Material selection
ABS vs Polycarbonate (PC)
Both are common enclosure and housing plastics, both mold and machine well, and a part drawn for one will usually mold in the other without a redesign. The difference that actually decides between them is what the part has to survive after it ships: a drop, a hot environment, or the need to see through it. The short answer: polycarbonate is the stronger, more heat resistant and clear one; ABS is cheaper, easier to mold and finish, and more tolerant of solvents; PC/ABS, the blend of the two, sits between them. The numbers below are the same published datasheet values used on each material's own page, set side by side.
| ABS | Polycarbonate | |
|---|---|---|
| Density | 1.04 g/cm³ | 1.20 g/cm³ |
| Tensile strength | 40–45 MPa | 60–70 MPa |
| Flexural modulus | 2.3 GPa | 2.3 GPa |
| Heat deflection (1.8 MPa) | 88 °C | 130 °C |
| Mold shrinkage | 0.4–0.7 % | 0.5–0.7 % |
| Optical clarity | Opaque | 88 % transmission (clear) |
| Relative cost | Low | Medium |
Published values for unfilled grades at 23 °C unless stated, taken from each material's own datasheet page. Confirm against the supplier datasheet for the grade you specify.
What ABS is
ABS is a two-phase polymer: a rigid styrene-acrylonitrile matrix with butadiene rubber dispersed through it. The matrix gives stiffness and a hard surface, the rubber phase absorbs impact energy. It molds at low pressure, holds fine texture, takes paint and plating without primer, and solvent-welds cleanly with MEK or acetone. Its limits are heat and UV: it softens above roughly 90 °C and yellows outdoors without a stabilised grade.
What Polycarbonate is
Polycarbonate is the material to specify when a part has to survive being dropped, hit, or loaded near its limit without shattering. Notched Izod impact is roughly ten times that of acrylic, and it fails by yielding rather than cracking. It is optically clear, rated for continuous use around 115–125 °C, and holds tolerance across a wide temperature range. The trade-off is chemical sensitivity: many solvents, alkalis and some cleaning agents cause stress cracking, and it needs thorough drying before molding or it hydrolyses in the barrel and loses impact strength permanently.
ABS against Polycarbonate
| ABS | Polycarbonate | |
|---|---|---|
| Impact resistance | Good, absorbs energy through the rubber phase | Excellent, the highest of the common enclosure plastics, fails by yielding not cracking |
| Heat resistance | Softens above roughly 90 °C | Rated for continuous use to 115–125 °C |
| Optical clarity | Opaque only | Clear or tinted, 88 % transmission |
| Chemical resistance | Moderate, solvent-weldable | Poor, stress-cracks with many solvents and alkalis |
| Finish and paintability | Excellent, takes paint and plating without primer | Good, but more prone to stress cracking under coating solvents |
| Processing | Forgiving: melt 220–250 °C, mold 50–70 °C, dries in 2–4 hours | Demanding: melt 280–320 °C, mold 80–110 °C, needs thorough drying or it degrades |
| Relative cost | Low | Medium, typically 30–50 % more per kilo |
Which one, for which part
- Consumer enclosures and housings that need a good finish at low cost is ABS's case: it paints, plates, and textures well, and the tooling and material cost less.
- Anything that has to survive an impact, a drop, or sustained load near its limit is polycarbonate's case: safety guards, machine windows, structural prototypes that get tested rather than just inspected.
- A part that has to be seen through is polycarbonate by default among common thermoplastics; ABS is never optically clear.
- A part that runs hot, near or above 90 °C in service, needs polycarbonate's higher heat deflection; ABS will visibly deform.
- A part exposed to solvents, cleaning fluids, or alkalis favours ABS; polycarbonate is the more chemically sensitive of the two and can stress-crack in service.
ABS vs PC/ABS vs polycarbonate
Searches for "ABS polycarbonate" or "PC and ABS" often mean the blend, not the comparison. PC/ABS is a third material: polycarbonate supplies heat resistance and impact strength, ABS supplies flow and a surface that finishes well. Where a part needs ABS's finish with more toughness and heat resistance than ABS alone provides, the blend avoids forcing a choice, and it is the standard material for automotive interior trim. It does not match either parent resin on its strongest property, as the three columns show.
| ABS | PC/ABS | Polycarbonate | |
|---|---|---|---|
| What it is | Two-phase polymer, SAN matrix with butadiene rubber | A blend of the two resins, not a copolymer, ratio adjustable | Straight polycarbonate, no blend |
| Density | 1.04 g/cm³ | 1.13 g/cm³ | 1.20 g/cm³ |
| Tensile strength | 40 to 45 MPa | 55 MPa | 60 to 70 MPa |
| Heat deflection (1.8 MPa) | 88 °C | 100 to 115 °C | 130 °C |
| Optical clarity | Opaque | Opaque, no transparent grade | 88 % transmission (clear) |
| Chemical resistance | Moderate, solvent-weldable | Closer to PC than ABS | Poor, stress-cracks with many solvents |
| Drying before molding | 2 to 4 hours at 80 °C | 3 to 4 hours at 90 to 100 °C | About 4 hours at 120 °C, not optional |
| Melt and mold temperature | 220 to 250 °C, mold 50 to 70 °C | 250 to 280 °C, mold 60 to 90 °C | 280 to 320 °C, mold 80 to 110 °C |
| Typical wall | 1.5 to 3.0 mm | 1.5 to 3.0 mm | 2.0 to 3.5 mm for structural parts |
| Relative cost | Low | Medium | Medium |
Values for unfilled grades, taken from the ABS, PC/ABS and polycarbonate material pages. Confirm against the supplier datasheet for the grade you specify.
- Choose PC/ABS over ABS when a housing has to pass a drop test or run warmer than ABS tolerates but still needs a molded, paintable cosmetic surface.
- Choose PC/ABS over polycarbonate when the part does not need to be clear and thinner walls or longer flow lengths matter: it fills far more easily than straight PC.
- Do not choose PC/ABS for chemical resistance. It behaves closer to polycarbonate than ABS, so check cleaning agents before committing.
For the blend against straight polycarbonate spec by spec, see polycarbonate vs PC/ABS.
Our status
Trumould molds both ABS and polycarbonate in-house across a 25 to 3,000 ton press range, and both also run through our CNC machining and 3D printing capabilities for prototypes and low volumes. Send the part, its service environment, and target volume, and the quote states which resin is recommended and why, not just a price for whichever one you asked about first.
Specifying this part?
Send your CAD and target volumes. We come back with a price, a lead time, and any material or design notes that would reduce either.