Oblique/Curved Tube Necking Formed by Synchronous Multipass Spinning

Hirohiko Arai,Shiori Gondo

doi:10.3390/met10060733

Hirohiko Arai, Shiori Gondo

Open Access

https://doi.org/10.3390/met10060733

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Abstract

In this paper, we propose a method of forming a tube into an oblique/curved shape by synchronous multipass spinning, in which the forming roller reciprocates in the radial direction in synchrony with the rotation angle of the spindle while the roller moves back and forth along the workpiece in the axial direction to gradually deform a blank tube into a target shape. The target oblique/curved shape is expressed as a series of inclined circular cross sections. The contact position of the roller and the workpiece is calculated from the inclination angle, center coordinates, and diameter of the cross sections, considering the geometrical shape of the roller. The blank shape and the target shape are interpolated along normalized tool paths to generate the numerical control command of the roller. By this method, we experimentally formed aluminum tubes into curved shapes with various radii of curvature, and the forming accuracy, thickness distribution, and strain distribution are examined. We verified that the curved shapes with the target radii of curvature can be accurately realized.

Highlights

Metal spinning is a metal forming process in which a metal tube or sheet is rotated by a motor and pushed by a roller tool to form a target shape
The proposed searching algorithm can find the contact position between the roller and the the oblique/curved shapes expressed as a series of inclined circular cross sections with offset
Oblique/curved shapes expressed as a series of inclined circular cross sections with offset

Summary

Introduction

Metal spinning is a metal forming process in which a metal tube or sheet is rotated by a motor and pushed by a roller tool to form a target shape. Since the tooling cost of metal spinning is lower than that of press forming, it is effective for small-lot production of many kinds of custom-made products and for product prototyping. This process is applied to mass-produced parts and products such as automobile exhaust parts and stainless-steel bottles. It is advantageous for manufacturing large metal shells requiring a large die. If metal spinning can form noncircular shapes, which have been manufactured by press forming or sheet metal welding so far, the application of metal spinning will be further expanded

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