Profitable lines

As any estate agent will tell you, property values are determined by 'location, location, location'. If your house is deemed to be in the right place, it will sell at a premium.

But on the food factory floor 'orientation, orientation, orientation' holds sway. Get your biscuits, your chocolates or your pouches of juice pointing in the right direction at the right time on your processing and packaging lines and make automation work for you - and you can avoid spending a fortune on all-singing, all-dancing robots.

Line things up properly on the conveyor and they'll be OK. Fail to do so and you'll have problems - as the Natural Fruit and Beverage Company found a year ago when planning to double its output of hot-filled flexible pouches of soft drinks, fruit juices and smoothies.

It was filling about 80 pouches a minute, but business for the Coatbridge, Glasgow-based contract manufacturer and distributor of juices and drinks was going through the roof. It wanted to increase output to 160 pouches a minute to satisfy customers such as Del Monte and Pepsi.

It knew its hot fill line, two steam tunnel sterilising lines and cold water cooling bath could cope. What worried the company was what would happen at the end of the conveyor line - at the packing station.

Packing was already labour intensive and the company didn't want to double the number of employees operating the process. "Throwing more people at it didn't make a lot of sense," says md Iain Martin. "And not being a large company (£2M turnover this year) we didn't have a huge budget of millions of euros for robotic automation, which was one suggestion."

Advice service

So Martin turned to the Food Processing Faraday Partnership (FPFP), the technology knowledge advice service run by PERA, formerly the Production Engineering Research Association, in Melton Mowbray. "It was very difficult for us to pin down someone who could help us. But they had helped us in the past with advice on a particular problem," he said. FPFP called in Adrian Marshall, director of Crafty Tech, the Aylesbury-based conveyor consultancy and self-styled "ingenious machine developers", who spent hours in Coatbridge looking at the Natural Fruit and Beverage Company's operations.

The result? £20 spent here on welding two small bars to the filling line. And £20 spent there on fitting some plastic guide blades into the cold water bath. The bars keep the pouches that come from the filling line pointing the same way as they drop on to conveyors that take them into the steam tunnels. And the plastic blades keep the hot pouches exiting the steam tunnels correctly oriented as they travel through the cooling bath on to the final packing conveyor line.

Oh yes, and £10,000 was spent on a new circular packing table to eliminate product back up that was a problem on the original, straight packing line.

Orientation, orientation, orientation. By maintaining control of the orientation of its products through the production process, the Natural Fruit and Beverage Company has doubled output to around 10M pouches this year. But it employs the same number of people, making for a potential annual saving of £50,000 in labour costs. And all for well under £11,000.

"That was the key," says Martin, "maintaining some control over the orientation of the pouches. With hindsight those little bars on the drop into the steam tunnels were blindingly obvious. But it needed a third person to point it out. It cost buttons but it made a big difference to maintaining control of the product."

Marshall, at Crafty Tech, agrees. "Many issues with automation start with the poor transfer of items from one conveyor to the next. If things aren't properly aligned or the speeds aren't set to optimum, you are building in nasties that sting you later on. And the final automation has to be that much cleverer to cope with the badly positioned products."

Interfaces between conveyors are very important, but they are not understood and nobody takes responsibility for the transfer of products between conveyors, he argues.

Not rocket science

"So it's never as good as it could be. A lot of things I get involved with start with people saying: 'We get terrible alignment at the end of our process. We can't pack things. Help!' And I'll go and look at the process and there will be all sorts of alignment issues that are not rocket science to cure but that need a bit of clever thought and understanding."

Marshall is now trying to formalise his experience and understanding of what can go wrong with conveyors. Crafty Tech has begun a research programme to investigate product disturbances caused by transfers from one conveyor to the next over a whole range of operating conditions and geometries.

"We're using experimentation and statistical techniques to identify, quantify and summarise the effects of key factors affecting transfer precision," says Marshall. "The plan is that the resultant understanding will remove much of the black art of conveyors and identify key factors that exacerbate alignment issues. By configuring transfers to avoid these, product disruption in processes can be minimised."

Initial experiments in which the relative speed of the two belts was varied have confirmed what he already knew by the seat of his pants - that you get minimal product disturbance if the belt speeds are the same. And the larger the speed differential between belts the larger the disturbances.

"The next phase of experimentation will be to map the effect of other relevant factors such as belt surfaces, end-roller size, gap between belts, belt alignment and product size shape and weight and attempt to predict the effect of combinations of these factors, to identify ways of achieving high-speed differentials with minimal disruption."

Marshall hopes his work will show him a number of "new tricks" to prevent disruption and to improve orientation during transfers, thus adding to Crafty Tech's portfolio of patented product-handling techniques.

Marshall says he has searched high and wide for theoretical data on this. But he hasn't found any. He believes this is because there's no way of mathematically modelling what happens when products transfer between conveyors.

"The maths gets blurred because it's all to do with friction. What I am doing is not a mathematical approach but an empirical approach. I am running hundreds of tests and then statistically looking at the results rather than doing the mathematical modelling that the academic approach would take."

But the food industry's first mathematical approach to modelling what happens on conveyors may be about to get off the ground. At Bristol University, Dr Graham Purnell, research fellow in the Food Refrigeration and Process Engineering Research Centre (FRPERC) is preparing a bid for a government research grant. He wants to describe, mathematically, the shape of food products and the disorder states these will lead to when the products are moved around.

This should, suggests Purnell, help automation suppliers design better equipment.

"If, in any situation, you can mathematically describe the level of disorder and the amount of structure you want, you can design a generic system for going from higgledy-piggledy to something structured that works well with automation," he adds.

A couple of food manufacturers and automation suppliers are interested in Purnell's proposed three-year project.

And he hopes to be able to put in an application for an Engineering and Physical Sciences Research Council grant within the next few weeks.

"We're not sure what will drop out of the research, but if you have a system to describe order and structure, you can do something about how well you preserve it." FM

KEY CONTACTS​* Crafty Tech 01844 296161​* FRPERC 0117 928 9319​* Natural Fruit and Beverage Company 01236 429042​