The developed software for the visual final inspection in the serial production of airbag generators is a contract development for the company ZF-TRW. Using a special variant of a Gaussian mixture model, the software learns which variations in the appearance of a product are normal and can thus specifically detect deviations and mark them for manual reinspection.
The plant in Laage produces about 50,000 airbag gas generators in different variants every day. The original visual final inspection at the plant involved the use of simple image processing methods and manual visual inspection of components by employees. Due to the high quantities and production-related material fluctuations, the previous final inspections were risky and resulted in very high stress levels for the employees.
High inspection speed with a 100% detection rate
Since airbag gas generators are a safety-relevant component, the software must meet special criteria:
- Detection rate: 100 % (no defective component is allowed to leave the factory).
- Pseudo defect rate: < 0.1 % (every suspected defective component must go to the recheck and thus slows down production)
- High inspection speed: currently < 200 ms (Due to high volumes, evaluation must be done in real time)
- Adaptability to different generator variants (about 40 product variants are in use at the plant in Laage)
The software is in productive use at the Laage plant and is currently being rolled out to other locations (e.g. Mesa in the USA and Xian in China).