PC (polycarbonate) is the highest impact resistance material available in consumer FDM printing. It’s the plastic used in safety helmets and bulletproof glazing — the same impact-absorbing properties transfer to printed parts. It also handles sustained temperatures up to 130–140°C, which nothing else in this range can match. The cost: it requires higher temperatures than most hotends can reach, warps severely, and absorbs moisture rapidly.
Where PC Is Actually the Right Choice
Functional parts that must survive violent impact without cracking: protective enclosures, mechanical guards, load-bearing brackets under shock load. High-heat applications where ABS or ASA would soften: engine bay components, lighting fixtures, parts near heat sources above 100°C. Parts requiring both heat resistance and clarity — PC is naturally transparent.
If your part doesn’t need impact resistance significantly above ABS level or heat resistance above 100°C, use ASA or ABS instead. PC’s print difficulty isn’t worth it for parts where those materials are adequate.
Hotend Requirements
PC prints at 260–300°C. Most all-metal hotends handle this. PTFE-lined hotends should not be used above 240°C — PTFE degrades at 260°C+ and off-gasses toxic fumes. Confirm your hotend is all-metal before printing PC. Nozzle material doesn’t matter much — PC is not abrasive, so brass works fine.
Temperature
Nozzle: 270–280°C is the typical working range. At 260°C, you’ll see delamination cracking; at 280°C, most PC prints with adequate layer adhesion. Some engineering-grade PC blends need 290–300°C.
Bed: 110–120°C. PEI at 110°C gives good adhesion. PC needs a large-format brim (10mm) on any part with corners — the shrinkage stress is high and corners lift off even well-heated beds. After the print finishes, wait for the bed to cool below 50°C before removing — PC bonds strongly when hot.
Enclosure
Mandatory. PC has one of the highest coefficients of thermal expansion of any printable material. Without an enclosure holding 50–60°C chamber temperature, any print taller than 30–40mm will crack and delaminate. This is not a setting problem — it’s thermal physics. A heated chamber is the only solution.
Moisture
PC absorbs moisture significantly within hours of exposure. Moisture causes hydrolysis (the polymer chains break down), which reduces both impact resistance and layer adhesion — properties that PC is specifically chosen for. Dry at 80°C for 4–8 hours before printing. Print within a few hours of drying, or use a dry box.
Fan
Zero fan. PC requires every joule of heat retention for inter-layer bonding. Cooling fan produces delamination immediately. Bridges over 30mm may need 10–15% fan; accept worse bridge quality rather than risking delamination on the wall sections.
Adhesion Aids
PC adheres to PEI at 110°C, but the bonding can be excessive. A thin layer of PVA glue stick prevents the part from fusing to the surface on large flat-bottom parts. PC on bare glass without any adhesive has poor adhesion.
What PC Blends Trade Off
PC+ABS blends (PC-ABS) are easier to print than pure PC — slightly lower temperatures, less warping, still excellent impact and heat resistance. They’re a good middle ground when pure PC print conditions are too demanding. PC-CF adds stiffness but reduces impact resistance somewhat. Pure PC maximizes both impact resistance and heat resistance.