Cooperation with Fraunhofer Institute ILT et al.


In Germany, about 330,000 tons of microplastics are produced each year, which enter the environmental cycle. According to the Federal Environment Agency, up to 30 million tons of ultrafine plastic end up in wastewater every year and are flushed into the oceans via rivers. Getting these tiny particles back out of the water poses great challenges for wastewater companies – Klass-Filter GmbH has joined forces with a research group of five partners and has declared war on microplastics. The idea: A filter that uses laser-drilled holes to efficiently filter out particles as small as 10 micrometers, even in large quantities of water.

Project content

The starting point of the research work is our patented Klass cyclone filter. The filter is based on the principle of centrifugal force. The filter element is a fixed filter tube into which the contaminated liquid flows tangentially at high speed. Heavy solid particles are separated by the centrifugal force in the rotating liquid column. Only the light solids settle on the filter tube. A hydrodynamic scraper rotating around the filter element continuously cleans the filter tube by suction. It thus constantly ensures optimum filter performance and also maintains the circulation of the liquid. This technology has been used successfully in industry for 20 years.

The research project now aims to equip the filter with a special metal foil that can be drilled extremely small and precisely using innovative laser technology. The demands on the drill holes are high: with pore diameters of less than one hundredth of a millimeter, the filter throughput should be able to cope with the large volumes of water in the sewage treatment plant and function robustly. This is achieved through the highest possible porosity, i.e. the largest possible part of the filter surface should be taken up by boreholes.

Scientists at the Fraunhofer ILT in Aachen have been working on the technology for efficient drilling in various working groups for several years. The scientists have developed their own simulation software that is linked to the OptiY GmbH software. This allows the process parameters to be tested realistically on the computer before the first hole is drilled. The drilling process developed in this way is then transferred to the LaserJob GmbH laser system, which has been a production partner of Klass-Filter GmbH for many years. Quality assurance specialists want to monitor the drilling process closely from the very beginning. The measuring system for this will be developed in cooperation with LUNOVU GmbH.

Products used


Metal foil with pore diameters of less than one hundredth of a millimeter


Topic at the Aachen Water Conference on 29 and 30 October 2019 at the Eurogress Aachen