In the south of Germany, a freshly baked pretzel with butter and aromatic coffee is a must on any breakfast table. The perfect shape, ‘symmetrically twisted, with a fat belly and thin arms’, requires a lot of manual work – or clever automation technology with Festo components. The Schill bakery in Denkendorf has opted for the latter - with the aim of using its specialised staff for other tasks – for example for adding the final touches to bakery products.
Before the pretzel enters the oven, it passes along a short production line. The dough is first kneaded and portioned automatically. Then it is transported on a conveyor belt to the next work step: rolling out. Here, the dough strand is formed into the typical pretzel shape: a fat ‘belly’ that thins out into the ‘arms’ at either end.
This dough strand is now aligned on the conveyor belt with a positioning unit from Festo, so that the grippers can later grip in exactly the right places and form a symmetrical pretzel. This is followed by the actual twisting process, in which gripping technology with actuators from Festo is used. Thanks to the sensitive end-of-arm tooling, the dough strand is gently picked up at the ends. Then it all happens very fast: in less than a second, the strand of dough becomes a precisely twisted pretzel.
Suitable for use in dusty environments
Anyone working in a bakery should not be allergic to flour – the same applies to the components of a pretzel-twisting machine. Master baker and owner Martin Schill appreciates that Festo pneumatic components still function perfectly even with high levels of flour dust. This requires special seals, for example.
After a short setting-up time the twisting machine can do more than just pretzels
The twisting machine is a real jack-of-all-trades: whilst one moment it is producing pretzels non-stop, after a short setting-up time it can already braid complexly twisted single-strand braids. For this purpose, new gripper units are mounted which are adapted to the end product.
If an error should occur during retooling, this is no problem thanks to sensor technology: the machine detects the incoming dough and stops automatically if, for example, pretzel dough runs over the belt in single-strand mode.
The machine produces around 2,300 pretzels per hour – almost four times as fast as Martin Schill twisting pretzel dough for an hour non-stop. ‘The advantage is that the employee can use the time gained to use their expertise for other tasks in the bakery – we have lots of delicate and individual tasks for which we can use any free pair of hands,’ says Martin Schill.