Festival season is in full swing. To keep the queues at the beer to reasonable lengths, One Two Beer GmbH has developed an automatic beer tap. Its core is a mobile tap head that moves to the bottom of the cup, which it fills in five seconds without foam-over – built with a lubrication-free, hygienic, durable lead screw from the igus dryspin series.
The goal of One Two Beer GmbH from Vienna is to spare concert-goers or any person going to a crowded event with annoying long queues before having a drink. Therefore, it has developed an automatic beer tap. Two plastic cups are placed side by side – much like a coffee machine. At the touch of a button, dispensing heads move to the bottom of each cup. The beer flows. Tapping from the bottom eliminates foam-over. The beer is tapped in just five seconds, so concert-goers don’t have to wait long. Beer vendors enjoy machine support in times of labour shortages.
No lubrication
As simple and ergonomic as the beer robot may appear, building it was a technical challenge. “For tapping in a matter of seconds, one necessary item was a fast linear guide with as little friction as possible,” says Tamás Kozma, Chief Information Officer at One Two Beer GmbH. The system needed to work to within a tenth of a millimetre. It needed to be as compact as possible to allow quick transport. And it had to be insensitive to the harsh festival environment, which includes dust, high temperatures and condensation. “Since our machine works in the food sector, a 100% lubrication-free application with FDA conformity was also crucial for us.” After a long search, the company’s engineers finally came across igus, where they found a system that meets these requirements: a complete linear guide unit consisting of a compact dryspin-series lead screw and lead screw nut and a suitable stepper motor.
High-performance plastic and stainless steel allow hygienic, trouble-free dry operation
This is how the linear guide works: the tap is mounted on a flange lead screw nut from the dryspin JFRM series. When the NEMA 23 lead screw stepper motor rotates the lead screw, the tap moves up or down. The system looks simple, however there are some special features: the lead screw nut is made of FDA-compliant high-performance plastic, a self-lubricating material that allows for low-friction dry operation. The advantage is obvious: unlike lubricated versions made of metal, the polymer nut will not become a dirt magnet due to lubricating grease. It is easy to clean with water or high pressure. The linear guide is hygienic, and its mechanical system works flawlessly. The pairing of plastic and stainless steel also prevents corrosion. As there is no need for relubrication, there is also no necessity for any maintenance.
Lead screw efficiency of 82%
However, resistance to corrosion and dirt are not all that result in a long linear guide service life. igus has also enlarged the nut’s thread edges by a factor of 1.3 for dryspin technology. The lead screw’s thread pitch is also broader. Enlarged thread flanks mean more high-performance plastic for power transmission and thus more material that is tribologically optimised (that is, optimised for friction and wear). “This asymmetry has enabled us to extend service life to about 30% longer than that of symmetrical trapezoidal threads”, says Hendricks, Head of dryspin Lead Screw Drive Business Unit at igus. The igus team have also flattened the flank angles of the lead screw nut and lead screw. “This gives us an efficiency of 82%, which is above average.”
