Nov 22, 2018
When the Poledno corrugated box plant in Poland started to use Valmet’s IQ Moisturizer system to reduce warping, they soon noticed additional improvements besides reduced waste thanks to higher machine speed and increased production flexibility.
Warping is one of the most serious defects that can occur on corrugated boards. Differences in moisture content in the top and bottom facings cause the sheet to warp or bend towards the side with higher moisture. For sheet-fed converting or printing, having flat sheets is extremely important for trouble-free feeding of the machines.
Schumacher Poledno had had a relatively good re-moisturizing experience with an earlier device installed for testing purposes in 2015 to improve the quality of corrugated board and reduce production losses caused by warped board. However, for Wojciech Lupa, Corrugator Manager (picture on top), a test run in late 2016 with a Valmet IQ Moisturizer unit showed that additional improvements could be made to control warping. “Our main idea was to further reduce the waste caused by warping.”
In August 2017, a two-beam Valmet IQ Moisturizer system was successfully started up to control warping on Poledno’s 2.8-meter-wide line producing corrugated board. “Since the installation of the two IQ Moisturizers before the double backer, we have reduced waste by 30 percent, and we have also been able to substantially increase the machine speed,” says Lupa.
Warping problems can cause jams in various kinds of converting and printing equipment, interfere with the stacking of paper and board products, and make the appearance of the product unacceptable. The IQ Moisturizer corrects warping in combined board by spraying a fine mist on the top and bottom of the sheet in a controlled way, providing a very high degree of control and very fast response to conditions that negatively affect quality.
Poledno manufactures five-layer boards with B, C and E flute combinations at various weights. “We found that during our trial with Valmet, the IQ Moisturizer with its atomized spray was especially better with heavy grades, achieving much better penetration of water than our earlier system. Now with heavier grades, the two rows of atomizing spray nozzles deliver as much as four grams a square meter without streaking and, as well as eliminating warp, have enabled a 20-percent increase in machine speed.
IQ Moisturizer’s profiling capability is particularly useful to cure S-warping, and operators can easily make adjustments from the control room when they see the first sheets from the machine,” says Lupa. The control system delivered with the moisturizer takes care of production rate changes automatically, so during reel changes or grade changes when the machine speed is changing, the moisturizer adapts immediately.
“With a smooth installation and startup, our experience with Valmet has been very positive. Training for both operators and maintenance staff was good,” declares Lupa.
As well as producing high-quality packaging products, Poledno also supplies board for other producers with stringent quality demands. “We have a very good customer requiring heavy grades of board, and the Valmet IQ moisturizer is the key tool in keeping them satisfied,” says Tomasz Zamczala, Production Manager (right). “The moisturizer has enabled us to expand our product offering and today, ten percent of production is heavier grades.”
“Compared to before, we are more flexible, we generate less waste, and we utilize a higher machine speed, resulting in more production – a pretty good outcome,” he concludes.