Advanced Metal Spinning: Internal Metal Shear Forming and Expanding
In contradiction to traditional metal shear forming (described above), the metal in internal metal shear forming is worked into a concave chuck arrangement. Rather than starting from the centre of the spun metal and working out, the process is reversed. The sine law applies to this too.
Internal metal shear forming is often combined with multi-pass expanding with the flow of sequence being the same in multi-pass metal spinning, although reversed in relation to the axis of rotation. Internal metal spinning requires a sizeable hole in the centre of the blank. Contrasting to traditional metal spinning, the metal is tangentially under tension which prevents any buckling, so the process is only limited by metal strength. This technique is popular by metal spinners for use on large-diameter, thin-walled parts.
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