Extrusion System Malfunction
1. Rough, dull outer surface of the pipe: Adjust the process temperature; clean the die; maintain the cooling water temperature between 20–25°C.
2. Grooves or roughness on the inner wall: Lower the core temperature; squeeze the tube blank tightly to seal the inner cavity immediately after startup; clean and polish the mold.
3.Yellowish-brown streaks or spots on the surface of the pipe: Clean the dead corners of the mold; inspect the raw materials and improve the mixing process.
4.Bubbles on the surface of the pipe: Clean the vent holes and piping; slightly lower the die temperature.
Dimensional and Geometric Defects
1. Uneven wall thickness: Check the heating coils; maintain a steady pulling speed; adjust and tighten the mold bolts.
2.Pipe ovality exceeds specifications: Adjust the nozzle to ensure even cooling; maintain water temperature at ≤35°C; install a correction device.
3.Outer diameter out of tolerance: Maintain a stable vacuum level and pulling speed; adjust or replace the sizing sleeve.
Vacuum and Molding Problems
1. No vacuum or low vacuum: Clear the inlet and tubing; inspect and repair air leaks; use a thin wire to clear the small holes in the core mold.
2.Adjust the flow uniformity of the sizing sleeve; ensure that the vacuum in the rear chamber is slightly higher than that in the front chamber; check the discharge from the main unit.
Troubleshooting for Feeding and Cutting Issues
1. Unstable current in the main unit: Check the feeder; repair the motor; check the heater; remove the screw to inspect and adjust the shims and components.
2.Abnormal equipment vibration: Check and adjust the equipment's level and alignment; adjust the screw clearance; replace worn parts; reinforce the base.
3.Main motor fan failure causing shutdown: Immediately reduce the load, install an external fan for forced cooling, and promptly repair or replace the faulty motor.
Post-welding Issues
1. Electrofusion welding abnormality: Stop welding, allow the joint to cool, and then resume the operation; check whether the resistance of the fitting is within the standard range (e.g., for a DN110 fitting, it should be 0.8–1.2 Ω).
2.Hydraulic system failure on the hot-melt butt welding machine: Top up the hydraulic fluid to the specified level; inspect the high-pressure hoses and quick-connect fittings.