Filament winding is a technique primarily used to manufacture hollow, circular, or prismatic parts such as pipes and tanks. It is performed by winding continuous fiber tows onto a rotating mandrel using a specialized winding machine. Filament wound parts are commonly used in the aerospace, energy, and consumer product industries.
Figure 1. Filament Wound Parts (Source: Lentus Composites)
Filament Winding Process
Continuous fiber tows are fed through a fiber delivery system to the filament winding machine, where they are wound onto a mandrel in a predetermined, repeating geometric pattern. The tow location is guided by a fiber delivery head, which is attached to a movable carriage on the filament winding machine. The relative angle of the tow to the mandrel axis, called the winding angle, can be tailored to provide strength and stiffness in the desired directions. When sufficient layers of tow have been applied, the resulting laminate is cured on the mandrel. The overall size and shape of the finished part are determined by the mandrel shape and thickness of the laminate.
Video 1. SM+ Filament Winder Commissioning Video (Source: Engineering Technology Corporation)
The winding angles will determine the mechanical properties of the composite part, such as strength, stiffness, and weight. The density of the laminate is the result of the tension of the tows during winding. The composite parts made through these methods generally have good strength-to-weight properties.
Resins: Thermoset resins, e.g. epoxy, polyester, vinyl ester, phenolic.
Fibers: Any. The fibers are used straight from a creel and not woven or stitched into a fabric form.
Cores: Any, although components are usually single skin.
Types of filament winding
Filament winding can be found in two different variations.