Going with the flow

Flow-wrapping was first developed in the US just over 40 years ago to provide an economic means of primary packaging but, since the mid 80s, the skeleton of the average machine has changed little.

Autowrappers sales director Gordon Bell told me that retail pressures have resulted in production lines where labour costs have to be minimised.

This pressure has resulted in the use of servo motors and more automation, particularly where controls and self-diagnostics are concerned. Speed, simplicity, machine repeatability and flexibility is the key to today's successful production lines.

No man has to think for himself these days. Independent variable speed controls and simple mechanical adjustments facilitate minimum product changeover times on mechanical machines. On machines equipped with servos, of course, they are instantaneous.

The Windows interface and product memory offered by the PC minimises set-up time, simplifies machine operation, provides on-screen statistics and streamlines communications with management information systems and diagnostics that simplify the wrapping process.

Important standard features such as 'no-product-no-bag' and 'misplaced product detection' minimise film waste and product damage. With these the user just loads in the password, calls up the product and adjustments are automatically made. Many machines are equipped with gas flushing systems.

Forming boxes, of course, are either fixed or adjustable. Fixed systems are suitable for high production speeds but adjustable breeds are essential where frequent product change is evident and a bag is required more than a tight pack. Autowrappers use dedicated forming boxes in order to maintain quality of wrap. Production speeds can range from 70-600 packs/min, dependent on discipline, machine, product and gauge of wrapping material, which is usually PP these days.

One aspect that is variable concerns the supply of PP film, which can be taken either from the top or the bottom, dependent on the machine used and the product to be handled. Both disciplines have their protagonists. Some use the former for the wrapping of bakery products and products which are difficult to slide.

La Mexicana Quality Foods has raised wrapping throughput for tortillas produced at its Aylesbury bakery with the installation of two Fuji Alpha 5 Jumbo flow-wrappers that allow sticky products to be handled at high speed.

The two Fuji machines, supplied by Paramount Packaging Systems, are bottom reel flow-wrappers, with the film unwinding onto the machine bed to carry stacks of tortillas through the pack forming and sealing process, without risk of dragging against metal components and destabilising the stack.

"Some of the tortillas are quite sticky and so, immediately after the stack had been delivered by the infeed peg, the bottom tortilla could stick while those above would be carried forward by the film above," explains La Mexicana factory manager Phil Wilcock.

"With these new bottom reel Fuji flow-wrappers, the entire stack always moves at the same speed since there is no friction and rejects have gone down quite dramatically."

"Autowrappers favour film supply from the top as web control is better and most products can be fed with new infeed developments that overcome the need for top seal machines," comments Gordon Bell.

"Not unnaturally, one of the most profitable markets in this business can be found in the food sector. We are predominantly involved in the biscuit, bakery and confectionery sectors.

"We have seen an increase in bakery applications due to the need to automate products that a few years ago we would not have considered. We are producing complete lines with our sister company Turbo Systems.

"Over the past year we have supplied lines for cutting, injecting and wrapping garlic bread, totally automated a crumpet line and a line for feeding and wrapping scones." On the other hand confectionery sales in the UK have dipped by 2-3% in the last year. Nestle puts it down to kids buying mobile phone top up cards.

So what does the future hold for flow wrapping? To some extent it depends what country you live and work in. In Japan, for instance, everything in sight is flow-wrapped, primarily for product protection but also for pilfer-proofing. This trend will never come to Europe, if only because of the waste legislation that has and is being imposed.

Multiple machines are becoming popular to wrap products like phone cards. Indeed, Autowrappers machines are doing the job at 300 packs/min and then packed again in 10s or 20s. Secondary packaging is becoming far more important, particularly where product security is high. In these instances feeding and counting systems are being finessed.

For some time cold-seal materials have cornered the market but now that heat-seal products run at much higher speeds, there should be some change here. Cost is being driven down but not at the expense of productivity and efficiency.

Multi-lane machines have been around for some years and are also being considered for the future but there is a lack of demand, presumably because of cost and the lack of efficiency at the present.

The immediate future lies in more complex feeding and handling operations. Cleaning and product changeovers are also key issues and more and more customers are interested in storage and buffering of products.

Walkers Charnwood, one of only a few bakeries in the UK to specialise in the production of Melton Mowbray pork pies, recently installed one of Rose Forgrove's Minerva PC Flowpak flow-wrappers to upgrade their automated multi-packaging operation.

The Minerva PC, supplied with an extended product in-feed system, is being utilised to pack mini and buffet pork pies in tray-mounted batches of six and 12 in printed and coded PP pillow packs for major supermarket chains.

While there has been no reason to use the modem facility, the remote diagnostics value offered by the PC controls is said to permit software upgrades and other activities to be performed in an efficient and cost-effective manner.

Equipped with an extended product in-feed system, the Minerva PC receives a constant supply of pre-formed card trays that are then packed with pies.

Wrapid has launched the Pfankuch VP-655 that has been specifically designed for the stationery, publishing, printing and education sectors. It is suitable for wrapping items up to 15mm in thickness such as greeting cards, leaflets and labels.

Features include a pneumatic sealing head and a top cycle speed of up to 120 packs/min. The sealing jaw allows cross-sealing of packs, providing an even tighter wrap.

   Operationally, the machine utilises two separate rolls of film, said to ensure seamless packs. This innovation allows the use, where appropriate, of two different films.

Typical combinations could include metallic bottom film and printed top film. Through the utilisation of different films significant cost savings and flexibility is achieved over conventional single films together with a more professional finish.

CSS Packaging Machinery, in association with Tyrrell Engineering, make the Sprinter Junior hffs machine, which is suited to a range of flow wrap packaging applications including bakery and pastry products, fruit and vegetables, trays, confectionery, cheese and non-food products.

It is fitted with an adjustable fold box, a 2m infeed conveyor and an end crimp carry over conveyor. It is also available in either electronic or mechanical versions and requires only a single-phase electrical supply.

An entry-level flow-wrapper – built in balcony style for hygiene and ease of cleaning – is now available from Sussex & Berkshire Machinery.

Built in Italy by Schib Packaging, the CO100 is made in painted steel or stainless steel [IP65] versions, with all motors, drives and electronics housed in a cabinet at the rear of the machine.

The CO100 offers speeds up to 200 items/min, depending on length, and will handle products up to 250mm wide, 120mm high and 530mm long. Minimum product length is 60mm.