TPU filament is one of the most useful materials in 3D printing – but it can be genuinely frustrating when your settings are even slightly off. The good news? Most problems have simple fixes.
At 3D Radical Prints, we work with customers across Australia every week who run into these exact issues. This guide covers the most common flexible TPU filament printing problems, what causes them, and how to solve them clearly and practically.
What Makes TPU Filament Different?
TPU stands for Thermoplastic Polyurethane. It’s a rubber-like, flexible 3D printer filament used for parts that need to bend, stretch, or absorb impact – phone cases, shoe insoles, gaskets, cable protectors, grips, and custom seals are common examples.
Unlike rigid materials like PLA or PETG, TPU has a soft, elastic structure. This flexibility is exactly what makes it useful – and also what makes it sensitive to incorrect settings. The extruder can compress or buckle the filament if you push it too hard, too fast.
The Most Common TPU Printing Problems (And How to Fix Them)
1. Filament Jamming or Grinding
This is the number one complaint with flexible 3D printing filament. The filament loads fine, then grinds, slips, or jams mid-print. TPU is soft enough to compress under pressure – when print speed is too high, the extruder pushes filament faster than the hot end can melt it, causing it to buckle.
The fix: Slow down. This solves the problem most of the time. A print speed between 20–35mm/s is the safe range for most TPU blends. Direct drive extruders handle this far better than Bowden setups. If you’re using a Bowden printer (like many Creality Ender models), tighten up the PTFE tube path to reduce flex gap – or upgrade to a direct drive extruder.
2. Stringing Everywhere
Stringing – those thin spider-web threads between sections of your print – is extremely common with TPU rubber filament because it’s viscous and oozes while the nozzle moves.
The fix: Increase retraction slightly, but not too much – over-retraction causes its own jamming issues. 1 – 3mm works well for most direct drive setups. Raise travel speed to 150mm/s or above so the nozzle crosses gaps quickly. Lowering print temperature by 5–10°C can also help if you’re within the safe range for your blend.
3. Under-Extrusion and Weak Layer Adhesion
If your print looks sparse, gaps appear between lines, or layers peel apart easily, you’re likely under-extruding. With TPU printing filament, this is usually caused by printing too fast, too cold, or with overly aggressive retraction.
The fix: Raise your hot end temperature slightly – try 225–235°C for most standard TPU. Reduce retraction distance, lower print speed, and check that your extruder tension is firm but not crushing the filament. Soft filament deforms easily under too much grip pressure.
4. Warping or Lifting Off the Bed
TPU generally has decent bed adhesion, but in cold or draughty environments – common in Australian garages and workshops during winter – the first layer can lift or shift.
The fix: Print the first layer at 15–20mm/s and use a heated bed at 30–45°C. A light coat of glue stick or hairspray on a glass bed works well. Eliminate drafts near the printer – a simple enclosure made from cardboard or foam board makes a surprising difference in colder conditions.
5. Elephant Foot or Squished First Layer
Sometimes TPU is so soft that the first layer spreads out and forms a wide, flared base. The fix: raise your nozzle slightly by adjusting your Z-offset, and reduce your first layer extrusion multiplier to around 90–95%.
Best 3D Printer Settings for TPU Filament
There’s no single perfect setting – it varies by printer, brand, and Shore hardness. But here’s a reliable baseline for most standard TPU 3D printing filament:
- Print temperature: 220 – 235°C
- Bed temperature: 30 – 45°C (unheated beds can work too)
- Print speed: 20 – 35mm/s – start slow, increase only if stable
- Retraction: 1 – 3mm direct drive; 3 – 5mm Bowden (test carefully)
- Cooling: Minimal or off – TPU needs heat for proper layer bonding
- Infill: 20 – 40% for flexible parts; 80 – 00% for more rigid results
If you take one thing from this guide, slow down your print speed. The majority of TPU failures come back to this.
Which Printers Handle TPU Best?
Direct drive printers are the best choice for flexible filament 3D printing. The short, tight filament path from extruder to hot end leaves no room for buckling. If you’re still running a Bowden setup, a direct drive upgrade kit is one of the best investments you can make if flexible materials are a regular part of your workflow.
Storing TPU Filament – It Matters More Than You Think
TPU is hygroscopic – it absorbs moisture from the air. Wet filament causes bubbling, popping sounds, poor surface quality, and weak layer bonds. In humid Australian cities like Sydney, Brisbane, and Perth, this is a real and common issue.
Store your TPU in an airtight container or vacuum-sealed bag with silica gel desiccant. If it does absorb moisture, dry it in a food dehydrator or filament dryer at 45–55°C for 4–6 hours before printing.
Is TPU the Right Material for Your Project?
For most hobby, prototyping, and functional part applications, Shore 95A TPU filament is the right call. It’s tough, abrasion-resistant, chemical-resistant, and widely available. If you need extreme softness, TPE is an option, but it’s harder to print. For food-safe applications, specific compliant TPU grades exist.
Final Thoughts
Printing with TPU is far less intimidating once you understand what it needs – slower speeds, careful retraction, dry filament, and a direct drive printer if possible.
If you’re based in Australia and want filament that actually performs, browse our flexible TPU filament range for 3D printers – or get in touch and we’ll help you pick the right material for your next project.