The parallel co-rotating twin screw extruder has become a cornerstone of the plastic blending industry. As manufacturers and users demand more innovative designs, new concepts and customizations are frequently applied to these extruders. One critical component of this system is the barrel, which varies depending on the specific requirements of the customer, as well as the formulation and processing needs.
There are several different barrel designs used in parallel co-rotating twin screw extruders:
Open Barrel: Typically used for feeding and exhaust processes, these barrels have openings at the top, allowing easy access for material input and venting.
Closed Barrel: These barrels are completely sealed with no openings, designed for processes that do not require external feeding or venting during extrusion.
Closed Side Feeder Barrel: While there is no opening on top, a side opening connects to the side feeder, which is useful in processes requiring precise side feeding.
Upper & Side Opening Barrel: This structure features both a top and side opening, making it ideal for processes requiring exhaust functionality in a compact layout, with side feeding capabilities.
Liquid Injection Machine Barrel: A small threaded hole on top connects the barrel to a liquid injection gun or valve, allowing for the controlled injection of liquids into the extruder.
Building Block Barrel: Highly interchangeable, this structure allows different sections of the barrel to be swapped out, akin to building blocks. Its high machining accuracy ensures consistency and is favored for flexibility in operations.
Split Barrel: This barrel can be opened into two parts, much like a shell. It is widely used in research settings where easy cleaning and accessibility are priorities.
The performance and durability of the extruder barrel heavily depend on the materials used. Different processes require different materials for optimal functionality:
45 Steel + C-Type Liner Bushing Barrel: A cost-effective solution with wear-resistant alloy liners, typically featuring an 8-hole bushing design.
45 Steel + α101 (Iron Chromium Nickel Carbide Steel) Liner: A bimetallic liner structure known for high hardness (HRC 60-64) and wear resistance, commonly used in applications involving glass fiber reinforcement.
Nitrided Steel 38CrMoAla Barrel: This material offers high hardness and corrosion resistance, ideal for processing corrosive raw materials. It features a hard outer surface with a softer inner core for durability.
HaC Alloy Barrel: Known for its superior corrosion resistance, this type is often used in fluoroplastics due to its high anti-corrosive properties.
316L Stainless Steel Barrel: This material provides excellent corrosion and rust resistance, making it a popular choice for applications in the food industry.
Cr26, Cr12MoV Liner Barrel: A high-cost-performance barrel with ultra-high chromium powder alloy, offering exceptional wear resistance.
Powder Nickel-Based Alloy Liner Barrel: This holistic liner is an excellent choice for its combined wear and corrosion resistance, often used in high-demand environments.
Imported Powder Metallurgy Liner Barrel: Known for its superior performance in corrosive and wear-intensive conditions, this type of liner offers both ultra-high wear resistance and corrosion protection.
As the parallel co-rotating twin screw extruder continues to dominate the plastic processing industry, its barrel structure and materials play an essential role in its performance. The choice of barrel type—whether it’s an open, closed, or building block design—and the material used—ranging from standard 45 steel to advanced powder metallurgy—are crucial to meeting the demands of various extrusion processes. Customizing these components based on specific needs ensures greater efficiency, durability, and precision in production.
