Polystyrene（PS）

(1) Barrel Temperature

Feed Zone:   30-50°C (50°C)

Zone 1: 160-250°C (200°C)

Zone 2: 200-300°C (210°C)

Zone 3: 220-300°C (230°C)

Zone 4: 220-300°C (230°C)

Zone 5: 220-300°C (230°C)

Nozzle: 220-300°C (230°C)

Temperatures in parentheses are recommended starting points at 35% and 65% stroke utilization, with flow length to wall thickness ratio of 50:1 to 100:1.

(2) Melt Temperature: 220-280°C

(3) Barrel Residence Temperature: 220°C

(4) Mold Temperature: 15-50°C

(5) Injection Pressure: 80-140 MPa (800-1400 bar). The melt has excellent flow characteristics - avoid excessively high pressure.

(6) Holding Pressure: Typically 30-60% of injection pressure, with relatively short duration.

(7) Back Pressure: 5-10 MPa (50-100 bar). Insufficient back pressure may cause air bubbles (appearing as grey streaks in parts).

(8) Injection Speed: Generally fast. Use multi-stage injection based on part geometry. For thin-walled packaging containers, inject as fast as possible (consider using an accumulator if needed).

(9) Screw Speed: High speeds permitted (max. peripheral speed 1.3 m/s), but slower plastication is recommended for optimal results, similar to the cooling process.

(10) Metering Stroke: (0.5-4)D (min-max). The 4D stroke provides adequate residence time for the melt, which is crucial.

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

(12) Pre-Drying: Not required. If stored in poor conditions, dry at 80°C for 1 hour.

(13) Regrind: Up to 100% regrind possible.

(14) Shrinkage: 0.3-0.6%.

(15) Gating System: Pin-point gates; heated hot runners, insulated hot runners, internal bushings. Relatively small cross-sections are sufficient.

(16) Machine Shutdown: No specific purging required with other materials; PS withstands temperature rises.

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