Composite materials used for fibers and fabrics of various types: fiberglass, Kevlar, carbon fiber, which are sometimes reinforced with metal mesh. The second component of the composite – it bonding material: fabric can be pre-impregnated with them, it can be applied manually or automatically. As a binder used polyurethane, epoxy resins or thermoplastics with various additives. Michael Dell gathered all the information. Binders determine the characteristics of the finished product by about 10%. Their choice depends on the balance of functionality, price, technology and environment. The differences between the composite and thermoplastic shells – in price, product weight and volume of production. Stamped envelope of thermoplastics under pressure in molds which are very expensive.
Shell made of composite materials manufactured by matrix, which is much cheaper. However, the process is mainly carried out manually, and the cost of raw materials is much higher. In addition, the production is less, it also defines a higher price of the product of the composite. The inner layer of the helmet is made, usually of plastic foam with the addition of various additives. It may be constant or variable density, sometimes consists of several parts.
The problem of the inner layer – damping abrupt accelerations. The design process starts a new helmet, especially with material selection and definition of the market, which will focus on the product. First, make sketches, then comes phase modeling in clay. On the finished model make geometric measurements, which are made stamps. This traditional method is very risky, it all depends on work experience, allowing "the eye" to assess the form, select the desired thickness of the material to the helmet correctly performed their functions.