Pultrusion in the creation of glastic angles structural composites
Pultrusion is a cost effective process of producing continuous length profiles of fiber reinforced polymer composites that come in various shapes from rods, bars, tubes, angles and channels. The right choice for the fiber reinforcement and resin will allow a unique blend of the desired properties on the composite. For example, the right blend can result into corrosion resistance, dielectric properties, ease of fabrication, heat resistance and dimensional stability. Flexibility in design and the possibility for different material combinations is main advantage of pultrusion technology. The possibilities for a wide range of structural composites are possible.
There are several choices for fiber reinforcement from aramid, carbon and fiberglass. Epoxies, phenolic and thermoplastics are resins that are pultrudable as well as polymers from the family of polyesters and vinyl ester. The most common material used for composites is fiberglass because it is more cost effective. The raw resin is usually a thermosetting resin but it can be combined with fillers, catalysts and pigments to provide the part with color. Many manufacturers of glastic structural composites make use of CAD technology to optimize the shape of the part and the materials included in the composite. Fixtures will be designed including a resin impregnation system to ensure that the part will be consistently produced with the specific performance characteristics.
The fiber reinforcement will be impregnated with thermosetting resin until all the fiber filaments are fully saturated with the resin mixture. As the resin-rich fibers exit the resin impregnation system, the uncured composite material will be guided through a series of tooling or pre-former. Custom tooling will arrange and organize the fibers into the desired shape while any excess resins will be squeezed out in a process that is called de-bulking. In certain instances, a continuous strand mat and surface veil are added for the purpose of increasing structure and surface finish.
After the removal of excess resin the way the impregnated fiber is organized has to be checked before the composite passes through a heated steel die. The die is heated to a constant temperature with several zones of temperature throughout its length in order to cure the thermosetting resin. The profile that exits the die is the fully cured fiber reinforced polymer composite. At the end of the process is the cut off saw that will be used to cut the pultruded profiles to specific lengths before they are packed for shipment.
One of the outstanding advantages of fiberglass-reinforced polymer composites is their ability to perform for a long period of time in different environmental conditions. This is the reason why industries today are looking at pultruded composites as an option to steel in some applications.