Pultrusion Process Simplifies Manufacture of Composite Structures

April 1, 2008

A simple pultrusion technique is being adapted to lend its simplicity, efficiency, and cost savings to the production of complex composite structures for high-performance military and commercial hardware. With its automated composite shaping technique, KaZaK Composites (Woburn, MA) is manufacturing net-shape structures to the specifications of the user — whether it is a cylindrical utility pole or flat panels for military shelters and containers.

KaZaK developed and advanced its versatile pultrusion technique with Missile Defense Agency (MDA) Phase I and II SBIR (Small Business Innovation Research) grants investigating strong, cost-effective carbon/epoxy missile canisters for the PAC-3 program, specifically to make very straight, large-cross-section (up to 20 feet long) boxes. KaZaK has also built larger "superscale" pultrusion machines, including the world's widest pultrusion equipment, optimized for making composite sandwich panels greater than 10 feet wide and of unlimited length, used for military shelters, ship superstructures, and shipping containers.

How it Works

The pultrusion process is completely hands-off. It starts with dry spools of fiber and/or fabric reinforcement, adds wet resin, then moves the material through a heated tool. The result is a continuously produced stream of low-cost, constant cross-section composite hardware that can be cut automatically to length at the end of the processing line. Pultruded composites, which can be reinforced with many fibers such as Kevlar®, fiberglass, or carbon, can be less expensive and lighter than metal but just as strong, making them suitable for applications ranging from small stanchions on Navy ships, to enormous shipping containers and even the structure of ocean-going vessels.

KaZaK also has an answer for wooden utility poles. The rigidity of the wooden pole that makes it so valuable for its purpose also means that fatal automobile impacts are not uncommon. KaZaK has manufactured a pultruded composite utility pole with energy-absorbing features, as well as a way to reduce replacement time and cost for poles downed by impact, weather, or age. The designed-in collapse mechanism promises to be superior to the current wooden breakaway designs. Because of the composite pole's unique arrangement of fiber reinforcement, it can absorb some of the automobile's energy as it bends in a controlled collapse, thus transferring less energy (better known as trauma) to the driver and passengers. Fewer fatalities and injuries should result when widely implemented by utilities.

In addition, KaZaK's composite utility pole is designed to break cleanly away from the overhead wires that it carries, reducing the damage to the lines and allowing repair work to be achieved more quickly. KaZaK also offers a butt-pole replacement system, which leaves the upper wooden half of the utility pole intact and allows the damaged lower portion to be replaced with the composite base. At four million pole replacements per year, KaZaK's partial replacement base can offer a savings of $5,000 per unit, a number that adds up quickly. The installment of the base can also be performed without disruption to service.

Another application is a self-recovering post, initially developed to replace steel for use around aircraft carrier elevators, but now being marketed as a maintenance-free post for the thousands of roadside signs that are replaced each year. These posts can be bent flat by an impact and can then be restored to vertical after the load is removed.

Where it Stands

The company has worked with the Army to develop a pultrusion-optimized modular shelter system that ships a rapidly deployable 19 × 90' building in a 20 × 8 × 8' standard ISO container. The KaZaK shelter competes with tents for troop housing and buildings for field operations. There is also growing interest in such structures as temporary habitats for non-military purposes.

KaZaK is interested in pursuing non-military applications for its pultrusion technology and is actively seeking licensing, partnership, and teaming opportunities.

More Information

For more information on KaZaK's pultrusion technology, click here  . (Source: MDA TechUpdate, Missile Defense Agency, National Technology Transfer Center Washington Operations)

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