What is Plastic Extrusion?

Nicole Madison
Nicole Madison
Nicole Madison
Nicole Madison
Plastic extrusion is used in the production of wire insulation.
Plastic extrusion is used in the production of wire insulation.

Plastic extrusion is a manufacturing process through which plastic is melted, shaped into a continuous profile, and cut to length. This process is used in the production of a wide variety of items, including piping, wire insulation, and plastic sheeting. Even adhesive tape and window frames include extrusion as part of their manufacturing processes.

Plastic pellets used for plastic extrusion.
Plastic pellets used for plastic extrusion.

In this process, raw plastic is fed into a heated extruder cavity or cylinder. Typically, the raw plastic is in bead form and may be mixed with colorants before the extrusion process begins, and in some methods, ultraviolet (UV) inhibitors may be added to the raw plastic beads as well. Once inside the machine, the plastic beads and any accompanying material move through an opening in the extruder cavity towards a screw mechanism. The screw rotates, forcing the plastic material to advance through the cavity.

Extrusion is included in the manufacturing process of window frames.
Extrusion is included in the manufacturing process of window frames.

Inside the cavity, the temperature is very high, often reaching about 400°F (200°C), which melts the plastic. Many exturders involve the use of three different heaters set to gradually increase heat inside the cavity. This reduces the potential for overheating.

Friction and pressure within the cavity serve to produce extra heat that is independent of the heaters. Sometimes, the pressure and friction inside the cavity produces so much heat that the heaters may be shut off. When this happens, the desired temperature is maintained by the friction and pressure. Cooling fans are also employed frequently, helping to keep the machine at the desired temperature.

Extrusion is included in the manufacturing process of adhesive tape.
Extrusion is included in the manufacturing process of adhesive tape.

When the molten plastic reaches the front of the barrel, it moves away from the screw and journeys through a special screen designed to filter contaminants out. The molten plastic then moves into a die, which is responsible for giving the molten plastic its profile. The plastic must then be cooled, often by a sealed-water bath; care must be taken to prevent the collapse of the newly formed product in its still molten state. Plastic sheeting and certain other products are cooled by special cooling rolls instead of water baths.

Plastic tube.
Plastic tube.

After cooling, the product is spooled, coiled, or cut to length. In addition to plastics, a variety of other materials, including aluminum and rubber, may be extruded. Even clay and certain types of foods may be produced this way. The process used may differ from that employed for the purpose of plastic extrusion, however.

Nicole Madison
Nicole Madison

Nicole’s thirst for knowledge inspired her to become a wiseGEEK writer, and she focuses primarily on topics such as homeschooling, parenting, health, science, and business. When not writing or spending time with her four children, Nicole enjoys reading, camping, and going to the beach.

Nicole Madison
Nicole Madison

Nicole’s thirst for knowledge inspired her to become a wiseGEEK writer, and she focuses primarily on topics such as homeschooling, parenting, health, science, and business. When not writing or spending time with her four children, Nicole enjoys reading, camping, and going to the beach.

You might also Like

Readers Also Love

Discussion Comments

lusidarubber

What is plastic extrusion? Well, this is the production method wherein the plastic will be melted and molded into a constant profile and will be sliced to length. This particular manufacturing process is primarily used in producing a wide selection of items which include piping, plastic sheeting and wire insulation. Plastic extrusion is added to the entire manufacturing processes for window frames and adhesive tapes. You may also encounter some companies that are performing this production procedure in making some custom rubber products.

www.lusidarubber.com

BookWhisk

Once the relatively high cost of the die is paid for, plastic extrusions are quite inexpensive.

Post your comments
Login:
Forgot password?
Register:
    • Plastic extrusion is used in the production of wire insulation.
      Plastic extrusion is used in the production of wire insulation.
    • Plastic pellets used for plastic extrusion.
      Plastic pellets used for plastic extrusion.
    • Extrusion is included in the manufacturing process of window frames.
      Extrusion is included in the manufacturing process of window frames.
    • Extrusion is included in the manufacturing process of adhesive tape.
      Extrusion is included in the manufacturing process of adhesive tape.
    • Plastic tube.
      Plastic tube.
    • Clay can be extruded from a grinder to form long tubes.
      Clay can be extruded from a grinder to form long tubes.