In addition to Sheet wrapping technology – which allows the best quality to be obtained – the most widespread technologies for the production of carbon fibre products are Filament winding and Pull winding. Most of the producers use these for the major standardization of the process and, in general, the lower costs.
Filament winding (the wrapping of the filament)
The process of construction is easier, as the resin’s impregnation is carried out in the same moment as the wire is wrapped onto the mould: the coils in the carbon are turned, letting the filament pass through a container with the resin.
The successive phase, depending on the typologies of the tubes, may or may not consider
, the use of the autoclave. They do not differ much from the ones used in Sheet wrapping.
This is an evolution of the pultrusion process: the carbon fibres pass through a machine that contains:
- a part in which the resin is poured,
- the matrix with the section of the tube to be obtained,
- a polymerization oven,
- two heads of external traction.
The tube then exits continuously from the machine and is composed of interwoven fibres.
The performances of tubular manufacture made with the Sheet wrapping technology are significantly superior to one that is made with the procedure of Filament winding. Indeed, it is much superior to the one made with Pull winding. At an equal stiffness, a tube in Filament winding has a weight, at least, 30% superior to that of a tube in Sheet wrapping, and as a consequence it has an inferior critical speed.