Materials
Hygroscopic
Also known as: higroscopico · higroscópico · hygroscopic · absorbe humedad · filamento humedo
Short definition
A hygroscopic material is one that absorbs moisture from the air; in a filament, that water turns to steam inside the nozzle and ruins the print.
Full definition
When melted, water trapped in the filament boils and exits the nozzle as bubbles, producing audible pops, rough surfaces, stringing, gaps and a serious drop in layer strength. The worst offenders are polyamide, PVA and TPU; Prusa singles them out as the filaments most often in need of drying. But even PLA absorbs enough to cause trouble: Prusa notes that on the XL, with its multi-tool system, even PLA can take up enough moisture to create printing issues. The fix is not just any hot air but controlled drying at the right temperature and storage with desiccant.
Related terms
- Filament dryingDrying filament means holding it for hours at a temperature below its softening point so absorbed water evaporates before printing.
- StringingStringing is the fine threads of material left between parts of a print when the nozzle oozes during non-printing travel moves.
- FilamentFilament is the plastic thread wound on a spool that feeds FDM-type printers, normally 1.75 mm in diameter.
Updated
Sources
- [1]Drying filament | Prusa Knowledge BasePrusa Research · Manufacturer · accessed July 27, 2026