Rißprüfung zerstörungsfreie Werkstoffprüfung / Rissprüfung

Press Release 19.10.2000

Main unit of the automobile - a matter of course !!
A daydream in non-destructive material testing ?

Each car is equipped with a main unit indicating immediately any failure, anywhere in the car, in order to exchange the defect part. A lot of people certainly wonder why this does not exist for the non-destructive material testing. The question, if unknown defects can be found, too, is usually answered:

                                "this does not exist" or "not possible"

Up to now, this has only been a dream. However, eddy current opens undreamt-of chances. Eddy current itself is not yet meaningful enough, because often the test is only possible at one frequency. And this is the weak point of the testing: At the mono-frequency eddy current technique, the test instrument needs OK and NOK parts to select the right test frequency. It is absolutely necessary to provide any possible defect to the instrument enabling to choose the correct frequency that shows the biggest differences between OK and NOK parts. Even when this one frequency can be divided into many parts or reflected waves, it remains only one frequency to test the parts.

The multi-frequency testing is different. This technique is like a "main unit" indicating which part is defect and which not, independent of the kind of defect. Only OK parts are needed for calibrating the instrument, and test can start. The multi-frequency technique tests and compares all parameters of the test parts with the OK parts' parameters. This progressive test method enables a quick and safe 100 % check and thus realises a short control circuit. Although several frequencies are used, the test is very quick and takes less than 200 milliseconds.

Nowadays, in a time of more and more responsibility towards the customer, it is important to control, and if necessary to correct, the production process with modern test methods and short control circuits by an additional technical guarantee. Due to the simple handling of such an instrument, the integration into a production line is a necessity.

(Karl-Heinz Schulze)