Optical Measuring Speckle Systems for NDT

In view of the fact that quality control is becoming more and more important and that the time for developing new mechanical parts decreases, optical nondestructive testing methods are very useful in industry. Especially, speckle interferometry. This paper describes three different interferometric nondestructive testing systems. A 3D-Holography-System, a Shearography-System and an Interferoscope are presented in order to enable a qualitative and quantitative evaluation. These three systems are used to examine a STAB-O-FOCS (an automatic Flap Opening and Closing System). The exterior of the strained housing is examined by holographic and shearographic means. Usually when measuring internal deformations the chassis has to be opened. With an interferoscope it is possible to examine inner structures through a small hole. Often such holes are available, for example an sensor which is inserted into the chassis of the STAB-O-FOCS. If you dismount the sensor you can examine the inside through this hole with the interferoscope as described in this paper. The interferoscope is a combination of an endoscope and a shearographic interferometer (a modified Michelson-Interferometer as a shearing device) for analyzing out-of-plane deformations. It is a newly designed measuring system that examines deformations and strains on surfaces of inner structures which are difficult to reach. This paper provides the principles behind the systems described above and shows the results of the STAB-O-FOCS examination. The evaluation is performed by the newly developed software “OPTIS”. It was developed especially for interferometric methods such as the Holography, the Shearography and the Interferoscope.