Blow Molding Industry Heating Elements

Creating a Plastic Bottle

2706bottle.jpgWe manufacture ceramic and mica heater bandsthat are used in the plastic extrusion manufacturing process. Call us on 0121 772 00 33 today for an instant quote.

Blow molding is a highly developed molding technology, originally founded in the late 1800's for the production of celluloid baby rattles. Its usage is most appropriate in the manufacture of basic hollow items (such as plastic bottles) that have uniform wall thicknesses. In December of 1942 the first polyethylene bottle was made using blow molding technology, signalling the birth of what was to become a massive industry that today produces billions of plastic bottles annually worldwide using heating elements.

Blow molding technology requires substantial amounts of heat to be applied at specific stages of the process. This heat is provided by band heaters. Typical band heater applications include heating the barrels of extrusion and injection moulding machinery, heating blown film dies and heating other cylindrical objects. The heat from the band heaters maintains the molten plastic temperature and hence its fluid state and other essential characteristics, whilst it is being transported to the mold or extruder. Band heaters are generally made up of an elongated electric heating element, an electrical insulator and a multipart outer shell assembly that contains the heating element and insulation and provides for heat transfer from the band heater.

There are four different types of blow molding used in the production of plastic bottles, jugs and jars: Extrusion, Injection, Stretch and Reheat. The basic process begins with the heating of a thermoplastic resin to a molten state. This substance is then extruded through a die head to form a hollow tube called a parison, which is dropped between two mold halves. The mold halves close around the parison after which it is inflated. As the parison is cooled inside the mold the plastic hardens. Finally, the mold opens and a new plastic bottle is born!