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Working principle of a rubber extruder

Time：

2020-09-24

Working Principle of a Rubber Extruder 1. Working Principle Extrusion molding is a process in which plasticizable rubber compound is continuously forced through a die under specific conditions, thereby forming a product with a defined cross-sectional shape. As the compound advances along the screw, mechanical and thermal effects cause changes in its viscosity and plasticity, transforming it into a viscous fluid. Based on the changes occurring during extrusion, the working section of the screw is generally divided into three main zones according to their functions: the feeding zone, the compression zone, and the metering (or extrusion) zone. 2. Advantages of Cold-Feed Extrusion: It eliminates the need for heat‑treating equipment, facilitates mechanization and automation, and moreover…

Working principle of a rubber extruder

1. Operating Principle

Extrusion molding is a manufacturing process in which a plasticizable compound is continuously forced through a die under specific conditions, thereby producing a product with a defined cross-sectional shape.

As the rubber compound advances along the screw, mechanical and thermal effects cause changes in its viscosity and plasticity, transforming it into a viscous fluid. Based on the material’s behavior during extrusion, the working section of the screw is typically divided into three distinct zones—feeding, compression, and metering—each serving a specific function.

2. Cold-feed extrusion

Advantages: It saves on hot‑melt processing equipment, facilitates mechanization and automation, and, thanks to the extruder’s enhanced screw shear and plasticizing action, ensures uniform temperature and plasticity of the compound. It also improves the quality of extruded products, enhances surface finish, and produces semi‑finished extrudates with more stable and consistent dimensions. Furthermore, cold‑feed extrusion is less sensitive to pressure fluctuations and offers greater operational flexibility, while requiring lower capital and operating costs.

3. Compression Section: Also known as the plasticization section, this segment extends from the onset of rubber compound melting to the point when the entire compound becomes flowable. The compression section receives the rubber lumps delivered from the feeding section, compacts them, further softens them, and expels any entrained air back toward the feeding section.

4. The metering section, also known as the compression section, further pressurizes and mixes the material conveyed from the compression zone, at which point the compound in the screw channels has reached a fully developed flow state. The rotation of the screw drives the material forward, and it is extruded uniformly through the die channel at a specified rate and pressure.

5. Equipment Features

Suitable for extruding rubber compounds (EPDM, natural rubber, nitrile rubber, butyl rubber, and reclaimed rubber), it is used in the production of composite sealing strips for architectural doors and windows, single‑extruded sealing strips, as well as various dense and foamed rubber products—such as strip‑shaped, bar‑shaped, tubular, and sheet‑like items—for applications in construction, electrical appliances, machinery, water conservancy, and other industries.

Cold-feed rubber sealing strip extruder: This is a type of equipment that uses cold rubber for production, with forced cold feeding as the standard feeding method. Cold-feed rubber extruders are characterized by high production efficiency and stable operation. Extruders are commonly used to manufacture products such as sealing strips and rubber hoses that can be produced via extrusion. An extruder is a rubber‑processing machine employed to extrude tread compounds, inner tubes, rubber hoses, and various rubber profiles.

Hebei Shuangda Rubber and Plastics Machinery Co., Ltd. is a modern enterprise integrating research and development, manufacturing, and sales of complete sets of extrusion equipment for rubber, silicone, and plastics. The company’s main products include rubber extruders, rubber hose extrusion lines, three‑layer composite sealing strip extrusion lines, silicone sealing strip production lines, plastic sealing strip production lines, plastic profile production lines, plastic pipe production lines, elastomer extruders, and other extrusion equipment, as well as production machinery for engineering seals, automotive seals, wire and cable applications, air‑conditioning hoses, braided hoses, automotive hoses, waterstop strips, and related products.