PC/ABS combines the toughness and heat resistance of polycarbonate with the processing stability of ABS, making it widely used in automotive interiors, electronic housings, and industrial components. Stable molding depends on proper moisture control, balanced temperatures, and controlled shear conditions.
Drying Requirements
Moisture management is one of the most important preparation steps in PC/ABS molding. Excess moisture may cause silver streaks, splay marks, bubbles, and reduced mechanical performance.
| Parameter | Recommended Range |
|---|---|
| Drying temperature | 80–100°C |
| Drying time | 3–4 hours |
| Target moisture content | < 0.02% |
Pro tip: A dehumidifying dryer is generally preferred over a standard hot-air oven because it provides more stable low-humidity conditions. If bubbling or vapor appears from the nozzle during purging, additional drying may still be required.
Barrel and Mold Temperature Settings
PC/ABS processing typically uses barrel temperatures between 220°C and 260°C, depending on grade formulation and part geometry.
| Barrel Zone | Typical Range |
|---|---|
| Feed zone | 200–220°C |
| Compression zone | 220–240°C |
| Metering zone | 240–255°C |
| Nozzle | 245–260°C |
Thin-wall parts and long-flow geometries often require higher melt temperatures to maintain flow stability before gate freeze occurs. During extended production interruptions, many processors reduce barrel temperatures or purge the material to minimize thermal degradation and discoloration.
Recommended mold temperatures generally range from 60°C to 80°C.
Injection Pressure and Speed
Higher pressures are often required for thin-wall sections, small gates, or long flow paths. Proper holding pressure helps reduce sink marks and dimensional variation, especially around ribs and thicker sections.
Multi-stage injection profiles are often used for complex geometries. Faster initial filling followed by reduced speed near the end of fill can improve flow stability and surface appearance.
Common Processing Adjustments
Several molding defects can often be linked to processing conditions. The table below outlines common issues and initial adjustment strategies:
| Defect | Possible Adjustment |
|---|---|
| Short shot | Increase melt temperature or injection pressure |
| Silver streaks | Improve drying conditions |
| Sink marks | Increase holding pressure or holding time |
| Flash | Reduce injection pressure |
| Warpage | Optimize mold temperature and cooling balance |
If defects remain after parameter adjustment, the root cause may also involve gate design, venting, wall thickness transitions, or material degradation.
For a broader overview of material properties and application selection, refer to our complete PC/ABS alloy guide: PC/ABS Alloy Guide
