The extrusion process is used to manufacture parts that are cross-sectionally uniform across their entire length. Although extrusion is most commonly used to produce metal components, plastics and rubbers can also be used such as PVC, ABS, polypropylene and polyethylene.
The solid plastic or rubber pellets are placed in a hopper mounted at the top of the extruder. The force of gravity then moves the material into the barrel, where they are heated and melt into a liquid, which is then moved out of the other end of the barrel by a motor-driven screw. Once the material has exited the barrel, it moves into the die - a custom-manufactured tool featuring an opening in the shape of the required cross-section of the component. As the material is forced out of the die, it takes on its profile, meaning that long lengths of extruded material can be created with cross-sectional consistency. The extrusions are then cooled in a water bath to allow them to properly solidify, before being cut to length.
Plastic and rubber extrusion is typically a continual production process, with material pellets constantly being fed into the hopper. Therefore, it is great for producing long material lengths in a short space of time, making high-volume production fast and simple.
