Developing Premium Headlights Faster and Having Stable Production Processes

Bernhard Voglauer holds up a light module that is used in many headlights and explains how it’s been assembled. In the front of the module is the lens with a microstructure on its surface; this distributes the light to achieve homogeneous bright/dark transitions. Behind that are the lens holders and a light source with 84 light diodes. These are controlled individually by a circuit board and lead the clearly-defined light through the silicon lightguide to the lens. This is how targeted fade-out scenarios can be achieved. A metal cooling element and a fan regulate the temperature. “An important point is this: We have to inspect our components after they’ve been assembled because otherwise certain error sources cannot even be identified,” explains Voglauer. “Our coordinate measurement machines and optical scanners can’t do that, of course.” During the validation process, ZKW pays special attention to how the light optics have been installed in order to avoid potential damage later on. For example, it once happened that some thermal stress, caused by the ligh-diodes, led to some abrasion on the lens holder and lens. “We would have never been able to identify that if we had only inspected the individual components in a disassembled condition,” stresses Voglauer. But such insights are critically important as they enable ZKW Lighting Systems to ensure stable production processes and deliver the premium quality their customers expect.

The measurement lab at ZKW Lighting Systems therefore uses the industrial computer tomograph ZEISS METROTOM 1500, alongside various coordinate measurement machines and an automated optical measurement system. A ZEISS METROTOM 800 is also on the shop floor. ZKW has relied on X-ray technology for a long time to inspect and measure assembled modules or entire headlights, but this was always done by an external inspection laboratory. “But we had a lead time of around three to four weeks,” explains Bernhard Voglauer. “This is of course was much too long and didn’t fit our idea of efficiency. With our own devices, the final results are available much, much faster, which saves us valuable time in development and allows us to react much faster. That in turn
lowers our costs in production.” A high performance of 500 watts and a high resolution thanks to the 3K detec- tor (in the case of the ZEISS METROTOM
1500) guarantee fast results and a clear view. Even when faced with a complex design with different types of materials, such as copper, aluminum, or different types of plastic with different thicknesses, the computer tomographs can handle it all. “We can do everything very well thanks on the one hand to the different filters and light settings. And on the other hand, a lot can still be done in post-processing too, ” explains Martin Janisch, team leader in the measurement laboratory of ZKW Lighting Systems. “Whether correcting artefacts or correcting scattered rays, the software offers numerous possibilities to prepare the result in an optimal way.” The high performance of the CT systems also enables ZKW Lighting Systems to scan more than 20 parts at once, in addition to scanning entire headlights — an important advantage.

In addition to the powerful hardware, the software was another important criterion in deciding for the ZEISS METROTOM. The analysis of the results is done in ZEISS INSPECT X-Ray. The employees of ZKW Lighting Systems were already using the ZEISS ATOS ScanBox, an optical measurement device. ZEISS PiWeb is used for recording all results. “This seamless interplay between the hardware and software was a huge factor for us because ZEISS software is very user-friendly and it offers a visually clear interface with functionalities that are intuitive and easy to find,” stresses Martin Janisch. “For us that means a substantially lower training effort. It’s always been easy to use and we never have any problems.” Bernhard Voglauer confirms that: “This focus on good, intuitive usability and the fact that the hardware and software work together so well were the key factors in our deciding for ZEISS.” In the software itself, ZKW Lighting Systems takes advantage of the possibility to do visual volume inspection in order to mainly inspect the assembly of the components. 3D volume and 2D cross-sections show whether the silicon lightguide is in the right place.

The measurement-technical inspection of the components, including the verification of form and position, are also done completely in ZEISS INSPECT X-Ray. Fly-through videos of the interior of the component and PDF measurement reports are regularly shared with the colleagues from tool development so they can jointly determine the required optimizations. All inspection results from the measurement laboratory are fed into ZEISS PiWeb and then integrated into all systems. Reliability in delivery, the service, and the strong operation of the systems were also important factors for ZKW Lighting Systems: “We have had so many good ex- periences with ZEISS in the past – they’re a competent partner that offers great service. You can always rely on them to fulfill every promise they make,” says Bernhard Voglauer. ZEISS therefore remains a firm partner for ZKW Lighting Systems when the task at hand is to illuminate the way into the future – with high definition and glare-free.