Acrylonitrile Butadiene Styrene (ABS)

(1) Barrel Temperature

Feed Zone: 40–60°C (50°C)
Zone 1: 160–180°C (180°C)
Zone 2: 180–230°C (210°C)
Zone 3: 210–260°C (240°C)
Zone 4: 210–260°C (240°C)
Zone 5: 210–260°C (240°C)
Nozzle: 210–260°C (240°C)

Temperatures in parentheses are recommended as baseline settings for a stroke utilization of 35% and 65%, with a melt decompression setting similar to the feed stroke, within a range of approximately S₀ = 1–0.1.

(2) Barrel Constant Temperature: 220°C

(3) Mold Temperature: 40–80°C

(4) Injection Pressure: 100–150 MPa (1000–1500 bar)

(5) Holding Pressure: The holding time is relatively short; holding pressure should be 30%–60% of the injection pressure.

(6) Melt Temperature: 220–250°C

(7) Back Pressure: 5–15 MPa (50–150 bar). If back pressure is too low, air entrapment in the melt may cause burning (appearing as dark streaks in the part).

(8) Injection Speed: A graduated injection profile from slow to fast is recommended to achieve good surface finish, minimal internal weld lines, and strong weld seam strength. Venting channels should be provided at weld line convergence points.

(9) Screw Speed: Maximum screw surface speed should be 0.6 m/s. It is preferable to set a lower screw speed, as long as plastication is completed before the end of the cooling time.

(10) Metering Stroke: (0.5–4)D

(11) Cushion: 2–8 mm, depending on metering stroke and screw diameter.

(12) Pre-Drying: In some cases, ABS can be processed directly without pre-drying, but drying at 80°C for 3 hours is recommended. Moist pellets can cause cracks, surface marks, or bubbles in the part.

(13) Regrind Ratio: Up to 30% regrind can be used, provided the material has not undergone thermal degradation in prior processing.

(14) Shrinkage: 0.4%–0.7%

(15) Gating System: Pin-point gates and hot runner systems can be used. Minimum wall thickness should not be less than 0.7 mm due to the relatively low flowability of ABS.

(16) Machine Downtime: No purging with other material is required.

(17) Barrel Equipment: Standard screw, non-return valve, open nozzle