What manufacturing processes are used to construct bicycle helmets?
Liners The liner is the most important part of the helmet, the foam layer where the energy of the crash is managed. Bicycle helmet liners are mostly molded in Expanded Polystyrene (EPS) foam. For the cheaper helmets that make up the largest part of sales in the US market, the techniques are standard ones used in the industry’s “foam shops” for making all sorts of EPS parts. Granules of EPS known as “bead” are placed in a mold and expanded with steam and pressure into the familiar picnic cooler foam. Although this is mostly done in China now, there are several European manufacturers and one large US company making several million helmets per year in Rantoul, Illinois, in facilties sold to them by Bell. Still within the EPS world, the top end helmets require internal reinforcement, usually to open up larger vents, and the techniques for including the reinforcements in the mold and getting them to line up correctly are critical to the manufacturing process. Those techniques are proprietar
