Mill-turning up to one metre in diameter from Okuma

The mill-turn centre features 40 m/min rapid traverse in X, Y and Z axes, leading to short idle times, with the main and opposing 2,000 rpm spindles with C-axis and 142 mm diameter bore powered by 37/30 kW motors. Larger bore sizes of 185 mm and 275 mm are optional, in which case the 1,500 and 1,000 rpm spindles are driven by 45/37 kW motors. The Okuma Multus B750-Wx3000 utilises an automatic, 3-station changer above the counter-spindle / tailstock for long boring bars of up to 1.27 m. Normally, a machine would have to be stopped for bars of this length to be exchanged manually, reducing productivity. Another feature that characterises the B750 is Okuma's patented Thermo Friendly Concept, which is applied to both the machine structure and the spindle. Together with the use of 0.1 micron-resolution linear scales in the orthogonal axes, it compensates for the effects of ambient temperature variation of up to 8°C, limiting thermal deformation to less than 20 microns over a 24-hour period. The milling spindle swivels through +30 / -210 degrees in 0.001 degree increments. A multi-tool indexing function is available that enables up to six different turning inserts mounted on the same tool to be used. In place of a turning tool, the swivelling B-axis spindle accepts HSK-A100 (Capto C8 / BT50) tools, exchanged from a 40-station chain-type magazine (80 and 160 ATC are options), for carrying out heavy prismatic machining using up to 37 kW of power at 40 to 10,000 rpm. When designing this 40-tonne, 5-axis mill-turn centre, Okuma started with target applications in mind, namely one-hit production of parts for the oil industry and power generation sector, as well as, larger aerospace components.