EuroWire May 2015

24 / 116

News
Corporate
22 May 2015
Ajex and Turner has introduced a new concept of VNT dies
which are a completely new type of diamond dies. The
cable being compacted passes through the hardness of
diamond, but the cost of the VNT dies is less than the cost
of a solid diamond nib. Here, lower cost does not indicate
low quality; what matters is the raw material being utilised
by cost-effective model technology.
Moreover, VNT dies run cooler because they have lower
friction than other dies, so they do less damage to the
microstructure of the conductors during the compacting
process. This results in significantly lower electrical
resistance in the cable conductors. Hence, conductors may
be bright while maintaining fully compliant cable.
These dies are made with multi-layer coatings of
nanocrystalline diamond composites on PCD/hard metal,
which provides an extremely smooth surface with very low
friction. The VNT die can be used for compacting copper,
aluminium or aluminium alloys.
It is well known that the quality of a PCD die deteriorates
over time due to two related factors. The relatively soft
filler materials like cobalt and tungsten wear out, exposing
the jagged edges of the diamond particles and increasing
surface friction.
As this process continues, the work piece begins to ‘pull out’
bits of diamond material from the PCD material and this is
what causes the bore diameter to increase. By comparison,
a VNT die holds a +0 tolerance during its entire life. This
is due to the extreme hardness of the nanocrystalline
diamond surface.
When a VNT die fails, it is not like a tungsten carbide or
PCD die in which a process of steady wear causes the die to
go out of tolerance. A VNT die typically holds its diameter
+0.00 for 600-900km of cable compacted. In some cases,
the die will run for 1,000km of cable compacted.
The VNT die working life is between 15 and 20 times longer
than carbide dies. The surface finish of the drawn conductor
is also superior compared to carbide dies.
Ajex and Turner – India
Website:
VNT dies for cable
manufacturers
▲ ▲ The VNT die from Ajex and Turner