The 450-strong Exterior Plastics team at BMW Leipzig has become the first in the BMW Group network to deploy terahertz paint thickness measurement on plastic exterior components, replacing the manual scalpel-and-microscope inspections previously used on injection-moulded bumpers, side sills and spoilers. The contact-free scanner comes from Spanish technology partner das-Nano.

The system, branded Irys, is described by BMW as the first deployment of terahertz inspection on plastic components anywhere in the network. It mounts on two robots inside the plant's existing end-of-line measurement cell, sitting at the end of the painting process. The scanner reads multi-layer paint by analysing reflected terahertz waves, completing each measurement in seconds with micrometre-level accuracy. The result lands in a digital record rather than on a technician's bench.

Painted bumpers, side sills and spoilers carry a tighter film-build tolerance than steel body panels. Small deviations that pass on metal read as a visible defect on plastic. That is why the Leipzig line ran a dedicated manual inspection at the end of the paint process in the first place.

How big is the operation that switched over?

The Leipzig Exterior Plastics team feeds both Leipzig assembly and BMW's Dingolfing and Regensburg plants in Germany. Christoph Theiselmann, Head of Exterior Plastics Production at Plant Leipzig, framed the change in quality-control terms:

"Terahertz measurement technology replaces complex manual inspection with a fully automated solution. The combination of higher measurement accuracy, direct process integration and full digitalisation delivers tangible benefits across the entire production chain."

What does this change for the production team?

For shop-floor inspectors, the swap removes the destructive cut-and-measure routine on painted plastic parts, which used to scrap the sample it verified. Process engineers gain a per-component digital data set, the prerequisite BMW cites for AI-based early-deviation detection and closed-loop process optimisation planned next. The system already handles all component carrier skids; all colour variants are being qualified in sequence on the new line.

What does this change for the buyer of Leipzig's parts? Nothing visible at the finished-vehicle level yet, since the check happens before the bumper, side sill or spoiler reaches the bodyshell. But Dingolfing and Regensburg now receive parts with a digital quality record attached. That format feeds straight into their own assembly KPIs, easier to integrate than the paper-based handovers the old manual line produced.

What to watch next

BMW has flagged the new data feed as the foundation for AI-based process control across the paint stack. Paint shops at Dingolfing and Regensburg — current Leipzig component customers — will track whether the same inspection architecture migrates into their own plastic-parts cells or stays centralised at Leipzig. Throughput is set by the two-robot cell configuration in the existing end-of-line booth, making cell duplication the natural next scaling step if volumes rise. The first AI-driven deviation-detection use cases on the line are the next concrete milestone to track.