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Reducing giveaway and improving efficiency

10 May 2021

Advances in multihead weighing technology has equated to reductions in giveaway and increases in efficiency levels. Neil Wightley explains. 

It is easy to take the multihead weigher for granted. It has become a stalwart on the food production line, delivering high speeds and accuracy to help meet production targets and keep both customers and end-consumers happy.

Ishida’s first multihead weigher – launched in Europe in the 1980s – was considered a game changer for the food industry – reducing product giveaway on products such as snacks and confectionery. The continuous improvements that have been made to multihead weighers over the years mean they are still having a big impact on many companies’ bottom lines.

This is important because product giveaway remains a major concern for many food manufacturers. A recent Ishida customer survey found that over 50% of  respondents cited this as still being their biggest weighing challenge. 

It is therefore important to emphasise that while the principle of multihead weighing has remained the same over the past 50 years, what the weighers can deliver has come on in leaps and bounds. The many incremental improvements and enhancements that have been introduced during this time continue to deliver some impressive savings.

Reduced giveaway
Taking one example from Ishida’s own installation base, a snacks manufacturer was already achieving high throughput, producing 100 x 20g packs per minute over a 16-hour daily shift. A new system was proposed that could deliver an increased line speed of around 4%, a further reduction in giveaway of 0.2g per pack, a 0.3% reduction in rejected packs and about two hours additional machine uptime each month. At first glance these might appear to be minor improvements – but together they represented a projected annual added value for the manufacturer of 180,000 euros.

The experiences of a confectionery customer were just as impressive. The replacement of the company’s existing Ishida weigher with a new model further reduced product giveaway by 0.5g and increased overall speed by 10 packs per minute. These relatively small improvements equated to an annual saving of 450,000 euros and led to payback on the machine being achieved within six months.

Such examples back up the results of a poll conducted during a recent Ishida webinar on weighing, where 45% of respondents confirmed that they viewed the reduction of product giveaway as representing the best chance to create extra value within the business.

And maximising this value creation has been another important part of the ongoing development of multihead weighing technology. Over the years numerous models have been developed for specific applications, very often for products that previously had been considered too difficult to handle in an automated weighing system – everything from fresh meat to dried fruit to salad leaves.

Design enhancements
Accompanying this have been many design enhancements, focused on improving product feed and control, and simplifying and speeding up routine operations such as changeovers and cleaning.

This close alignment between weigher and product brings several benefits – a reduction in operating costs and increased production efficiency, and better utilisation of the machine to drive improved quality and reduced risks.

Equally important, these enhancements have been supported by software developments. Particularly significant is how the software has evolved from merely controlling the weighing process, to also including data capture, monitoring and reporting. This is especially vital as processing and packing lines have become increasingly integrated, with equipment linked together to provide a faster and more efficient operation.

As the saying goes ‘knowledge is power’. Being able to easily access a line’s current state and quickly analyse the data provided creates the increased visibility that enables lines to be kept running at maximum performance and efficiency, since small issues that might be slowing down the line can be identified early and dealt with immediately.

Similarly, these advances in software have also allowed weighers to self-optimise. For example, product flow can be regulated to ensure a consistent amount to all hoppers. Head optimisation is used to ensure that product does not stay in a hopper for too long, an important benefit for chilled and frozen items.

Alongside this, the operation of the weigher has been made even more user-friendly for line personnel. In particular, information screens have become more intuitive, further speeding up machine set up or problem solving. A multihead weigher will continue to operate quite happily with one weighing head out of action, but the loss of this head halves the number of weight combinations available for each weighing cycle, which quickly adds up to a big drop in overall efficiency. Such a problem can now be instantly flagged up for operators to take remedial action.

This combination of relevant data and advanced software can have a marked effect on efficiency levels. Whereas earlier multihead weigher models offered rates of around 95%, these can now be increased to closer to 99% on current weighers. Even more important, such a rate is being achieved far more consistently.

All technologies evolve over time. The first mobile phones were a revelation in their day, and while many will continue to work perfectly well, they lack the majority of the features of the latest smartphones. Unlike the evolution of the mobile phone, multihead weighers may not have changed that much in terms of looks, but certainly the technology that drives them has continued to advance. Today’s models have kept pace with the markets they serve, helping to cope with increased competition, meet and anticipate new trends, and respond to ever-changing consumer demands and retailer requirements.

Neil Wightley is multihead weigher business manager at Ishida Europe.

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