ABSTRACT
Liquid composite molding (LCM) processes have several advantages over other composite manufacturing processes. The most important of them are relatively fast production cycle time, low molding pressure, good surface finish, close tolerance, and design flexibility. This chapter describes two different LCM processes, namely, resin transfer molding (RTM) and structural reaction injection molding (SRIM). For manufacturing composite parts with 3D geometry and complex shape, the starting material in an RTM process is usually a dry fiber preform that has already been given the shape of the desired product in a premolding operation. SRIM uses dry fiber preforms that are placed in the mold prior to resin injection. Preforms are preshaped and preassembled layers of dry fiber network with the same shape as the composite part, but not containing the polymer matrix. They are produced separately in a premolding operation and placed in the mold prior to injecting the liquid resin into them.
