Smooth slitting for a seamless package and better production

7 September 2017

While slitting and rewinding equipment might not always be at the forefront of converters minds when balancing the entire process and constantly looking to improve efficiency and costs, innovative improvements and updates mean that they should no longer be an afterthought for those companies seeking to increase production, but also save money and materials. John Fortune takes a closer look into this vital market.

As a core converting process, slitting and rewinding occupies a key part in the foundations of producing a high-quality finished product. Wide machine capabilities, minimal downtime and ensuring that no materials, money or energy are lost, remain the key trends and needs, which is why the equipment manufacturers are concerned with addressing these as a priority.

Modern machines

One user who is familiar with these issues is John Graham, managing director of Arrow Film Converters, a company that provides printed films for the food and drink industry.

“It's imperative not to have a bottleneck for slitting,” he says. “The quality of print and slitting has to be excellent; good is not enough these days, and for that reason we have decommissioned three of our older slitters that were only refurbished a few years ago. We replaced these with state-of- the-art slitter rewinders. While a good profile is imperative, the constant tension on the rewind is equally vital. Customers have increasingly faster packaging lines and machines where, if tensions are not perfect, films will not track or might snap, causing untold problems.”

This raises one of the key issues in slitting and rewinding: speed. Everything is faster, and so machines and systems have to be set up and run as easily as possible. If something does go wrong however, they need to be able to stop the line, fix and restart as quickly as possible in order to keep to these increasingly faster lines and turnaround times. Graham continues by explaining what was done to minimise the impact of inefficiency on the line, “One solution we have found to be successful is to have the slitter and rewinders with the unwind reel on the same side as our rewind reels. This allows the operator to see any joins in the mill reels and be able to slow the machine down without the need to run back and forth to the unwind section. Our machines have laser guides to improve efficiencies and can run at 600m a minute.

“Another area where we are seeing great strides is in material waste reduction, and responsible or sustainable slitting and rewinding. As our customers are constantly pushing to reduce packaging waste, we look to our suppliers to provide us with the tools to keep films as thin as possible. What used to be 20µ­ is now more often 15­ µ or less. Slitters have to be capable of higher speeds, even on relatively short runs, and be able to extract the waste trim at high speeds – even with a 5mm waste trim.”

As to cost, Graham concludes, “During our last round of significant investment a few years ago with our printing presses, we focused heavily on slitting and rewinding. We spent over £4 million and we realised very early on in the process that our existing machines were not the right standard we needed, so we purchased two new machines right then and there. Although it represented about 15% of the full capital costs, it plays such a vital role that we could not have continued to offer the full package we do without this support”.

It's not just the smaller companies that appreciate the advantages of the latest slitting and rewinding capabilities. Major brands like Huggies have seen the value of modern machines' capabilities as its latest Newborn Wipes show. A collaboration between multinational personal care giant Kimberly-Clark and UK packaging manufacturer Skymark has used innovative slitting and rewinding capabilities for a practical reason.

“Our collaboration with Kimberly-Clark for Huggies Newborn Wipes has resulted in a differentiated packaging solution that we're really proud of. We've achieved exactly what we set out to do in terms of the new film technology.” Skymark is well known for its embossed, plain and printed films, and for this project it developed a specially coextruded film that increases opacity and eliminates visibility of the pack contents.

Skymark's director, Paul Neath, explains, “This project saw us overcome some challenging production changes that could not have been achieved without the flexibility and engineering capability of our slitting and rewinding systems. In fact, this collaboration has allowed us to get closer to realising the ability to offer a seamless, multisubstrate brand offering.” Skymark’s investment in the latest large-format slitting machinery was called upon to fulfil the Huggies brief of a tri-layer co-extruded film with a blue inner layer that disguises the pack's contents, keeping the important all-white aesthetic of the Huggies brand and so enhancing its on-shelf appeal.

New developments

Sticking with non-wovens and nappies, another recent development due for launch later this year comes from Web Industries, which has created a large-format spooling (LSF) resource for manufacturers of nappies, feminine pads, medical facemasks, adult incontinence, and related health and hygiene products. The LSF, which will be available in Q4 2017, is said to provide greater yield non-woven and hygienic materials, additional uptime for production equipment and faster speed to market. Included within the proprietary design is state-of-the-art slitting technology and improved web control, as well as handling capabilities for spools of large width that maximise customers’ run time.

The large-scale spooler unwinds, slits to customer specifications, and then precisely rewinds materials onto cores for shipment to consumer goods manufacturers, where the material is fabricated into finished parts or goods. “LFS is gaining popularity among major manufacturers of diapers and other consumer products for the yield and equipment uptime benefits it can deliver,” says Tom Lucas, Web Industries’ project manager who oversees the spoolers construction. “The marketplace is expanding, and there’s more demand for LFS. We can unwind, slit, and wind a lot of spools very quickly.”

Lucas notes that hygiene product manufacturers typically work with his company’s engineers to select the best material based on price and specifications, such as tensile strength, absorption, basis weight, softness and processability, to find the optimum solution. “Selecting the right material is a key consideration for our manufacturer customers. There is a lot to choose from, and we provide experienced assistance in the materials selection process.

We continue to see strong demand for new hygiene products in North America. In this environment, our large-format spools will help increase our customers’ line efficiencies and lower their total cost. Equally important, our investment in additional capacity will allow us to meet their growing market needs and provide exceptional quality with a wide flexibility in materials.”

The company says that, with smaller format spooling, product manufacturers load a smaller quantity of slit material into their production equipment, and then splice and affix incoming rolls as the material plays out. Compared with LFS, this process reportedly wastes material before and after the splice, and can require machinery downtime to complete the transfer.

“A nappy manufacturer might lose 20 nappies during a splice,” Lucas says. “Our new LFS, with its precision slitting and rewinding, provides splices that are useable. This facilitates longer runs between roll changes and, therefore, longer production runs. We can achieve lengths of materials in hundreds of thousands of feet.”

Label manufacturing

Beyond films and pouch packaging, slitting and rewinding plays a vital role in label manufacturing too. OPM Group offers self-adhesive labels and flexible-packaging solutions, including laminates sachets, lidding film and flow wrap, and manufacturing products for many household names. Marketing director Susan Ellison believes that the flexibility of OPM's extensive knowledge of its slitting and rewinding capabilities means that changes can be made to production with very limited downtime. “Usually, very flexible films or laminates are used to form the pack, which allows the bag to be filled with an increased quantity of product when compared with a similarly sized sachet,” she says. “Typically, bags are filled with dry products such as granules, powders or solid items. Our expertise in this area shines with optimum puncture resistance and aroma barrier properties, so products like ground coffee stay in peak condition. Thanks to our high-performance machines, these specific packaging solutions can be delivered at a high-quality, on time, every time.”

Materials management

Delivering quality, affordable and timely services will always guide converter equipment investment. Randy Dunkin, an operator at Cincinnati Converters, explains, “When we consider slitting and rewinding, today’s trends revolve around the increase of yield from materials that need to be thinner. Any abnormality in the base stock can turn into gauge bands, which are difficult for all aspects of converting."

John Walker, owner of Southern Converters, fully agrees, “The main pressure point for us is always to meet the lead times that our customers demand. As we are a part of a larger organisation, we have to ensure that our systems are in place to meet the deadline imposed on us.” As the converting landscape changes, so too will that of service providers.

“We have seen the industry change over the years. Where we were once involved with self-adhesive and PVC products, today a larger part of our conversion is with food packaging companies where, perhaps, the design of their packaging has changed, and they have redundant roll packaging stock that we can slit down to meet the requirements of their new needs. We are always looking to expand the products that are available to our customers. We are constantly testing new ideas to complement our core business.”

Converters have always had to innovate to ensure that they have the services that clients need and the ability to meet specific demands. As markets change, so does the need for slitting or rewinding services.

“There is definitely a bigger push from Asian manufacturers," says Juha Viitala, managing director at Colombier. “Oversupplied goods suffer from price erosion, which leaves relatively less value to be added in the conversion process. Goods shipped in bulk from China often need local reprocessing to match market demands. This often concerns processing material in small volumes in a short period of time.” Demands of brand-partners impact converters' use of slitting and rewinding equipment and associated packaging production processes. We see more manufacturers adopting lean manufacturing practices, which is leading to outsourced reprocessing,” she adds. “We anticipated an increased demand for electronic integration to customer routines and have invested in ERP systems but, so far, surprisingly few are demanding electronic documents or system integration.”

The future of slitting and rewinding services will revolve around specialist services. As brands want to standout from a crowded marketplace, they will leverage the power of innovative converting solutions. This will lead to more niche markets and specialist demands being placed on converting service providers. When slitting or rewinding components are needed, only agile service providers will become market leaders and enjoy profitable and sustainable businesses.

The capabilities of modern slitter rewinders allow companies to save money and energy while creating top-quality products quickly.
Modern slitting and rewinding equipment has allowed Huggies to create a differentiated packaging solutions.

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