The Niigata HN80D HMC machines medium to large parts in a wide range of materials with traverse rates of 1,181 ipm and feed rates of 592 ipm on the box ways. Full 50-hp cuts are achieved through an advanced two-range geared headstock. With only three rotating components, maximum power is transmitted to the cutting tool. Large diameter ballscrews, coupled directly to AC digital servomotors, provide high-thrust drilling. The HMC’s spindles are built to be rigid and rapid. A large spindle diameter and a single-piece, snout-type head design ensure heavier milling capability and greater accuracy as compared to traditional bolt-together type spindle head designs, the company says.
Other features include box ways with hand-scraped mating members; massive columns and bed-type (triangular rib structure) construction. The bed-type design is said to provide full support over the entire X-axis travel, eliminating the possibility of overhang weakness. According to the company, the Y-axis double guide system results in enhanced stability and ensures maximum rigidity and improved contouring capabilities.
The HMC also incorporates a spindle chiller unit that removes excess heat from the spindle and bearing housing. Oil temperature is controlled by a sensor in the machine base that adjusts the lubricating oil temperature relative to the machine’s thermal characteristics. In addition, the stand-alone ATC does not transfer vibration to the spindle during tool selection. The spindle bearings are constantly lubricated using an oil injection system, which is intended to maximize bearing life and minimize preventative maintenance downtime. Other design features include an automatic rotary-type pallet changer; a Fanuc CNC control; a variety of built-in diagnostic features; accessible service points; and more.