NMHeader Cold Forming Principles

Cold Forming Principles

 
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What is Cold Forming?

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.

Basic Steps of Cold Forming

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. To learn more about the process of cold forming attend one of our Tooling seminars.
FORWARD EXTRUSION - Method to reduce diameter where depending on % of reduction is open or trapped for material to flow into the cavity of lesser diameter.

Forward Extrusion animation from National Machinery LLC.

BACKWARD EXTRUSION - Method to make holes, where material flows backward around a penetrating punch.

Backward Extrusion animation from National Machinery LLC.

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.

Upsetting animation from National Machinery LLC.

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Cold Forming Trouble Shooting Guide
Cold Forming Glossary of Terms

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