In these days Carbon fibre is the most common fibre at Marström Composite AB, but also glass fibre is used for some applications. The Carbon fibres are a big family of fibres with different performance.
The fibre we mainly use is fabricated from PAN (polyacrylonitril). The production process includes preoxidation, carbonization, graphitization and surface treatment in steps, and the result is an endless carbon fibre with a high carbon content of about 97%.
The carbon filaments are used to produce small tow or large tow, less than 24K (24K=24,000 filaments) called "small tow" and more filaments called "large tow".
As far as mechanical performance is concerned, there are three main groups of fibres;
-The HS (High Strength) fibres are by far the largest group normally made of 12K, 24K, and 48K. This is the most competitive fibre price wise.
- The IM (Intermediate Modulus) offers a good compromise in terms of mechanical properties. IM fibres are normally used in structural parts in aircrafts.
-The HM (High Modulus) is used when rigidity is the determining criterion; we use it often in yacht masts and when stiffness counts.
If you want to learn more about the prepreg process, please read Hexcel's Prepreg Technology... click here