Quality Inspection at Production Speed

Inform-QC can, for example, be integrated into an unused station of a progressive die, eliminating the need for an additional external inspection station. The technology is based on photometric stereo: the component is illuminated and captured from different directions. From these images, the system calculates a digital representation of the surface topography and compares it with a reference. This makes it possible to detect subtle deviations and assign them to potential process stages or tool components.

The analysis is carried out continuously at production speeds of up to 400 strokes per minute without slowing down the production cycle. The underlying approach can also be applied to other stamping, deep-drawing and forming processes.

“At high production speeds, downstream quality control may come too late. Our goal is therefore to detect changes where they occur – directly within the forming process. The component surface not only provides information about the quality of the individual part, but can also indicate the condition of the tool,” says Hasan Kutlu, researcher at Fraunhofer IGD.

Changes to the surface can, for example, indicate abrasion or material deposits on the tool due to adhesion. Detecting such changes at an early stage enables companies to respond more quickly and reduce scrap. At the same time, the data collected provides a basis for condition-based maintenance and, in the future, predictive maintenance.

Further Development for Lubricated Surfaces

Previous research focused on dry metal surfaces. In industrial forming processes, however, metal strips are usually lubricated. The lubricant film changes the optical properties of the surface and therefore creates additional challenges for camera-based analysis.

In a recently launched follow-up project, Fraunhofer IGD is therefore investigating how the method can also be applied to lubricated surfaces. The researchers are examining how the influence of the lubricant film can be taken into account or deliberately utilized during digitization and quality analysis. The aim is to bring the technology even closer to the conditions found in industrial forming processes.

Experience Inline Inspection at EuroBLECH

Fraunhofer IGD will present Inform-QC at EuroBLECH in Hanover. A specially developed demonstrator recreates a continuous manufacturing process on a compact scale: different formed components are fed to the sensor system one after another and digitally captured. Visitors can see firsthand how quality inspection can be integrated into an ongoing production process.