Most people assume that all metal parts are formed through the application of heat to metal and then some sort of a forming process. The other option that most people are aware of is the use of machining, which involves cutting away part of the workpiece to create specific shapes.
Another option to consider and one that is often ideal for smaller and more basic types of parts is cold forming. Cold formed parts do not require heat, nor is the material cut away, so it can be a very cost-effective and fast process that provides outstanding results.
How it Works
All cold formed parts are worked at room temperature. As there is no heating involved, there is less time required for production runs and, without the need to heat solid metal to semi-liquid forms to be pressed through the die, there is less energy required in the process.
Instead, with this process, the metal is placed under extreme pressure in a die. The metal wire is lined up in the die and cut to the desired length. Then, pressure is applied with a first blow, which will form the shank or shaft of the fastener. At the same time, there is a punch to form the head on the other end, which forms an approximation of the shape.
Then, one or more different punches can be used to fine-tune the shape of the head. The two different punches to form the head are required because there is a greater deformation of the metal required as compared to simply creating the simple shape of the shaft.
There are more complex machines that may use multiple punches to create the specialized shapes required for some cold formed parts. The entire system is fully automated with self-feeding mechanisms to allow for the continual production of identical fasteners in a very short period of time.