Top test rig for the technologies of the future

Fuel cells are considered to be one of the most important efficiency technologies of the future: In the cells, hydrogen reacts with oxygen to produce water, electricity and heat. The cells almost always operate without pollutants, as the only waste product is water vapor. That is why this technology has the potential to change our mobility and many other industries for the long term.

The key components of any fuel cell are bipolar plates, which are layered into so-called stacks. Their core task: to physically and electrically connect the anode of one cell with the cathode of the neighboring cell. To make this possible, flow profiles are milled into the plates on both sides, through which hydrogen flows on one side and air is supplied on the other. Bipolar plates can be made of graphite, graphite-polymer compound, metal, or ceramic.

An eye on the micrometer 

The Austrian company YOUR-TOOL specializes in precisely these high-precision components as well as other future technologies. At the Freundorf / Lower Austria site, high-precision embossing tools for the production of bipolar plates have been manufactured for the international market since 2019. "We mill the finest surfaces < Ra 0.12 on the tools, which have a contour accuracy of < 7 thousandths of a millimeter," explains Andreas Zöttl, CEO of the company and a trained toolmaker. The tolerances of the high-precision embossing tools are < 5 μm for flatness and parallelism. "Our smallest tool diameter measures just 0.1 mm," says the CEO. "So we pretty much know what 1 µm is and can render it precisely."

In 2006, the company had started manufacturing foil stamping dies with CFRP stamping frames and has since specialized in high-precision tools that only a few suppliers worldwide sell; tolerances are less than 3 µm. In addition to bipolar plates, the company manufactures punching tools for battery technology as well as micro components made of steel, ceramic carbide and bright and polished milled parts and more. In addition, YOUR-TOOL is also active for the optical industry.

Three high-end measuring devices from Mahr in use

Since the micrometer matters in production at Freundorf, YOUR-TOOL requires high-precision metrology. No less than three high-end measuring devices – the MarSurf PS 10, the MarSurf XCR 20 and the MarSurf CM mobile – come from Mahr.

The tactile and mobile MarSurf PS 10 is used directly on the milling machine at YOUR-TOOL. Here, it supports quality assurance specialist Aaron Karger in precisely checking the surface quality < Ra 0.2 of the milled parts. "Due to its small size, the PS 10 is ideal for location-independent measurements – vertically, horizontally and even overhead if necessary – the display can be digitally rotated," explains Nevzat Maksuti, sales engineer at Mahr Austria. Thanks to its removable feed unit, the mobile tool can be used flexibly in production and manufacturing. The device is equipped with a very intuitive operation that makes it as easy to handle as a smartphone or tablet. The automatic cutoff selection always ensures the correct measurement results. "On request, ready-to-use PDF protocols can be created directly in the measuring device, as well as data backup as TXT, X3P, CSV and PDF files. Another advantage is that customer-specific comments can be entered for the PDF log directly on the MarSurf PS 10," continues Maksuti. You can see an application example in the video.

Roughness and contour evaluation with just one measurement

With the MarSurf XCR 20, however, quality manager Karger checks the straightness of the punching tools or compares the contour accuracy with the CAD data in the laboratory. In this way, he can reliably track down any deviations. The combination measuring station from Mahr enables both roughness and contour measurements to be carried out at the same location. "We benefit greatly here from the measurement and evaluation software, which we use to control and position the feed unit and the measuring stand. The various interactive controls support the evaluations and automatic processes," says Zöttl. Measuring the upper and lower contours is possible with the so-called "double-tip probe," whereby these contours can additionally be evaluated in relation to each other. "Comparing nominal and actual profiles is child's play, and we can even select different tolerances within a profile by designation," explains Karger. "Import and export of dxf files for target/actual comparison is also supported."

Mobile 3D surface measurement

To check the surface quality of the milled tool in the nanometer range, YOUR-TOOL also has a MarSurf CM mobile in the measuring room. The optical measuring system is based on robust confocal technology. The typical measurement time for a single field of 800 x 800 µm is five to ten seconds. The measurements are fast, contactless and independent of the material. With its motorized axes, the MarSurf CM mobile offers the possibility of stitching larger measuring fields at a consistently high resolution. With an objective nosepiece, a color camera and a variety of software solutions, the measuring system easily meets the requirements of measuring tasks on bipolar plates. "With the CM mobile, DIN EN ISO-compliant roughness measurements, analyses of 3D structures and the measurement of geometries can be carried out. The evaluation of structuring and volume parameters is performed automatically," explains sales engineer Maksuti. The measurement results are transferred to a freely definable measurement protocol.

Investing in the right environment

"These measuring devices are excellent and ideally suited for our measuring tasks," emphasizes CEO Andreas Zöttl, "but they also need the right environment, otherwise we cannot measure in fine dimensions. That was the reason why we invested in a completely new production facility about three years ago, which is fully insulated and air-conditioned. This allows us to guarantee a temperature tolerance of + 0.2°C in our measuring room, ensuring maximum precision in manufacturing and quality assurance." The huge demand proves the Austrian entrepreneur right to focus on the highest manufacturing quality: The tools for the production of the bipolar plates Made in Austria are ordered from all over the world.

Do you have any questions, suggestions or are you also interested in MarSurf metrology? Then please feel free to contact us at info@mahr.com.