Most of us not only love the smell and taste of coffee or espresso, but also the daily ritual. Morning coffee is the most frequently mentioned answer to the question about personal rituals that give us peace and structure in everyday life. Hardly anywhere else in Europe is more coffee consumed per capita than in this country.
The best three words in the morning: Coffee is ready!
Who doesn't love the aromatic scent of freshly brewed espresso? For most coffee connoisseurs, the black pick-me-up simply flows out of the coffee machine at the touch of a button. Yet the inside of a fully automatic coffee machine is packed with exciting technology. Mechanical machine elements play an important role here, such as ball screw drives from Eichenberger.
Reliable mechanics ensure coffee enjoyment
Eichenberger's passion for perfect movement is constantly leading the company in new directions. The thread specialist from Burg (CH) delivers more than customers expect from products that are comparable in terms of dimensions or quality. Through individual design or special manufacturing processes, the thread professional adapts its ball and sliding screw drives to the application and makes the impossible possible. This results in screw drive solutions that bring the partners' innovations to the forefront of the market. One interesting product is the customized ball screw drive for professional coffee machines in the catering and hotel industry.
It all depends on the pressure
Connoisseurs have high expectations of their coffee. But how do you make the perfect cup with your favorite beans? Excellent coffee is the result of a complicated interplay between the variables of brewing temperature, brewing time and pressure. These parameters must be precisely coordinated. Hot water is forced under pressure through a firmly tamped bed of finely ground coffee beans. The right amount of pressure is crucial for the perfect espresso.
At the request of a leading coffee machine manufacturer, Eichenberger developed a customized ball screw drive that drives the plunger for compressing the coffee powder. This precise drive system effectively optimizes the taste experience. No easy task: the coffee cake, also known as the puck, must be pressed evenly with a force of more than 1200 newtons and always be identical - only then will the fourth espresso taste just as good as the first.
Ball screws complete the coffee aroma
It is commonly believed that the inner workings of everyday appliances are the domain of electronics. The fact that the key functions are mechanical is not apparent from the elegant design of the fully automatic coffee machines. Inside, however, two cold-rolled screw drives from Eichenberger Gewinde AG perform the precision work required to bring out the full aroma of the coffee.
The heart of every coffee machine is the piston unit with the "plunger". Two laterally arranged, robust ball screw drives guide the plunger to press the coffee powder. The maximum pressure builds up when the way out is completely blocked. However, this is not the aim, as the water should run through the coffee powder. A good espresso requires an extraction pressure of at least 9 bar. If the brewing pressure rises too quickly, the coffee often tastes bitter.
Always the same good coffee thanks to precise ball screws
The Swiss screw drives meet all the requirements to help this professional coffee machine produce creamy cappuccino or spicy espresso. The ball screws ensure an even and constant application of force over the entire surface of the coffee puck.
- Pressing: Once the grinder has ground the fresh beans, the powder enters the brewing chamber. The plunger now presses the fine coffee powder together. This must be done extremely evenly. If the "puck" is not equally thick everywhere, the water will flow through unevenly. The result would be a bitter aroma.
- GuidanceTwo screw drives are used to prevent tilting. They guarantee an exact, parallel force.
- Eject: In the last step, the "used" coffee grounds are ejected.
Competence put under the microscope
What makes the Carry ball screw drive the right functional element for this application?
Two 14 x 4 mm ball screw drives are used in this fully automatic coffee machine. These delicate, quiet and yet resilient screw drives are characterized by their high efficiency. They make it possible to generate the force required for the pressing process despite the limited drive power available.
Thread rolling using the cold rolling process produces very precise geometries with a high surface quality. In contrast to grinding, milling or turning, thread rolling does not cut the longitudinal fibers of the material, but deflects them. This results in a compressed, smoothly rolled, extremely resilient surface, which is essential for a long service life of the spindle. The roughness values of around Rz 1.0 on the thread flanks provide a major advantage. The rolling friction coefficient for steel balls is approx. 0.0013 compared to sliding friction steel on steel (lubricated) 0.1 to 0.05. The excellent sliding properties of the cold-rolled ball screw ensure minimal abrasion and offer little surface area for contamination. This enables the balls to roll quietly.
