Plastic scorch is a common quality defect in the plastic extrusion process. Symptoms include: excessively high temperature readings; a large amount of smoke from the die; a strong, pungent odor; a crackling sound in severe cases; burnt particles in the extruded plastic layer; and continuous bubbles at the glue seam.
The main causes are:
1. Temperature control is too high, exceeding the plastic's thermal degradation temperature.
2. The screw has not been cleaned for a long time, allowing accumulated scorch to be extruded with the molten plastic.
3. Prolonged heating or downtime causes the plastic in the barrel to be heated and decomposed.
4. Out-of-control or inaccurate temperature control instruments can cause high-temperature decomposition.
5. The extruder's cooling system is not activated, causing overheating due to shear friction.
