Processes

Filament winding is an automated open mold processing technique where resin-impregnated strands of continuous glass fiber roving (Fiberex 408, 410 series or 503, 510 series) is wound mechanically on a rotating mandrel and subsequently cured. The mandrel is normally first covered with a surfacing non-woven veil of glass or polyester followed by an optional one or two layer fiberglass chopped-strand mat to provide a resin-rich interior surface. The individual layers of veil and mat are separately impregnated with resin. Fiberglass roving are then wound on the mandrel at a predetermined angle. The amount and orientation of glass fibers in the molded part (pipe, tank, or pressure vessel) are closely controlled so that a consistently high degree of efficiency in the utilization of filament strength can be obtained. The resin's basic function is to fill the space between the filaments, fix the alignment, and distribute the bonding and shear loads. Due to the much higher modulus of the glass and its normally high percentage content in the composite, the strength effect of the resin is usually minimal.