TPU Is the Filament Nobody Talks About Until They Need It

Everyone knows PLA and PETG. TPU (Thermoplastic Polyurethane) is the flexible filament that fills a niche nothing else can — rubber-like parts printed on a standard FDM printer.

Phone cases that actually protect. Drone bumpers that absorb crashes. Gaskets that seal. Vibration mounts that dampen. TPU handles all of it.

The problem: TPU is harder to print than rigid filaments. It’s soft and bendy, which means it can buckle in the extruder, jam in Bowden tubes, and string like crazy. The wrong TPU on the wrong printer is a nightmare. The right TPU on a direct-drive printer is surprisingly manageable.

Here’s what separates the good stuff from the frustrating stuff.

1. SainSmart TPU — Best Overall

⭐ Rating: 9.0/10 · $28-32/kg · Check Price on Amazon →

SainSmart TPU is the HATCHBOX PLA of the flexible filament world — the one everyone recommends because it consistently works. At 95A shore hardness, it’s the ideal balance between flexibility and printability.

Why it wins:

  • 95A hardness — Flexible enough for functional parts, rigid enough to feed through an extruder
  • ±0.03mm tolerance — Consistent diameter prevents jams from thick spots
  • Clean spool winding — Critical for flexible filament where tangles cause jams
  • Excellent layer adhesion — Parts feel solid, not layered
  • Prints at 220-230°C — Standard range, works on any all-metal hotend
  • Wide color selection — 15+ colors including clear and neon options

The catch: Still strings more than PLA or PETG — that’s just TPU. Not the softest option if you want truly rubber-like flex (look at 85A options for that). Costs about $10 more per kg than standard PLA.

Best for: First-time TPU users, phone cases, drone parts, functional flexible components. The default recommendation.

Print settings: 220-230°C nozzle, 50°C bed, 25-35mm/s print speed, 0.5-1mm retraction (direct drive).

2. NinjaTek NinjaFlex — Best Super-Flexible TPU

⭐ Rating: 8.7/10 · $42-48/kg

NinjaFlex is the OG flexible filament — the brand that pioneered printable TPU. At 85A shore hardness, it’s noticeably softer and more rubber-like than 95A options. If you want parts that feel like actual rubber, this is it.

Why it stands out:

  • 85A hardness — Genuinely soft and elastic, closer to rubber than plastic
  • 660% elongation at break — Stretches dramatically before failing
  • Excellent rebound — Parts return to original shape after compression
  • 12+ years on the market — The most refined TPU formula available
  • Great color range — Including translucent and specialty options

The catch: At $42-48/kg, it’s the most expensive filament on this list. The 85A softness makes it significantly harder to print — you need a direct drive extruder, very slow speeds (20-25mm/s), and almost no retraction. Bowden printers cannot print NinjaFlex.

Best for: Gaskets, seals, highly flexible phone cases, shoe insoles, vibration isolators — anything that needs true rubber-like flexibility.

Print settings: 225-235°C nozzle, 40-50°C bed, 20-25mm/s print speed, 0-0.5mm retraction (direct drive only).

3. OVERTURE TPU — Best Budget Option

⭐ Rating: 8.5/10 · $22-26/kg

OVERTURE delivers the same value proposition in TPU that they do in PETG — solid quality at a price that undercuts the competition. Their 95A TPU prints nearly as well as SainSmart at a 15-20% lower price.

Why it works:

  • $22-26/kg — Cheapest reputable TPU available
  • 95A hardness — Same practical flexibility as SainSmart
  • ±0.02mm tolerance — Excellent for the price
  • Good spool winding — Tangles are rare
  • Vacuum-sealed packaging — Arrives dry

The catch: Color selection is limited (5-6 options). Layer adhesion is good but not quite as strong as SainSmart or NinjaFlex. Some users report slightly more inconsistent flexibility between batches.

Best for: Budget-conscious users, prototyping flexible parts, high-volume TPU printing where per-kg cost matters.

Print settings: 220-235°C nozzle, 50°C bed, 25-35mm/s print speed.

4. Polymaker PolyFlex TPU95 — Best for High-Speed Printers

⭐ Rating: 8.4/10 · $30-35/kg

Polymaker’s PolyFlex is engineered for modern high-speed direct drive printers like the Bambu Lab series. Where most TPU maxes out at 30-35mm/s, PolyFlex can handle 50-80mm/s on well-tuned machines.

Why it’s notable:

  • Higher speed capability — Prints at 50-80mm/s on direct drive printers vs 25-35mm/s for most TPU
  • 95A hardness — Standard flexibility
  • Excellent documentation — Polymaker provides tested profiles for Bambu, Prusa, and other popular printers
  • ±0.02mm tolerance — Polymaker’s usual tight QC
  • Good color range — 10+ colors

The catch: More expensive than OVERTURE for similar hardness. The speed advantage only applies on modern direct drive printers — on older machines, it prints the same as any 95A TPU. Not as soft or elastic as NinjaFlex.

Best for: Bambu Lab and other high-speed printer owners who want to print TPU faster than typical.

Print settings: 215-230°C nozzle, 50°C bed, 50-80mm/s on direct drive (Bambu), 25-35mm/s on others.

5. eSUN TPU 95A — Best for Consistent Colors

⭐ Rating: 8.2/10 · $25-30/kg

eSUN’s TPU is a reliable mid-range option with one standout feature: their colors are vivid and consistent between batches. If you’re selling phone cases or products that need color accuracy, eSUN delivers.

Why it delivers:

  • Vivid, consistent colors — Neons, primaries, and pastels all look sharp
  • 95A hardness — Standard printability
  • Good layer adhesion — Solid part integrity
  • ±0.03mm tolerance — Reliable dimensional accuracy
  • Wide availability — Easy to source on Amazon

The catch: Average in most categories — not the cheapest, not the strongest, not the most flexible. Stringing is on the higher end for 95A TPU. Some users find it slightly stickier than SainSmart in the extruder.

Best for: Phone case businesses, colorful prototypes, any application where color accuracy and vibrancy matter.

Print settings: 220-235°C nozzle, 50°C bed, 25-35mm/s print speed.

TPU Printing Tips

TPU is different from rigid filaments. These tips prevent 90% of failures:

Printer Requirements

  • Direct drive extruder — Essential. Bowden tubes are the #1 cause of TPU failures. The flexible filament buckles in the long tube.
  • All-metal hotend — TPU prints at 220-235°C. PTFE-lined hotends work but are at their temperature limit.
  • Tight extruder path — Any gap between the drive gear and the nozzle is a spot where TPU can escape and jam.

Key Settings

  • Print slow — 25-35mm/s for 95A. 20-25mm/s for 85A. Speed is TPU’s enemy.
  • Minimal retraction — 0.5-1mm max for direct drive. Too much retraction causes jams. Some people disable retraction entirely for TPU.
  • No Z-hop — Z-hop gives more time for ooze. Disable it.
  • Lower acceleration — 500-1000mm/s² max. Sharp direction changes flex the filament.
  • Disable coasting — Coasting depends on consistent pressure, which TPU doesn’t provide.

Bed Adhesion

  • PEI sheets work best — TPU sticks well and releases cleanly
  • Blue painter’s tape is a solid backup
  • Glue stick on glass works but can make TPU too sticky
  • 40-60°C bed temperature is plenty

Post-Processing

  • TPU strings are inevitable — clean up with a heat gun on low, or carefully with scissors
  • Supports are very hard to remove from TPU — design parts to avoid supports when possible
  • TPU takes superglue (CA glue) well for multi-part assemblies

The Bottom Line

SainSmart TPU at 95A is the default. Reliable, affordable, and works on any direct drive printer. Start here.

For softer rubber-like parts, NinjaFlex 85A. For the cheapest option, OVERTURE. For speed on modern printers, Polymaker PolyFlex.

Make sure you have a direct drive printer before buying any TPU. If you’re on a Bowden setup, either upgrade the extruder or stick to rigid filaments.

Need a printer that handles TPU? The Bambu Lab A1 Mini and A1 both have direct drive extruders that print TPU reliably. For filament comparisons, check PLA vs PETG to understand where TPU fits in the material lineup.