Mori Seiki’s NT series of integrated mill-turn centers fully combines a lathe with a machining center. The NT5400 DCG/1800S employs both driven at the center of gravity (DCG) technology and the box-in-box construction of the NH series HMCs. The center also employs a turret with a built-in milling motor from the NL series CNC lathes.
The center features a subspindle, allowing for high speed and high-precision continuous machining. The machine’s maximum turning length is 70.8". The mill-turn center is in the 15" chuck size class and commands a maximum bar work diameter of 4.1".
The B axis uses a direct-drive motor, virtually eliminating backlash and making high-speed rotation possible. Indexing specifications for the axis cater to high precision machining requirements, the company says, allowing for input by units of 0.0001 degree.
For maximum efficiency and productivity, the machine’s maximum tool spindle speed is 8,000 min-1 with a maximum spindle speed of 2,400 min-1. Additionally, the machine’s ATC features a tool-to-tool change time of 1 second. This model features a tool magazine that stores a standard number of 20 tools, in addition to a 40-tool and 60-tool option, for as many as 100 tools.
Special attention to thermal displacement allows machines in the series to perform at high levels of accuracy and precision, the company says. The lower turret is located symmetrically in relation to the center of the spindle, forming a construction that is said to be resistant to the effects of heat. Additionally, ballscrew and motor-jacket cooling have been implemented to completely eradicate inaccuracy caused by heat variations.