The design and manufacturing considerations for modern
 lightweight military helmets are discussed by an original equipment
 manufacturer (OEM.). The core functional requirements of contemporary military
 helmets are outlined, describing the performance measures that are routinely
 requested to quantify these requirements within specifications. The challenges
 for OEM and end-user are highlighted, as there are many ways of measuring this
 performance and many different levels of performance desired by different end
 users.  
 
 The OEM states the compromises that are made in order
 to maximise helmet performance whilst balancing the complex and competing
 requirements of military helmets. The use of lightweight fibre-reinforced
 composite structures in modern military helmets is described. The composite
 materials commonly used in these helmets are discussed, highlighting the key
 properties of the materials used and the use of hybridised shell constructions
 using many different materials in order to achieve optimum helmet shell
 performance. The challenges faced when hybridising helmet constructions in this
 way, using often incompatible materials is considered.
 
 The two most common helmet manufacturing processes are
 also outlined, and the paper discusses how careful selection of processing
 parameters is key to realise the full potential of the materials used: how the
 increased use of ultra-high molecular weight polyethylene in ballistic helmets
 has led to the use of new manufacturing processes, such as deep draw, for the
 manufacture of fibre reinforced composite helmets rather than the traditional
 compression moulding. 
 
 These preferences and the experience gained during the
 development initiatives are considered to provide insight and guidance to those
 specifying requirements for their own helmets, such as the technical
 representatives of international Ministries of Defence.