WCA January 2007

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Technology News
36 Wire & Cable ASIA – January/February 2007
New version of kneader
for calender feeding
Buss AG, Switzerland, has launched
a new version of its quantec® high
performance kneader for use in the
compounding of high grade PVC
pellets for extrusion and injection
moulding. The new machine has been
optimised for direct feeding to PVC film
calenders.
Throughput is adjustable in a range of
1 to 3, with improved process stability,
and the machine is more compact,
saving space and investment cost. A
newly developed intermittent cutting
device ensures non-adhering PVC
pieces of uniform size, and the shut-
down time required for opening,
cleaning and closing is reduced to
between 30 and 50 minutes.
Melt quality meets high demands for
homogeneity without pinholing, for
colour uniformity, and for degassing, all
of which are essential requirements for
high quality PVC film calendering.
The quantec version for calender
feeding is a single-stage machine, ie
it has no additional discharge screw.
Instead, the length L of the mixing and
kneading part, normally in the ratio
10 to 11 L/D (where D = screw dia-
meter), is extended by 4 to 5 L/D. The
additional space serves for degassing
the melt and building up the necessary
discharge pressure with minimal energy
input. This single stage
design offers quality
and cost advantages:
processing is simpler,
and the residence time
under thermal and
mechanical loading is
shorter than with two
stage processing. As
a result, the sensitive
PVC melt is less liable
to burn, so process
stabiliser consumption
can be reduced.
At the end of the
processing section
the finished PVC melt
is extruded through
one or more large cross-section
nozzles. It is then divided by a cutter
with an innovative control system:
the intermittent cutter knife timing is
synchronised with the screw motion.
As a result, the knives always cut at
the beginning or end of each cycle
when practically no material is being
transported. This ensures a smooth
cut, and PVC pieces of uniform size.
After cutting, the pieces fall onto a
conveyor belt which transports them
to the calender roll nip, with enough
space between them to prevent
sticking together. Individual pieces
make for better and more uniform filling
of the calender roll nip, which improves
PVC film quality.
Buss AG – Switzerland
Fax: +41 61 825 68 58
Email :
Website:
A quick and easy twist
It’s 95 th anniversary celebration time for Eraser, manufacturers of a wide range of industrial
products. Eraser’s Model G10S bench wire twister is used for many diverse twisting
needs, twisting pre-stripped stranded wires, twisting strands of two or more wires
together, twisting wrapped shields on coaxial cables and tightening the twist of already
twisted wire.
The G10S is supplied with one set of three twist length spacers to vary the twist length,
depending on application needs. Twisting inserts can be ordered depending on wire size
to be twisted.
Eraser – USA
Fax: +1 315 454 3090 • Email: • Website:
The quantec kneader for calender feeding features high melt
quality, user-friendly handling and easy cleaning
▲
The new quantec kneader from Buss incorporates a newly developed cutting device to ensure
PVC pieces of uniform size
▲
Eraser’s G10S Bench Wire
Twister
▲