Mitsui Seiki VGi20A Grinding Machine Speeds Nut Processing

Mitsui Seiki’s VGi20A Ball Screw Nut Grinding Multitasking Machine grinds and machines in one chucking, slashing nut processing time by two-thirds. With five axes of motion and storage for 40 tools, the machine can grind thread grooves and machine the nut circumference, end surface, key grooves and return tube holes in one setup. In addition to saving manufacturing time, eliminating setup changeovers assures phase alignment of thread grooves and return tube holes. A standard touch probe enables automatic pre-processing phase alignment of the thread groove and wheel.

The machine produces threads via simultaneous interpolation of the C-, Y- and Z-axes. Users can enter data on the FANUC 31i-B5 control’s grinding screen to automatically generate optimized grinding programs. Canned measurement cycles are available for setup. A rotating dresser shapes wheels for grinding thread profiles, and a single-point dresser prepares wheels for grinding nut circumferences and end surfaces. An optional automatic coolant nozzle changer provides coolant to an optimal point based on the profile of the workpiece, grinding wheel and quill.

The VGi20A’s X-, Y- and Z-axis strokes are 550 mm, 600 mm and 500 mm respectively. A-axis trunnion movement ranges from +15 degrees to -105 degrees, with 360-degree C-axis rotation. The machine fits workpieces with diameters up to 250 mm, heights up to 300 mm and weights up to 120 kg. The machine spindle is capable of speeds from 15 rpm to 30,000 rpm and is fitted with an HSK-A63 taper. It accommodates tools up to 250 mm in length and 90 mm in diameter, with a Machine footprint approximately 3,200 x 3,000 mm.

“By combining grinding, multitask machining, and automation strategies, the VGi20A represents an integrated ball screw nut processing center that minimizes production time while simultaneously maximizing accuracy and repeatability,” says Bill Malanche, Mitsui Seiki USA’s chief operating officer.