In addition to Wrapping technology – which allows the best quality to be obtained – the most widespread technologies for the production of carbon fiber 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 mold: 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 forsee, the use of the autoclave. They do not much differ from the ones used in Wrapping.
This is an evolution of the pultrusion process: the carbon fibers passes 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 fibers.
The performances of a tubular manufacturing constructed with the 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 stifness, 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.