Method for curing black box composite material
By combining staged temperature control and vacuum negative pressure technology, the foam collapse and interface bonding problems of composite materials in the black box shell were solved, the overall performance and reliability of the material were improved, and the high performance requirements of the black box were met.
Patent Information
- Application Number
- CN202511096155.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-06
- Publication Date
- 2025-10-17
AI Technical Summary
In the existing technology, during the co-curing process of PBO fiber/epoxy resin prepreg with metal parts and foam materials, there are problems such as foam structure failure, weak interface bonding and conflicting process parameters, resulting in the performance of the black box shell not meeting the standards.
The use of a staged temperature control process and a vacuum negative pressure process, through vacuum bag pretreatment, staged heating and pressure maintenance treatment, ensures the cross-linking of the resin matrix and the stability of the composite material, avoids foam collapse and interface stratification, and improves the overall strength and heat resistance of the material.
The stable curing of the composite material is achieved, the impact resistance and high temperature resistance of the black box shell are improved, and the performance stability and reliability of the material are ensured.
Smart Images
Figure CN120792210A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of composite material curing molding technology, and in particular to a black box composite material curing method. BACKGROUND
[0002] The throwaway black box is a flight data recorder that can be ejected automatically and float on the water surface in an aviation accident. Due to its special use scene and functional requirements, the black box needs to have excellent performance in high impact resistance, high temperature resistance, low temperature resistance, corrosion resistance and waterproof, lightweight, fatigue resistance, electromagnetic interference resistance, floatability and the like. Therefore, the performance requirements of the throwaway black box for the shell material are extremely strict. At present, the alloy material or carbon fiber / epoxy resin prepreg is usually used to make the shell of the black box. Due to the poor wave-penetrating performance of the metal material and the carbon fiber / epoxy resin composite material, a shielding effect is generated, which causes the positioning of the black box to be difficult, and it is difficult to meet the strict requirements of the black box for the material performance.
[0003] In recent years, researchers have combined high-toughness resin (epoxy resin) matrix with high-strength fiber (organic fiber) to prepare a composite material for manufacturing the shell of the black box. For example, PBO fiber / epoxy resin composite material has become the preferred composite material for manufacturing the shell of the throwaway black box due to its higher specific strength, heat resistance and excellent wave-penetrating performance. However, the performance of the composite material is highly dependent on the curing process, but the co-curing of the PBO fiber / epoxy resin prepreg with metal parts and foam materials still faces challenges, such as the high curing temperature of high-temperature epoxy resin, which causes the foam to collapse under pressure (for example, polyurethane foam softens and deforms at > 150℃), and the existing gradient curing process (patent CN113771465A) cannot balance the resin flow control and foam structure stability.
[0004] At present, there are few researches on composite material black box shells at home and abroad, and no relevant public patents and corresponding materials have been collected to solve the following problems related to composite material black box shells:
[0005] (1) Foam structure failure: the curing pressure and curing temperature required by the traditional prepreg easily cause the foam to soften and deform, and lose the supporting function;
[0006] (2) Weak interface bonding: microcracks are generated between the resin and the metal parts due to the difference in thermal expansion coefficient, which reduces the overall strength;
[0007] (3) Process parameter conflict: high-temperature curing is beneficial to the crosslinking of the resin, but it will exacerbate the collapse of the foam; SUMMARY
[0008] In order to solve the above technical problems, the present application provides a black box composite material curing method to solve the problems of interface delamination, foam collapse and structural deformation defects caused by the difference in thermal expansion coefficient of PBO fiber / epoxy resin prepreg, metal parts and filling foam material during the high temperature and high pressure curing process of black box composite material structural parts in the field of aviation, and the uneven distribution of temperature-pressure field caused by the co-curing of multiple materials in the traditional curing process. The curing method of the present application does not affect the performance of the matching filling foam material, and obtains a composite material with stable and excellent performance.
[0009] In order to solve the above technical problems, one of the objects of the present application is to provide a black box composite material curing method, the specific steps are as follows:
[0010] S1: Place the laid-up black box preform into a vacuum bag, use a vacuum pump to reduce the pressure in the vacuum bag to below 0.1 MPa, and remove the air and moisture in the vacuum bag to avoid bubbles and defects during the curing process;
[0011] S2: Move the black box preform after the S1 assembly and bagging treatment to a hot press tank for pre-curing, increase the temperature to 80-120℃ at a rate of 1-3℃ / min, and simultaneously apply a pressure of 0.5-3.0 MPa, and pre-cure for 1-3 hours to preliminarily crosslink the resin matrix and enhance the initial strength of the black box composite material;
[0012] S3: Hot press curing, after pre-curing, increase the temperature to 150-180℃ at a rate of 1-3℃ / min, and adjust the curing pressure to 0.2-0.6 MPa;
[0013] S4: Holding, keep the temperature at 150-180℃ and the pressure at 0.2-0.6 MPa for 4-10 hours to ensure that the resin matrix is fully crosslinked and cured to form a stable composite material structure;
[0014] S5: After cooling, reduce the temperature to below 60℃ at a rate of 1-3℃ / min, slowly release the pressure to normal pressure, and take out the tank to ensure the stability of the performance of the composite material.
[0015] Further, the S1 black box preform laying specific steps are as follows:
[0016] (1) Select high modulus PBO fiber, the glass transition temperature of epoxy resin is greater than 180℃, and lay up alternately in the order of 0° and 90° to achieve the required skin thickness of the black box;
[0017] (2) Use a steel mold, and apply release agent after cleaning the surface of the mold before laying up the composite material.
[0018] Furthermore, the S2 pre-curing condition is preferably: raising the temperature to 100° C. at a heating rate of 1-3° C. / min, and simultaneously applying a pressure of 0.5-1.0 MPa, and performing the pre-curing treatment for 1 hour.
[0019] Furthermore, the S3 pressurized curing condition is preferably to continue heating, raising the temperature to 150-180° C. at a heating rate of 2-3° C. / min, and adjusting the curing pressure to 0.5 MPa.
[0020] Furthermore, the S3 sets a circulating gas system in the autoclave to ensure the temperature uniformity of each part of the composite material during the curing process and control the temperature deviation within ±3°C.
[0021] Furthermore, the S4 heat preservation condition is preferably to control the temperature at 150-180° C., adjust the curing pressure to 0.5 MPa, and maintain the temperature and pressure for 5 hours.
[0022] The above one or more technical solutions of the present invention have at least one or more of the following technical effects:
[0023] Through the multi-material collaborative curing method, the resin fluidity and interface bonding strength are improved to avoid stress concentration between metal parts and composite materials; ensure that the filling foam material does not deform or collapse during the entire curing process (especially the high-temperature stage), and solve the problem of matching the curing system when co-curing heterogeneous materials; enhance the overall impact resistance and high-temperature resistance of the black box structure.
[0024] The present method for curing black box composite materials can effectively improve composite material performance and product reliability, and has promising application prospects. Through curing methods such as a staged temperature control process and a vacuum negative pressure process, the strength, hardness, heat resistance, and corrosion resistance of the black box shell material are significantly enhanced. In actual production, process parameters can be appropriately adjusted according to specific needs and production conditions to achieve optimal product performance and production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 : Black box shell component curing flow chart. Specific implementation plan
[0026] The present invention aims to provide an efficient and stable method for curing black box composite materials, thereby improving the performance and reliability of the black box housing. To achieve this objective, the present invention employs a technical solution: vacuum-bagging a preform of the black box composite material and then transferring it to an autoclave. Curing of the black box composite material is achieved through a phased temperature control process and vacuum negative pressure process.
[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application and the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.
[0028] The present application is a black box composite material curing method, and the curing process is as follows:
[0029] (1) Place the laid-up black box preform into a vacuum bag, use a vacuum pump to reduce the pressure in the vacuum bag to below 0.1 MPa, and remove the air and moisture in the vacuum bag to avoid air bubbles and defects in the curing process. After assembling the bag, move the black box product to a hot press tank for curing.
[0030] (2) Increase the temperature to 80-120℃ at a rate of 1-3℃ / min, and at the same time, apply a pressure of 0.5-3.0 MPa, and perform a pre-curing treatment for 1-3 hours to preliminarily cross-link the resin matrix and enhance the initial strength of the black box composite material.
[0031] (3) After the pre-curing treatment is completed, increase the temperature to 150-180℃ at a rate of 1-3℃ / min, and adjust the curing pressure to 0.2-0.6 MPa. Set up a circulating gas system in the hot press tank to ensure the uniformity of the temperature of each part of the composite material during the curing process, and control the temperature deviation within ±3℃. Slow heating rate allows the resin matrix to be heated uniformly, avoiding material deformation or defects caused by excessive temperature gradient. Appropriate pressure can promote the flow and infiltration of the resin matrix, allowing the carbon fibers to fully combine with the resin.
[0032] (4) Maintain at 150-180℃ and 0.2-0.6 MPa for 4-10 hours to ensure that the resin matrix is fully cross-linked and cured to form a stable composite material structure.
[0033] (5) Reduce the temperature to below 60℃ at a rate of 1-3℃ / min, and slowly release the pressure to normal pressure to remove the tank. Slow cooling and pressure release process can effectively reduce the generation of residual stress, ensuring the stability of the performance of the composite material.
[0034] The technical solutions of the present application will be described in detail below with reference to examples.
[0035] (1) Select high modulus PBO fibers, and the glass transition temperature of the epoxy resin is greater than 180℃. Alternate laying according to the order of 0° and 90° to achieve the required skin thickness of the black box.
[0036] (2) Use a steel mold, and apply release agent after cleaning the surface of the mold before laying the composite material.
[0037] (3) Put the completed black box product and mold into a vacuum bag, and vacuumize to below 0.1 Mpa;
[0038] (4) Put into a hot press tank, and heat to 80-100℃ at a heating rate of 1-3℃ / min, and at the same time, apply a pressure of 0.5-3.0 Mpa, and perform a pre-curing treatment for 1 h.
[0039] (5) After the pre-curing is completed, continue to heat, and increase the temperature to 150-180℃ at a heating rate of 2-3℃ / min, adjust the curing pressure to 0.2-0.6 Mpa, and keep the temperature and pressure for 4-10 hours;
[0040] (6) After the curing is completed, start to decrease the temperature at a temperature decreasing rate of 2℃ / min, until the temperature is below 60℃, and start to release the pressure and take out the tank.
[0041] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application belong to the scope of the claims of the present application and the equivalent technologies thereof, the present application also intends to include these modifications and variations.
[0042] The present application has been applied to the manufacturing of a throw-away type black box shell and cover plate components, and the scheme is feasible.
Claims
1. A black box composite material curing method, characterized in that: The specific steps are as follows: S1: Place the laid-up black box preform into a vacuum bag and reduce the pressure inside the vacuum bag to below 0.1 MPa to remove air and moisture from the bag to avoid bubbles and defects during the curing process. S2: The black box preforms after the bagging treatment in S1 are moved to an autoclave for pre-curing. The temperature is raised to 80-120°C at a heating rate of 1-3°C / min, and a pressure of 0.5-3.0 MPa is applied at the same time for pre-curing for 1-3 hours to initially cross-link the resin matrix and enhance the initial strength of the black box composite material. S3: Hot pressing curing: After the pre-curing treatment is completed, the temperature is increased to 150-180°C at a heating rate of 1-3°C / min, and the curing pressure is adjusted to 0.2-0.6Mpa; S4: Keep warm at 150-180℃ and 0.2-0.6Mpa for 4-10 hours to ensure that the resin matrix is fully cross-linked and cured to form a stable composite material structure; S5: Post-cooling treatment: reduce the temperature to below 60°C at a cooling rate of 1-3°C / min, and slowly release the pressure to normal pressure before unloading from the tank to ensure the stability of the performance of the composite material.
2. The black box composite material curing method according to claim 1, characterized in that: The specific steps of the S1 black box preform layup are: (1) Use high modulus PBO fiber and epoxy resin with a glass transition temperature greater than 180°C, and alternately lay them up in the order of 0° and 90° to achieve the skin thickness required by the black box; (2) Use a steel mold and apply a release agent after cleaning the mold surface before laying the composite material.
3. The black box composite material curing method according to claim 1, characterized in that: The S2 pre-curing conditions are preferably: raising the temperature to 80-100° C. at a heating rate of 1-3° C. / min, and simultaneously applying a pressure of 0.5-1.0 MPa, and performing the pre-curing treatment for 1 hour.
4. The black box composite material curing method according to claim 1, characterized in that: The S3 pressurized curing condition is preferably to continue heating, raising the temperature to 150-180° C. at a heating rate of 2-3° C. / min, and adjusting the curing pressure to 0.5 MPa.
5. The black box composite material curing method according to any one of claims 1 or 4, characterized in that: The S3 is provided with a circulating gas system in the autoclave to ensure the temperature uniformity of each part of the composite material during the curing process and to control the temperature deviation within ±3°C.
6. The black box composite material curing method according to claim 1, characterized in that: The S4 heat preservation condition is preferably to control the temperature at 150-180° C., adjust the curing pressure to 0.5 MPa, and maintain the temperature and pressure for 5 hours.