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TPU
TPU (Thermoplastic Polyurethane) is a versatile elastomeric thermoplastic that spans the performance gap between rigid engineering plastics and soft rubbers. Its defining characteristic is an exceptionally wide hardness range — from flexible Shore A 70 to rigid Shore D 60 — achieved by varying the ratio of hard and soft segments in the polymer structure. TPU combines high elasticity and elongation with outstanding abrasion resistance, excellent tear strength, and good load-bearing capacity, making it indispensable for applications requiring both flexibility and durability. It bonds well to metals and fabrics, supports overmolding, and is available in transparent, colored, and specialty grades for medical, food-contact, and flame-retardant applications.
Mechanical Properties
- Density: 1.12–1.25 g/cm³ (varies with hardness grade)
- Tensile Strength: 35–55 MPa (varies with hardness grade)
- Yield Strength: N/A — elastomeric behavior, no distinct yield point
- Elongation at Break: 300–700% (varies with hardness grade)
- Flexural Modulus: 20–700 MPa (depends on hardness; softer grades feature lower modulus)
- Hardness: Shore A 70 to Shore D 60 (varies by grade)
- Heat Deflection Temperature: 50–80°C @ 0.45 MPa (reinforced grades up to 110°C)
- Melting Point: 170–210°C (processing range)
- Thermal Conductivity: 0.20 W/m·K
- Coefficient of Thermal Expansion: 10.0–15.0 × 10⁻⁵ /°C (varies with hardness and fillers)
Advantages
🟢 Exceptional abrasion resistance — one of the highest among thermoplastics (Taber abrasion: 15–30 mg loss vs 50–100 mg for many rubbers), ideal for high-wear applications like shoe soles and conveyor belts
🟢 Extremely wide hardness range (Shore A 70 to D 60) — a single material family covers applications from soft grips to rigid structural parts, simplifying supply chains
🟢 Excellent elasticity and resilience — high recovery from deformation, low compression set, and good dynamic performance in repeated flexing and impact applications
🟢 Outstanding overmolding and bonding capability — adheres well to metals, ABS, PC, and fabrics without adhesives, enabling multi-material designs in a single mold
Machining & Manufacturing
| Parameter | Specification | Notes |
| Cutting Speed | Turning: 100–200 m/minMilling: 300–800 RPM (Ø6–Ø12 mm end mills) | Low speed is required; high speed leads to material deflection instead of clean shearing |
| Tooling | Ultra-sharp carbide tools, 15°–25° high positive rake, minimal edge hone & polished flutesShore D grades: standard carbide toolsShore A grades: dedicated elastomer cutting tools | Prevents galling and material sticking |
| Coolant | Preferred: Cryogenic cooling (liquid CO₂ / nitrogen)Conventional: Minimal flood coolant or air blast | Excessive coolant will cause material swelling |
| Chip Control | Stretchy elastic chips prone to wrapping around tools | Adopt turning feed 0.2–0.5 mm/rev and deep cuts; vacuum chip removal is recommended |
| Surface Finish | Cryogenic machining: Ra 1.6–3.2 μmConventional machining: Ra 3.2–6.3 μm | Use sharp tools and light finishing cuts for better surface quality |
| Fixturing | Soft jaws, vacuum fixtures or custom cradles | Spread clamping force over large areas; avoid sharp clamps to prevent local deformation |
Common Applications
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