The Main Differences Between ABS and PC Filaments for 3D Printing

• 1
  ABS vs PC: quick comparison
• 2
  Why ABS and PC filaments behave differently under heat
• 3
  Warping, bed adhesion and enclosure needs
• 4
  Drying ABS and PC filaments before printing
• 5
  Post-processing, tolerances and when to stop printing

ABS is a styrene-based terpolymer. Its glass transition sits near 105 °C, so a printed bracket starts to soften once it stays near that temperature. PC is a polycarbonate chain with bulky bisphenol groups, and its glass transition lands near 147 °C. That 40 °C gap decides most material choices in practice.

The gap shows up in service, not on the spool. An ABS enclosure that sits beside a 90 °C motor will creep and lose bolt preload over a few hundred hours. The same part in PC holds shape until it passes 130 °C, which is why under-hood brackets and lamp housings often move to PC.

Stiffness follows the same pattern. PC prints typically reach 55–75 MPa tensile strength against 38–50 MPa for ABS. PC is also more notch-sensitive, so a sharp internal corner that survives in ABS can crack in PC under the same load.

• 1
  Above 100 °C continuousChoose PC. ABS will creep.
• 2
  Room temperature onlyABS is cheaper and prints faster.
• 3
  Sharp internal cornersAdd a fillet or PC will crack.

Both materials shrink as they cool, and both pull off the bed if the chamber is cold. ABS shrinks roughly 0.7 percent and PC closer to 0.8 percent. On a 200 mm part that is about 1.5 mm of movement, enough to lift corners and split layers.

PC needs the hotter setup. Nozzle 270–310 °C, bed 110–130 °C, and an actively heated chamber near 60–80 °C. ABS runs at 230–250 °C nozzle and 90–110 °C bed, and a passive enclosure usually holds it. If you cannot close the machine, print neither material.

Bed adhesion is the second failure point. ABS sticks to a PEI sheet or a slurry of ABS and acetone. PC bonds best to PEI at 120 °C or to a glue stick layer that doubles as a release agent. Let both cool to room temperature before removing the part. Pulling a warm PC part off a PEI sheet tears the sheet.

• 1
  Cold chamberCorner lift and layer splits on both.
• 2
  Large flat geometrySplit the model or switch to machining.
• 3
  Removing warm partsWait for full cooldown.

ABS absorbs little moisture and often prints fine straight from a sealed bag. PC is the opposite. Polycarbonate hydrolyzes at nozzle temperature, and wet pellets break down into shorter chains. You hear it as a popping sound and see it as bubbles, a rough surface and weak layer bonds.

Dry PC for 4–6 h at 80–90 °C in a dedicated dryer, then print from a dry box. ABS needs 2–4 h at 70–80 °C only if the spool has been open in humid air for weeks. A food dehydrator works for both if it holds temperature within a few degrees.

Test before a long print. Push 100 mm of filament through a hot nozzle and watch the extrusion. Crackles mean more drying time. Silent extrusion means the spool is ready.

• 1
  PC left on the machine overnightDry it again before the next run.
• 2
  No dryer availableBuy PC in vacuum-sealed 0.5 kg spools.

ABS has one advantage PC cannot match. Acetone vapor smooths an ABS surface to a glossy finish in 20–40 minutes, and it welds layer lines together. PC resists acetone, so you are limited to sanding, tumbling or machining.

Tolerances are the harder limit. FDM holds roughly ±0.3 mm on a well-tuned machine, and warp moves critical features further. If a part needs ±0.005 mm, a Ra 0.8–1.6 μm finish or a flatness callout, no filament choice fixes it.

That is where we come in. GreatLight machines ABS and PC stock directly, along with POM, PEEK, PMMA and PA, on 127 CNC machines across three plants in Dongguan and Singapore. A printed prototype proves fit. A machined part holds the tolerance.

• 1
  Cosmetic coversPrint in ABS, smooth with acetone.
• 2
  Functional bracketsPrint for fit, then machine in PC.
• 3
  Tight toleranceSkip printing, go straight to CNC.