Cold Heading is a process where a length of wire is cut off of a coil and then placed into a die. A hammer will then either UPSET the material (Place a head on it) or EXTRUDE the material (force the wire into a smaller die).
The material will be simply rearranged and therefore there is no loss of material, and typically no scrap .
What are the Advantages of Cold heading?
Upsetting is generally used to create a head on a fastener. There is a limit to the amount of material that can be upset in one blow; therefore forming a more complex part in which more metal is moved farther is better accomplished in multiple stages, or blows, which is why multi-die machines are used.
The head on a standard indented hex washer screw is an example of upsetting on a single die, 2-blow header.
The cut off on top is used to make the hex head below.
Backward extrusion uses an angular punch. Because the metal has no place to go, it literally flows along the outer perimeter of the punch, backwards.
This is useful in forming a variety of cylindrical shapes such as nuts, sleeves and tubular rivets.
The tubes on the right are made from the cutoff on the left. 100% of the material is used.
This is an example of Near Net shape after Cold Heading.
The part on the LEFT is the cut-off from the wire coil.
The part in the CENTER is after a 4-die cold header progression.
The part on the RIGHT has been completed on the CNC.
Very minimal scrap is generated.