Plastic Processing Methods


Injection Molding	This method is the most widely used for plastic manufacturing. Heated liquid plastic is forced into a cool mold and then set to harden. Once the plastic hardens the mold halves are taken apart and you are left with the finished product.
Blow Molding	This method is used to create hollow plastics. This process forces compressed air into a molten plastic core. Similar to a balloon. The air pressure forces the liquid plastic to the sides of the mold. The mold is cooled and then removed, and you are left with a seamless hollow container.
Thermoforming	This method utilizes a malleable sheet of plastic. The plastic sheet is heated, and then pressed mechanically into a mold or pulled into a mold with air pressure. When air pressure is used it is referred to as vacuum forming.
Transfer Molding	This method uses heat and pressure to form liquid thermosetting plastics. It is used to create intricate items with holes or deep pockets. This more fluid plastic is easier to work around detailed mold elements.
Reaction Injection Molding	This production technique alternates layers of liquid plastic and fiber glass. The resulting product is ultra-strong and durable making it less likely to warp.
Compression Molding	This method uses two thermosetting materials squeezed simultaneously into a mold with pressure and heat. Then a powdered plastic material is added. This causes a chemical reaction and hardens the desired form.
Extrusion	This method is typically used for continuous production. The raw material is fed in at one end and heated. It then is forced through a stationary form to create products like plastic film, and piping. The molded plastic cools as it is pushed through the form. It can then be cut to desired lengths along a conveyor belt.