RTM production process

Resin Transfer Moulding (RTM) is a process method in which resin is injected into a closed mold to infiltrate the reinforcing material and cure, similar to the pouring process. This technology can eliminate the need for prepregs and autoclaves, effectively reducing equipment costs and molding costs. This technology has developed rapidly in recent years, and has been widely used in the aircraft industry, automobile industry, ship industry and other fields, and has developed a variety of branches such as RFI, VARTM, SCRIMP, SPRINT, etc., to meet the application needs of different fields.

The main raw materials of RTM process are composed of reinforcing fabrics (fiber cloth, felt), unsaturated resins and various additives. It is also similar to the hand-hu process, which roughly involves laying a reinforced fabric in a mold and then injecting resin, and then heating and curing. Among them, the molding process mainly includes the following materials:
1. Release agent
Inner release agent, outer release agent, mixed release agent;
2. Resin
UP, EP, VE, etc ;
3. Reinforcement materials
fiber cloth, felt, sandwich material, prepreg, etc ;
4. Auxiliary materials
Polyurethane foams, fillers, colorants, etc.
With the increase in product demand, a variety of molding processes have been added, such as glue brushing, vacuum pumping and other processes. The biggest feature of the RTM process is that it has little pollution, and the resin is injected and reheated after mold closure, which is better than SMC AND BMC/DMC in terms of product designability, directionality enhancement, and comprehensive performance of products.

At present, the common RTM processes include RTM resin injection process and RTM resin vacuum suction process, and the process sequence is roughly similar, with only one difference, as follows:
1. RTM resin injection process
Mold cleaning→ application of release agent→ laying of reinforcement materials→ sealing and clamping→ high-pressure injection resin → heating and curing, cooling → opening the mold, and taking out the product
2. RTM resin vacuum suction process
Mold cleaning→ application of release agent→ laying of reinforcing materials→ sealing and clamping→ vacuum sucking resin→ heating and curing, cooling → opening the mold, and taking out the product.

The above is the relevant introduction to the RTM molding process, from the above, it can be seen that the derivative processes of RTM are endless, but they are mainly to reduce waste and reduce costs, and at the same time are conducive to green environmental protection and sustainable development.