Brief introduction of PVC-DWV foam core pipes-5

6.Precautions

(1) The inner and outer skin layers and the foamed core layer materials of the PVC core foamed pipe should be mixed in two high-speed mixers respectively.

(2) Before production, the uniformity of the assembly gap between the die and the core rod in the molding mold should be carefully adjusted. When the gap is uneven during production and affects the wall thickness, only fine-tuning can be performed.

(3) Before production, the distance between the die and the sizing sleeve is generally controlled within the range of 120 to 200 mm. During production, the distance should be adjusted based on the actual situation. If the core layer material foams faster, the distance between the two should be adjusted smaller, otherwise it should be larger.

(4) In addition to the different specifications of the extruders for the skin and core layers (the specifications of the core layer extruder are slightly larger than those of the skin layer extruder), attention should also be paid to the matching of the extrusion melt speed in the two extruders. During the initial production, observe the consistency of the molding thickness and melt flow rate of the inner and outer layers and the core layer extrusion materials in the pipe blank, and then adjust the screw speed of the two extruders appropriately.

The End.