EDITOR’S CHOICE
DIGITAL CONTROL SYSTEM
KHS
FOR MORE EFFICIENT PROCESSES: KHS DEVELOPS
A DIGITAL CONTROL SYSTEM FOR PET BOTTLE
PRODUCTION
Unit Mold Control
yields further benefits
with regard to the
growing percentage of
recyclate used in PET
bottles in particular.
“Process accuracy reaches its limits with
containers such as these,” Haesendonckx
says. “As the material quality varies when
recycled PET is used, the bottle becomes
less and less stable the less the preform
weighs or manufacturers have to use
heavier preforms to ensure stability.”
With the new system weights can be
reduced while retaining bottle stability,
claims Haesendonckx. “Unit Mold Control
effectively compensates for discrepancies
by identifying any unwanted material
displacement during wall thickness
inspection and automatically counteracting
this.”
Even on the most advanced machine there
can be discrepancies in the distribution
of PET bottle material in the stretch blow
molding process. This has an impact
on the bottle quality and production
efficiency. In order to optimize these
parameters KHS recently developed Unit
Mold Control in cooperation with US
company Agr International inc. (Agr). This
digital, automated process control system,
connected with the KHS controller, now
individually regulates the respective blow
stations in KHS’ InnoPET Blomax series,
thus minimizing any fluctuations in quality
during stretch blow molding. This results
in improved bottle stability coupled with
lower preform weights. This had proved
something of a challenge to date, especially
where containers with a high recycled PET
content are used.
On a stretch blow molder the amount of
wear on the individual blow valves used
can vary. This means that the bottles blown
with the same also change throughout
the service life of the stretch blow
molder depending on the station used.
In the production process this can cause
discrepancies in the distribution of material
and thus to differing thicknesses of bottle
wall. To date parameters could only be
46
PECM Issue 41
adjusted for the entire machine and not for
each individual station. With the new digital
Unit Mold Control system manufacturers
optimize their blow molding process by
making individual settings for each station.
“This enables material distribution to be
more precisely controlled per station, thus
minimizing variations in the wall thickness
from mold to mold by more than 30%,”
explains Frank Haesendonckx, head of
Technology at KHS Corpoplast.
Unit Mold Control adjusts settings fully
automatically
To this end, Unit Mold Control inspection
technology constantly measures the
material distribution in each bottle and
adjusts the settings for optimization
fully automatically. “With this system
deviations in the individual mold stations
are identified. By applying an algorithm
the degree of variability is reduced without
operator intervention and possible
incorrect settings are avoided,” states
Haesendonckx. Furthermore, the data
captured from the individual mold stations
provides valuable information for the
condition-based maintenance of valves,
stretching systems or mold shells, for
instance.
Partner Agr is also convinced by the joint
new development. “Our commitment to
the global beverage market is to provide
innovative process control solutions for
the factory floor,” says Robert Cowden,
COO of AGR. “In doing so we’re helping to
constantly optimize processes and improve
production line efficiency and productivity
by reducing unplanned downtime, labor
content per produced container and energy
costs.”
Unit Mold Control is available as an option
for KHS InnoPET Blomax Series IV and
V stretch blow molders and has already
successfully proved itself on the market
several times over. Furthermore, the new
system – whose industrial property rights
are held by KHS and Agr – can also be
retrofitted into existing plant machinery.
For more information go to:
www.khs.com/en/media
Subscribe to our newsletter at:
www.khs.com/en/media/publications/
newsletter.html