Q&A on Slitting and Rewinding
Michael Pappas, president of Catbridge Machinery, has held his position in the industry for 10 years and has the answers to prove it.
FP: What's new and exciting at Catbridge?Pappas: We are presently working on refining a new model slitter, one that we expect will revolutionize slitting departments. This model, already in use on films, can out produce conventional slitters nearly 3 to 1. This helps companies in need of floor space get dramatically more through their slitting departments in the same, or even less area.
Ease of operation in the form of quick set-ups between and during jobs greatly increases productivity and reduces operator fatigue. Simplicity of core loading and finished roll discharge also reduces cycle time and presents finished rolls in a way as to be more rapidly oriented to a wide variety of downstream labeling and packaging steps. Pricing will be no more than other conventional winders on the market today making it a great value to companies small to large.
FP: What factors must be considered for proper slitting/rewinding?Pappas: The usuals of course, materials, slit width, type of slitting, unwind and rewind roll weights and tensions. These are the initial factors that begin to point us in the right design direction.
Other layers of consideration follow, including slit widths, speeds, and other features/functions needed between the unwind and rewind such as lasers, perforation, cameras and splicing. And, job mix is a very important consideration. How long does a job run (number of sets), how often are set-ups changed during a shift, etc.? These are critical to designing not just a machine that will do the job, but one that is right for the work.
FP: What kind of problems can occur with improper slitting/rewinding?Pappas: There are two basic types of problems, visual and non-visual. Visual defects include poor edge quality, core alignment, telescoping, “starring” at the core, among others.
Non-visual problems are centered mainly on poor tension control. The results manifest as hard and soft rolls, and rolls would with too much tension can, over time, crush a core, cause “edge ooze” on adhesive coated substrates and run inconsistently on packaging machines. Consistent tension control across the web, and throughout the build on each individual roll is critical.
FP: How would you characterize this market?Pappas: In a word, dynamic, across a number of levels. First, no industry we serve has faster changing, more consumer-driven products than flexible packaging. Almost monthly innovations in packaging materials and processes dictate new and better materials from converters. The challenges trickle down quickly to machine builders. More precise, more efficient and faster labor saving machinery is required.
Also, growth overall, combined with little consolidation in recent years, have companies scrambling to update machinery and processes. This presents demands and challenges for machine builders. The focus must be on not just today’s products and features, but in anticipation of tomorrow’s as well.
FP: What kinds of trends/technologies is the slitting/rewinding sector seeing?Pappas: In the last few years there is a clear trend toward focus on two areas: First, reducing downtime between sets. We have done studies for our customers, and regularly assist them in collecting data to tell us both what percentage of a shift their slitters are actually running, versus the percentage they are down between sets (for roll changes, set-up changes, core placement, etc.). The average we have found is in the 25 percent to 35 percent range. This must be improved.
Also, as slitter speeds and uptimes increase, more rolls are coming off and the problem becomes what to do with them. They must be removed from the slitter quickly but also in a way that facilitates ease of packing and minimizes operator time and fatigue. These are challenging areas.
FP: What are Catbridge's customers requesting?Pappas: A number of things. Generally, better roll quality to accommodate even faster packaging machinery and faster slitting speeds for more throughput remain standards of the normal focus. But today, there is increasing focus on more throughput via reduction of downtime between sets, flexibility – the ability for one machine to handle a broad spectrum of jobs – and adaptable machine designs to allow additional features for new work that may come in the future.
FP: Do you see anything missing in this portion of the flexible packaging industry?Pappas: Yes, in the area of roll presentation for packaging. A better word than missing might be “evolving”. As slitters become faster and cycle times shorter, production challenges naturally shift to the packaging part of the process.
The challenge becomes getting rolls away from the slitter quickly and in such an orientation as to allow any labeling that need to be done quickly, and the rolls then presented in an optimal position for packaging. This is especially challenging in flexible packaging where there are a wide variety of packaging methods and requirements. Converters must often be ready to bag and box, shrink wrap, place on a skid with liners between rolls, place in boxes, etc. An integrated and very versatile system of roll discharge and packaging is a challenge and is quickly becoming the focus.