Composites
Carbon and glass fiber reinforced materials, usually known as composites, combine strength with lightness and are used in industries where this combination is essential.
Mechanical properties of sheet composites need to be evaluated and because of this, test specimens need to be cut from sheet for different testing. Thus the requirement for a cutting machine with a travelling head evolved to cut larger composite sheets into strips. Since test results depend on having parallel test strips with smooth sides, the accuracy and quality of cut pieces using the travelling plate saw is extremely important. The choice of diamond cutting blade is equally important for optimum results.
One example of an important industry which uses composite materials is the Aerospace industry. Composite sheet materials are used in many parts of the airframe. Another typical example of this group of materials is Kevlar, which is also well known for its use in body armour.
Why Composite Materials?
Most composites have strong, stiff fibers in a matrix which is weaker and less stiff. The objective is usually to make a component which is strong and stiff, often with a low density. Commercial material commonly has glass or carbon fibers in matrices based on thermosetting polymers, such as epoxy or polyester resins. Sometimes, thermoplastic polymers may be preferred, since they are mouldable after initial production.
The greatest advantage of composite materials is strength and stiffness combined with lightness. By choosing an appropriate combination of reinforcement and matrix material, manufacturers can produce properties that exactly fit the requirements for a particular structure for a particular purpose.
Composites in Products
Composite materials have gained popularity (despite their generally high cost) in high-performance products that need to be lightweight, yet strong enough to take harsh loading conditions such as aerospace components (tails, wings, fuselage, propeller), boat and scull hulls, bicycle frames and racing car bodies. Other uses include fishing rods and storage tanks. The new Boeing Dreamliner structure including the wings and fuselage is composed of over 50 percent composites. This section would not be complete without a mention of Kevlar. In the 1970s, one of its most significant achievements in the development of body armor was the invention of DuPont's Kevlar ballistic fabric.
Materials Testing Laboratories
The properties of newly developed composite materials need to be tested mechanically and prepared for for microscopic analysis. In addition quality control needs to be done on production materials. In many cases the testing is done in accredited outside laboratories.
Typical tests include Tensile Compression, Flexing, Shear tests etc. In order to obtain reproducible results the preparation of the test pieces is extremely important.
