Why moisture matters
TPU is hygroscopic. Absorbed water turns into steam during extrusion, causing popping, bubbles, surface roughness and a drop in mechanical strength.
Factory drying protocol
Every spool is dried before packaging, vacuum-sealed in foil bags with desiccant. Incoming raw material and final spools pass the same moisture-check gate.
Recommended user storage
Keep opened spools in a dry box at 10–30 % RH. For long-term storage, reseal in the original foil bag or use a vacuum bag with fresh desiccant. Avoid cold garages and humid basements.
When to dry again
If the printing room is humid (above 60 % RH) or spools have been opened for over a week, dry at 55–70 °C for 4–6 hours before use. Never exceed 80 °C — TPU can soften and fuse.
Contact us for a printable drying reference card for your workshop.