Thermal Spray Preforms: An Economical Route to SRIM Composites

An innovative and economical new method has been developed to fabricate glass fiber preforms in the Structural Reaction Injection Molding (SRIM) process to produce structural composite components. The method involves blowing a resin powder through a ring of flame in a commercial thermal spray gun to achieve a melt, and directing the melt onto a fiber reinforcement where the polymer solidifies on contact and binds the fibers together. The fibers are fed through a chopper gun and cocurrently deposited with the binder onto a screen in the shape of the part. A vacuum is applied to the back of the screen by a blower to hold the fibers in place. The thermal spray process has significant economical advantages over the use of mat to fabricate preforms due to lower raw material costs and waste. It also has many advantages over traditional directed fiber processes, including capital and energy savings from the elimination of the preform drying operation. The process is very clean and easily adaptable to robotic operation. Targeted applications include bumper beams, instrument and closeout panels, and seat backs in the automotive market.