Machine Overview

Wanrooe double-stage pelletizing lines handle feedstock with high moisture and high contamination — materials that would fail in single-stage systems. The first stage uses an exhaust-type barrel and screw to degas and remove moisture and volatile contaminants. The second stage employs a shorter L/D extruder for final plasticization and filtration, delivering stable, consistent extrusion pressure to the pelletizing head.

Startup Procedure

Step 1 — Preheat — Heat the barrel for 4–5 minutes. Once temperature begins rising, manually rotate the motor via the drive belt 8–10 times to ease startup load. Continue heating for another 10 minutes before starting the main motor. Maintain heating during production — different polymers require different setpoints.

Step 2 — Temperature stability — Keep barrel temperature stable once running. Fluctuation causes output inconsistency. Maintain approximately 200 °C at the vent zone through to the die head for standard materials.

Step 3 — Feed consistently — Material must feed uniformly and at adequate rate. Match feed speed to screw speed. Too fast causes overload and poor degassing; too slow causes starvation and output surges.

Step 4 — Shutdown — Cut main power completely. Remove the die head wire plug with a wrench. Preheat independently before next use — never start cold.

Operating Rules

Run forward only — Reverse rotation damages screw and barrel alignment. Verify motor phase wiring before first startup.

Never feed cold — The machine must be at operating temperature before material enters. Cold feeding causes material to solidify on the screw root, creating a stuck-screw condition that requires teardown.

Keep contaminants out — Iron, stones, and other debris at the inlet or vent port cause catastrophic damage. Install magnetic separators upstream and inspect feedstock before loading.

In-Process Monitoring

Melt temperature check — Periodically touch the extrudate strand with a clean hand. If it sticks, the melt is too cold — increase barrel temperature immediately. Normal strand should feel warm but not tacky.

Gearbox maintenance — If the reducer runs hot or produces noise, stop for inspection and lubrication. Do not operate with degraded oil or worn bearings.

Bearing lubrication — Both main shaft bearings should run cool and quiet. If they feel hot to touch or emit noise, stop and add grease. Under normal operation, grease both bearing housings every 5–6 days.

Overall machine condition — Monitor temperature displays, screw speed, and motor current continuously. Address deviations immediately before they escalate to failures.

Vibration check — If the machine shakes or rocks, inspect the coupling alignment and gap. A too-tight coupling transmits excessive vibration; loosen slightly and recheck.

Need Support?

Contact us for installation supervision, operator training, or troubleshooting guidance. Provide your material type, contamination level, and target capacity when requesting service or spare parts.

FAQ: Double-Stage Pelletizer Operation

Why does my machine keep jamming at startup?

Almost always cold feeding or insufficient preheat. Allow full warm-up time — 15 minutes minimum for standard polymers, longer for engineering plastics. Verify all heating zones reach setpoint before introducing material.

How often should I change the gearbox oil?

First change at 500 operating hours, then every 2,000 hours or 6 months whichever comes first. Use only the specified oil grade. Contaminated oil causes bearing failure and gear wear.

What causes surging output from the die?

Surging indicates inconsistent feed rate, partial blockage in the vent zone, or temperature fluctuation. Check feeder calibration, clean the degassing port, and verify heater function in the compression zone.