Magners cider production line

Filling time on the production line

Does your production line fill containers? Do you produce any kind of weighed product? The smallest efficiency improvements can translate into major savings, as E&T discovers.

Founded in 1988 by immigrants from the Caribbean, Wolverhampton-based piemaker Quick Food Products specialises in producing Jamaican patties with a range of meat, vegetable and fish fillings.

But, some 20 years into its business, the company felt the time was right to branch out. The likely-looking niche was producing patties for the British-based Nigerian community, as well as patties certified to carry the Halal label, indicating compliance with Muslim religious requirements.

There was, however, a problem: a lack of the capacity required to manufacture and fill the new patties. The solution came after a call to the Manufacturing Advisory Service West Midlands, which sent in food production specialists NPD Services to work alongside its own expert, manufacturing adviser Maxine Chapman.

The consultants soon established that there was too much variation in the weight of filling in the patties - and that standardising filling quantities would make significant savings. That not only took out cost, it also freed-up capacity.

'It wasn't a big technical problem, but more a question of agreeing best operating-practices, and then using them,' explains Chapman.

Quick Foods is not unique. Time and again, she says, significant improvements in the performance of filling and packing lines can be achieved by applying simple tools consistently, and through a better understanding of the parameters of the equipment that you're dealing with.

'It's not about using new and complex filling and weighing equipment, but about using what's already there properly, and about how much waste you can generate by being inconsistent,' she stresses.

Manufacturing consultants know it as 'hidden plant' - precious manufacturing capacity squandered on waste, yield loss and inefficiency.

Unlock it, and you've generated extra capacity at minimal cost. What's more, by their very nature, filling and bottling lines are 'lumpy' forms of investment. Unlike, say, a machining department, where an extra machine tool or machining centre can be bought to increase capacity in small increments, filling and bottling lines must be bought as a whole.

No wonder, then, that the hidden plant is coming under scrutiny, through offering manufacturers small incremental increases in capacity.

At C&C Group, the Clonmel, Ireland-based owners of Magners Cider, that realisation has prompted a major push towards continuous improvement activities designed to highlight opportunities to unlock the hidden plant.

'Filling-line efficiencies are very important,' says C&C's IT and continuous improvement director Shane Hughes. 'There's a lot of capital equipment on them, and the more product that you put through the lines, the greater your revenues and the lower your average costs.'

For the last 18 months, a lean manufacturing and continuous improvement programme has been under way, intent on driving down inefficiencies and boosting output levels. 'Our aim is sustainable improvements, not 'flavour of the month' quick wins that don't last,' says Hughes.

Easing the bottleneck

The scope would seem to be significant. At Lancashire-based Crown Paints, for instance, a similar lean-oriented programme, in place for roughly the same time scale, has already delivered significant savings and production improvements.

'Our factory conversion cost per litre - excluding raw materials - has fallen by 20 per cent,' reports group operations director Mike Polkinghorn, who was recruited to the role specifically to drive such improvements across the group's two factories. 'The operation wasn't lean, and had become unfocused.'

To lean aficionados, the sources of those savings won't come as much of a surprise. Under the guidance of a specially-appointed continuous improvement management team, data on key performance-metrics was gathered, flow charts were drawn to analyse added value loss, and pareto charts prepared to prioritise areas to tackle.

The key targets that emerged: over-manning, in terms of both direct and indirect labour; a failure to keep bottleneck filling machines supplied with paint; labelling machine reliability; and the time taken by plant engineers to respond to breakdowns. Over the months that followed, lean improvement teams tackled each, driving down costs while increasing productive capacity.

And there's still plenty more to go at, stresses Polkinghorn - a conclusion that doesn't surprise Wilson Dhanaraj, a specialist consultant in the consumer packaged goods manufacturing division of global technology consulting firm Wipro Technologies, and himself a former manager of two Pepsi-Cola bottling plants in Asia.

'On any line, the filler is usually the bottleneck - the operation where efficiencies are most critical,' he says. 'Although it's supported by important equipment upstream, and by packaging equipment downstream, the filler is almost always a good place to start looking for improvements.'

It's a well-worn path. 'We typically start an improvement operation by looking at the filler valves, and at their associated springs and 'O'-rings,' he observes. 'And in terms of which filler valves to focus on first, data capture - and statistical analysis of fill rates - can pinpoint target areas to focus on.'

Dhanaraj's own top tip for improving filler efficiencies? Target the cleaning-in-place regime, and the people who carry it out - who are often not trained line operatives, but contract staff or relatively unskilled personnel unaware of the implications of their actions. 'Cleaning-in-place alone often isn't sufficient to clean the valves - and of course, the valves control the fill content,' he explains.

Worse, cleaning-induced damage to filler valves and product depositors is surprisingly common, adds Dennis McCarthy, a consultant at Henley-on-Thames lean specialists DAK Consulting.

'When nozzles and filling heads are disassembled during cleaning, it can be quite easy to reassemble them incorrectly,' he says. 'And if they are taken out for in-depth cleaning, damage or incorrect reassembly is all too common. Developing standard operating procedures for cleaning processes is one solution - but designing equipment so that it can't be incorrectly assembled is a much better one.'

Yet according to some experts, one of the biggest opportunities to unlock the hidden plant still lies untapped in many filling operations.

Weights and measures - what a Giveaway

Variously known as giveaway or over-fill, it's caused not so much by the variability in filling levels itself, but by the margin of safety that management builds into filling levels in order to overcome that variation while allowing them to meet legal weights and measures stipulations on minimum fill levels.

'It's a huge opportunity - but one that many plants fail to appreciate,' says Tom Wedgwood, a director at Oxfordshire-based specialist manufacturing consultancy Newton.

On any product sold that has an 'e' after the stated weight on the container, he explains, the law dictates that the average weight over the production run must be greater than the declared weight on the container, with the average weight being determined by sampling.

Furthermore, two other legally-mandated stipulations apply: first, no more than 2.5 per cent of the sample can lie between an upper and lower control limit, known as t1 and t2; and second, no product under a lower control limit, t2, may be produced at all.

Consequently, in order to comply with these stipulations, containers on filling lines are routinely over-filled with more finished product than need be the case - with Newton's own experiences suggesting that as much as 3 per cent of a plant's output can literally be given away in this manner.

The answer? First, do everything possible to minimise fill variation. It's that variability that generates the proportion of the production run that will exceed the two control limits.

'Equipment such as multi-head weighing machines can have a lot of in-built variability: everything you can do to bring the filling process under control and minimise that variability helps enormously,' says Wedgwood.

But secondly, he adds, manufacturers should work to bring the average fill level down to the minimum possible that doesn't result in products breaching the stipulated control limits - a notion somewhat akin to Statistical Process Control.

'Because shopfloor operatives and middle management typically don't understand either the legal requirements or the statistical theories that underpin them, there's a lot that can be done by way of simple training and automated logic tables that allow production teams to reduce the average fill level of a batch without breaching either of the stipulated control limits,' says Wedgwood.

And the potential is significant. 'Typically, we expect to see a plant that is running at 3 per cent giveaway to get down to around 1 per cent - which is quite a saving,' he notes. In hidden plant terms, of course, it's also equivalent to a 2 per cent capacity increase, as well as a reduction in average unit product cost.

That said, it's not for everyone. As Martin Wing, managing partner of Maidenhead-based operational improvement consultants Kepner-Tregoe points out, if a plant has more compelling efficiency challenges, then there are clearly lower-hanging fruit. 'If you're operating at 80 per cent overall equipment effectiveness, then people should be much more focused on raising that to 90 per cent and then 95 per cent,' he notes.

But Ken Mcloughlin isn't complaining. As operations manager at Wigan-based pre-prepared salad manufacturer Hazeldene Foods, he recently worked with Newton for several months to unlock aspects of the company's own hidden plant.

'It wasn't just giveaway, although giveaway was very much part of the work that Newton did,' he explains. 'But we were certainly able to change our filling settings, and make changes that added up on an annual basis to a saving that was certainly worth having.'

Recent articles

Info Message

Our sites use cookies to support some functionality, and to collect anonymous user data.

Learn more about IET cookies and how to control them