CN-121989468-A - Co-curing forming method, core mold and tooling for C-shaped tubular structure with flanging semi-closed cavity

CN121989468ACN 121989468 ACN121989468 ACN 121989468ACN-121989468-A

Abstract

The invention discloses a co-curing molding method, a core mold and a tooling for a semi-closed cavity C-shaped tubular structure with a flanging, wherein the semi-closed cavity C-shaped tubular structure with the flanging is used for a full-flow collaborative process design of the semi-closed cavity C-shaped tubular structure with the flanging, the cavity length and the section size ratio of more than or equal to 5:1, the method comprises the following steps of S1, adaptive parting mold design, S2, preparation of a dual-function water-soluble core mold, S3, preparation of a positioning constraint tooling, S4, paving of dual-station synchronous parting units, S5, sequential combined mold closing and locking, S6, integral co-curing molding, S7, non-contact lossless demolding, matching of the dual-station synchronous paving of the dual-station synchronous parting mold, sequential mold closing and locking, integral co-curing, non-contact lossless demolding, and the like.

Inventors

WANG PENG
SUN LONGGANG
CHAI ZIHUA
WANG HUANKAI
PAN XUYING
WANG BIN
TIAN WENJIE
ZHOU RUN

Assignees

航天海鹰(镇江)特种材料有限公司

Dates

Publication Date: 20260508
Application Date: 20260330

Claims (9)

1. The co-curing molding method of the semi-closed cavity C-shaped tubular structure with the flanging is characterized by comprising the following steps of: S1, designing an adaptive split mode: According to the semi-closed cavity inner cavity sealing characteristic and flanging forming requirement of the tubular structure of the semi-closed cavity C-shaped composite material with the flanging, dividing the product into three matched forming units along the section, wherein the three matched forming units comprise a W component corresponding to the bottom main body and the first side flanging of the tubular structure, a core mold component corresponding to the side wall of the inner cavity of the tubular structure, and an L-shaped component corresponding to the top main body and the second side flanging of the tubular structure; s2, preparing a difunctional water-soluble core mould: Preparing a water-soluble core mould which is completely matched with the inner cavity molded surface of the tubular structure, wherein the water-soluble core mould has the dual functions of a precise paving tool of a core mould assembly and an inner cavity rigid support in a curing process; S3, preparing a positioning constraint tool: preparing an upper die and lower die combined forming tool with a coaxial positioning structure, wherein a lower die of the forming tool is provided with a paving positioning molded surface which is completely matched with a W component, and a closed-loop constraint cavity which is completely matched with the appearance of a product is formed after the upper die and the lower die are combined; s4, paving double-station synchronous sub-units: Paving a W component on the lower die positioning profile of the forming tool, and performing low-temperature compacting and shaping after the paving is finished; s5, sequential combined die locking: The core mould assembly after the paving is accurately and adaptively arranged on the inner side molded surface of the W component through a positioning reference, a corner triangular area formed by splicing the W component and the core mould assembly is subjected to homogeneous filling treatment, an L-shaped component is paved on the top of the outer ring of the combined body of the W component and the core mould assembly after the filling is completed, the edges of the L-shaped component, the W component and the core mould assembly are completely overlapped, and finally, the mould clamping locking of the upper mould and the lower mould is completed through a coaxial positioning structure of a forming tool; s6, integrally co-curing and forming: carrying out vacuum full-package packaging on the whole part after die assembly, and sending the whole part into an autoclave after packaging, and realizing integral co-curing of the W component, the core die component and the L-shaped component through an autoclave curing process; S7, non-contact nondestructive demolding: And after solidification, removing the upper die and the lower die of the forming tool, and continuously flushing a water-soluble core die in the inner cavity of the part by using flowing clean water to completely dissolve and discharge the core die, so as to obtain a finished product of the tubular structure of the semi-closed cavity C-shaped composite material with the flanging, wherein the fiber damage of the inner cavity and the precision of the molded surface are not met.
2. The co-curing molding method of a C-shaped tubular structure with a turned-up half closed cavity according to claim 1, wherein in the step S1, the section of the W component is a double-turned-up W-shaped structure, a first turned-up edge corresponds to a bottom main body of the tubular structure, and a second turned-up edge corresponds to a first turned-up edge of the tubular structure; the section of the L-shaped component is of a single-folded L-shaped structure, the transverse edge of the L-shaped component corresponds to the top main body of the tubular structure, and the vertical edge of the L-shaped component corresponds to the second side flanging of the tubular structure; the section of the core mould component is of a C-shaped structure and is completely matched with the side wall of the inner cavity of the tubular structure.
3. The method for co-curing and forming the C-shaped tubular structure with the flanging semi-closed cavity according to claim 1, wherein in the step S2, the water-soluble core mold is formed by casting a water-soluble hot-melt eutectic salt material, the melting temperature of the water-soluble hot-melt eutectic salt is more than or equal to 180 ℃, and is higher than the curing peak temperature of the prepreg of the composite material, and the solid rigidity is maintained in the curing process without softening deformation.
4. The co-curing and forming method of a C-shaped tubular structure with a turned-up half closed cavity according to claim 1, wherein in the step S2, the preparation of the water-soluble core mold specifically comprises the following steps: S21, uniformly spraying a release agent in a cavity of a core mold forming mold; S22, heating the water-soluble hot-melt eutectic salt to a complete melting state, slowly injecting the water-soluble hot-melt eutectic salt at a constant speed from a single-side cavity opening of a core mold forming mold, and keeping the mold horizontal in the whole injection process, so that bubbles are prevented from being generated in the cavity; and S23, standing the die for at least 24 hours in a constant temperature environment after the material injection is completed, completely solidifying and forming the molten material, and demolding to obtain the water-soluble core die with the compactness of more than or equal to 98%, the surface roughness Ra of less than or equal to 1.6 mu m, and no cracks and burrs.
5. The co-curing molding method of the C-shaped tubular structure with the flanging half-closed cavity, which is disclosed in claim 1, is characterized in that in the step S3, at least 3 groups of coaxial positioning holes and high-precision positioning pins are correspondingly arranged on an upper die and a lower die of the molding tool, and the positioning precision after die assembly is less than or equal to 0.05mm; the edge of the paving positioning profile of the lower die is provided with a limiting clamping groove matched with the flanging of the W component, and the inner wall of the upper die is provided with a pressing profile matched with the flanging of the L-shaped component; In the step S4, the low-temperature compacting and shaping treatment temperature of the W component is 60+/-5 ℃, the vacuum degree is kept to be less than or equal to-0.095 MPa in the hot compacting process, and the pressure maintaining time is 5-10min; The joint degree of the W component and the lower model surface after hot compaction is more than or equal to 99 percent, and no ply slippage and fold defect exists; In the step S4, when the core mould component is paved on the outer surface of the water-soluble core mould, no release cloth is paved on the surface of the water-soluble core mould, the water-soluble hot-melt eutectic salt material and the resin system of the composite material prepreg have no adhesion reaction, and after solidification, the water-soluble hot-melt eutectic salt material can be completely dissolved through clear water without residues.
6. The co-curing molding method of the C-shaped tubular structure with the flanging semi-closed cavity according to claim 1, wherein in the step S5, the homogenized filling treatment of the corner triangular region adopts carbon fiber twisted filaments which are in the same system as the main body of the product, the layering compactness of the corner is ensured to be more than or equal to 95% after filling, the defects of porosity and material shortage are avoided, and the layering of the molded surface, the W component and the core mold component after filling is in smooth transition.
7. The co-curing molding method of the C-shaped tubular structure with the flanging semi-closed cavity according to claim 1, wherein in the step S6, the curing temperature of the autoclave curing process is 120-150 ℃, the curing pressure is 0.3-0.6MPa, the vacuum degree is kept to be less than or equal to-0.09 MPa in the whole process, and the furnace is cooled to below 60 ℃ along with the furnace after the curing is completed, and the furnace is discharged; in the step S7, flowing clear water is adopted to continuously wash the water-soluble core mould for at least 30min, the washing water pressure is 0.2-0.4MPa, no rigid tool is in contact with the inner cavity of the part in the washing process, the fiber integrity rate of the inner cavity of the part after demoulding is 100%, and the profile precision meets the requirements of aerospace-grade products.
8. A dual-function water-soluble core mould for a co-curing molding method of a C-shaped tubular structure with a flanging semi-closed cavity, which is used for the method of claim 1, is characterized in that the core mould is molded by casting water-soluble hot-melt eutectic salt, the melting temperature is more than or equal to 180 ℃, the overall density of the core mould is more than or equal to 98%, and the surface roughness Ra is less than or equal to 1.6 mu m; the outer contour of the core mold is completely matched with the inner cavity molded surface of the C-shaped composite material tubular structure with the flanging semi-closed cavity, and the outer surface of the core mold is provided with a positioning mark for paving the core mold assembly; The mandrel keeps solid rigid support in the curing process of the composite material, and can be completely dissolved by flowing clean water without residue after curing.
9. A mold closing positioning forming tool for a co-curing forming method of a C-shaped composite material tubular structure with a flanging semi-closed cavity, which is used for the method of claim 1, is characterized in that the tool is of an upper mold and lower mold combination structure and comprises a lower mold and an upper mold; The lower die is provided with a paving positioning molded surface which is completely matched with the W component, and the edge of the molded surface is provided with a limiting clamping groove which is matched with the flanging of the W component; At least 3 groups of coaxial positioning holes and high-precision positioning pins are correspondingly arranged on the upper die and the lower die, and the die assembly positioning precision is less than or equal to 0.05mm; And a closed-loop constraint cavity which is completely matched with the shape of the C-shaped composite material tubular structure with the flanging semi-closed cavity is formed between the upper die and the lower die after die assembly, and the inner wall of the upper die is provided with a press-fit molded surface which is matched with the flanging of the L-shaped component.

Description

Co-curing forming method, core mold and tooling for C-shaped tubular structure with flanging semi-closed cavity Technical Field The invention relates to a co-curing forming method, a core mold and a tooling for a C-shaped tubular structure with a flanging semi-closed cavity. Background The carbon fiber resin-based composite material is a key material for core components such as missile cabins, aero-engine special-shaped ducts and the like in the aerospace field, wherein the semi-closed cavity C-shaped composite material has a tubular structure with a flanging and an aspect ratio of more than or equal to 5:1, and has strict requirements on forming precision, structural integrity and mechanical properties. The core pain point of the component is difficult to be compatible with the molding precision of the inner cavity and nondestructive demolding. The existing main stream technology has the inherent defects that a metal hard core mold is stable in support, the demolding difficulty of a large-length-diameter-ratio structure is high, the fiber on the inner wall is easy to damage, the rejection rate is over 50%, the demolding difficulty of a flexible core mold is reduced, the high-temperature curing is easy to deform, the forming precision is insufficient, the cost is high, the demolding problem is avoided by a split secondary gluing technology, the gluing interface strength is low, the integral co-curing of a flanging and a main body cannot be realized, and the high-load service requirement is difficult to meet. The invention provides a new thought for demolding difficult problems, but short plates with unmatched curing temperature areas, insufficient rigidity and single function exist, a full-flow collaborative molding process is not formed, and high-quality stable production of the structure cannot be realized. Disclosure of Invention The invention aims to provide a co-curing molding method, a core mold and a tooling for a C-shaped tubular structure with a flanging semi-closed cavity, so as to solve the problems in the prior art. In order to achieve the above purpose, the present invention provides the following technical solutions: A co-curing molding method of a semi-closed cavity C-shaped tubular structure with a flanging is used for a semi-closed cavity C-shaped composite material tubular structure with a flanging, and the ratio of the cavity length to the cross section size is more than or equal to 5:1, and comprises the following steps: S1, designing an adaptive split mode: According to the semi-closed cavity inner cavity sealing characteristic and flanging forming requirement of the tubular structure of the semi-closed cavity C-shaped composite material with the flanging, dividing the product into three matched forming units along the section, wherein the three matched forming units comprise a W component corresponding to the bottom main body and the first side flanging of the tubular structure, a core mold component corresponding to the side wall of the inner cavity of the tubular structure, and an L-shaped component corresponding to the top main body and the second side flanging of the tubular structure; s2, preparing a difunctional water-soluble core mould: Preparing a water-soluble core mould which is completely matched with the inner cavity molded surface of the tubular structure, wherein the water-soluble core mould has the dual functions of a precise paving tool of a core mould assembly and an inner cavity rigid support in a curing process; S3, preparing a positioning constraint tool: preparing an upper die and lower die combined forming tool with a coaxial positioning structure, wherein a lower die of the forming tool is provided with a paving positioning molded surface which is completely matched with a W component, and a closed-loop constraint cavity which is completely matched with the appearance of a product is formed after the upper die and the lower die are combined; s4, paving double-station synchronous sub-units: Paving a W component on the lower die positioning profile of the forming tool, and performing low-temperature compacting and shaping after the paving is finished; s5, sequential combined die locking: The core mould assembly after the paving is accurately and adaptively arranged on the inner side molded surface of the W component through a positioning reference, a corner triangular area formed by splicing the W component and the core mould assembly is subjected to homogeneous filling treatment, an L-shaped component is paved on the top of the outer ring of the combined body of the W component and the core mould assembly after the filling is completed, the edges of the L-shaped component, the W component and the core mould assembly are completely overlapped, and finally, the mould clamping locking of the upper mould and the lower mould is completed through a coaxial positioning structure of a forming tool; s6, integrally co-curing and forming: carrying out vacuum full-package pac