There are many different ways to form shapes and components out of plastic. While injection molding is ideal for many parts and components and can accommodate shapes of all types, it is not at all practical for the production of tubes with simple to complex interior profiles.
A better option for this is the choice of custom plastic extrusion. Understanding how this process works is helpful in determining if this is the right option for your specific part or component in moderate to high volume production situations.
The Basics of the Process
Extrusion is a process that is used with metals, composite materials as well as with plastics. In this process, the raw plastic or resin is fed into a hopper or bulk holding container. This hopper feeds the resin beads into an auger or screw-type of conveyor that transfers a continuous supply of the beads to the end of the machine.
The barrel, which surrounds the screw or auger, is heated to the melting point of the specific resin. This is often done incrementally along the barrel, with the temperature increasing the closer the resin gets to the die.
The melted plastic reaches the die, and the pressure from the constant feed of resin by the screw pushes it forward, and screens prevent any backflow. The thick, melted plastic passes through the die, and this creates the internal profile and the exterior tube shape.
Cooling for Quality Control
A vacuum system maintains a constant pull on the formed tube and allows for uniform cooling as the long, continuous form leaves the die. Cooling rolls or air cooling is the final step in custom plastic extrusion.
With the options to create a wide range of interior shapes and profiles, the process of custom plastic extrusion is swift, efficient, and results in precise shapes to meet any required tolerances.
