Professional coffee machines thanks to precision ballscrews

For many of us, it is not only the aroma and taste of coffee or an espresso that we love, but also the very act of making it every day. When asked about personal rituals that give us a sense of calm and structure in our daily lives, morning coffee is the most frequently mentioned answer. Almost nowhere else in Europe is as much coffee consumed per capita as in this country.

The best thing to hear in the morning – coffee's ready!

Who can resist the spicy aroma of a freshly brewed espresso? For many coffee lovers, the black pick-me-up simply flows out of the coffee machine at the touch of a button. Yet inside a fully automatic coffee machine is a wealth of exciting technology. Mechanical machine components such as ballscrews from Eichenberger play an essential role in this.


Reliable mechanics guarantee coffee enjoyment

The Eichenberger passion for perfect motion constantly leads the company in new directions. Products from the thread specialist in Burg (CH) comparable to those of similar dimensions or quality perform better than customers expect. Using individual designs or special manufacturing processes, the thread professional adapts ball and sliding thread drives to suit the application and makes the impossible possible. This is how we create drive solutions that bring our partners' innovations to the forefront of the market. One such interesting product is the customised ballscrew for professional coffee machines used in the catering and hotel industries.

It's the pressure that counts

Coffee lovers have high expectations of their brew. So how exactly is the perfect cup made with your favourite beans? Excellent coffee is the result of a complicated interplay between the brewing temperature, brewing time and pressure. These variables must be finely coordinated. Hot water is forced through a tightly pressed bed of finely ground coffee beans under pressure. The right pressure is crucial for the perfect espresso.

At the request of a leading coffee machine manufacturer, Eichenberger developed a customised ballscrew drive to power the press to compact the ground coffee. This precise drive system effectively optimises the taste experience. No easy task: the coffee grounds, known as the puck, must be pressed with a uniform force of more than 1200 newtons that is always identical - only then will the fourth espresso taste just as good as the first one.


Ballscrews create the perfect coffee aroma

People commonly believe that the inner workings of everyday appliances are the preserve of electronics. Given the elegant design of these fully automatic coffee machines, the fact that the crucial functions are mechanical goes unnoticed. Yet on the inside, two cold-rolled screw drives from Eichenberger Gewinde AG do the precision work necessary to extract the full aroma of the coffee.

The heart of every coffee machine is the piston unit with the "plunger". Two robust, side-mounted ballscrews guide the punch to press the coffee grounds. Maximum pressure builds up if the outlet is completely blocked. However, this is not the goal at all, as the water is intended to run through the coffee. A good espresso needs an extraction pressure of at least 9 bar, but if the brewing pressure rises too quickly, the coffee often tastes bitter.


Immer gleich guter Kaffee dank präziser Kugelgewindetriebe

The Swiss screw drives meet all the specifications to ensure that this professional coffee machine produces creamy cappuccino or spicy espresso. The ballscrews deliver uniform and constant force over the entire surface of the coffee puck.

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  • Pressing: when the grinder has ground the fresh beans, the powder enters the brewing chamber. This is where the plunger presses the fine coffee grounds together. It is essential that this is done extremely evenly, as if the "puck" is not uniform thickness the water will flow through unevenly. The resulting aroma would be bitter.
  • Guiding: two screw drives are used to prevent any jamming. They guarantee precise, parallel force.
  • Ejection: the final step ejects the used coffee grounds.

Expertise under the microscope
What makes the Carry ballscrew the right functional element for this application?

Two 14 x 4 mm ballscrews are used in this fully automatic coffee machine. These filigree, quiet and yet resilient ballscrews are characterised by their high level efficiency. They make it possible to generate the necessary force for the pressing process despite the limited drive power available.

Cold thread rolling produces very precise shapes with high surface quality. The longitudinal fibres of the material are not cut in the thread rolling process, unlike in grinding, milling or turning, but are deflected. This results in a compressed, smoothly rolled, extremely resilient surface, essential for a long service life of the spindle. The Rz of approximately 1.0 on the flanks of the thread brings great advantage. The rolling friction coefficient for steel balls is approx. 0.0013 compared to 0.1 to 0.05 for steel-on-steel (lubricated) sliding friction. The excellent sliding properties of the cold-rolled ballscrew ensure minimal abrasion and minimize surface contamination. As a result, the balls can roll smoothly and very quietly.

 

Carry Hurter 16x5 FGI-1 Ballscrew drive for fully automatic espresso and cappuccino coffee machine

 

READ MORE ABOUT TAILOR-MADE SCREW DRIVES

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