Printing Conditions & Material Overview
Flexible filaments like TPU are known for durability and elasticity, However, they also come with a well-known limitation: printing speed.
Traditional TPU 3d filaments typically require slow print speeds, often between 30 mm/s and 80 mm/s, because flexible materials are more difficult to extrude and control during printing.
With the development of high-flow flexible filaments, this limitation is gradually changing.
In this lab test, three different printing conditions were tested, gradually increasing both print speed and maximum volumetric speed, with speeds reaching up to 250 mm/s. This article presents the results, recommended settings, and best practices for reliable high-speed TPU printing.
Test Setup & Printing Conditions
To evaluate the performance of TPU 95A HF under high-speed conditions, three different parameter profiles were tested while keeping the temperature settings constant. (Condition 1 formula is compatible with Bambu printer)
| Parameter | Condition 1 | Condition 2 | Condition 3 |
| Environment | Open frame | Open frame | Open frame |
| Nozzle Temp | 230°C | 230°C | 230°C |
| Bed Temp | 35°C | 35°C | 35°C |
| Printing Speed | 134mm/s | 200mm/s | 250mm/s |
| Max Volumetric Speed | 12mm³/s | 18mm³/s | 23mm³/s |
Basic Material Properties of TPU 95A HF
- Density: 1.21g/cm³
- Melting Point: 133.5°C
- Tensile Strength: 20.58MPa
- Elongation at Break: 548.66%
- Young’s Modulus: 3.56 MPa
- Unnotched Impact Strength: 51.46kJ/m²
- Notched Impact Strength: 37.63kJ/m²
These properties make the material suitable for flexible functional parts, protective components, and impact-resistant applications.
High-Speed TPU 95A Printing Results
Condition 1: Default Parameters
- Printing Speed: 134mm/s
- Max Volumetric Speed: 12mm³/s
Result:
The default settings produced a high-quality model with smooth surfaces. Ideal for general prototyping and test prints.
Condition 2: Increased Volumetric Speed & Printing Speed
- Printing Speed: 200mm/s
- Max Volumetric Speed: 18mm³/s
Result:
Printing small models remains accurate, minor stringing was observed, which can be post-processed.
Overall quality is within acceptable limits.
Recommended for users who want faster prints without significant quality loss.
Condition 3: Maximum Volumetric Speed & Printing Speed
- Printing Speed: 250mm/s
- Max Volumetric Speed: 23mm³/s
Result:
Small models may show slight stringing or minor surface imperfections.
This represents the upper limit of printing speed for TPU 95A HF in this test environment.
Post-processing may be required depending on tolerance for minor defects.
Suitable for high-speed prototyping when speed is prioritized over surface perfection.
Tip: Always adjust cooling and extrusion settings based on your printer and model complexity.
Why TPU Filament Must Be Dried Before Printing?
3D printing TPU is a hygroscopic material, meaning it easily absorbs moisture
from the surrounding air. Moist TPU can cause several print defects:
- Excessive stringing
- Bubbling during extrusion
- Weak layer adhesion
- Surface roughness
For best results, dry TPU filament at 60-80°C for 5-8 hours. Proper drying dramatically improves print quality and extrusion stability. For long-term storage, keep filament in sealed bags with desiccant.
Important TPU Printing Tips
📍 Reduce Feeding Resistance
TPU materials have inherent elasticity and surface stickiness. If excessive resistance occurs during filament feeding, it may lead to:
- Slipping in the extruder
- Inconsistent feeding
- Print failure
To minimize feeding resistance:
- Ensure the spool rotates smoothly
- Reduce friction in the filament path
- Avoid sharp bends in the guide tube
Maintaining a smooth filament path ensures stable material delivery to the extruder.
📍 Nozzle Compatibility Matters
When printing with TPU, nozzle selection is critical. Some configurations may increase extrusion resistance and cause clogging.
Important considerations:
0.2 mm nozzles are not recommended for TPU printing.
High-flow nozzles may also cause unstable extrusion with flexible materials.
TPU 85A materials may not perform well even with 0.4 mm nozzles due to their softness.
Another important factor is nozzle contamination. If the hotend was previously used to print carbon-fiber-reinforced or glass-fiber-reinforced filaments, residual fibers may remain inside the nozzle, which significantly increase extrusion resistance and can easily cause clogging when printing TPU. Before printing TPU with such nozzles, it is recommended to perform 3–5 cold pulls to remove internal residue.
Common TPU Printing Issues and Solutions
| Issue | Possible Cause | Solution |
| Stringing | Moist filament or excessive retraction | Dry filament and reduce retraction |
| Weak layer bonding | Insufficient temperature or moisture | Dry filament and adjust nozzle temperature |
| Over-Extrusion | Excessive volumetric speed | Reduce volumetric speed, Slow down print speed if needed |
| Feeding issue | High path resistance | Improve spool rotation and filament path |
Printing at 250 mm/s is achievable but may produce minor defects. Users should decide based on acceptable tolerance for surface quality and post-processing needs.
Conclusion
High-speed TPU materials are redefining what flexible filaments can do. Our test shows that TPU 95A HF can reliably print at speeds up to 200 mm/s, with extreme testing reaching 250 mm/s.
With proper drying, optimized volumetric speed, and minimal retraction, users can achieve both flexibility and high productivity.
If you want to learn more about TPU materials, printing techniques, and filament selection, read our complete TPU Filament Guide.
