GLOSSARY
TPU Filament
TPU (thermoplastic polyurethane) is the rubber-like flexible filament. It bends, stretches, and rebounds — perfect for gaskets, grips, shoe soles, and phone cases.
Definition
TPU is a thermoplastic elastomer — a plastic that behaves like rubber but melts and re-solidifies cleanly. It comes in different hardness grades on the Shore A scale: 95A is firm (like a skate wheel), 85A is medium-soft (like a phone case), 75A is squishy (like a stress ball). Most desktop printers handle 95A reliably; softer grades demand a direct-drive extruder.
Print temperatures sit around 220–240°C with a slow speed — flexible filament buckles in the extruder if you push it fast.
Why it matters
TPU is the only common filament that survives repeated bending and impact. Use it for gaskets, vibration dampers, drone bumpers, watch bands, footwear inserts. It is also good for press-fit grips because it conforms slightly under load.
Common confusion
Bowden-tube extruders struggle with TPU — the long PTFE tube gives the soft filament room to compress and bind. Direct-drive (extruder mounted on the toolhead) is strongly recommended for anything below 95A.
TPU does not glue or solvent-weld easily, and most household adhesives peel off. Plan for mechanical fastening or interlocking geometry rather than bonding.