Belgian food robotic scale-up Alberts builds blend station with low-maintenance, lubrication-free igus linear guides

Fancy a refreshing smoothie? Then head for Antwerp’s Decathlon. That’s where a blend station made by Alberts, a Belgian food robotic scale-up, has recently been installed. It features a fail-safe robot that works very hygienically, quietly and quickly thanks to igus linear guides. Customers have a fruity refreshment in their hands in just 90 seconds.

June 2023 in Antwerp. The first hot days of the year are here, and the faces of customers entering the Decathlon sports shop show it. A refreshing fizzy drink before shopping? Decathlon thinks it can offer something healthier. Therefore, it recently installed a blend station made by Alberts, a Belgian food robotic scale-up. Behind a large pane of glass, visitors see ten oblong, transparent containers with frozen natural delicacies – including passion fruit, mango and banana, but also oat pellets from Alpro, a Belgian food brand, part of Danone. Guests can combine the ingredients as they please using a touch display or smartphone app. Nutritional value and calorie information are provided, and after just a few clicks, the machine starts to work.

Your dream smoothie in just 90 seconds

A robot arm grabs a paper cup and moves from container to container on a horizontal drylin W linear guide. At each stop, the frozen ingredients fall into a cup that crushes the ingredients. After dosing, the robot arm moves to the right edge of the machine, pivots 90 degrees to the left and transfers the cup to a second gripper. This moves upwards on a vertically mounted drylin SLW-1660 linear module into a blender that transforms the frozen fruit into a smoothie at up to 25,000 revolutions per minute as warm water is added. Cool – five degrees Celsius. After just 90 seconds, the drink is ready for retrieval from a dispensing compartment. The result is a quick, uncomplicated refreshment without additives that is becoming increasingly popular. There are now Alberts stations in offices, hospitals and other high traffic locations, such as the central train station in Antwerp. The same machine can also offer soups depending on the ingredients inside. “You won’t find this combination anywhere else in the world,” says Cilia Van Vaerenbergh, Innovation Project Manager at Alberts.

The long way from development to the first smoothie

In a sports shop, office or hospital, the smoothie station has to work reliably and require as little work as possible from owners. There are high demands for all machine components. This includes the linear guides, on which the robot arms and mixer move. “We were looking for guides that are compact, quiet, low-maintenance, temperature-resistant, hygienic and easy to clean. We needed a true all-rounder,” says Van Vaerenbergh. They finally found one at igus in Cologne. The robot arm moves horizontally on a drylin-W-series WS-10-80 linear rail made of anodised, corrosion-resistant aluminium. It has a flat design and torsion-resistant double-shaft geometry. The robot arm moves along it, mounted on a drylin W linear carriage driven by a toothed belt. The igus chainflex-series CF99 control cable, designed for particularly tight bend radii with limited space, follows the movement in an energy chain made of high-performance plastic. In its in-house test laboratory, igus showed that its solution was durable and therefore suitable for the smoothie station. During the test, a carriage moved back and forth on a 1,000mm linear rail in 24-hour operation – with a load of 250N. The system achieved a running performance of 2,500km, the distance between Munich and Cairo.

Particularly hygienic: igus linear guides work without lubricants

Another advantage is that, unlike metal ball bearings, the system requires no external lubrication. Microscopic solid lubricants are integrated into the plastic linear plain bearings, over which the carriage moves on the rail. They are released over time, ensuring hygienic, low-friction dry operation. “In rolling systems, there is often the risk of dirt combining with lubricating oil and forming a mixture that impairs smooth running and increases contamination risk,” says Michael Hornung, Product Manager drylin Linear and Drive Technology at igus. There is no such danger with drylin linear guides and linear axes. “Furthermore, the system can be cleaned in just a few simple steps because the liners simply push dirt and grime off the rail.” The plastic bearings can also be changed in just a few simple steps. Says Van Vaerenbergh, “These advantages help us a lot as it aligns perfectly with our goal of minimizing the cleaning and maintenance efforts for the owners. By incorporating automatic cleaning cycles, the entire system now demands no more than 10 minutes a day and this includes both cleaning and refilling.”

dryspin lead screws allow for long-lasting, low-vibration operation

Ultimately, the engineers chose a ZLW-1040 toothed belt axis for vertical cup positioning in the second part of the smoothie machine. For vertical mixer adjustment, they opted for a dryspin-series SLW-1660 linear module with a high helix lead screw instead of a toothed belt. This drive’s special feature is that, without further ado, igus has eliminated a classic in mechanical engineering: the conventional trapezoidal thread. Here, the edges of the lead screw and lead screw nut form an isosceles trapezoid. They are symmetrical – almost identical in shape and size. And it is precisely this symmetry that has now been removed. igus has increased the high-performance plastic nut’s thread edges by a factor of 1.3. The same is true of spindle thread width. This small intervention has major consequences: the enlargement means more high-performance plastic – more material that is tribologically optimised (that is, optimised for friction and wear). This leads to an increase in service life of around 30% compared to that of symmetrical trapezoidal threads. Furthermore, the engineers achieve above-average efficiency (82%) by flattening the flank angles of the lead screw and lead screw nut. “Last but not least, the system is vibration-free thanks to the rounded tooth flanks. This reduces the risk of screws and other components near the thread coming loose,” says Hornung. “The system also operates almost silently, so it doesn’t bother those working near the smoothie station.”

Equal footing

Alberts appreciates not only the components from Cologne, but also the cooperation between the two companies. “The igus experts are experienced enough to meet our designers on an equal footing,” says Van Vaerenbergh. One of the project’s challenges was the ambient temperatures. During operation at a constant -20° Celsius, condensation can form on the linear guide when the vending machine doors are opened, causing it to ice up when the doors close again, impairing carriage movement. Thus, igus recommended a drylin W linear carriage with pretension. Springs ensure that the carriage’s linear plain bearings always adjust to the current rail diameter. “For such questions, our experts put their heads together again and again to implement a hygienic, fail-safe, low-maintenance system. Productive collaboration!”