk powder composite L-DED according to claim 7, characterized in that: For the transition area, silk powder composite processing is used: In the initial stage, wire deposition is used to construct the base layer, and then powder material is gradually introduced and automatically adjusted according to the set silk-powder ratio; while increasing the powder material ratio, the wire feeding speed is reduced.

10. The method for preparing complex aerospace components by using silk powder composite L-DED according to claim 9, characterized in that: Pre-set process parameters and silk powder ratio curve; During the deposition process in the transition zone, the molten pool state and the thickness of the deposited layer are obtained in real time to dynamically match the silk powder mixing ratio with the laser parameters.

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