Polycarbonate is the material people move to when ABS is not enough, and the honest first question is whether ABS was actually not enough. PC is harder to print than anything else discussed on this site outside the nylons, and a large fraction of the parts printed in it would have been fine one step down.
So: name the temperature the part has to survive, and let that decide.
The band each one covers
ABS holds shape from 88 to 100 °C. Polycarbonate holds from 110 to 140 °C. Between those two lies the entire justification for the extra difficulty.
Sort your requirement into one of three:
- Under about 85 °C — ABS covers it, and so may PETG. Nothing above is needed.
- 90 to 105 °C — ABS is at its limit and the PC-ABS blend is the sensible answer, which we get to below.
- Above 110 °C — genuine polycarbonate territory, along with filled nylons and PPA.
The middle band is where most disappointment lives, because people jump straight to PC and then fight it.
What PC charges for that heat
A hotend that reaches 270–310 °C. Many machines stop at 260 or 300, and the top of PC's range is where layer bonding on a large part actually lives. Check the number before buying the spool.
A bed at 100–120 °C and a real chamber. ABS asks for 90–110 and a passive enclosure. PC asks for more of both, and it is unforgiving about it.
The worst corner lift of any common filament. The stored note is blunt about why: PC shrinks 0.5 to 0.8%, which is in ABS's territory, but it is also far stiffer, so the contraction generates much more force before anything yields. A warping ABS part curls; a warping PC part levers itself off the plate.
Drying at 90 °C for 6 to 12 hours, non-negotiable. Wet PC hydrolyses in the melt and comes out cloudy and weak — a strength loss that survives drying afterwards, as what moisture does to filament explains.
Money. $40–80 per kilogram against ABS's $18–30.
And the same part is heavier in it
Density adds a quieter cost that price-per-kilogram comparisons miss. ABS sits at 1.04 g/cm³ and PC at 1.20, so a kilogram of 1.75 mm filament runs 399.76 m in ABS and 346.46 m in PC — 53.3 m less, because PC's 15.385% higher density costs 13.333% of the length. Put your own two densities side by side with the length and weight converter.
Turned around: the same model printed in PC weighs about a sixth more than in ABS, so the material cost per part is roughly a sixth worse than the shelf price difference already suggests. On a large housing that compounds into real money.
What PC gives back beyond heat
Two things worth naming, because heat resistance alone rarely justifies the trouble.
Impact resistance with stiffness. PC's 60 to 70 MPa tensile is well above ABS's 30 to 45, and unlike most stiff materials it is not brittle. It is the plastic used for machine guards and safety glazing for exactly this combination.
Optical clarity. Printed PC is not glass-clear, but it is the only common filament here that can produce a usefully translucent structural part. ABS cannot.
Where ABS wins on merit
Vapour smoothing. Acetone works on ABS and does nothing useful to PC. If the part is cosmetic and complex, that capability is decisive on its own.
Forgiveness. ABS at difficulty 4 is hard; PC at 5 is harder, and the gap is most of an evening on any part with a large flat base.
Cheap iteration. At a third of the price and with a wider process window, ABS is what you prototype in even when the final part will be PC.
Ordinary hotends. ABS runs at 230–260 °C, comfortably inside what almost every enclosed machine can do.
The blend that solves the middle band
PC-ABS deserves more attention than it gets. It holds 95 to 120 °C — above ABS, below PC — at 250–280 °C nozzle temperatures that far more machines can reach, and its stored shrinkage of 0.4 to 0.7% is lower than pure PC's, which is precisely the practical reason to choose it.
If your requirement is "hotter than ABS manages" rather than "genuinely above 110 °C", the blend is very often what you should be buying, and it gets overlooked simply because neither of its parents' reputations attach to it. It costs $40–75, so the saving is not in the filament — it is in the parts that finish.
Choosing, honestly
Take the hottest temperature the part will see in service, add a margin for it being loaded at the time, and compare that to the two bands at the top of this page.
If the answer lands in ABS's range, print ABS and spend the difference on an enclosure that works properly. If it lands above PC's, neither of these is your material and you are looking at PPA or a filled nylon. And if it lands in between — which it does more often than people expect — reach for the blend before the pure polymer.
Whichever you choose, the enclosure question comes first: what an enclosure actually changes applies to both of these materials before any of their differences do.