ABS vs. polycarbonate (PC): side-by-side data, uses and what changes when you switch

ABS vs. polycarbonate side by side: strength, impact and heat

General-purpose, unfilled grades, dry as molded. The first ASTM values match our ABS properties and polycarbonate properties pages. The ISO rows come from individual producer data sheets, so they show where typical grades sit, not limits. ASTM D256 results in J/m and ISO 180 results in kJ/m² are different tests and do not convert into each other (see Izod vs. Charpy impact). For the wider three-way picture with nylon, see ABS vs. PC vs. nylon.

ISO rows: INEOS Styrolution (formerly BASF) Terluran GP-22 for ABS; Covestro Makrolon 2407 and SABIC LEXAN 141R for PC; a second ABS ISO 180 value from a distributor listing of Trinseo MAGNUM 3325 MT. Heat-resistant ABS values match our ABS grade finder. Grades vary, so confirm on the data sheet for the grade you run. ASTM D256 uses a 3.2 mm (1/8 in) bar; ISO 180 data sheets use a 4 mm bar or, for many PC grades, a 3 mm bar, so check the footnote; see how to read a resin data sheet.

Clarity, UV, chemicals and processing compared

Starting points that match our processing chart and drying guide. Chemical ratings match our chemical-resistant plastics chart. Test with the exact chemical, concentration, temperature and strain on your part.

What the numbers mean in a real part

• PC is far tougher at room temperature, but the gap narrows in the cold. In ISO 180 notched Izod, the PC grades we read drop from about 65–70 kJ/m² with a partial, ductile break at 23°C / 73°F to about 12 kJ/m² with a complete break at −30°C / −22°F. General-purpose ABS drops from about 17–26 to about 8–10 kJ/m². Unnotched PC bars still do not break at −30°C / −22°F, and one grade absorbs about 65 J (48 ft·lb) in a puncture test (ISO 6603-2) at that temperature, so sharp notches are what make cold PC brittle. For parts used in the cold, ask for impact at your lowest temperature, or look at low-temperature PC grades or PC/ABS. See plastics for cold temperatures.
• Thick walls and sharp corners hurt PC most. The high Izod values come from 3.2 mm (1/8 in) bars. Thicker sections, sharp inside corners and molded-in stress can make PC break in a brittle way. Add radii when you move a part to PC.
• PC does not make a part stiffer. The flexural modulus of both is about 2.0–2.6 GPa. A part that bends too much in ABS bends about the same in PC. For stiffness, look at glass-filled grades; see glass-filled plastics.
• PC stretches further before it yields. Yield strain is about 6% for PC against about 2.6% for the ABS grade we read. Snap fits sized for PC can crack in ABS; snap fits sized for ABS usually work in PC. See plastics for snap fits.
• Heat: PC holds about 30–45°C / 54–81°F more under load. At 1.8 MPa (264 psi), ABS deflects at about 80–100°C / 176–212°F and PC at about 124–132°C / 255–270°F. PC softens near its glass transition, about 143°C / 289°F on one Covestro sheet. Long-term use temperatures are lower than HDT; check the UL relative thermal index (RTI) for the grade and see HDT vs. continuous use temperature.
• Weight. PC is about 12–17% denser, so the same part weighs more and uses more pounds of resin per part.
• Scratches. Neither is scratch resistant. Ball indentation hardness is about the same on the sheets we read (about 97 MPa for ABS and about 95–116 MPa for PC), so the common claim that ABS resists scratches better is not borne out by data sheet hardness. Clear PC shows scratches more because you look through it. Hard coats are the usual fix; acrylic is harder but far less tough (see PC vs. acrylic).
• Flame. Standard ABS is usually HB. Many standard PC grades reach V-2 at thin walls, and flame-retardant PC grades often reach V-0 at thinner walls than FR ABS. Every rating is tied to grade, color and thickness; see UL 94 explained.

Choose ABS when, choose polycarbonate when

Choose ABS when

• The part is opaque, indoors and below about 80°C / 176°F under load.
• Cosmetics sell it: high gloss, texture, paint or chrome plating.
• Cost per part matters and room-temperature toughness of about 150–400 J/m is enough.
• You want the widest process window, lower melt and mold temperatures and easy regrind use.
• The part touches bases or mild alkaline cleaners, which attack PC.

Choose polycarbonate when

• The part must be clear or carry light: lenses, guards, covers, sight glasses.
• It must survive hard impact at room temperature, or heat of about 100–125°C / 212–257°F under load.
• It needs a flame rating at thin walls.
• You can dry to 0.02% or less and heat the mold to about 80–120°C / 176–248°F.
• You have checked every chemical, cleaner and adhesive it will touch.

Typical first choices. The final pick depends on the grade, wall thickness, temperatures and chemicals of your part.

When PC/ABS is the answer

PC/ABS is a blend of the two. It is opaque, flows and molds more easily than PC, is less notch-sensitive in thick walls, and is tougher and more heat resistant than ABS. Typical values are about 400–700 J/m notched Izod and 85–110°C / 185–230°F heat deflection at 1.8 MPa, rising with PC content (see PC/ABS properties). Many housings that once ran in PC now run in PC/ABS. See PC vs. PC/ABS and PC/ABS grades.

• ABS is not tough or hot enough, but the part is opaque. PC/ABS is the usual next step before straight PC.
• You need a halogen-free V-0 at thin walls. Halogen-free V-0 is easier to get in PC/ABS than in ABS.
• PC is hard to fill or cracks at thick sections. PC/ABS runs cooler, about 240–280°C / 464–536°F, and is less notch-sensitive.
• The part must be plated or painted with more heat than ABS takes. PC/ABS plating grades exist.
• Not when it must be clear. The blend is opaque. Use PC or acrylic.
• Not a fix for chemicals. PC/ABS still stress-cracks in many solvents, cleaners and oils. Test with the real chemicals.

ABS vs. PC filament for 3D printing

The same trade-off holds for FDM filament: ABS is the easier technical filament, PC the tougher and hotter one that is harder to print. Settings below are one printer maker's published starting points (Prusa Research); filament brands publish their own. Many filaments sold as PC are modified PC or PC blends made easier to print, so a spool's data does not describe molded PC. Filament makers buying pellets should see 3D-printing filament resin.

Starting points only, from Prusa Research's material guide. Printed parts are weaker across layers than molded parts, so data sheet values for molding resin overstate printed strength.

Machining, bonding and finishing

• Both machine well with sharp tools, light cuts and good chip clearing. Heat is the main enemy: ABS softens sooner (Vicat about 96°C / 205°F), and PC is tougher and stringier and leaves burrs.
• Coolant. Use air or plain water. Avoid cutting fluids that contain solvents, and keep alkaline or amine-based fluids off PC, since bases and amines attack it.
• Machined PC can crack later. Machining adds surface stress. If a machined PC part will meet cleaners or solvents, ask the stock or resin producer about annealing.
• Solvent bonding. ABS solvent-welds readily with ABS cements. Solvent cements also bond PC, but the same solvents craze stressed PC, so keep joints unstressed and test. Test adhesives and primers on PC for the same reason.
• Plating and paint. ABS is the standard plating resin. PC paints well, but paint solvents can stress-crack molded-in stress; use a paint system approved for PC.
• Acetone. It dissolves ABS (useful for smoothing and gluing) and crazes and cracks PC. Never wipe either with acetone in service.

Switching a tool between ABS and PC, and the common mistakes

ABS and PC shrink about the same, about 0.4–0.7% for ABS and 0.5–0.7% for PC on producer sheets, so one tool can often run both. The press and the mold setup change more than the steel. See running a different resin in your mold.

• Mold heat. PC wants about 80–120°C / 176–248°F, which usually means pressurized water or oil units and hoses rated for it. Many ABS tools run cooler.
• Barrel and hot runner. Check that heaters, nozzle and hot-runner manifold hold 280–320°C / 536–608°F for PC. Going the other way, flame-retardant ABS must stay at or below 246°C / 475°F.
• Gates and vents. PC flows stiffer. Gates sized for ABS can short-shot or freeze off and leave stress. One PC sheet gives vent depths of about 0.025–0.075 mm (0.001–0.003 in).
• Corners and snap fits. Add radii for PC. Moving from PC to ABS, check snap fits against the lower yield strain of ABS.
• Purging. ABS left in the barrel at PC temperatures degrades and leaves black specks. Purge across the change with a purging compound or a resin stable at both temperature ranges. See purging and color change.
• Shot weight and regrind. PC parts weigh about 12–17% more. Regrind limits differ; see regrind limits by resin.
• Requalify. Flame ratings, agency listings and customer approvals belong to the exact grade. Run first-article dimensions, drop tests and chemical tests again.

• Comparing ISO and ASTM numbers. An ABS sheet in J/m (ASTM D256) and a PC sheet in kJ/m² (ISO 180) cannot be compared. Ask both suppliers for the same method.
• Expecting PC to stay tough in the cold with sharp notches. Notched PC grades we read break completely at −30°C / −22°F. Test at your lowest temperature.
• Switching to PC to fix a part that bends. Stiffness barely changes. Add ribs or use a glass-filled grade.
• Keeping the same cleaner, grease or adhesive after moving from ABS to PC. Alkaline cleaners, amines and many solvents crack PC. See environmental stress cracking.
• Comparing HDT at different loads or annealing. HDT at 0.45 MPa (66 psi) runs well above HDT at 1.8 MPa (264 psi), and annealed ABS bars test higher. Compare like with like.
• Assuming "UV stabilized" means weatherproof. Stabilizers slow yellowing in PC; they do not stop it. ABS needs ASA, a cap layer or paint outdoors.

Cost, supply and what to put on the RFQ

PC usually costs more per pound than ABS, with PC/ABS in between. Because PC is about 12–17% denser, a PC part also uses more pounds of resin, so the cost gap per part is wider than the gap per pound. ABS follows styrene, acrylonitrile and butadiene, and much of the ABS used in North America is imported. PC follows bisphenol A and its feedstocks, phenol and acetone. Optical, flame-retardant, medical and low-temperature PC grades, and plating, high-heat and flame-retardant ABS, carry premiums over general purpose and can have longer lead times. See how resin is priced and price and lead-time problems.

We do not post prices. We quote a specific grade, color, quantity, package and ship-to city through our supply partners, from one gaylord (about 1,000 to 1,600 lb) up, and every prime lot from our suppliers ships with a COA. Send these with the request:

• The grade you run now, or the data sheet, and whether the part could move to the other resin or to PC/ABS.
• Impact at room temperature and at your coldest use temperature, by a stated method (ASTM D256 or ISO 180).
• Heat: HDT at a stated load (0.45 or 1.8 MPa), and whether annealed.
• Flame: UL 94 rating, thickness and color, and halogen-free if required.
• Clarity: light transmission and haze at your wall thickness, for clear PC.
• Outdoor and chemical exposure: UV, cleaners, oils and adhesives the part meets.
• Quantity, package and ship-to. Gaylord, truckload, yearly use and city. See send an RFQ package.

Common questions

If your grade is not listed, tell us what you run. We source commodity, engineering and specialty resins.