What is the difference between a parallel twin screw barrel and a single screw extruder

A Twin screw barrel for extruder is a machine that has two screws rotating in opposite directions. Its positive displacement capability facilitates the pumping of hard-to-feed materials. Another benefit is that it offers better temperature control and can process heat-sensitive materials. A twin-screw extruder is a versatile tool that can perform a wide range of functions. However, it requires more capital investment.The screw barrel clearance has a direct relation with the quality of the plasticized product. Too big a clearance will result in a low shear rate and a poor plasticizing effect. It will also cause severe back-flow, which will reduce output. The material will also burn easily. The screw clearance should be at least 0.200 mm.A screw barrel with the correct size and shape is crucial for the successful manufacturing of your plastic extruder machine. The right screw barrel will increase the productivity of your process.

Twin extruder Bimetal screw and barrel
Twin extruder Bimetal screw and barrel
The bimetallic barrel for single screw extruder is a kind of barrel spray 2-5mm thick alloy coat on the barrel inner wall which has excellent corrosion resistance, abrasion resistance and high working temperature. And its useful service life is greatly improved contrast to common nitrided barrel. Bimetal has more obvious advantages when processing special plastics to enhance the abrasion life, such as engineering plastics, fluoride plastics, PPO etc. Our company use special alloy powders being sprayed and welded on the top of screw flights, and use different alloys and welding methods.

A good screw barrel will make your machine more efficient and less prone to failure.Parallel twin screw barrel for plastic extruder machines are one of the components in the plastic extrusion process. They are used to produce different types of plastic materials. Some of these products include PVC pipe, PVC profile, extrusion foaming products, and more. Those using the machine should make sure to buy high-quality barrels and screw.The screw configuration of parallel twin screw extruders is better than those that have conical screws. The difference lies in the rotation direction. There are two types of twin screw barrels: co-rotating and non-rotating twin screw barrels.A co-rotating twin screw barrel has the two screws rotating simultaneously, while a non-rotating twin screw barrel has two screws rotating in opposite directions.Twin screw extruders are widely used in plastic extrusion processes. They are often used in special processing operations for hard-to-feed materials, as well as for profile extrusion.

These twin screw extruders also feature positive displacement capability, which improves flow rate by reducing the sensitivity of the flow rate to pressure. In addition, they are suitable for processing heat-sensitive materials. The only disadvantage of twin screw extruders is that they require higher capital investment, but they have many advantages.High friction heat in a single-spew plastic extruder machine occurs due to the material's friction. In this situation, material becomes compacted in the screw and is transferred to the liner and screw surface, causing the material to stick together. This results in high frictional heat and an increased amount of energy. High friction heat also increases the risk of material cracking and material breakage, so it is vital to design the screw and housing in a way that the materials are compaction-free over a short distance.

When considering the types of materials, it is important to consider the flow rates of the feed and exit zones. This is essential for a stable and effective operation. The feed screw must be cooled to prevent pellet formation and the temperature must be controlled to avoid overheating the barrel. The temperature of the water jacket must be kept within a certain range, as too low a temperature may weaken the friction between the raw material and the barrel. Furthermore, a high water jacket temperature can reduce the bearing capacity of the motor, causing the machine to oscillate in rotation speed.The friction between the screw and barrel is important to the material conveyance. The high friction along the barrel is required to move material forward, while low friction along the screw is necessary to allow the material to exit at the speed needed for a line. To balance the opposing frictional forces, a grooved barrel feed section is needed. Additionally, low-friction extruder screws provide improved metering and consistency of output.