Why this comparison?
On every Post Press project we have
two challenging choices ahead of us:
1) What are the right machines for the
productions which will be run on the press
2) How do I layout these machines in
order to optimize
ƒ
the
available space and the plant logistic
ƒ
the
product flow through the system (including intelligent back-up
ƒ
the
ergonomics for the operators (easy access, free floor space, safe environment)
This
comparison wants to be a help for question 1) with a focus on small and medium
presses with limited need of automation where the Post Press mostly consists of
a conveying system and either a compensating stacker (optionally with a
trimming line) or a semi-automatic log stacker.
Unfortunately we still see plants
inefficiently running books, directories or magazine work through a
compensating stacker or retail work through a log stacker from where they pile
down loose bundles.
Here the two
main question which help to make the right choice:
ƒWhat
will the press print : books – directories – magazines & catalog –
inserts – newspapers
What
is the degree of automation (manual pocket feeding or stream feeders) in the
bindery
Here under a fast and simple guide to
what could be the best machine for your operation. It is not a “black or white”
choice since space; budget, future plans etc. will also influence the choice:
Compensating Stacker - best for..off the press products“
- For retail applications, with our without trimming (finished products)
- For Loose, compensated bundles, 100-250 mm
- Newspaper printing (direct print, at the end of inserters,..)
- Builds loose, counted & compensated bundles behind web presses
- As alternative solution in magazine / catalogue printing to handle WIP
Speed
|
pagination
|
sizes
|
application
|
<120 .000cph="" span="">
|
2-128p
|
magazine-tabloid
|
heat set + coldest
|
Semi-automatic Log Stackers – best for „work-in-process“
- For magazine / catalogue applications (unfinished work-in-process WIP)
- For book & directory Compressed, counted and secured logs, 450 – 800mm
- Printing (direct print, at the end of inserters,..)
- Builds compressed & strapped logs behind web presses
- Copies in the strapped & stable logs are secured between two end boards
Speed
|
pagination
|
sizes
|
application
|
<70 .000="" cph="" span="">
|
4-64p
|
magazine-tabloid
|
Heatset + coldest
|
COMPENSATING STACKER
|
LOG STACKER
|
Delivers loose, counted, compensated and unstrapped bundles
|
Delivers counted, compressed, uncompensated logs secured by two
end boards and safely strapped.
|
100-250 mm bundles height ( in average)
|
450-800 mm log length on semi automatic
log stacker.
|
No need of consumables for the loose
bundles. Possibly need of consumables ( strapping belt/film) to stabilize &
protect the pallets
|
End boards and strapping material needed
for each log. Normally no additional cosnumables needed to stabilize &
protect the pallets.
|
The stacks are only shortly compressed in
the stacker. After placing the products on the pallet the spine will tend to
build up again ( memory effect on the paper). The higher position of a bundle
on the pallet the more air will be in the bundle>no uniform bundles
|
The logs are compressed resulting in
completely flat sections with no risk of folded edges. No alternation will
happen to the products once they are placed onto the pallet> all products
are flat & uniform.
|
The loose bundles on the pallet are
unprotected. They tend to move, especially in the lower layers. Loose bundles
are exposed t dust, temperature and humidity. The level of compression also
varies with the position of the bundles on the pallet ( with high compression
on 1st layer, no compression on last layer).
|
All products in the log are equally
compressed. The products in the log are protected, they can not move (
neither in the log nor on the pallet). The products are not exposed to dust,
temperature or humidity.
|
Slip sheets & pallet film wrapping
will protect the loose bundles. This adds costs for labor & consumables.
The use of film can lead to folded edges of the sections which can increase
the risk of jams in the bindery. Optionally carton corners can be used before
film wrapping.
|
Slip sheets may be used but no film is
necessary. No costs for additional consumables. No folded edges of the
sections.
|
Work load of a compensating stacker is
higher-higher frequency of bundles which are mostly placed manually on a
pallet. Example 7 layers x 14 stacks = 98 movements per pallet.
|
Lower frequency of logs which can be
placed manually ( short logs) or by means of a semi-automatic clamp or a log
palletizer on a pallet. Example: 4 layers x 4(6/11) logs = 16 ( 24/44)
movements per pallet.
|
One man operation on compensating stacker
behind slower and smaller presses. Two men operation on compensating stacker
behind high volume and faster presses.
|
One man operation on semi-automatic log
stacker. One man operation on two fully automatic log stackers (
configuration allowing).
|
It is difficult to stack pallets with
loose bundles w/o damaging the product. Securing the pallets entails
additional costs.
|
Easy stacking of pallets.
|
Pallets will have to be shrink wrapped if
transported to a bindery which is not in house.
|
Printed products are secure whether to be
taken to a bindery in house or outside. Only end boards need to be returned.
|
