Inside the workshop of Qingdao SunKai Marine Supplies Co., Ltd., the production of dock rubber fenders is in full swing. Fenders aren’t ordinary rubber products—they must withstand the enormous force when ships berth. That’s why every step, from rubber mixing to carcass forming, is carefully refined. Technicians adjust formulas based on real-world use: busy ports get more natural rubber for toughness, while corrosive sea areas receive additives for better weather resistance. The raw materials are mixed at 120℃ with repeated pressure release to remove air bubbles, then pressed into thick sheets for the main body and thin sheets for edges.
At the forming station, a steel inner core is fixed on a rotating platform, and rubber sheets are wound together with dipped nylon cord fabric, layer by layer. Hydraulic rollers press each layer to eliminate gaps. The surface facing ships is reinforced with a 50mm-thick rubber layer and double-layer cord fabric, 30% denser than other areas. This design spreads the force of impacts and has doubled the service life of fenders in heavy-use ports.
Before vulcanization, all carcasses go through static testing. Ultrasonic scanners check for hidden defects, and inspectors double-check dimensions against the design. In one batch, tiny gaps found during testing were fully rewound to ensure nothing is overlooked. “Fenders are the first line of defense at ports. Even tiny flaws can create risks,” says the quality head, showing SunKai’s commitment to delivering reliable, long-lasting fenders.
Contact us today to learn more about our high-performance dock rubber fenders and secure your port’s safety with SunKai solutions.
