Bags of potential

With time to market invariably at a premium for even the most basic of commodity items, the pressure is very much on the packer filler to ensure that increasingly tight delivery schedules are met efficiently and cost-effectively.

Lacking the glamour and pizzazz of on-shelf impact though it might be, a smoothly running production line is nonetheless as critical a contributor to achieving margin as any text and graphics generated point of differentiation.

Vertical form fill seal systems (VFFS) are a manufacturing staple: the tried and tested engineering means through which billions of bags and pouches have been produced worldwide on a daily basis for the past 75 years. Familiarity, however, does not preclude scope for innovation and in consequence, improved performance - not just in terms of speed, but in the versatility to extend the technology's reach; no more so than for fresh produce applications, says Bosch Packaging Technology product manager Robert van Mol.

"Today's selective consumers do not just want their food to be fresh; they want it to be fresh for longer, with greater usability," he states. "This places complex requirements on food manufacturers and packagers, and presents an array of challenges. Packaging machinery suppliers must ensure that their packaging lines provide the speed to bring products to market quickly. And, with regard to fresh food packaging, we expect to see particular development in two areas: convenience and food safety and hygiene.

Expectations are that the most successful fresh food brands in the future will be those that are "convenient, tasty, environmentally friendly and offer health benefits", says van Mol. "With a growing number of food products intended to be eaten with minimal preparation time, packages of already assembled freshly cut salads and single packets of vegetables will become more and more common," he says.

"Hygiene and product integrity are of paramount importance to today's food shoppers, and exert an increasingly apparent influence on purchasing decisions. Modern fresh food packaging has to reflect this trend by helping to extend shelf life and prevent contamination," he concludes.

Specifically geared to meet these criteria are Bosch's servo-powered, modular and tool-less changeover enabled SVE and SVI continuous and intermittent motion VFFS machines, respectively, that are easily integrated into packaging lines; both offering the flexibility at speed to handle a wide range of formats such as pillow, gusseted, block-bottom, doy-style and corner-sealed bags, via a simple change to the forming set.

For example, the SVI 2620 system can output 120 bags/min operating up to a maximum width of 260mm.

The seal of success

Product integrity of fresh foods is aided by the integration of machines that use ultrasonic sealing - for example, Bosch's SVE 3615 LR - and through lines which allow for economically efficient product protection methods, says van Mol, as by using vibrations (rather than the customary heating method) to create a hermetic seal, it avoids exposing products such as cheese and lettuce to high temperatures and largely eliminates damage and risk of contamination. It has the added benefit of restricting food particles from the sealing area.

High volume production

While heat-sealing accounts for around 85% of all food packaging applications, with raised awareness amongst consumers of food safety, the more expensive but equally more reliable ultrasonic option may be poised to realize increased adoption, according to Herrmann Ultrasonics CEO Thomas Herrmann.

"Although the cost of an ultrasonic sealing station can be four times as much as for a heat bar, once it's been retrofitted the viability of the seals is pretty much 100% guaranteed, whereas the failure rate on heat-sealed applications can be as high as one per ten thousand," Herrman argues.

Italy-based PFM Packaging Machinery has developed a new rotary sealing jaw technology to allow gas-tight hermetic seals to be achieved reliably at elevated speeds on its Supernova modified atmosphere (MAP) VFFS bagging machine launched in Q4 2011.

The Supernova incorporates a gear-based cam system in place of the usual springs that hold the sealing bars against the film for the required period.

Capable of producing MAP packs at speeds up to 250/min (40% greater than its predecessor), the Supernova is aimed at high volume food products such as cheese, pasta, snacks and bakery items that require extended shelf life.

More recently, PFM has been targeting the stand-up bag and pouch market with its new high speed Solaris VFFS machine equipped with a "revolutionary" lightweight, long dwell box-motion sealing jaw able to reciprocate at elevated speeds without risk of vibration, and to give output claimed to be 50-100% higher than existing machinery.

This means speeds of 100 block bottom bags or 90 Steelo four-corner-seal packs/min, or more than 200 conventional pillow packs/min.

In PFM's Steelo bag format - which by taking up almost 15% less space than conventional pillow packs is said to save both transit packaging cost and supermarket shelf space - the corners are heat-sealed for 5-7mm in from the edge, to improve both rigidity and appearance to the point where powdered products such as desserts can be packed without a carton.

The vertical seal of the bag is also incorporated in one of the corners, presenting the opportunity for all-round, uninterrupted graphics.

A further innovation from PFM is the Zenith Duo Bag VFFS machine, which is capable of creating stand-up four-corner sealed bags with an additional pocket - to hold promotional items or accessories - from a single web of film.

Typical applications for this system are snacks such as cheese and processed meat with their own cutlery and wipes; confectionery promotions with giveaways or toys; and pasta with sachets of spices or flavoring.

The bag is based on the Steelo bag format but with a fifth panel sealed into place at the rear to form the pocket.

Continuous improvement

Innovative double rotary jaw motion and superior control technology is a feature of Ishida Europe's new Atlas-122. The machine's accurate film registration is claimed to ensure wrinkle-free tight seals at a production speed of up to 250 bags/min.

The Atlas-122 system also offers effective product charge control, which reliably strips any remaining product from the seal area and prevents product from being blown upward.

"Atlas bag makers have been designed to enable our customers to squeeze the last remaining drops of efficiency out of their snack food packing lines (to reach production efficiency rates of close to 100%) while offering perfect pack quality and minimum waste of both product and film," says Ishida Europe marketing manager Torsten Giese.

Bags of potential

Also exemplifying the potential of a double jaw configuration is Australia-based Tna, whose newly-launched FXIS 3ci extension to its market-leading Robag range is claimed to be the world's first VFFS rotary polyethylene (PE) packaging system.

Outputting at rates of 150 bags/min - double the throughput in comparison with standard single jaw packaging systems currently on the market - the 3ci's innovative rotary jaw design uses advanced impulse sealing technology to deliver high quality, consistent packaging with high levels of accuracy. Product waste is reduced due to the optimized product transfer from the multi-head scale through to the jaws, according to Tna.

The 3ci builds on the established features of the Robag series, including the simplified film threading system and stainless steel construction for ease of cleaning, while also delivering efficient, reliable PE sealing and bagging for numerous packaging applications such as fresh or frozen vegetables, salads, ready to eat fruit, and pre-wrapped confectionery.

"It's a truly ground-breaking addition to our existing innovative packaging portfolio, and expands our capabilities to an even wider range of applications," says Tna MD Michael Green.

The Robag series incorporates a patented stripper device that prevents particles from reaching the sealing area; the net result being a significant reduction of leaks that can easily impact upon both quality and shelf-life.

According to Zvonko Popovic, CEO at leading Croatian savory snack producer Kanaan, it's a feature that recently led to the company installing two 3c baggers at the end of its potato chip and extrusion snack production lines, with a consequent uplift of 30% in speed and capacity.

"We knew that stickiness and product particles were part and parcel of the potato crisps, extruded snack and popcorn products we process," says Popovic. "However, we also knew that we wanted to achieve higher rates of output and improve accuracy, as wasted bags and packaging film are a costly affair. This solution fitted our needs perfectly."

US vertical form, fill & seal machinery specialist Matrix Packaging Machinery has also been improving the viability of its sealing technology through the introduction of its patented SmartGate product concentrator, which can double the outputting norm for narrow width bags (below 90mm) to 120 units/min according to the technology's co-developer, Michael Krummey.

"Smaller bags are harder to run at high speeds because the product is typically too spread out," he says. "Because of their limited content volume, they are already difficult for a contract packager or brand owner to make much money on.

"By concentrating the food and thereby reducing the time it takes for a total charge of food to be packed in a narrow bag by close to 70%, the application of the SmartGate concentrator results in bags with a higher percentage of in-specification seals (fewer open bags) and frees up operations personnel to spend less time on problem solving and more time on value-adding activities."