Ball Spin Forming for Flexible and Partial Diameter Reduction in Tubes

Abstract

This paper proposed a new ball spin forming equipment, which can form a reduced diameter section on the halfway point of a tube. The effects of forming process parameters on the surface integrity and deformation characteristics of the product were investigated. The proposed method can reduce the diameter in the middle portion of the tube, and the maximum diameter reduction ratio was over 10% in one pass. When the feed pitch of the ball die was more than 2.0 mm/rev, spiral marks remained on the surface of tube. Torsional deformation, axial elongation and an increase in thickness appeared in the tube during the forming process. All of them were affected by the feed pitch and feed direction of the ball die, while they were not affected by the rotation speed of the tube. By sending the ball die towards the fixed part of the tube or by increasing the feed pitch, torsional deformation and elongation decreased, and the amount of thickening increased. When the tube was pressed perpendicularly to the axis without axial feed, a diameter reduction ratio of 21.1% was achieved without defects using a ball diameter of 15.9 mm. The polygonization of the tube was suppressed by reducing the pushing pitch. The ball spin forming has a high advantage in flexible diameter reduction processing on the halfway point of the tube for producing different diameter tubes.

Mechanical analysis of 20/316L bimetal composite pipe formed by spinning

“…The forming technology of metal composite pipe mainly includes hydroforming, drawing forming, explosion forming and spin forming [7][8][9][10]. Many scholars and https://doi.org/10.1007/s42452-021-04932-7…”

Latest Hydroforming Technology of Metallic Tubes and Sheets

“…The first group is tube hydroforming (THF) [1][2][3][4][5][6][7][8][9], in which a hydraulic media and dies are used to deform a tube workpiece. The second group is tube forming [10][11][12][13][14], in which only dies are used to deform a tube workpiece. The third group is sheet hydroforming [15,16], in which dies and/or hydraulic media are used to deform a sheet workpiece.…”

“…Kajikawa et al [10] proposed a tube expansion drawing method to effectively produce a thin-wall and large-diameter tube. Hirama et al [11] proposed a new ball spin forming equipment, which can form a reduced diameter section on the halfway point of a tube. The effects of forming process parameters on the surface integrity and deformation characteristics of the product were investigated.…”

“…Therefore, the demand for different diameter continuous tubes (DDC tubes) and the process for DDC tubes without joining processes is high. Hirama et al [11] proposed a new ball spin forming equipment, which can form a reduced diameter section on the halfway point of a tube. The effects of forming process parameters on the surface integrity and deformation characteristics of the product were investigated.…”