Aim: To boost capacity on Muntons’ 25kg sack packing lines
What: Brillopak robotic palletising cell incorporating a Nachi PLP 130 robot, plus infeed and outfeed conveyors
When: Summer 2012
Muntons has been producing malt and malted ingredients for more than 80 years. During this time the company has grown to become a significant player in the supply of malts, malt extracts, homebrew kits, flours and flakes to the international food and drink industry. The company’s Stowmarket mill is operational 24 hours a day, five days a week. Prior to a new investment last summer, the mill was at maximum capacity, producing 17,000 tonnes of crushed malt and malted ingredients annually.
However, with Muntons experiencing growth in domestic and overseas demand for these ingredients, it became apparent that capacity needed to be ramped up. One of the bottlenecks identified was the palletising line, which palletises 25kg sacks of grain from two bagging lines, one manual and one automatic.
The palletising operation was already automated following investment in a layer palletiser nine years ago. The problem, though, was that it wasn’t fast enough or flexible enough to cope with higher throughput.
“We could only ever run one bagging line into it,” explains David Mercer, project engineer at Muntons. “In the past we’d been able to get round this with careful planning, but it had reached the point where we needed to increase packing volumes.”
In July 2011, Muntons asked three equipment suppliers, one of them end-of-line automation specialist Brillopak, to propose a robotic palletising line that would increase throughput by 50%.
Brillopak designed a robotic palletising cell incorporating a Nachi PLP 130 four axis robot, plus infeed and outfeed conveyors, which impressed Muntons with its attention to detail and quality of engineering.
“We could see that it was robustly designed using only top quality components and that the layout had been carefully thought out,” says Mercer. “Some systems seem, on the face of it, to be well built, but when you come to maintain them they have parts you can’t source.” The user-friendliness of the Brillopak system was another factor in its favour, according to Mercer.
“We wanted a robot that would be easy for us to programme,” he says. “For example, slightly changing the position of sacks on a pallet is often quite a difficult thing to do, whereas with the Brillopak palletiser, it is easy.” Brillopak created 65 different pallet load recipes for the robot, accommodating every conceivable combination of bag size and type.
The company also provided a solution to the problem of restricted ceiling space, mounting the robot on a plinth to increase its reach range. This allows it to work round obstacles like slipsheets and sacks despite the low ceiling.
The contract was awarded to Brillopak in December 2011, the design was agreed in February 2012 and three months later, the line was up and running.
Sacks from two separate packing lines feed the Nachi robot. Each line passes through a bag flattener, metal detector and labeller onto a pick-up conveyor. Brillopak specified a conveyor with central belt and end-stop and on which each roller was driven to ensure that sacks would be presented to the robot in the correct position.
Programmed with 65 different recipes for each line, the robot feeds two different pallet stations, each of which has its own pallet dispenser. The robot head auto adjusts for different bag sizes and loads two pallets at a time. Full pallets are moved down the line to a stretch wrapper with hooder. From there they are fed to a series of outfeed conveyors. This is an improvement on the previous line in that fork lift trucks are no longer needed to transfer pallets to the stretch wrapper.
The entire system is driven from a single colour touchscreen HMI. The robot signals are fed to the HMI meaning that there is no requirement for the operator to use the robot pendent. The system is safety zoned into two areas with safety guarding and CAT 4 light guards.
The line is capable of 600 sacks per hour, more than fulfilling Muntons’ brief.
“We wanted 50% more throughput but we got more. The previous system did 300 bags per hour; this line can do twice that,” says Mercer. “Hopefully in time we’ll fulfil that capacity.”