Filament drying

Prusa's published table gives concrete values: PLA at 45 °C for 6 hours, PETG at 55 °C for 6 hours, TPU at 60 °C for 4 to 6 hours, ASA at 80 °C for 4 hours, PC Blend at 85 °C for 5 hours and carbon-filled PA11 at 90 °C for 6 hours. The rule behind them is simple: stay below the material's glass transition temperature and allow enough time for vapour to leave the inside of the spool. A microwave will not do, and a kitchen oven without fine temperature control can melt the spool. After drying, the filament must go into an airtight box with desiccant or it will reabsorb moisture within hours.