Forming method for variable cross-section hollow-structure composite part with high-precision inner surface

Abstract

The invention relates to the technical field of forming of resin-based fiber reinforced composite prepreg through an autoclave, in particular to a forming method for a variable cross-section hollow-structure composite part with a high-precision inner surface. A forming mandrel is adopted and comprises a sold mold and a water-soluble core, and the water-soluble core is located in the spaced formedby the soft mold. The forming method includes the following steps that composite prepreg is paved on the surface of the soft mold; the composite prepreg is cured; and the water-soluble core is removed, and the soft mold and the cured composite are separated. The forming method provided by the invention adopts the forming mandrel combining the soft mold and the water-soluble core, the soft mold isused for being attached to the composite, and therefore high surface quality can be provided. The water-soluble core is used for supporting the soft mold, so that the soft mold has a preset shape, andthe cost of the forming mandrel is low. In the machining process of the composite part, during demolding, the water-soluble core is removed firstly, the soft mold is deformed and removed, and therefore demolding is achieved, and demolding operation is simple.

Description

technical field [0001] The invention relates to the technical field of resin-based fiber-reinforced composite material prepreg autoclave forming technology, in particular to a high-precision internal surface variable cross-section hollow structure composite material part forming method. Background technique [0002] Due to its light weight, high specific strength and specific stiffness, and strong designability, composite materials are increasingly used in the field of aerospace vehicle structural parts; Aero-engine inlet with deformed cross-section; when forming this type of structural parts, the side with high surface quality and precision requirements is usually selected as the surface that fits the mold, referred to as the mold-fitting surface. When the inner shape surface of the part is the mold-fitting surface, the male mold lay-up and molding method can be used, and the demolding of the part after curing is more difficult. In order to achieve the purpose of forming p...

AI Technical Summary

Problems solved by technology

[0003] 1) The metal combined mandrel has many assembly relationships, high precision of the mating surface, difficult processing, high cost, and cannot guarantee the overall airtightness of the mold, and problems such as vacuum leakage are prone to occur during the curing process; when the shape is relatively When it is complex, metal combined mold processing cannot be realized;

[0004] 2) Water-soluble mandrel: There are two types of water-soluble mandrels, one is pouring mandrel, that is, the mandrel is obtained by pouring special water-soluble materials in the cavity and solidified, the internal quality and external quality of this kind of mandrel High requirements, no holes, expensive materials, high manufacturing cost of the mandrel; another mandrel is poured into a cube or cylinder in the cavity, and then the mandrel surface is obtained by CNC machining. The internal quality and The external quality requirements are high, there must be no holes, and the material is required to be cut, the same material is expensive, and the manufacturing cost of the mandrel is high

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