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.
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.
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.
Read more: What is Plastic Extrusion?