CrackInspect

Project context

Cracks can occur during the manufacture of components, e.g. during forging, casting or forming. Such cracks should be detected as early as possible in the value chain in order to save costs and resources. At the same time, not all cracks are relevant to the load. Specific sorting therefore further reduces waste.

Project description

Fraunhofer IPM developed test balls that can check components for surface and geometry defects from all sides simultaneously every second. Components can be photographed from all sides as they fall freely through the test ball. Using different light wavelengths, a large number of images are taken and analysed for crack detection.

In addition, software was developed to analyse and evaluate the images obtained. This converts the images into models and performs stress and fracture mechanics analyses to determine for which applications the damaged components can still be used.

Project results

In the project, surface inspection was expanded to include testing for microscopic cracks. The camera images are compared with the target CAD, analysed for cracks and evaluated on a location-specific basis. This allows all typical inspection tasks to be automated in the production cycle. A flux agent is used for crack testing, which glows under UV radiation and thus makes the cracks visible. In the project, the technology was tested with metal parts up to 20 cm in size. However, the functionality is also suitable for crack detection in other materials.

Further development of the IWM VERB software has made it possible to perform an automated acceptability assessment of surface cracks. This requires knowledge of the mechanical stresses in the component to be assessed, which are determined in advance using finite element analysis with a CAD component model. The subsequent fracture mechanical evaluation is carried out either with the aid of an interface or by the finite element solver accessing the calculation modules of IWM VERB. The results of the calculations can be output as the permissible or critical crack length at various positions in the component or as corresponding remaining service lives.

Further utilisation of the project results

By testing the components using the developed software and hardware, defective components can be detected at an early stage and sorted out according to their load characteristics. In addition, attention can be paid to ensuring a long service life as early as the product development stage.

The project results will be used and further developed in follow-up projects. Contracts have already been signed with almost 20 companies for this purpose, and further contracts are in the pipeline. Public project applications for further development have also already been approved (ORKa3D, WESCAPRO) or submitted for approval (FlexProKom).

The project resulted in the above-mentioned patent and several software licences. A technology readiness level (TRL) of 7 was achieved.