The PrintDry filament dryer is an in-line filament dryer, which is designed to dry and to feed the filament into a 3D printer at the same time. The migration of moisture into the filament occurs over time and will eventually slow and stop when the moisture content reaches a state of equilibrium with that of the surrounding air. At the equilibrium point, the moisture content will be evenly distributed throughout the entire filament’s interior. The water molecules inside it are attached to the polymer molecule chains, forming a strong inter-molecular bond. This bond is what makes drying the filament difficult. The PrintDry filament dryer is designed based on the following principles: drying temperature, moisture concentration differential, drying time and air flow. The filament is heated up in a PrintDry unit forcing the molecules inside the filament to move more vigorously, this weakens and breaks the bond between the moisture and polymer allowing water molecules travel freely through the filament towards its surface.