Manufacturing method and mold of stator blade made of high-temperature-resistant composite material

Abstract

The invention discloses a manufacturing method of a high-temperature-resistant composite material stator blade and a mold thereof in the technical field of aero-engines. The manufacturing method comprises the following steps: S1, material pretreatment and mold preparation; s2, laying and pre-compaction are carried out; s3, carrying out vacuum mould pressing and curing molding; s4, carrying out edge covering treatment; and S5, detecting and post-processing. According to the method, the specially-made mold is arranged, the upper mold and the lower mold are buckled for pressing, the inclined pressing block provides side face pressing, multi-face pressing is carried out in cooperation with staged vacuumizing, uniform flowing and sufficient curing of resin are achieved, and the size stability and the mechanical property of the blade in the high-temperature environment are guaranteed; besides, in the edge covering treatment, a low-temperature curing high-temperature-resistant adhesive is used for bonding and edge covering, so that edge transition of the blade is smoother, the blade is almost free of deformation after edge covering, and meanwhile, through a series of treatment such as vacuum control, temperature management and quality detection, the manufactured stator blade has excellent internal compactness.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engines, and in particular to a manufacturing method of a high-temperature resistant composite material stator blade and a mold thereof. Background Art

[0002] Composite stator blades are key components of the hot-end of aircraft engines, and their molding quality directly impacts the engine's high-temperature performance and reliability. With the continuous improvement of thrust-to-weight ratios in new-generation aircraft engines, high-pressure compressor outlet temperatures have exceeded 650°C, placing even more stringent demands on the stator blades' temperature resistance, creep resistance, and dimensional stability. Currently, the industry primarily utilizes prepreg molding and RTM processes. However, due to limitations in material systems and process characteristics, these products exhibit systemic defects under high-temperature operating conditions.

[0003] In the prepreg molding process, there are three problems when multi-layer prepreg stacking is cured at high temperature: First, to meet the process viscosity requirements, the resin system usually adopts low molecular weight epoxy, whose glass transition temperature is generally lower than 280°C, causing the matrix to soften at high temperature; second, the difference in fluidity between the layers of prepreg during the molding process can easily form resin accumulation areas and dry spot defects. Micro-CT detection shows that the porosity is as high as 3% to 5%; third, during high-temperature curing, the volatile matter discharge channel is blocked by the densified resin on the surface, forming a micron-level closed-cell structure, which will become a source of crack initiation under thermal cycling loads.

[0004] Although the RTM process improves the uniformity of fiber distribution by impregnating the preform with liquid resin, there is a more complex process window contradiction: the balance between resin viscosity and curing rate requires the injection pressure to be precisely controlled within the range of 0.3-0.5MPa. In actual production, more than 62% of scrap is caused by incomplete impregnation; at the same time, the resin flash at the mold parting surface will undergo oxidation and carbonization at high temperature, forming a stress concentration point.

[0005] In summary, in order to solve the problems of internal molding quality of high-temperature resistant stator blades, high porosity and general surface quality in the process, and the inability of blades to meet high-temperature use conditions, we propose a manufacturing method and mold for high-temperature resistant composite material stator blades. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention provides a method for manufacturing a high-temperature resistant composite material stator blade and a mold thereof. The purpose of the present invention is achieved as follows: A method for manufacturing a high-temperature resistant composite material stator blade comprises the following steps: S1, material pretreatment and mold preparation: Gradual thawing of the material prepreg, precision inspection of the mold surface, and spraying of high-temperature resistant release agent; S2, Lamination and Pre-compaction: Laser projection is used to locate the layup paths for the blade base, blade back, and lugs, and then the layers are laid in sections, with prepreg filling in the triangular areas. S3, vacuum molding and curing: After the mold is assembled, pre-pressing is performed to check whether there is excess material. Pre-pressing is performed again until the requirements are met, and then pressurization curing is performed. After completion, the semi-finished blade product is demoulded and removed; S4, edge wrapping: Surface treatment of the leading and trailing edges of the blades, laying adhesive film and encapsulation, curing and bonding in an autoclave; S5, Inspection and Post-processing: Inspect the adhesion strength of the blade edge and protect the edge with paper tape. Perform final inspection and post-processing to form the finished blade.

[0007] Optionally, the specific process of step S1 is as follows: first, the prepreg is sealed in an insulation box and transferred to a constant temperature device, and then thawed by gradient heating; A two-stage process is used to clean the mold surface, preheat the mold, and finally apply the release agent in layers through a composite process.

[0008] Optionally, the gradient temperature thawing is specifically as follows: In the first stage, the prepreg material is sealed and transferred to a transition environment at 15°C, where it is left to rise in temperature. In the second stage, the prepreg is then transferred to a standard constant temperature and humidity environment to thaw; The two-stage process includes acetone cleaning and electrostatic dust removal treatment; The specific processing method of the composite process includes spraying the release agent and wiping with non-woven fabric, and the spraying of the release agent and wiping with non-woven fabric are performed alternately.

[0009] Optionally, the specific process of step S2 is: S21, importing the laser projection blanking pattern into the automatic blanking machine, and cutting the prepreg into paving sheets; S22, marking the ply sequence number on the edge of each paving sheet, and distinguishing paving sheets in different paving areas by using colored isolation films; S23, arranging the sheets in the order of plying and covering them with an isolation film for dust and moisture proofing; S24, placing the paving molds directly under the projectors, opening the corresponding projection files, and verifying the projection profiles; S25, positioning according to the projection contour, performing paving and bag making pre-drawing alternately according to the plying order until paving is completed; S26, closing and locking the upper mold and the lower mold, and placing them vertically; S27, cutting the paving sheet into carbon filaments with a width of 2 to 15 mm, and filling the triangular area until it is filled.

[0010] Optionally, the paving area includes: leaf basin paving, leaf back paving, and lug paving; The specific steps of performing the laying and bag making pre-extraction alternately in the laying order are as follows: When laying, the prepreg is laid in the order of layers. After the first layer of prepreg is laid, the bag is pre-pumped, and then pre-pumped every two layers until the laying is completed. The vacuuming time of each bag making pre-vacuuming is not less than 15 minutes.

[0011] Optionally, in step S3, the pre-pressing treatment is specifically: performing multi-surface pressurization treatment on the prepreg through a mold; The multi-faceted pressure includes the pressure of the upper and lower molds buckled together, and the side pressure applied by the oblique pressure block to the upper and lower molds through the side pressure blocks; The pressurized curing adopts staged vacuuming.

[0012] Optionally, a temperature measurement network and a vacuum press device are provided outside the mold, wherein the temperature measurement network includes a main control thermocouple located in the middle of the blade body; Auxiliary thermocouples, located at the blade tip, blade root and both sides of the lug; The temperature measurement network is doubly fixed by high-temperature silicone tape and metal clips.

[0013] Optionally, the process of step S4 is specifically as follows: S41, grinding and cleaning the edge area of ​​the semi-finished blade product; S41, applying film to the blade bonding area and performing bag making pre-pumping; S41, install the edge wrapping on the blade, tap it lightly to complete the assembly, and then wrap it tightly with a single-sided adhesive release cloth; S41, covering the blade product with vacuum auxiliary materials; S41, after the blade product is fixed in the autoclave, the vacuum bag auxiliary materials are removed and the overflowed glue is cleared.

[0014] Optionally, the vacuum bag auxiliary material includes a vacuum bag film, a breathable felt, and an isolation film. When the blade product is coated with the vacuum auxiliary material, adhesive tape, isolation film, breathable felt, and vacuum bag film are laid on the surface of the blade product in sequence; The final inspection includes: inspecting the leading edge of the blade product, the surface flatness and smoothness of the product, the debonding condition of the bonding interface, and whether there are edge burrs; The post-processing includes: cleaning the surface of the blade parts of the redundant materials, coding marking, and packaging with bubble pads.

[0015] A mold for a high-temperature resistant composite material stator blade, used in the above-mentioned method for manufacturing a high-temperature resistant composite material stator blade, includes a base plate, a fence is provided on the base plate, a compression molding area is formed between the base plate and the fence, an upper mold and a lower mold are provided in the fence, the upper mold and the lower mold are buckled together, a side mold assembly is provided in the fence, for applying pressure to the sides of the upper mold and the lower mold, the side mold assembly includes a side pressure block, a backhoe block and an inclined pressure block.

[0016] Compared with the existing technology, the present invention has the following advantages: by adopting a vacuum molding process, the molding quality and performance of high-temperature resistant composite stator blades are improved. Compared with the traditional prepreg laying / molding process and preform / RTM process, the technical problems of high internal porosity and poor surface quality of the product are solved; At the same time, through the interlocking pressure of the upper and lower molds, and the side pressure provided by the inclined pressure block, combined with staged vacuuming to achieve multi-sided pressure, uniform flow and full curing of the resin, the dimensional stability and mechanical properties of the blade in high-temperature environments are ensured, and the reliability verification level of the product is improved. In addition, fine grinding and protective technology are used in the edging process, and low-temperature curing and high-temperature resistant adhesives are used for bonding and edging, which makes the blade edge transition smoother, improves the surface quality, and there is almost no deformation of the blade after edging. At the same time, through a series of treatments such as vacuum control, temperature management and quality inspection, the stator blades have excellent internal density. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0018] Figure 1 It is a framework diagram of the manufacturing method of the high-temperature resistant composite material stator blade provided by the present invention.

[0019] Figure 2 This is a manufacturing flow chart of the semi-finished stator blade provided by the present invention.

[0020] Figure 3 This is a process flow chart of the stator blade edge binding and gluing process provided by the present invention.

[0021] Figure 4 It is a schematic diagram of the structure of the stator blade provided by the present invention.

[0022] Figure 5 It is an exploded view of the overall structure of the mold provided by the present invention.

[0023] Figure 6 It is a schematic diagram of the upper and lower molds and side pressure blocks of the stator blade mold provided by the present invention.

[0024] Figure 7 It is a schematic diagram of the stator blade mold provided by the present invention.

[0025] Figure 8 It is a schematic diagram of the nickel edging bonding of the stator blades provided by the present invention.

[0026] In the figure: 1. Base plate; 11. Enclosure; 2. Upper mold; 3. Lower mold; 4. Side mold assembly; 41. Side pressure block; 42. Backhoe block; 43. Oblique pressure block; 10. Hanging ear; 20. Glue groove; 30. Blade; 40. Edge wrapping. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] like Figures 1 to 7 A method for manufacturing a high-temperature resistant composite material stator blade is shown, comprising the following steps: S1, material pretreatment and mold preparation: Gradual thawing of the material prepreg, precision inspection of the mold surface, and spraying of high-temperature resistant release agent; S2, Lamination and Pre-compaction: Laser projection is used to locate the layup paths for the blade base, blade back, and lugs, and then the layers are laid in sections, with prepreg filling in the triangular areas. S3, vacuum molding and curing: After the mold is assembled, pre-pressing is performed to check whether there is excess material. Pre-pressing is performed again until the requirements are met, and then pressurization curing is performed. After completion, the semi-finished blade product is demoulded and removed; S4, edge wrapping: Surface treatment of the leading and trailing edges of the blades, laying adhesive film and encapsulation, curing and bonding in an autoclave; S5, Inspection and Post-processing: Inspect the adhesion strength of the blade edge and protect the edge with paper tape. Perform final inspection and post-processing to form the finished blade.

[0029] Furthermore, the vacuum molding process improves the molding quality and performance of high-temperature composite stator blades. Compared with the traditional prepreg layup / molding process and preform / RTM process, it solves the technical problems of high internal porosity and poor surface quality of the product. At the same time, through the interlocking pressure of the upper and lower molds, and the side pressure provided by the inclined pressure block, combined with staged vacuuming to achieve multi-sided pressure, uniform flow and full curing of the resin, the dimensional stability and mechanical properties of the blade in high-temperature environments are ensured, and the reliability verification level of the product is improved. In addition, fine grinding and protective technology are adopted in the edging process, and low-temperature curing and high-temperature resistant adhesives are used for bonding the edging, so that the blade edge transition is smoother, the surface quality is improved, and there is almost no deformation of the blade after edging. At the same time, through a series of treatments such as vacuum control, temperature management and quality inspection, the obtained stator blades have excellent internal density, which can better meet the long-term use requirements of aircraft engines under extremely high temperature conditions.

[0030] It should be noted that the stator blades and edging are both made of BMI / polyimide composite materials.

[0031] Specifically, the specific process of step S1 is that, first, the prepreg is sealed in an insulation box and transferred to a constant temperature device, and then the temperature is gradually increased to thaw. At the same time, a two-stage process is used to clean the mold surface and preheat the mold. Finally, the release agent is applied in layers through a composite process.

[0032] Furthermore, the molding quality of the composite material stator blades can be improved through the prepreg pretreatment and mold preparation process. First, the prepreg adopts a sealed heat preservation transfer and gradient temperature thawing process to avoid the performance degradation caused by moisture absorption and sudden temperature changes of the material. The composite process uses a layered coating method of the release agent to ensure the demoulding effect and avoid the uneven coating problem that may be caused by traditional single coating.

[0033] Specifically, in step S1, the gradient thawing is specifically as follows: In the first stage, the prepreg material is sealed and transferred to a transition environment at 15°C, where it is left to rise in temperature. In the second stage, the prepreg is then transferred to a standard constant temperature and humidity environment to thaw.

[0034] Furthermore, through segmented gradient thawing, sudden temperature changes are reduced, and the problem of material scrapping caused by surface condensation during the thawing process is completely avoided. First, the step-by-step heating ensures that the surface temperature of the material is always higher than the dew point temperature, physically blocking the condensation of water vapor; second, the slow heating ensures that the temperature inside and outside the prepreg is balanced, avoiding local differences in resin fluidity.

[0035] The two-stage process includes acetone cleaning and electrostatic dust removal.

[0036] Furthermore, first, an acetone solvent and a dust-free cloth are used for primary cleaning to thoroughly dissolve and remove oil stains and residual release agent on the mold surface; then, an electrostatic dust removal cloth is used for secondary cleaning to effectively remove tiny particles and fiber residues on the mold surface through electrostatic adsorption. On the one hand, acetone cleaning ensures basic cleanliness, while on the other hand, electrostatic dust removal can make up for the shortcomings of traditional cleaning in removing micron-level pollutants. Therefore, the two-stage process not only avoids coating defects caused by detergent residue, but also improves the cleanliness of the mold surface, allowing the subsequent release agent to form a more uniform and dense protective film, thereby improving the surface quality and demolding performance of composite parts.

[0037] The specific processing method of the composite process includes spraying the release agent and wiping with non-woven fabric, and the spraying of the release agent and wiping with non-woven fabric are performed alternately.

[0038] Furthermore, when spraying, the nozzle of the spray gun needs to be 20 to 30 cm away from the mold surface, spray evenly, maintain a stable moving speed, avoid local over-thickness of spraying, and let it stand for 2 minutes after spraying to allow the solvent to evaporate. When wiping with non-woven fabric, you need to use clean non-woven fabric to prevent the falling of fibers, or use microfiber cloth. During operation, gently wipe the non-woven fabric along the mold surface to remove the spray accumulation droplets or edge residues; It should be noted that when wiping, one-way wiping should be maintained to avoid back-and-forth friction. First, back-and-forth wiping will cause the excess release agent that has been wiped away to be brought back to the surface, forming an uneven coating; second, repeated friction of the non-woven fabric may cause trace fibers to fall off and contaminate the mold surface; third, one-way wiping can ensure the directional consistency of the coating, that is, one-way wiping makes the release agent molecules align in the same direction, thereby improving the demolding effect; fourth, one-way wiping can reduce the risk of surface scratches, especially for high-finish molds, back-and-forth friction may produce microscopic scratches.

[0039] Specifically, the specific process of step S2 is: S21, importing the laser projection blanking pattern into the automatic blanking machine, and cutting the prepreg into paving sheets; S22, marking the ply sequence number on the edge of each paving sheet, and distinguishing paving sheets in different paving areas by using colored isolation films; S23, arranging the sheets in the order of plying and covering them with an isolation film for dust and moisture proofing; S24, placing the paving molds directly under the projectors, opening the corresponding projection files, and verifying the projection profiles; S25, positioning according to the projection contour, performing paving and bag making pre-drawing alternately according to the plying order until paving is completed; S26, closing and locking the upper mold and the lower mold, and placing them vertically; S27, cutting the paving sheet into carbon filaments with a width of 2 to 15 mm, and filling the triangular area until it is filled.

[0040] Furthermore, firstly, dynamic calibration through laser projection can reduce interlayer bubbles, ensure accurate fiber positioning, and avoid wrinkles or misalignment; secondly, directional cutting of carbon filaments is used to optimize local mechanical properties, increase the filling density of the triangular area, and reduce curing defects; in addition, the edge of the sheet is marked with layer numbers and colored isolation film is used for zoning management to reduce the risk of mixing, and infrared thermal imagers can quickly detect interlayer defects to reduce rework.

[0041] Specifically, the paving areas include: leaf basin paving, leaf back paving, and ear paving; Furthermore, the blade basin refers to the side of the blade that bears the airflow pressure, that is, the concave surface. It is mainly affected by aerodynamic pressure when the engine is working. The paving of this area must ensure good aerodynamic shape and structural strength to reduce airflow separation and stress concentration. At the same time, the surface must be smooth to reduce flow resistance.

[0042] The back of the blade refers to the suction side of the blade, i.e. the convex surface, which is prone to generate high tensile stress under aerodynamic loads. The laying of this area needs to focus on optimizing the fiber arrangement direction to improve tensile strength and fatigue resistance. At the same time, the resin content needs to be controlled to avoid surface defects. The lug is the load-bearing structure that connects the blade to the disc or casing, usually located at the blade root or specific installation position. The paving in this area needs to adopt a reinforced design to ensure sufficient mechanical strength and impact resistance to meet the reliability requirements of assembly and long-term service.

[0043] Specifically, the alternating execution of laying and bag making and pre-drawing in the laying order is as follows: When laying, the prepreg is laid in the order of layers. After the first layer of prepreg is laid, the bag is pre-pumped, and then pre-pumped every two layers until the laying is completed. The vacuuming time of each bag making pre-vacuuming is not less than 15 minutes.

[0044] Furthermore, a continuous and stable negative pressure environment is formed by vacuuming to ensure that the gas is quickly and completely discharged, so that the bag reaches a sufficient vacuum degree and the porosity is controlled. At the same time, the continuous vacuuming operation is simple and efficient, and a single completion does not require interruption, which not only ensures the consistency of product quality but also improves production efficiency.

[0045] Specifically, in step S3, the pre-pressing treatment is specifically: performing multi-surface pressurization treatment on the prepreg through a mold; The multi-faceted pressure includes the pressure of the upper die and the lower die being buckled together, and the side pressure applied by the oblique pressure block to the upper die and the lower die through the side pressure block.

[0046] Furthermore, traditional molds and presses only apply pressure to the upper and lower surfaces of the mold. However, based on the special structure of the mold provided in this application, the inclined pressure blocks of the mold can be used to apply pressure to the sides of the lugs, thereby achieving multi-sided pressure treatment.

[0047] The pressurized curing adopts staged vacuuming.

[0048] It should be noted that since the resin used in traditional processes is not resistant to high temperatures, this type of resin has excellent fluidity and does not require pressurization. However, in order to enhance the high-temperature resistance of the blade, the prepreg provided in the present invention adds a high-temperature resistant resin. Due to its high molecular structure rigidity and high melt viscosity, the fluidity is significantly reduced, resulting in the fluidity of the resin with high-temperature resistance becoming worse. Therefore, the shape of the blade cannot be guaranteed by only using the mechanical locking method in the existing technology. Therefore, it is necessary to add an inclined pressure block to the conventional mold to complete the side pressurization, compensate for the resin flow resistance, and ensure the density of complex areas such as the blade edge and tenon.

[0049] Furthermore, during the curing process, the vacuum press performs a staged vacuuming mode. Due to the viscosity of the BMI resin, the reaction principle characteristics and the structural characteristics of the molding die, the viscosity of the resin changes in a W shape as the temperature increases, that is, there are two low viscosity points, namely: 100℃ and 160℃; At 100°C, the viscosity is low, but it can fully impregnate the fiber, while reacting and releasing small gas molecules. At the same time, it is not advisable to vacuum for too long. Overflow grooves are designed on both sides of the blade body to prevent the resin from being completely sucked away, which would affect the resin content of the product and cause excessive porosity. Therefore, after pumping 10-15mmn, the press vacuum mode should be immediately turned off. After the resin reaches 160℃ and reaches its low viscosity point, pressurize it and start the full vacuum mode to release a small amount of gas. At this time, the viscosity is relatively high and the glue will not be sucked away, which will not affect the resin content of the product.

[0050] Specifically, a temperature measuring hole is provided on the outside of the mold, and a temperature measuring network and a vacuum press device are provided. The temperature measuring network includes a main control thermocouple located in the middle of the blade body; Auxiliary thermocouples, located at the blade tip, blade root and both sides of the lug; The temperature measurement network is doubly fixed by high-temperature silicone tape and metal clips.

[0051] Specifically, the process of step S4 is as follows: S41, grinding and cleaning the edge area of ​​the semi-finished blade product; S41, applying film to the blade bonding area and performing bag making pre-pumping; S41, install the edge wrapping on the blade, tap it lightly to complete the assembly, and then wrap it tightly with a single-sided adhesive release cloth; S41, covering the blade product with vacuum auxiliary materials; S41, after the blade product is fixed in the autoclave, the vacuum bag auxiliary material is removed and the overflow glue is cleared. Specifically, the vacuum bag auxiliary materials include vacuum bag film, breathable felt, and isolation film. When the blade product is covered with the vacuum auxiliary materials, adhesive tape, isolation film, breathable felt, and vacuum bag film are laid on the surface of the blade product in sequence.

[0052] Specifically, the final inspection includes: inspecting the leading edge of the blade product, the surface flatness and smoothness of the product, the debonding condition of the bonding interface, and whether there are edge burrs; The post-processing includes: cleaning the surface of the blade parts of the excess material, coding marking, and packaging with bubble pads; Exemplarily, the workflow of the method of the present invention is as follows: Specific operation process of blade forming: 1. Raw material preparation After taking out the qualified raw materials from the cold storage, they should be sealed before reaching room temperature. The sealed bag can be opened only after the materials have been thawed for at least 6 hours and there is no moisture on the surface of the sealed bag. Materials with moisture on the roll or in the bag should be discarded. 2. Mold preparation Clean the mold that has passed the inspection with acetone first to confirm that the tooling surface is not damaged, and then apply mold release agent on the mold surface. Apply mold release agent 8 times for the first production mold and 3 times for the reused mold; 3. Cutting Import the blanking drawing into the automatic blanking machine to accurately cut the sheet, with the sheet angle within 0.5°. Arrange the cut sheets in the order of laying, and wrap them with isolation film for laying; 4. Paving Leaf paving is divided into: leaf basin paving, leaf back paving, and ear hanging paving; Place the paving molds directly under the projector, open the corresponding projection file, and check the projection profile with an accuracy of ±0.5mm. Lay out the prepreg in the order of layers. After the first layer of prepreg is laid, make and pre-evacuate the bag. The vacuuming time should be no less than 15 minutes. Then, pre-evacuate every two layers. The vacuuming time should be no less than 15 minutes until the layer is completed. 5. Filling the triangle area After closing the upper and lower molds, tighten them with bolts and place them vertically. Cut the carbon filaments and use a cutter to cut the prepreg into carbon filaments with a width of 2 to 15 mm. Fill the cut carbon filaments into the triangular area and use a pointed rolling board to roll the carbon filaments until the triangular area is filled. 6. Mold closing After the mold is closed and installed, the inclined pressing block is tightened with a copper rod, the connecting bolts and lifting lugs are installed, and the mold is transferred to the press platform; 7. Preloading A. Start the press, slowly increase the pressure to 5MPa, and check that the mold clearance is less than 0.05mm; B. Transfer the mold to the clean room, disassemble the mold, and check the pre-pressed state of the blade basin, blade back, lugs, and filling area. If there is no indentation, add material. If the material protrudes from the mold surface, remove the excess material. C. Preload again until the requirements are met; 8. Curing Insert the thermocouple into the deepest part of the temperature measuring hole and fix it with pressure-sensitive tape. Start the press and run it according to the corresponding curing parameters. Use the thermocouple as the operating temperature and record it every 30 minutes. The curing parameters are as follows: A. Heating / cooling rate 1℃~4℃ / min; B. Staged vacuuming: raise the room temperature to 100°C, keep warm for 2 hours, vacuumize for 10-15 minutes, turn off the vacuuming, keep warm at 100°C for 1 hour, raise the temperature to 160°C, apply pressure to 0.3 MPa, and start vacuuming at the same time. Raise the temperature to 180°C and keep warm for 1 hour, raise the temperature to 220°C and keep warm for 1 hour, and raise the temperature to 250°C and keep warm for 3 hours. C. Maintain pressure and cool to 60℃, release pressure and take out of the tank 9. Demolding After the mold temperature drops to room temperature, demould and remove the blade product, and finally disassemble the lower mold and base plate; 10. Inspection Inspect the appearance, internal quality and surface of parts according to technical requirements; 11. Register and store The surface of the workpiece is labeled, the part number and serial number information are recorded, and it is placed in the semi-finished product warehouse for processing.

[0053] For example, the specific operation process of edge gluing is as follows: 1. Preparation for bonding Use 800-grit sandpaper to roughen the edge area of ​​the blade and clean it with acetone. Then collect the J-486 film. After the material is taken out of the cold storage, it should be sealed before it reaches room temperature. The sealed bag can be opened only after the material has been thawed for at least 6 hours and there is no moisture on the surface of the sealed bag.

[0054] 2. Film laying Lay a layer of 0.05mm thick J-486 polyimide film on the blade bonding area, and lay 4 layers of film on the transition area; make a pre-vacuum bag, vacuum and compact it for more than 15 minutes, and the compaction time starts when the vacuum degree in the vacuum bag reaches ≤-0.085MPa.

[0055] 3. Bonding and edging Install the edging on the blade, tap the edging gently with a hammer to ensure it is in place, and wrap it tightly with a single-sided adhesive release cloth.

[0056] 4. Bag making and packaging The product is bagged. Two rounds of putty strips are applied to the bag-making area: the inner round is ST400, and the outer round is LG230. The inner and outer rounds of putty strips must not cross each other and must be bonded parallel to each other. The following layers are laid on the part surface in the following order: adhesive tape, release film, breathable felt, and finally, vacuum bag.

[0057] 5. Curing Start the autoclave to run the curing program, use the air temperature as the temperature parameter, and record the start and end time of the final curing. The curing parameters are as follows: A. Heating / cooling rate 1℃~4℃ / min; B. Evacuate the entire process, pressurize to 0.3MPa at room temperature, heat to 250℃ and keep warm for 3h; C. Maintain the pressure and cool down to 60℃ before releasing the pressure and unloading the tank.

[0058] 6. Demolding Remove the vacuum bag film, breathable felt, and isolation film from the surface of the part. If there is any overflowing resin block after taking out the part, it needs to be cleaned up.

[0059] 7. Inspection Appearance inspection: Use visual method to check whether the edge bonding position is accurate and whether the edge is deformed.

[0060] 8. Grinding of edge gaps Use paper tape to protect the front edge, and use sandpaper with 400 mesh or above to polish the edge gap to make the flow channel transition smooth.

[0061] 9. Final inspection Visually inspect the front edge; the surface should be flat and smooth, with no burrs on the edges.

[0062] 10. Register and store After the parts have passed the inspection, they need to be cleaned of excess material on the surface, coded and marked, and bubble-wrapped, and then placed on a parts rack or special bracket to avoid collisions and scratches.

[0063] A mold for a high-temperature resistant composite material stator blade, used in the above-mentioned method for manufacturing a high-temperature resistant composite material stator blade, includes a base plate 1, a fence 11 is provided on the base plate 1, a compression molding area is formed between the base plate 1 and the fence 11, an upper mold 2 and a lower mold 3 are provided in the fence 11, the upper mold 2 and the lower mold 3 are buckled together, a side mold assembly 4 is provided in the fence 11, for applying pressure to the sides of the upper mold 1 and the lower mold 2, and the side mold assembly 4 includes a side pressure block 41, a backhoe block 42 and an inclined pressure block 43.

[0064] Furthermore, composite material prepreg is laid on the mold surface of the lower mold 3 to form the back part of the blade. After the laying is completed, the upper mold 2 is then fastened on the lower mold 3, accurately aligned, and locked with bolts so that the laid prepreg forms the blade basin part. At the same time, the outer surface material of the ear is laid on the side pressure block 41, and then the prepreg is supplemented to the triangular area between the side pressure block 41, the lower mold 3 and the upper mold 2. Then, the lower mold 3, the upper mold 2 and the side pressure block 41 are placed on the base plate 1 accordingly, and the enclosure 11, the backhoe block 42 and the inclined pressure block 43 are installed in turn. After the assembly is completed, pre-pressing and curing are carried out. Then, demolding is carried out in the order of first the inclined pressure block 43, the backhoe block 42, the enclosure 11, the side pressure block 41, and finally loosening the bolts of the upper and lower molds 3. Finally, the molded blade is taken out and the mold is cleaned.

[0065] In summary, the present invention improves the molding quality and performance of high-temperature resistant composite stator blades by adopting a vacuum molding process. Compared with the traditional prepreg laying / molding process and preform / RTM process, it solves the technical problems of high internal porosity and poor surface quality of the product. At the same time, through the interlocking pressure of the upper and lower molds, and the side pressure provided by the inclined pressure block, combined with staged vacuuming to achieve multi-sided pressure, uniform flow and full curing of the resin, the dimensional stability and mechanical properties of the blade in high-temperature environments are ensured, and the reliability verification level of the product is improved. In addition, fine grinding and protective technology are used in the edging process, and low-temperature curing and high-temperature resistant adhesives are used for bonding and edging, which makes the blade edge transition smoother, improves the surface quality, and there is almost no deformation of the blade after edging. At the same time, through a series of treatments such as vacuum control, temperature management and quality inspection, the stator blades have excellent internal density.

[0066] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing a high-temperature resistant composite material stator blade, characterized in that: The following steps are involved: S1, material pretreatment and mold preparation: Gradual thawing of the material prepreg, precision inspection of the mold surface, and spraying of high-temperature resistant release agent; S2, Lamination and Pre-compaction: Laser projection is used to locate the layup paths for the blade base, blade back, and lugs, and then the layers are laid in sections, with prepreg filling in the triangular areas. S3, vacuum molding and curing: After the mold is assembled, pre-pressing is performed to check whether there is excess material. Pre-pressing is performed again until the requirements are met, and then pressurization curing is performed. After completion, the semi-finished blade product is demoulded and removed; S4, edge wrapping: Surface treatment of the leading and trailing edges of the blades, laying adhesive film and encapsulation, curing and bonding in an autoclave; S5, Inspection and Post-processing: Inspect the adhesion strength of the blade edge and protect the edge with paper tape. Perform final inspection and post-processing to form the finished blade.

2. The method for manufacturing a high-temperature resistant composite material stator blade according to claim 1, characterized in that: The specific process of step S1 is as follows: first, the prepreg is sealed in an insulation box and transferred to a constant temperature device, and then thawed by gradient heating; A two-stage process is used to clean the mold surface, preheat the mold, and finally apply the release agent in layers through a composite process.

3. The method for manufacturing a high-temperature resistant composite material stator blade according to claim 2, characterized in that: The gradient temperature thawing is specifically as follows: In the first stage, the prepreg material is sealed and transferred to a transition environment at 15°C, where it is left to rise in temperature. In the second stage, the prepreg is then transferred to a standard constant temperature and humidity environment to thaw; The two-stage process includes acetone cleaning and electrostatic dust removal treatment; The specific processing method of the composite process includes spraying the release agent and wiping with non-woven fabric, and the spraying of the release agent and wiping with non-woven fabric are performed alternately.

4. The method for manufacturing a high-temperature resistant composite stator blade according to claim 1, characterized in that: The specific process of step S2 is: S21, importing the laser projection blanking pattern into the automatic blanking machine, and cutting the prepreg into paving sheets; S22, marking the ply sequence number on the edge of each paving sheet, and distinguishing paving sheets in different paving areas by using colored isolation films; S23, arranging the sheets in the order of plying and covering them with an isolation film for dust and moisture proofing; S24, placing the paving molds directly under the projectors, opening the corresponding projection files, and verifying the projection profiles; S25, positioning according to the projection contour, performing paving and bag making pre-drawing alternately according to the plying order until paving is completed; S26, closing and locking the upper mold and the lower mold, and placing them vertically; S27, cutting the paving sheet into carbon filaments with a width of 2 to 15 mm, and filling the triangular area until it is filled.

5. The method for manufacturing a high-temperature resistant composite material stator blade according to claim 4, characterized in that: The paving areas include: leaf basin paving, leaf back paving, and ear paving; The specific steps of performing the laying and bag making pre-extraction alternately in the laying order are as follows: When laying, the prepreg is laid in the order of layers. After the first layer of prepreg is laid, the bag is pre-pumped, and then pre-pumped every two layers until the laying is completed. The vacuuming time of each bag making pre-vacuuming is not less than 15 minutes.

6. The method for manufacturing a high-temperature resistant composite stator blade according to claim 1, characterized in that: In step S3, the pre-pressing treatment specifically includes: performing multi-surface pressurization treatment on the prepreg through a mold; The multi-faceted pressure includes the pressure of the upper and lower molds buckled together, and the side pressure applied by the oblique pressure block to the upper and lower molds through the side pressure blocks; The pressurized curing adopts staged vacuuming.

7. The method for manufacturing a high-temperature resistant composite material stator blade according to claim 1, characterized in that: A temperature measurement network and a vacuum press device are arranged outside the mold. The temperature measurement network includes a main control thermocouple located in the middle of the blade. Auxiliary thermocouples, located at the blade tip, blade root and both sides of the lug; The temperature measurement network is doubly fixed by high-temperature silicone tape and metal clips.

8. The method for manufacturing a high-temperature resistant composite stator blade according to claim 1, characterized in that: The specific process of step S4 is: S41, grinding and cleaning the edge area of ​​the semi-finished blade product; S41, applying film to the blade bonding area and performing bag making pre-pumping; S41, install the edge wrapping on the blade, tap it lightly to complete the assembly, and then wrap it tightly with a single-sided adhesive release cloth; S41, covering the blade product with vacuum auxiliary materials; S41, after the blade product is fixed in the autoclave, the vacuum bag auxiliary materials are removed and the overflowed glue is cleared.

9. The method for manufacturing a high-temperature resistant composite stator blade according to claim 8, characterized in that: The vacuum bag auxiliary materials include vacuum bag film, breathable felt, and isolation film. When the blade product is covered with the vacuum auxiliary materials, the surface of the blade product is sequentially laid with adhesive tape, isolation film, breathable felt, and vacuum bag film. The final inspection includes: inspecting the leading edge of the blade product, the surface flatness and smoothness of the product, the debonding condition of the bonding interface, and whether there are edge burrs; The post-processing includes: cleaning the surface of the blade parts of the redundant materials, coding marking, and packaging with bubble pads.

10. A mold for a high-temperature resistant composite stator blade, used in the method for manufacturing a high-temperature resistant composite stator blade according to any one of claims 1 to 9, comprising a base plate, characterized in that: A fence is provided on the bottom plate, and a die pressing area is formed between the bottom plate and the fence. An upper die and a lower die are provided in the fence, and the upper die and the lower die are buckled together. A side die assembly is provided in the fence for applying pressure to the sides of the upper die and the lower die, and the side die assembly includes a side pressure block, a backhoe block and an inclined pressure block.

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