US Patent 9307803 Ballistic helmets and method of manufacture thereof

A method for manufacturing a high performance thermoplastic matrix composite ballistic helmet includes forming/shaping a highly consolidated helmet preform free of wrinkles and with no cuts or seams from a flat stack of 0/90 uni-directional prepreg layers using a pressure forming process. The wrinkle free and no cuts pre-formed helmet shell is pre-heated and placed between match-metal dies in a compression molding press to be molded under constant pressure during heating at high temperature and cooling down below 200° F. in less than 45 minutes. Or molded under constant pressure at high temperature for less than 20 minutes and then the molded helmet is removed from the compression molding press and placed in a hydroforming machine to be cooled down in less than two minutes under a very high pressure while the thermoplastic matrix solidify during cooling down.