The blow process (or blow extrusion) is indicated when you want to manufacture hollow parts with a neck diameter smaller than the diameter of the rest of the part. PVC blown parts are usually used for food, cosmetic, mineral water and other beverage packaging, as well as for hygiene and cleaning products, lubricants and fuel additives, etc.

Blowing consists of plastifying the PVC compound with the aid of a plastification cylinder equipped with electrical resistance and a screw. The plastified material passes over a mold forming a type of hose, while still heated, called parison. The parison should be lodged within the mold for the blowing pin to inject air into it, making the material assume the shape of the mold cavity.