A compact, five-axis machining centre suited to producing highly complex components to close tolerances has been introduced by Yuasa Warwick Machinery. The Ohtori Kiko OSU-545 is capable of linear accuracy better than +/-4 microns with repeatability of +/-2 microns. Out-of-roundness on circular interpolation of 3 microns can be achieved, making the machine eminently suitable for top-precision, five-axis work such as turbine rotor machining from solid material.

The design is unusual in that it adopts a gantry format for machining over a work envelope of less than half a metre cube.

Installed weight is 8.5 tonnes - twice what one would expect of a 500 mm3 machining centre.

All linear movements (500 mm in X, 400 mm in Y and 400 mm in Z) are isolated above the machining area, greatly reducing the risk of swarf and coolant ingress into the slides; and aiding thermal stability.

Moreover, the layout provides a high degree of mechanical rigidity.

A massive cast A-axis trunnion supports the rotary C-axis / worktable assembly to provide angular positioning.

A-axis tilt of + 120 degrees and - 90 degrees can be programmed in 0.001 degree increments, as can the 360 degree C-axis.

All axes are driven by digital AC servo drives, utilising twin Y-axis ballscrews to eliminate skew.

Rapid traverse speeds are 20 m/min in X and Y, and 16m/min in Z.

A-axis positioning speed is 15 rpm equivalent, while the C-axis can position at 25 rpm.

The tee-slotted worktable measures 400 mm by 500 mm and can accommodate workpieces up to 230 kg weight and 240 mm maximum height.

Minimum linear programmable increment is one micron.

An external chiller optimises thermal stability of the 7.5 kW machining spindle, whilst symmetrical mounting of the spindle evens out heat distribution.

Standard speeds are in the range 60 to 10,000 rpm.

Spindle taper is BT40 with either 30, 40 or 60 tools available in the tool changer.