PVC foam board surface of the head with a streamlined flow path, two and a half mould design, mould head collapse, clean easy. Manual fine-tuning elastic modulus lip or portable upper die lip design, in order to suit the different thickness of sheet extrusion. Vertical or inclined *5 ° choke rod design, to adapt to the different viscosity of molten material flow to get uniform distribution. Die using imported high-quality die steel or alloy steel, in order to prolong the life of the mold.