Before commencing production, the rubber extruder must first be brought up to temperature. Once the set temperature is reached, the equipment can be started, and rubber is fed into the extruder’s feeding system. As the rubber enters the barrel, it is heated and plasticized, while the screw subjects it to shearing, compression, mixing, and other processing steps. The material is then extruded through the die to form the desired product shape. During continuous operation, the rubber interacts with the barrel and screw, generating frictional heat that raises the temperature. If the temperature in the barrel becomes too high, the rubber may undergo thermal degradation or even scorching inside the barrel. Therefore, when producing rubber products, it is essential to maintain the barrel and screw at a stable, controlled temperature. We typically use mold‑temperature control units to regulate the temperature of each section of the barrel. When the temperature reaches the preset upper limit, the system automatically activates a cooling water circuit to lower the barrel and screw temperatures. As the cooling system operates, the temperature gradually decreases. Once the temperature drops to a predetermined level, the control system ceases cooling, and the machine continues running. In this way, the extruder maintains a consistent operating temperature, ensuring an optimal production environment.

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 dimensions. Furthermore, cold‑feed extrusion is less sensitive to pressure fluctuations and offers greater operational flexibility, while requiring lower capital and operating costs.

3. 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.