TPU · Thermoplastic Polyurethane
Bends, stretches, and bounces back.
TPU is a printable rubber — the only material in the shop that genuinely flexes rather than just tolerating a little give. Gaskets, phone cases, vibration mounts, cable strain reliefs, and anything that needs to squash and spring back belongs here. Every Bambu Lab printer has the direct-drive extruder flexible filament needs; what TPU asks for is dry filament and patience with print speed.
Prints firm, finishes soft
Soft TPU is hard to feed. MorPhlex prints like a firm 90A TPU your extruder can grip, then softens toward 75A once it cures: comfortable grips and insoles without the jams.
See MorPhlex →Starting points, not gospel — always check the specific spool's spec sheet or your slicer's built-in profile first.
Needs slow speeds and dry filament, and standard TPU can't use the AMS.
Low tensile strength, but very hard to tear or puncture.
Softens at moderate heat — the lowest heat resistance on this list.
The only genuinely bendable, rubber-like material on this list.
Outstanding abrasion and impact resistance.
TPU (thermoplastic polyurethane) is an elastomer, not a rigid plastic — most printable grades sit around 85A–95A Shore hardness, comparable to a shoe sole or a skateboard wheel. That softness is exactly why it needs a different approach at the printer: a flexible strand buckles anywhere the feed path is long or loose, which is why standard TPU runs from the external spool holder straight into the toolhead instead of through the AMS.
Printed TPU resists abrasion, oil, and repeated impact far better than any rigid filament, and it absorbs vibration instead of transmitting it — the reason it shows up in printer feet, drone motor mounts, and cable grommets. The cost is speed: fast travel moves and tight retraction settings that work fine on PLA will just stretch and jam TPU, so prints run slower and bridging/overhangs need real support.
Yes — every Bambu Lab printer uses a direct-drive extruder, which is what flexible filament needs. Load standard TPU from the external spool holder (not the AMS), dry it first, and start from Bambu Studio's TPU profile.
Almost always print speed. Fast travel moves and aggressive retraction cause TPU to buckle in the feed path. Slow down first before changing anything else.
Poorly, without support. It's soft enough that unsupported spans sag more than a rigid filament would — add supports for anything beyond a very short bridge.
Most general-purpose printable TPU sits around 95A (firmer, easier to print). Softer grades (85A and below) feel more like real rubber but are harder to print reliably — start at 95A unless you specifically need the extra give.
Standard TPU can't — Bambu Lab lists it as not compatible with the AMS or AMS lite, so feed it from the external spool holder. The exception is Bambu Lab TPU for AMS, a harder grade made to run through the AMS.
