Extruder used for PVC low foaming products making can be either single-screw extruder or double-screw extruder. Proper extruder should be selected by manufacturer as per the specific requirements of PVC foaming products and real situation of manufacturers. After years of practice in PVC foaming products industry, some basic experience in PVC low foaming products making is concluded for reference.
　　

Requirements for extruder used for moulding and extrusion of PVC low foaming products are as below:-

(1) Power for extruder transmission system shall be sufficient and match the extrusion output;

(2) Slenderness ratio of extruder’s screw shall be high enough to establish stable extrusion

   pressure;

(3) The extruder must have enough melt pressure in case that foaming process occurs ahead of

   schedule;

(4) Extruder’s screw(s) should have high performance of mixing and plasticization to make sure  

   that PVC resin is well mixed and plasticized with all kinds of auxiliary agents.

(5) The extrusion system should have good performance of wearing and corrosion resistance;

(6) Precision of extruder’s temperature control system should be higher than that of ordinary

   extruders;

(7) The extruder should have stable transmission and fluctuation of speed should be smaller

   than ordinary extruders.