Dry fiber preform with improved surface finish

Cannon Tipos, which makes tooling processes for composite materials, and equipment provider Coriolis Composites, have joined forces to make a near to net-shape dry preform.

The companies used high-pressure resin transfer molding (HPRTM) and Coriolis’ patented automated fiber placement (AFP) technology.
The preform features a fiber orientation of unidirectional (UD) non-woven carbon fiber layers (280g/m2 – 8.25oz/yd2 ply) with a 55% fiber volume fraction (FVF) and binding technology reportedly compatible with an injected fast cure epoxy resin system. According to Coriolis, it has improved formability, permeability, and can be trimmed using 3D waterjet to obtain a net-shape contour. It can also achieve an overall reduction of up to 50% in scrap, the company said.

“It is only in the last decade that advanced, cost-effective engineered preform technologies have emerged replacing the need for labor-intensive and accurate alignment of several preforms in a HPRTM mold,” said Andrea Castelnovo, R&D manager at Cannon Tipos. “The innovative near to net-shape dry preform developed through Coriolis’ AFP process and our steel mold, polished to a mirror finish, and high-pressure dosing machines and injection equipment helped realize a complex body-in-white structural part for local reinforcement using a single preform in a fast and easy process with high productivity and sustainable costs.”

Cannon Tipos was able to make a steel mold that can withstand up to 120bar (1740psi), avoiding microporosity. It can also maintain a constant temperature to within two degrees to help ensure optimal resin reaction with the hardener and minimizes counterpressure during the infusion phase and maximize vacuum time to avoid washout and air bubbles, Cannon said. The polished cavities help improve surface aesthetics of the final molded part.