Polycarbonate Sheet (Lexan / Makrolon) – Technical Material Specification for Canadian Fabrication
Comprehensive technical specification for polycarbonate sheet (Lexan/Makrolon) covering Canadian stock sizes, tolerances, machinability, common defects, and handling guidelines for industrial fabrication and woodworking operations.
Material Overview & Common Uses
Polycarbonate sheet, commonly known by the brand names Lexan (SABIC) and Makrolon (Covestro), is an amorphous thermoplastic with exceptional impact resistance (250x that of glass, 30x that of acrylic) and a service temperature range of -40°C to +125°C. It is inherently UV-resistant when coated, self-extinguishing (UL94 V-2 to V-0), and offers light transmission up to 89% in clear grades. In Canadian fabrication shops, polycarbonate is used for machine guards, safety glazing, skylights, greenhouse panels, thermoformed enclosures, CNC router vacuum-formed parts, and high-strength signage. It is also specified for cold-climate applications due to its low-temperature toughness and dimensional stability.
Core Technical Properties & Sizing
| Property | Value / Specification |
|---|---|
| Standard Sizes (Canadian Stock) | 48"x96", 60"x96", 48"x120", 60"x120" |
| Thickness Range | 0.030" (0.76 mm) to 0.500" (12.7 mm) |
| Thickness Tolerance | ±10% (ASTM D3935) / ±5% (Premium Optical) |
| Density | 1.20 g/cm³ (0.043 lb/in³) |
| Tensile Strength (Yield) | 9,000–10,500 psi (ASTM D638) |
| Flexural Modulus | 340,000–400,000 psi (ASTM D790) |
| Impact Strength (Izod Notched) | 12–16 ft-lb/in (ASTM D256) |
| CTE | 3.8 × 10⁻⁵ in/in/°F (6.8 × 10⁻⁵ mm/mm/°C) |
| Max Continuous Service Temp | 125°C (257°F) |
| Flame Rating | UL94 V-2 (0.060") to V-0 (0.125") |
| Moisture Absorption | 0.15% by weight (24 hr immersion, ASTM D570) |
Machinability, Tooling & Feeds
| Process | Recommended Parameters |
|---|---|
| CNC Routing | Single/O-flute carbide, 10°–15° helix, 12k–18k RPM, 100–200 IPM (0.125"), 60–100 IPM (0.375") |
| Drilling | 118° HSS/Carbide bits, peck cycle (0.010"–0.020" per peck) |
| Sawing | Carbide-tipped blade, 60–80 teeth (10"), 0° hook, 3k–4k RPM |
| Laser Cutting | CO₂ (10.6 µm), <80% power, compressed air assist |
| Thermoforming | Pre-dry 120°C (250°F) for 2–4 hrs, form at 160°C–180°C (320°F–356°F) |
| Bonding | Methylene chloride solvents (Weld-On 3, 4, 16) or 3M DP-8005 adhesive |
| Finishing | 220–400 grit wet/dry sanding, flame polish or buffing wheel |
Common Defects & Quality Control
| Defect | Cause / Inspection Method |
|---|---|
| Surface Scratches / Abrasions | Handling on dirty tables / Inspect under raking light |
| Internal Stress Cracks (Crazing) | Aggressive machining, solvent exposure / Polarized light or solvent dip test (IPA) |
| Yellowing / Haze | UV exposure (non-UV grade) or overheating / UV meter or manufacturer label |
| Thickness Variation | Extrusion inconsistency / Micrometer measurement at 5 points per sheet |
| Warpage / Bowing | Improper storage (horizontal) or residual stress / Feeler gauge on granite plate (max 0.125" over 48") |
| Contamination / Fish Eyes | Poor extrusion quality / Visual inspection under backlight |
| Delamination (UV Layer) | Co-extrusion failure / Tape peel test (ASTM D3359) |
| Edge Cracking | Dull tooling or excessive feed / Inspect with 10x loupe |
Storage, Handling & Racking Guidelines
| Guideline | Specification / Recommendation |
|---|---|
| Orientation | Vertical in A-frame racks with ≥10° tilt from vertical |
| Max Stack Height | 20 sheets (0.125"), reduce proportionally for thicker sheets |
| Environment | 18°C–25°C (65°F–77°F), 40–60% RH. No direct UV. |
| Protective Film | Remove only immediately before fabrication. Re-cover if removed early. |
| Handling | Clean cotton or nitrile gloves. Avoid skin oils. |
| Cutting Method | Score & snap (≤0.060"), table saw with carbide blade (>0.060") |
| Inventory System | FIFO with date labels. Use Ryxen SupplyGrid for low-stock alerts (set at 2 sheets/thickness). |