A method of forming an aero-propeller blade

Abstract

This invention discloses a method for forming aircraft propeller blades, comprising the following steps: 1) blanking; 2) carbon beam forming; 3) blade root wedge forming; 4) carbon tube forming; 5) foam core assembly forming; 5-1) cleaning the mold; 5-2) processing the foam; 5-3) processing the carbon beam; 5-4) preparing the components; 5-5) preparing the sealant and adhesive; 5-6) assembling the foam core; 5-7) laying the carbon beam covering cloth; 5-8) installing the carbon beam; 5-9) applying adhesive; 5-10) installing the foam; 5-11) applying the mold; 5-12) closing the mold; 5-13) inspection; 6) installing the metal blade root jacket; 7) weaving forming; 8) trailing edge strip forming; 9) blade pre-forming; 10) RTM forming. This invention optimizes the process operability, greatly improves the non-destructive quality of the product, solves the problem of excessive adhesive on the blade leading edge caused by blade root movement, and also improves the accuracy of the blade shape.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and in particular to a propeller blade. Background Technology

[0002] Resin-based composite blades can effectively reduce weight and noise. Using resin-based composites to manufacture blades not only significantly reduces blade weight but also substantially reduces engine weight, improving thrust-to-weight ratio and efficiency. Therefore, improving the quality of composite blades can both increase engine efficiency and reduce aviation safety hazards. Currently, domestic composite propeller blade molding uses fabric + RTM molding technology, which has poor quality stability and is prone to defects such as surface dry spots, root delamination, and excessive resin at the leading edge. This blade molding solution employs a hybrid molding method combining autoclave molding, compression molding, and RTM molding, fully utilizing the advantages of each method and effectively avoiding the aforementioned problems.

[0003] The main structure of the composite blade consists of a carbon beam, a polyurethane foam core, an outer carbon fiber and glass fiber woven sleeve, and a polyurethane foam filling layer at the blade root. Its main component is a carbon beam made of alternating layers of unidirectional and satin-textured carbon cloth prepreg. These beams are laid out unevenly and with varying thicknesses along both the blade's axial and thickness directions on both the working and non-working surfaces. They then "clasp" together in a ring shape into the metal blade root sleeve, before widening at the root of the sleeve to form a wedge with open ends. This ensures a complete and reliable connection between the carbon fiber composite load-bearing beam and the metal sleeve. The core of the carbon beam is a PMI foam core, and the outer shell is a blend of glass fiber and carbon fiber, all integrated organically through RTM injection molding.

[0004] When installing the blade preform into the blade root sleeve: the blade preform must first be fixed to the drawing fixture, then a pulling force is applied to the blade root sleeve towards the blade root. After the blade root is pulled into place, a backstop fixture is used to fix the blade root sleeve. However, when the blade preform is pre-shaped, the backstop fixture needs to be removed. At this time, the blade root sleeve is subjected to a reaction force (the reaction force of the drawing force), causing the blade root sleeve to slide towards the blade tip. This results in a difference in the matching between the blade preform and the mold, leading to excessive glue on the leading edge of the blade after RTM glue injection, and a decrease in the accuracy of the blade shape. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for forming aircraft propeller blades, which optimizes process operability, greatly improves the non-destructive quality of the product, solves the problem of excessive adhesive on the leading edge of the blade caused by the movement of the blade root jacket, and also improves the accuracy of the blade shape.

[0006] The objective of this invention is achieved as follows: a method for forming aircraft propeller blades, wherein the blade structure includes a carbon beam, a root wedge, a carbon tube, a foam core, a root inner sleeve, a root outer sleeve, and a woven outer sleeve. The working and non-working surfaces of the foam core are machined with grooves filled by the carbon beam, so that during forming, the surface of the carbon beam blade and part of the foam core assembly blade form a continuous surface. The forming method includes the following steps:

[0007] Step 1) Material cutting: Use an automatic cutting machine to cut each piece of prepreg according to the program.

[0008] Step 2) Carbon beam forming: After cleaning the mold, the carbon beam is laid, cured, machined, inspected, and put into storage for later use. The carbon beam has a conjoined structure, including working surface carbon beam and non-working surface carbon beam. The outer periphery of the root of the carbon beam is machined to form a V-shaped circumferential groove.

[0009] Step 3) After the paddle root is formed by inverted wedge, the mold is cleaned and then the following steps are performed: laying, curing, shaping, testing, and storage for later use.

[0010] Step 4) Carbon nanotube forming: After cleaning the mold, the process includes winding, curing, machining, testing, and warehousing for later use.

[0011] Step 5) Foam core assembly molding,

[0012] Step 5-1) Clean the mold;

[0013] Step 5-2) Process the foam: Wrap the foam core with a clean, porous insulating membrane and breathable felt, and put it into an oven for dehumidification. After dehumidification, evenly wrap a layer of adhesive film on the surface of the foam.

[0014] Step 5-3) Process the carbon beam. After sandblasting the surface of the carbon beam, wipe the surface of the carbon beam with an appropriate amount of acetone using a cotton ball until the cotton ball is free of discoloration, and then let it air dry at room temperature.

[0015] Step 5-4) Prepare the parts. Use degreased gauze dipped in an appropriate amount of acetone to wipe the surface of the counterweight support, carbon tube, paddle root inner sleeve and sealing tool clean until the degreased gauze is free of discoloration, and set aside for use.

[0016] Step 5-5) Prepare the sealant and adhesive. The sealant consists of a base paste, epoxy resin, and a curing agent. First, place the base paste and epoxy resin on a clean polytetrafluoroethylene or clean non-metallic container and mix them repeatedly with a scraper until they are fully mixed. Then, add the curing agent and mix repeatedly with a scraper until the three components are fully mixed. Set aside for use. The adhesive consists of a matrix and a curing agent. Weigh an appropriate amount of the matrix and place it on a clean polyethylene film. Then, add the curing agent and mix and stir until there is no discoloration.

[0017] Steps 5-6) Foam core assembly: Apply sealant evenly to the counterweight support, carbon tube, propeller root inner sleeve, and foam core end face. First, install the carbon tube on the counterweight support, then align the counterweight support with the hole on the foam core and push it into the foam core. Next, insert the sealing fixture into the hole of the counterweight support. Finally, install the end of the propeller root inner sleeve with the sealant applied inward on the sealing fixture and connect it with the carbon tube.

[0018] Steps 5-7) Lay out the carbon beam covering fabric. According to the foam core component layup requirements, lay out the working surface prepreg pieces and the non-working surface prepreg pieces of the carbon beam covering fabric into the upper and lower mold cavities of the foam core component molding mold respectively.

[0019] Steps 5-8) Install the carbon beam. First, apply a layer of adhesive film to the outer surface of the non-working carbon beam. Then, according to the baseline requirements and positioning template, place the non-working carbon beam into the lower mold and press it tightly to fit.

[0020] Steps 5-9) Apply adhesive: Apply the prepared adhesive evenly to the inner surface of the carbon beam root, the outer surface of the carbon tube, and the outer surface of the inner sleeve of the propeller root.

[0021] Steps 5-10) Install the foam: According to the baseline position requirements, install the assembled foam core into the lower mold and press it firmly;

[0022] Steps 5-11) Apply a layer of adhesive film to the outer surface of the carbon beam on the working surface, and then lay the carbon beam on the working surface into the upper mold according to the baseline requirements and the positioning template, and press it tightly to fit.

[0023] Steps 5-12) Mold closing: Close the upper and lower molds together, and then send the mold into a hot press for curing.

[0024] Step 5-13) Detection;

[0025] Step 6) Install the metal propeller root sleeve, attaching the propeller root wedge and propeller root sleeve to the outer periphery of the carbon beam;

[0026] Step 7) Weave and shape the product onto a weaving machine;

[0027] Step 8) The trailing edge strip is formed using high-strength glass fiber and is manually unloaded and molded.

[0028] Step 9) Pre-forming the blades: The woven blades and trailing edge strips are pre-formed using a pre-forming fixture.

[0029] Step 10) RTM molding: The pre-shaped blades are installed into the RTM molding mold and formed into an organic whole through RTM injection.

[0030] As a further limitation of the present invention, the winding in step 4) specifically includes: installing the mandrel onto the winding machine, installing the carbon fiber prepreg roll onto the yarn rack, leading out the carbon fiber strip through the roller, then fixing the carbon fiber prepreg head at the starting position of the mandrel, starting the winding machine, winding according to the winding and layup sequence requirements, and when the winding diameter of the carbon tube reaches the set diameter, turning off the power of the winding machine, cutting the carbon fiber with scissors; and packing the remaining rolls back to the warehouse.

[0031] As a further limitation of the present invention, step 6) includes: cleaning the surfaces of the propeller root wedge and the foam core assembly; preparing an adhesive and applying the adhesive to the V-shaped circumferential groove area around the carbon beam and the inner surface of the propeller root wedge; first, fitting the propeller root outer sleeve onto the root of the foam core assembly; then installing the propeller root wedge into the corresponding position and ensuring it is firmly attached; using a pull-out positioning fixture to pull out the propeller root outer sleeve; and finally, sending it into an oven for curing.

[0032] As a further limitation of the present invention, step 6 specifically includes:

[0033] Step 6-1) Surface treatment: Take the paddle root inverted wedge and foam core assembly, and after sandblasting their outer surfaces, use degreased cotton dipped in an appropriate amount of acetone to wipe the carbon beam surface until the degreased cotton is free of discoloration, and place it to air dry at room temperature;

[0034] Step 6-2) Prepare adhesive: Prepare adhesive according to the weight ratio of matrix: curing agent: silica = 100: 30: 0.3. Apply 50g to 60g of adhesive to each blade. Weigh an appropriate amount of matrix and place it on a clean polyethylene film. Weigh and add curing agent according to the ratio, mix and stir evenly. Weigh and add silica according to the ratio, and continue to stir evenly to obtain the adhesive.

[0035] Step 6-3) Apply adhesive: Apply the prepared adhesive fully to the V-shaped circumferential groove area on the outer periphery of the carbon beam and the inner surface of the inverted wedge at the propeller root;

[0036] Step 6-4) Installation: Slide the paddle root sleeve onto the root of the foam core assembly, with the wedge-shaped flared end facing outwards. Then install the paddle root inverted wedge into the corresponding position and secure it firmly.

[0037] Step 6-5) Pulling: Use a pulling positioning fixture to pull the outer sleeve of the propeller root;

[0038] Step 6-6) Curing: Finally, place in an oven for curing.

[0039] As a further limitation of the present invention, step 6-5) pulling specifically refers to:

[0040] Step 6-5-1) Place the foam core assembly with the working surface facing up on the fixture bracket, make sure the paddle root end face is in contact with the limiting rear cover of the pulling and positioning fixture, fasten the positioning pressure plate, tighten the locking nut of the fixture, and fix the foam core assembly on the fixture.

[0041] Step 6-5-2) Use the sliding pad to adjust the first clamp to a horizontal position and place it directly below the propeller root sleeve. Then align the end face markings of the propeller root sleeve with the end face markings of the clamp. Place the three liner plates into the clamp respectively. Finally, use four bolts to tighten the first clamp and the second clamp.

[0042] (Step 6-5-3) Place the four limit sleeves onto the tie rod, then pass the tie rod through the support plate and clamp, and tighten it with nuts. Insert one pin on each side of the clamp and fix the pins to the clamp with bolts. Rotate the handle to pull the paddle root outer sleeve axially out, ensuring that the four limit sleeves contact the end face of the outer sleeve. Then connect the locking flange to the locking pressure plate with bolts and tighten it.

[0043] As a further limitation of the present invention, step 2) specifically includes:

[0044] Step 2-1) Mold preparation: Clean the mold thoroughly, and then wipe the mold with a mold release agent;

[0045] Step 2-2) Laying: The starting position of the layup is based on the root of the mold blade. Then, lay the cut pieces into the mold cavity one by one. After every 3-6 layers, vacuum pre-compact once. The vacuum degree is less than -0.095MPa and the vacuum time is 10min-15min.

[0046] Steps 2-3) Curing: Increase the temperature at a rate not exceeding 1.5℃ / min to 90℃±5℃ and hold at this temperature for 1h±10min. Continue to increase the temperature at the same rate to 130℃±5℃ and hold at this temperature for 3h±10min. The curing pressure is 1.0MPa±0.05MPa. Decrease the temperature at a rate not exceeding 2℃ / min. When the temperature drops below 45℃, release the pressure and open the mold.

[0047] Steps 2-4) Machining: The carbon beam digital model is used to machine the working carbon beam and the non-working carbon beam. After machining, the appearance is inspected. There are 6 machining thickness detection positions in the range of 0-300mm at the root of the carbon beam, with an accuracy control of ±0.2mm.

[0048] Steps 2-5) Warehousing: Store qualified working surface carbon beams and non-working surface carbon beams in the transit warehouse.

[0049] As a further limitation of the present invention, step 5-5) specifically includes:

[0050] Preparation of sealant: Prepare the sealant according to the weight ratio of base paste: epoxy resin: curing agent = 30:0.9:3; first, place the base paste and epoxy resin on a clean polytetrafluoroethylene or clean non-metallic container and mix them repeatedly with a scraper more than 20 times to make them fully mixed. Then add the curing agent and mix repeatedly with a scraper to make the three components fully mixed. The sealant is then ready for use.

[0051] Prepare the adhesive: Prepare the adhesive according to the weight ratio of substrate:curing agent = 100:30. Apply 50g to 60g of adhesive to each blade. Weigh an appropriate amount of substrate and place it on a clean polyethylene film. Then weigh and add the curing agent according to the ratio. Mix and stir evenly with a clean glass rod until there is no discoloration.

[0052] As a further limitation of the present invention, step 7) specifically includes:

[0053] Step 7-1) Start weaving from the blade root position, with the weaving angle at 45°±5° to the blade axis, i.e., the fiber weaving angle is 90°±10°. Continue weaving for another 15mm to 20mm to the blade tip and then stop. Measure the weaving angle of the blade section and record the measurement results.

[0054] Step 7-2) After each layer is woven, brush a pre-setting adhesive evenly onto the woven layer and let it dry for 3 to 5 minutes;

[0055] Step 7-3) Cut off the fibers from the tip of the blade at the closing position, and use adhesive film to attach the woven layer on the surface to the blade injection molding assembly at three equal parts of the width of the closing position.

[0056] Step 7-4) Remove the extension rod of the blade injection molding assembly from the three-jaw chuck, with the working surface facing up, pass it through the braiding ring from the back of the braiding machine, then clamp the extension rod onto the three-jaw chuck, and fix the fibers to the extension rod with yellow tape;

[0057] Step 7-5) Repeat steps 7-2) to 7-5) until the Nth layer of braiding is completed. During braiding, the non-working surface and working surface of the blade alternately face upwards.

[0058] (Steps 7-6) After weaving N layers, use a bundle of carbon fiber to tightly bind the blade root near the blade blade. Then wrap it with a vacuum bag film, and finally wrap the vacuum bag film tightly.

[0059] Step 7) specifically includes:

[0060] Step 7-1) Start weaving from the blade root position, with the weaving angle at 45°±5° to the blade axis, i.e., the fiber weaving angle is 90°±10°. Continue weaving for another 15mm to 20mm to the blade tip and then stop. Measure the weaving angle of the blade section and record the measurement results.

[0061] Step 7-2) After each layer is woven, brush a pre-setting adhesive evenly onto the woven layer and let it dry for 3 to 5 minutes;

[0062] Step 7-3) Cut off the fibers from the tip of the blade at the closing position, and use adhesive film to attach the woven layer on the surface to the blade injection molding assembly at three equal parts of the width of the closing position.

[0063] Step 7-4) Remove the extension rod of the blade injection molding assembly from the three-jaw chuck, with the working surface facing up, pass it through the braiding ring from the back of the braiding machine, then clamp the extension rod onto the three-jaw chuck, and fix the fibers to the extension rod with yellow tape;

[0064] Step 7-5) Repeat steps 7-2) to 7-5) until the Nth layer of braiding is completed. During braiding, the non-working surface and working surface of the blade alternately face upwards.

[0065] (Steps 7-6) After weaving N layers, use a bundle of carbon fiber to tightly bind the blade root near the blade blade. Then wrap it with a vacuum bag film, and finally wrap the vacuum bag film tightly.

[0066] As a further limitation of the present invention, step 9) specifically includes:

[0067] Step 9-1) Install the glue injection fixture: Fix the blade preform with the anti-reverse fixture removed to the assembly fixture;

[0068] Step 9-2) Place the work surface in the mold and brush with setting adhesive;

[0069] Step 9-3) Fold the back edge strip fabric in half, align the fold line with the back edge of the mold, so that half of the back edge strip fabric is inside the mold cavity and the other half is outside the mold, and apply setting adhesive.

[0070] Step 9-4) Place the blade preform into the mold with the non-working surface facing up, using the front edge of the mold as a reference. Place the rear triangular area into the mold with the rear edge of the braid as a reference. Press down the triangular area and shake the rear edge strip up and down until it is fluffy between layers. When shaking, start from the inflection point of the rear edge strip and gradually extend the shaking towards the blade tip. After shaking and fluffing, gradually press it into the mold cavity so that the rear edge and the edge of the braid fit the mold. Cut off the excess braided fibers at the blade tip according to the size of the mold cavity to ensure that the braid fits the mold cavity.

[0071] Step 9-5) After installing the trailing edge strip, use scissors to trim off the excess skin on the working surface along the mold surface. Do not trim within the range from the paddle root to the 3rd cut surface. Cut open the skin at the joints of each slider.

[0072] Step 9-6) Adhere the two prepreg tapes to the gap between the back edge strip and the braid;

[0073] Step 9-7) Flip up the fabric covering the back edge strip and the fabric covering the sliders, and then use a brush dipped in setting adhesive to smooth the fabric covering the back edge.

[0074] Steps 9-8) Place the non-working surface on the surface of the blade preform and brush it with setting adhesive;

[0075] Step 9-9) Use a vacuum cleaner to remove the cut fibers around the mold and wipe the edges of the mold with acetone;

[0076] Steps 9-10) Close the mold and put it into the drying oven. The mold can be opened only after it has been dried.

[0077] As a further limitation of the present invention, step 10) specifically includes:

[0078] Step 10-1) After completing step 6), remove the blade preform and install it into the RTM molding mold, where it is injected by RTM to form an organic whole.

[0079] Step 10-2) Clean the mold: Check whether the injection port and outlet of the mold are unobstructed. Wipe the surface of the mold several times with degreased gauze dipped in acetone until there is no discoloration. Apply release agent evenly.

[0080] Step 10-3) Install a sealing strip in the sealing groove of the non-working surface mold. The sealing strip interface must be beveled and well-sewn. The interface of the sealing strip cannot be located on the same side of the mold to prevent vacuum leakage due to poor sealing.

[0081] Step 10-4) Place the pre-formed body into the mold with the non-working side facing down, and trim the pre-formed body appropriately according to the mold shape.

[0082] Step 10-5) Mold closing;

[0083] Step 10-6) Mold vacuuming and preheating: Heat the RTM mold and vacuum it. Keep the mold at the set temperature throughout the entire injection process and maintain the temperature until the injection is completed.

[0084] Steps 10-7) Prepare RTM resin;

[0085] Step 10-8) Resin degassing: Open the vacuum valve of the dispensing tank to degas the resin;

[0086] Steps 10-9) RTM Injection: Open the resin flow rate control valve. The injection pressure can be adjusted appropriately within the set range according to the resin flow rate until the resin is dispensed. After the resin is dispensed from the outlet, the injection pressure can be adjusted appropriately within the set range according to the resin flow rate and the presence of air bubbles. After the amount of resin dispensed from the dispensing tank reaches the limit, the vacuuming will stop automatically, and the dispensing valve will be closed to start the resin holding process. If the amount of resin injected exceeds the set amount before the amount of resin dispensed from the dispensing tank reaches the limit, and there are no air bubbles at the mold outlet, the injection process can be ended.

[0087] Step 10-10) Curing, then mold opening;

[0088] Steps 10-11) Detection.

[0089] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention optimizes the shape structure and molding method of the carbon beam and the blade root inverted wedge, and at the same time optimizes and improves the connection method between the foam core component, carbon tube, and blade root jacket and the carbon beam, thereby improving the stability of the blade molding process and the quality of the product without damage, improving the quality consistency of each component of the blade, and providing the preconditions for blade interchangeability. Attached Figure Description

[0090] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0091] Figure 1 This is a process flow diagram of the present invention.

[0092] Figure 2 This is a schematic diagram of the carbon beam mold laying process in this invention.

[0093] Figure 3 This is a schematic diagram of carbon beam detection in this invention.

[0094] Figure 4 This is a schematic diagram of the carbon beam structure in this invention.

[0095] Figure 5 This is a schematic diagram of the inverted wedge structure at the paddle root in this invention.

[0096] Figure 6 This is a schematic diagram of the carbon nanotube structure in this invention.

[0097] Figure 7 This is a schematic diagram of the foam core assembly in this invention.

[0098] Figure 8 This is a schematic diagram of the counterweight support in this invention.

[0099] Figure 9 This is a schematic diagram of the inner sleeve of the propeller root in this invention.

[0100] Figure 10 This is a schematic diagram of the adhesive application position at the paddle root in this invention.

[0101] Figure 11 This is a schematic diagram of the inverted wedge installation at the propeller root in this invention.

[0102] Figure 12 This is a schematic diagram of the pulling process in this invention.

[0103] Figure 13 This is a schematic diagram of the weaving position in this invention.

[0104] Figure 14 This is a schematic diagram of the carbon beam and foam assembly in this invention.

[0105] Among them, 100 carbon beam, 200 propeller root inverted wedge, 300 carbon tube, 400 counterweight support, 500 propeller root inner sleeve, 600 propeller root outer sleeve, 700 foam, 800 trailing edge strip, 901 first pressure plate, 902 second pressure plate, 903 first clamp, 904 second clamp, 905 liner, 906 bolt, 907 limiting sleeve, 908 tie rod, 909 support plate, and 910 pin. Detailed Implementation

[0106] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0107] like Figure 1 The method for forming an aircraft propeller blade shown includes the following steps.

[0108] Step 1) Feeding.

[0109] Based on the digital models of parts such as carbon beam 100, propeller root wedge 200, and carbon tube 300, and using Fibersim software to unfold the spatial curved surface into a planar shape, according to the structural layup scheme, the cutting drawings of parts such as carbon beam 100, propeller root wedge 200, and carbon tube 300 are drawn and imported into the operating system of the automatic cutting machine. The prepreg is placed on the automatic cutting machine bracket, and each piece is cut according to the program to cut out the prepreg layup of carbon beam 100, carbon beam covering fabric, and carbon tube 300, and the corresponding number is marked on each prepreg piece.

[0110] Step 2) Forming of carbon beam 100.

[0111] Step 2-1) Mold preparation: Use clean wiping paper dipped in an appropriate amount of acetone solution to clean the mold until the wiping paper is free of discoloration. Then use clean wiping paper dipped in an appropriate amount of release agent (such as 770NC release agent) to wipe the mold 3-5 times, with an interval of 10-15 minutes between each wipe.

[0112] Step 2-2) Laying: The starting position of the layup is based on the root of the mold blade, and this base point is defined as point A. Figure 2 As shown, the cut pieces are then laid into the mold cavity according to the carbon beam 100 laying table. The first layer is the innermost layer (film-coated surface), and the 66th layer is the outermost layer. The carbon beam 100 laying sequence is layers 1 to 66 plus 9 additional outer layers, for a total of 75 prepreg layers. After laying 3-6 layers, a vacuum pre-compaction is performed, with a vacuum degree less than -0.095MPa and a vacuum time of 10-15 minutes.

[0113] Steps 2-3) Curing: Increase the temperature at a rate not exceeding 1.5℃ / min to raise the mold temperature to 90℃±5℃ and hold it at this temperature for 1h±10min. Continue to increase the temperature at the same rate to 130℃±5℃ and hold it at this temperature for 3h±10min. The curing pressure is 1.0MPa±0.05MPa. Cool down at a rate not exceeding 2℃ / min. When the temperature drops below 45℃, the pressure can be released and the mold opened.

[0114] Steps 2-4) Machining: The carbon beam 100 digital model is used to machine both the working and non-working surfaces of the carbon beam 100. After machining, the appearance is inspected. Six machining thickness detection positions are set within a 0-300mm range at the root of the carbon beam 100, with an accuracy control of ±0.2mm. The detection range and positions are shown below. Figure 3 As shown.

[0115] Steps 2-5) Detection.

[0116] Weighing: Use an electronic scale to weigh the carbon beam 100 on the working surface and the carbon beam 100 on the non-working surface, and record the weight.

[0117] Visual inspection: Check the surface of the carbon beam 100 for defects such as dents, wrinkles, lack of grease, excess grease, and inclusions.

[0118] Internal quality inspection: The internal quality of carbon beam 100 was inspected using an ultrasonic testing instrument.

[0119] Steps 2-6) Warehousing: Store qualified carbon beams 100 for working surfaces and carbon beams 100 for non-working surfaces into the transit warehouse.

[0120] As a load-bearing component of the propeller blade, the original RTM molding process for carbon beam 100 resulted in defects such as delamination at the root and high porosity. Adopting a prepreg + autoclave molding process to prepare carbon beam 100 effectively improves its overall mechanical properties and yield rate, while also reducing porosity, simplifying the process, and enhancing process stability. The final carbon beam 100 obtained is as follows: Figure 4 As shown.

[0121] Step 3) Form the paddle root inverted wedge 200.

[0122] Step 3-1) Mold preparation: Use a plastic scraper to clean the mold surface, opening module, guide pillars, etc., removing any lumps and dirt. Then, use cotton wool (or wiping paper) dipped in an appropriate amount of acetone to clean the mold cavity surface until the cotton wool is colorless. Let it air dry at room temperature for 10 to 15 minutes or more. Use cotton wool (or wiping paper) until there is no color difference and let it air dry at room temperature for 10 to 15 minutes or more. Finally, use cotton wool (or wiping paper) dipped in an appropriate amount of 770NC release agent to evenly wipe the mold cavity surface 3 to 5 times, with an interval of 10 to 5 minutes or more between each wipe. Set aside for use.

[0123] Step 3-2) Laying: According to the requirements of the paddle root inverted wedge 200 layup sequence table, with the large end of the mold as the reference plane, lay the prepreg cut sheet into the lower mold cavity of the inverted wedge forming mold. Vacuuming is performed every 6 layers, with a vacuum degree ≤ -0.095MPa and a vacuuming time of 10min to 15min or more, until all layers are laid.

[0124] Step 3-3) Curing: Initial pressure 8MPa±0.1MPa, mold temperature is increased to 90℃±5℃ at a heating rate not exceeding 1.5℃ / min, and held at this temperature for 60min±10min. The mold temperature is then increased to 130℃±5℃ at the same heating rate, and held at this temperature for 2.5h±10min. The temperature is then reduced to below 45℃ at a cooling rate not exceeding 2℃ / min before the pressure is released and the mold is opened.

[0125] Steps 3-4) Mold opening and repair: After opening the mold with the 200mm inverted wedge at the propeller root, use a flat file to clean the burrs on its edges, and then weigh and record the weight.

[0126] Steps 3-5) Detection.

[0127] Visual inspection: Check the surface of the paddle root inverted wedge 200 for defects such as fiber wrinkles, white spots, damage, and glue buildup.

[0128] Non-destructive testing: Perform ultrasonic testing on the product according to the drawing requirements of the 200mm inverted wedge at the paddle root (Note: If CT testing is performed, one out of every 10 sets may be randomly selected for testing), and attach the test report.

[0129] The outer shape of the root jacket is inspected using a laser scanner (or coordinate measuring machine) (tolerance ±0.3), and an inspection report is attached.

[0130] Steps 3-6) Storage: Store the qualified propeller root chamfers 200 into the transfer warehouse. The obtained propeller root chamfers 200 are as follows: Figure 5 As shown.

[0131] The propeller root inverted wedge 200 is prepared by prepreg + molding process, which can effectively ensure its shape accuracy and facilitate subsequent precision assembly and bonding with carbon beam 100 and propeller root outer sleeve 600.

[0132] Step 4) Carbon tube 300 forming.

[0133] Step 4-1) Mold preparation: Clean the mold cavity surface with a cotton ball (or wiping paper) dipped in an appropriate amount of acetone until the cotton ball is free of discoloration, and let it air dry at room temperature for 10 to 15 minutes or more; use cotton balls (or wiping paper) until there is no discoloration, and let it air dry at room temperature for 10 to 15 minutes or more; finally, use cotton balls (or wiping paper) dipped in an appropriate amount of 770NC release agent to wipe the mold cavity surface evenly 3 to 5 times, with an interval of 10 to 5 minutes or more between each wipe, and set aside for use.

[0134] Step 4-2) Winding and shaping.

[0135] Step 4-2-1) Install the cleaned mandrel onto the winding machine, install the SYT49S / E1302 carbon fiber prepreg roll onto the yarn rack, lead out the carbon fiber strip through the roller, and then fix the carbon fiber prepreg head at the starting position of the mandrel.

[0136] Step 4-2-2) The initial winding speed is controlled at 5~8 r / min, and after it becomes constant, the winding speed is controlled at 10~14 r / min.

[0137] Step 4-2-3) Wind the carbon fiber according to the winding and layup sequence requirements. When the winding diameter of the carbon fiber tube 300 reaches ф94, turn off the power of the winding machine and cut the carbon fiber with scissors; pack the remaining rolls and return them to the warehouse.

[0138] Step 4-3) Curing: Increase the temperature at a rate not exceeding 1.5℃ / min to raise the mold temperature to 90℃±5℃ and hold it at this temperature for 1h±10min. Continue to increase the temperature at the same rate to 130℃±5℃ and hold it for 3h±10min. Then, decrease the temperature to below 45℃ at a rate not exceeding 2℃ / min, release the pressure and demold. The curing pressure is 0.6±0.05MPa.

[0139] Step 4-4) Dimensional machining: Fix the mandrel onto the CNC lathe and machine the carbon tube 300 outer diameter to the set size.

[0140] Steps 4-5) Detection.

[0141] Check the surface of the carbon nanotube 300 for defects such as burrs, stringing, and peeling.

[0142] The product was subjected to ultrasonic testing according to the drawings for carbon nanotube 300, and the test report is attached.

[0143] The dimensions of the carbon tube 300 were measured using vernier calipers, and an inspection report is attached.

[0144] Steps 4-6) Warehousing: Store the qualified carbon nanotubes (CNTs) 300 in the transit warehouse. The obtained CNTs 300 are as follows: Figure 6 As shown.

[0145] Step 5) Molding of Foam 700 core components.

[0146] Step 5-1) Mold preparation: Use a plastic scraper to clean the mold surface, positioning blocks, guide pillars, etc., removing any lumps and dirt. Then, use cotton wool (or wiping paper) dipped in an appropriate amount of acetone to clean the mold cavity surface until the cotton wool is colorless. Let it air dry at room temperature for 10 to 15 minutes or more. Use cotton wool (or wiping paper) until there is no color difference and let it air dry at room temperature for 10 to 15 minutes or more. Finally, use cotton wool (or wiping paper) dipped in an appropriate amount of 770NC release agent to wipe the mold cavity surface evenly 3 to 5 times, with an interval of 10 to 5 minutes between each wipe. Set aside for use.

[0147] Step 5-2) Foam 700 treatment: Wrap the foam 700 core with a clean porous release film and breathable felt, and put it into an oven for dehumidification treatment. Drying temperature: 125℃±5℃, drying time: 2.0h~2.5h; After dehumidification, evenly wrap a layer of adhesive film on the surface of the foam 700.

[0148] Step 5-3) Carbon Beam 100 Treatment: After sandblasting the surface of the carbon beam 100, use degreased cotton (or wiping paper) dipped in an appropriate amount of acetone to wipe the surface of the carbon beam 100 until the degreased cotton (or wiping paper) is free of discoloration, and place it to air dry at room temperature for more than 15 minutes.

[0149] Step 5-4) Component preparation: Use degreased gauze (wiping paper) dipped in an appropriate amount of acetone to wipe the surface of the counterweight support 400, carbon tube 300, paddle root inner sleeve 500 and sealing fixture clean until the degreased gauze (wiping paper) is free of discoloration. Let it stand for more than 10 minutes before use.

[0150] Step 5-5) Prepare adhesives and sealants.

[0151] Step 5-5-1) Sealant preparation: Prepare the sealant according to the ratio of base paste: epoxy resin: curing agent = 30g: 0.9g: 3g (amount for a single blade); first, place the base paste and epoxy resin on a clean polytetrafluoroethylene or clean non-metallic container and mix them repeatedly with a scraper at least 20 times to ensure thorough mixing, then add the curing agent and mix repeatedly with a scraper to ensure thorough mixing of the three components, and set aside for use.

[0152] Step 5-5-2) Adhesive preparation: Prepare the adhesive according to the ratio of substrate to hardener = 100:30 (by weight). Apply 50g to 60g of adhesive to each blade. Weigh an appropriate amount of substrate and place it on a clean polyethylene film. Weigh and add the hardener according to the ratio. Mix and stir evenly with a clean glass rod until there is no discoloration.

[0153] Steps 5-6) Foam 700 core assembly: according to Figure 7 As shown, apply the sealant evenly to the counterweight support 400 (e.g., Figure 8 (as shown), carbon fiber tube 300, propeller root inner sleeve 500 (as shown) Figure 9 As shown), the carbon tube 300 is first installed on the counterweight support 400, then the two protrusions of the counterweight support 400 are aligned with the holes on the foam 700 core and pushed into the foam 700 core. Then the sealing fixture is inserted into the hole of the counterweight support 400. Finally, the end of the propeller root inner sleeve 500 coated with sealant is installed inward on the sealing fixture and connected with the carbon tube 300.

[0154] Steps 5-7) Laying carbon beam 100 wrapping fabric: According to the layup requirements of foam 700 core component, lay the prepreg cut pieces of the working surface and the prepreg cut pieces of the non-working surface into the upper and lower mold cavities of the foam 700 core component molding mold respectively.

[0155] Steps 5-8) Install carbon beam 100: First, apply a layer of adhesive film to the outer surface of carbon beam 100 on the non-working surface. Then, according to the baseline requirements and positioning template, place carbon beam 100 into the lower mold and press it tightly to fit.

[0156] Steps 5-9) Applying adhesive: Apply the prepared adhesive evenly to the root of the carbon beam 100, the inner sleeve of the metal propeller root 500, the outer surface of the carbon tube 300, and the inner sleeve of the composite propeller root 500.

[0157] Steps 5-10) Install Foam 700: According to the baseline position requirements, install the assembled Foam 700 core into the lower mold and press it tightly.

[0158] Step 5-11) Place the prepreg pieces and carbon beam 100 on the working surface into the upper mold cavity.

[0159] Steps 5-12) Mold closing: Fix the end cap to the mold, and then send the mold into the hot press for curing.

[0160] Steps 5-13) Curing: Initial pressure 8MPa±0.1MPa, mold temperature is increased to 130℃±5℃ at a heating rate not exceeding 1.5℃ / min, held at this temperature for 150min±10min, and then cooled to below 45℃ at a cooling rate not exceeding 2℃ / min before pressure is released and the mold is opened.

[0161] Steps 5-14) Detection.

[0162] Visual inspection: Inspect the surface of the 700 core foam assembly for defects such as fiber wrinkles, white spots, damage, and glue buildup.

[0163] Non-destructive testing: Perform ultrasonic testing on the product according to the drawings of the 700 core foam module (Note: If CT testing is performed, one out of every 10 units may be randomly selected for testing), and attach the test report.

[0164] The shape of the foam 700 core assembly was inspected using a laser scanner (or coordinate measuring machine) (tolerance ±0.3), and an inspection report is attached.

[0165] Step 5-15) Warehousing: Store the qualified foam 700 core components in the transit warehouse.

[0166] The Foam 700 core assembly mainly consists of a carbon beam 100, a carbon tube 300, a propeller root inner sleeve 500, a counterweight support 400, a Foam 700 core, and a fabric-covered carbon beam 100. The Foam 700 core has been changed from in-situ foaming to PMI Foam 700 machining, resulting in better consistency in weight and shape accuracy. Other parts are also machined to ensure their dimensions. The fabric-covered carbon beam 100 is cut from prepreg carbon cloth using an automatic cutting machine, achieving a dimensional accuracy of ±0.2mm, which is more consistent than manual cutting using templates. Therefore, the weight deviation of the Foam 700 core assembly prepared using the current process is easier to control than the original process, playing a crucial role in achieving single-blade interchangeability.

[0167] Step 6) Install the paddle root jacket 600.

[0168] Step 6-1) Surface treatment: Take a set of qualified paddle root inverted wedge 200 and a qualified foam 700 core component, and after sandblasting their outer surfaces, use degreased cotton (or wiping paper) dipped in an appropriate amount of acetone to wipe the surface of carbon beam 100 until the degreased cotton (or wiping paper) is free of discoloration, and place it at room temperature to dry for more than 15 minutes.

[0169] Step 6-2) Prepare adhesive: Prepare adhesive according to the ratio of component A: component B: silica = 100:30:0.3 (by weight). Apply 50g to 60g of adhesive to each blade. Weigh an appropriate amount of component A and place it on a clean polyethylene film. Weigh and add component B according to the ratio. Mix and stir evenly with a clean depressor. Weigh and add silica according to the ratio and continue to stir evenly with a depressor.

[0170] Step 6-3) Apply adhesive: according to Figure 10 As shown, the prepared adhesive is fully applied to the "V" shaped part of the carbon beam 100 and the inner and outer surfaces of the blade root wedge 200.

[0171] Step 6-4) Installation: Insert the 600 dummy part of the propeller root sleeve into the root of the 700 foam core assembly, with the wedge-shaped flared end facing outwards. The insertion length should be no less than 55mm. Figure 11 As shown, install the propeller root inverted wedge 200 into the corresponding position and offset it by 10±2°, and then fit it firmly.

[0172] Step 6-5) Pulling, as... Figure 12 As shown.

[0173] Step 6-5-1) Place the foam 700 core assembly with the working surface facing up on the fixture bracket, and ensure that the blade root end face is in contact with the limiting rear cover of the pull-out positioning fixture. Snap on the first positioning pressure plate 901 and the second pressure plate 902 (a thin aluminum washer should be added between the pressure plate and the blade body), and tighten the locking nut of the fixture (the gap between the upper and lower pressure plates should not be greater than 0.5mm) to fix the foam 700 core assembly on the fixture.

[0174] Step 6-5-2) Use the sliding pad to adjust the first clamp 903 to a horizontal position and place it directly below the propeller root sleeve 600. Then align the end face markings of the propeller root sleeve 600 with the end face markings of the two clamps. Place the three liner plates 905 between the two clamps respectively. Finally, use four bolts 906 to tighten the first clamp 903 and the second clamp 904.

[0175] (Step 6-5-3) Place the four limiting sleeves 907 onto the tie rod 908, then pass the tie rod 908 through the support plate 909 and the clamp, and tighten it with nuts. Insert one pin 910 on each side of the clamp, and fix the pins 910 to the clamp with bolts 906. Rotate the handle to pull the paddle root outer sleeve 600 axially out, ensuring that the four limiting sleeves 907 contact the end face of the outer sleeve. Then connect the locking flange to the locking pressure plate with bolts 906 and tighten it.

[0176] Step 6-6) Curing: After being placed at room temperature for 1 hour, transfer the product and tooling into an oven for curing. Heat the oven to 45℃~55℃ and hold for 6h±0.5h. Then, cool the oven to below 35℃ and remove the product.

[0177] Step 7) Weave and shape.

[0178] Step 7-1) From Figure 13 Start weaving at position A as shown in the diagram. The weaving angle is 45°±5° with the blade axis (i.e., the fiber weaving angle is 90°±10°). The weaving layer should be tight and uniform. Continue weaving for another 15mm to 20mm at the blade tip and then stop. Measure the weaving angles at sections 1, 3, 5, and 6 and record the measurement results.

[0179] Step 7-2) After each layer is woven, brush 60-80ml of pre-formed adhesive solution with a concentration of 45g / L evenly onto the woven layer and let it dry for 3-5 minutes.

[0180] Step 7-3) Cut off the fibers at the tip of the blade at the closing position. Use a 20mm×30mm adhesive film (SY-24C-300) to attach the woven layer on the blade injection molding assembly at three equal parts of the width of the closing position.

[0181] Step 7-4) Remove the extension rod of the blade injection molding assembly from the three-jaw chuck, with the working surface (concave side) facing up, and pass it through the braiding ring from behind the braiding machine. Then, clamp the extension rod back onto the three-jaw chuck and fix the 144 fibers to the extension rod with yellow tape.

[0182] Step 7-5) Repeat steps 7-2) to 7-5) until 7 layers of weaving are completed. During weaving, the non-working surface and working surface of the blade alternate upwards.

[0183] Steps 7-6) After completing 7 layers, at a distance B (see...) Figure 13 At 20mm (towards the blade tip), use a bundle of T700 carbon fiber to tightly bind the blade root. Then, wrap a vacuum bag film around the BC area (250mm-300mm long) and then wrap the vacuum bag film tightly with yellow tape.

[0184] Step 8) Forming the trailing edge strip 800: Using high-strength glass fiber, manual blanking and mold closing are employed. This process is essentially the same as the original method. The product obtained after this step, such as... Figure 14 As shown.

[0185] Step 9) Pre-design the blades.

[0186] Step 9-1) Install the hexagonal glue injection fixture: Fix the blade preform with the anti-reverse fixture removed onto the assembly fixture (assemble the hexagonal glue injection fixture), and install the left and right hexagonal blocks onto the fixture "V-blocks". Finally, use the left and right screws to drive the "V" blocks to install the hexagonal blocks into place.

[0187] Step 9-2) Place the skin 1 (working surface) in the mold and brush with 250ml±20ml of setting adhesive. Wrinkles are not allowed, and the allowable overlap size is ≤5mm.

[0188] Step 9-3) Fold the 800 back edge strip in half, cut the seam, align the fold line with the back edge of the mold, so that half of the 800 back edge strip is inside the mold cavity and the other half is outside the mold. Apply setting adhesive and let it air dry for 10 to 15 minutes.

[0189] Step 9-4) Place the blade preform into the mold with the non-working surface facing up, using the front edge of the mold as a reference. Place the rear triangular area into the mold with the rear edge of the braid as a reference. Press down the triangular area and shake the rear edge strip 800 up and down until it is fluffy between layers. When shaking, start from the inflection point of the rear edge strip 800 towards the blade tip, at intervals of about 150mm, and gradually extend the shaking backward. The height of the shaking is 150mm. After shaking and fluffing, gradually press it into the mold cavity so that the rear edge and the edge of the braid fit the mold. Cut off the excess braided fibers at the blade tip according to the size of the mold cavity to ensure that the braid fits the mold cavity.

[0190] Step 9-5) After installing the rear edge strip 800, use scissors to trim off the excess skin on the working surface along the mold surface. Do not cut within the range from the paddle root to the 3rd cut surface. Cut open the skin at the joints of each slider.

[0191] Step 9-6) Attach two 10mm wide prepreg tapes to the gap between the back edge strip 800 and the braid.

[0192] Steps 9-7) Flip up the 800 fabric covering the back edge strip and the fabric covering the sliders, then use a brush dipped in setting adhesive to smooth the back edge fabric covering, and let it air dry for 5 to 10 minutes.

[0193] Steps 9-8) Place the skin (non-working surface) on the surface of the blade preform and brush 250ml±20ml of setting adhesive. Check the skin overlap size. The overlap size is ≤5mm.

[0194] Step 9-9) Use a vacuum cleaner to clean away the cut fibers around the mold and wipe the edges of the mold with acetone.

[0195] (Steps 9-10) Close the mold and place it into the oven. After the mold reaches 100℃±5℃, maintain the temperature for 60-75 minutes. Allow the mold to cool down to below 50℃ in the oven before opening it.

[0196] Step 10) RTM molding: After completing step 6), the blade preform is removed and installed into the RTM molding mold, and then formed into an organic whole through RTM injection.

[0197] Step 10-1) After completing step 6), the blade preform is removed and installed into the RTM molding mold, and then formed into an organic whole through RTM injection.

[0198] Step 10-2) Clean the mold: Check if the injection port and outlet of the mold are unobstructed. Wipe the surface of the mold several times with degreased gauze soaked in acetone until there is no discoloration. After drying for 15 to 20 minutes, apply 3 coats of 700NC release agent evenly, with an interval of 10 to 15 minutes between each coat. The drying time for the last coat must be more than 20 minutes.

[0199] Step 10-3) Install two sets of φ6mm sealing strips in the sealing groove of the non-working surface mold. The interface of the two sets of sealing strips must be beveled and well-sewn. The interface of the two sealing strips cannot be located on the same side of the mold to prevent vacuum leakage due to poor sealing.

[0200] Step 10-4) Place the pre-formed body into the mold with the non-working side facing down, and trim the pre-formed body appropriately according to the mold shape.

[0201] Step 10-5) Mold closing: The mold closing gap should be ≤0.05mm.

[0202] Step 10-6) Mold vacuuming and preheating: Heat the RTM mold to 60℃ and vacuum the mold. The vacuum degree requirement is -0.095MPa to -0.1MPa. The mold is kept at 60℃±5℃ throughout the entire injection process and kept warm until the injection is completed.

[0203] Step 10-7) Prepare RTM resin: Weigh out components A, B and C of 3266 resin according to the ratio A:B:C=50:50:0.5. Component A must be kept at 60℃±5℃ for 1h to 2h before use. Pour component B into component A and stir evenly (5min to 10min). Then pour component C into the mixed solution of components A and B and stir evenly (10min to 15min).

[0204] Step 10-8) Resin degassing: Open the vacuum valve of the dispensing tank to degas the resin. The time is about 20-25 minutes.

[0205] Steps 10-9) RTM Injection: Open the resin flow rate control valve, controlling the resin flow rate at 20-30 g / min (fluctuations between 0-40 g / min are allowed). Adjust the injection pressure appropriately within the range of 0-0.3 MPa based on the resin flow rate until the resin is dispensed. After the resin is dispensed from the outlet, adjust the injection pressure appropriately within the range of 0.02-0.4 MPa based on the resin flow rate and air bubble situation. Once the amount of resin dispensed from the dispensing tank reaches the limit, the vacuuming process will automatically stop. Close the dispensing valve and begin holding the resin at 0.5 MPa for 10-15 minutes. If the resin injection volume exceeds 4000 g (for reference) before the amount of resin dispensed from the dispensing tank reaches the limit, and there are no air bubbles at the mold outlet, the injection process can be terminated.

[0206] Step 10-10) Curing: Heat the mold to 80℃±5℃ at a heating rate of no more than 1.5℃ / min, hold for 60min~70min, continue heating at the same rate to bring the mold temperature to 125℃±5℃, hold for 180min±10min, and then cool the mold to below 50℃ in the furnace before opening the mold.

[0207] The blade prefabrication mainly consists of a blade root inverted wedge 200, a blade root outer sleeve 600, a foam core assembly 700, a trailing edge strip 800, a woven layer, and a blade skin. Only the woven layer, trailing edge strip 800, and skin remain of the fabric material, making quality control easier and faster than the original injection molding process. Furthermore, with the current process, all blade components can be produced in parallel, greatly improving blade production efficiency and shortening the production cycle.

[0208] Steps 10-11) Detection:

[0209] Check the blade surface for defects such as fiber wrinkles, white spots, damage, and glue buildup.

[0210] The product underwent ultrasonic testing according to the drawings of the 700 core foam module, and the test report is attached.

[0211] The blade shape is inspected using a laser scanner (or coordinate measuring machine) (tolerance ±0.3), and an inspection report is attached.

[0212] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for forming aircraft propeller blades, characterized in that, The blade structure includes a carbon beam, a blade root inverted wedge, a carbon tube, a foam core, a blade root inner sleeve, a blade root outer sleeve, and a woven outer sleeve. The working and non-working surfaces of the foam core have grooves filled with carbon beams, ensuring that the surface of the carbon beam blade and part of the foam core assembly blade form a continuous surface during molding. The molding method includes the following steps: Step 1) Material cutting: Use an automatic cutting machine to cut each piece of prepreg according to the program. Step 2) Carbon beam forming: After cleaning the mold, the carbon beam is laid, cured, machined, inspected, and put into storage for later use. The carbon beam has a conjoined structure, including working surface carbon beam and non-working surface carbon beam. The outer periphery of the root of the carbon beam is machined to form a V-shaped circumferential groove. Step 3) After the paddle root is formed by inverted wedge, the mold is cleaned and then the following steps are performed: laying, curing, shaping, testing, and storage for later use. Step 4) Carbon nanotube forming: After cleaning the mold, the process includes winding, curing, machining, testing, and warehousing for later use. Step 5) Molding of the foam core assembly; Step 5-1) Clean the mold; Step 5-2) Process the foam: Wrap the foam core with a clean, porous insulating membrane and breathable felt, and put it into an oven for dehumidification. After dehumidification, evenly wrap a layer of adhesive film on the surface of the foam. Step 5-3) Process the carbon beam. After sandblasting the surface of the carbon beam, wipe the surface of the carbon beam with an appropriate amount of acetone using a cotton ball until the cotton ball is free of discoloration, and then let it air dry at room temperature. Step 5-4) Prepare the parts. Use degreased gauze dipped in an appropriate amount of acetone to wipe the surface of the counterweight support, carbon tube, paddle root inner sleeve and sealing tool clean until the degreased gauze is free of discoloration, and set aside for use. Step 5-5) Prepare the sealant and adhesive. The sealant consists of a base paste, epoxy resin, and a curing agent. First, place the base paste and epoxy resin on a clean polytetrafluoroethylene or clean non-metallic container and mix them repeatedly with a scraper until they are fully mixed. Then, add the curing agent and mix repeatedly with a scraper until the three components are fully mixed. Set aside for use. The adhesive consists of a matrix and a curing agent. Weigh an appropriate amount of the matrix and place it on a clean polyethylene film. Then, add the curing agent and mix and stir until there is no discoloration. Steps 5-6) Foam core assembly: Apply sealant evenly to the counterweight support, carbon tube, propeller root inner sleeve, and foam core end face. First, install the carbon tube on the counterweight support, then align the counterweight support with the hole on the foam core and push it into the foam core. Next, insert the sealing fixture into the hole of the counterweight support. Finally, install the end of the propeller root inner sleeve with the sealant applied inward on the sealing fixture and connect it with the carbon tube. Steps 5-7) Lay out the carbon beam covering fabric. According to the foam core component layup requirements, lay out the working surface prepreg pieces and the non-working surface prepreg pieces of the carbon beam covering fabric into the upper and lower mold cavities of the foam core component molding mold respectively. Steps 5-8) Install the carbon beam. First, apply a layer of adhesive film to the outer surface of the carbon beam on the non-working side. Then, according to the baseline requirements and the positioning template, place the carbon beam on the non-working side into the lower mold and press it tightly to fit. Steps 5-9) Apply adhesive: Apply the prepared adhesive evenly to the inner surface of the carbon beam root, the outer surface of the carbon tube, and the outer surface of the inner sleeve of the propeller root. Steps 5-10) Install the foam: According to the baseline position requirements, install the assembled foam core into the lower mold and press it firmly; Steps 5-11) Apply a layer of adhesive film to the outer surface of the carbon beam on the working surface, and then lay the carbon beam on the working surface into the upper mold according to the baseline requirements and the positioning template, and press it tightly to fit. Steps 5-12) Mold closing: Close the upper and lower molds together, and then send the mold into a hot press for curing. Step 5-13) Detection; Step 6) Install the metal propeller root sleeve, attaching the propeller root wedge and propeller root sleeve to the outer periphery of the carbon beam; Step 7) Weave and shape the product onto a weaving machine; Step 8) The trailing edge strip is formed using high-strength glass fiber and is manually unloaded and molded. Step 9) Pre-forming the blades: The woven blades and trailing edge strips are pre-formed using a pre-forming fixture. Step 10) RTM molding: The pre-shaped blades are installed into the RTM molding mold and formed into an organic whole through RTM injection.

2. The method for forming aircraft propeller blades according to claim 1, characterized in that, Step 4) The winding process specifically includes: installing the mandrel onto the winding machine, installing the carbon fiber prepreg roll onto the yarn rack, leading out the carbon fiber strip through the roller, fixing the carbon fiber prepreg head at the starting position of the mandrel, starting the winding machine, and winding according to the winding and layup sequence requirements. When the carbon tube winding diameter reaches the set diameter, turn off the winding machine power and cut the carbon fiber with scissors; the remaining rolls are packaged and returned to the warehouse.

3. A method for forming aircraft propeller blades according to claim 1 or 2, characterized in that, Step 6) includes: cleaning the surface of the propeller root wedge and the foam core assembly, preparing the adhesive and applying the adhesive to the V-shaped circumferential groove area around the carbon beam and the inner surface of the propeller root wedge, first fitting the propeller root outer sleeve from the root of the foam core assembly, then installing the propeller root wedge into the corresponding position and securing it firmly, using a pull-out positioning tool to pull out the propeller root outer sleeve, and finally sending it into an oven for curing.

4. The method for forming aircraft propeller blades according to claim 3, characterized in that, Step 6) specifically includes: Step 6-1) Surface treatment: Take the paddle root inverted wedge and foam core assembly, and after sandblasting their outer surfaces, use degreased cotton dipped in an appropriate amount of acetone to wipe the carbon beam surface until the degreased cotton is free of discoloration, and place it to air dry at room temperature; Step 6-2) Prepare adhesive: Prepare adhesive according to the weight ratio of matrix: curing agent: silica = 100: 30: 0.

3. Apply 50g to 60g of adhesive to each blade. Weigh an appropriate amount of matrix and place it on a clean polyethylene film. Weigh and add the curing agent according to the ratio, mix and stir evenly. Weigh and add the silica according to the ratio, and continue to stir evenly to obtain the adhesive. Step 6-3) Apply adhesive: Apply the prepared adhesive fully to the V-shaped circumferential groove area on the outer periphery of the carbon beam and the inner surface of the inverted wedge at the propeller root; Step 6-4) Installation: Slide the paddle root sleeve onto the root of the foam core assembly, with the wedge-shaped flared end facing outwards. Then install the paddle root inverted wedge into the corresponding position and secure it firmly. Step 6-5) Pulling: Use a pulling positioning fixture to pull the outer sleeve of the propeller root; Step 6-6) Curing: Finally, put it into the oven for curing.

5. The method for forming aircraft propeller blades according to claim 4, characterized in that, Step 6-5) Pulling is specifically as follows: Step 6-5-1) Place the foam core assembly with the working surface facing up on the fixture bracket, make sure the paddle root end face is in contact with the limiting rear cover of the pulling and positioning fixture, fasten the positioning pressure plate, tighten the locking nut of the fixture, and fix the foam core assembly on the fixture. Step 6-5-2) Use the sliding pad to adjust the first clamp to a horizontal position and place it directly below the propeller root sleeve. Then align the end face markings of the propeller root sleeve with the end face markings of the clamp. Place the three liner plates into the clamp respectively. Finally, use four bolts to tighten the first clamp and the second clamp. Step 6-5-3) Put the four limit sleeves on the pull rod, then pass the pull rod through the support plate and the clamp, and tighten it with nuts. Insert one pin on each side of the clamp and fix the pins on the clamp with bolts. Rotate the handle to pull the paddle root outer sleeve out axially. The position to be pulled out is based on the four limit sleeves contacting the end face of the outer sleeve. Then use bolts to connect the locking flange to the locking pressure plate and tighten it.

6. A method for forming aircraft propeller blades according to claim 1 or 2, characterized in that, Step 2) specifically includes: Step 2-1) Mold preparation: Clean the mold thoroughly, and then wipe the mold with a mold release agent; Step 2-2) Laying: The starting position of the layering is based on the root of the mold blade, and then the cut pieces are laid into the mold cavity in sequence. After every 3-6 layers, vacuum pre-compact is performed once. The vacuum degree is less than -0.095MPa and the vacuuming time is 10min-15min. Steps 2-3) Curing: Increase the temperature at a rate not exceeding 1.5℃ / min to 90℃±5℃, hold at this temperature for 1h±10min, and continue to increase the temperature at the same rate to 130℃±5℃, hold at this temperature for 3h±10min; the curing pressure is 1.0MPa±0.05MPa, and the temperature is decreased at a rate not exceeding 2℃ / min. When the temperature drops below 45℃, release the pressure and open the mold. Steps 2-4) Machining: The carbon beam digital model is used to machine the working carbon beam and the non-working carbon beam. After machining, the appearance is inspected. There are 6 machining thickness detection positions in the range of 0-300mm at the root of the carbon beam, with an accuracy control of ±0.2mm. Steps 2-5) Warehousing: Store qualified working surface carbon beams and non-working surface carbon beams in the transit warehouse.

7. A method for forming aircraft propeller blades according to claim 1 or 2, characterized in that, Step 5-5) specifically involves: Preparation of sealant: Prepare the sealant according to the weight ratio of base paste: epoxy resin: curing agent = 30:0.9:3; first, place the base paste and epoxy resin on a clean polytetrafluoroethylene or clean non-metallic container and mix them repeatedly with a scraper more than 20 times to make them fully mixed. Then add the curing agent and mix repeatedly with a scraper to make the three components fully mixed. The sealant is then ready for use. Prepare the adhesive: Prepare the adhesive according to the weight ratio of substrate:curing agent = 100:

30. Apply 50g to 60g of adhesive to each blade. Weigh an appropriate amount of substrate and place it on a clean polyethylene film. Then weigh and add the curing agent according to the ratio. Mix and stir evenly with a clean glass rod until there is no discoloration.

8. A method for forming aircraft propeller blades according to claim 1 or 2, characterized in that, Step 7) specifically includes: Step 7-1) Start weaving from the blade root position, with the weaving angle at 45°±5° to the blade axis, i.e., the fiber weaving angle is 90°±10°. Continue weaving for another 15mm to 20mm to the blade tip and then stop. Measure the weaving angle of the blade section and record the measurement results. Step 7-2) After each layer is woven, brush a pre-setting adhesive evenly onto the woven layer and let it dry for 3 to 5 minutes; Step 7-3) Cut off the fibers from the tip of the blade at the closing position, and use adhesive film to attach the woven layer on the surface to the blade injection molding assembly at three equal parts of the width of the closing position. Step 7-4) Remove the extension rod of the blade injection molding assembly from the three-jaw chuck, with the working surface facing up, pass it through the braiding ring from the back of the braiding machine, then clamp the extension rod onto the three-jaw chuck, and fix the fibers to the extension rod with yellow tape; Step 7-5) Repeat steps 7-2) to 7-5) until the Nth layer of braiding is completed. During braiding, the non-working surface and working surface of the blade alternately face upwards. (Steps 7-6) After weaving N layers, use a bundle of carbon fiber to tightly bind the blade root near the blade blade. Then wrap it with a vacuum bag film, and finally wrap the vacuum bag film tightly.

9. A method for forming aircraft propeller blades according to claim 1 or 2, characterized in that, Step 9) specifically includes: Step 9-1) Install the glue injection fixture: Fix the blade preform with the anti-reverse fixture removed to the assembly fixture; Step 9-2) Place the work surface in the mold and brush with setting adhesive; Step 9-3) Fold the back edge strip fabric in half, align the fold line with the back edge of the mold, so that half of the back edge strip fabric is inside the mold cavity and the other half is outside the mold, and apply setting adhesive. Step 9-4) Place the blade preform into the mold with the non-working surface facing up, using the front edge of the mold as a reference. Place the rear triangular area into the mold with the rear edge of the braid as a reference. Press down the triangular area and shake the rear edge strip up and down until it is fluffy between layers. When shaking, start from the inflection point of the rear edge strip and gradually extend the shaking towards the blade tip. After shaking and fluffing, gradually press it into the mold cavity so that the rear edge and the edge of the braid fit the mold. Cut off the excess braided fibers at the blade tip according to the size of the mold cavity to ensure that the braid fits the mold cavity. Step 9-5) After installing the trailing edge strip, use scissors to trim off the excess skin on the working surface along the mold surface. Do not trim from the paddle root to the cut surface. Cut open the skin at the joints of each slider. Step 9-6) Adhere the two prepreg tapes to the gap between the back edge strip and the braid; Step 9-7) Flip up the fabric covering the back edge strip and the fabric covering the sliders, and then use a brush dipped in setting adhesive to smooth the fabric covering the back edge. Steps 9-8) Place the non-working surface on the surface of the blade preform and brush it with setting adhesive; Step 9-9) Use a vacuum cleaner to remove the cut fibers around the mold and wipe the edges of the mold with acetone; Steps 9-10) Close the mold and put it into the drying oven. The mold can be opened only after it has been dried.

10. A method for forming aircraft propeller blades according to claim 1 or 2, characterized in that, Step 10) specifically involves: Step 10-1) After completing step 6), remove the blade preform and install it into the RTM molding mold, where it is injected by RTM to form an organic whole. Step 10-2) Clean the mold: Check whether the injection port and outlet of the mold are unobstructed. Wipe the surface of the mold several times with degreased gauze dipped in acetone until there is no discoloration. Apply release agent evenly. Step 10-3) Install a sealing strip in the sealing groove of the non-working surface mold. The sealing strip interface must be beveled and well-sewn. The interface of the sealing strip cannot be located on the same side of the mold to prevent poor sealing and vacuum leakage. Step 10-4) Place the pre-formed body into the mold with the non-working side facing down, and trim the pre-formed body appropriately according to the mold shape. Step 10-5) Mold closing; Step 10-6) Mold vacuuming and preheating: Heat the RTM mold and vacuum it. Keep the mold at the set temperature throughout the entire injection process and maintain the temperature until the injection is completed. Steps 10-7) Prepare RTM resin; Step 10-8) Resin degassing: Open the vacuum valve of the dispensing tank to degas the resin; Steps 10-9) RTM Injection: Open the resin flow rate control valve. The injection pressure can be adjusted appropriately within the set range according to the resin flow rate until the resin is dispensed. After the resin is dispensed from the outlet, the injection pressure can be adjusted appropriately within the set range according to the resin flow rate and the presence of air bubbles. After the amount of resin dispensed from the dispensing tank reaches the limit, the vacuuming will stop automatically, and the dispensing valve will be closed to start the resin holding process. If the amount of resin injected exceeds the set amount before the amount of resin dispensed from the dispensing tank reaches the limit, and there are no air bubbles at the mold outlet, the injection process can be ended. Step 10-10) Curing, then mold opening; Steps 10-11) Detection.

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