Automatic dispensing system with Drylin linear technology

Every Sunner needs a cold beer - so it's off to the beer trolley. But there's a queue that forces you to wait. An annoyance that One Two Beer from Vienna would like to spare concert-goers. That's why the company has developed an automatic beer dispenser. Employees place two plastic cups next to each other - similar to a coffee machine. One push of a button later, two tapping heads move to the bottom of the cups. The beer flows. The highlight: tapping from below prevents foaming. The beer is tapped in just five seconds. Beer sellers are happy to have machine support in times of labor shortages.

Freedom from lubrication was required

As simple and elegant as the beer robot may seem, its construction was a design challenge. "To enable tapping in a matter of seconds, for example, it was essential to have a fast and low-friction linear guide," says Tamás Kozma, Chief Information Officer at One Two Beer. The system had to function with an accuracy of a tenth of a millimeter. It should be as compact as possible to enable fast transportation. And at the same time be resistant to the harsh festival environment - including dust, high temperatures and condensation. "As our machine works in the food sector, a 100 percent lubrication-free application with FDA conformity was also crucial for us."

Linear guide with spindle, nut and stepper motor

After a long search, the company's engineers finally found a system that met these requirements at Igus: a complete linear guide unit consisting of a compact threaded spindle and threaded nut from the Dryspin series as well as a suitable stepper motor.

Hygienic and trouble-free dry running

And this is how the linear guide from the Rhineland works: The tap is mounted on a Dryspin JFRM series flanged threaded nut. When the NEMA 23 spindle stepper motor turns the spindle, the tap moves up or down. Basically a simple system. But with a few special features: The threaded nut is made of an FDA-compliant high-performance plastic. A self-lubricating material that enables low-friction dry running. The advantage is obvious: unlike lubricated metal versions, the polymer nut does not run the risk of becoming a dirt magnet due to grease. It is easy to clean, whether with water or high pressure. The linear guide is hygienic and mechanically trouble-free. The combination of plastic and stainless steel also prevents corrosion. Thanks to the elimination of relubrication work, maintenance work is completely eliminated.

Threaded spindle achieves efficiency of 82 percent

However, it is not only corrosion resistance and insensitivity to dirt that lead to a long service life for the linear guide. Just as important: Igus has increased the thread edges of the nut by a factor of 1.3 with the Dryspin technology. The same applies to the width of the thread of the spindle. This enlargement of the thread edges means that more high-performance plastic is involved in the force transmission. And therefore more material, which is optimized in terms of friction and wear. "Thanks to this asymmetry, we have managed to extend the service life by around 30 percent compared to symmetrical trapezoidal threads," says Torben Hendricks, Head of the Dryspin screw drive business unit at Igus. In addition, the flank angles of the threaded nut and spindle are flattened. "This enables us to achieve an above-average efficiency of 82 percent."