Method for realizing large-size slender thin-wall I-shaped beam structure composite part through open air bag

Abstract

The invention discloses a method for realizing a large-size slender thin-wall (3m or above) I-shaped beam structure composite part through an open air bag. The fiber reinforced rubber end open type air bag is formed through a metal mold, and the formed air bag is used as a part of a forming mold of the large-size slender I-shaped beam structure composite part to complete the forming process of theI-shaped beam structure composite part. Compared with a traditional core mold forming method, the method has the advantages that the air bag can uniformly and accurately transfer pressure applied bya hot pressing tank, the phenomenon that due to the fact that the composite part is large in size and is of a thin-wall structure, the thickness is out of tolerance and the molded surface is out of tolerance are avoided, the percent of pass and the efficiency of production are improved, the precision of the molded surface, the size and the thickness after the part is formed are guaranteed, meanwhile, the air bag can be repeatedly used, and can be re-manufactured according to needs, the manufacturing cost is low, the production period is short, and the manufacturing success rate is high.

Description

technical field [0001] The invention belongs to the technical field of advanced composite material manufacturing, and in particular relates to the manufacturing of high-performance carbon fiber composite structural parts in the industry of aircraft, spacecraft and automobiles. Background technique [0002] Resin-based carbon fiber composite materials have superior properties such as specific strength and specific stiffness, strong designability, good fatigue fracture resistance, corrosion resistance, and good dimensional stability. They are currently widely used in aviation, aerospace, transportation and other fields. High-performance structural materials. Among various carbon fiber composite molding processes, the autoclave process has uniform molding temperature and pressure, and has good adaptability to parts of different materials, shapes, sizes and structures. One of the main process methods of material components. [0003] I-beams are relatively common reinforced str...

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Problems solved by technology

[0007] The disadvantages of using the mandrel method to form I-beams mainly include the following four aspects: (1) Since the mandrel itself has a certain rigidity, and the metal mandrel must be accurately positioned through the hole pin, it is difficult to conduct external pressure through the mandrel. To be uniform and accurate, it is easy to cause the thickness of the composite material to be out of tolerance and internal quality defects; (2) Since the core mold has a certain thickness and the thickness is not uniform, according to the heat transfer effect, the heating rate of different regions of the product will be different , thereby affecting the internal molding quality of the part, resulting in a large amount of deformation after the part is cooled and demolded; (3) In the case of a large part size, the overall length of the metal mandrel is also large, and during use It is easy to deform and affect the contour of the product after molding; (4) Since the mandrel is made of metal, it has a large weight and is very inconvenient to operate. The positioning benchmark must have high precision requirements for the mold, so the manufacturing and maintenance costs of the metal mandrel are relatively high, and the manufacturing cycle for repair or reprocessing is relatively long

[0008] However, using the airbag method to form the I-beam can ensure the uniform transfer of external pressure and heat, but the manufacturing process of the airbag itself is relatively complicated, and the airbag is prone to cracking or damage near the air nozzle, and the manufacturing pass rate is low; Airbags have strict airtightness requirements, and once an air leak occurs, it is usually impossible to repair, which leads to a reduction in the service life and reliability of the airbag, which is especially evident in the molding process of large-scale composite parts

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