Composite materials have influenced manufacturing since the earliest human structures were built several thousand years ago. Ancient materials such as bricks, plywood, and concrete formed the foundations of the building sector as we know it.
These materials remain in frequent use today but, in recent years, a number of technological advances have helped composite manufacturers produce even stronger building materials that suit a wide range of industries. Indeed, modern composites lie at the heart of large-scale engineering and manufacturing, forming the backbone of products ranging from the heat shields of spacecraft to the disk brakes of sports cars.
This marriage of science and manufacturing should only continue to transform American industry in the years to come.
Composite Manufacturing: Three Major Processes
In essence, a composite material solves a problem that a single material can’t handle by itself. By combining two or more materials, the finished composite can be infused with the properties of each. As a result, these materials are often stronger, lighter, and more durable than any of their components alone.
Composites can be used to fabricate many devices and structures. Reinforced concrete and metal matrix composites, for example, take advantage of a matrix, or binder, paired with a desired reinforcement.
Similarly, fiber-reinforced composite materials are widely used in aerospace components, racing care bodies, and sporting goods. These materials can be crafted in the form of a resin or epoxy. The solution used during production is often a polymer material that can be combined with ground minerals or fiber reinforcement.
Composites are usually molded with three primary methods:
- Cast polymer molding utilizes composite resins and fillers which are poured into a mold. This process does not rely on reinforcements, and the composite cures or hardens to take on its new shape.
- Open molding combines resin and fibers in an open mold, which exposes the materials to air. The form then cures and hardens to create the final product. This style of molding has a lower tooling cost than closed molding, making it ideal for prototyping and short runs.
- Closed molding cures composite materials inside of a vacuum-sealed bag or a two-sided mold. As a result, these products have no exposure to the atmosphere during processing. This method works well for high production volumes, and can also be utilized to create a two-sided finish.
The Science of Composite Manufacturing
Due to the wide variety of materials that make up industrial composites, and the vast array of parts they’re used to produce, there isn’t a single method of manufacturing composites. The specific process largely depends on the demands of the industry or the finished product’s intended application. Some of the most common production techniques include:
- Manual layup, which utilizes hand and power tools to manually cut reinforcement material. The custom cut pieces are then combined with a wet matrix selection and rolled over a treated mold surface for uniform distribution before curing.
- Automated layup applies CNC machining to the standard layup process, especially in production for the aerospace industry.
- Sprayup treats a prepared mold surface with a specially designed spray gun. The gun distributes a composite resin over the mold while chopping a continuous reinforcement material into suitable lengths for the finished product.
- Filament winding is used to produce hollow shapes such as pipes, tubing, tanks, and pressure vessels. The composite material for this process begins as a narrow fiber tow or a band of tows of fiber prepreg, which means that the material has already been impregnated with composite resin.
- Pultrusion creates long, straight composite shapes with a constant cross-section. The material is pulled through a die for shaping and utilizes continuous reinforcing fibers.
- Resin transfer molding is the process behind composite bath and shower enclosures, pools and hot tubs, and other similarly large and complex items. Aircraft parts, automotive components, and composite cabinets are all created through gravity and pump-fed transfer molds.
Growing Into the Future
The science behind composite materials is only improving, and their popularity continues to rise. Composites support nearly every industry, including transportation, construction, oil and gas, infrastructure, marine, electrical, appliances, consumer products, aerospace, automotive, and sports. Indeed, their practical applications become more numerous every day.
Composites are highly versatile materials, designed to meet or exceed exacting performance demands. Sophisticated cosmetic finishes, light weight, spectacularly high strength, critical corrosion resistance, and unmatched durability are just a few of the many advantages offered by modern composites. With continued research and development, the possibilities afforded by modern composites are nearly endless.
Image Credit: TLaoPhotography/Shutterstock.com