Converters and modification engineers on the production floor know that material selection between ABS and Polycarbonate (PC) directly affects processing stability, defect rates, and daily output. Both materials rank as common amorphous thermoplastics, yet PC requires noticeably tighter process control because of its elevated melt viscosity together with pronounced sensitivity to temperature and moisture. Practical mastery of these distinctions supports consistent quality while cutting scrap.If you are still finalizing your material specification before setting up the production line, review our comprehensive guide on ABS vs PC: Which One Should You Choose for Your Product? to align polymer properties with your product requirements.
ABS
Forgiving • Shear-thinning
- Strong shear-thinning behavior
- Moderate processing temperatures
- Wider operating window
Polycarbonate
High viscosity • Moisture sensitive
- Higher melt viscosity
- Tight temperature control needed
- Critical drying required
Key Injection Molding Parameters
Successful runs rest on accurate temperature profiles. The table below outlines typical ranges; always cross-check against the specific grade and supplier datasheet.
| Parameter | ABS | PC | Notes |
|---|---|---|---|
| Barrel/Melt Temperature | 200–240°C (melt ~220–260°C) | 260–310°C (often 280–320°C) | PC needs higher heat for flow yet risks degradation during extended residence |
| Mold Temperature | 40–80°C (typical 50–70°C) | 80–120°C | Elevated PC mold temperature lowers internal stress and cracking risk |
| Drying Temperature/Time | 80°C / 2–4 hours | 120°C / 3–4 hours | Dew point < -40°C essential for PC |
| Typical Shrinkage | 0.4–0.7% | 0.5–0.7% (more uniform) | Confirm through prototype molding |
| Moisture Target | < 0.1–0.2% | ≤ 0.02% | PC highly prone to hydrolysis |
Need help optimizing your ABS or PC molding process?
Our team can review your current parameters, recommend grade-specific settings, and audit your drying & mold design for maximum efficiency.
Get Expert Process SupportRheological Behavior
ABS functions effectively as a non-Newtonian fluid showing strong shear-thinning characteristics. Viscosity drops sharply under the high shear rates of injection molding. This behavior enables reliable filling of thin walls and complex features at moderate temperatures, resulting in relatively forgiving operating windows.
PC presents higher baseline melt viscosity along with greater dependence on temperature. Minor shifts in barrel settings easily produce short shots on the low side or signs of thermal degradation—including yellowing and molecular weight reduction—on the high side.
Shear-thinning ABS vs Temperature-sensitive PC
Recommended Drying Practices
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1Temperature & Time80°C for 2–4 hours
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2Target Moisture< 0.1–0.2%
The resin absorbs moisture yet remains comparatively tolerant.
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1Temperature & Time120°C for 3–4 hours (or longer)
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2Dew Point< -40°C
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3Target Moisture≤ 0.02%
PC readily undergoes hydrolysis. Use moisture analyzers for verification.
Mold Design Requirements
Shrinkage values overlap substantially—ABS at 0.4–0.7% and PC at 0.5–0.7%. PC nevertheless displays more uniform shrinkage typical of amorphous resins. Actual values vary with mold temperature, packing pressure, and geometry, so prototype tooling remains the best validation method.
Gates & Runners
Larger gates and runners for PC to reduce shear heating. Fan gates preferred.
Venting
Deep vents (0.03–0.08 mm) at last-to-fill locations critical for PC.
Geometry Tips
Generous drafts, radiused corners, and uniform walls — especially important for notch-sensitive PC.
Proper radius design is particularly critical for PC components used in demanding environments—such as hospital disinfection cycles—where sharp corners accelerate environmental stress cracking (ESC). Learn more about this in ABS vs PC: Material Selection for Electronics, Automotive, and Medical Devices.
Practical Guidance for Production
Processors achieve best results by beginning with supplier baseline settings, then documenting and refining variables such as actual moisture content, melt temperature from air shots, and finished part quality. PC processing rewards solid drying equipment, accurate temperature management, and thorough venting. ABS provides simpler startups and broader windows, suiting cost-driven, high-volume programs.
Elevated mold temperatures for PC play a decisive role in minimizing internal stress and cracking risk. Read more in ABS vs PC Mechanical & Thermal Properties to understand how PC’s higher heat deflection temperature and glass transition temperature influence part performance and long-term stability.
Attention to rheological behavior, drying discipline, and mold geometry details enables lower defect levels, better dimensional stability, and dependable performance from both resins. Consistent focus on these factors—particularly molecular integrity that remains invisible after ejection—delivers the strongest long-term outcomes on the shop floor.
