NON-DESTRUCTIVE INSPECTION OF PLASTIC COMPONENTS WITH TERAHERTZ TIME DOMAIN SPECTROSCOPY

摘要

The transparency of most plastics in the Terahertz (THz) range offers great potential for non- destructive testing (NDT) of plastic components. The demand for suitable NDT is rising because of the increasing substitution of metals by plastics. We present the latest results of spatially-resolved inspection of plastic components with THz time domain spectroscopy (TDS). In previous works it has already been demonstrated that THz waves are suitable for the detection of differences in wall thickness, moisture and filler content as well as for characterizing the structure of components, or to differentiate various sorts of plastics [1]. These measurements, however, were mostly made in transmission arrangement. Hence, an access from both sides of the part is necessary. In most cases of practical application, this cannot be realized. The non-destructive THz imaging of component properties in a reflection arrangement, as the next step towards practical applications, is presented in the following. For this purpose, a specific experimental setup for imaging and special data evaluation algorithms were developed. The detection of filler content and moisture fluctuations as well as the orientation of fibers are demonstrated based on examples of industrially relevant plastics.