Ball Screw Nut Grinding Multitasking Machine Cuts Nut Processing Time By Two-Thirds

Mitsui Seiki’s VGi20A ball screw nut grinding multitasking machine performs grinding and machining in one chucking, slashing nut processing time by two-thirds, says the company. The combination of grinding, multitask machining and automation strategies gives the machine its true advantage. With five axes of motion and storage for 40 tools, the machine can grind thread grooves and also machine the nut circumference, end surface, key grooves and return tube holes in a single setup. In addition to producing large savings in manufacturing time, elimination of setup changeovers also assures exact phase alignment of thread grooves and return tube holes. The machine also produces threads via simultaneous interpolation of the C-, Y- and Z-axes.

A standard touch probe further enables automatic pre-processing phase alignment of the thread groove and wheel. Users can generate optimal grinding programs automatically by entering data on the grinding screen of the machine’s FANUC 31i-B5 control. 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 3D-designed automatic coolant nozzle changer provides coolant to an optimal point based on the profile of the workpiece, grinding wheel and quill.

X-, Y- and Z-axis strokes of the VGi20A are 550 mm, 600 mm and 500 mm respectively. A-axis trunnion movement ranges from +15º to -105º, and C-axis rotation is 360º. Maximum workpiece diameter is 250 mm, with a height of  300 mm, and a weight of 120 kg. The machine spindle is capable of speeds from 15-30,000 rpm and is fitted with an HSK-A63 taper. Tools up to 250 mm in length and 90 mm in diameter can be accommodated. Machine footprint is approximately 3200 mm x 3000 mm.