A compact five-axis machining centre suited to machining highly complex components has been introduced by Yuasa Warwick Machinery. The Ohtori Kiko OSU-545 is a high accuracy design 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.

This isolates all linear movements (500 mm in X, 400 mm in Y and 400 mm in Z) above the machining area, greatly reducing 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 rev/min equivalent, while the C-axis can position at 25 rev/min.

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 6,000 rev/min but a 120 to 12,000 rev/min option is available.

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

Maximum tool weight is 6 kg.

Control is by the Fanuc System 15M.

Standard format is three interpolating axes plus two positional, but full five axis control is available as an option.