- All shredders, like
any first machine of any line, is supposed to accept
anything. Not true
- If
somebody told you this you have two choices: first one
is to try yourself, and it's going to be expensive,
or be more careful and organize a kind of "inspection"
before loading scraps into it.
- We
are talking about a piece of blade out of hardened steel
left into scraps bale or a piece of the baler that fall
into for no reasons and so on.
- If
something like this goes into the shredder, you can
be absolutely sure the shredder, any kind of shredder,
will be damaged.
- Talking
about single shaft shredders, we found two different
categories; first one is "tearing type" and
second is the cutting one.
- Let's
see the what's good and what not between the two:
- First
one cannot be equipped with any grid therefore the result
in terms of size is unknown or, to say it better, anything
from 100 by 100 (mm.) to 250 by 1000 in the worse case.
- But
the good part of it is the fact this machine needs low
maintenance and it has a low power consumption; also
because power required is directly proportional to the
number of cuttings or, in other words, the less you
cut the less power will be needed.
- Second
type has a grid, so size will be according to grid
holes and rotating blades working against a fixed
one; just like a granulator.
- The
big difference stays in the fact that quantity of material
to be fed to the rotor can be adjusted according to
the kind of material itself; and this is not a little
thing.
- We
do think that all machinery involved in recycling should
be, somehow, adjustable so, whatever material you are
going to have, there will be something to do to make
the machine to perform the best possible way.
- Another category of shredders are
the two shafts shredder.
- Two shafts shredders
are well known to be low power consumption machines.
- On
the other side, maintenance in pretty critical and expensive.
- These
machines, in fact, are well working when slow rotating
blades are well sharpened, meaning if you deal with
clean industrial scraps, you want to go with this but,
if post-consumer scraps is the material you have, you
better pay attention to the cost to sharpen blades and
to the time it takes to open it up and put everything
back together.
- Blades
are working with a shearing effect one against the other
therefore when the edges of blades are gone, the machine
will make a lot of force and production rate will decrease
accordingly.