Abstract: In order to eleminate the spinning instability caused by drum-shaped instability in the spinning process of ultra-thin cylindrical parts, the key factors and laws affecting the stability are studied and determined on the basis of the analysis of the mechanism of drum type formation and instability. Combining with the characteristics of drum-shaped instability during the spinning of thin-walled cylinder, the boundary constraint, metal rheology and stress field in spinning contact area are analyzed to obtain the forming mechanisms of drum and mode-locked ring during spinning process. Based on the numerically simulated results of multiple sets of parameters, the influences of clearance between workpiece and mould, thinning rate, feed rate and diameter-to-thickness ratio on drum shape ratio and drum stiffness are analyzed, and the selection range of the corresponding parameters is determined by using the drum shape ratio and drum stiffness as the parameters of drum shape state. The spinning parameter adaptability and long-stroke spinning experiments of thin-walled cylinder with 2.00 mm in thickness and 398 mm in outer diameter were carried out on a three-roller spinning machine. After 3 passes of spinning, the wall thickness of the thin-walled cylinder was reduced from 2.00 mm to 0.53 mm, and its length was extended from 1 030 mm to more than 3 800 mm. Through the study of drum formation and influencing factors, it provides theoretical and experimental basis for the development of spinning parameters and long-range stability spinning of large-diameter ultra-thin cylindrical parts. Key

Key words: thinningspinning, drumshaperatio, drumstiffness, clearanceratio, thinningrate, feedrate, diameter-to-thicknessratio