Horizontal-spindle machining centre for fully interpolative 5-axis CNC production

OKK’s HM-X6000 twin-pallet-change machine accommodates components up to 750 mm diameter by 700 mm high and weighing a maximum of 650 kg. It is the first 5-axis horizontal machining centre to be produced by OKK. Until now, the company has concentrated on 5-axis, vertical-spindle models and 4-axis horizontals. The Japanese machine builder chose a tilting trunnion/rotary table design rather than incorporating the rotary axes in the spindle head. In many 5-axis machines, says sole UK agent Whitehouse Machine Tools, while the linear axes may be fast and strong, the rotary axes tend to be weak links in terms of speed and rigidity. However, the HM-X6000, which uses double-disc clamping of the hydraulically counterbalanced, -110 / +20 degree swivelling trunnion (A-axis), generates a holding force of 10,000 N. A similar system on the 360-deg rotary table (C-axis) provides 6,800 N clamping force. As the pallet surface is 100 mm below the A-axis centre of rotation, the component sits more or less on the centreline, allowing maximum cutting force to be applied. Accuracy figures for positioning in A and C are an impressive ±5 and ±3 arc-seconds respectively. The HM-X6000 has a rapid traverse of 54 m/min and 10 m/min cutting feedrate in all three linear axes minimise machine idle time. So too does the two second exchange of a BT50 tool from the 40-station magazine (optionally up to 236 stations) to the 12,000 rpm, 30 kW, BIG Plus face-and-taper-contact spindle.