Aetna chairman Barry Tucker gives his thoughts on 30 years of stretch wrapping development and emphasises how important it is to choose the right machine and supplier for what is one of the most critical end-of-line operations

In the beginning [the 60s] there was polyethylene. Shrink film closely followed and in the mid 70s stretch film made its entrance. Initially, there was not too much stretch with either PVC or its co-laminates but its introduction led to the first use of hand wrap films, largely replacing steel strapping or twine for securing pallet loads.

The rapid growth in the use of pallets and the dynamic development of ‘logistics’ over the past 20 years has brought about a huge use of palletising and pallets and, of course, pallet load stretch wrapping machinery.

Early pioneers were Lantec in the USA and here in the UK Inpack led the way with the introduction of semi-automatic rotary turntable systems. By the early 80s Inpack had introduced a range of fully automatic machinery which included a four-legged rotary arm system that was able to fully wrap a pallet load of product at a speed up to 60 pallets/hr.

The Inpack production unit has long since gone but in the early 80s the first ring system entered the UK, designed and developed by Haloila in Finland.

These new systems caught the imagination of some of the specifying engineers largely working within the food and drink industry.

The system, which rotated a film reel on a ring that traversed up and down the height of the pallet load [obtaining its power for the film carriage from slip rings], was perceived to be less complex than the rotary arm systems. In any case it rotated faster. This met demands for increased wrapping speeds.

The introduction of the ‘ring’ system led to the sale of some 15 units a year under the Mancon banner through the 80s. In the late 80s and with the acquisition of Newtec, who had already acquired Inpack, and Haloila, ITW became responsible for the production and sale of the Haloila ring system into the UK. In principle the same system is offered by Signode, also part of the ITW Group.

In the early 80s LLDPE Mobil first introduced stretch film and this moved all stretch wrapping technology forward. Performance became more reliable and film stretch up to 200% was available while running at high speeds.

Since then, stretch films have continued to be improved and, today, BPI are producing cast films which, at 23 micron, are able to provide reliable pre-stretch up to 300% in some cases at the very highest speeds on the more sophisticated wrappers. These films have been developed to also provide those other necessary properties of good load holding and puncture resistance.

Power pre-stretch became the buzz words and several manufacturers including Lantec, Robopac and Mancon developed systems to apply the film at high speeds using accurate lay-on force to avoid crushing or distortion of the goods in the pallet load.

Subsequently, Robopac developed its ring system in 1997 and the Mancon system was acquired by United Packaging towards the end of the 90s.

The UK market has a varied choice of pallet wrapping systems, many of which continue to be developed.

From simple rotary turntables up through bridge rotary arm, to four-legged rotary arm and on into the various ring systems.

Other developments include film tail-sealing systems, fully automatic reel placing systems which operate while the wrapper is in action, top sheeters which can also be located onto the pallet top while in operation, and top sheet roll placers.

Massive improvements in software provide an increasing ability to communicate and control the function of the line and maximise the efficiency of the line into and through the palletiser and on into the warehouse.

Never before has pallet wrapping been more important to the efficiency of a production line and, gradually, industry is coming to realise this. Gone are the days when a line went in and the stretch wrapper was put in as an afterthought. Gone are the days when a production operator or supervisor did not know the make of wrapper on the end of his line.

The manufacturers of ring systems have tried different types of material for the ring and at this time there are carbon fibre, aluminium and steel rings in use.

Robopac moved away from the traditional slip rings to provide energy for the power pre-stretch and developed a patented dynamo system that generates sufficient energy to drive their pre-stretch unit. This is trouble-free and sometimes preferred in environments where there is a lot of dust or sugar in the air.

There has been a great deal of education and learning over the past 10 years and engineers and production management have come to realise just how important the choice of pallet stretch wrapper can be.

Because of the improvements in film quality and abilities, wrapping speeds have increased over the years in line with production demands and the highest speed systems, which are ‘ring’ capable of 50rpm, are now able to produce up to 90 fully wrapped pallet loads/hr for a 2800mm high load.

There are examples of ‘ring’ systems wrapping loads at speeds up to 120/hr in the case of a major plastics drum manufacturer. With the recent introduction of dollies, particularly in the drinks industry where wrapping speeds were doubled, there came the need to wrap at 115-pallet loads/hr. This was achieved and the system is running well.

Clearly, at these speeds the software abilities are critical and the fine tuning required is very much down to the experience and ability of the manufacturers.

With all the technology concentrated on higher speeds, more economic use of film and optimum wrapping, it is strange that the UK remains a major user of hand wrap films.

It probably uses the highest tonnage of hand wrap stretch film in Europe. At this level, it is not only expensive but also produces a poor wrap which provides very little real support or protection and flies in the face of health and safety regulations. All those with bad backs and unnecessary strain will continue to be reminded of this.

For these reasons it is clear there is still major growth ahead into semi automatic pallet wrapping and, across the whole spectrum of British manufacture, there is a gradual movement from semi- to fully auto-operation.

The major suppliers have all noticed a trend toward systems and automation, moving production down to a single automatic wrapper rather than several lines each feeding semi-automatic systems with all the handling that is required. As a result many of the orders being placed tend to be for systems.

This trend makes it more important for the major suppliers to provide advice and consultancy to ensure their investment is maximised. It is in this area that the most experienced in both purchase and supply will continue to occupy a major sector of the market. Service and support is also essential to the cost-effective use of a pallet stretch wrapping system.

As technology continues to improve the effectiveness of the leading wrappers, the range of methods available to suit production speeds, layout and preference continue to proliferate and more and more these days specifying engineers are able to choose the ‘right’ wrapper for the job. It is not always necessary to specify a ‘ring’ system when the rotary arm will comfortably do the job.

A number of major manufacturers in the UK who adopted the ‘ring’ system in the 80s have more recently settled for other systems as an acceptable alternative. Never before has there been such an acceptance of the specifying philosophy of horses for courses.

I have only dwelt on the aspects of the use of stretch film for pallet load wrapping but there are, of course, many other areas where, in recent times, other products have been able to take full advantage.

One example is horizontal stretch wrapping where bundles of metal, plastics or wood with varying lengths and diameters have been bound together horizontally.

Two or three suppliers have dominated this market over the past 15 years and these horizontal rings are now produced with diameters up to 3m.

This enables flat pack furniture, for example and even plaster boards to be wrapped automatically.

One recent installation incorporates a complete handling system for boards as long at 3600mm, 1220mm wide and 1200mm high – an enormous pack handled automatically. This installation brought about considerable savings and the wrap is just as effective as the previous method.

In this area films have been improved to produce a ‘slip’ ability on the outer surface so that products such as doors when wrapped and stacked in a retail outlet are able to slide out.

Many of these products were previously packed in corrugated board and, in the case of metal cabinets, it has shown that when film is wrapped more care is taken in handling. One of the largest manufacturers of office equipment in the UK saw a significant reduction in damage when changing from corrugated to film protection.

Another trend that is affecting us all is that towards single source supply. Fewer specifying engineers has brought this about and with it the need for end of line systems experience. More care when selecting your supplier.

Outsourcing the supply of machines and relying on others to maintain and support the machinery, supply the film and, in exchange, pay for pallets on the floor is not a bad idea. If it is possible with the right machine to wrap your pallet for 12p, it is important to ask yourself whether the costs add up?

Machine leasing is always an option and, providing care is taken in choosing the supplier and genuine service is available locally then there probably are better alternatives.

Environmentally, stretch film offers positives rather than negatives and, if incineration is the future for waste, there is a need for inflammable materials to complete the task.

Looking ahead there will be a steady growth of stretch film, particularly over the next 10 years.