TPU Filament.
The flexible, rubber-like filament for functional parts that need to bend, stretch, compress, and absorb impact without breaking.
TPU (Thermoplastic Polyurethane) is a flexible 3D printing filament that stretches, bends, and absorbs impact like rubber. It comes in shore hardness ratings (typically 85A–95A for printable grades), prints best on direct-drive extruders at 220–240°C and 20–40mm/s (slow), and adheres strongly between layers. Best for phone cases, gaskets, drone bumpers, and wearables. Bowden extruders struggle with TPU — direct drive is strongly recommended.
Thermoplastic Polyurethane.
TPU — Thermoplastic Polyurethane — is a flexible, rubber-like filament used in 3D printing to create parts that bend, compress, and stretch. Unlike rigid materials like PLA or PETG, TPU produces prints with elastic properties similar to rubber, silicone, or dense foam.
Shore hardness defines how soft or rigid a TPU is. The standard in 3D printing is shore 95A — roughly the firmness of a shoe sole or cart wheel. Softer variants (85A) feel like a gummy bear and are extremely elastic but difficult to print. Stiffer variants (98A) approach semi-rigid territory and feed much more reliably through an extruder.
TPU is used wherever parts need to absorb shock, seal against surfaces, grip objects, or flex repeatedly without cracking. Phone cases, drone bumper guards, gaskets, wearable devices, vibration dampeners, and custom shoe insoles are all classic TPU applications.
The trade-off is print speed and difficulty. TPU requires slow speeds (20–30mm/s), a direct drive extruder for reliable feeding, and careful retraction tuning. It rewards patience — and the results are parts no rigid filament can replicate.
What Makes TPU Unique.
Elastic & Flexible
TPU stretches up to 500% before breaking and returns to its original shape. No rigid filament comes close to this level of elasticity — it is the defining property of TPU.
Impact & Abrasion Resistant
TPU absorbs impacts like rubber and resists wear better than most FDM materials. Drone bumpers, phone cases, and protective covers leverage this combination of toughness and flexibility.
Shore Hardness Options
From soft 85A (gummy, elastic) to firm 98A (semi-rigid), TPU comes in a spectrum of hardnesses. Shore 95A is the sweet spot — flexible enough to be useful, stiff enough to print reliably.
Vibration Dampening
TPU absorbs vibration and noise rather than transmitting it. Motor mounts, anti-vibration feet, and equipment isolators are all ideal applications for flexible prints.
Chemical & Oil Resistant
TPU resists oils, greases, and many solvents — making it suitable for gaskets, seals, and industrial grips that contact automotive or mechanical fluids.
Excellent Layer Adhesion
TPU bonds to itself extremely well during printing. The resulting parts have strong inter-layer adhesion, meaning flexible prints rarely delaminate even under repeated bending and stretching.
Tuning TPU for Reliable Prints.
TPU is one of the slowest and most demanding filaments to print. The filament is soft and compressible, which means it can buckle inside the extruder if pushed too fast. A direct drive extruder is strongly recommended — Bowden setups add a long tube where flexible filament compresses and jams.
Retraction is the most critical setting. Too much retraction causes the soft filament to tangle inside the extruder. Too little causes extreme stringing. Start with minimal retraction (0.5–2mm on direct drive) and increase only if needed. Many experienced users disable retraction entirely for TPU and rely on coasting and travel speed to manage ooze.
Slow print speeds are non-negotiable. At 20–30mm/s, TPU feeds smoothly and layers bond well. Push beyond 40mm/s and you risk the filament buckling, grinding, or jamming — especially on softer variants below 95A.
- Nozzle temp: 220–240°C (start at 230°C)
- Bed temp: 50–60°C (painter's tape or PEI surface)
- Print speed: 20–30mm/s (never rush flexible filament)
- Retraction: 0.5–2mm direct drive / avoid on Bowden
- Travel speed: 150mm/s+ (fast travel reduces stringing)
- Cooling fan: 50–100% (TPU tolerates cooling well)
- Layer height: 0.2–0.3mm (thicker layers print more reliably)
- Infill: 10–20% for flexibility, 50%+ for rigidity
- Flow rate: 100–105% (slight over-extrusion improves sealing)
TPU Compared to Other Flexible Filaments.
TPU 95A (Standard)
The default flexible filament. Balances printability with useful flexibility. Prints at 20–30mm/s on direct drive. This is what most people mean when they say "flexible filament."
TPU 85A (Soft)
Significantly softer and more elastic — like a rubber band. Very difficult to print: requires sub-20mm/s speeds, direct drive only, and zero retraction. Reserved for experienced users needing extreme flex.
TPU 98A (Firm)
Semi-flexible, almost rigid. Easier to print than softer variants and works on some Bowden setups. Good for parts needing slight give — tool grips, bumper inserts, or stiff protective covers.
TPE (Generic Flexible)
TPE is a catch-all term for flexible thermoplastics. "TPE" labeled filaments are often softer than 95A TPU and harder to print. If a product just says "TPE" without a shore rating, expect a learning curve.
Soft PLA (PLA Flex)
Some brands sell a "flexible PLA" that is slightly bendy but not truly elastic. These are easier to print than real TPU but have limited stretch and poor recovery. Not a substitute for genuine TPU.
When Rigid Is Better
If your part needs structural strength rather than flexibility, use PLA or PETG. TPU is not a general-purpose material — it excels specifically where parts must bend, compress, or absorb shock. For rigid functional parts, PETG is the better choice.
Why TPU Quality Matters Even More.
Flexible filament amplifies every quality problem. Because TPU is soft and compressible, inconsistent diameter causes immediate feeding issues — the filament either jams or under-extrudes in sections where it is too thick or too thin. With rigid filament you might not notice a ±0.05mm variance; with TPU, you will.
Forgely TPU is manufactured and spooled in Ogden, Utah, with ±0.02mm diameter tolerance. Consistent diameter means the filament feeds predictably through the extruder, which is the single most important factor in successful TPU printing.
Moisture is another critical factor. TPU absorbs water readily, and wet TPU produces bubbling, popping, poor surface finish, and weakened layer bonds. Forgely TPU ships vacuum-sealed with desiccant and is never exposed to ocean freight humidity. Fresh, dry filament straight from production to your printer.
If you have struggled with flexible filament before, the filament quality may have been the problem — not your printer or settings. Consistent, dry TPU from a domestic source eliminates the most common failure modes before you even start a print.
Common TPU Issues — Quick Fixes.
The number one TPU failure is filament jamming or buckling in the extruder. This happens when the feed rate exceeds what the soft filament can handle. If your extruder is grinding or clicking, slow down — 20mm/s is not an arbitrary suggestion, it is the ceiling for reliable flexible printing on most setups.
Stringing is the second most common complaint. TPU oozes constantly at printing temperatures because it stays semi-liquid longer than rigid filaments. Accept that some stringing is normal with TPU and plan for post-processing — a heat gun at low setting cleans up strings in seconds.
- Jamming/buckling: Reduce speed to 20mm/s, ensure direct drive, check for gaps in filament path
- Stringing: Increase travel speed 150mm/s+, minimize retraction, enable coasting
- Under-extrusion: Increase flow 3–5%, check for partial clog, slow print speed
- Poor bed adhesion: Use painter's tape or glue stick, increase bed temp to 60°C
- Blobs at seams: Reduce retraction prime, enable wipe, use "random" seam placement
- Warping corners: Increase bed temp, add brim 5mm+, reduce cooling on first layers
Frequently Asked.
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Ready to Print Flexible?
Forgely TPU. Made in Utah. ±0.02mm tolerance. Shore 95A. Consistent feed, minimal stringing when dialed in.
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