An arc additive manufacturing method for a defect-controllable aviation composite blade mold

Abstract

The present application relates to the field of aero-engine blade additive manufacturing, in particular to an arc additive manufacturing method of a defect-controllable aero-composite blade mold, the core idea is to use 3D data model adaptive processing, online abnormal monitoring, dynamic adjustment compensation, integrated post-processing to form a reliable processing model and the most suitable additive printing path, to additively manufacture a complete and shaped mold blank through arc additive manufacturing and process through post-processing to obtain the final mold product. Thus, the defect compensation is targeted and timely in the manufacturing process, which can significantly improve the forming quality, greatly shorten the production cycle and improve the additive manufacturing efficiency. The arc additive manufacturing technology features that the material can be maximized, the raw material cost is significantly reduced. The processing process is controllable and traceable, the process reliability is enhanced, the dependence on personnel experience is reduced, and it is more suitable for industrial popularization and promotion.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing of aero-engine blades, specifically to an arc additive manufacturing method for aero-engine composite blade molds with controllable defects. Background Technology

[0002] The molds for composite blades of aero-engines exhibit complex geometric features such as hollowness, thin walls, large curvature, and irregular curved surfaces. Currently, the main manufacturing process is a subtractive manufacturing process that combines forging blanks and CNC milling. However, this process has inherent drawbacks such as low material utilization, long processing cycles, and difficulty in machining complex surfaces.

[0003] In recent years, with technological advancements, electric arc additive manufacturing (WAAM) technology has provided a new approach for near-net-shape forming of large components. However, when directly applied to aerospace molds with extremely high precision and internal quality requirements, it still faces severe challenges: 1. Difficulty in controlling molding precision This is mainly reflected in two aspects: First, during the process of layer-by-layer stacking of complex curved surfaces and thin-walled structures, uneven heat input and heat accumulation can easily lead to warping deformation and internal stress.

[0004] Secondly, the molten pool flows on the inclined surface, resulting in weld beads and surface ripples, making it difficult to meet the mold requirements in terms of dimensional accuracy and surface quality.

[0005] 2. Uncontrollable internal defects Traditional WAAM process parameters are fixed, lacking real-time perception and feedback control of key process variables such as molten pool state and interlayer temperature, which easily leads to defects such as porosity, lack of fusion, and interlayer cracks.

[0006] These defects are usually only discovered through non-destructive testing after the entire molding process is completed, leading to costly rework or even the complete scrapping of the part.

[0007] 3. Disconnected process chain, resulting in low efficiency. The lack of precise machining references for additively formed workpieces makes it difficult to connect subsequent processes such as stress-relief annealing, reference surface finding, and large-area precision machining, which seriously prolongs the overall manufacturing cycle.

[0008] Therefore, existing technologies lack a comprehensive technical solution that can systematically resolve the contradiction between "precision, quality, and efficiency" in the manufacturing of aerospace composite molds (WAAM). Summary of the Invention

[0009] The purpose of this invention is to provide an arc additive manufacturing method for aerospace composite blade molds with controllable defects, so as to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: an arc additive manufacturing method for aerospace composite blade molds with controllable defects, comprising the following steps: S1. Model adaptive processing, including adjusting the external structure, reconstructing the internal support, reinforcing key nodes, and retaining sufficient machining allowance on the outer surface; Determine the processing model for additive manufacturing; S2. Based on the processing model, the software automatically generates the printing path, implements additive manufacturing and online monitoring, detects defects in real time, makes dynamic adjustments, and achieves closed-loop control; Obtain a preform that is formed as a whole; S3. Integrated post-processing: Based on a defined unified benchmark, the stiffener structure is cut along a preset path on the blank, and the machining allowance of the outer surface is finished. Obtain the finished mold.

[0011] Preferably, adjusting the external structure in step S1 means adjusting the original complex structure into an approximate regular structure to optimize the continuous printing path in the simplest way. Leave machining allowance on the entire outer surface.

[0012] Preferably, in step S1, reconstructing the internal support refers to changing the solid support plate, which is difficult to print directly, into a stiffener structure that can be post-processed. Strengthening key points refers to setting positioning bosses at the pre-set connection points of the stiffeners to facilitate positioning.

[0013] Preferably, the equipment for arc additive manufacturing in step S2 needs to integrate a 3D vision sensing module, a molten pool monitoring module, and a temperature field analysis system, and execute them throughout the entire process.

[0014] Preferably, the objects of closed-loop control in step S2 include balancing heat output, suppressing heat accumulation, compensating for deposition channels, triggering preset process intervention anomalies, and controlling overall deformation.

[0015] Preferably, heat output is balanced and inconsistent layer heights are reduced by using an alternating printing strategy between layers and different welding speeds in different areas; Adjusting core process parameters to increase deposition rate and suppress heat accumulation; Collect key image information and promptly compensate for sediment channels in case of inner wall collapse risk; If a process abnormality is detected, an alarm will be recorded, triggering a preset composite process for intervention. The process support block is printed synchronously in the internal cavity, and then stress-relief annealing is performed to prevent deformation.

[0016] Preferably, the core parameter adjustments include controlling the wire feeding speed at 5-12 m / min and the interlayer waiting time at 120-300 s.

[0017] Preferably, the key image information acquired includes molten pool images, arc information, and workpiece morphology; When there is an inclined area on the inner wall that is greater than the set warning angle, the compensation deposition channel can provide effective support for the subsequent layers and prevent the spread of defects.

[0018] Preferably, process abnormalities include contact tip burnout, abnormal protective gas, and arc ignition failure; The pre-set composite process includes laser cleaning.

[0019] Preferably, the unified reference in step S3 refers to a pre-designed process reference boss on the additive body or a feature plane with a clear spacing determined by comparison through three-dimensional scanning. The close integration of post-processing with integrated additive manufacturing can effectively avoid misalignment, welding deformation, and potential weld quality issues.

[0020] Compared with the prior art, the beneficial effects of this invention are as follows: 1. Molding quality is significantly improved Through online monitoring and closed-loop control, real-time prevention and correction of typical defects such as porosity, lack of fusion, and collapse are achieved. Using the added process support blocks and stress-relief annealing of the entire workpiece effectively controls workpiece deformation and significantly improves the internal density and dimensional stability of the mold.

[0021] 2. Manufacturing efficiency has been greatly improved. The combined effects of optimizing the printing path, increasing the deposition rate, and using efficient post-processing methods such as waterjet cutting can shorten the overall manufacturing cycle by more than 30% compared to traditional forging and milling processes.

[0022] 3. Extremely high material utilization rate The near-net-shape forming process enables material utilization to reach over 90%, significantly reducing raw material costs and aligning with the concept of green manufacturing.

[0023] 4. High process reliability Fully digital process monitoring and data traceability transform process experience into reproducible and optimizable procedures and parameters, reducing reliance on individual operator experience and ensuring consistent batch production quality. Attached Figure Description

[0024] Figure 1 This is the overall process flow diagram of the present invention; Figure 2 This is a schematic diagram of the model preprocessing in this invention (showing the design of the ribs and bosses). Figure 3 This is a schematic diagram of the alternating printing path between layers in this invention; Figure 4 , Figure 5 and Figure 6 These are schematic diagrams illustrating the key stages of the manufacturing method in this invention. Detailed Implementation

[0025] Please see Figure 1-6 This invention discloses an arc additive manufacturing method for aerospace composite blade molds with controllable defects, such as... Figure 1 As shown, the process includes three core stages: adaptive model preprocessing, additive manufacturing process monitoring and defect compensation based on online monitoring, and integrated post-processing. First, the model and printing path are optimized, and then additive manufacturing is implemented. Post-processing can only begin after the main stage preliminary inspection is qualified; otherwise, it needs to be repaired before being sent to the post-processing production line. After post-processing, the workpieces must undergo quality inspection, and they can only be delivered after they are fully qualified. Workpieces that cannot be remedied or fail the inspection are scrapped, thus forming a complete closed-loop process.

[0026] like Figure 4 As shown, the first step is model adaptive preprocessing, which includes adjusting the external structure, reconstructing the internal support, reinforcing key nodes and facilitating positioning, retaining sufficient machining allowance on the outer surface, and determining the final machining model and printing path for additive manufacturing.

[0027] Model preprocessing is essentially for the rational and efficient construction of the mold model. First, the 3D model of the blade mold provided by the customer is imported into a dedicated CAM software for arc additive manufacturing, such as LungoPNT. Based on the imported model, open structures (such as the original complex open shell) are adjusted into closed rotating structures to simplify and optimize the continuous printing path. Secondly, such as... Figure 2 As shown, the support structure inside the mold, which is difficult to form directly, is reconstructed. The solid support plate is replaced with a rib structure that can be post-processed in step three. Cylindrical positioning bosses are added at the preset connection positions (usually the ends) of the rib structure to facilitate precise positioning and connection later. Finally, a uniform machining allowance of 2-8mm is applied to the overall outer surface of the mold, while the internal shape remains unchanged to ensure the dimensional accuracy after final machining and to provide material margin for machining in step three. The optimized machining model is then obtained.

[0028] like Figure 5 As shown, step two involves complete process control of additive manufacturing based on online monitoring. According to the processing model determined in step one, the software automatically generates the processing path, performs arc additive manufacturing, and monitors it online. Defects are detected in real time and dynamically adjusted to achieve closed-loop control. Finally, a preform is obtained.

[0029] It is executed on a smart WAAM that integrates a 3D vision sensing module, a molten pool monitoring module, and a temperature field analysis system, such as a smart WAAM device that integrates the Q-Ark quality ark monitoring system. The processed model is loaded into the software, such as... Figure 3 As shown, the system automatically generates the printing path after processing with an alternating layer strategy, and uses differentiated welding speeds for the inner and outer wall contours and the internal filling area to balance heat output and reduce layer height inconsistencies caused by interface changes. Simultaneously, core process parameters are adjusted to suppress heat accumulation. The specific parameters for the two nodes are set as follows: wire feed speed 5-12 m / min, preferably 9 m / min; inner and outer wall travel speed 8-15 mm / s; filling area travel speed 10-18 mm / s; and interlayer waiting time 120-300 s.

[0030] After printing begins, the arc additive manufacturing process is continuously monitored, with real-time acquisition of images of the molten pool, arc information, and workpiece morphology. When a risk of collapse due to gravity in an area with an inclined inner wall is detected, the system automatically triggers a compensation program, adding an extra deposition pass to the inner wall of that area to provide effective support for subsequent layers and prevent defect propagation. Specifically, when printing reaches an area in the middle of the mold where the inner wall inclination angle exceeds the set warning angle (set according to process requirements), the system detects a slight concavity trend on the surface of the formed layer using a 3D vision sensor. It then automatically calls the preset repair welding program, adding a weld pass with the same parameters along the inner wall trajectory of that layer, successfully repairing the collapse trend and ensuring the flatness of subsequent layers.

[0031] Simultaneously, the system monitors the entire printing process, alarming and recording process anomalies such as contact tip burnout, abnormal protective gas, and arc ignition failure. It can also trigger preset composite processes such as laser cleaning for intervention. For example, during the printing process, the system successfully issued a warning of minor contact tip blockage, which was resolved after a pause for cleaning, without causing any quality loss. To control overall deformation, process support blocks are simultaneously printed in the cavity inside the mold. Immediately after printing, the workpiece, along with the substrate, is sent to a heat treatment furnace for annealing: the temperature is raised to 500-800℃ at a rate of 50-150℃ / h, held for 1-3 hours, and then slowly cooled in the furnace to below 250-350℃ before being air-cooled, finally obtaining a fully formed blank.

[0032] like Figure 6 As shown, in step three, post-processing is performed on the blank prepared in step two. The post-processing process is closely integrated with additive manufacturing to form an integrated solution, ultimately obtaining the finished mold.

[0033] First, using pre-designed process reference bosses on the additive body, or feature planes with a defined spacing determined through 3D scanning comparison, as the reference surface for machining, can efficiently solve the problem of missing references in additive parts. Specifically, the annealed workpiece is separated from the substrate, and the workpiece is scanned using a 3D scanner. The point data is compared with the original design model. Based on the comparison results, a pair of parallel feature planes with a 60mm distance between the two ends of the workpiece can be selected as references. These are then precision milled on a five-axis CNC machine to produce a high-precision first reference plane. Then, using this reference plane as a positioning point, machining cutting technology is used to precisely cut the internal rib structure from the integrally formed blank along a preset path, following the rib contour lines in the digital model. This method completely avoids the alignment errors, welding deformation, and weld quality issues associated with the traditional "separate printing and subsequent welding" approach. Finally, using the machined reference plane as a reference, the outer contour is subjected to final CNC precision machining to remove the reserved machining allowance, resulting in an aerospace composite blade mold that fully meets the design dimensions and surface quality requirements.

[0034] In summary, this invention addresses the challenges of complex geometric features and demanding applications for composite material blade molds used in aero-engines, such as hollow, thin-walled, high-curvature, and irregularly shaped surfaces. These features lead to low material utilization, long processing cycles, difficulties in machining complex surfaces, and challenges in matching processing precision and internal quality requirements in arc additive manufacturing. By integrating adaptive model preprocessing, online monitoring and closed-loop feedback of multi-source information, and an integrated post-processing workflow, this invention achieves high-quality, high-efficiency, and high-reliability overall molding of the mold. It ensures that the mold's dimensional accuracy, internal density, and surface quality meet aerospace-grade standards, effectively solving the problems of difficult molding precision control, uncontrollable internal defects, disjointed process chains, and low efficiency. The invention optimizes and enhances molding quality, manufacturing efficiency, material utilization, and process reliability.

[0035] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An arc additive manufacturing method for aerospace composite blade molds with controllable defects, characterized in that, The steps are as follows: S1. Model adaptive processing, including adjusting the external structure, reconstructing the internal support, reinforcing key nodes, and retaining sufficient machining allowance on the outer surface; Determine the processing model for additive manufacturing; S2. Based on the processing model, the software automatically generates the printing path, implements additive manufacturing and online monitoring, detects defects in real time, makes dynamic adjustments, and achieves closed-loop control; Obtain a preform that is formed as a whole; S3. Integrated post-processing: Based on a defined unified benchmark, the stiffener structure is cut along a preset path on the blank, and the machining allowance of the outer surface is finished. Obtain the finished mold.

2. The arc additive manufacturing method for a defect-controllable aerospace composite blade mold according to claim 1, characterized in that, In step S1, adjusting the external structure means adjusting the original complex structure into an approximate regular structure in order to optimize the continuous printing path in the simplest way. Leave machining allowance on the entire outer surface.

3. The arc additive manufacturing method for a defect-controllable aerospace composite blade mold according to claim 1, characterized in that, In step S1, reconstructing the internal support refers to changing the solid support plate, which is difficult to print directly, into a stiffener structure that can be processed later. Strengthening key points refers to setting positioning bosses at the pre-set connection points of the stiffeners to facilitate positioning.

4. The arc additive manufacturing method for a defect-controllable aerospace composite blade mold according to claim 1, characterized in that, In step S2, the equipment for arc additive manufacturing needs to integrate a 3D vision sensing module, a molten pool monitoring module, and a temperature field analysis system, and execute these throughout the entire process.

5. The arc additive manufacturing method for a defect-controllable aerospace composite blade mold according to claim 1, characterized in that, The objects of closed-loop control in step S2 include balancing heat output, suppressing heat accumulation, compensating for deposition channels, triggering preset process intervention anomalies, and controlling overall deformation.

6. The arc additive manufacturing method for a defect-controllable aerospace composite blade mold according to claim 4, characterized in that, By employing an alternating layer printing strategy and varying welding speeds in different areas, heat output is balanced, reducing inconsistent layer heights. Adjusting core process parameters to increase deposition rate and suppress heat accumulation; Collect key image information and promptly compensate for sediment channels in case of inner wall collapse risk; If a process abnormality is detected, an alarm will be recorded, triggering a preset composite process for intervention. The process support block is printed synchronously in the internal cavity, and then stress-relief annealing is performed to prevent deformation.

7. The arc additive manufacturing method for a defect-controllable aerospace composite blade mold according to claim 6, characterized in that, The core parameter adjustments include controlling the wire feeding speed at 5-12 m / min and the interlayer waiting time at 120-300 s.

8. The arc additive manufacturing method for a defect-controllable aerospace composite blade mold according to claim 6, characterized in that, The key image information acquired includes molten pool images, arc information, and workpiece morphology; When there is an inclined area on the inner wall that is greater than the set warning angle, the compensation deposition channel can provide effective support for the subsequent layers and prevent the spread of defects.

9. The arc additive manufacturing method for a defect-controllable aerospace composite blade mold according to claim 6, characterized in that, Process abnormalities include contact tip burnout, abnormal protective gas, and arc ignition failure; The pre-set composite process includes laser cleaning.

10. The arc additive manufacturing method for a defect-controllable aerospace composite blade mold according to claim 1, characterized in that, In step S3, the unified reference refers to a pre-designed process reference boss on the additive body or a feature plane with a clear spacing determined by comparison through three-dimensional scanning. The close integration of post-processing with integrated additive manufacturing can effectively avoid misalignment, welding deformation, and potential weld quality issues.

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