PC/ABS Injection Moulding: Properties, Grades & Design Guide
PC/ABS is a polymer alloy that takes the stiffness and heat resistance of polycarbonate and combines it with the processability and surface quality of ABS. The blend outperforms both constituent resins in impact strength — particularly at low temperatures — processes more readily than pure PC, and costs less per kilogram than polycarbonate alone. It is the standard material for automotive interior trim, consumer electronics housings, and power-tool bodies.
What are the mechanical and thermal properties of PC/ABS?
The blend ratio (typically 40–70% PC by weight) determines where the material sits between the two extremes. Most commercial grades balance impact strength and heat performance against melt viscosity to remain processable on standard injection machinery.
| Property | Typical Value | Test Standard |
|---|---|---|
| Tensile Strength | 45–65 MPa | ISO 527 |
| Flexural Modulus | 2,200–2,800 MPa | ISO 178 |
| Izod Impact (notched, 23°C) | 400–700 J/m | ISO 180 |
| Izod Impact (notched, –30°C) | 200–500 J/m | ISO 180 |
| Heat Deflection Temp (0.45 MPa) | 105–125°C | ISO 75 |
| Vicat Softening Point | 115–130°C | ISO 306 |
| Density | 1.10–1.20 g/cm³ | ISO 1183 |
| Mould Shrinkage | 0.4–0.7% | ISO 294-4 |
| Water Absorption (24 h) | 0.15–0.25% | ISO 62 |
The low-temperature impact figure matters for automotive and portable electronics in cold climates. PC/ABS retains a ductile failure mode at –30°C where plain ABS transitions to brittle fracture — a real-world difference for dashboards, tool housings, and outdoor equipment enclosures.
Where is PC/ABS injection moulding used?
PC/ABS sits between commodity ABS and specialty PC in cost and performance, which makes it the practical choice for the tier of applications that need more than ABS but do not need full polycarbonate.
Automotive interior trim: Dashboard panels, centre console components, HVAC vents, A- and B-pillar covers, and interior door handles. The material's 105–125°C HDT covers the heat near ventilation outlets; the low-temperature impact retention covers cold-climate markets.
Consumer electronics and IT equipment: Laptop lids and bottom shells, tablet frames, monitor bezels, printer bodies, and power-bank housings. PC/ABS gives OEMs a route to thin-wall, high-rigidity shells that can be painted or textured at lower cost than pure PC.
Medical device housings: Diagnostic instrument casings, imaging equipment shells, and lab equipment bodies. Medical-grade PC/ABS is available with low-extractables and biocompatibility data — confirm the specific grade data sheet at DFM.
Power tools and industrial hand-held equipment: Drill bodies, angle-grinder guards, and measurement instrument housings. High impact resistance with grip-texture capability is the combination that makes PC/ABS the standard here.
Electrical and electronic enclosures: UL 94 V-0 and V-2 flame-retardant grades are widely available, allowing PC/ABS to meet IEC enclosure classifications for switchgear, junction boxes, and control panels.
What are the moulding characteristics of PC/ABS?
PC/ABS is more demanding to process than plain ABS but substantially more forgiving than pure PC. The higher viscosity and hygroscopic sensitivity require careful parameter control.
Melt temperature: 230–280°C. Higher PC-content grades require the upper end. Degradation and discolouration occur above 290°C; minimise residence time accordingly.
Mould temperature: 60–90°C. A warmer mould reduces internal stress, improves surface gloss, and decreases weld-line weakness. Parts cooled too quickly are prone to stress whitening under subsequent load.
Injection pressure: 80–160 MPa. Higher viscosity relative to ABS demands adequate fill pressure, particularly in thin-wall sections. Gate size and location are critical design choices.
Drying: 3–4 hours at 90–110°C in a dehumidifying dryer. Both constituent polymers are hygroscopic; moisture causes hydrolytic degradation, permanently reducing molecular weight and impact strength. Drying at the lower bound (90°C) is adequate for standard grades; high-PC-content or medical grades may need the upper end for 4+ hours.
Shrinkage: 0.4–0.7%. Anisotropy is low. High-PC grades sit toward the lower end of the range; high-ABS grades toward the upper.
Draft angles: Minimum 1° on unpainted surfaces; 2–3° on textured surfaces. PC/ABS has slightly higher friction against polished steel than ABS — generous draft reduces ejection force and prevents drag marks.
Sink and warp: Warp tendency is low for a PC-bearing material. Sink marks appear at rib-to-wall ratios above 60% or at bosses with wall over 60% of nominal. Gate positioning relative to heavy sections is the primary warp mitigation lever.
Which PC/ABS grades and variants should you consider?
| Grade / Variant | Key Feature | Typical Application |
|---|---|---|
| Standard PC/ABS (general purpose) | Balanced impact + processability | Electronics housings, general enclosures |
| High-impact PC/ABS | Higher rubber phase, lower HDT | Handles, portable equipment |
| High-heat PC/ABS | Higher PC ratio, HDT 120–125°C | Automotive HVAC, appliances |
| Flame-retardant PC/ABS (V-0) | Halogen-free or halogenated FR | Electrical enclosures, IT equipment |
| UV-stabilised PC/ABS | Hindered amine light stabilisers | Outdoor portable equipment |
| Medical-grade PC/ABS | Low extractables, ISO 10993 data | Diagnostic and imaging equipment |
| PC/ABS + GF (10–20%) | Glass fibre reinforced | Dimensional-critical structural parts |
Glass-filled PC/ABS (10–20% GF) substantially increases stiffness (flexural modulus up to 5,500 MPa) and reduces thermal expansion, at the cost of surface finish quality and increased tool wear.
Advantages and limitations of PC/ABS
Advantages:
- Superior impact strength to ABS, most significantly at sub-zero temperatures
- HDT 15–25°C higher than standard ABS grades
- Lower processing temperature and better flow than pure PC — reduces tooling wear and energy cost
- Low shrinkage and low warp relative to semi-crystalline materials
- Wide range of FR grades including halogen-free options
- Good paint adhesion and laser-markability without surface treatment on most grades
Limitations:
- Moderate chemical resistance — solvents, aggressive cleaners, and fuels cause stress cracking
- Hygroscopic; rigorous drying protocol required before processing
- Higher material cost than plain ABS
- Not suitable for prolonged outdoor UV exposure in standard grades
- More complex to recycle than single-polymer streams
When to choose PC/ABS over alternatives
PC/ABS vs plain ABS: Choose PC/ABS when low-temperature impact performance, HDT above 95°C, or thin-wall rigidity for large-format parts is required. Plain ABS is sufficient and cheaper for general room-temperature opaque housings.
PC/ABS vs pure PC: Use PC/ABS when optical clarity is not needed and processing cost matters. Pure PC is preferred for transparency, HDT above 130°C, or the thinnest-wall UL 94 V-0 performance.
PC/ABS vs ABS+GF: Use PC/ABS when surface finish and paintability matter. Glass-filled ABS delivers more stiffness but degrades surface quality and is harder to paint.
PC/ABS vs PPO/PPE blends (Noryl): PPO/PPE blends offer lower density and better hydrolytic stability. PC/ABS is preferred when tight dimensional tolerances, higher surface gloss, or a wider commercial grade selection is the priority.
Nordmould recommends PC/ABS as the default upgrade path from ABS when the application demands improved impact or heat performance without moving to a more specialised engineering polymer.
Is PC/ABS recyclable?
PC/ABS alloy is classified as resin code 7 (Other) and is not collected in residential streams. Industrial take-back and mechanical recycling programmes exist, particularly in automotive and IT-equipment sectors. Recycled PC/ABS retains useful mechanical properties when blended with virgin resin. Halogen-free FR grades offer a cleaner end-of-life pathway than brominated alternatives.
Frequently asked questions
What is the shrinkage rate of PC/ABS in injection moulding?
PC/ABS blends shrink 0.4–0.7%, slightly less than pure ABS and considerably less than pure PC. The blend ratio determines the exact figure; Nordmould selects the tool compensation factor based on the specific commercial grade specified for your part.
Is PC/ABS stronger than plain ABS?
Yes. PC/ABS offers noticeably higher impact strength and a higher heat deflection temperature than standard ABS, while remaining easier to process than pure PC. The improvement is most pronounced at low temperatures, where the PC phase prevents brittle fracture.
Can PC/ABS be used for automotive interior parts?
PC/ABS is one of the most widely specified materials for automotive interior trim — dashboards, A-pillar covers, HVAC bezels, and door hardware. Automotive-grade PC/ABS meets relevant heat and impact requirements. Nordmould can source heat-stabilised and UV-stabilised automotive grades.
Does PC/ABS require drying before injection moulding?
Yes. PC/ABS must be dried at 90–110°C for 3–4 hours in a dehumidifying dryer before processing. Inadequate drying causes silver streaks, splay, and degraded impact properties. High-PC-content grades may need the upper end of the temperature range and longer dwell time. Pre-drying is included as standard in Nordmould's production process.
How does PC/ABS compare to pure PC for enclosures?
PC/ABS is easier to process, warps less, and costs less per kilogram than pure PC, while still meeting most enclosure requirements. Pure PC is preferred when optical clarity, maximum heat resistance above 130°C HDT, or UL 94 V-0 at very thin walls is required.
What wall thickness is recommended for PC/ABS parts?
A wall thickness of 1.5–3.5 mm is recommended for PC/ABS. Thinner walls risk incomplete fill due to the blend's higher viscosity relative to ABS; thicker walls increase the risk of sink marks and internal voids. Nordmould reviews wall thickness during the DFM stage.
What is the minimum order quantity for PC/ABS parts at Nordmould?
Nordmould's minimum order is 100 pieces across all materials including PC/ABS. Tooling starts from €3,000; aluminium bridge tooling is available for low-to-mid volume production runs.
Is PC/ABS recyclable?
PC/ABS is technically recyclable but separation from other polymer streams is difficult. Recycled PC/ABS is used industrially. Halogen-free flame-retardant grades have better end-of-life options. Nordmould can advise on recyclable-grade availability for your specific application.
Send your STEP file to Nordmould for a free DFM review and written quote — typically returned within one business day.