Equipment: Strap-wrappers

Combi or monobloc systems are a tried and tested way of integrating two or more packaging operations to save line space and cut costs. But while such systems are commonplace for combining functions like metal detection and checkweighing or filling and capping they are rarely used for joining up end-of-line packing operations like pallet strapping and wrapping.

Some pallet loads only need either strapping or wrapping, while others require both – for example, for stability and protection from dust or rain. So where companies deploy both methods of load protection, does it make sense to use a combi machine?

Combination strapper-wrappers do exist but they are not exactly commonplace. Wulftec says it builds dual systems that integrate both strapping and stretch wrapping when such an application is needed. Cyklop, meanwhile, actively markets a hybrid machine called the TwinPack. The machine combines two Cyklop systems – the GL 215 stretch wrapper and the XP 112-MVB strapper – enabling them to be centrally controlled. Various different packing combinations can be achieved, including economical, normal and rainproof wraps, as well as two parallel cross straps, two parallel lengthwise straps and both cross and lengthwise straps.

“The irritating manual strapping and sealing disappear,” says regional sales manager Steve Merricks. “The pallet is placed on the turntable and the strapping cycle is started by push button. The machine automatically straps the load according to the pre-selection.”

Strapping is usually carried out first because wrapping covers the pallet void – the area through which the strap is fed. Merricks says the main reason companies opt for the TwinPack is to give them the flexibility to automate both functions on a small footprint. “The last one we sold was to a company manufacturing car parts,” he says. “The reason they bought it was some of their products they wrapped, and some they hand strapped. It gives them the option to automate both operations.”

Besides occupying less floor space than two stand-alone systems, the TwinPack is also said to be more time-efficient. “Valuable time is saved due to automation in this area,” says Merricks. “The operator only moves the pallet once, so the number of secured pallets per hour rises considerably.”

Cutting costs
In addition, it is cheaper than buying separate machines. Merricks estimates buyers can save £12,000 by opting for a combi system. Strapping equipment supplier Mosca Direct says the savings could be even greater – managing director Peter Foster estimates the price of a combination machine at around £50,000 and the price of an automated line at between £110,000 and £200,000. But despite all these advantages, companies aren’t exactly clamouring to buy combi systems. Merricks admits: “I’d be lying if I said we sold thousands. At the moment we sell one or two a year.”

Mosca’s Foster believes that one reason combi machines aren’t that popular is because they usually still require some operator invention, whereas separate systems linked by conveyors can be completely operator-free.

“The operation of these machines is semi-automatic from the point of view that they would not be part of a totally operator-less line as separate machines could,” says Foster. “The essential problem is that because the wrapper is inside the strapper, it’s not as flexible or as sophisticated – there is generally only one lance (strapping position) so a turntable is needed, and an operator is needed to ensure that unusual pallet sizes turn correctly. Also, the film-cutting mechanism tends not to be as sophisticated, which also leans towards this becoming a manual operation.”

The upshot of this is that throughput speeds are only around 12 to 15 pallets per hour, according to Foster. By contrast, a line consisting of stand-alone systems linked by conveyors could be capable of up to 130 pallets per hour for a two parallel strapped pallet and up to 65 pallets per hour for a four-way cross-strapped pallet.

He says that potentially, an automated system is feasible but not commercially viable – it would cost more than buyers would be willing to pay.

“Generally, combi systems are used by companies who need to save space, and are low throughput, low budget operations. It’s all about the output-to-cost ratio, and those who can afford automation would probably opt for separate strapper and wrapper rather than a combi.”

This explains why, rather than developing combined strapper-wrappers, Mosca has been busy working on its SoniXs ultrasonic sealing technology.

“Ultrasonic sealing is very efficient, with the tensile strength representing 85% of the tensile strength of the strap used,” explains Foster. “As a result, a strap can withstand greater stresses during transportation and it is also possible to use lower cost, narrower or thinner strap material. SoniXs machines are also more economical and produce lower emissions, with practically no fumes or smells produced, and by avoiding heat sealing there is no residue build-up caused by melted strap to dispose of.”

There are varying degrees of integration, and while the Cyklop TwinPack represents total integration, lines made up of separate systems linked by pallet conveyors are another ‘less extreme’ form of integration.

Best of both
As Aetna’s national sales manager Dave Walkinshaw says: “It is possible to integrate stretch-wrapping and strapping systems into the same line and this is something that we have done on several occasions, but it is always done with separate machines linked by a pallet conveyor. It’s not a stretch wrapper that straps or a strapper that stretch wraps.”

He says this is the approach favoured by corrugated packaging suppliers – one of the biggest markets for strapping and stretch wrapping systems. “They have always gone with separate systems, primarily because they can incorporate the exact type of strapper they require with their exact choice of wrapper – there are many different types of both system which suit different products.”

Aetna has recently managed a project at paper manufacturer James Cropper, which included the installation of a combined pallet strapping and stretch-wrapping line. James Cropper manufactures coloured and specialist papers for the stationery, book covering, luxury packaging and industrial paper markets. The volume and variety of its products has meant that historically its packaging activities have always been labour intensive.

To support a volume growth strategy while simultaneously reducing costs, improving quality control and reducing manual handling risks, the company decided to automate the packaging process, and invited several companies to tender for the contract – among them Aetna.

A versatile system was needed to replicate the variety of operations that were being carried out by hand, on pallets that ranged from 600mm square, to 1300mm wide x 1600mm long.

Aetna’s solution – which won the contract – was based on four laser-guided vehicles – one with a clamp attachment to handle reels, and three to handle the palletised materials. It also proposed a fully automated pallet strapping, stretch-wrapping and labelling line, comprising a Mosca compression strapping system, a Robopac Genesis wrapper and a Logopak labeller. Pallets are loaded on to the system with a complete packaging specification, which includes the number and direction of straps to be applied, wrapping pattern with or without top sheet and size of top sheet, and number and position of labels.

Increased efficiency
James Cropper says that since investing in the system, labour costs have been reduced by a third, exposure to manual handling risks has been reduced and its complex order book is handled and packed in minutes and hours, rather than days.

One system which could allow users to get the best of both worlds is the Italian-built Bema stretch-wrapper distributed in the UK by Walsall Engineering. This offers a strapping option using ‘roped’ film.

“The system gets a reel of film and twists it into a rope that can be used for strapping,” explains director Steven Chorley. “You can use this option for pallets that don’t need full wrapping – just simple banding – or you can stretch wrap and for extra strength add a film rope.”

While Walsall Engineering is touting the strapping function as a useful feature, it is not intended as a replacement for strapping. “It’s more of an additional feature – something Bema realised the machine could do because it has a robotic arm.”

WRAPPING AND STRAPPING ROUND-UP
While combining wrappers and strappers is possible, and in some cases a cheaper option, separate units still prove the most popular, and with innovation rife in the sector, it seems they will only strengthen their position.

• At Ipex, the recently launched ROMP-K stand-alone automatic strapping machine will be among the exhibits on Mosca Direct’s stand. Designed for the wholesale distribution sector, the model uses the same sealing head as the ROMP-4, but is said to offer simplified design. Several bundle strappers incorporating ultrasonic sealing will also be on show. These include the versatile SoniXs TRP and the SoniXs TAI (comprising a SoniXs TRI in-strapper and a SoniXs-TR cross-strapper).
• The latest stretch wrapper from Aetna is the Genesis Futura 80. This high-speed system is designed to wrap 130 pallets per hour and give increased pre-stretch film yield, reducing wrapping costs by more than 25% versus existing pre-stretch systems, says Aetna.
• Inpac’s new AP300 is pitched as an entry-level stretch wrapper, but with features that wouldn’t normally be found on basic equipment. The programmable machine allows users to store settings for different pallet loads, saving on film waste.
• Launched last autumn, the STB 70 from Strapex is a hand-held tool which carries out strapping tasks ‘at the touch of a button’.
• Loveshaw Europe has extended its pallet wrapper range with a basic core-brake machine called the Pallet Mate. The wrapper is said to combine simple controls with excellent build quality.

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