HMC Uses Precision, Power, and Torque to Boost Productivity
The HU63EX horizontal machining center from Mitsui Seiki USA, Inc. (Franklin Lakes, NJ) is engineered to boost metalworking productivity through a combination of precision, power, and torque. The 17,000 kg (37,400 lb) machine has a footprint of 2,900 mm (116 in) x 3,180 mm (127 in), with X, Y and Z axes travels of 900 mm, 800 mm and 800 mm (36 in, 32 in and 32 in) respectively.
The machine’s structure maximizes rigidity and accuracy. The bed is a single casting supported at three points, which minimizes the effect of foundation fluctuations on accuracy. A thickened structure and specifically-developed rib configuration generate high rigidity.
The mating surface of each axis box way, as well as other important areas such as rotary axis mounting, ball screw mounting points and spindle attachment surfaces are carefully hand-scraped, establishing extremely precise geometric characteristics such as parallelism, squareness, and straightness. This ensures consistent accuracy over an extended period of time.
Air cavities between the ways and the column mating surfaces are charged with low-pressure air, reducing the load on the way surface and enabling smooth movement without compromising rigidity.
An overview of the manufacturing expertise and capabilities used by Mitsui Seiki in their machine tool construction.
Ball screws located at the center of each guide way also assure stable movement. Mitsui Seiki says the machine offers X, Y and Z axis positioning and repeatability accuracy of ±0.001 mm (±0.00004 in or one micron), and B axis (rotating the 630 mm [25.2 in]-sq pallet) accuracy of ±2 sec with repeatability ±1 second.
The focus on accuracy and rigidity produces repeatable precision performance. According to Mitsui Seiki, in turn-boring operations on 10 consecutive workpieces the HU63EX achieves concentricity within three microns. In addition to precision, the HU63EX offers substantial power and torque.
The machine’s standard 50 taper 6,000 rpm spindle offers 18.5/15 kw (30 min/continuous, 24.7/20 hp) power with 601 nm (443 ft-lb) torque, delivered through a two-step gearbox. Optional spindles include a 6,000 rpm, 26 kw/22 kw (34.8/29.4 hp) unit with 1,081nm (797 ft-lb) torque and a three-step gearbox, and a 12,000 rpm, 30 kw/25 kw (40/33.5 hp) version with 420 nm (309 ft-lb) torque driven by an integral, built-in motor.
