The surface pitting and poor smoothness of PVC pipes are mainly caused by insufficient plasticization, imbalanced lubrication system, and poor dispersion of fillers.

To solve such problems, the first step is to appropriately increase the temperature of the extruder body and die by 5-10 ℃, ensuring that the material is fully plasticized and reducing the pitting caused by unmelted particles.

Secondly, it is necessary to optimize the lubrication system, control the amount of external lubricant, and avoid excessive addition of PE wax, oxidized wax, etc., which may cause uneven dispersion. At the same time, an appropriate amount of internal lubricant should be used to enhance the plasticizing effect. It is recommended to use active lightweight calcium carbonate as filler and control the addition ratio to reduce surface defects caused by poor filler quality or excessive dosage.

In addition, adding ACR processing aids in moderation can effectively promote plasticization, enhance melt strength, and significantly improve the surface smoothness of pipes. If impact modifiers such as MBS are used in the formula, attention should be paid to controlling the amount added and ensuring that the raw materials are dry to avoid pitting caused by mismatched plasticizing speed or moisture absorption. By comprehensively adjusting temperature, lubrication, formula, and process, it is possible to effectively eliminate pitting and make the surface of PVC pipes brighter and smoother.