Slitting and rewinding
The reinvention of rewinding By Jordi Prat, technical sales director, slitting, Comexi
• Versatility and ease of use • Cost-eff ectiveness
• Well suited to duplex and turret machines focused on high throughput
F
or decades, fl exible packaging converters have faced an unresolved trade-off : rewind with high quality, or rewind with high productivity. The solutions available on the market forced manufacturers to sacrifi ce one for the other. But can that compromise be removed entirely?
THE TWO REWINDING SYSTEMS: ADVANTAGES AND LIMITATIONS First it is worth reviewing the two rewinding methods that have defi ned the industry up to now.
CENTRE WINDER
In this system, only the rewinding shaft is motorised, while the lay-on or contact roller remains free. It is the most widely adopted method in the fl exible packaging industry, and its prevalence refl ects clear operational advantages:
However, roll quality is not always optimal. The resulting reel can suff er from fl exing that aff ects the fi nal product profi le, particularly with sensitive substrates or at high operating speeds.
CENTRE-SURFACE WINDER
This system motorises both the rewinding shaft and the lay-on roller. Its main advantage is a constant rewinding point — the distance between the cut and the winding point remains uniform throughout the entire process. This translates into: • Greater material stability during processing • Prevention of reel fl exing through continuous lay-on roller support
• Superior quality and a more consistent roll profi le The centre-surface system has long been considered the quality benchmark for primary machines. However, its adoption in high-production environments was historically limited, as roll changes were perceived to be slower — penalising throughput. As a result, the market gravitated
toward centre winding to maximise output, even at the cost of roll quality.
This dilemma means manufacturers need to choose between a high-quality reel and a high- output line.
Drawing on direct experience with end users and deep knowledge of the fl exible packaging market, Comexi has developed the advanced linear winding system (ALWS): a system that replicates the behaviour of centre-surface rewinding while eliminating its productivity drawbacks.
WHAT DOES THE ALWS MEAN FOR FLEXIBLE PACKAGING CONVERTERS?
For production managers and operators working with sensitive substrates, tight tolerances, or demanding customer specifi cations, this translates into concrete operational advantages: • Less waste from reels with a defective profi le • Greater consistency across shifts and operators • Flexibility to run in duplex or turret mode without compromising the quality standards of a primary machine
• Production speeds comparable to the highest- throughput solutions on the market
48
May/June 2026
www.convertermag.com
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