In an extruder, the raw material is melted and formed through the head into a cylindrical parison (molten tube), which is sandwiched between split mold blocks. High-pressure gas is blown in to force the walls of the parison out against the inner surfaces of the mold, forming a hollow, shaped object.

When a continuously extruded parison has reached a specified length, it is sandwiched between the split mold blocks and simultaneously cut off with a knife. The mold is then calibrated to enable air to be blown in to form an object.

Several to dozens of molds are clamped to the outside edge of a rotary wheel, which revolves to enable a parison to be supplied into each mold in a continuous sequence. Once a parison is inside a mold, it is closed and air is blown in for forming.

Plastic pellets supplied through a hopper are melted and kneaded in a heating cylinder. The molten material is then forced into the mold cavity by an injection unit such as a screw conveyor. Once the plastic material has cooled and solidified, the mold is opened and the molded object is pushed out by an ejector.

Thermoplastic resin sheet is heated and softened with a heater, to which a mold is closely attached, and the air between the mold and the sheet is removed by a vacuum pump. The sheet is pressed onto the mold by atmospheric pressure, and then allowed to cool and solidify.

Plastic pellets supplied through a hopper are softened and melted in a heating cylinder. The moltenmaterial is extruded using a screw conveyor to form a continuous molding with uniform cross-sectional geometry.