The need to maximise production throughput and efficiencies in the food industry is vital, and weighing systems are playing a pivotal role in the development of fully integrated automated packaging and packing lines. New equipment must be capable of handling all types of products as well as having the ability to link effectively with other systems in order to provide a complete weighing and packing operation.
There are two main 'legs' to developments in this sector: the ability to handle a wide range of products, and the need to integrate with diverse operations -- weighing among them -- on the line. The underlying trend that has resulted in such developments has been increasing emphasis on pre-packed food products and the continuing growth of convenience food and ready meals. "These factors have been at the core of the demands from retailers and customers for fresh produce to be pre-packaged for convenience," says Paul Griffin, marketing director of Ishida Europe.
This often requires tackling difficult-to-handle products in a very controlled way. Equipment has been developed that will overcome the fact that many fresh products, such as meat, poultry, and seafood, have 'stickiness' problems which can affect automated weighing systems. Although solutions are now available, and can be integrated into the line, they do not come cheap. Specifiers have some cost-effectiveness sums to resolve. And, it is not only fresh products that present difficulties -- marinated vegetables, glacé cherries and even pasta can present 'stickiness' problems.
PROBLEM SOlVING
Caution needs to be exercised when integrating and installing new equipment. For although the integration of weighing equipment and other systems into one line can, and should, result in improvements it is often the case that, as one new way of doing things is introduced and a line problem is solved, a knock-on effect causes another problem or two.
Automation and the use of increasingly sophisticated equipment may lead to speedier and more efficient processes. However, such improvements can bring bottlenecks elsewhere. As a consequence, additional pressure is being placed on equipment manufacturers and suppliers to overcome such difficulties and meet the demands of customers who have decided to install fully-integrated processing and packaging lines.
With speed and accuracy being the key drivers for most new equipment purchases, integrated systems, properly installed, can bring enormous benefits. At St Merryn Meats in Cornwall, for example, the key to the success of a recently-installed line has been the integration of a checkweigher and a metal detector system.
Richard Clatworthy, technical manager, explains that the Loma Systems-supplied equipment "provides a check on thermoform packs of mince at a rate on our automated packaging line that is 60% faster than the system it replaced"
"The new installation also has resulted in less downtime and given us a real push forward in terms of processability and reliability," he says.
Flexibility is a key consideration in meeting the current trend for smaller production runs, and changeovers need to be as quick as possible. Griffin says: "Competition among retailers has meant that all packs -- even the humble tray -- now come in a wide range of shapes and sizes to help create differentiation on the shelf. So a variety of weighing requirements and packaging designs must be catered for."
Factory space is another critical consideration and machines with ever-smaller footprints are being introduced. This is where the integration of individual machines has provided advantages. The weigh-price-labeller, which integrates pack weighing and labelling operations, is a good example of what can be achieved. As a result, multi-head weighers can form part of a complete factory management system and interface with other sections in the process and packing lines.
Other key considerations are that installation, commissioning, and maintenance are made easy.
Ishida is one company offering complete line solutions. As a single supplier of all of the components, the company believes that such an approach not only improves reliability and performance of the line but will also significantly lower the life-time cost of ownership.
With 85% of his company's equipment sales going into the food industry, Easiweigh's md Neil Andrews is well placed to confirm that there are many more specifiers seeking to amalgamate weighing and other functions on to the packaging line.
"As a manufacturer of automatic weighing equipment handling virtually any free-flowing products we have the responsibility to advise and ensure that integration on the line is successful," he says. "Many food production companies still weigh by hand, and for them to jump from this method to multiple weighing systems is a big decision."
Easiweigh's products are set somewhere between the manual and the automated equipment fitted into a line. "Our linear weighers are, perhaps, a little less sophisticated than the all-singing, all-dancing units that are on the market, but they are more flexible, more portable, and generally take up less space. I believe that many of our customers will benefit from the fact that set-up and changeover periods can be handled more quickly with Easiweigh's equipment," says Andrews. "Similar time-savings can be made thanks to the reduction in strip-down problems when switching units from one product to another."
The units can be incorporated with other equipment -- labelling, pricing and packing -- into a line as and when production developments require. In fact, among the advantages being promoted for Easiweigh's most recent equipment offerings are that they are designed for semi-automatic or fully-automatic operation with other systems.
"These new weighers are completely mobile so can be used within packaging lines or mounted over packaging systems," says Andrews.
SHIFT IN DEMAND
The increased demand for fixed-weight packaging has also influenced the trend towards integration of production line activities. For example, weigh-price labelling in lines with a mix of vacuum- and flow-wrapping.
Dave Evans, sales director of Delford Sortaweigh, highlights the point that the requirements of many of his customers have shifted over the past few years. Currently, sales of weighing systems by Delford are split about 40% (variable weight) and 60% (fixed weight). Five years ago the figures were the other way round.
"We supply to the Kerrygold plant in Leek, Staffordshire, where 60,000t of hard cheese are handled each year and processed into over one million packs. Many leading retailers have specified fixed-weight cheese packs over the past five years because of its marketing, pricing, and stockholding advantages," says Evans.
"But there is still a demand for variable weight packaging," he adds. "Although sophisticated, computer-controlled cheese cutters now are employed, cheese is a natural product that can change in shape and size during the manufacturing process. As a result, a fixed-weight operation will involve some give-away leading to increased costs for retailers."
Kerrygold operates fixed-weight and variable-weight lines. In the early 1970s, when the company first specified weigh-price labelling systems from Delford, operation was at 70 packs a minute. Now, the latest machines, from the same source can handle packs at speeds of up to 160 packs/min. Used on flow wrapping and vacuum packing lines they operate at speeds of up to 150 packs/min (200g portions) or 125 packs/min (500g portions).
"However, it is not only about speed", says Kerrygold's production director Carl Ravenhall. "We are under pressure to get things right-first-time so developments that improve the flow and pack presentation are important. In addition, reliability is vital as we must keep downtime and maintenance work to a minimum, however complex the mechanical and software engineering becomes."
For the future, Kerrygold is working with Delford to develop new equipment covering the weighing of product prior to wrapping.FM
key contacts
- Delford Sortaweigh01255 241000
- Easiweigh01905 28075
- Ishida Europe0121 607 7700
- Loma Systems01252 893300