Cold Forming Principles

What is Cold Forming?

Cold forming is a high speed forging process where coiled wire at room temperature is precisely sheared to length, and then moved through a succession of tool and die cavities to displace the working metal, either larger/smaller in diameter, longer/shorter in length, or to remove small amounts of material by trimming or piercing.

Metal is forced beyond its yield (elastic) limit and retains its altered shape upon removal from the die. The metal is not forced beyond its tensile strength, otherwise fracturing would occur (the exception is when trimming or piercing). Historically cold forming has been an experienced based technology, but this is changing as new computer based analytical tools are constantly being developed.

Cold forming the chosen material into a given part shape is governed by that material's structural properties. These properties help makeup the "rules" of how to form parts, all based off the combination of 3 basic forming methods.

FORWARD EXTRUSION - Method to reduce diameter where depending on % of reduc-tion is open or trapped for material to flow into the cavity of lesser diameter. (click on image for animation .mpg)

BACKWARD EXTRUSION - Method to make holes, where material flows backward around a penetrating punch.
(click on image for animation .mpg)

UPSET - Method to form heads on fasteners, where material is upset at the face of dies and can be open or trapped to upset a particular shape. (click on image for animation .mpg)