Polycarbonate and PCTG

TL;DR

Choose PC when you need the highest heat resistance and stiffness—and you can manage warping with a hot bed, draft control/enclosure, and a locked-in first layer. Choose PCTG when you want tough, durable parts with PETG-like print behavior; keep it dry and tune temperature/retraction to control stringing.

Where each material shines

Polycarbonate (PC) is a stiff engineering plastic that keeps its shape better in heat than most common FDM filaments. You pick it for brackets, fixtures, and parts that must stay rigid in warm environments—but it asks a lot from your printer setup. PCTG is a copolyester in the PETG family. You pick it for durable, impact-tough functional parts with less brittleness than PLA, and it usually prints with fewer warping headaches than PC while still improving temperature performance over PLA/PETG in many use cases.

PC vs PCTG at a glance

Heat resistance

PC is usually higher. PCTG is moderate-to-high and is often sufficient for warm environments like enclosures, car interiors, and tool parts (depending on the filament).

Print difficulty

PC is demanding: warping, bed-adhesion trouble, and layer splitting are common without stable heat and draft control. PCTG is more forgiving and behaves closer to PETG.

Warping tendency

PC: high, especially on large, flat parts. PCTG: medium; it can still lift on big plates or in cool rooms.

Layer bonding

Both can bond well when you print hot enough and avoid drafts. PC is more sensitive to uneven cooling and needs a steadier thermal environment.

Best reason to choose

PC: maximum temperature capability and stiffness. PCTG: tough functional parts with easier printing and lower crack/warp risk.

Before you buy a spool (capability checks)

• Hotend temperature headroom: verify your printer can reach and hold the filament’s stated range for that exact PC/PCTG
• Bed temperature consistency: plan for a reliably hot bed—swings show up as corner lift and a patchy first layer
• Draft control plan: expect an enclosure or serious draft shielding for PC; for PCTG it’s optional on small parts but helpful on larger ones
• Drying and storage workflow: assume you’ll need drying and sealed storage—moisture drives stringing and can weaken parts
• Build surface and release strategy: follow the maker’s recommendation and use a release layer if the surface can grip too aggressively

What you’re really controlling

With PC, most failures come from thermal stress. The part shrinks as it cools, and uneven cooling pulls corners up or splits layers. Your priorities are a stable, warm, draft-free environment and a first layer that stays anchored. With PCTG, the big enemy is messy extrusion: wet filament or too much heat can cause stringing and blobs. Your priorities are dry filament, sensible nozzle temperature, and just enough cooling to keep details crisp without triggering lift on larger parts.

Quick proof tests before a long functional print

1. First-layer strip: print a wide single-layer patch; you want even squish and clean release after cooling (not torn surface damage)
2. Warp coupon: print a thin rectangle with sharp corners; if it lifts, improve draft control, add a brim, and recheck bed temp and first-layer Z offset
3. Layer-bond temperature tower: test a few nozzle temps and pick the lowest temp that still bonds strongly (critical for PC)
4. Detail sample (holes/overhangs): confirm cooling needs—PCTG may need more cooling for sharp detail; PC often needs less cooling and a steadier enclosure; if PCTG looks fuzzy/stringy, suspect moisture or too much heat first

Common failures and first fixes