Ultrasonic comes of age

Ultrasonic comes of age

ILAPAK UK estimates that one third of all VFFS (vertical form fill seal) packaging machines in the salad and cut leaf industry field are now equipped with ultrasonics, and predicts that this figure will rise as fresh produce packers upgrade their lines and replace old equipment.
Ultrasonics has the ability to improve seal integrity whilst delivering benefits for the environment. Now, falling equipment costs, quicker payback and advancements on bag styles and films are all conspiring to make the technology an increasingly attractive proposition for the mass market.
In tests, ILAPAK has produced doy packs with ultrasonic seals. This is an industry first and a massive breakthrough for a technology that, until now, has been limited to basic pillow packs. Gusseted bags are particularly prone to leaky seals, making them ideal candidates for ultrasonics. The challenge is that gusseted bags have a variation in thickness in the seal area that makes them more complex to seal ultrasonically. ILAPAK has devised a way of applying ultrasonics to gusseted bags and hopes to roll out this functionality to the marketplace in the near future as an option on its VT (Vegatronic) 6000 bagmaker.
ILAPAK’s latest generation of VT vertical bagmakers is far more versatile than its predecessors and many of its competiors in not only the variety of bag styles but also the variety of films it is able to seal ultrasonically. Whilst first generation machines were only designed to run OPP, ILAPAK’s newest models can seal everything from laminated films to PE and LDPE films.
Another factor driving uptake of ultrasonics is that the overall COO (cost of ownership) of ultrasonic systems is gradually falling as both the upfront capital outlay and the associated maintenance costs are lower than they were. The price tag of ultrasonic machines has fallen as the technology has ‘bedded in’, whilst the reduced maintenance requirement is a result of refinements to machine design; in the early days, wear parts such as bearings needed replacing far more often than on heat seal machines. Heavy duty framework and reinforcements around the sealing jaw mechanisms enable the latest generation of bag makers to stand up to the rigours of ultrasonic sealing. The overriding reason for investing in ultrasonics is to eliminate leaky seals. Unlike conventional heat sealing methods, ultrasonics can seal through any leaves which may have accidentally been deposited in the seal area and this leads to huge advantages. Producers can reduce their reject rate from an industry average of 5 to 10% to less than 1%. This functionality, coupled with the superior seal strength that can be achieved with ultrasonics, means salad producers can expect great savings in labour and film costs thanks to the lower rework rate they will get from switching to the technology.
Besides slashing leaky bag rates, ultrasonics is a green technology; it yields film savings of up to 20% owing to a narrower seal area, and energy savings of up to 30% compared to traditional heat seal technology.
There are other benefits to using ultrasonic sealing too: since the tools used to create the seal are cold, there is no risk of damage to product as there is with hot sealing jaws. What’s more, film doesn’t stick to the sealing jaws in the same way as it can with hot sealing jaws, reducing downtime for cleaning. Producers can run VFFS ultrasonic machines at a significantly higher speed than traditional baggers with a heat seal system. Getting a proper separation between two consecutive dumps from the weigher is no longer an issue with the new ultrasonic sealing system and the overall cycle time can be reduced.
ILAPAK was one of the pioneers of ultrasonic sealing, and its versatile VT 6000 bagger has become a reference for the salad industry, owing to its ultra-hygienic construction and fast changeover capabilities. Operating at speeds of up to 80 cycles per minute thanks to digital servo drives, the continuous motion bagger can produce packs of up to 300mm in width from virtually any film. Open frame design allows the operator to seethrough the machine to view the film path and alignment and complete IP65 protection enables full wash down capability.
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Stephanie Cornwall
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