To create fasteners through hot forging, the metal is heated before the forging process during the forming process. Cold forming is quite the opposite. This process, which became commonplace after World War II, is where the metal is shaped at room temperature, as opposed to being heated.
How Cold Forming Works
Essentially, the process of cold forming is placing the material in a die and forming it with multiple blows within the machine. The first punch provides the initial shape of the piece before the second punch finishes the shape of the head. A knockout pin will then push the piece out of the die, once the two blows have been delivered. More complex shapes can be formed with a multiple-die header (up to 5 dies). A mechanical transfer process transfers the part from die-to-die.
In addition to offering a more efficient use of the material, cold forming is known to produce very strong parts, in large part due to the compressed grain structure of the material after it has been formed into the desired shape.
Another considerable advantage of the cold forming process, it can produce parts very fast, sometimes up to 200 parts per minute.
Tooling for cold forming can be an expensive investment. The overall cost of the tool set depends on the complexity of a part is being produced. Cold forming is not always considered a cost-effective method for small quantities of a part. The design and set-up required for cold forming can be many hours, which stands in stark comparison to the significantly less time required to set up a machining center.
Cold forming can be very effective to manufacture parts with unique shapes, but it is important to first know whether cold forming is the most cost effective method for achieving your desired level of production. To learn more about the cold forming of fasteners and the limitations of using cold forming versus machining, contact Bossard at ProvenProductivity@bossard.com.
Cold Forming Fasteners and Limitations by Bossard