The process of Liquid Composite Molding (LCM) to produce structural composites has gained considerable attention over the last several years. One barrier to gaining further acceptance is the lack of knowledge and process expertise in preform reinforcement production. If the LCM process is to gain acceptance in the molding industry and retain its advantage of low cost, equally low-cost methods of preform production must be coupled with the molding.
There are two forms of glass fiber reinforcement and preforming methods readily available to process three-dimensional preforms for liquid composite molding. These are thermoforming of a continuous strand mat and fiber directed preforming with a multi-end roving. In addition, thermoforming of a reinforcement product that is a combined chopped strand mat and woven roving is also possible. In this paper, the processes and forms of glass reinforcement will be compared, and examples of fiber directed preforming of the reinforcement for a commercial bumper beam and a headlight housing will be presented.