Composites 101: The Eight Rules of Manufacturing
While many attendees of the inaugural CAMX event are top innovators in the composites industry, some are just starting out. Several of the CAMX pre-conference tutorials held on Monday offered overviews to help newcomers catch up and give seasoned veterans information on the latest industry processes.
Dr. Brent Strong, professor emeritus at Brigham Young University, presented the “Overview of Composites Manufacturing” tutorial, a crash course on just about every fiber, resin, process and tooling material in the composites industry today. In addition, Strong listed eight rules that manufacturers should consider for every composites project, covering both advanced composite materials and FRP.
1) Choose the resin to meet your environmental concerns. What chemical reactions will the materials be required to withstand? Will the materials get wet? FRP projects typically are best for materials in a moderate environment, while advanced composites can withstand extremely hot or cold temperatures. Know how your final product will be used, and choose your resins accordingly.
2) Choose the best fiber to meet the physical requirements. The four primary types of fibers are fiberglass, carbon fiber/graphite, organic fibers and aramids. Select fibers for properties such as tensile, flexural and compressive strength. While there is a wide variety of fiberglass options, manufacturers often turn to electrical glass (or “e-glass”) because of its properties and low cost, said Strong.
3) Control the resin/fiber content. The more fiber used, the stronger the part – until there’s not enough resin to fully coat every single fiber. Because the coating process, or “wet out,” can be difficult, many companies choose to buy pre-impregnated fibers. However, Strong said FRP projects tend to not use prepregs; they are typically used for advanced composite projects.
4) Put the fibers where the loads will be. The manufacturing process must be capable of properly orienting the fibers in the thicknesses needed for load optimization. The fibers can be isotropic, with material properties the same in all directions. The properties of orthotropic materials are different in three mutually perpendicular directions, so their mechanical properties are related to orientation. Most composites, especially advanced composites, are orthotropic. Aerospace applications often use oriented laminar. Each fiber is carefully oriented in different directions to maximize the load-bearing capacity in any given part of the product.