Model XJ-75 XJ-90 XJ-120 XJ-150 Screw Diameter (mm) 75 90 120 150 Length-to-Diameter Ratio 20:1 20:1 20:1 20:1 Motor Power (kW) 30 55 110 132 Screw Speed (r/min) 30–65 30–60 30–50 30–50 Production Rate (kg/h) 80–180 100–300 180–540 500–750 Working Principle Extrusion molding is a manufacturing process in which a plasticized rubber compound, under specific conditions, is continuously forced through an extrusion die to produce a product with a defined cross-sectional shape. As the rubber compound moves forward along the screw, mechanical and thermal effects cause changes in its viscosity and plasticity, transforming it into a viscous fluid. Based on these changes during extrusion, the working section of the screw is generally divided into three main parts according to their functions: the feeding section, the compression section, and the extrusion section. The characteristics of each section are as follows: 1. Feeding Section: Also known as the solid conveying section, this segment extends from the feed port until the rubber compound begins to melt. After entering the feed port, the compound undergoes relative motion between the screw grooves and the inner wall of the barrel under the pushing action of the rotating screw, forming compacted rubber lumps. 2. Compression Section: Also called the plasticizing section, this part spans from the onset of melting until all the rubber compound becomes fully flowable. The compression section receives the rubber lumps delivered from the feeding section, compacts them, further softens them, and expels any entrapped air back toward the feeding section. 3. Extrusion Section: Known as the metering section, this stage further pressurizes and mixes the material conveyed from the compression section. At this point, the rubber compound within the screw grooves has reached a fully fluid state. The rotation of the screw drives the material forward, ensuring uniform extrusion through the die channel at a consistent rate and pressure.

Model XJ-75 XJ-90 XJ-120 XJ-150 Screw Diameter (mm) 75 90 120 150 Length-to-Diameter Ratio 20:1 20:1 20:1 20:1 Motor Power (kW) 30 55 110 132 Screw Speed (r/min) 30–65 30–60 30–50 30–50 Production Capacity (kg/h) 80–180 100–300 180–540 500–750 Applications Suitable for extruding various types of rubber (EPDM, natural rubber, nitrile rubber, butyl rubber, reclaimed rubber), used in the production of composite sealing strips for building doors and windows, single-extruded sealing strips for automobiles, as well as dense and foamed rubber products in strip, rod, tube, or sheet forms for construction, electrical appliances, machinery, water conservancy, and other industries. Working Stages The process is divided into four stages: In the first stage, the machine must feed material, convey it, and compact the compounded rubber; in the second stage, the rubber compound must be heated and plasticized to become a more fluid mass; in the third stage, the extruder mixes and thermally homogenizes the compounded rubber; and in the fourth stage, pressure must be built up to force the compounded rubber through the die. For hot-feed extruders, the second and third stages are provided by a preheated open mill. Cold-Feed Equipment Operation and Maintenance 1. Before use, add 25–30 kg of oil to the hardened gear reducer (refer to the oil level indicator). Use gear oil in summer and No. 45 mechanical oil in winter. Regular oil changes can extend the service life of the reducer. 2. Periodically open the fixed cover of the cold-feed unit every 1–2 months to perform routine maintenance on the feeding system, adjust the clearance between the copper knife and the feeding roller, and check the roller bearings. Failure to do so may result in rubber leakage. Additionally, lubricate the cold-feed gears with grease once per shift. 3. Prior to starting up, calibrate the die diameter and tighten all flanges and fasteners. 4. Operating temperature should be maintained between 40°C and 70°C. Temperatures that are too low can damage the machine, while excessively high temperatures may cause rubber vulcanization (over‑curing), leading to equipment failure and impaired operation. 5. Before shutting down, ensure all rubber has been completely extruded from the barrel and screw, then cool the barrel and screw using circulating water until they reach room temperature; otherwise, this may affect subsequent use. 6. Winter operating precautions: Before freezing conditions set in, add antifreeze to the circulating water to prevent ice formation and potential equipment damage.