PVC soft door curtain equipment, during production, the surface is not smooth and has pits/particles. The phenomenon is: the surface of the door curtain is rough, with small bumps or white particles, and in severe cases, it feels rough to the touch.
Key Causes:
Raw Material Issues: PVC resin powder clumps due to moisture (moisture content > 0.3%), uneven dispersion of plasticizers/stabilizers and other additives, or impurities mixed in the raw material (such as dust, plastic debris);
Equipment Issues: Extruder barrel/screw wear (excessive clearance leading to uneven plasticization of the raw material), presence of burnt material or foreign objects in the die runner (lack of regular cleaning);
Temperature Issues: Extruder front-end temperature too low (raw material not fully melted), or rear-end temperature too high (localized overheating and carbonization).
Solution:
Raw Material Pretreatment: Pre-dry PVC resin (80~90℃ for 2~3 hours), and thoroughly mix additives using a high-speed mixer (1000~1500r/min, mix for 10~15 minutes);
Equipment Maintenance: Disassemble the mold and clean the runner of any slag (use a copper brush + special cleaning agent to avoid scratching the runner), and check the screw wear (replace the screw if the gap exceeds 0.5mm);
Temperature Adjustment: Increase the front-end temperature by 5~10℃ (e.g., for soft PVC materials, front-end 140~150℃, middle-end 160~170℃, die head 170~180℃).
