TPU Explained: Flexible 3D Printing
Everything about TPU flexible filament: hardness ratings, applications, printer requirements and what TPU is best at.
TPU (thermoplastic polyurethane) is the rubbery, flexible filament that lets a 3D printer produce parts that bend, stretch and absorb impact. It's the material behind 3D printed phone cases, watch bands, gaskets, grommets, drone bumpers and shoe insoles.
Shore hardness — pick the right flex
TPU is sold by Shore hardness rating. The most common grades in Australia are:
Shore 95A — firm and slightly flexible, like a hard rubber shoe sole. Good for phone cases, watch bands, robust gaskets and any part that needs to flex slightly without distorting.
Shore 85A — significantly softer and stretchier, like a rubber band. Good for soft grips, seals and parts that need to compress and rebound.
Shore 70A — very soft, almost squishy. Specialist use only and harder to print.
When in doubt, 95A is the right default — it prints reliably on most printers and covers 80% of TPU applications.
What TPU is great at
Gaskets and seals, custom feet for furniture, drone bumpers, RC car tyres, phone and tablet cases, watch straps, replacement grommets and bushings, custom grips for tools, prosthetic liners, and pet toys. Anything that needs to compress, flex or absorb impact.
What TPU is not good at
Anything load-bearing in a structural sense. TPU is not a substitute for a metal bracket or a rigid plastic bracket — it will deflect under load. It is also slower and more expensive to print than PLA or PETG, so don't pick it 'just in case'.
Printing TPU
TPU needs a direct-drive extruder and slow print speeds (typically 20–40 mm/s). Most modern desktop printers from Bambu, Prusa and Creality handle it well; cheap older Bowden-tube printers struggle. When ordering, ask your maker whether they print TPU regularly — not every shop does.
Cost and lead time
Expect TPU prints to cost 1.5–2x the equivalent PLA part because of the slower print speed. Lead times are also slightly longer for the same reason.
FAQ
Is TPU waterproof?
Yes — TPU is naturally water and oil resistant, which makes it great for gaskets and seals.
Can TPU be food-safe?
Some TPU grades are food-contact rated, but the same layer-line bacterial concerns apply as with any FDM print. For occasional contact a food-safe coating is recommended.
What's the difference between TPU and TPE?
TPU is a specific type of TPE (thermoplastic elastomer). In 3D printing, 'TPU' is the term you'll see almost exclusively.
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