Plastics News - Show Daily - October 22, 2022 - 18

18 * Plastics News, October 22, 2022
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Ossberger reveals injection
blow molder optimized for TPU
By James Snodgrass
Urethanes Technology International
German injection blow molding
machinery maker Ossberger
GmbH + Co. KG (Hall 14, Booth
A04) has exhibited its Pressblower
SB2-260 for the fi rst time at K
2022. The machine is designed for
making fl exible, protective TPU
bellows and gaiters for the automotive
industry.
The demonstrator machine, at
the Weissenburg-based manufacturer's
stand, has been producing
air suspension bellows from Huntsman's
Irogran A 92 TPU, a material
claimed to be oil- and weather-resistant,
fl exible in cold temperatures
and exhibit very good mechanical
properties. The machine has been
optimized for the material peculiarities
of TPU and features twin injection
heads for side-by-side
manufacturing of pieces in
two automated stations.
Ossberger began
business in the 1960s
making machinery for
cosmetics packaging. It
started to penetrate the
automotive industry in
the 1980s and, by the
1990s, when the globalized
cosmetics industry
required mass-produced
packaging, automotive
became the company's
primary focus.
Klaus Haub, sales manager of
Ossberger, explained: " As the cosmetic
industry got more global,
with much more mass production
than before, our process was not
effi cient enough to cover [the volume
needed by] the cosmetics
industry. "
Since the 1990s, the company
has specialized in machinery for
the production of boots and bellows
for the automotive industry.
While the Pressblower machine
is classifi ed as an injection blow
molding machine, Haub believes
this is a misleading nomenclature.
" It's not the classical injection
blow molding. We call it 'pressblow
injection blow molding,' or
you could use the shorter term,
'pressblower.' Injection blow
molding means you are injection
molding a preform which is
blown up. This is not what we're
doing in this case. "
But, Haub said, it is also unlike
extrusion blow molding, where
there is a continuous parison. The
fi rst step in the Pressblower process,
he explained, is the injection
molding of a ring, which is then
used to create individual parisons.
Haub said: " The second step is
that the injection [molded ring] is
moving upwards and, at the same
time, the injection piston is pressing
material out of the accumulator,
through the nozzle, upwards.
So, we have these three synchronous
movements which are necessary
to create a parison, which
has a defi ned wall thickness. "
Ossberger's previous Pressblower
machines were focused
on TPE and aimed at producers
of gaiters of CV joint boots and
shock absorber boots,
with relatively small
diameters compared
with the suspension air
bellows, and steering
bellows, for which the
Pressblower SB2-260 is
designed.
Haub
The market for suspension
air bellows is
increasing, Haub said,
because " there are more
and more heavier cars
- the SUVs, the battery
electric vehicles. "
Haub said: " We had the idea
to enter this market by offering
a machine which is running with
two stations to accommodate
mass production, which allows
bigger diameters than before, and
which is able to process TPU. "
Ossberger had to modify the
technology of its existing Pressblower
DSE 250 and DSE 260 machinery
to meet the demands of
working with TPU and the highly
conformant wall thicknesses
this material necessitates. The
DSE machines were unsuitable
because their plasticizing screws
couldn't process TPU. Haub said:
" For running TPU you need a bigger
diameter and longer length
for the plasticizing screw. And
you need a slower screw speed
- otherwise you shear the material
too much and produce a
material that is too liquid, not
elastomeric enough, to
create a parison. "
After the formation of
the parison, the molds
for the gaiters move into
place, and a blowing unit
expands the parison
from within. The company
says the blowing
unit has 'high clamping
forces' and is suitable
for the production of articles
up to 200 millimeters
in diameter.
The last step of the
process is the simultaneous
cutting of the head
and the base from the
molded parts to reveal a
hollow, cylindrical, concertinaed
bellow.
Currently, Haub said,
only one in three air
suspension gaiters are
made from TPU. But,
with ever-growing
deThe
Pressblower machine is designed for
making fl exible, protective TPU bellows
and gaiters for the automotive industry.
Ossberger GmbH + Co. KG photo
mand for heavier vehicles,
this one-third share
will represent a very signifi
cant market.
http://www.unitechem.eu http://www.fimic.it
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