A continuous filament winding machine (CFW Machine / CW Machine) is a machine for laying filament windings continuously over a cylindrical steel band. The steel band is carried on a forward moving mandrel which is able to collapse and return to the beginning of the travel. The steel band is released after the mandrel collapses and is continuously fed back to the start of the travel where it is again wound on to the mandrel.
This machine is mainly used to manufacture fibre-reinforced plastic (FRP) pipes and couplings, especially glass-reinforced plastic (GRP) pipes. They are used for the manufacture of large diameter pipes and there is a minimum diameter below which the technique becomes unrealistic. Machines are available for diameters from 0.25 to 4.0 m (9.8 to 160 in).
A raw material storage and mixing areas for resins, catalysts, etc. is needed to feed the machine. This will usually involve heating of the chemical mix.
The process of Continuous filament winding is also known as the Drostholm Process. In addition to the continuous advancing band, many alternative methods of filament winding also exist.
The raw material is fed on a continuous steel band. The steel band moves forward a distance equal to its width for each turn. The mandrel does not move forward and there is no collapsable mandrel in the process.
The principle of filament winding is derived from the wrapping of sheets or straps and it can be processed continuously by using computer controlled winding set up. Then the idea of confining concrete by impregnating into the continuous fibre strands was first mentioned by Fardis Khalili in 1981. The first winding machine for column retrofitting was developed by Japan in the mid 1980s.
Examples of continuous filament winding machine producers: