cold heading process

Cold Heading Terms:

Cut-off: A specific length of wire that is cut off from a coil of wire prior to going into the heading die.

Heading Die: A stationary piece of tooling that has the specific geometry for the part machined into its cavity used to form parts.

Punch: A piece of tooling that moves, striking the cut-off slug to upset material and push it into the heading die.

Knockout Pin: (used for two purposes)

1. To serve as a support against which the blank rests while it is being headed.

2. To eject the part out of each die.

Diameter of Upset: The amount of material that can be upset to form a head of a fastener. A length of wire equal to its diameter. The term [1 diameter of upset" only moves a small amount of material to form the head of a fastener. The term [4 ½ diameters of upset" involves moving a lot of material to form the head of a fastener. The larger the diameter of upset – the larger the head diameter can be made.

Upsetting: Striking an object on its end causing the existing diameter to increase in size.

Extrusion: Forcing into a die causing the diameter to become smaller

Grain Flow: The grain flow of the existing material is either interrupted (as in machining) or uninterrupted (as in cold heading). A part that has an interrupted grain flow is weaker than a part with uninterrupted grain flow. Cold-formed parts are stronger because the internal grain structure follows the contour of the part.