Thin-wall cover body machining method and machining auxiliary tool

The invention discloses a thin-wall cover body machining method and an auxiliary machining tool, which are characterized in that a proper hard alloy cutter and cutting parameters are selected according to the special machining characteristics of TC4 titanium alloy so as to finish rough and finish machining of a workpiece; for workpiece deformation caused by stress generated in the part machining process, two times of vacuum heat treatment annealing are carried out in the machining process; in order to solve the problems of cutter vibration and the like caused by the thin wall in the finish machining process, a special auxiliary reinforcing tool is designed, paraffin is used between the auxiliary tool and a workpiece to reinforce the rigidity of the workpiece, and various cutter vibration and deformation problems in the finish machining process are solved. The machining auxiliary tool comprises an upper fixing ring, a lower fixing ring, a tool body and a bottom plate, the tool body and the bottom plate are fix