What is Plastic Extrusion?
Plastic Extrusion (also known as polymer extrusion) is a process of manufacturing long products that have constant cross section, by forcing the softened polymer through a die opening.
By using a plastic extrusion process, the products like rods, pipes, sheets, wire insulation coatings, etc can be manufactured.
Plastic extrusion is also used to manufacture small shaped components which can be cut from the long extruded part.
Plastic extrusion process (steps)
Plastic extrusion process is shown in the above image. But, let me tell you the step by step process of plastic extrusion in detail.
The polymer material which is to be extruded is initially in the form of pallets.
This polymer material is fed into the extruder from the hopper as shown in the image above.
The material is then allowed to move forward with the help of a feeding screw.
It is then forced through a die opening which results in a continuous extruded polymer.
The heating elements are placed inside the barrel as shown in the above diagram.
These heating elements soften and melt the polymer material inside the barrel before it is extruded through a die opening.
The temperature required for melting the polymer can also be adjusted by observing the thermocouple readings.
For cooling of the extruded polymer, either air is blown or the extruded polymer is passed through the water bath.
Plastic extrusion process is a continuous process in which the extrusion of polymers continues as long as the raw pallets are supplied.
In plastic extrusion process, the polymers used are generally thermoplastics polymers. But by this process, the elastomers and thermosetting plastics may also be extruded.
The thermoplastics polymers that are extruded by this process can be further formed by the thermoforming method.
By using plastic extrusion, the plastics can be formed at a very high rate (for example, plastic pipes can be formed at the high rate of 900 kg/hr).
Plastic extrusion examples
There are various day to day life examples of plastic extrusion products which are listed below.
#1) Water pipes or sewage pipes
#2) Plastic pipettes
#3) Drinking straws
#4) Window frames
#5) Wire sleeves
Plastic extrusion: Image by Ikiwaner, CC BY-SA 3.0, via Wikimedia Commons
Plastic pipette: Image by Nadine, CC BY-SA 3.0, via Wikimedia Commons
Wire sleeves: Image by Sander.savi, CC BY-SA 4.0, via Wikimedia Commons