Plastic extrusion machines convert raw materials into finished solid-length plastic products. These machines liquify raw plastic pellets through a thermal process and mold the molten plastic into different shapes. Extrusion machines support mass production, are cost-effective, and provide high customization, which makes them suitable for producing different plastic products.
Machine Types
Plastic extrusion machines are categorized into screw-type and non-screw-type extruders. Screw-type extruders include single-screw, twin-screw, three-screw, split twin-screw, and vented extruder. The non-screw type includes a ram extruder which uses a plunger or ram. Here’s a detailed discussion of each of these extruder machines:
Single Screw Extruder
This type of extruder forms the basic model of extrusion machines in plastic production. These machines work by feeding the raw material into an extruder barrel and melting it using a single screw. The molten material is then extruded using a mold to produce the desired shape of the finished plastic product.
Single-screw extruders are cost-effective, simple to use, and reliable. They have a slow extrusion speed and long residence time, which makes them suitable for pellet processing. These machines are used in the production of plastic pipes, sheets, plates, and small auxiliary profiles.
Twin-Screw Extruder
This type of extruder machine uses two screws to rotate melted plastic inside a barrel. Twin-screw extruders have a fast extrusion speed and a large output, which makes them suitable for mass production. These machines are self-cleaning and have a short residence time, which makes them suitable for powder processing. They can use mixed PVC material directly, which enhances the grinding of waste and reduces the granulation process. While these extruders are more expensive than the single-screw type, they are faster and yield higher-quality composite products. These machines are used in the production of PVC plastic window and door profiles. They are also used in modifying matrix resin.
Twin-screw extruders can either be co-rotating or counter-rotating. The co-rotating type consists of two screws of the same size rotating in the same direction. Screws in the counter-rotating type rotate in opposite directions. The counter-rotating twin-screw extruder has softer shearing and higher conveying and decompression capacity than the co-rotating type.
Three Screw Extruder
This machine contains three screws arranged in a line rotating in the same direction. The screws are designed to operate as two pairs of twin screws. This increases the output, improves the mastication effect, and minimizes energy consumption. Three screw extruders also have two meshing areas, which shorten the screw length and enhance operational efficiency.
Split Twin Screw Extruder
The split twin screw extruder is based on twin screw extruder design. This plastic extrusion machine contains a screw that is sleeved on the mandrel screw block. The screw has an advanced design and the barrel is integrated. It allows adjustments between the screw block and barrel bushing. This advanced design allows the machine to be used in various processes including extrusion, material transportation, and plasticization.
Vented Extruder
A vented extruder contains an exhaust port at the center of the barrel. The exhaust port helps to release gas that builds up during certain extrusion processes. The presence of the exhaust eliminates the drying processes required in ordinary plasticization. This saves time and makes the extrusion process less labor-intensive. Vented extruders are suitable for processing polymer materials with high hygroscopicity, such as nylon.
Ram Extruder
A ram extruder can either be vertical or horizontal. This extrusion machine employs the stamping principle to push material forward using a plunger. The plunger pressure extrudes plasticized material from a die to create a molding effect in the barrel. To reduce the effect of intermittent feeding on the extrusion process, modern ram extruders use double plungers. Ram extruders produce plastic products with uniform and bubble-free thickness. They also minimize material loss.
How to Choose the Right Plastic Extruder
Determine the raw materials to be processed and the desired finished product. This will help you get a machine that can process your raw materials and yield a finished product with the right shape and quality. You will also need to evaluate the performance of the extrusion machine. This involves assessing the machine’s load capacity, total yield, and energy consumption value. Select a machine that delivers a high output with minimal energy use.
Get the Right Extruder for Your Plastic Extrusion Project
The various types of plastic extrusion machines available in the market are designed to perform specific processing tasks. Investing in the right type of machine will facilitate the success of your extrusion project. Contact an experienced manufacturer of plastic extruders today to help you choose the type that fits your project.