- How to get fluffy scraps
in a dense form
are machines nobody wants anymore. So
what?, why to edit a page about densifiers?
- What is a densifierand what it does first;
densifiers, also called agglomerators,
are doing nothing but to physically
transform a light, fluffy material in
something heavy enough to feed the hopper
of the extruder or any other machine.
- It is a cylinder where two blades
are spinning at the bottom creating
friction and thus increasing temperature
till material reach the softening point
(not the melting point); operator then
add some water to cool the batch down
and, after water evaporates, from discharge
door material comes out in chips, like
very little pop-corn.
- That's all it does.
- So, what's good about it or anyway
better than any force-feeder ?
- Densifier don't care at all about
the fact material is dry, wet or dripping
water because before going to softening
point it has to dry it first and then
temperature will raise over 100° C and
- Densifier also don't care if you
put into a mixture of material, the
same material with different MFI or
melting point, it will do its job.
- Chips can be therefore mixed into
a silo, so pellets can be a steady quality
as far as lab characteristics.
- Does it start to sound better ?
It is not finished.
- Densifier accepts scraps in any
form, meaning film, ropes, nets, filaments,
non woven and, you name it; result will
be the same for everything, size of
scraps don't matter much as long operator
is safe handling it.
- Maintenance as well is little to
nothing because to replace blades takes
10 minutes for everybody.
- As far as we know, a lot of people
put this machine in a corner and buy
a granulator and a cram-feeder thinking
all the problems were gone. Today
they have the densifier back in
- There are quite many more reasons
to use a densifier, like the fact this
way fluffy material converted in chips
can be accumulated and stored ready
for extrusion so, if something happens
to the washing line, for example, you
are on the safe side and can continue
to make pellets, while fixing the system.
- Having material densified, if something
goes wrong on recycling line and final
product is not very first quality you
can store it and add it at a certain
% in the good material you'll do later
so you don't have to throw it away,
and so on.
- In the next days we'll talk in this
page about the continuous agglomerator.