East China's Self-developed Centrifugal Casting for Paper Mill Equipment

      Paper production relies heavily on stable and high-performance machinery components to sustain continuous operation and consistent paper quality. Key cast parts such as dryer cylinders, guide roll shells, suction roll sleeves and machine frame rings directly affect the operating efficiency of paper lines and end product performance. Traditional sand casting methods for paper machinery parts usually involve lengthy production cycles, intensive manual work, and relatively high risk of internal defects like pores and shrinkage cavities. These defects may lead to leakage, uneven operation or shortened service life of equipment, and further cause production interruptions and paper quality fluctuation. To solve these pain points and match the actual demand of in-house equipment support and upgrading, a paper mill in East China has independently developed a dedicated centrifugal casting process based on its own production needs and accumulated technical advantages.

      Centrifugal casting is a forming method that injects liquid metal into a high-speed rotating mold. Driven by the centrifugal force generated by the rotating mold, liquid metal spreads evenly along the inner wall of the mold cavity, completes the filling process and solidifies into the target shape gradually. Different from general-purpose centrifugal casting technologies directly introduced from outside, this self-developed process is adjusted and optimized targeting the structural features of paper machinery components, such as cylindrical dryer cylinders, roll sleeves and annular frame parts. The targeted design makes the process highly compatible with the paper mill’s existing production and maintenance system, and avoids the mismatch between universal technology and actual paper industry application scenarios.

      Compared with traditional casting methods, this centrifugal casting process shows obvious advantages in production organization and operating cost. First, it reduces labor input in the production process. The highly mechanized operation mode cuts down manual links in mold filling, demolding and finishing procedures, lowering the dependence on manual work in component production. The automated operation rhythm also stabilizes production efficiency and reduces fluctuations caused by human factors. Second, the process effectively shortens the manufacturing cycle. Centrifugal force accelerates the mold filling speed of liquid metal, and the solidification process is more efficient than that of traditional gravity casting. The shortened production cycle of cast parts enables faster equipment maintenance and spare part replacement, reducing unplanned downtime of paper production lines.

      In terms of component performance, the centrifugal force field changes the solidification sequence of liquid metal and makes the metal structure compact. It reduces internal defects such as pores and shrinkage cavities inside the castings, which is critical for paper mill equipment like dryer cylinders that work under pressure and high temperature. Cast rolls produced by this process have good concentricity and uniform surface structure, which helps maintain stable operation of the paper machine, reduce paper web breakage and thickness deviation, and support stable paper quality output. For cylindrical and sleeve parts widely used in paper machines, the centrifugal casting process can achieve near-net-shape forming, reducing machining allowance in subsequent processes and saving metal material consumption.

      This self-developed centrifugal casting process adapts to various metal materials commonly used in paper machinery, including cast iron, alloy cast iron, carbon steel and alloy steel. It can be applied to the production of dryer cylinders, guide roll shells, suction roll sleeves, press roll sleeves and annular frame components, covering the demand of cultural paper, packaging paper and specialty paper production lines. The mill can adjust process parameters such as rotation speed, pouring temperature and cooling rate according to the requirements of different equipment parts, to match the production of castings with different specifications and performance requirements.

      The R&D and application of the process rely on the technical accumulation of the paper enterprise in East China. The whole process follows standardized production control specifications, from liquid metal smelting, mold preheating, centrifugal pouring to final demolding and inspection. Stable process parameters ensure consistent quality of castings in batch production, and reduce performance differences between different batches of parts. The enterprise continues to iterate the process based on actual equipment operation feedback, optimizing key links such as mold material matching and pouring control.

      For the paper mill, the self-developed centrifugal casting process provides a feasible path for equipment upgrading without large-scale transformation of existing production support lines. The process can be connected with the original equipment management system, and gradually replaces part of the traditional casting supply for spare parts. While improving the supply efficiency of equipment parts, it also supports the optimization of equipment performance, and helps the enterprise cope with the increasingly competitive market environment in the paper manufacturing industry.