Cold heading

Cold heading is based on the principle of the deformation of materials in a few hundredths of a second a few hundredths of a second: a slug (of the same mass as the final part piece) is sheared, then upset by several successive blows to give successive strikes to give it its final shape. The origins of cold heading can be found in bolting work with the production of with the production of small parts.

Cold heading is a cold forging process

FIELD OF APPLICATION

The cost of the tools (die, punch) and the very robust machines mean that they are used for very large series production in the automotive, screw and hardware sectors in general. The following parts are generally produced by cold heading:

 

  • the fixing screws (or bolts)

  • the rivets

TYPES OF INSTALLATION

Cold heading machines are extremely robust, as the billet does not have the malleability that heating would give it. High production rate (several thousand pieces per hour). These are horizontal multi-station mechanical presses (up to 7). Need to work under an oil jet to avoid part-die-punch seizure. A very delicate set-up. Very expensive tooling, with several stations to go from the billet to the finished part. The machine is generally fed by a coil of wire (possibly in bars and exceptionally by pre-cut billets).

ADVANTAGES

  • Very high production rate,

  • Obtaining parts without skinning,

  • Improved metal properties through work hardening and fibre drawing,

  • Material savings compared to hot forging or machining or machining,

  • Precise tolerances (of a few hundredths of a millimetre),

  • Good surface condition,

  • Cheaper material