Additive manufacturing, or: what geeks and beer cans have in common

Geek density is relatively high among my friends. How is this manifested? For example: I just want to “briefly” check the messages on my mobile, and what do I find? In response to the discussion about re-opening Bavarian schools, my friends have already been happily busy calculating how large a classroom would have to be if it is to accommodate 20 pupils, each seated two metres apart from the next. In this process, dot-shaped children in a vacuum and hexagonal grids, for example, are used to arrive at optimum space utilisation. Got it? The best response, by the way, came from my colleague Kai: one square metre is sufficient if you were to stack first-formers on top of each other at a distance of two metres each. Artificial intelligence or geekery? The boundaries are fluid.

Another thing that regularly makes geek hearts beat faster as far as I can see is additive manufacturing, or – as the process is referred to in everyday conversation – 3D printing. That is hardly surprising as it serves to translate into hands-on reality many of the creative ideas incessantly emerging from a geek’s brain. Detail-obsessed board-game figures or self-developed components for a mountain bike – the possibilities are immense.

Because this also and especially applies to industrial applications, Krones operates its own Technology Centre in Neutraubling for additive manufacturing. Thekla Herrmann from Central Research and Development is confident: “Additive manufacturing of parts and components offers a whole lot of opportunities and options in mechanical engineering because with 3D printing even the smallest of numbers, e.g. a prototype, can be cost-efficiently produced.”

The reason: for classical production processes, you need tools or moulds that have to be matched specifically to the parts being manufactured. In 3D printing, by contrast, a 3D model created in CAD is converted into two-dimensional layers which are then applied one after the other during printing. The only tool needed here is a printer. And this printer serves to make a wide choice of different objects.

This is why 3D printing is particularly suitable for making one-off parts or ultra-small series, for example, when prototypes or spare parts for relatively old machines are needed. And it is also comparatively simple with this process to manufacture components featuring complex geometries. One example in this context can currently be viewed on Krones’ virtual booth for interpack 2020: a can twister produced by a 3D printer.

“Can twister”? That sounds like just another of those typical geek products. But don’t be fooled: a can twister has quite a real job to do, in a brewery, for instance, where it vertically inverts beer cans after these have been filled and seamed by 180 degrees, so that these can then be pasteurised standing upside down.

There were quite a few obstacles to overcome in the Technology Centre in order to produce the new can twister, as Andreas Neuber, a technology expert for additive manufacturing, explains: “The development team had to analyse a multiplicity of points, like the kinematics involved, meaning the optimal motion sequence of the cans as they are inverted. Then there were also the tribological characteristics, meaning the friction behaviour between the cans and the material.”

The development team needed several attempts in order to meet and master these challenges. But this, too, is one of the advantages offered by additive manufacturing: the path from design to actual implementation is short. This means the development people can promptly see what modifications are still needed where, and respond directly.

And the 3D-printed can twister offers a significantly shorter procurement time than its conventionally produced counterparts. What’s more, the complex geometry of conventional can twisters renders manual machining inevitable, which in its turn may result in shaping deviations. With 3D printing, the ideal can guide configuration can be reproduced as often as you like and can in addition be quickly and easily adapted to handle new container formats. Highly promising prospects for the can twister. How it is coping with hands-on reality is now revealed at one of Krones’ customers where it’s running under shopfloor conditions as Thekla Herrmann explains: “The can twister is now being subjected to rigorous trialling in a field test. In the next few months, we shall see how it performs there.”