Polyurethane (PU) Elastomer Industrial Cast & Sheet Stock
Comprehensive technical specification for cast and sheet polyurethane elastomer (PU) used in Canadian fabrication, tooling, and wear-part manufacturing. Covers durometer ranges, standard sheet/rod sizing, machinability parameters, common casting defects, and storage guidelines for industrial shops.
Material Overview & Common Uses
Polyurethane (PU) elastomer is a thermoset polymer known for exceptional abrasion resistance, high load-bearing capacity, and excellent cut/tear strength. Unlike thermoplastic polyurethane (TPU), cast PU is cross-linked and cannot be re-melted, making it ideal for heavy-duty wear parts. Common Canadian shop applications include: press brake die pads (80-95A), conveyor belt scrapers, screen deck tensioners, mining chute liners, snow plow blade edges, forklift wheel treads, and custom jig/fixture pads. PU is also used as a vibration-dampening layer in press tooling and as a forming die material for sheet metal prototyping.
Core Technical Properties & Sizing
| Property | Value / Range |
|---|---|
| Durometer Range | 70A (soft) to 95A (hard) — common grades: 80A, 90A, 95A |
| Tensile Strength | 4,000–8,000 psi (27.6–55.2 MPa) |
| Elongation at Break | 250–600% |
| Tear Strength (Die C) | 400–1,000 pli (70–175 kN/m) |
| Abrasion Resistance (NBS Index) | 100–400 |
| Compression Set (ASTM D395) | 15–35% |
| Operating Temperature | -40°C to +80°C continuous (+120°C short-term) |
| Standard Sheet Size | 48″ x 96″ (1219 x 2438 mm) |
| Thickness Tolerance (< 1/2″) | ±0.010″ (0.25 mm) |
| Density | 1.10–1.25 g/cm³ |
Machinability, Tooling & Feeds
| Parameter | Recommendation |
|---|---|
| Tooling Material | Carbide or PCD-tipped; positive rake inserts |
| Turning Speed | 200–400 SFM (60–120 m/min) |
| Turning Feed | 0.005–0.015 IPR (0.13–0.38 mm/rev) |
| Milling Speed | 300–500 SFM (90–150 m/min) |
| Milling Feed | 0.002–0.006 IPT (0.05–0.15 mm/tooth) |
| Drilling Speed | 150–300 SFM (45–90 m/min) |
| Drilling Feed | 0.002–0.005 IPR (0.05–0.13 mm/rev) |
| Coolant | Water-soluble oil (5–8%) or air blast |
| Sawing Blade Speed | 200–400 FPM (60–120 m/min); 10–14 TPI |
| Laser Cutting | Not recommended (melts and fumes) |
Common Defects & Quality Control
| Defect / Check | Specification / Action |
|---|---|
| Durometer Variation | ±3A (reject if exceeded) |
| Surface Porosity | Pinholes >0.5 mm diameter |
| Shrinkage (24h @ 23°C) | <0.5% from nominal |
| Concentricity (Rod < 2″) | TIR <0.010″ |
| Straightness (Rod) | Bow <0.005″ per foot |
| Storage Life | 2–5 years (ideal conditions) |
Storage, Handling & Racking Guidelines
Store PU elastomer in a cool, dry environment (15–25°C, <60% RH) away from direct sunlight, ozone sources (electric motors, welders), and strong UV light. Do not store near solvents, oils, or chemicals.
- Sheets should be stored flat on pallets or in vertical racks with full-width support to prevent sagging.
- Do not stack more than 6 sheets high without interleaving with kraft paper or polyethylene film.
- Rod stock should be stored horizontally on racks with multiple support points (max 24″ spacing).
- For long-term storage (>6 months), wrap in black polyethylene to block UV.
- Avoid contact with copper or brass (catalyzes degradation).
- Allow material to acclimate to shop temperature for 24 hours before machining.