In extrusion machines, the core shaft is a crucial component that primarily functions to transfer torque from the gearbox to the screw element, thereby driving the screw element to rotate and perform critical operations such as melting, plasticizing, homogenizing, and extruding of materials. This includes transferring torque, supporting the screw, and ensuring processing quality. Common types of core shafts include traditional spline milled core shafts and cold rolled core shafts. The core shaft is essential for achieving the melting, plasticizing, homogenizing, and extruding of materials, and its precision and strength directly affect the machine’s operational stability and the final product’s quality.