TPU Flexible Filament Review - Best Brands and Performance

TPU (thermoplastic polyurethane) is the flexible filament that actually flexes—not the rubbery-feeling stuff that’s actually just soft plastic. Real TPU printing is finicky but worth learning for functional projects.

What is TPU vs. TPE

TPU (Thermoplastic Polyurethane): True elastomer, survives thousands of flexes, genuine flexibility, print-challenging

TPE (Thermoplastic Elastomer): Softer, easier to print, but not as durable, less true flex

Most budget “flexible” filament is TPE. Real TPU costs more but delivers genuine durability.

For this review, all recommendations are TPU.

Print Temperature Requirements

This is the first major hurdle. TPU needs specific conditions:

Nozzle temperature: 220-240°C (material-dependent)

• Too cool: Doesn’t flow, weak prints
• Too hot: Oozes excessively, stringy prints

Bed temperature: 60-70°C (critical for adhesion)

• Too cool: Warps, peels off during print
• Too hot: Over-adheres, impossible to remove

Extruder type matters:

• Direct drive: Works well with TPU (short feed distance)
• Bowden: Can work but requires more careful settings

Print Speed — The Primary Limitation

TPU must print slow. Very slow.

Practical speeds:

• 40-50mm/s: Reliable, good quality
• 60mm/s: Possible but risky
• 70mm/s+: Usually fails or produces poor quality

A 100g model that prints in 30 minutes in PLA takes 1+ hours in TPU.

Why: TPU flows easily when hot, meaning if you move too fast, the filament can’t extrude consistently. It’s not the printer’s limitation—it’s the material physics.

Retraction Settings

Standard retraction doesn’t work well with TPU. The material gets damaged or kinked.

Correct TPU retraction:

• Distance: 4-5mm (less than PLA)
• Speed: 25-30mm/s (slower than PLA)
• Z-hop: 0mm (disabled; usually causes issues with TPU)

Over-aggressive retraction shreds the filament. Under-retraction causes oozing. You’ll need to tune this per brand.

Bed Adhesion Challenges

TPU adhesion is inconsistent. A clean bed helps immensely.

Best adhesion surface:

1. Clean heated glass with glue stick
2. PEI sheet at 65-70°C (warm end of range)
3. Bare aluminum (less ideal but works)

Avoid:

• Textured spring steel (TPU sticks too hard, rips chunks off prints)
• Cold bed (warping is severe)

Pro tip: Print slower for the first layer (30mm/s). It gives adhesion time to develop.

Brand Comparison

Tested brands (50g test prints):

Ninjatek (TPU 95A) — Industry standard

• Easiest to print, most forgiving
• Consistent quality across batches
• $30/kg
• Recommendation: Best for beginners

Overture TPU — Reliable alternative

• Similar to Ninjatek, slightly more stringy
• $25/kg
• Recommendation: Good value

MatterHackers TPU — Excellent but expensive

• Best quality prints, least tuning needed
• $35/kg
• Recommendation: If budget allows

Generic TPU (AliExpress, $15/kg) — Avoid

• Batch-to-batch inconsistency is severe
• Requires extensive tuning
• Not worth the savings

Verdict: Ninjatek is the safe choice. You’ll waste less time troubleshooting.

Durometer (Hardness) Levels

TPU comes in different hardnesses:

• 95A (softest): Phone cases, shock absorption, flexibility is priority
• 85A (medium): Shoe soles, seals, balance of flex and durability
• 75A (hardest): Wear-resistant, less flexible but tougher

Start with 95A for projects requiring genuine stretch. 85A for durability projects.

Real-World Failures

Stringing: Most common. Slow down print speed or increase retraction slightly.

Poor adhesion: Almost always bed temperature. Increase to 70°C.

Weak prints: Either nozzle temperature too low or print speed too high.

Lumpy surface: Inconsistent extrusion. Usually a tuning issue, not a material issue.

Most failures are fixable with incremental adjustments.

Use Cases Where TPU Excels

Phone cases: Flexible enough to install on phone, durable over 2+ years Shoe soles: Absorbs impact, outlasts rubber in many cases Seals and gaskets: Compresses into place, doesn’t harden Replacement parts: Shock-absorbing feet for electronics

Use cases where TPU fails:

• Structural parts (not strong enough)
• Rigid mounting brackets (use PETG instead)
• Large unsupported spans (sags under own weight)

Cost vs. Durability

A 100g flexible phone case costs:

• TPU material: $3-4
• Printing time: 1+ hours (expensive in labor if production work)
• Durability: 2+ years with normal use

vs. Rigid PETG case:

• Material: $1-2
• Print time: 30 minutes
• Durability: 1 year (more likely to crack)

For single prints, TPU is worth it. For production, the slow speed hurts profitability.

Moisture Sensitivity

Unlike nylon, TPU doesn’t absorb moisture. You don’t need special storage, but keep it sealed to avoid dust.

Sanding and Post-Processing

TPU can be sanded, but it’s finicky. Light sand only (220+ grit). Heavy sanding deforms the material.

Paint adhesion is poor. If you need to paint TPU, use flexible paint or leave it untreated.

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TPU is a genuinely useful material for the right projects. Print it slow, dial in temperature carefully, and you get excellent flexible parts. The effort is worth it if you’re making phone cases or flexible seals. For other projects, PETG is usually better.

Rating: 7/10 — Excellent when it works, frustrating when it doesn’t. Steep learning curve, but worthwhile.