Centre of excellence for UV printing
Vast improvements in productivity and output have been achieved by the Skanem Group's Willich self-adhesive labels factory in Germany which has just completed a modernisation programme to replace 13 older presses with just five UV-Flexo combination machines.
The Willich plant, on the outskirts of Dusseldorf, began the change-over
in 1999 with the adoption of a mid-term strategy to become Skanem’s
European centre of excellence for UV-Flexo printing.
relative newcomer to the techniques of UV-Flexo printing and Screem
printing, was chosen as the preferred partner and the first MPS press
was installed in 2000. Skanem's managing director at Willich, Thomas
Gottenstroeter, said: "They have been a great partner since our first
meeting in 1999. They understood our technological needs and were quick
to offer us a screen and combination solution with their UV-Flexo
When the first press was installed in 2000, the
Willich workforce began to develop their new UV-Flexo skills and give
added value to both products and customers. Continued investment led to
more new technology which in turn led to more sophisticated products
and satisfied customers, he said.
It also enabled Skanem to streamline the factory's workforce - down from 130 to 85 - and increase output by 50 per cent.
MPS machines lets the printer run either UV-Flexo or rotary screen
operations at any station on the press without having to change print
modules. Hot foiling can also be included.
The MPS technology was
one of the first narrow web machines to make extensive use of servo
motor technology and incorporate double tooling in the same print heads.
change to screen printing from UV-Flexo simply means sliding out the
Flexo inking system and exchanging the squeegee and ink pump. A single
set of press controls operate both print processes.
print unit design is a solid lock feature where the plate cylinder and
impression cylinder are locked together in a cradle. The print pressure
is adjusted by moving the whole assembly, without unlocking the gears,
so avoiding gear marking.
The ink assembly - anilox, doctor blade
and meter rolls – moves automatically as the pressure changes and the
anilox can be changed without losing doctor settings (pressure and
A plate change takes about a minute and there is no web break or re-threading required.
features of the new equipment includes multi-drive technology, with the
web transported independently of the printing/converting process with
separate servo drives for all print and converting functions. Each
printing and converting function has it own register control with preset
capability independent of web transport.
The independent servos
allow web speed and the speed of the plate cylinder surface to be
perfectly matched, regardless of the thickness of the substrate being
run. This avoids barring marks – particularly noticeable on vignettes
which are caused when the web and the plate cylinder are running at
different speeds which happens when the circumference of the plate
cylinder changes as the press operator uses difference tape combinations
to compensate for substrate thickness.
The speed of the dot must
be identical to the web speed for all substrates, both thick and thin
and for this reason the gears are locked together with their own motors.
Among other issues, critical to the printer, that the new systems achieve are:
o Reduction in waste
o Wide width standardisation
o Shorter run lengths capability
o Short set-up times at the lowest set-up waste
o The printed result gives:
o Minimal dot gain, a full round dot, good ink coverage of solid
o Areas and sharper printing of smaller fonts
o Capability of printing one per cent dots up to 200 lpi, matching offset quality in most applications
o Savings in comparison to former UV Flexo generation:
o Make-ready time reduced by 25%
o Waste reduction by 30%
Gottenstroeter said that the complete change at Willich, which is one
of Skanem's ten European factories, has come about as market trends have
changed, which has enabled the factory to meet the new demands.
Customer run lengths has decreased by 20-25 per cent as more variants have been introduced and stock holding reduced.
many jobs now run up to 20,000 linear metres - 4,000 linear metres is
now more normal - which means average running time on the presses is
reduced to two hours instead of 10-15 hours.
Each shift now
averages four changes and there are three shifts a day. This is helped
by reduced setting-up times - now ranging from 30 minutes to two and a
half hours depending on complexity. A streamlined approach means that
while one job is running, the next is on the bench ready and the third
is in preparation.