Method of forming thick-walled cylinder by spinning

A method of molding a cylinder though extrusion and rotation, comprising:

• (1) placing a cylindrical blank at a geometric center of a lower mold cavity;
• wherein a bottom of the lower mold cavity is provided with a straight hole;
• a blank block is arranged at the straight hole;
• a diameter of the blank block is the same as that of the straight hole;
• the blank block is configured to support the cylindrical blank;
• the lower mold cavity has a wavy-shaped inner wall in circumferential direction;
• the lower mold cavity has a taper in a vertical direction;
• and an area of the cross section of the lower mold cavity decreases from a top to a bottom;
• (2) fixedly arranging the lower mold cavity on a rotating worktable such that the cylindrical blank is directly below an upper indenter;
• driving the upper indenter to move vertically downwards by an extruder, so as to extrude the cylindrical blank to perform an extrusion process;
• and
• simultaneously driving the lower mold cavity by the rotating worktable to rotate uniformly around a central axis of the cylindrical blank;
• wherein the upper indenter is cylindrical;
• and a diameter of the upper indenter is the same as an inner diameter of the cylinder;
• (3) after the extrusion process is completed, keeping the upper intender still;
• and keeping the lower mold cavity rotating uniformly;
• and
• (4) moving the lower mold cavity vertically upwards while being driven by the rotating worktable to rotate to allow the wavy-shaped inner wall of the lower mold cavity to process an outer surface of the cylindrical blank by rotation;
• and separating the lower mold cavity from the blank block to allow a formed cylinder to be separated from the lower mold cavity to obtain the desired cylinder.