- Plastic scraps must be converted to flakes for processing.
- Because here we are
talking about granulators that will handle dirty stuff, characteristics we
should look after are steel used to build wearing parts, and how long it takes
to replace blades.
- In fact, downtime caused
by replacing blades of granulator does effect the cost of
final product.
- There are two main categories
this machine can be divided into: Dry and Wet.
- Everybody
can understand the difference between the two but now
let's see the good and bad points of each one of them:
- Granulators
running dry are used for all industrial scraps that
doesn't need washing.
- Dry
operation makes machine more productive because it can
be equipped with a powerful aspirator (blower) sucking
chips out of the grid and, in the meantime, cooling
the chamber, the rotor and the material itself.
- Maintenance
is pretty easy due to the fact nothing will get rusted,
including the screws holding the rotating blades.
- Shaft
bearings will last forever if some lubrication is provided,
because water will never get to them.
- Granulator
running wet (it means with water) will be less productive,
comparing two granulator of the same size, but blades
life will last a little longer in case of dirty material
and, most important thing for us, making friction it
definitely has a washing effect, that's exactly what
we want. Isn't it ?
- So,
while in the dry operation friction does create useless,
and sometimes unwanted heat, in a wet environment it is
very helpful doing what we want it to do.
- Cutting and
washing together.
- At this point it's easy
to understand materials used for
the construction of the body and the rotor, is an important matter
indeed.
- Blades are another story
because, does not matter what you do, they wear out according to quantity and
quality of dirt it arrives to the machine and very little can be done about
it.
- A pre-washing machine can
help to overcome the problem but, still, your feeling will be that time between
blades replacement is always too short.
- Shape of the blades,
steel used, the hardening, the speed of the rotor and another hundred parameters
effect blades life so, to buy a granulator is not an easy job because it should
be very specific for the situation you are going to be in.
- One
more important matter is the time it takes to replace
blades and how long it takes the fine tuning meaning
adjusting the gap between rotating and fix blades.
- If
you do have a granulator already, you know what we are
talking about while if you're just starting, pay a lot
of attention to it because, once again, downtime cost
a lot of money and every hour you save, as far as
maintenance, decrease you final costs quite a
bit.
- There are two other
factors about the working environment:
- Vibrations and
noise.
- Both of them can be
avoided; it is just matter of money so, you better choose to take care of this
right at the beginning because later modifications will cost much
more.
-
