PC CNC Machining Service

Why Choose Polycarbonate

Unmatched Impact Resistance Among Transparent Materials

PC is virtually unbreakable in typical structural applications — it absorbs impact by deforming without shattering. Safety glazing, machine guards, riot shields, and bulletproof glass all use PC because no other transparent material approaches its impact resistance at practical thickness and cost.
Optical Clarity

PC transmits over 88% of visible light — comparable to glass. For transparent housings, sight glasses, light diffusers, and optical components where glass is too brittle or too heavy, PC is the standard choice.
Good Heat Resistance

PC maintains structural properties up to approximately 130°C continuous — significantly better than ABS (80°C) or PMMA/acrylic (70°C). For electrical enclosures near heat sources, automotive under-hood components, and medical sterilization applications, PC's thermal performance is often the deciding factor.
Dimensional Stability

PC has moderate moisture absorption (0.35%) and good dimensional stability — better than nylon, acceptable for most precision applications. It holds machined tolerances well in ambient conditions.

Common PC Grades

Standard PC

High light transmission for windows, light guides, and transparent panels. Machined to close tolerances for precise optical features.

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Our Machining Capability

PC is regularly machined in our facility for transparent windows, structural housings, and prototype enclosures. Key machining consideration: PC is prone to internal stress cracking if sharp tools, excessive heat, or aggressive cutting parameters are used — we use sharp carbide tooling, flood coolant, and conservative feed/speed parameters optimized for PC. For optical-grade transparent parts, annealing after machining is recommended to relieve residual stress before final inspection. Tolerances held to ±0.05 mm standard; ±0.02 mm on stable non-optical features.
Limitations & Cost Considerations

PC is susceptible to solvent attack — many common chemicals (acetone, MEK, strong bases, some cleaning agents) cause stress cracking or surface crazing. PC also scratches more easily than glass or PMMA — scratch-resistant coatings are available but add process steps. UV resistance is moderate — outdoor applications require UV-stabilized grades or UV-protective coating to prevent yellowing. PC is significantly more expensive to machine than ABS due to slower cutting speeds and higher tooling consumption.

FAQ

When should I use PC instead of PMMA (acrylic) for transparent parts?

Use PC when impact resistance is the priority — PC is 250× more impact-resistant than glass and significantly tougher than PMMA. Use PMMA when optical clarity and scratch resistance are the priorities — PMMA has better light transmission (92% vs. 88%), is harder (more scratch-resistant), and is cheaper. For safety glazing, machine guards, and any transparent part subject to impact, PC is correct. For display covers, decorative panels, and optics where scratch resistance matters more than impact, PMMA is the better choice.
Can PC be used for medical applications?

Medical-grade PC (ISO 10993 biocompatibility certified) is widely used for medical device housings, surgical trays, and diagnostic equipment components. Sterilization compatibility depends on the grade — standard PC withstands EtO and gamma radiation; autoclave sterilization (above 121°C) requires special high-heat grades. Confirm sterilization method and frequency before material selection.
What tolerances can you hold on PC parts?

±0.05 mm as standard. For stable features not prone to thermal or stress-induced movement, ±0.02–0.03 mm is achievable. Residual machining stress can cause dimensional drift in PC if not annealed — for precision optical or tight-tolerance PC parts, we recommend post-machining annealing (120°C, 2–4 hours) before final inspection.
Can polycarbonate be painted or bonded?

PC can be painted with PC-compatible primers and paints (solvent-based paints require careful selection to avoid stress cracking). Bonding is done with structural adhesives (avoid solvent-based adhesives which attack PC) or mechanical fasteners. PC can also be ultrasonically welded and heat-staked for assembly.
Is polycarbonate suitable for outdoor applications?

Standard PC yellows and loses impact resistance under prolonged UV exposure. For outdoor applications, specify UV-stabilized PC (e.g., UV-grade Makrolon or Lexan with co-extruded UV cap layer). UV-stabilized PC is used for skylights, bus shelters, and outdoor signage where long-term transparency and impact resistance are both required.