Suitability of infrared thermography for monitoring the hot extrusion of insulating materials

This work presents first results of research aiming at the inline measurement of thermal conductivity of insulation materials produced by hot extrusion. Samples of insulation material were heated by laser pulses or cooled by cooling fingers. The resulting hot or cold spots were tracked, and their infrared intensities were recorded. These are a measure of the complex time dependency of the temperature in the excited areas. After an initial phase presumably characterized by the sample's semitransparency, the intensities follow a well-understood proportionality to t-0.5 at least for some time, which allows the extraction of the thermal conductivity by fitting.