ANALYSIS OF MATERIAL FLOW PATHS IN INJECTION COMPRESSION PULTRUSION - DEVELOPMENT OF AN EXPERIMENTAL ANALYSIS METHODOLOGY

Abstract

The presented study introduces and validates an experimental methodology for quantifying resin residence time in injection compression pultrusion processes. When designing an injection box for a new pultrusion profile, one common challenge is achieving homogeneous and rapid impregnation of the dry fibre. It is also necessary to avoid premature gelation inside the injection box due to high residence times. Resin residence time is used as a metric to evaluate the efficiency of the injection box. The presented method measuring the residence time involves pultruding a coloured resin until steady-state operation is reached, after which an abrupt matrix colour change is used to visualise the established flow field, by using a second stream of coloured resin. Cross-sectional samples are prepared under constant conditions and analysed by digital image correlation. Sequential images are processed using pixel-based classification and converted into numerical datasets, enabling a time-resolved assessment of the colour transition. This enables the determination of the point in time of specific regions fully exchanged with the new resin, while also capturing the onset, location and duration of backflow phenomena. This approach provides a quantitative basis for characterising and optimising the performance of the injection box in pultrusion.

Authors 4

1. Felix Flammer Aachen

   RWTH Aachen University

   Affiliation as printed

   Aachen University

2. Jonathan Paul Alms Aachen

   RWTH Aachen University

   Affiliation as printed

   Aachen University

3. Kai Fischer Aachen

   RWTH Aachen University

   Affiliation as printed

   Aachen University

4. Christian Hopmann Aachen

   RWTH Aachen University

   Affiliation as printed

   Aachen University