Filament winding is a process in which a pre-programmed robot arm applies a bundle of resin-impregnated fibers onto a spinning mandrel. After the desired layup has been finished, the mandrel is placed in an oven to cure. After the curing process, the mandrel is removed, leaving a filament wound, hollow tube.
Advantages of filament winding:
The ability to make very thin-walled products in relation to their diameter
Because various winding angles are used, an optimal balance between tensile strength, hoop strength and torsional resistance can be created. This, in combination with a high fiber tension when applying the filaments, results in a relatively thin walled product.
Consistent product quality due to the highly automated nature of the process
The tension of the filaments, and the resin/fiber proportion, amongst other variables, are computer controlled, to a much higher degree of consistency than a human operator could. This leads to less variation in wall thickness and straightness in the finished products.
High amount of freedom in determining structural properties
The orientation of the filaments is carefully controlled so that successive layers are oriented differently from the previous layer. The angle at which the fiber is laid down will determine the properties of the final product. A high angle “hoop” will provide crush strength, while a lower angle pattern (known as closed or helical) will provide greater tensile strength.