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 when the wire is wrapped onto the mould: the coils in the carbon are turned, letting the filament pass through a recipient containing the resin.
The successive phase, depending on the typologies of the tubes, may or may not foresee, the use of the autoclave. They do not much differ 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 Owen,
- two heads of external traction.
The tube then exits continuously from the machine and is composed of interwoven fibres.
The performances of tubular manufacturing constructed with the Sheet wrapping are significantly superior to one that is constructed with the procedure of Filament winding. Indeed, it is much superior to one constructed 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 Wrapping, and as a consequence is an inferior critical speed.