BMW’s Leipzig plant has started using terahertz measurement technology to check paint thickness on plastic exterior parts, replacing a slower manual process that damaged the parts being inspected.
The system is used in series production for components such as bumpers, side sills and spoilers.
BMW said it can measure paint layers without touching or cutting into the part, with inspections carried out directly within the production line.
It said the system has been scaled up for automated, precise and repeatable checks. The plant is the first BMW site to integrate the technology into in-house production for exterior plastics.
The technology is built around Irys, a terahertz measurement system developed by das-Nano for industrial inline inspection. Sensors mounted on two robots are positioned near the plastic part, then use reflected terahertz waves to calculate the thickness of individual paint layers.
BMW said the readings take only seconds and reach micrometre-level accuracy.
Previously, paint thickness checks at Leipzig relied on scalpels and microscopy.
That meant some parts were destroyed during inspection, while paint deviations could also be detected later than ideal. The new setup gives BMW earlier warning of process drift, reduces waste and produces digital measurement data that can be used for process control.
The Leipzig plastics operation has about 450 employees and supplies injection-moulded exterior parts not only to Leipzig, but also to BMW plants in Dingolfing and Regensburg.
BMW said the system is being enabled for all colour variants and could later be rolled out to other plants, painted body shops and suppliers
















