Research on the drum suppression method for long-distance reverse thinning spinning of the ultra-thin-walled cylinder

To address the instability phenomenon caused by the continuous increase in the drum height during the long-distance spinning of ultra-thin cylindrical parts, the evolution and influencing factors of the drum height during the spinning process are studied by combining both theory and experiment. The parameters that can be used to restrain the increase in the drum height are obtained and successfully applied to the long-distance thinning spinning process of ultra-thin cylindrical parts. First, combined with the spinning model, the constraint boundary, metal flow and stress field of the spinning contact zone are analysed, and the formation mechanism and influence parameters of the drum shape during the spinning of the thin-walled cylinder are obtained. Next, by performing a numerical simulation, the influence law of the parameters (thinning rate and feed rate) on the height of the drum is obtained, and an experimental verification is performed. Based on the change rate of the drum height as the selection basis of the parameter interval, the method of reducing the thinning rate of each pass and increasing the spinning pass is selected to suppress the continuous increase in the drum height during the long-distance spinning of thin-walled cylinders. Finally, through the fine-tuning of the parameters, the long-range stability spinning of a thin-walled cylinder with a diameter of φ398 mm is realized (the wall thickness is reduced from 2 to 0.53 mm, and the spinning length is extended from 1030 to 3800 mm). The results show that the thinning rate is the main parameter affecting the change in the drum height when the parameters of the machine tool, mandrel, workpiece and rotating wheel are fixed. The spinning pass and reduction in each pass can be determined with the thinning rate not exceeding 45%, which can effectively control the increase rate of the drum height and prevent the instability phenomenon caused by the continuous increase in the drum height during the long-range spinning of the ultra-thin cylindrical parts. The findings provide theoretical and experimental guidance for the long-distance stability spinning of ultra-thin cylindrical parts.