Mitsubishi Heavy Industries, Ltd. (MHI) has completed development of the “Mitsubishi Super Skiving System” for machining internal gears with high-speed precision.

This new system overcomes technical issues characteristic of conventional skiving by use of an MHI-developed, barrel-shaped, multiple cutting-edge rotary tool, enabling mass production of internal gears. In addition, longer tool life and shorter machining times will enable reductions in production costs. MHI is aiming to commence marketing of the new tool and skiving machine in April of 2015.

The “Super Skiving Cutter” was designed by applying skiving technology to MHI's barrel-shaped grinding wheel, developed for MHI's ZI20A gear- grinding machine, a machine designed for mass-production applications in 2009.

Skiving is a cutting technology whereby a pinion type cutter or other rotary tool is engaged with a workpiece at a crossed-axes angle, and synchronously rotated together. At the points where the two contact, the effect of the crossed-axes angle generates a sliding velocity of the tool in the axial direction, resulting in high-speed machining. Use of a pinion cutter-type tool, however, typically makes the cutting (skiving) angle obtuse – a drawback that impedes improvements in cutting precision and also causes significant tool wear.

With MHI's newly developed tool, the adoption of a barrel shape averts interference with the workpiece and prevents the cutting angle from becoming obtuse. As a result, a large crossed-axes angle can be achieved, enabling the realization of cutting speeds and precision levels surpassing those of pinion-cutter type skiving.

The new MHI ‘Super Skiving System’ was first exhibited at the 27th Japan International Machine Tool Fair (JIMTOF) held at Tokyo Big Sight from Oct. 30 through Nov. 4.