Spread tow fabric

A bundle of thousands of continuous carbon filaments handled as a single unit, the carbon fibre equivalent of a glass roving. Tows are designated by their filament count in thousands, written with a K, and are used directly in filament winding, automated fibre placement and weaving.

A reinforcement fibre produced by carbonising a precursor, most commonly polyacrylonitrile (PAN) or pitch, to give continuous filaments composed largely of carbon. It offers very high stiffness and strength for its weight and is the principal reinforcement in high performance composites. Grades are commonly described by modulus class, such as standard, intermediate and high modulus.

The simplest weave style, in which each warp yarn passes alternately over and under each weft yarn. It is stable and easy to handle but has the highest crimp of the common weave styles, which slightly reduces mechanical performance and limits drape over complex curvature.

Reinforcement fibre pre-impregnated with a controlled quantity of resin, usually a partially cured (B-staged) thermoset, supplied in rolls and stored chilled or frozen until layup. Prepregs give precise fibre and resin content and are the standard material form for high-performance aerospace and motorsport laminates.