Modeling Fiber Dispersion in a Single‐Screw Extruder for Long Fiber‐Reinforced Thermoplastics

ABSTRACT Understanding the mechanics of fiber attrition during the plasticizing process is important in predicting the strength of long fiber‐reinforced thermoplastics (LFT) composites. Fiber dispersion has been found to impact fiber damage during processing and therefore final fiber length in the final part. However, little work has been done to understand the mechanics of fiber dispersion and its effects on fiber length. This study investigates fiber dispersion during the extrusion process of LFT pellets. Screw pull‐out experiments were performed to determine fiber dispersion along a single‐screw extruder at various processing conditions. A dispersion model is proposed for a single‐screw extruder to predict fiber dispersion along the screw. The model incorporates hydrodynamic stresses and total deformation along the helical length of the screw geometry to predict fiber dispersion. Results showed good agreement between the model and the experimental measurements.