With or without milk?
October 2009
Piping hot coffee at the push of a button. The modern packing systems made by Paal are needed so that consumers can enjoy coffee with the convenience of pre-packed pods. And that company banks on the versatile, high-performance VarioFlow conveyor system built by Rexroth.
Nowadays, Grandma’s wooden coffee grinder will be found only as decoration in the kitchen. Only the rare purist still grinds coffee fresh while most consumers prefer convenient, user-friendly products – pod-type machines, for instance. These tiny pads or pillows, filled with coffee, are clean and easy to handle and make for quick and effortless enjoyment. Producing them, however, is not quite so simple. The situation is even more complicated since coffee roasters today offer many different varieties and combinations – adding powdered milk, for instance.
Solving complex tasks quickly and simply
“Our equipment has to solve the complex tasks associated with packaging coffee pods and do that in minimum space,” notes Bernhard Vaihinger. He is innovations manager at Paal, a German manufacturer of packaging machines located in the Swabian town of Remshalden.
That’s why Vaihinger banks on the VarioFlow chain-type conveyor system, since it can adapt flexibly to any requirement, even where complicated routes have to be covered. When Paal plans and sets up the consolidation and packing of pods in a complex line, then the VarioFlow module, with its wide range of standardized curves, lends design latitude. Pre-assembled groups simplify installation and subsequent changes can be effected quickly and easily with standard components. This is an advantage in regard to the total cost of ownership, too.
Synchronize, consolidate, pack
“One particular challenge is synchronizing bags with differing contents. This is the case, for instance, when a certain number of coffee pods is to be merged with an identical number of milk pods. All that has to be synchronized with upline production.” That’s how Vaihinger describes one of the central requirements put forth by the coffee roasting companies. In one of its most recent projects, Paal appended a carton packing machine directly to a milk pod production line. Several hundred milk pods arrive on parallel conveyor systems. The bags containing the coffee pods are fed from an autonomous production line by way of so-called separator systems.
Finally the retail sales packages exit the carton packing machine in cycles of just seconds and at differing batch sizes. “The varying conveyor lengths alone, with their many curves, make synchronizing the bags, lying on friction chains, very difficult,” Vaihinger comments. The company DFS Montageautomation, a Rexroth system integrator for VarioFlow, employs shrewd solutions to master these difficulties. Working on behalf of Paal, it makes up the interfaces to the production line.
Coffee added to milk, not vice versa
Milk will normally be added to coffee when making up a cappuccino but in this system the coffee is to join the milk. The divergent speeds represent a major challenge. Coffee sachets – the bags sealed at the edges and containing the pods themselves – arrive from the bag separator at a different rate than the milk sachets. It is necessary to adjust these two conveyor systems so that the coffee matches the frequency for the milk sachets.
“To do this, the bag separators and their conveyors run at modified velocities – that’s part of the Paal know-how”, Vaihinger reveals. The system will sort out bags that overlap or vary in dimension. They are routed via return conveyors to re-join the production cycle. The conveyor speeds are matched to each other so that the number of coffee sachets matches exactly the number of milk sachets arriving at the merging station. The bags, once sorted, are placed on shuttles or carriers. They move the bags to the carton packing machine, a standard Paal device. Paal also employs VarioFlow chain-type conveyor systems to set up the recirculation for these shuttles and to move the filled cartons to the crate packing unit.
With the exception of special tipping and transfer belts for the interfaces and the lateral guides built to Paal specifications, DFS thus assembles the complete conveyor system using parts taken from the VarioFlow “construction kit”.
More information:
www.boschrexroth.com/packaging
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