Part manufacturer reduces reject rate with traceability solution

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ETO Magnetic, an industrial product manufacturer based in Stockach, Germany, has reduced the pseudo-failure rate of its manufactured parts from four per cent to almost zero with a vision-based traceability solution.

The company produces several million defect-free parts for the automotive industry with just a few seconds between steps in the production process. It has installed Cognex In-Sight 5100 ID readers at its facilities in Germany, Poland, China and the United States to create a continuous monitoring system for traceability.

Laser-etched and dot peen 2D codes provide the most important methods for creating an individual fingerprint for quality assurance.

During the production process, metal components are thermally and mechanically distorted to the extent that dot peen 2D codes suffer collateral damage. When stamping the tiny 6 x 6mm identification areas in the dot peen process, tool wear can lead to differences in impression depths and angles of the individual marking points. When the last generation of code readers attempted to read these dot peen codes, up to four per cent of parts were determined to have unreadable codes.

‘This rate was clearly too high for us,’ said Process Planner Klaus Schwanz of ETO Magnetic. ‘In our manufacturing processes, a product with an unreadable code is treated as a reject. In a plant handling several million parts, our old ID readers were simply not up to scratch.’ With In-Sight 5110 fixed-mount ID readers, the 2D dot peen codes could be successfully identified with 100 per cent certainty.

For metal surfaces that were, in part, highly reflective and particularly difficult to identify, the developers at ETO Magnetic used flat white lighting. Most of the 2D codes are applied solely for internal traceability of the manufacturing processes. In this way, the company can trace every part, however small, in all individual components, down to the delivered load of copper wires for electromagnetic windings. Possible process or material faults are detected early and corrected.