PVC floor, plastic films, and insulated wires; What do these three items have in common? At first glance, most people are quick to say they all come from the same substance (thermoplastic), which, of course, is correct. But there is something else. Have you ever questioned how these materials are made to have the definite shape which they exhibit? Well, to answer the initial question, these items are all made using the same process, which is called plastic extrusion.
Understanding the intricacies of the plastic extrusion process enables manufacturers to make better-informed decisions related to the various pieces of machinery and even the end-products.
Plastic Extrusion Process
In simple terms, plastic extrusion is the process of passing plastics in either solid or granule form into a heated barrel and then into the mold, which has a specific shape that forms the end-product.
Plastic Extrusion Process Steps
In detail, the extrusion process involves:
- Passing a mixture of plastic raw material and additives (if any) through a hopper onto a chamber with a rotating screw,
- That rotates and pushes the plastic forward through a heated barrel.
- The heat from mechanical shear and the barrel now converts the plastic into a melt,
- That is later forced through a die with an opening to create the desired profile.
Types of Plastic Extrusion Machines
The plastic extrusion process earlier mentioned only takes place in a machine designed for this purpose, and they usually come in various forms and even operational modes. You have:
Single Screw Extruder
Just as the name, it has only one rotating screw in the barrel. They are the most popular type of extruders in the industry because they produce relatively simple designs but are also cost-effective and durable. Single screw extruders might not offer the best solution for efficient mixing of the raw feed and other additives, but they do a decent job either way.
Multi Screw Extruders
They have more than one screw in their heating barrel and are often classified according to the number of screws and the pattern of rotation of the screw. You have the twin-screw extruders (the most popular), quad screw extruders, and planetary roller extruders for the former.
Twin or Double Screw Extruders
Double screw extruders type of extrusion machine has two rotating screws in the heating chamber. It works either in a co-rotating, counter-rotating, or co-axial mode to introduce mechanical shear and push the molten plastic to the die. Their various modes of operation imply that they are more complex than single-screw extruders. But they also provide better and homogeneously mixed melt than their other counterpart.
Some other types of extruders include: Ram extruders. Ram extruders use a hydraulic ram plunger in place of a rotating screw to push the melted plastic from the heated chamber to the die. You also have disk extruders and gear pumps as other forms of extruders.
Advantages of Plastic Extrusion
Haven dedicated the bulk of this post to the plastic extrusion process and the various forms of plastic extrusion machines. We understand that most people are more interested in its benefits.
The plastic extrusion process is often necessary in the plastic manufacturing process for several reasons.
- It produces large product volumes within a short time.
- The plastic extrusion process is usually less expensive to operate and set up than other plastic production processes like injection molding.
- Plastic extrusion supports the use of additives that helps improve the various properties of the end-product.
- The process creates a continuous cross-sectional product that can be cut into a variety of shapes and lengths.
What are the Applications of Plastic Extrusion?
Relevance of the plastic extrusion process applies to its end products, which have several use cases across the board, from manufacturing to construction and regular everyday consumer items.
For the sake of brevity, we would be narrowing the end-use to the following:
Poly-Vinyl Chloride (PVC) sheets are just one of the line-ups of products that come from the plastic extrusion process. This material has many use like making pipes, window and door profiles, cable insulations, medical devices, and a lot more.
We can say the same in construction. Many flooring materials (mostly made up of PVC) utilize plastic extrusion processes to create these widely used materials in home décor.
Although the plastic extrusion process may have been around for a while now. It still offers terrific of the simplest and cheapest ways to produce plastic products.
Manufacturers are nonetheless tasked with the responsibility of choosing what type of plastic extrusion machine and even the production line to use as it goes a long way in affecting the desired end-product.
If you are constantly in the market for plastic extrusion machines and their various production lines (SP, PP, WPC PVC, etc.). Boyu should be your first choice. They produce many products to choose from and even offer post-sale services to manufacturers that help enhance the production process.
Most importantly, Boyu continues to push the boundaries of R&D. So you can see the latest technological advancements in the plastic manufacturing industry for years to come. Visit their website for more information about their products and services.
Featured Image by Dejan Kotze