Measure without pausing

"If someone speaks in the room, the sound of speech alone would disturb the measurement process and make the results unusable." Hüseyin Serbes uses these words to describe the extreme sensitivity of so-called white light interferometers. The engineer is fascinated by this high-precision technology. He and his colleagues will soon be founding a start-up to develop it further. The measuring instruments are able to scan the surface properties of objects down to the nanometer range. They play a decisive role in the quality inspection of machine-produced components, for example in the semiconductor industry, aerospace technology or medical technology. Here, the micro- or nanostructuring of the surface determines its properties, for example how water-repellent, paintable or antibacterial it is. Highly sensitive measuring devices can often only test these structures under strictly controlled conditions, on an anti-vibration table in an isolated environment, as the jargon goes. This slows down production considerably and incurs high costs.

The idea: Measurements directly during production
But what if you could check the workpieces during production? Professor Peter Lehmann was already thinking about this question before his appointment to the University of Kassel. He and his team at the Department of Metrology have been researching a technical solution for over ten years. The breakthrough finally came. His research assistant Serbes explains enthusiastically: "Our new measuring device is now completely insensitive to vibrations." The engineer specializes in optical systems and optical design. The team has integrated a technical trick that makes this device revolutionary: so-called passive disturbance vibration compensation.

The innovation: passive interference vibration compensation
The heart of the new instrument is an additional interferometric distance sensor that measures the distance between the instrument and the object with high precision at short intervals. In parallel, the white light interferometer scans the surface of the workpiece in the same beam path and with a high degree of synchronization. Special electronics record the signals and transfer them to specially developed software. A sophisticated correction algorithm filters out all environmental influences from the data. This eliminates all interfering vibrations and creates an exact image of the surface. "It no longer matters whether a milling machine, the workbench or the measuring device itself is vibrating. Not only speech sound, but even a blow with a hammer on the measuring table can be completely corrected and does not affect the measurement result," says Serbes.

The support: funding from EXIST research transfer
This technological breakthrough was also recognized outside the university: together with electrical engineers Alexander Metzker and André Stelter, Serbes received EXIST research transfer funding of 1.33 million euros from the Federal Ministry for Economic Affairs and Climate Protection in 2024. This supports university members in founding innovative, technology-oriented companies with unique selling points and high economic potential. With the support of the University of Kassel, the team is now working on founding its start-up "WaveVision". The university is providing them with 85 square meters of laboratory space. Professor Lehmann is also continuing to support the project to turn this scientific innovation into a company as a mentor with his specialist expertise.

The future looks promising: A pilot customer is already planning to use the measuring device from "WaveVision" to scan workpieces during the machining process. The company, which develops systems for ion beam processing in a vacuum, can thus shorten a calibration process that currently takes several days to a few hours and directly detect and correct errors in production. The pilot customer is impressed by the new measuring instrument. "And so are we," adds Serbes.