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When a pallet of goods is completed, it
is moved to the stretch hood installation. This can be done either by roller
conveyors or the pallet can be put directly on to the stretch hooder with a fork
lift. Note that the pallet is put on a kind of piedestal. Thanks
to this piedestal the machine will be able to cover the pallet with stretch
hood foil until under
the pallet which makes the pallet completely hermetic from the outside world !
Once positionned on the
machine an electronic eye is measuring the height of the pallet. Some
more sofisticated stretch hood lines are also looking at the dimensions of
the pallet. In function of this information the machine will choose
which stretch hood foil to use (in that case two foil formats are mounted on the line).
Note that with one size of stretch hood foil you can pack several formats
of pallets, but when they differ to much you need to use different foil sizes (e.g.
for 60*80 CM and 110*130 MM pallets you should better use two formats of
tubular stretch hood foil).
With all these
dimensional informations the machine will roll of the needed length of the
correct stretch hood foil. Once the length reached, the foil is sealed
together and cut of the roll.
The foil has been rolled of on four
mechanical arms. This process is very important because it influences
a lot the end result of the packed pallet. When badly positioned
on the arms, the stretch hood will show up wrinkles or it will not be put equally
over the four sides of the pallet.
Now it is time to stretch the hood.
With Plastic Union's mevastretch foil you can stretch out the foil up to
more than 100%. This gives you a lot of flexibity when a same stretch hood is used
for several pallet formats ! Once the foil is stretched the circumference of
the foil is bigger than the one of the pallet and now the next step is ready
to take place.
The mechanical arms are going down until
under the pallet, by doing this the stretch hood is placed nicely over the pallet
and from the moment that the stretch hood foil leaves the mechanical arms the foil comes
back to its original format helding the pallet together ! The smaller
the original stretch hood size was, the higher the tension will be on to the pallet.
For some applications a maximal tension is desired (eg stone bricks)
but for other applications this has to be avoided (eg too much tension on a
tetra pak milk pallet could deform the boxes).
The job is done, the arms are going up
again and the pallet can be taken of the stretch hood line, ready to be
piled up in the warehouse and to be shipped safely all over the world !
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