It’s always important to know the ins and outs of every difficult process right? To me mostly yes, but the other day my friend was talking about what he learned about in his college class, something by the name of plastic manufacturing. Interested to learn more on a college worthy topic I listened to his brief description. I was fascinated by how many simple things can be made out of plastic, things I never took a second to think was plastic! I learned that Plastic extrusion is a manufacturing process when plastic is put into a large heater, melted, shaped, and cut to length. As I was eager to learn a little more I did some research and asked a couple people their knowledge on plastic extrusion. The results were a lot of people had mixed reactions on knowing what it was or not!

I found it interesting how my use of adhesive tape everyday must be the product of plastic extrusion or simple things such as window frames. AS the process begins, small beads of plastic are fed into a heated extruder cavity or cylinder.

Usually the beads are mixed with colorants before the extrusion process begins. In some plastic extrusion processes UV inhibitors are mixed in as well. Once actually inside the machine, the beads are pushed through an opening in the extruder cavity towards a screw like mechanism. The screw rotates forcing the plastic material through.

Inside the heater the temperature reaches about 400 degrees in order to match the melting point of the plastic beads. Overheating tends to be a problem, so three separate heaters are used in the process the gradually increase the heat inside of the cavity.

Friction and pressure serve as separate source of heat that is independent from the heaters. And in some cases the friction might conduct so much heat the actual heaters for the extruder are shut off. The pressure and friction maintain at the desired temperature.

After the high temperatures cooling fans are also employed frequently, helping to keep the plastic extrusion cavity at the desired temperature. Now it’s time for the plastic to go into a die. The die gives the plastic its profile after the die, the plastic must be cooled again.

This process is also called the Polymer Extrusion Process. The program I intensely payed attention too showed every aspect I was willing to learn about this process. After the cooling is complete, it’s time for the plastic to be cut to size. The product can also be spooled, coiled, or cut to length. Materials such as Aluminum and rubber are examples of extruded parts of the plastic. The extrusion process is used every day for household items, city structures, and simple things as tape. But no one realizes that plastic products are made from extruding plastic. After everything is cooled, it is now time for the plastic to coiled or cut to length.

Many plastic companies create different ways of extruding plastic that are used to create different types of products. injection molding is also something I want to check out and get more information on. Overall my research on Plastic extrusion and injection molded products really fulfilled my mind that I accomplished something and almost mastered the art of Plastic extrusion.

- Gregory Smith

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