Bambu Lab TPU 85A

Bambu Lab TPU 85A — flexible filament that actually feels flexible

TPU 85A is the softest filament in the Bambu Lab lineup. At Shore 85A it behaves far more like rubber than plastic: squeeze a printed part and it compresses, stretch it and it will go past 700% elongation before breaking, then return to shape. That makes it the material of choice for anything that needs to grip, seal, cushion or survive being dropped — phone and drone cases, gaskets and seals, RC tyres and bumpers, watch straps and wearables, tool grips, shoe soles, vibration-damping feet and flexible living hinges. It is a rewarding material for hobbyists, makers, schools and small businesses alike; the trick is simply to slow down and feed it properly.

Supplied on a 1.75mm, 1kg reusable spool, with two hardness options so you can match the feel your part needs.

Key features

Shore 85A — softest Bambu TPU >700% elongation at break 1.75mm ±0.03mm tolerance Direct-drive extruders 0.6mm / 0.8mm nozzle 1kg reusable spool Impact & abrasion resistant

Bambu Lab's quality control is what sets this apart from budget flexibles: a tight ±0.03mm diameter tolerance means consistent extrusion through a direct-drive hotend, where soft TPU is least forgiving. The spool is vacuum-sealed with desiccant and rides on a reusable high-temperature spool, so it is ready to print out of the box.

Print settings

• Nozzle temperature: 200–250°C (start around 230°C)
• Bed temperature: 30–35°C — a thin layer of glue stick is recommended for adhesion and easy release
• Print speed: under 200 mm/s is the rated maximum, but 20–40 mm/s gives far better results on soft TPU
• Cooling: fan on — cooling helps the soft extrudate set before the next layer lands
• Nozzle size: 0.6mm or 0.8mm recommended; 0.2mm, 0.4mm and high-flow nozzles are not supported
• Extruder: direct drive only — not compatible with AMS or AMS lite, so feed from an external spool holder
• Retraction: keep it short and slow to avoid the filament buckling in the extruder
• Drying: 70°C for 8 hours in a filament dryer or blast oven if the spool has been open a while

Compatible with Bambu Lab X1 series, P1 series and A1 series printers when run from an external spool holder, as well as any other direct-drive FDM printer — Prusa MK-series, Voron, Creality Ender 3 S1/K1 and similar. Bowden-tube printers are not recommended for 85A.

Specifications

Choose your option

Both options share the same print settings and the same 1.75mm / 1kg format — pick the hardness that suits the job:

TPU 85A — softest, most rubber-like TPU 90A — firmer, easier to print

Go with 85A for squishy, high-grip, high-cushion parts, and 90A when you want flexibility with a bit more structure and a more forgiving print.

Practical tips

Keep it dry. TPU absorbs moisture faster than PLA, and damp TPU prints with popping, stringing and a rough, foamy surface. Store the spool sealed with desiccant below 20% RH between prints, and if it has been sitting out, dry it at 70°C for 8 hours before you start a long job.

Slow down and shorten the path. The most common failure with 85A is the filament buckling in the gap between the extruder gears and the hotend. Run 20–40 mm/s, dial retraction right back, and feed from a spool holder that unwinds freely — a spool that drags will under-extrude. For parts that need to flex a lot, print at 15–30% gyroid infill with 2–3 walls rather than solid; it prints faster and gives a far nicer springy feel.