MACHINERY | BLOWN FILM DIES
Right: W&H has overhauled a nine-layer die head for a Varex blown film line at film producer EK-Pack
to a single hose. This saves space on the plant floor, giving easier access around the die for mainte- nance and operation. The company also combines the new single-inlet plenum design with its auto-profile external gauge control (EGC) system, providing an improved starting point (before control) and better end results. “Running the single-inlet plenum with our EGC was a big shock,” said Gautam Jagannathan, software specialist and senior field service engi- neer at Addex.
When using a multi-inlet plenum, the pilot line normally has an expected starting point of profile variability – while there was a noticeable decrease with the new single-inlet plenum “This means the EGC has less work to do since
there is less to correct,” he said. “As an added bonus, we have hints that even bubble stability is improved, which we currently attribute to the removal of multiple mixing points found in conven- tional plenums.” With an improved single-inlet plenum option,
Addex sees strong demand from producers looking to make the switch for retrofits. Overall, processors are attracted to the upgraded single- inlet design because it outperforms the multi-inlet plenum in terms of profile control and the single blower hose allows for easier access to the die.
Production boost DR Joseph says that its Instagauge TDK500 gauge control system can help to improve blown film production in a number of ways. First, it can boost sustainable production.
Accurate gauge control can cut material usage in blown film production through precise control of film thickness uniformity. This helps manufacturers reduce resin consumption. In addition, it can lead to flatter film thanks to the
use of sensors and feedback mechanisms to monitor and adjust film thickness. By minimising
34 FILM & SHEET EXTRUSION | June 2024
thickness variation, producers can achieve higher product quality and meet tighter tolerance require- ments and avoid issues such as uneven sealing or poor printability.
One consequence of this can be higher produc-
tivity. DR Joseph says the InstaGauge achieves target thickness with at least a 50% reduction in gauge variation – in as little as seven minutes. Lower lip lock is simplified with the TDK, which translates into less training and faster start-ups. There is also an improvement in process stability by compensating for external factors that impact film thickness variation, such as die gap variation or ambient temperature. By auto- adjusting param- eters, the system maintains stable production conditions, reducing the risk of defects and giving reliable, repeatable results. The TDK500’s modular construction also allows
for fast, simple lip set swaps to expand the range of blow-up ratios that the unit will support. This allows for greater production flexibility and the ability to meet diverse market demands on one line, with one air ring, says the company.
Die service Film producer EK-Pack Folien is a regular user of the die head cleaning service from Windmoller & Holscher – especially since it bought its first Varex nine-layer blown film line in 2013. W&H was given the task of overhauling the nine-layer die head for the line. The overhaul, which included a new coating, was designed to minimise downtime – mainly because the Varex at EK-Pack runs 24/7.
W&H had a nine-layer die head built for rental
that closely matched EK-Pack‘s configuration and also served as a suitable rental die head for other customers. “In the end, we had almost no production downtime,” said Peter Stober, managing director of operations at EK-Pack.
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IMAGE: W&H
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