TPU Printing on Snapmaker U1: Complete Guide
Comprehensive guide to TPU printing on Snapmaker U1: slicer settings, multi-material TPU+PLA printing, solving jams and bird-nesting issues.
The Snapmaker U1 is one of the few multi-material printers that genuinely handles TPU well. The key advantage is a direct drive extruder on each of its four toolheads. Unlike printers with AMS systems (Bambu Lab, Prusa), where flexible filament must travel through a long PTFE path with bends, the U1 feeds filament directly into the extruder. This dramatically reduces the risk of jams and allows stable TPU printing even during multi-hour projects.
Additionally, the U1 features oversized PTFE tubing with a larger internal diameter, which further reduces friction when feeding flexible materials. This means TPU slides through the filament path without resistance or kinking — exactly what you need for consistent extrusion.
However, multi-material TPU printing has its own pitfalls. Default slicer settings are designed for rigid filaments like PLA, and if you don't adjust them, you'll face jams, bird-nesting, and ruined prints. This guide covers all critical settings and common mistakes.
Preparing for TPU Printing
Drying Your Filament
TPU is extremely hygroscopic. Wet filament produces stringing, surface bubbles, inconsistent extrusion, and popping sounds during feeding. Always dry your TPU before every print session.
Recommended drying parameters:
| Parameter | Value |
|---|---|
| Temperature | 55-65 °C |
| Duration | 4-6 hours |
| Storage humidity | Below 25% |
For extended prints (24+ hours), use an external dry box connected directly to the printer. This prevents the filament from reabsorbing moisture during printing. The Snapmaker U1 allows convenient filament routing from a dry box to the rear of the machine.
Choosing Your Filament
The Snapmaker U1 is officially compatible with TPU at 90A Shore hardness and above. Softer variants (below 90A) may buckle in the extruder.
Recommended TPU brands for the Snapmaker U1:
- Polymaker PolyFlex TPU95-HF — the optimal choice. Shore hardness ~95-98A, high-flow formula (HF) enables print speeds up to 100 mm/s. Print temperature 200-220 °C.
- Siraya Tech TPU — community-tested for extended prints (24+ hours), including shoes and large models.
- Snapmaker TPU 95A — official filament with pre-loaded profiles in Snapmaker Orca. Dry at 65 °C.
Slicer Settings for TPU
Core printing parameters for TPU on the Snapmaker U1. Use Snapmaker Orca Slicer — it includes pre-configured profiles for TPU 95A HF that you can fine-tune.
| Parameter | Value | Notes |
|---|---|---|
| Nozzle temperature | 200-230 °C | TPU95-HF: 210 °C is a good starting point |
| Bed temperature | 25-50 °C | TPU adheres well even at low temps |
| Print speed | 40-80 mm/s | TPU95-HF can handle up to 100 mm/s |
| Layer height | 0.15-0.2 mm | 0.2 mm is optimal for strength |
| Retraction | 1-3 mm | No more than 3 mm for direct drive |
| Retraction speed | 20-30 mm/s | Low speed prevents jams |
| Max volumetric flow | 3-5 mm³/s | Reduce if experiencing extrusion issues |
| Walls | 2-3 | 3 walls provide strength for flexible parts |
| Infill | 10-20% | Gyroid or Cubic for flexibility |
Critical Parameter: Material Switching Retraction
This is the single most important parameter for multi-material TPU printing on the U1. During a toolhead change, the printer retracts filament by a set distance (Material Switching Retraction) to prevent oozing while parked. The default value is 10 mm, and this is far too much for TPU.
At 10 mm retraction, flexible filament curls around the extruder gears, loses grip with the feeding mechanism, and cannot be pushed back through on the next load. The result is a "no extrusion" error and a halted print.
Where to find this in Snapmaker Orca Slicer: open Filament Settings and look for Material Switching Retraction or Retraction distance when tool is disabled. Set it to 2-4 mm for TPU. If you still experience oozing, add a Wipe Tower instead of increasing retraction.
Extruder Gear Pressure
TPU is softer than PLA, and excessive gear pressure can deform the filament, causing inconsistent feeding. Loosen the side screw on the printhead to reduce gear pressure. The filament should pass through the extruder freely while still maintaining grip.
Multi-Material Printing: TPU + PLA
One of the U1's greatest advantages is printing TPU models with PLA supports. This solves a fundamental problem: TPU supports made from the same material fuse with the model, making removal nearly impossible without damaging the part.
Why PLA Supports Are Better
- Weak inter-material adhesion — PLA and TPU bond poorly to each other, making support removal easy and clean.
- Smooth bottom surface — after removing PLA supports, the TPU surface is significantly smoother than with TPU-on-TPU supports.
- TPU savings — PLA is cheaper and used only for supports, reducing expensive TPU consumption.
- Print stability — PLA prints predictably, producing rigid and accurate support structures.
Slicer Configuration
In Snapmaker Orca Slicer, go to the Support tab and select a separate extruder for supports. Assign TPU to the model (e.g., extruder 1) and PLA to supports (e.g., extruder 2).
Key settings for multi-material TPU + PLA printing:
| Parameter | TPU (model) | PLA (supports) |
|---|---|---|
| Nozzle temperature | 210-220 °C | 200-210 °C |
| Print speed | 40-60 mm/s | 60-80 mm/s |
| Material Switching Retraction | 2-4 mm | 6-8 mm |
| Regular retraction | 1-3 mm | 0.8-2 mm |
| Fan | 50-100% | 100% |
Community members have successfully printed full-sized shoes with PLA supports that peeled away cleanly, leaving smooth TPU surfaces.
Common Problems and Solutions
Jams During Toolhead Changes
Symptoms: the printer halts with a "no extrusion" error after switching to the TPU toolhead. Filament is stuck in the extruder and cannot be pushed through.
Causes and solutions:
- Material Switching Retraction too high. Reduce to 0-4 mm. This fixes 80% of TPU jam issues on the U1.
- Excessive gear pressure. Loosen the side screw on the printhead. TPU doesn't need strong clamping force.
- High filament path resistance. If using an external dry box, ensure the PTFE tube between it and the feeder doesn't create excessive resistance during retraction. In some cases, removing the intermediate tube helps.
- Heat creep. During toolhead parking, TPU in the melt zone can soften and deform. Ensure hotend cooling is functioning properly.
Bird-Nesting
Symptoms: filament forms a tangled ball ("nest") around the extruder gears or inside the filament path. Discovered when disassembling the extruder after a jam.
Cause: during long retraction, flexible TPU doesn't travel back up through the filament path cleanly. Instead, it curls into loops inside the extruder. The gears continue pulling, the filament wraps around them, and the extruder seizes.
Solutions:
- Reduce Material Switching Retraction to 0-4 mm (primary fix).
- Lower retraction speed to 20-25 mm/s.
- Reduce regular retraction to 1-2 mm.
- Loosen extruder gear pressure.
- Reduce max volumetric flow to 3 mm³/s.
Stringing
TPU is prone to stringing between parts of the model. While completely eliminating stringing is difficult, you can minimize it:
- Dry your filament thoroughly — wet TPU produces significantly more strings.
- Increase travel speed to 150-200 mm/s.
- Enable wipe in retraction settings.
- Try lowering nozzle temperature by 5-10 °C.
Poor Bed Adhesion
TPU generally adheres well to various surfaces, but if you experience issues:
- Use a smooth PEI build plate or glass with adhesive.
- Increase bed temperature to 50 °C for the first layers.
- Reduce first layer speed to 20-30 mm/s.
- Lower first layer height to 0.15 mm for better squish.
Summary
The Snapmaker U1 is an excellent printer for TPU thanks to its direct drive extruders and oversized PTFE tubing. Key rules for successful printing:
- Dry your TPU — 4-6 hours at 55-65 °C before every print.
- Reduce Material Switching Retraction to 0-4 mm — this is the key setting that prevents jams.
- Use TPU 95A or harder — Polymaker TPU95-HF is optimal for the U1.
- Print with PLA supports — they remove easily and save TPU.
- Loosen extruder gear pressure — TPU doesn't need strong clamping.
With the right settings, the U1 can print TPU reliably for 24+ hours without a single jam. Multi-material TPU+PLA printing unlocks possibilities unavailable on most consumer printers — from shoes to functional flexible parts with complex geometries.