Two RTM Processes Suitable for Large, High-performance Composites Are:

Resin Transfer Molding (RTM) is a typical liquid molding process for fiber-reinforced resin matrix composites. The process mainly involves:

1. Designing a fiber preform according to the shape and mechanical property requirements of the desired part.

2. Placing the designed fiber preform into the mold, closing and compressing the mold to achieve the required fiber volume fraction.

3. Injecting resin into the mold under specific pressure and temperature using specialized injection equipment to displace air and impregnate the fiber preform.

4. Curing the resin at a specified temperature until the curing reaction is complete, then removing the final part.

The resin transfer pressure is a key parameter in RTM that needs to be controlled. This pressure is used to overcome resistance encountered during mold cavity filling and fiber impregnation. The time required for resin transfer is dependent on system pressure and temperature, with shorter times improving production efficiency. However, excessive resin flow can lead to inadequate impregnation and increased system pressure, causing issues. Typically, the resin level entering the mold should rise at a rate not exceeding 25 mm/min. The resin transfer process is monitored by observing the outlet, and it is considered complete when all mold observation ports show resin overflow with no more air bubbles and the actual resin amount matches the expected amount. Thus, careful consideration is needed for the placement of outlet ports.