Drying Time and Moisture Removal as Function of Temperature in Polyamide-Based Composite Filament

This study investigates the drying behavior of three polyamide-based 3D printing filaments (PA6-GF, PA6-CF, and PPA-CF) under varying temperature conditions. A comparative approach was applied using both segment-based and spool-based drying experiments. Moisture loss was recorded at 70 °C, 95 °C, and 120 °C, and the drying kinetics were modeled using a four-parameter logistic (4PL) function. Results revealed temperature-dependent differences in the drying rates and equilibrium moisture levels, with PPA-CF exhibiting the highest thermal resistance. The segment-based measurements enabled a precise kinetic evaluation, while the spool-based tests provided insights into real-world drying performance using hobbyist equipment. This study highlights that, while all three filaments benefit from pre-drying, optimal conditions vary significantly depending on the polymer matrix and reinforcement. The proposed 4PL-based modeling approach proved effective for characterizing the moisture removal process and can support improved drying protocols prior to fused filament fabrication. These findings contribute to a better understanding and optimization of filament conditioning practices in additive manufacturing.