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DORNIER longitudinal stretching machines (MDOs)
DORNIER longitudinal stretching machines (MDOs) are available
for PA, PP, PET and other special materials. A longitudinal stretching
machine always consists of one set of preheating rolls, one set of
stretching rolls and one set of annealing or cooling rolls, regardless
of material to be processed. The rolls can be heated by thermo oil,
hot water or steam and cooling takes place by water or thermo oil.
In case of thermo oil, the oil temperature will be lowered by a heat
exchanger operated by water. On a DORNIER MDO for polypropylene the
preheating rolls will be driven in groups (up to three groups by belts),
where, however, the gears are arranged in a distance of approx. 1
m from the machine with universal joint shafts as drive connection
in order to avoid dust contamination of the film. The stretching rolls
are independently driven and also the cooling or annealing rolls.
For the production of polyester film MDOs are available with up to
three stretching arrangements (multi-gap stretching) to allow stretching
of the film on one or two gaps or even at high temperature. For polypropylene
production the diameter of the preheating and cooling rolls is each
650 mm and on polyester or PA MDOs the diameter of the preheating
and cooling rolls is each 450 mm. The diameter of the stretching rolls
depends on width of rolls. On MDOs for the production of polyester
film the drive of the preheating rolls takes place in groups, however,
on each roll the speed can be adjusted independently of the others
in a range of ± 0.5 % to compensate heat expansion. Besides
of this, however, DORNIER also supplies MDOs, where all preheating
rolls will be equipped with each independent drive. The polyester
film production MDOs are equipped with additional infrared heaters
in the stretching sections. DORNIER MDOs are very robust and sophisticated
machines designed for fast maintenance, i. e. roller exchange is possible
within a very short period.
DORNIER supplies longitudinal stretching machines with or without enclosure (housing).
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| Longitudinal stretching machine for polyester film production |
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