“Spread tow” refers to the practice of spreading a fibre into a thinner, flatter reinforcement, for example a 5-mm wide 12K high-strength (HS) carbon fibre tow is commonly spread to a 25-mm width tape. This unidirectional tape can then be used in automated tape laying (ATL) and automated fiber placement (AFP) processes. It can also be used to produce thin woven fabrics or multilayered noncrimp fabrics that can be used for infusion or even hand lay-up applications.
Spread Tow reinforcements are extremely thin (can weigh as little as 15 g/m2 with a thickness of only 0.02 mm), ultra-lightweight, have near zero crimp and fewer interlacing points. Due to its lightweight nature, visual appearance and improved performance, compared to traditional textiles, our Spread Tow fabrics are ideally suited to high-performance applications such as sports and leisure equipment, automotive and aerospace.
- Attractive aesthetic finish: ideal for the production of both parts and tooling. No print-through issues on gelcoats.
- Improved mechanical performance as a reduced thickness compared to standard 2D fabrics using 1K fibres.
- High resistance to crack propagation for improved damage tolerance.
- Spread tow also has proven useful in the design of laminates that withstand significantly greater stress before first-ply failure and last-ply failure.
- Much less crimp, so they can absorb more energy when suffering an impact. More crimp lowers the load-carrying maximum of the fabrics.
- Increased fibre volume fraction compared to 2D weaving. Weight savings.
- Improved coverage – reducing effects of multi-ply stacking.
- No added stabilisation during the production process.
The flatness of spread tow means filaments are straighter than those bundled in normal fibres. This results in more efficient load-carrying capability, by weight, and improved surface finish, as well as an aesthetic appeal. Spread tow is the starting point for an iconic “woven look” seen increasingly in sporting goods, small airplanes and motorsports applications.
A greater number of thinner plies makes a stronger and tougher part than fewer, thicker plies. Because the layers are so thin, this achieves a kind of homogeneity, with very good resin-to-fiber distribution, which improves filament-to-filament load transfer for higher performance.
Large aircraft OEMs are combining thin plies with traditional thick plies. “For example, five thin plies with 10 standard thick plies gives an interesting crack propagation behavior that allows them to tailor the damage tolerance performance in the aircraft structures.”