High temperatures, noise and the smell of oil go with industrial manufacturing like yin goes with yang. But in toolcraft's glass production hall, this is no longer the case. Upon presenting their employee IDs at the entrance and stepping into the facility, workers are met with the sound of — nothing. Through small windows on each of the twelve 3D printers, however, one can observe laser beams fusing layer after layer of metal powder in a dazzling dance of light.
Whenever new technologies dominate markets, they bring many question marks with them. One of these question marks is quality assurance. Jens Heyder points to a monitor showing two images captured with the ZEISS Axio Imager light microscope and enlarged to 50 times normal size. The image on the left shows a cut from a good component. The image on the right, however, contains cavities and weld defects.
"Under high levels of stress, this could result in cracks," warns Heyder, who has been working as a materials technician in toolcraft's materials lab for three years. The materials lab, however, is just one component of toolcraft's end-to-end quality assurance process. Inspections are performed after each process step. And the machines used for this all bear the blue ZEISS logo: a ZEISS Axio Imager and a ZEISS Axio Zoom.V16 microscope; a ZEISS ACCURA, a ZEISS CONTURA and a ZEISS DuraMax coordinate measuring machine; and an optical 3D scanner.
"ZEISS is the only company that provides metrological technology for the entire additive manufacturing process chain with complete and consistent data," explains Christoph Hauck, one of the company's three managing directors.
The 42-year-old first came into contact with additive manufacturing at toolcraft in 2005. In those days, the technology was "still very much in need of improvement" and was suitable only for use in prototypes. Today things have changed. toolcraft's components meet the strict requirements of the aerospace and medical technology industries, and they perform and hold up just as well as traditionally manufactured parts.
The manufacture and application of these components is also more efficient, as demonstrated by a 3D-printed stator guide vane which guides the flow of gas through a stationary gas turbine. The curved shape of the blades are optimized using complex simulations and are barely manufacturable with reasonable amounts of traditional machining.
To scan complex blade geometries such as these, "we used the Blade software module from ZEISS," says Markus Miehling, head of quality assurance. With the 3D scanner Miehling is able to get a quick overview of the blade package.
Quality assurance in additive manufacturing is largely uncharted territory. As such, toolcraft's materials experts have created their own method for determining the grain size distribution and structure of metal powder. The powder is mixed with an epoxy resin, and the hardened samples are then partially ground and put under a ZEISS Axio Zoom.V16 microscope for inspection.
3D-printed parts also require special treatment when it comes to tactile measurements. Since the parts are too raw to be scanned when they come out of the printer, the probe is used to measure individual points instead of tactile scanning the entire component surface.
If the part is fine, it is sent to the machining specialists so that threads can be drilled in, radii can be optimized and the surfaces can be "finished" using traditional machining methods. Now, when the component is measured again on the ZEISS ACCURA, a scanning tactile probe can be used. This coordinate measuring machine is outfitted with ZEISS' mass technology (multi application sensor system), which enables the operator to quickly switch between different sensors, including an optical single-line sensor.
toolcraft already uses many devices in the ZEISS 3D ManuFACT portfolio, but their arsenal does not yet include a scanning electron microscope or a computed tomography scanner. They do not know what devices they will purchase in the future, says Christoph Hauch, but they are sure they will be from ZEISS. "Quality assurance is a major challenge in additive manufacturing, and it's good to know that we have an experienced partner like ZEISS on our side."