阅读说明：本技术 一种基于充液成形的纤维金属层板制备成形一体化工艺 (Integrated process for preparing and forming fiber metal laminate based on liquid filling forming ) 是由 郎利辉 李磊 于 2019-11-22 设计创作，主要内容包括：一种基于充液成形的纤维金属层板制备成形一体化工艺是将充液成形技术与热成形技术进行交叉、融合而衍生出的一种新型纤维金属层板制备成形固化一体化技术,兼具充液成形与热成形的特点,可以一次性完成成形与固化两步工艺,适用于热固性和热塑性两种纤维金属层板。定义为：凸模预先冷却,压边圈合模,液室预充液。首先进行加热油液至指定温度,然后进行预胀工序,使层板紧贴凸模。随后凸模下行,液室压力按指定压力加载,完成成形。充液成形后,根据不同纤维金属层板特点,加热或冷却液室液压油,改变固化温度和压力条件,完成固化工艺,从而获得最终的产品零件。模具一次安装完成,实现成形和固化两套制备工序过程,减少了转换模具的耗时,保证了产品零件的整体成形精度要求和外观尺寸精度要求。同时,充液成形模具安装方便,易于更换,降低了修模时间,提高了生产效率。该一体化工艺技术在成形航空航天、汽车等领域的复杂纤维金属层板结构件方面具有独特的优势,具有广阔的应用前景。(A preparation, forming and curing integrated process of a fiber metal laminate based on liquid filling forming is a novel fiber metal laminate preparation, forming and curing integrated technology derived by crossing and fusing a liquid filling forming technology and a hot forming technology, has the characteristics of liquid filling forming and hot forming, can complete a forming and curing two-step process at one time, and is suitable for two fiber metal laminates of thermosetting and thermoplastic. Is defined as: the male die is cooled in advance, the clamping ring is closed, and liquid is filled in the liquid chamber in advance. Firstly, heating oil liquid to a specified temperature, and then carrying out a pre-expansion process to enable the laminate to be tightly attached to the male die. And then the male die descends, and the pressure of the liquid chamber is loaded according to the specified pressure, so that the forming is completed. After liquid filling forming, according to the characteristics of different fiber metal laminate plates, heating or cooling hydraulic oil in a liquid chamber, changing the curing temperature and pressure conditions, and completing the curing process, thereby obtaining the final product part. The die is mounted at one time, two sets of preparation processes of forming and curing are realized, the time consumption for converting the die is reduced, and the integral forming precision requirement and the appearance size precision requirement of a product part are ensured. Meanwhile, the liquid filling forming die is convenient to install and easy to replace, the die repairing time is reduced, and the production efficiency is improved. The integrated process technology has unique advantages in the aspect of forming complex fiber metal laminate structural members in the fields of aerospace, automobiles and the like, and has wide application prospects.)

1. A preparation and forming integrated process of a fiber metal laminate based on liquid filling forming is characterized in that: the preparation and forming integrated process of the fiber metal laminate based on liquid filling forming comprises the following steps in sequence:

1) and placing the thermosetting or thermoplastic fiber metal laminate on the integrated lower die for liquid-filling forming preparation and curing. And finishing the process steps of liquid chamber liquid supplementing, edge pressing and the like, and adding cooling liquid to cool the male die.

2) The liquid and the fiber metal laminate are heated by the heating pipe to reach the specified temperature. The heat transfer between the warm medium and the fiber metal laminate makes the fiber metal laminate layers and the interface in the optimal forming state. The fiber metal laminate is subjected to a passive liquid-filling forming pre-expansion process, and proper counter-expansion pressure is preset, so that the forming performance of the fiber metal laminate is further improved.

3) And in the forming stage, the cooling male die descends at a set running speed, and the blank holder adjusts the blank holder force at the same time, so that the fiber metal laminate is better promoted to flow into the cavity of the female die. The heating pipe controls the temperature of the forming medium, the pressure of the liquid chamber is loaded according to an optimized loading path, the layering phenomenon of the fiber metal laminate in the forming process is avoided, and the forming of the fiber metal laminate is finally completed.

4) And (3) entering a curing stage, wherein the integrated die respectively selects a heating or cooling process according to the thermosetting or thermoplastic fiber metal laminate, and the curing process is finished on the die without removing the part from the die for secondary curing.

5) And (5) recovering the temperature of the die, unloading the fluid pressure, opening the die, taking out the part, and finishing the processing.

2. The integrated hydroforming-based fiber metal laminate manufacturing process according to claim 1, wherein: the process has the advantages of both liquid-filling forming and hot forming to form the fiber metal laminate. Firstly, the advantages of improving the forming limit of the fiber metal laminate, controlling the lamination phenomenon of the laminate, uniform wall thickness distribution and small resilience amount are achieved by utilizing the hydroforming, and the fiber metal laminate member with a complex structure is obtained.

3. The integrated hydroforming-based fiber metal laminate manufacturing process according to claim 1, wherein: by utilizing the characteristics of excellent plasticity and deformation fluidity of the resin at high temperature, the forming performance can be further improved, and the curing process can be directly completed on a die by controlling the temperature after forming, thereby greatly shortening the preparation time.

4. The integrated hydroforming-based fiber metal laminate manufacturing process according to claim 1, wherein: the liquid chamber pressure can be loaded to be far larger than the normal pressure of the autoclave process, so that excellent interlayer performance is obtained, and springback generation is further controlled.

5. The integrated hydroforming-based fiber metal laminate manufacturing process according to claim 1, wherein: in the process of liquid filling and forming, a female die is omitted, so that the investment of equipment is reduced, and the production cost of the fiber metal laminate part is further reduced.

Technical Field

The invention belongs to the field of composite laminate preparation and forming.

Background

Fiber metal laminates (FMLs for short) are a hybrid structure material which is formed by layering metal sheets (aluminum alloy and titanium alloy) and Fiber (aramid Fiber, glass Fiber and carbon Fiber) reinforced resin matrix composite materials according to specific requirements and then curing at a certain temperature and under a certain pressure. Hybrid materials in the form of FMLs produce synergistic effects, providing better fatigue resistance, damage tolerance, mechanical/thermal properties. FMLs can be classified into thermosetting FMLs and thermoplastic FMLs depending on the resin matrix material. The thermosetting resin is characterized in that after the curing process is finished, the resin form is irreversible, while the thermoplastic resin is softened and hardened by cooling when being heated, and the process is reversible, so that the preparation and forming processes of the two laminates are completely different, and the preparation and forming equipment is not universal.

The common preparation and forming methods for thermosetting FMLs comprise a self-forming technology, roll bending forming, autoclave forming and the like, and are characterized in that FMLs are subjected to normal-temperature layering and then are subjected to forming and curing, and qualified parts can be prepared only after curing is carried out for a period of time at a certain temperature and under a certain pressure. The method has long preparation and forming time, needs further curing in a vacuum bag or an autoclave after forming, has various process steps, and can only form parts with smaller curvature. The common preparation and forming method for thermoplastic FMLs is a hot press forming technology, because thermoplastic resin is mostly in a solid state at normal temperature, the thermoplastic FMLs can be prepared only by heating and pressurizing after layering, a laminate needs to be heated before a forming process, so that the resin is in a viscous state, a required part is formed, and then the required part is quickly placed in a low-temperature medium to be solidified again. Thermoplastic FMLs are shaped with a faster cure rate than thermoset FMLs, but require a lower temperature environment or medium.

The domestic Langli topic group provides a fiber metal laminate hydro-forming process, and a thermosetting fiber metal laminate is formed by a semi-curing hydro-forming process (namely, hydro-forming uncured full FMLs are utilized), so that the forming limit of the fiber metal laminate is further improved, and the resilience and the layering phenomenon are reduced. However, fiber metal laminates formed by this process still require further curing in a vacuum bag to produce the final part, and such processes and equipment are not capable of forming thermoplastic FMLs. Therefore, in order to further improve the formability of the fiber metal and expand the application range of the fiber metal laminate formed by the liquid-filling forming process, a liquid-filling forming-based fiber metal laminate preparation and forming integrated process, namely a composite forming preparation process combining liquid-filling forming and warm-hot forming technologies, is provided.

Disclosure of Invention

In order to solve the above problems, the present invention aims to provide a combined process integrating forming and curing, which completes two process steps of preparing and forming a fiber metal laminate on a set of equipment, thereby improving production efficiency. Secondly, based on the process and the equipment, the thermoplastic fiber metal laminate and the thermosetting fiber metal laminate can be formed, and the process flexibility is improved. Thirdly, due to the addition of the temperature control technology, the resin state during forming is further controlled, more process parameter choices are provided, and a process window is expanded for forming qualified parts.

In order to achieve the purpose, the preparation and forming integrated process of the fiber metal laminate based on liquid-filling forming sequentially comprises the following steps:

1) the thermosetting or thermoplastic fiber metal laminate is placed on a concave die (lower die) of a liquid-filling forming preparation and curing integrated die. And finishing the process steps of liquid chamber liquid supplementing, edge pressing and the like, and adding cooling liquid to cool the male die (the upper die).

2) The liquid and the fiber metal laminate are heated by the heating pipe to reach the specified temperature. The heat transfer between the warm medium and the fiber metal laminate makes the fiber metal laminate layers and the interface in the optimal forming state. The fiber metal laminate is subjected to a pre-expansion process, and a proper pre-expansion pressure is preset, so that the forming performance of the fiber metal laminate is further improved.

3) And in the forming stage, the male die descends at a set running speed, and the blank holder adjusts the blank holder force at the same time so as to better promote the fiber metal laminate to flow into the cavity of the female die. The heating pipe controls the temperature of the forming medium, the pressure of the liquid chamber is loaded according to an optimized loading path, the layering phenomenon of the fiber metal laminate in the forming process is avoided, and the forming of the fiber metal laminate is finally completed.

4) And (3) entering a curing stage, wherein the integrated die respectively selects a heating or cooling process according to the thermosetting or thermoplastic fiber metal laminate, and the curing process is finished on the die without removing the part from the die for secondary curing.

5) And (5) recovering the temperature of the die, unloading the fluid pressure, opening the die, taking out the part, and finishing the processing.

The invention provides a preparation and forming integrated process of a fiber metal laminate based on liquid filling forming, which is a novel fiber metal laminate forming and curing integrated technology derived by crossing and fusing a liquid filling forming technology and a hot forming technology. The technology aims at the defects that the application of composite materials is gradually increased in the fields of aerospace, automobiles, national defense industry and the like, the production efficiency of composite material structural parts is further improved, the product quality is difficult to meet practical requirements and the like, and a hot medium forming and curing process, namely a composite forming and curing mixed process, is developed. The process has the advantages of both liquid-filling forming and hot forming. Firstly, the advantages of improving the forming limit of the fiber metal laminate, controlling the lamination phenomenon of the laminate, uniform wall thickness distribution and small resilience amount are achieved by utilizing the hydroforming, and the fiber metal laminate member with the complex structure is obtained. Secondly, by utilizing the characteristics of excellent plasticity and deformation fluidity of the resin at high temperature, the forming performance can be further improved, the curing process can be directly completed on a die through temperature control after forming, the preparation time is greatly shortened, the normal pressure which is far greater than that of the autoclave process can be loaded through the pressure of a liquid chamber, the excellent interlayer performance is further obtained, and the generation of springback is further controlled.

The fiber metal laminate preparation, forming and integrated forming equipment provided by the invention can fully realize the preparation, forming and curing integrated process. Firstly, a fiber metal laminate complex structural member is obtained by utilizing a heat medium liquid filling forming process, and the curing process is directly finished on a liquid filling forming die by further controlling the pressure and temperature coupling action of a liquid chamber to prepare a final part. The process of re-solidifying the part after moving out of the die is omitted, the production efficiency is improved, and the production cost is reduced. Meanwhile, a concave die is omitted in the liquid filling forming process, so that the investment of equipment is reduced, and the production cost is further reduced.

Drawings

FIG. 1 is a schematic view of a forming integrated process for preparing a fiber metal laminate based on liquid-filling forming according to the invention.

FIG. 2 is a schematic diagram of the anti-swelling stage of a fiber metal laminate preparation and forming integrated process based on hydro-forming provided by the invention.

FIG. 3 is a schematic diagram of the forming and solidifying stages of a fiber metal laminate preparing and forming integrated process based on liquid-filling forming provided by the invention.

In the figure: 1-male die (upper die), 2-male die cooling pipe, 3-blank holder, 4-sealing ring, 5-female die (lower die), 6-cold oil inlet, 7-pressure cylinder inlet, 8-female die liquid chamber, 9-oil outlet, 10-fiber metal laminate and 11-heating pipe.

Detailed Description

The invention provides a process for preparing and forming integrated fiber metal laminate based on liquid-filling forming, which is described in detail in the following with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1-3, the present invention provides a process for preparing and forming integrated fiber metal laminate based on liquid-filled forming, which comprises the following steps in sequence:

1) the fiber metal laminate 10 (either thermoplastic or thermoset) is placed on the hydroformed cured integral lower mold 5. At the moment, liquid is filled in advance through the oil filling port 7, oil rises to the position below the plate and contacts with the plate, the heating pipe 11 is not heated at the moment, and the temperature and the pressure value are both 0. At the moment, the blank holder 3 moves downwards, a preset blank holder force F is applied, and the speed of the fiber metal laminate flowing into the lower die is controlled through different blank holder forces F. The O-shaped sealing ring 4 is arranged on the lower die to prevent oil from overflowing during forming, so that the liquid pressure is maintained. Meanwhile, cooling liquid is introduced into the cooling pipeline 2 in the male die 1, so that the temperature of the male die is reduced, and the forming performance of the fiber metal laminate is further improved.

2) Firstly, the liquid and the fiber metal laminate are heated by the heating pipe 11 to reach the specified temperature. The temperature at which the thermoset fiber metal laminate 10 is heated is generally below the cure temperature and the temperature at which the thermoplastic fiber metal laminate 10 is heated is generally above the glass transition temperature, with the contact of the warm media with the fiber metal laminate providing the optimum formation of the fiber metal laminate layers and interfaces, as shown in fig. 2. Meanwhile, in order to further enhance the forming performance of the fiber metal laminate, a passive liquid filling forming pre-expansion process is adopted. Hydraulic oil is injected through the oil injection port 7 of the supercharger, so that the pressure of the liquid chamber reaches a preset value P, the pressure of the liquid chamber is called as pre-expansion pressure, the fiber metal laminate can be better coated on the male die 1, the laminate is fully contacted with the male die before the male die 1 descends, and the forming performance is further improved.

3) As shown in fig. 3, the male die 1 which is always cooled by the cooling liquid descends under the surrounding of the warm medium according to the set running speed, and the pressure of the edge pressing ring can be adjusted in real time in the descending process of the male die, so that the flow of the fiber metal laminate into the cavity of the female die is better promoted. Meanwhile, the pressure in the liquid chamber 8 is loaded according to the optimized liquid chamber pressure loading path, so that the layering phenomenon of the fiber metal laminate in the forming process is avoided, and meanwhile, the forming performance of the aluminum alloy can be further improved due to the three-dimensional stress state. And under the combined action of the liquid chamber pressure and the downward force of the male die, the forming of the fiber metal laminate is completed. Meanwhile, the forming performance of the laminate is further improved due to the action of the warm medium.

4) After the thermosetting fiber metal laminate is formed, a cooling pipe of the male die 1 is filled with liquid with the same temperature as that of a liquid chamber, and heating of the heating pipe 11 is controlled through a thermocouple and a temperature control device to keep the laminate in a curing temperature range. And the oil filling ports 6, 7 and the oil outlet 9 are closed, so that the pressure of the liquid chamber is at a preset stable level, the generation of a gap in the curing process is prevented, and the rebound is reduced. And finally cooling to room temperature according to the curing temperature control curve, unloading the fluid pressure after curing is finished, retreating the male die 1, retreating the blank holder 3, taking out the part, and finishing processing.

5) For thermoplastic fiber metal laminates, the male mold is kept cool after forming. Meanwhile, the heating pipe 11 is closed, low-temperature hydraulic oil is injected into the liquid chamber through the cooling oil pipe 6, meanwhile, the oil outlet 9 is decompressed at the same speed, the fiber metal laminate is rapidly cooled while the pressure of the liquid chamber is maintained, the thermoplastic resin is rapidly solidified, the layering phenomenon is prevented, and the rebound is reduced. And after solidification is finished, fluid pressure is unloaded, the male die 1 retreats, the blank holder 3 retreats, the part is taken out, and machining is finished.