Step 1: Transform the plastic memory
Plastic Extrusion starts off with resin or nurdles being fed from a hopper into a barrel. The material is heated and rotated in the barrel, while a screw pushes the melted plastic through a screen plate, which helps to remove any contaminates and help transform the plastic memory from rotational to longitudinal. The process is similar to Injection Moulding – what changes is that it is continuous.
Step 2: Form the plastic
Once the plastic has been fed through the screens, it is fed through the die. The die is what gives the product its profile and this changes, depending on the final product requirement.
Step 3: Cool the plastic
After the product has been extruded, it needs to be cooled. Typically, cooling baths are used, where the plastic is pulled through water. In the case of sheet extrusion, the process requires cooling rolls.
The Plastic Extrusion method changes depending on the process needed for the final product.