RTM process is the main principle of laying in the cavity in accordance with the requirements of performance and structure design of reinforced material into the form, injection equipment will use special resin system closed cavity, and fastening and injection mould with peripheral seal and exhaust system, to ensure that the resin flow smooth out all the gas in the cavity side by side and infiltrating fiber thoroughly, also have heating system, pressure system, A forming process for a composite component that can be heated and cured. It is a forming method that does not use prepreg or autoclave. Therefore, with high efficiency, investment, green and other advantages, is the future of a new generation of aircraft airframe manufacturing technology has the potential for development.

  Resin transfer molding is a low cost method for composite manufacturing. Initially, it was mainly used in aircraft secondary load-bearing structures, such as cabin doors and inspection covers. In 1996, the Defense Advance Research Agency (PDA) of the United States carried out research on low-cost RTM manufacturing technology for high strength main-bearing components. At present, the manufacture of small and medium-sized composite RTM parts has been widely used, and the large RTM parts have been successfully used in the vertical tail of JSF. Resin transfer molding is a low-cost composite fabrication method originally used for aircraft secondary load-bearing structures such as cabin doors and inspection covers. In 1996, the Defense Advance Research Agency (PDA) of the United States carried out research on low-cost RTM manufacturing technology for high strength main-bearing components. At present, the manufacture of small and medium-sized composite RTM parts has been widely used, and the large RTM parts have been successfully used in the vertical tail of JSF. The advantages of this method are environmental protection, the formation of laminates with good performance and good double-sided quality, in the aviation application can not only reduce its own labor, but also because it can form a large integral part, so that the assembly workload is reduced. However, the parts formed by pressure injection of resin into the mold cavity have some defects, such as large porosity content, low fiber content, uneven distribution of resin in the fiber, and insufficient impregnation of resin to the fiber, so this technology still has the potential for improvement.

  Equipment for RTM process is called "integration of RTM molding equipment", in fact this is not only a device, accurate should be a set of equipment, including: the reaction kettle, vacuum equipment, exhaust system, heating system, pressure injection system, mold and other equipment, the system is the organic fusion of the equipment in accordance with the RTM process.

  At present, in addition to the overseas production of such equipment, only Bairuo Instrument in China is capable of producing RTM integrated forming equipment with a pressure holding capacity of 200 tons, breaking the situation that imported equipment dominates the world. The equipment integrates the functions of upper and lower die moving, turning over, mold closing, mold closing and turning over, mold heating, pressure holding and injection, etc. It has the characteristics of simple operation, temperature control and pressure holding. It meets the requirements of RTM forming process and meets the requirements of RTM production automation in composite material production enterprises. At present, the main production of RTM equipment: aircraft doors, tail fins, propellers, etc.

The advantages of using RTM process are:

  The intervention molds and resin materials used in the resin transfer molding process are cheaper than prepregs, can be stored at room temperature, and the molding process has fewer volatile components and less environmental pollution. This process can be used to produce thicker, net - formed parts, while eliminating many subsequent processing procedures. The process also helps in the production of complex parts with precise dimensions and highly finished surfaces.

Another feature of the resin transfer molding process is that it allows a mandrel filler to be placed in the preform before the die is closed to avoid extrusion of the preform during the die closing process. The proportion of the mandrel in the whole preform is low, about 0-2%. The anisotropic body with high strength, low density and small deformation can be produced by this process.

  In short, the resin transfer molding process (RTM) can be used as a highly efficient and repeatable automated manufacturing process to dramatically reduce the processing and molding time from days to hours or even tens of minutes for traditional hand-and-paste molding.