Quality control of internal screw thread with EyeVision

For the quality control of component parts with geometry that is difficult to access such as the inspection of the quality of the inside of a drilling hole, methods of digital image processing are used. In case the drilling hole has received a screw thread, the internal screw thread inspection of the EyeVision software makes sure that the thread is not contaminated with for example, borings.

The fast and reliable inspection of EVT for flaws and irregularities is based on a super wide-angle lens, which makes it possible to reproduce the drilling hole from the outside. It is not necessary to dip inside the hole. This means an advantage for the speed of the inspection. Especially in comparison to the endoscopic reproduction, whereupon the common visual inspection systems are based on. The additional suitable illumination as well as the evaluation via the EyeVision software makes the quality control even easier.

The evaluation software EyeVision

The core of the inspection system is the camera in comination with the EyeVision image processing software. In the current case the camera is from Basler, whose images are evaluated with the EyeVision software.

The evaluation of the internal screw thread is carried out with the EyeVision software and it inspects if the inside of the drill hole is contaminated with particle or debris, it verifies if the thread is complete and detects if the thread is damages or inordinate.

The EyeVision software offers not only a continuous user interface for a big variety of different image capture and processing tasks, but also a remarkable adaptability to the respective application.

With its easy-to-handle user interface and drag-and-drop programming, the software offers the user the possibility to create and change their evaluation algorithms even without programming skills. The EyeVision software has a special command for the thread inspection, which makes the programming for the application even easier.

The suitable illumination

The illumination poses a challenge, because the standard products do not fulfill the requirements of such an application. Therefore EVT is using a special illumination from Opto Engineering, which makes it possible to illuminate the drilling hole.

The described system can capture drilling holes of a depth up to three times the diameter of the hole and can be applied for drill hole diameters of only 0,5 mm.

The system also recognizes the correctness of the thread run-in and -out as well as the completeness. Mechanical debris in the whole thread and damages of the drilling hole bottom (blind hole) are also recognized.