Home' FLEXO Magazine : November 2014 Contents ink splash. The ink drop is spherical as it approaches the substrate, but
becomes a long, oval mark, due to the substrate’s relative velocity.
Though these defects might be extremely narrow, they can cause job
rejection. Identifying them as soon as possible, wherever they are on
the web, is essential.
The nature of the substrate also needs to be taken into account and
cameras need to be able to inspect media, whether it is opaque, trans-
parent, translucent or reflective. Since flexible packaging substrates are
usually laminates, they have a high value, so waste reduction here can
have a significant impact on profitability.
ELIMINATING DEFECTIVE COPY
The most effective systems inspect 100 percent of the web 100 percent
of the time and detect both random faults and process faults like:
• Color variation
Systems that enable operators to ad-
just the tolerances independently for
different errors—depending on the
application—give converters much greater control over the process.
For example, spots are highly critical for health care and pharmaceu-
tical applications, where random ones could be mistaken for decimal
points, while color may not be as critical.
Live data collection has been touched on above in terms of press
evaluation and reprints, but it can also play a role in the inspection
process. Data from inspection systems can be used to control the
rewinders, facilitating the removal of defective copy. This not only
ensures that all defective copy is removed, but accelerates the process
by automatically finding exact positions of defective material and
speeding up and slowing down rewinders to locate these at faster
speeds than manual intervention.
Each converter will have its own priorities and a slightly different way
of integrating inspection equipment, depending on the production
line and types of jobs carried out. One factor that may affect decisions
is that press speeds can be anywhere from less than 100 meters per
minute (mpm) up to 800 mpm depending on press type, substrates
and ink used. While most finishing equipment will run in the same
speed range as the press, some converters’ finishing lines will run at
up to 1,000 mpm, making it possible for one finishing line to process
the output of several presses.
This raises the question, “Should I put an inspection system on each
press, or one system on the finishing line?”
At QuadTech, we advocate putting inspection systems on each press,
so defects can be caught virtually instantaneously and the problems
corrected. While more systems are needed, this isn’t a question about
sales; it’s a question about ROI, margins and customer satisfaction.
Individual converters will need to calculate the payback on multiple
systems against the cost of waste that has been fully finished, and it’s
not only that: Overruns and reprints to compensate for anticipated
and real waste eat into a converter’s overall production capacity—and
there is the risk of losing customers.
GREATER THAN THE SUM OF ITS PARTS
Ensuring quality isn’t just about inspecting and removing waste. It’s
also about minimizing the amount of waste printed while maximizing
press production time and volumes of sellable copy printed. Deter-
mining the causes of defective copy is as important as delivering 100
percent defect free print and the recorded job data can be leveraged to
create a competitive edge and improve performance.
These incremental improvements in color management and control,
automation, inspection and verification using the best possible hard-
ware and software accomplish the goals of improving quality, but they
also speed production throughout the workflow. ■
About the Author: With a strong background
in the packaging and converting sector, Stephan
Doppelhammer, QuadTech’s market manager
for packaging, works with converters to help
them adopt strategies for success and profit-
ability and enable them to meet the demands
of international brand customers. His role is
part of QuadTech’s continuing development of
products and services to the global packaging
and converting market.
Current solutions for the market include registration, color control, color
management and Inspection systems. The range of inspection systems
comprises of web viewing, PDF verification and waste management,
as well as its flagship inspection system with SpectralCam solution. For
further information, please contact firstname.lastname@example.org .
56 FLEXO | NOVEMBER 2014
“By automating processes that
require the press to be slowed
or stopped, using reliable print
inspection systems to identify and
correct print faults, and enabling the
efficient removal of defective copy,
converters can make a series of
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