Rubber extruder

Rubber extruders can produce a wide variety of products, with rubber sealing strips and rubber hoses being among the most common. The type of extruder used depends on the specific product, but regardless of the model, the fundamental operating principle remains the same. Before starting the extruder, it is essential to raise the temperature of the barrel and screw to the desired set point; only when this temperature is reached should the machine be operated. Once heated, the rubber’s flow characteristics improve, and as the screw rotates continuously, it subjects the material to shearing, compression, and compounding within the barrel. The extruder then conveys the rubber toward the die, where it is shaped and extruded. Temperature control is typically achieved via a mold‑temperature controller, though the specific equipment used varies between extruders. Moreover, different rubber products require distinct temperature profiles at various stages of processing, which must be configured according to the product’s specifications. Throughout the production process, all critical operations—pressure and temperature—are managed within the barrel. Selecting an extruder with the appropriate configuration is crucial to meet the demands of the intended product.

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 main unit’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 dimensional tolerances. Furthermore, cold‑feed extrusion is less sensitive to pressure fluctuations and offers greater operational flexibility, while requiring lower capital and production costs.

3. Equipment Features

Suitable for extruding rubber compounds—such as EPDM, natural rubber, nitrile rubber, butyl rubber, and reclaimed rubber—this equipment is used to produce composite sealing strips for architectural doors and windows, single‑extruded sealing strips, as well as a wide range of dense and foamed rubber products in various shapes, including strip‑shaped, tubular, and sheet‑like forms, 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, and its feeding system typically employs forced cold feeding. 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 designed 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.