BLOWN FILM

BLOWN
FILM
PROCESSING
FILM ORIENTATION
Orientation is understood to mean the postextrusion
orientation of films in the machine
and/or transverse direction. Biaxial orientation
is the post-extrusion orientation in
both directions whereby monoaxial orientation
refers only to post-extrusion orientation
in the machine direction.
In comparison to non-oriented films of similar
thickness oriented films display superior
mechanical and optical properties. In addition
with barrier films orientation also
improves substantially the Gas and Water
vapour barrier properties. Due to these effects
it is possible to manufacture packaging
films with reduced thickness and as a result
with less raw material to obtain films with
similar properties to non-oriented films. The
potential for cost saving is very high.
Oriented barrier films are ideally suited to
water- and aromaproof food packaging for
e. g. cheese, meat and spices. For the enduser
not only the barrier properties play an
important role but also the tear-opening
characteristics which can be positively
influenced during the orientation process.
ALPINE supplies monoaxial gap orientation
lines (MDO) as downstream equipment in
the film manufacturing process.
Essentially a MDO unit consists of two sets
of nip rollers which are so arranged that a
small adjustable gap is obtained. In this gap
MONOAXIAL ORIENTATION LINES
the film has no contact with the rollers and
can be "stretched". Before entering into
the nip rollers the film is past over heated
rollers and upon leaving the nip rollers is
past over a set of tempering rollers. As all
the rollers are driven and the applied tension
is effective only in the orientation gap,
very thin films can be easily produced.
PROCESS CONTROL
The control and visualisation of the orientation
process is effected by means of ALPINE
software OrVis (Orientation Visualisation
Program) on out-of-line units or parallel
with ALPINE software ExVis on in-line
machines. All important Product Process
and operating data are shown either graphically
or numerically.
CHARACTERISTICS
-Working widths up to 2500 mm
- Exit speeds up to 250 m/min
- In-line operation with a blown film line
or cast film line
- or out-of-line operation from roll to roll
TECHNICAL DATA
- Heating zone
Large circumferential contact for
efficient heat transfer
Tempering with oil
Two tempering units:
number 1 for heater roller 1,
number 2 for heater roller 2 and 3
Lay-on rollers on the first and last
heater rollers
-Orientation zone
Orientation ratio stepless up to 10:1
Tempering with oil
Two tempering units one for each steal
roller
Pneumatically operated rubberised
rollers
-Tempering zone
Tempering with oil
One tempering unit for all tempering
rollers
Independent drive and control for each
tempered roller
- Cooling zone
Large circumferential contact to ensure
efficient film cooling
Cooling medium water
Lay-on roller on the first cooling roller
Cooling unit for all cooling rollers
PROCESS TECHNOLOGIES FOR TOMORROW SM 12 / 13
PROCESS TECHNOLOGIES FOR TOMORROW