Common Blow Molding Process

Plastic molding processing is an engineering technology, which involves various processes to convert plastics into plastic products, so there are three common plastic processes: extrusion, injection molding, and blow molding.

1. Injection molding

 the principle is to add granular or powdery raw materials into the hopper of the injection machine, and the raw materials are heated and melted into a flowing state. Under the push of the screw or piston of the injection machine, they enter the mold through the nozzle and the pouring system of the mold cavity, hardened and shaped in the mold cavity. Factors affecting the quality of injection molding: injection pressure, injection time, injection temperature.

2. Extrusion molding

Extrusion molding, also known as extrusion molding, is mainly suitable for the molding of thermoplastics, and is also suitable for the molding of some thermosetting and reinforced plastics with good fluidity. The molding process is to use the rotating screw to extrude the heated and melted thermoplastic material from the die head with the desired cross-sectional shape, then shape it by the shaper, and then pass it through the cooler to make it harden and solidify to become the desired cross-sectional shape product.

3.Blow molding

Blow molding is to clamp the molten thermoplastic raw material extruded from the extruder into the mold, and then blow air into the raw material. The molten raw material expands under the action of air pressure and fits to the wall of the mold cavity. The method of finally cooling and solidifying into the desired product shape. Blow molding can be divided into film blow molding and hollow blow molding.

Film blow molding is to extrude the molten plastic from the annular gap of the extruder die into a cylindrical thin tube, and at the same time blow compressed air into the inner cavity of the thin tube from the central hole of the die to inflate the thin tube to a diameter Larger tubular film.

Hollow blow molding is a secondary molding technology that uses gas pressure to inflate a rubber-like parison closed in a mold cavity into a hollow product. It is a method of producing hollow plastic products.

For more information about plastic molding machines, please do not hesitate to contact Alps machine.