Every day, you use something made using plastic extrusion. Whether it’s the straw you’re drinking with, or the bag lining your trash can, plastic extrusion has played a role in your life. 

Plastic extrusion is a method of molding plastic into long shapes with a continuous cross-section. Plastic weatherstripping, pipes, tape, and wire insulation are just some of the products made through the plastic extrusion process. 

Plastic extrusion is a fast and cost-efficient way to manufacture common everyday objects while maintaining a high level of consistency. 

Read on if you’ve ever been curious where plastic tools and parts come from, or if you are wondering if extrusion is right for your business!

Types of Plastic Extrusion

There are two main types of extrusion: Screw design extrusion and blown film extrusion. The first is for objects that need to hold their shape, while the second is for thin, flexible sheets of plastic. 

Screw Design 

This version of plastic extrusion involves a long metal barrel with a die on one end and a hopper on the other. Plastic beads in the hopper are gravity-fed into the barrel. Inside the barrel is a long screw or auger that pulls the beads along. 

As the beads move through the barrel, they are gradually heated to high temperatures, and they melt into a viscous fluid. The heating process must be gradual to avoid creating imperfections in the plastic, like bubbles or wrinkles. 

The screw pushes the plastic fluid through the die, which gives the plastic its final shape. The plastic is immediately fed into a trough full of water, where it can cool before losing its shape. At that point, it’s ready to be cut and packaged for distribution or further preparation. 

Blown Film 

Blown film extrusion starts very similar to screw design. You still have a hopper feeding plastic beads into a barrel, heating the beads as they are pulled along by an auger. 

But at the other end of the barrel, there is no simple die. Instead, the tube takes an upward turn, and the plastic is extruded vertically through a very thin circle. 

In the middle of this circle is a long metal rod that expels air. The thin, flexible plastic blows up like a very long balloon. High above, rollers pull the plastic along. By the time it reaches the rollers, the plastic has cooled enough to touch another surface without re-melting or sticking. 

Finally, the resulting sheets of plastic are rolled onto a spool and are ready for distribution. 

Getting the Most From the Extruder

What we’ve covered here are the essential parts needed for the plastic extrusion process. However, there are some additional tools you will want to invest in to ensure your machine is running optimally. 

Extrusion machines work best when protected by thermal blanket isolation. These blankets reduce the amount of heat lost by your machine by an average of 85 percent. That saves you a lot of money, and takes a huge amount of stress of your machine, reducing the cost of maintenance. 

Read on here to learn more about thermal blanket insulation.