Several years ago, a major producer of printed paper bags was struggling with poor edge quality. The edge on rolls being provided by the company’s supplier wasn’t consistent enough to print close to it without trimming, and the rudimentary trim system that came with the machine delivered poor cut quality. It was a simple blade rotating at the speed of the web without enough control or stability. Operators couldn’t get consistent results when print needed to bleed to the edge of the paper. When they tried to print close to the edge, they would end up with messy ink on their rollers and excessive material waste due to unacceptable finished bags.

 

Precise edge trimming was the key to ensuring that words and images would not be cut off or folded over when the paper was trimmed, glued, and formed into paper bags. The company needed a solution that would guarantee dependable edge quality for all of the paper grades that they run (30 – 100 point).

Mario Cotta’s “Kobe” edge trim system was the solution. The Kobe is specifically designed for trimming edges of continuously moving webs with a motor-driven bottom knife assembly. The system features pneumatic upper knife holders for shear cut precision. The Maintenance Manager at the plant explained that they invested in the first system as a test. The test went so well that they have since purchased ten systems, and plan to buy many more. “Ultimately”, he explained, “every line in the plant will run with the same system.”

In addition to solving the edge quality problem, the Kobe systems have also allowed the company to increase their line speeds and improve throughput. The blades on the knife holders last a long time and maintenance on the system is rare. The Maintenance Manager at this particular plant chose the manual positioning model with digitally-assisted rack and pinion postioning, but motorized digital positioning and fully automatic positioning systems are also available.

 

For more information, please contact Double E Company, the exclusive distributor of Mario Cotta slitting equipment in North America.

Mario Cotta's "Kobe" edge trim system provides a consistent, high-quality shear cut.

 

"Kobe" edge trim system viewed from the side as the web material passes through.

 

"Kobe" edge trim system shown with "PPS" style shear-cut knife holders - as used by the converter in the case study.