A molding die and molding method for a composite material leading edge part with wavy sharp corners.

Abstract

This invention discloses a molding die and molding method for a composite material leading edge part with wavy sharp corners. The die includes a planar frame base comprising a bottom frame structure and a supporting plate. An annular main molding die is mounted on the supporting plate, and a wavy sharp corner molding die is fixedly connected to one side of the annular main molding die. The wavy sharp corner molding die includes at least two molding blocks. The molding die lays a wavy sharp corner preform in the part using a wavy sharp corner laying die. After the wavy sharp corner preform is placed in the wavy sharp corner molding die, the pressure from the autoclave is transmitted through the core mold in the preform during the curing process, and the wavy sharp corner shape is formed by the wavy sharp corner molding die and the core mold. An irregular annular main preform is also laid and molded using the annular main molding die. This invention achieves one-time integral molding of complex structures of irregular annular composite materials with wavy sharp corners, and effectively avoids the generation of wrinkles during the laying process of the wavy sharp corner portion.

Description

Technical Field

[0001] This invention relates to, but is not limited to, the field of composite material parts manufacturing, and in particular to a molding die and molding method for a composite material leading edge part with a wavy, sharp corner. Background Technology

[0002] With the continuous development and upgrading of aircraft, low-observable flight technology has received high attention from countries around the world and has become a core competitive advantage in the aviation field.

[0003] The principle of low observability for aircraft is to utilize various technologies to weaken or absorb reflected waves, infrared radiation, and other information, making it difficult for detection systems to detect the reflected waves. Currently, there are many main technologies for achieving low observability for aircraft, including external design features such as serpentine air intakes; coating the aircraft surface with radar-absorbing materials such as ferrite; and infrared stealth technologies such as cooling the aircraft's exhaust nozzles and shielding high-temperature components. However, from the perspective of common development and economy, the integrated structural and functional design is the best, but also the most difficult, low observability technology to manufacture. Such functional structures often have complex and high-precision external shape requirements, posing significant challenges to manufacturing. Summary of the Invention

[0004] The purpose of this invention is to provide a molding die and molding method for a composite material leading edge part with a wavy sharp corner, in order to solve the problem that the current proposed integrated structural and functional parts in aircraft have complex structures and high precision requirements, which bring great difficulties to the manufacturing and molding process.

[0005] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a molding die for a composite material leading edge part with a wavy sharp corner, comprising:

[0006] The system comprises a planar frame base 1, a wave-shaped corner laying mold 16, a wave-shaped corner forming mold 3, an annular main body forming mold 2, and a core mold 22; the wave-shaped corner forming mold 3 includes at least two forming blocks.

[0007] The planar frame base 1 includes a bottom frame structure and a support plate fixedly mounted on the frame structure. The annular main body forming mold 2 is fixedly mounted on the support plate. The wave-shaped sharp corner forming mold 3 is fixedly connected to one side of the annular main body forming mold 2 by screws 15, and the wave-shaped sharp corner forming mold 3 includes at least two forming blocks.

[0008] The composite material leading edge part forming mold is used to lay and form the preform of the wave-shaped corner 23 in the composite material leading edge part by the wave-shaped corner laying mold 16. After the preform of the wave-shaped corner 23 is placed in the wave-shaped corner forming mold 3, the pressure of the autoclave is transmitted through the core mold 22 placed in the preform of the wave-shaped corner 23 during the curing process, and the wave-shaped corner forming mold 3 and the core mold 22 form the shape of the wave-shaped corner 23.

[0009] The composite material leading edge part forming mold is also used to lay and form an irregular ring body 24 preform through the ring body forming mold 2, and its outer surface is consistent with the inner surface of the irregular ring body in the leading edge part.

[0010] Optionally, in the composite material leading edge part forming mold with a wave-shaped sharp corner as described above, the wave-shaped sharp corner laying mold 16 includes: a wave-shaped sharp corner mold frame base 29, columns 17 disposed at both ends of the wave-shaped sharp corner mold frame base 29, and a punch 18 disposed between the two columns 17. The outer surface of the punch 18 is prepared based on the wave-shaped sharp corner 23 surface in the composite material leading edge part.

[0011] Optionally, in the composite material leading edge part forming mold with a wave-shaped sharp corner as described above, the height of the outer surface of the punch 18 in the wave-shaped sharp corner laying mold 16 is 30mm to 50mm greater than the depth of the wave-shaped sharp corner 23.

[0012] The waveform sharp corner forming mold 3 is configured as a block structure, with 2 forming blocks forming 1 waveform sharp corner. The number of forming blocks in the waveform sharp corner forming mold 3 is determined by the structure and number of waveform sharp corners 23 in the composite material leading edge part.

[0013] Each molding block includes a surface area 30 and a connecting area 31. The connecting area 31 is connected to the annular main body molding mold 2 by screws 15. The ends of the molding blocks at both ends of the wave-shaped sharp corner molding mold 3 are fixedly connected to the annular main body molding mold 2 by connecting lugs 14.

[0014] Optionally, in the composite material leading edge part forming mold with wavy sharp corners as described above, the core mold 22 is manufactured by the core mold forming mold 21 through lay-up molding; the core mold forming mold 21 is a concave mold structure, and the core mold forming mold 21 is made of fiber reinforced composite material;

[0015] The waveform sharp corner laying mold 16 is also used for laying and forming the core mold forming mold 21. The outer surface of the waveform sharp corner laying mold 16 is consistent with the inner surface of the waveform sharp corner 23 and the core mold forming mold 21, respectively.

[0016] Secondly, embodiments of the present invention also provide a molding method for a composite material leading edge part with a wavy sharp corner. The molding method for the composite material leading edge part is implemented using a molding die for a composite material leading edge part with a wavy sharp corner as described in any of the above-mentioned embodiments. The composite material leading edge part includes: an irregular annular body 24, and a wavy sharp corner 23 extending outside the irregular annular body 24. The molding method includes the following steps:

[0017] Step 1, manufacturing the core mold forming mold 21, includes: forming the core mold forming mold 21 by laying prepreg on the wave-shaped corner laying mold 16, wherein the wave-shaped corner laying mold 16 is designed based on the wave-shaped corner 23 of the composite material leading edge part, and at least one wave-shaped corner forming area is provided on the laying area. Pre-forming is carried out according to the prepreg laying and cold drawing process, and the core mold forming mold 21 is cured and formed after laying.

[0018] Step 2, manufacturing the core mold 22, includes: laying a preset number of release cloth 25 on the inner surface of the core mold forming mold 21 to control the expansion gap of the core mold 22 during the curing process; pouring the uniformly mixed two-component silicone rubber into the core mold forming mold 21, and demolding after room temperature vulcanization for a preset time to form the core mold 22.

[0019] Step 3, laying out the preform of the corrugated sharp corner 23 of the composite material leading edge part, including: laying prepreg on the corrugated sharp corner laying mold 16 and forming the preform of the corrugated sharp corner 23; wherein, based on the docking requirements of the preform of the corrugated sharp corner 23 with the irregular ring body 24 preform in the subsequent process, a stepped lay-up interface 26 is formed in the docking area of ​​the preform of the corrugated sharp corner 23 during the laying process;

[0020] Step 4, the transfer and positioning of the preform of the wave-shaped sharp corner 23, includes: positioning and installing all the single-sided molding blocks used to form the wave-shaped sharp corner 23 in the wave-shaped sharp corner molding mold 3 on the annular main body molding mold 2; placing the preform of the wave-shaped sharp corner 23 prepared in step 3 on the hollowed-out wave-shaped sharp corner molding mold 3; adjusting the spatial position of the preform of the wave-shaped sharp corner 23 to determine that it is placed at the bottom of the wave-shaped sharp corner molding mold 3; and positioning and installing the other single-sided molding block in the wave-shaped sharp corner molding mold 3 on the annular main body molding mold 2.

[0021] Step 5, arranging the core mold 22, includes: vertically placing the core mold 22 into the V-groove of the preform of the wave-shaped sharp corner 23, and tapping it with a wooden mallet to ensure that the core mold 22 is completely fitted with the preform of the wave-shaped sharp corner 23;

[0022] Step 6, laying out the irregular ring-shaped body 24 preform, including: at the stepped lay-up interface 26 position in the docking area of ​​the corrugated sharp corner 23 preform, after removing the first layer of release film 27, laying out the first layer of lay-up, and then removing the release film 27 layer by layer and laying out the first layer of lay-up, completing the laying out of all lay-up layers at the stepped lay-up interface 26 position of the irregular ring-shaped body 24 preform, forming the irregular ring-shaped body 24 preform, and the irregular ring-shaped body 24 preform and the corrugated sharp corner 23 preform form a preform of the integral composite material leading edge part through the stepped lay-up interface 26;

[0023] Step 7, bag making and sealing, including: after laying the preform of the composite material leading edge part, using a sealing bag 28 to bag and seal the irregular ring body 24 preform and the wave-shaped sharp corner 23 preform. The sealing bag 28 is required to wrap the outer ring and inner ring areas of the wave-shaped sharp corner 23 preform and the irregular ring body 24 preform, and seal the bottom of the outer ring and inner ring areas with the support plate of the planar frame base 1.

[0024] Step 8, Curing: The prepreg is cured in an autoclave according to the curing process parameters for forming the composite material leading edge part.

[0025] Optionally, in the molding method of the composite material leading edge part with wavy sharp corners as described above, in step 1,

[0026] For the undulating, width-to-depth ratio of the wave-shaped sharp corner 23 less than 0.4, in order to avoid wrinkles during the laying process, the laying quality is ensured by making cuts in the prepreg. The cuts are made in the prepreg according to the principle of avoiding the upper and lower R areas 19 in the wave-shaped sharp corner laying mold 16, with the middle part 20 of the upper slope of the wave-shaped sharp corner 23 as the center, and offset upward and downward by 13mm to 25mm, in order to ensure the molding quality of the preform of the wave-shaped sharp corner 23.

[0027] Optionally, in the molding method for the composite material leading edge part with wavy sharp corners as described above, the expansion gap of the mandrel 22 prepared in step 2 is determined by the linear expansion coefficient of the two-component silicone rubber, the initial size of the mandrel 22, and the curing temperature, and its expansion gap is:

[0028] In the formula Indicates the coefficient of linear expansion of two-component silicone rubber, Indicates the initial dimensions of core mold 22, This indicates the temperature change value during the use of core mold 22.

[0029] Optionally, in the molding method of the composite material leading edge part with wavy sharp corners as described above, the method of forming the stepped layup interface 26 in the docking area of ​​the preform of the wavy sharp corner 23 in step 3 is as follows: when laying the preform of the wavy sharp corner 23 on the wavy sharp corner laying mold 16, a laying method of gradually reducing the preset width is adopted, and the width reduction range is 25mm to 50mm. After all the layups are laid, the stepped layup interface 26 is formed. The edge of each layup of the stepped layup interface 26 is separated by an isolation film 27, which facilitates the rapid and accurate docking of the subsequent irregular ring body 24 preform when docking and laying the layers at the stepped layup interface 26.

[0030] Optionally, in the molding method of the composite material leading edge part with wavy sharp corners as described above, step 7 employs a double-ring sealing method starting and ending on the support plate of the planar frame base 1, including:

[0031] A vacuum bag 28 is placed on the outer ring area of ​​the annular main body molding mold 2 on the support plate of the planar frame base 1 and a sealing ring is formed by sealing tape. The vacuum bag 28 wraps the annular main body molding mold 2 and the composite material leading edge part preform on it. After the vacuum bag 28 reaches the top of the annular main body molding mold 2, it folds over to the inner ring space of the annular main body molding mold 2 and wraps its inner ring area. After reaching the support plate of the planar frame base 1 again, an inner ring sealing ring is formed by sealing tape.

[0032] The beneficial effects of this invention are as follows: This invention provides a molding die and molding method for a composite material leading edge part with wavy sharp corners. A one-time integral co-curing mold is designed for irregular annular composite material leading edge parts with wavy sharp corners, and a feasible and easy-to-operate molding method is provided in conjunction with the designed molding die. Using the technical solution provided by this invention, and utilizing the molding die and method of this invention, a one-time integral molding of complex structures of irregular annular composite material with wavy sharp corners can be achieved. This effectively avoids the generation of wrinkles during the laying process of the wavy sharp corner part, cleverly achieves precise docking and combination of the wavy sharp corner part and the annular body, ensures the curing quality of the wavy sharp corner part with a large width-to-depth ratio and complex structure, and reduces the risk of air leakage during the curing process. The technical solution provided by this invention has the following beneficial effects:

[0033] First, in the molding die provided by the present invention, the wave-shaped sharp corner laying die 16 is used both as a laying die for the preformed wave-shaped sharp corner 23 and as a core die 22, thus achieving multiple uses of one die and better surface matching.

[0034] Secondly, by using the wave-shaped corner laying mold 16 to lay the preformed wave-shaped corner 23, the method of cutting at the uphill section effectively avoids the generation of wrinkles during the laying of the wave-shaped corner 23.

[0035] Third, the waveform sharp corner forming mold 3 is cleverly designed to be both connected to the ring body forming mold 2 to form an integral part and can be separated. In the process of laying and forming the waveform sharp corner 23 preform, a stepped layup interface 26 is formed in the docking area between the waveform sharp corner 23 preform and the ring body 24 preform, so as to achieve precise docking and combination of the complex waveform sharp corner 23 preform and the irregular ring body 24 preform, thereby achieving the overall one-time co-curing molding.

[0036] Fourth, in the one-time co-curing molding process of the combined structure, a double-ring sealing method starting and ending on the support plate of the planar frame base 1 is adopted to reduce the risk of air leakage during the curing process. Attached Figure Description

[0037] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0038] Figure 1 This is a schematic diagram of the overall structure of a molding die for a composite material leading edge part with a wavy, sharp corner, according to an embodiment of the present invention. Figure 1 The mold shown has an irregular ring structure;

[0039] Figure 2 for Figure 1 A side view of the molding die for a composite material leading edge part with wavy sharp corners provided in the illustrated embodiment;

[0040] Figure 3 for Figure 1 A schematic diagram of the composite material wave-shaped sharp corner layup mold in the molding die of the composite material leading edge part with wave-shaped sharp corners provided in the embodiment shown;

[0041] Figure 4 for Figure 1 The illustrated embodiment provides a schematic diagram of the core mold forming die and core mold forming process in the molding die for a composite material leading edge part with a wavy, sharp corner.

[0042] Figure 5 This is a schematic diagram of the structure of the composite material leading edge part with wavy sharp corners to be formed in an embodiment of the present invention. Figure 5 The composite material leading edge part shown has an irregular ring structure;

[0043] Figure 6 This is a schematic diagram of the interface between the waveform sharp corner and the irregular ring-shaped body stepped ply in an embodiment of the present invention;

[0044] Figure 7This is a schematic diagram of the packaging and bag-making process for a composite material leading edge part with a wavy sharp corner, as described in an embodiment of the present invention.

[0045] Explanation of reference numerals in the attached figures:

[0046] 1-Flat frame base, 2-Ring-shaped main body molding mold, 3-Wave-shaped sharp corner molding mold, 4-1# molding block, 5-2# molding block, 6-3# shape block, 7-4# shape block, 8-5# molding block, 9-6# molding block, 10-7# molding block, 11-8# molding block, 12-9# molding block, 13-Positioning hole, 14-Connecting ear, 15-Screw, 16-Wave-shaped sharp corner laying mold, 17-Column, 18-Convex model surface, 19-R area, 20-Upward slope center, 21-Core mold molding mold, 22-Core mold, 23-Wave-shaped sharp corner, 24-Irregular ring-shaped main body, 25-Release cloth, 26-Stepped layup interface, 27-Isolation film, 28-Vacuum bag, 29-Flat frame base, 30-Shaped surface area, 31-Connecting area. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0048] As explained in the background section, integrated structural and functional design is the optimal, yet also the most challenging, low-detectability technology to manufacture. However, such functional structures often have complex and high-precision shape requirements, posing significant difficulties in manufacturing.

[0049] This invention addresses the problem of irregular annular composite material leading edge parts with at least one wavy sharp corner (usually multiple wavy sharp corners), a small width-to-depth ratio, and the wavy sharp corners extending beyond the main structure, which present significant molding challenges. The invention proposes a manufacturing requirement to ensure the overall functionality of the aforementioned irregular annular composite material leading edge parts with wavy sharp corners, requiring perfect alignment between the wavy sharp corners and the main irregular annular structure, and co-curing in a single step. Specifically, the invention provides a molding die and molding method for composite material leading edge parts with wavy sharp corners.

[0050] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0051] Figure 1 This is a schematic diagram of the overall structure of a molding die for a composite material leading edge part with a wavy, sharp corner, according to an embodiment of the present invention. Figure 1 The mold shown has an irregular ring structure; Figure 2 for Figure 1 A side view of the molding die for a composite material leading edge part with wavy sharp corners provided in the illustrated embodiment; Figure 3 for Figure 1 The illustrated embodiment provides a schematic diagram of the composite material wave-shaped sharp corner laying mold in the molding die for a composite material leading edge part with wave-shaped sharp corners. The molding die for the composite material leading edge part with wave-shaped sharp corners provided in this embodiment includes: a planar frame base 1, a wave-shaped sharp corner laying mold 16, a wave-shaped sharp corner forming mold 3, an annular main body forming mold 2, and a core mold 22; wherein the wave-shaped sharp corner forming mold 3 includes at least two forming blocks;

[0052] Reference Figures 1 to 3 As shown, the planar frame base 1 includes a bottom frame structure and a support plate fixedly mounted on the frame structure. The annular main body forming mold 2 is fixedly mounted on the support plate. The wave-shaped sharp corner forming mold 3 is fixedly connected to one side of the annular main body forming mold 2 by screws 15, and the wave-shaped sharp corner forming mold 3 includes at least 2 forming blocks.

[0053] The composite material leading edge part forming mold is used to lay and form the preform of the wave-shaped corner 23 in the composite material leading edge part by the wave-shaped corner laying mold 16. After the preform of the wave-shaped corner 23 is placed in the wave-shaped corner forming mold 3, the pressure of the autoclave is transmitted through the core mold 22 placed in the preform of the wave-shaped corner 23 during the curing process, and the wave-shaped corner forming mold 3 and the core mold 22 form the shape of the wave-shaped corner 23.

[0054] The composite material leading edge part forming mold is also used to lay and form an irregular ring body 24 preform through the ring body forming mold 2, and its outer surface is consistent with the inner surface of the irregular ring body in the leading edge part.

[0055] The following specific embodiments illustrate the implementation of the molding die and molding method for composite material leading edge parts with wavy sharp corners provided by the present invention.

[0056] See Figures 1 to 7 As shown, the specific structure of the composite material leading edge part forming mold with wave-shaped sharp corners proposed in the embodiment of the present invention includes the following main structure: planar frame base 1, wave-shaped sharp corner laying mold 16, wave-shaped sharp corner forming mold 3, annular main body forming mold 2, core mold forming mold 21 and core mold 22.

[0057] In this embodiment of the invention, the planar frame base 1 is generally made of metal and includes: a bottom frame structure and a support plate fixedly mounted on the frame structure; the annular main body forming mold 2 is fixedly mounted on the support plate, and the wave-shaped sharp corner forming mold 3 is fixedly connected to one side of the annular main body forming mold 2 by screws 15.

[0058] In an optional embodiment of the present invention, Figure 1 The waveform sharp corner forming mold 3 includes forming blocks 1 to 9 (forming blocks 1# 4, 2# 5, 3# 6, 4# 7, 5# 8, 6# 9, 7# 10, 8# 11, and 9# 12, respectively) as an example.

[0059] It should be noted that the fixed position of the wave-shaped corner forming mold 3 on the annular body forming mold 2 is determined by the protrusion position of the wave-shaped corner 23 in the leading edge part on the irregular annular body 24. The wave-shaped corner forming mold 3 is used for the curing and molding of the wave-shaped corner 23 in the leading edge part of the composite material. It can be connected to the annular body forming mold 2 by screws 15 to form an integral part, or it can be separated.

[0060] In this embodiment, in addition to the above-mentioned annular main body molding mold 2 and wave-shaped corner molding mold 3, the molding mold also includes a wave-shaped corner laying mold 16. The wave-shaped corner laying mold 16 is not installed in the above-mentioned molding mold during the co-curing process, but is used in the process of laying the preformed wave-shaped corner 23 and the core mold molding mold 21.

[0061] The composite material leading edge part molding die provided in this embodiment of the invention is used, on the one hand, to lay and form the preform of the corrugated sharp corner 23 in the composite material leading edge part by means of the corrugated sharp corner laying die 16, such as Figure 2 As shown, after the preform of the wave-shaped sharp corner 23 is placed into the wave-shaped sharp corner forming mold 3, the pressure of the autoclave is transmitted through the core mold 22 placed in the preform of the wave-shaped sharp corner 23 during the curing process, and the wave-shaped sharp corner 23 is formed by the wave-shaped sharp corner forming mold 3 and the core mold 22.

[0062] On the other hand, it is also used to lay and form an irregular ring body 24 preform through the ring body forming mold 2, the outer surface of which is consistent with the inner surface of the irregular ring body in the leading edge part.

[0063] In one implementation of this invention, such as Figure 3 and Figure 4 As shown, the wave-shaped corner laying mold 16 includes: a wave-shaped corner mold frame base 29, columns 17 disposed at both ends of the wave-shaped corner mold frame base 29, and a punch 18 disposed between the two columns 17. The outer surface of the punch 18 is prepared based on the wave-shaped corner 23 surface in the composite material leading edge part.

[0064] To ensure easy operation and improved installation quality when bonding the prepreg of the corrugated corner 23 to the irregular ring-shaped main body 24, the height of the corrugated corner installation mold 16 should not be too high or too low. If the height of the corrugated corner installation mold 16 is too high, the mold's center of gravity will be too high, resulting in unnecessary material costs. If the height of the corrugated corner installation mold 16 is too low, the stepped layup interface 26 between the preformed corrugated corner 23 and the prepreg of the irregular ring-shaped main body 24 will be lower than the corrugated corner 23, resulting in a narrow installation area and making installation difficult and affecting the installation quality.

[0065] In one embodiment of the present invention, the height of the convex model surface 18 of the wave-shaped corner laying mold 16 is 30mm to 50mm greater than the depth of the wave-shaped corner 23; and the wave-shaped corner forming mold 3 is set as a block structure, with 2 forming blocks forming 1 wave-shaped corner. The number of forming blocks in the wave-shaped corner forming mold 3 is determined by the structure and number of the wave-shaped corner 23 in the composite material leading edge part.

[0066] In one implementation of this invention, such as Figure 1 As shown, the wave-shaped sharp corner forming mold 3 is composed of multiple forming blocks (forming block 4#1, forming block 5#2, forming block 6#3, forming block 7#4, forming block 8#5, forming block 9#6, forming block 10#7, forming block 11#8, forming block 12#9 respectively). Each forming block (forming block 4#1, forming block 5#2, forming block 6#3, forming block 7#4, forming block 8#5, forming block 9#6, forming block 10#7, forming block 11#8, forming block 12#9) has a shaped surface area 30 and a connecting area 31. The connecting area 31 of each forming block is positioned and connected to the annular main body forming mold 2 by screws 15. The ends of the forming blocks at both ends of the wave-shaped sharp corner forming mold 3 are fixedly connected to the annular main body forming mold 2 by connecting lugs 14.

[0067] In one embodiment of the present invention, the core mold 22 is manufactured by laying and molding the core mold forming mold 21. The core mold forming mold 21 is a concave mold structure and the material of the core mold forming mold 21 is fiber reinforced composite material. In a specific implementation, the core mold forming mold 21 is formed by laying prepreg on the wave-shaped sharp corner laying mold 16 and curing it.

[0068] It should be noted that in this embodiment of the invention, there is no need to manufacture the molding mold of the core mold forming mold 21 separately; the outer surface of the wave-shaped corner laying mold 16 is consistent with the inner surface of the wave-shaped corner 23 and the core mold forming mold 21, which effectively ensures the matching of the wave-shaped corner 23 and the core mold 22 surface, and avoids quality problems such as internal pores and delamination caused by surface mismatch due to manufacturing errors.

[0069] Based on the molding die for the composite material leading edge part with wavy sharp corners provided in the above embodiments of the present invention, the present invention also provides a molding method for the composite material leading edge part with wavy sharp corners, wherein the molding method for the composite material leading edge part is implemented using the molding die for the composite material leading edge part with wavy sharp corners provided in any of the above embodiments. Figure 5 The diagram shown is a structural schematic of the composite material leading edge part with wavy sharp corners to be formed in an embodiment of the present invention. Figure 5 The composite material leading edge part shown has an overall irregular annular structure. The structure of this composite material leading edge part includes: an irregular annular body 24, and a wavy pointed corner 23 extending outside the irregular annular body 24. The molding method provided by this invention includes the following steps:

[0070] Step 1: Manufacture the core mold forming mold 21;

[0071] Before the composite material leading edge part is laid and molded, a core mold forming mold 21 needs to be prepared in advance. The manufacturing method is as follows: the core mold forming mold 21 is formed by laying prepreg on the wave-shaped corner laying mold 16. The wave-shaped corner laying mold 16 is designed based on the wave-shaped corner 23 of the composite material leading edge part. At least one wave-shaped corner forming area is set on the laying area of ​​the wave-shaped corner laying mold 16. Pre-forming is carried out according to the cold drawing process of prepreg laying. After laying, the core mold forming mold 21 is cured and molded.

[0072] In one embodiment of the present invention, for the wave-shaped sharp corners 23 with small vertical undulations and a narrow width-to-depth ratio (typically, a width-to-depth ratio less than 0.4), to avoid wrinkles during the laying process, slits are made in the prepreg to ensure laying quality. Slits are made in the prepreg according to the principle of avoiding the upper and lower R-zones 19 in the wave-shaped sharp corner laying mold 16, with the upper slope center 20 of the wave-shaped sharp corner 23 as the center, and offset upwards and downwards by 13mm to 25mm, to ensure the forming quality of the preformed wave-shaped sharp corner 23.

[0073] In one embodiment, during step 1, after the first layer is laid, it is cold-pressed once, and then cold-pressed once every 6 layers thereafter. The core mold 21 is cured and formed according to the process curing parameters of the applied prepreg. After curing, the rough edges of the core mold 21 are cut and trimmed before use. The thickness of the core mold 21 prepared in this embodiment is 2mm to 3mm.

[0074] Step 2, manufacture core mold 22;

[0075] A preset number of release cloths 25 are laid on the inner surface of the core mold 21 to control the expansion gap of the core mold 22 during the curing process; the uniformly mixed two-component silicone rubber is poured into the core mold 21, and after vulcanization at room temperature for 24 hours, it is demolded to form the core mold 22 to be used.

[0076] In one implementation of this invention, the expansion gap of the mandrel 22 prepared in step 2 is determined by the linear expansion coefficient of the two-component silicone rubber, the initial size of the mandrel 22, and the curing temperature, and its expansion gap is:

[0077] In the formula Indicates the coefficient of linear expansion of two-component silicone rubber, Indicates the initial dimensions of core mold 22, This indicates the temperature change value during the use of core mold 22.

[0078] Step 3: Lay out the preform of the corrugated sharp corner 23 of the composite material leading edge part;

[0079] Prepreg is laid on the corrugated corner laying mold 16 to form a corrugated corner 23 preform. During the specific laying and forming process of the corrugated corner 23 preform, cold compaction is performed according to the principle of vacuuming for more than 10 minutes after the first layer is laid, followed by vacuuming every three layers. Since the corrugated corner 23 and the irregular annular body 24 in the leading edge part are an integral structure, but the corrugated corner 23 has a complex structure and cannot be integrally laid and formed with the irregular annular body 24, the corrugated corner 23 preform needs to be laid and formed separately first. After all layers are laid, the corrugated corner 23 preform is bagged, placed in a can, and hot-compacted to ensure the density between prepreg layers and increase hardness, which helps in the subsequent transfer and positioning of the corrugated corner 23 onto the corrugated corner forming mold 3. The pre-compacting temperature is 70℃~90℃, and the holding time is not less than 30 minutes.

[0080] It should be noted that, based on the docking requirements between the preformed corrugated corner 23 and the irregular ring-shaped main body 24 in subsequent processes, a stepped layup interface 26 is required to be formed in the docking area of ​​the preformed corrugated corner 23 during the laying process.

[0081] In one implementation of this invention, the method for forming a stepped layup interface 26 in the docking area of ​​the preformed corrugated corner 23 is as follows: when laying the preformed corrugated corner 23 on the corrugated corner laying mold 16, a laying method of gradually reducing the preset width is adopted, with the width reduction range being 25mm to 50mm. After all the layups are laid, a stepped layup interface 26 is formed. The edges of each layup layer of the stepped layup interface 26 are separated and isolated using an isolation film 27, which facilitates the rapid and accurate docking of the subsequent irregular ring-shaped body 24 preformed body when docking and laying the layers at the stepped layup interface 26.

[0082] Step 4, transfer and positioning of the preform with waveform sharp corner 23;

[0083] All the single-sided molding blocks used to form the waveform sharp corner 23 in the waveform sharp corner forming mold 3 are fixedly installed on the annular main body forming mold 2. The waveform sharp corner 23 preform prepared in step 3 is placed on the hollow waveform sharp corner forming mold 3. After adjusting the spatial position of the waveform sharp corner 23 preform to determine that it is placed at the bottom of the waveform sharp corner forming mold 3, the other single-sided molding blocks in the waveform sharp corner forming mold 3 are fixedly installed on the annular main body forming mold 2.

[0084] In one alternative embodiment of the invention, such as Figure 1 The nine forming blocks (including forming block 4, 5, 6, 7, 8, 9, 10, 11, and 12) in the waveform sharp corner forming mold 3 shown are designed based on the actual shape of the waveform sharp corner 23 in the leading edge part to be formed. First, forming blocks 4, 6, 8, 10, 11, and 12 are positioned and installed on the annular main body forming mold 2 through their respective connecting areas 31 using screws 15; then the waveform sharp corner 23 is pre-formed. The shape is demolded from the wave-shaped corner laying mold 16, and the demolded wave-shaped corner 23 preform is placed on the hollowed-out wave-shaped corner forming mold 3. The molding status of the wave-shaped corner 23 preform is observed through the missing 2# forming block 5, 4# forming block 7, 6# forming block 9, and 8# forming block 11. After adjusting the spatial position of the wave-shaped corner 23 preform to ensure that it is placed at the bottom of the wave-shaped corner forming mold 3, the 2# forming block 5, 4# forming block 7, 6# forming block 9, and 8# forming block 11 are positioned and installed on the annular main body forming mold 2 through their respective connecting areas 31 using screws 15.

[0085] Step 5, arrange the core mold 22;

[0086] The core mold 22 is vertically placed into the V-groove of the preform with the corrugated sharp corner 23, and the core mold 22 is tapped with a wooden mallet until it is completely fitted to the preform with the corrugated sharp corner 23.

[0087] Step 6: Lay out the irregular ring-shaped preform 24;

[0088] At the stepped layup interface 26 in the preform mating area of ​​the wave-shaped sharp corner 23, the position of the first layer of release film 27 is located and removed intact. Then, the first layer of the irregular ring body 24 is mated and laid. Subsequently, following the above method, the release films 27 are removed layer by layer and mated and laid, completing the mating and laying of all layers at the stepped layup interface 26 of the prepreg of the irregular ring body 24.

[0089] This step involves vacuuming after the first layer of prepreg is laid, followed by vacuuming every three layers of prepreg for cold compaction.

[0090] Step 7, bag making and sealing;

[0091] After the preform of the composite material leading edge part is laid, it is bagged and sealed with auxiliary materials. The specific requirements are: use sealing bags 28 to bag and seal the irregular ring body 24 preform and the wave-shaped sharp corner 23 preform. The sealing bags 28 are required to wrap the outer and inner ring areas of the wave-shaped sharp corner 23 preform and the irregular ring body 24 preform, and seal the bottom of the outer and inner ring areas with the support plate of the planar frame base 1.

[0092] It should be noted that the bag-making and sealing method for the irregular ring-shaped preform 24 and the wavy sharp-corner preform 23 in this step cannot be used. A double-ring sealing method starting and ending on the support plate of the planar frame base 1 is required. The specific bag-making and sealing method is as follows:

[0093] A vacuum bag 28 is placed on the outer ring area of ​​the annular main body molding mold 2 on the support plate of the planar frame base 1, and an outer ring seal is formed by sealing tape. The vacuum bag 28 wraps the annular main body molding mold 2 and the preformed composite material leading edge part on it. After the vacuum bag 28 reaches the top of the annular main body molding mold 2, it folds over into the inner ring space of the annular main body molding mold 2, wrapping its inner ring area. After reaching the support plate of the planar frame base 1 again, an inner ring seal is formed by sealing tape. Because for irregular annular composite material leading edge parts with wavy sharp corners 23, the wavy sharp corner molding mold 3 used is mostly made of segmented splicing, and the risk of air leakage during the curing process is relatively large, direct bag sealing should be avoided.

[0094] Step 8, Curing: The prepreg is cured in an autoclave according to the curing process parameters for forming the composite material leading edge part.

[0095] This invention addresses the challenges of molding irregular annular composite material leading-edge parts with at least one (usually multiple) wavy sharp corners, small aspect ratios, and protruding beyond the main structure, presenting significant molding difficulties. The invention proposes a manufacturing requirement to ensure the overall functionality of these parts, ensuring perfect alignment between the wavy sharp corners and the main irregular annular structure, and achieving one-time co-curing. A molding die and method for forming composite material leading-edge parts with wavy sharp corners are proposed. Specifically, a one-time integral co-curing die is designed for these parts, and a feasible and easy-to-operate molding method is provided in conjunction with the designed die. Using the technical solution provided by this invention, and utilizing its molding die and method, one-time integral molding of complex composite material structures with wavy sharp corners can be achieved. This invention effectively avoids wrinkles during the installation of the corrugated sharp corners, cleverly achieving precise alignment and combination between the corrugated sharp corners and the ring-shaped main body. It ensures the curing quality of the corrugated sharp corners, which have a large width-to-depth ratio and complex structure, and reduces the risk of air leakage during curing. The technical solution provided by this invention has the following beneficial effects:

[0096] First, in the molding die provided by the present invention, the wave-shaped sharp corner laying die 16 is used both as a laying die for the preformed wave-shaped sharp corner 23 and as a core die 22, thus achieving multiple uses of one die and better surface matching.

[0097] Secondly, by using the wave-shaped corner laying mold 16 to lay the preformed wave-shaped corner 23, the method of cutting at the uphill section effectively avoids the generation of wrinkles during the laying of the wave-shaped corner 23.

[0098] Third, the waveform sharp corner forming mold 3 is cleverly designed to be both connected to the ring body forming mold 2 to form an integral part and can be separated. In the process of laying and forming the waveform sharp corner 23 preform, a stepped layup interface 26 is formed in the docking area between the waveform sharp corner 23 preform and the ring body 24 preform, so as to achieve precise docking and combination of the complex waveform sharp corner 23 preform and the irregular ring body 24 preform, thereby achieving the overall one-time co-curing molding.

[0099] Fourth, in the one-time co-curing molding process of the combined structure, a double-ring sealing method starting and ending on the support plate of the planar frame base 1 is adopted to reduce the risk of air leakage during the curing process.

[0100] While the embodiments disclosed in this invention are as described above, they are merely illustrative of the embodiments to facilitate understanding of the invention and are not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A molding die for a composite material leading edge part with a wavy, sharp corner, characterized in that, include: Planar frame base (1), wave-shaped corner laying mold (16), wave-shaped corner forming mold (3), ring-shaped main body forming mold (2) and core mold (22); The planar frame base (1) includes a bottom frame structure and a support plate fixedly mounted on the frame structure. The annular main body forming mold (2) is fixedly mounted on the support plate. The wave-shaped sharp corner forming mold (3) is fixedly connected to one side of the annular main body forming mold (2) by screws (15). The wave-shaped sharp corner forming mold (3) includes at least two forming blocks. The composite material leading edge part forming mold is used to lay and form the preform of the wave-shaped corner (23) in the composite material leading edge part by using the wave-shaped corner laying mold (16). After the preform of the wave-shaped corner (23) is placed in the wave-shaped corner forming mold (3), the pressure of the autoclave is transmitted during the curing process by the core mold (22) placed in the preform of the wave-shaped corner (23), and the wave-shaped corner (23) is formed by the wave-shaped corner forming mold (3) and the core mold (22). The composite material leading edge part forming mold is also used to lay and form an irregular ring body (24) preform through the ring body forming mold (2), and its outer surface is consistent with the inner surface of the irregular ring body in the leading edge part; The core mold (22) is manufactured by laying and molding the core mold forming mold (21); the core mold forming mold (21) is a concave mold structure, and the core mold forming mold (21) is made of fiber reinforced composite material; The waveform corner laying mold (16) is also used for laying and forming the core mold forming mold (21). The outer surface of the waveform corner laying mold (16) is consistent with the inner surface of the waveform corner (23) and the core mold forming mold (21).

2. The molding die for a composite material leading edge part with a wavy, sharp corner as described in claim 1, characterized in that, The waveform sharp corner laying mold (16) includes: waveform sharp corner mold frame base (29), columns (17) set at both ends of the waveform sharp corner mold frame base (29), and punch (18) set between the two columns (17). The outer surface of the punch (18) is prepared based on the waveform sharp corner (23) profile in the composite material leading edge part.

3. The molding die for a composite material leading edge part with a wavy, sharp corner according to claim 2, characterized in that, The height of the outer surface of the punch (18) in the waveform sharp corner laying mold (16) is 30mm to 50mm greater than the depth of the waveform sharp corner (23); The waveform sharp corner forming mold (3) is configured as a block structure, with 2 forming blocks forming 1 waveform sharp corner. The number of forming blocks in the waveform sharp corner forming mold (3) is determined by the structure and number of waveform sharp corners (23) in the composite material leading edge part. Each molding block includes a surface area (30) and a connecting area (31). The connecting area (31) is connected to the annular body molding mold (2) by screws (15). The ends of the molding blocks at both ends of the wave-shaped corner molding mold (3) are fixedly connected to the annular body molding mold (2) by connecting ear pieces (14).

4. A method for molding a composite material leading edge part with a wavy, sharp corner, characterized in that, A molding method for a composite material leading edge part is implemented using a molding die for a composite material leading edge part with a wavy sharp corner as described in any one of claims 1 to 3. The composite material leading edge part includes: an irregular annular body (24) and a wavy sharp corner (23) extending outside the irregular annular body (24). The molding method includes the following steps: Step 1, manufacturing the core mold forming mold (21), including: forming the core mold forming mold (21) by laying prepreg on the wave-shaped corner laying mold (16), wherein the wave-shaped corner laying mold (16) is designed based on the wave-shaped corner (23) of the composite material leading edge part, and at least one wave-shaped corner forming area is provided on the laying area, pre-forming is carried out according to the prepreg laying and cold drawing process, and the core mold forming mold (21) is cured and formed after laying; Step 2, manufacturing the core mold (22), including: laying a preset number of release cloth (25) on the inner surface of the core mold forming mold (21) to control the expansion gap of the core mold (22) during the curing process; pouring the uniformly mixed two-component silicone rubber into the core mold forming mold (21), and demolding after room temperature vulcanization for a preset time to form the core mold (22). Step 3, laying out the preform of the corrugated corner (23) of the composite material leading edge part, including: laying out prepreg on the corrugated corner laying mold (16) and forming the corrugated corner (23) preform; wherein, based on the docking requirements of the corrugated corner (23) preform with the irregular ring body (24) preform in the subsequent process, a stepped lay-up interface (26) is formed in the docking area of ​​the corrugated corner (23) preform during the laying process. Step 4, the transfer and positioning of the waveform sharp corner (23) preform includes: positioning and installing all the single-sided molding blocks used to form the waveform sharp corner (23) in the waveform sharp corner molding mold (3) on the annular main body molding mold (2); placing the waveform sharp corner (23) preform prepared in step 3 on the hollow waveform sharp corner molding mold (3); adjusting the spatial position of the waveform sharp corner (23) preform to determine that it is placed at the bottom of the waveform sharp corner molding mold (3); and positioning and installing the other single-sided molding block in the waveform sharp corner molding mold (3) on the annular main body molding mold (2). Step 5, arranging the core mold (22), including: vertically placing the core mold (22) into the V-groove of the waveform sharp corner (23) preform, and tapping it with a wooden mallet to ensure that the core mold (22) is completely in contact with the waveform sharp corner (23) preform; Step 6, lay up the irregular ring body (24) preform, including: at the stepped layup interface (26) position of the corrugated corner (23) preform, remove the first layer of isolation film (27) and lay up the first layer of layup, then remove the isolation film (27) layer by layer and lay up the first layer of layup, and then lay up the first layer of layup layer by layer, and complete the laying up of all layup layers at the position of the stepped layup interface (26) of the irregular ring body (24) prepreg, forming the irregular ring body (24) preform, and the irregular ring body (24) preform and the corrugated corner (23) preform form the preform of the integral composite material front edge part through the stepped layup interface (26); Step 7, bag making and sealing, including: after laying the preform of the composite material leading edge part, using a sealing bag (28) to bag and seal the irregular ring body (24) preform and the wave-shaped sharp corner (23) preform. The sealing bag (28) is required to wrap the outer ring and inner ring areas of the wave-shaped sharp corner (23) preform and the irregular ring body (24) preform, and seal the bottom of the outer ring and inner ring areas with the support plate of the planar frame base (1). Step 8, Curing: The prepreg is cured in an autoclave according to the curing process parameters for forming the composite material leading edge part.

5. The molding method for a composite material leading edge part with a wavy sharp corner according to claim 4, characterized in that, In step 1, For the undulating and width-to-depth ratio of the waveform sharp corner (23) less than 0.4, in order to avoid the formation of wrinkles during the laying process, the laying quality is ensured by cutting the prepreg. According to the principle of avoiding the upper and lower R areas (19) in the waveform sharp corner laying mold (16), and taking the middle part (20) of the upper slope of the waveform sharp corner (23) as the center, the cutting is made on the prepreg by offsetting it upward and downward by 13mm to 25mm, so as to ensure the molding quality of the waveform sharp corner (23) preform.

6. The molding method for a composite material leading edge part with a wavy sharp corner according to claim 4, characterized in that, The expansion gap of the mandrel (22) prepared in step 2 is determined by the linear expansion coefficient of the two-component silicone rubber, the initial size of the mandrel (22), and the curing temperature. The expansion gap is: In the formula Indicates the coefficient of linear expansion of two-component silicone rubber, Indicates the initial dimensions of the core mold (22), This represents the temperature change value during the use of the core mold (22).

7. The molding method for a composite material leading edge part with a wavy sharp corner according to claim 4, characterized in that, In step 3, the method of forming a stepped layup interface (26) in the docking area of ​​the preform of the waveform sharp corner (23) is as follows: when laying the preform of the waveform sharp corner (23) on the waveform sharp corner laying mold (16), the laying method of gradually reducing the preset width is adopted, and the width reduction range is 25mm to 50mm. After all the layup layers are laid, a stepped layup interface (26) is formed. Each layup edge of the stepped layup interface (26) is separated by an isolation film (27) to facilitate the rapid and accurate docking of the subsequent irregular ring body (24) preform when docking at the stepped layup interface (26).

8. The molding method for the composite material leading edge part with wavy sharp corners according to claim 4, characterized in that, In step 7, a double-ring sealing method is adopted, starting and ending on the support plate of the planar frame base (1), including: A vacuum bag (28) is placed on the outer ring area of ​​the annular main body molding mold (2) on the support plate of the planar frame base (1) and an outer ring seal is formed by sealing tape. The annular main body molding mold (2) and the composite material leading edge part preform on it are wrapped by the vacuum bag (28). After the vacuum bag (28) reaches the top of the annular main body molding mold (2), it is folded into the inner ring space of the annular main body molding mold (2) and wrapped in its inner ring area. After reaching the support plate of the planar frame base (1) again, an inner ring seal is formed by sealing tape.

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