Method for molding resin matrix composite material by zero-adhesive-discharge vacuum assisted resin infusion (VARI)

Abstract

The invention belongs to a resin matrix composite material liquid molding technology, and relates to a method for molding a resin matrix composite material by zero-adhesive-discharge vacuum assisted resin infusion (VARI). A glue inlet diversion net (20) and a resin drawing layer (30) are arranged on a fiber-reinforced premolded body (3); the outer surface of the fiber-reinforced premolded body (3) is covered with a micro-ventilation layer (4) and a glue blocking layer (5). According to the method, a resin glue discharge channel is omitted, so that zero adhesive discharge of the VARI molding technology is realized, and the using amount of resin is accurately controlled; the micro-ventilation layer (4) and the glue blocking layer (5) are additionally arranged, so that pressure is evenly transmitted into the fiber-reinforced premolded body (3); furthermore, the excessive gas in the resin and the fiber-reinforced premolded body (3) can be fully discharged, so that the porosity of parts can be reduced, the molding quality and the thickness uniformity of the parts can be improved, and the production cost is remarkably lowered.

Description

technical field [0001] The invention belongs to the liquid molding technology of resin-based composite materials, and relates to a method for resin-based composite material formed by vacuum-assisted resin infiltration with zero glue out. Background technique [0002] Vacuum Assisted Resin Infusion (VARI for short) is a liquid molding manufacturing technology suitable for the integral molding of large composite components. Since the entire process only needs a vacuum of -0.1Mpa, it can be processed in an oven. Complete resin infiltration and curing, no need for a huge investment in autoclave, and can combine stitching, weaving and other technologies to achieve three-dimensional reinforcement of composite components, with the advantages of low manufacturing cost, high molding efficiency, low porosity and good integrity . However, the conventional VARI molding process has the following disadvantages: (1) The conventional VARI process needs to set up one or more resin outlet ch...

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Problems solved by technology

However, the conventional VARI molding process has the following disadvantages: (1) The conventional VARI process needs to set up one or more resin outlet channels for resin diversion, and the resin flowing out through the resin outlet channels cannot be recycled and used, resulting in waste of cost; (2) Affected by the inconsistency of the resin flow rate and flow path length of each resin outlet channel, the amount of resin output cannot be accurately calculated, resulting in the need to prepare excess resin when conventional VARI molding composite parts, resulting in a large amount of resin waste, improving (3) The pressure transmission of the conventional VARI molding process depends on the pressure difference between the inlet and outlet channels. As the resin penetrates the preform, the pressure gradient becomes smaller and smaller. On composite parts There will be a phenomenon that the glue content near the glue inlet is high (that is, the thickness is too thick), and the glue content near the glue outlet is low (that is, the thickness is too thin), and the thickness uniformity of composite parts is not ideal.

But at the same time, the micro-breathable PTFE composite cloth also has the following disadvantages: (1) The micro-breathable PTFE composite cloth is heat-stretched, and due to the limitation of the process, the uniformity of the pore size and density of the formed micro-pores cannot be guaranteed; Tests have shown that micro-breathable polytetrafluoroethylene composite cloth can only protect liquids with a viscosity above 150cp, but cannot protect liquids with a viscosity below 150cp; and generally suitable for high-temperature curing resins for VARI molding, such as BA9914 of AVIC Composite Materials Co., Ltd. , Hexcel's RTM6, Cytec's cycom890, the working viscosity is ≤100cp, only a few medium-temperature curing resins suitable for VARI molding, the working viscosity is >150cp, and the micro-breathable PTFE compound can be directly used in the resin transfer process Cloth is used as a micro-breathable layer, such as BA9912 of Beijing Aeronautical Manufacturing Engineering Research Institute, so the use of micro-breathable PTFE composite cloth as a micro-breathable layer in the vacuum-assisted resin infiltration molding process has great limitations; (2) During the curing process of the resin, its viscosity will further decrease with the increase of temperature

Therefore, it is difficult to protect the low-viscosity resin by directly using micro-breathable polytetrafluoroethylene composite cloth as the micro-breathable layer in the VARI molding composite material process, and resin leakage will occur, which will directly lead to the failure of VARI molding composite parts; ( 3) The thickness of the polytetrafluoroethylene functional layer is a few tenths of a millimeter, which is not resistant to scratches and has poor ductility. In areas with complex structures, the phenomenon of "bridging" is prone to occur, resulting in a micro-breathable polytetrafluoroethylene composite cloth functional layer. Cracks to disable the function of its protective resin

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