Application of Basic Equipment for Rubber Sealing Strips

During production, rubber sealing strips are typically extruded using a rubber extruder, which is why many people refer to it as a rubber strip extruder. Whether it’s a single‑extrusion seal or a composite seal, the manufacturing process relies on an extruder. To select the appropriate type and model of extruder, we must consider the seal’s dimensions and structural requirements. For instance, when producing single‑extrusion seals, we choose an extruder whose extrusion capacity matches the product’s size. Before operation, the extruder’s barrel and screw must be preheated. Additionally, we adjust the formulation based on the desired product quality and production cost. After being processed in a mixer or open mill, the raw rubber can be fed into the extruder’s feeding system for production. Once the rubber reaches the required temperature, the main drive is activated, and the material is introduced. As it enters the barrel via the feed system, the rubber is preheated, its flow characteristics improve, and the rotating screw begins to convey it forward, subjecting it to shear and compression. The rubber then moves progressively toward the die head, where it is shaped and formed. Following extrusion, the finished product passes through a hot‑air curing oven and a cooling tank to achieve proper cooling and dimensional stabilization, completing the sealing‑strip manufacturing process.

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 production 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 fields.

Cold-feed rubber sealing strip extruder: This is a type of equipment that uses cold rubber for production, typically employing 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, which 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 that integrates 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.