Blow molding is a manufacturing process used to produce hollow plastic parts, such as bottles and containers, through a sequence of carefully controlled steps. The process begins with melting plastic in an extruder, which pushes the molten plastic through a die head to form a hollow tube known as a parison. This parison is positioned between two open mold halves, which then close around it and grip it in place. A blow pin is inserted into the top of the parison, and compressed air is blown in, causing the plastic to expand and conform to the shape of the mold cavity. Cooling lines within the mold help solidify the plastic. Once the material has cooled, the mold opens and the molded product is removed. The product is then trimmed to remove any excess plastic and is ready for the next stage of production.
