TPU (Flexible thermoplastic polyurethane)
Frequently asked questions
Can TPU (Flexible thermoplastic polyurethane) be laser cut?
With some limitations: TPU (Flexible thermoplastic polyurethane) can be laser cut. Adequate extraction/ventilation is required.
Can TPU (Flexible thermoplastic polyurethane) be CNC machined?
With some limitations: TPU (Flexible thermoplastic polyurethane) can be CNC machined.
Can TPU (Flexible thermoplastic polyurethane) be 3D printed?
Yes, using FDM.
Is TPU (Flexible thermoplastic polyurethane) food safe?
No, TPU (Flexible thermoplastic polyurethane) is not considered food safe.
Physical properties
| Density | 1100.0–1250.0 kg/m³ |
|---|---|
| Tensile strength | 40.0 MPa |
| Glass transition (Tg) | -30.0 °C |
| Thermal expansion | 150.0 µm/m·K |
| Moisture absorption | Low |
Laser processing
Thermal degradation of TPU releases isocyanates and aromatic amines, which are irritating to the respiratory tract. In significant quantities, isocyanates are sensitizers (can cause occupational asthma). Forced ventilation to the outside recommended.
CO₂: CO2 laser cutting is possible on thin sheets, but the material tends to melt, stretch, and shrink around the kerf instead of vaporizing cleanly. Results vary widely depending on the Shore hardness of the TPU. Harder grades (Shore 95A+) perform better. Edges tend to melt.
Diode: Not recommended. Heat build-up causes deformation and makes controlled melting impossible.
Fiber: Surface marking possible on dark TPU. Not for cutting.
CNC / milling processing
Difficult CNC machinability: the material is too flexible to be held stably and tends to deform under the tool instead of being removed. Possible for rigid grades (Shore 95A+) with very robust fixturing. Not recommended for complex geometries.
3D printing
Plotter and thermoforming
Cuttable with a blade plotter (Cricut, Silhouette) for softer grades in thin sheet form (0.5–2 mm). Flexibility requires a firm adhesive carrier to prevent the sheet from slipping. Standard vinyl blade, low speed, high pressure.
Post-processing
Sanding: Not effectively sandable: the material is elastic and the abrasive paper bounces instead of removing material. Prefer trimming with a utility knife or direct finish from printing.
Primer: Standard paints do not adhere well to TPU due to its elasticity. Use flexible polyurethane-specific coatings or paints for shoe soles.
Gluing: Bondable with flexible polyurethane adhesives (e.g., Bostik, Sika) or cyanoacrylate for flexible rubbers. Joints must be as elastic as the material to avoid breaking under flex.
Over time: Excellent resistance to abrasion, lubricants, and oils. Good UV resistance compared to other elastomers. Tends to lose elasticity at very low temperatures (below –20 °C for soft grades).
Common defects
- Difficult to print with Bowden extruders — the filament bends and compresses in the flexible path; direct extruders preferred
- Absorbs moisture — wet filament produces prints with bubbles and rough surface
- Difficult post-processing due to elasticity
Safety
Recommended PPE: mask_p2
Safe in solid state. Fumes during FDM printing or laser cutting contain isocyanates at low concentration: ventilate the area. Those suffering from occupational isocyanate asthma should use respiratory protection.
Availability and formats
Commercial formats: filament 1.75mm, filament 2.85mm, sheets 0.5–5mm, granules
Related materials
Sources
- ISO 37 — Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties
- Covestro Desmopan — Technical data sheet
- Datasheet tecnici Fillamentum Flexfill TPU 98A
Information on compatibility, processing parameters and safety is purely indicative. MakerSpecs accepts no liability for damage to persons or property arising from the use of this data. Always check the safety rules and the manufacturer's official manuals before carrying out any processing.