Inspecting threads

 

To monitor the quality of components with geometries that are difficult to access – for example, boreholes with an internal thread – digital image-processing techniques are implemented. These enable defects and irregularities to be detected quickly and reliably.

The inspection concept developed by Fraunhofer IPA is based on a super wide-angle lens, which depicts the borehole from the outside. This technique is therefore much faster than with endoscopic visualization, which is the principle that most visual inspection systems are based on. The lens does not need to be inserted into the borehole and the inspection step is easily adapted to various borehole geometries with diameters of 6 mm upwards.

The images of the boreholes are analyzed using automated inspection functions. These examine the inner surface of the boring for the presence of particles and foreign bodies, verify the completeness of the thread and detect any damage or irregularities in the thread. The inspection functions are available as plug-ins for use with EMSIS or NeuroCheck.

Under certain circumstances, the structure and brightness of the inspected surface may fluctuate significantly – even if products are from the same batch. This may be due to tool wear, ageing, material differences, different coatings or soiling. Thanks to flexible software algorithms, the evaluation concept is unaffected by such surface fluctuations.