Resin Transfer Molding (RTM) is a liquid composite molding process.
Unlike materials used in RIM or SRIM processes, where the chemical reaction is activated by mixing the reactants, the chemical reaction for resins used in RTM are thermally activated by heat from the mold wall and fiber mat (preform). The reaction rate in RTM processes is typically much slower than that in SRIM, allowing a longer fill time at lower injection pressure.
RTM is a process for the manufacture of fiber-reinforced composites. The resulting light-weight, high strength parts are attractive for many applications. Examples are chairs, automobile parts and aircraft components. RTM is of interest to the aerospace industry because it promises cost savings and performance improvements over traditional methods.
In the RTM process, dry fiber reinforcement, or fiber preform, is packed into a mold cavity which has the shape of the desired part. The mold is then closed and resin is injected under pressure into the mold where it impregnates the preform. After the fill cycle, the cure cycle begins, during which the mold is heated and resin polymerizes to become rigid plastic.
The greatest benefit of RTM relative to other polymer composite manufacturing techniques is the separation of the injection and cure stages from the fiber preform stage. Liquid molding also enables high levels of microstructural control and part complexity compared with processes like injection molding and compression molding.
The following table shows the available analysis technologies for an RTM/SRIM analysis type.