How parts are manufactured and produced has a lot to do with the possible shapes, sizes, and options. There are two basic options in metal fasteners when it comes to production. One is to use heat, and the other is to use cold forming.
The Process
Cold forming produces what are known as cold headed parts. These are parts made from an existing length of wire, rod or thin bar that will be further processed without adding heat. In large applications, the wire is typically on a coil and is fed by machine into the equipment that will complete the forming process. The metal is not preheated, so there is no change in the internal structure of the alloy. The extreme pressure, which can be as much as 500 tons, will force the cold material through the die very quickly.
The other option is to use an extrusion process. This pre-heats the metal to a semi-liquid state and then uses force to push the thick semi-solid metal through a die. It creates a shape, but also produces waste material. For many alloys, there is also additional processing required to reverse the changes in the metal during the process and to relieve the internal strain.
The Advantages
All cold headed parts are formed using specific pressure applied to the wire. This process almost completely eliminates waste and allows for the complex shaping of the wire or rod in a very cost-effective manner. The systems are fully automated and controlled by computers, allowing for perfect replication of bolts, studs, specialty and custom fasteners without all the cost of hot forming.
The cold headed parts produced are near net shape. They may not need any additional processing depending on your needs. The parts produced will be ready for screw machining or grinding processes, saving on time, cost and waste in production.