The Basics of the Plastic Extrusion Process
Professionals in the plastic industry often rely on extrusion to create quality plastic products. Using this technique, workers melt plastic material to force it into a die for shaping, and then they cut the formed shapes to length. This process results in durable plastic products with consistent cross sections.
Plastic extrusion is also more affordable than other plastic molding processes. When facing large orders that necessitate high production rates, it’s clear why so many professionals choose this process over slower, more costly alternatives. Materials built using plastic extrusion include:
- Weather stripping
- Plastic sheeting
- Wire insulation
- Adhesive tape
What Is the Plastic Extrusion Process?
Plastic extrusion owes its efficiency and affordability to its straightforward design process. First, workers place raw resin into an extruder’s hopper, which pushes it through a high-temperature barrel that heats it to its melting point. Once the material reaches the end of the barrel, it gets squeezed through a screen pack into a feed pipe leading to the die, which is where the molten plastic cools and solidifies.
Barrier Screws vs. Mixing Screws
Plastic extrusion equipment relies on the successful use of two types of screws.
Barrier screws prevent molten plastic from enveloping pellets as the plastic transitions away from the extrusion screw. These screws keep molten and solid plastic separated from one another in the transition section, which keeps solids from fully melting by mistake. This allows liquid plastic to pass through one channel, while solids remain separated from the molten solution.
Mixing screws are ideal for extruding materials. These screws operate using side-by-side twin extruders. In this setup, two screws rotate against each other to mix materials. In some cases, systems with mixing screws may feature kneading blocks designed to operate normally and in reverse, which ensures thorough mixing.
Materials That Can Be Extruded
Several varieties of plastic perform well during extrusion. Some of the most commonly used materials include:
- Nylon, including nylon 6, nylon 6/6 and nylon MDS
- Polyethylene, including low- and high-density variants
- Acetal, in copolymer
- Polypropylene, in copolymer and homopolymer configurations
Plastic extruders can form these materials into sheets, strips, rolls, or coils depending on your needs. You can also choose from a wide array of colors when designing your product, although color capacities can vary by manufacturer.
Before embarking on a plastic extrusion project, you should ensure your project’s tolerances match the capabilities of the material being used. Material thicknesses vary tremendously, which could result in unintended outcomes.
Extrusion Excellence from New Process Fibre
At New Process Fibre, we strive to create the highest-quality plastic solutions that can stand the test of time against adverse environmental and artificial conditions. If you would like to learn more about some of plastic extrusion’s capabilities, check out our new interactive infographic!
If you would like to learn more about how you can apply plastic extrusion to your next project, be sure to contact us today!