The need for Back Relief

In wire drawing machines the dies
are not fixed, and because of this
they may not be in perfect alignement.

If the exit of the die bearing has a sharp
edge, this can shave the wire.
This will produce metal particles,
dust or "fines", wich can:
- pollute the drawing lubricant,
- block the entrance of the next die.

The friction against the sharp edge
also imparts vibration to the wire,
wich can be transmitted through
the machine.
The negative result of this is:
- abnormal wear of the die,
- numerous wire breaks,
- poor wire quality,
- machine wear...
 

To avoid this sharp edge, it is necessary
to produce a smooth, well blended
transition between the bearing and
the exit of the die.

This gentle blend area known as
"BACK RELIEF", placed at the very end
of the bearing, is becoming more and
more important as the performance
of wire drawing machine is improved
(drawing speed, multiwire, etc...).