Printing Polycarbonate (PC): Temperatures, Chamber and Warping
are explained briefly when you hover over or tap them.
You know polycarbonate, PC for short, from safety glasses, light covers or housings of power tools. In 3D printing it is the material of choice when a part has to withstand heat and impacts. For that it needs very high temperatures and a warm environment, otherwise it warps badly.
Settings at a glance
| Setting | Guide value |
|---|---|
| Nozzle temperature | 250 to 290 °C |
| Bed temperature | 90 to 120 °C |
| Part cooling | off or low, about 0 to 30 % |
| Chamber | enclosed, ideally actively heated |
| Build plate | textured PEI or special plate, with glue stick |
| Drying | 75 to 80 °C, 6 to 8 hours |
The values on the spool take priority. For its PC Blend, for example, Prusa gives a nozzle of 275 °C and a bed of 110 to 115 °C, while other manufacturers are at 250 to 270 °C.
What PC can do
- Heat-resistant: Depending on the grade, the heat deflection temperature is around 105 to 115 °C, so above ABS and ASA. PC is therefore suitable, for example, for fan ducts on the printer or brackets that get warm in the sun in a car.
- Impact-resistant and tough: PC does not break as easily as PLA, but tends to deform.
- Transparent grades: Clear PC can be printed, but because of the layers it never becomes crystal clear.
The flip side: PC is one of the most difficult common filaments. It is not suitable for getting started.
High temperatures: what your printer needs to manage
With 250 to 290 °C at the nozzle and over 100 °C at the bed, PC pushes many machines to their limits. Check beforehand:
- Hotend: continuously at least 270 °C, better 300 °C. A hotend with a PTFE tube all the way into the heating zone is unsuitable.
- Heated bed: must reliably hold 100 °C or more.
- Enclosure: closed, otherwise warping is almost certain for anything except small parts.
Chamber and warping
PC shrinks strongly as it cools and, like nylon, is prone to significant warping. Prusa even writes that PC warps heavily despite additives and strongly recommends an enclosure.
What helps:
- Warm chamber: An enclosed printer is the minimum. With an actively heated chamber, larger parts also succeed much more reliably. You will find an overview under Printers with a heated chamber.
- Low fan: Reduce part cooling to 0 to 30 %, slightly more only for overhangs.
- Brim: 5 to 10 mm wide.
- Design: Rounded corners warp less than sharp ones. Avoid large, flat parts across the whole bed where possible.
- No draughts: Windows shut, printer not next to ventilation or air conditioning.
Some manufacturers recommend annealing the finished part, about 2 hours at 90 °C. This relieves internal stresses.
Build plate and adhesion
PC adheres very strongly to smooth PEI and can damage the surface when removed. Prusa therefore advises against smooth PEI plates. Better:
- textured PEI plate or a plate for engineering materials
- thin layer of glue stick as a release layer, which also protects the plate
- let the plate cool down completely before removing the part
Moisture
PC is hygroscopic, though less extremely so than nylon. Damp PC shows bubbles, crackling and poor layer adhesion. Dry it before printing; a typical manufacturer figure is 75 to 80 °C for 6 to 8 hours. How best to do this is explained under Drying filament.
PC blends: easier to print
Pure PC is difficult. That is why there are blends that keep some of the properties and print more forgivingly:
| Blend | What changes |
|---|---|
| PC-ABS | Slightly lower temperatures, less warping, lower heat resistance than pure PC |
| PC-PBT | Better chemical resistance (oils, greases, weak acids), impact-resistant even in the cold, heat deflection temperature around 90 °C |
| “PC Blend” from individual manufacturers | Formulation mostly not disclosed, prints more easily, still warps on large parts |
If you are trying PC for the first time, a blend is the more sensible start. If you only need a little more heat resistance than PLA and not a high-performance part, ASA or ABS is often enough.
Typical problems
| Problem | Common cause | Solution |
|---|---|---|
| Corners lift | Chamber too cold, fan on | Preheat the chamber, fan off, brim |
| Cracks between layers | Temperature gradient in the build volume | Print enclosed, check the nozzle temperature |
| Part sticks too firmly | Smooth PEI without a release layer | Glue stick, let it cool down |
| Bubbles, crackling | Damp filament | Dry it |
| Under-extrusion | Hotend too cold or heated too slowly | Raise the temperature, lower the speed |
Continue with: Printing nylon (PA) or the filament overview.