For the testing of rings, two electronic systems were supplied to an internationally operating machine manufacturer for integration into a mechanical system including control. The inspection task involves detecting a 0.5 mm FBH at a depth of 0.5 mm in front of the rear wall.
For this purpose, the ring to be tested is positioned centrically on a turntable. Depending on the type of ring, the inspection can be carried under rotation from either the inside or the outside in an immersion tank. By setting the appropriate parameters in the control system, the rotational speed and the gradient per rotation can be adjusted according to the dimensions of the ring. The evaluation is carried out by means of KARL DEUTSCH‘s own software ECHOVIEW in the strip chart version. Here, the back wall is monitored during the entire test cycle by means of a preset monitor gate. During the test, results are visualised via a live strip chart. In the event of a flaw, the lifting/rotation stops and the operator is given the opportunity to take a closer look at the suspected defect or to continue the inspection. Since the manual alignment of the probe is generally very time-consuming, KARL DEUTSCH took this test task as challenge to automate the alignment of the probe to the test specimen by means of a collaborative robot. The probe is attached to the robot arm as a so-called tool and the focus point of the probe is defined as a reference point (Tool Center Point – TCP). In ECHOVIEW, an algorithm was implemented as a link between the robot and the evaluation, which takes over the control of the robot and thus provides the basis for automation. Starting from a initial position, the vertical alignment of the probe is carried out by rotating it with respect to the x- or y-axis of the workpiece surface. To do this, the amplitude is recorded for a large angular panning of one axis (approx. ±7°) and the best orientation is determined using curve fitting. The procedure is then repeated for the other axis based on the determined orientation. To further increase the accuracy, the procedure is repeated in a second step with a smaller angular range.