Polycarbonate (PC), often known by trade names like Lexan or Makrolon, is a naturally transparent amorphous thermoplastic known for its incredibly high impact resistance and toughness. It is virtually unbreakable, making it the ideal material for safety shields, optical lenses, and robust electronic housings. However, machining PC to optical clarity requires expertise. At Jucheng Precision, we specialize in producing optically clear Polycarbonate parts. We combine precision CNC milling with secondary processes like Vapor Polishing and hand buffing to remove tool marks and restore transparency. Our ISO 13485 certified facility ensures that even complex medical manifolds or automotive lighting prototypes are produced with strict adherence to dimensional tolerances (+/- 0.02mm) and cosmetic standards.
Specially annealed to remove internal stresses, Machine Grade PC ensures superior dimensional stability during and after CNC machining. It allows for tight tolerances without the risk of warping or cracking. It is the ideal choice for manufacturing complex structural housings, manifolds, and semiconductor components requiring high precision.
Engineered for maximum light transmission and minimal haze, Optical Grade PC provides glass-like clarity combined with high impact resistance. It is optimized for vapor polishing to achieve mirror-like surface finishes. This grade is perfect for automotive lenses, light guides, and medical sight glasses where visibility is critical.
Reinforced with 30% glass fibers, PC GF30 offers exceptional rigidity and dimensional stability compared to unfilled grades. The reinforcement significantly increases tensile strength and heat resistance while drastically reducing thermal expansion. It is the premier choice for high-load industrial brackets and structural electronic frames requiring maximum stiffness.
| Grade | Common Name | Key Characteristics | Typical Applications |
|---|---|---|---|
| Standard PC | General Purpose (GP) | High impact strength, good heat resistance, and transparency. The most common grade for machining. | Machine guards, transparent manifolds, structural housings, electrical connectors. |
| Optical Grade PC | Lexan® / Makrolon® | Formulated for low haze and high light transmission. Optimized for polishing. | Lenses, light pipes, windows, display screens, automotive lighting. |
| Glass-Filled PC | GF10 / GF20 / GF30 | Reinforced with glass fibers (10-30%). Significantly increased stiffness and tensile strength, but opaque. | Structural components, rigid housings, industrial brackets. |
| Machine Grade PC | Stress-Relieved | Processed to reduce internal stress, making it easier to machine without cracking. | Precision prototypes, tight-tolerance insulators. |
| Capability | Technical Description | Jucheng Advantage |
|---|---|---|
| Vapor Polishing | Exposing machined PC parts to chemical vapor to melt the surface microscopic layer, creating an optically clear finish. | We can turn a translucent machined part into a glass-like clear component for internal verification. |
| Stress-Free Machining | PC is prone to “crazing” (micro-cracking). We use sharp tools and annealing cycles to manage stress. | Ensures durability and chemical resistance of the final part, preventing failure in service. |
| Complex 5-Axis Milling | Machining complex automotive light guides and headlight bezels with organic curves. | Our 5-axis machines allow for continuous contouring required for optical surfaces. |
| High-Speed Drilling | Drilling precise hole patterns without melting or cracking the material. | Optimized peck cycles and coolant prevent heat buildup, crucial for deep holes in PC. |
Coolant Sensitivity:
Polycarbonate is highly sensitive to chemical attack. Standard cutting fluids can cause immediate stress cracking. We use strictly compatible, non-aromatic water-soluble coolants or air blast.
Polishing Strategy:
To achieve optical clarity, the part must first be machined with a very fine step-over to minimize tool marks, followed by sanding (up to 2000 grit) and final vapor polishing or buffing.
Annealing:
Machining induces stress. For parts with tight tolerances or those requiring heavy solvent bonding/polishing, we anneal the parts in an oven to relieve internal stresses.
Tooling:
We use extremely sharp, uncoated carbide tools with high clearance angles. Coated tools can sometimes be too dull for plastic, causing heat friction that melts the PC.
Automotive
Key Parts: Headlight lenses, interior light pipes, dashboard instrument panels.
Why PC: Combines optical clarity with high impact resistance to withstand road debris.
Medical Devices (ISO 13485)
Key Parts: Blood oxygenators, surgical reservoirs, manifolds.
Why PC: Clear visibility of fluids, biocompatible grades available, and withstands sterilization (Gamma/EtO).
Safety & Security
Key Parts: Blast shields, riot gear visors, machine guards.
Why PC: Its legendary impact toughness (bullet-resistant in thick sections) protects personnel.
Electronics
Key Parts: LED covers, robust handheld device housings, battery cases.
Why PC: Flame retardance (UL94 V-0 grades) and durability against drops.
| Density | 1.20 - 1.22 g/cm³ |
| Tensile Strength | 55 - 75 MPa |
| Impact Strength | 600 - 900 J/m |
| Heat Deflection Temp | 130 - 145 °C |
| Hardness | 70 - 85 Rockwell M |
| Continuous Service Temp | 115 - 130 °C |
| Water Absorption | 0.15 - 0.35 % |
| Dielectric Strength | 15 - 17 kV/mm |
| Light Transmission | 88 - 90% |
| Max. Part Size | 2000 mm (L) x 800 mm (W) x 600 mm (H) |
