TPU Filament: The Complete Printing Guide

What Makes TPU Different

TPU (Thermoplastic Polyurethane) is a rubber-like flexible filament used for parts that need to compress, flex, grip, or absorb impact. Unlike PLA or PETG, which break under deformation, TPU bounces back. But that flexibility is also what makes it one of the more demanding materials to print — the same properties that let it bend also make it want to buckle in your extruder.

Understanding Shore Hardness

Shore hardness describes how firm a flexible material is. For 3D printing filaments, the Shore A scale is what matters:

• Shore 85A–87A: Very soft, gel-like. Like a soft rubber band. Used for phone case edges, soft grips.
• Shore 95A: Firm but pliable. Like a car tire tread. Holds shape under light load but flexes under pressure. Best all-around choice for most applications.
• Shore 98A and above: Semi-rigid. Barely flexible. Closer to hard plastic in feel.

Filora TPU is 95A — the most versatile option. It is firm enough to hold dimensional accuracy in a phone case or gasket, but flexible enough to absorb impact and compress under load.

Direct Drive vs Bowden: Why It Matters More for TPU Than Any Other Material

Flexible filament is not a rigid rod — it is a flexible strand that can buckle in the feed path under backpressure. On a Bowden setup (where the extruder is mounted away from the hotend), the long PTFE tube between extruder and nozzle allows the filament to compress and coil when retraction occurs or print speed gets too high.

Direct drive extruders (Bambu, Prusa MK4, Voron, Ender 3 with a direct drive kit) mount the extruder directly above the hotend with minimal gap. This eliminates most of the Bowden path, giving the extruder direct control over the filament.

If you have a Bowden printer: TPU is possible but requires very low print speeds (15–20mm/s), near-zero retraction, and patience. Budget 2–3 failed test prints to dial in settings.

If you have a direct drive printer: TPU at 20–40mm/s is straightforward.

Print Settings for TPU 95A

• Nozzle temp: 220–240°C (225°C is a good starting point)
• Bed temp: 30–60°C (no heated bed needed, but a warm bed improves first layer adhesion)
• Print speed: 20–40mm/s — this is non-negotiable. Faster speeds cause compression and jams.
• Retraction: 0–1mm on direct drive. More retraction increases buckling risk.
• Cooling: Minimal to moderate. TPU does not need aggressive cooling the way PLA does.
• Infill: Gyroid or honeycomb for flexible parts. Higher infill percentage produces a stiffer final part.

Common TPU Problems and Solutions

Extruder Jam or Filament Grinding

Cause: Print speed too high, causing backpressure that buckles the filament upstream of the extruder gear.
Fix: Reduce speed to 20–25mm/s. Reduce retraction. Check for any gaps in the filament path where the flexible filament can escape and coil.

Spaghetti or Under-Extrusion

Cause: The extruder cannot keep up with commanded speed, or the hotend temperature is too low.
Fix: Increase temp to 235–240°C. Lower speed. On Bowden setups, some under-extrusion is expected — run slower and accept slightly more stringing.

Stringing

TPU strings. Enable combing mode to route all travel moves over filled areas. Keep travel speed high (150–200mm/s). Post-print stringing on TPU is easy to remove — just pull the strings off; they peel cleanly from the flexible surface.

Poor Layer Adhesion or Delamination

Cause: Temperature too low, or speed too high for adequate bonding time.
Fix: Print at 235–240°C. Reduce speed. Increase perimeter count — 3–4 perimeters give much better flex durability than 2 for parts that will be repeatedly flexed.

Best Use Cases for Shore 95A TPU

• Phone cases — absorbs drop impact, flexible for removal from device
• Cable strain reliefs — prevents cable bending at connectors
• Gaskets and seals — compresses to form a watertight seal
• RC car bumpers and tires — survives crashes that crack rigid parts
• Tool grips and handles — soft-touch surface over a rigid substrate
• Shoe insoles and orthotics — custom support with controlled compression
• Robot feet and bumpers — grip and impact absorption in one print

Quick Start Checklist

Before printing your first TPU part: verify you have a direct drive extruder, set speed to 25mm/s, disable retraction or set to 0.5mm maximum, use 225°C nozzle temp, enable combing mode. Print a simple calibration cube first to confirm settings before committing to a long print. TPU rewards patience on the setup run.