Mitsui Seiki’s VGi20A Ball Screw Nut Grinding Multitasking Machine performs grinding and machining 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 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. 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 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 three-dimensionally-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 550mm, 600mm and 500mm respectively. A-axis trunnion movement ranges from +15˚ to -105˚, and C-axis rotation is 360˚. Maximum workpiece diameter is 250mm, height 300mm, and weight 120 kg. The machine spindle is capable of speeds from 15 rpm to 30,000 rpm and is fitted with an HSK-A63 taper. Tools up to 250mm in length and 90mm in diameter can be accommodated. Machine footprint is approximately 3200mm by 3000mm.
Bill Malanche, Mitsui Seiki USA chief operating officer, said, “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.”
Related Glossary Terms
Fluid that reduces temperature buildup at the tool/workpiece interface during machining. Normally takes the form of a liquid such as soluble or chemical mixtures (semisynthetic, synthetic) but can be pressurized air or other gas. Because of water’s ability to absorb great quantities of heat, it is widely used as a coolant and vehicle for various cutting compounds, with the water-to-compound ratio varying with the machining task. See cutting fluid; semisynthetic cutting fluid; soluble-oil cutting fluid; synthetic cutting fluid.
Machining operation in which material is removed from the workpiece by a powered abrasive wheel, stone, belt, paste, sheet, compound, slurry, etc. Takes various forms: surface grinding (creates flat and/or squared surfaces); cylindrical grinding (for external cylindrical and tapered shapes, fillets, undercuts, etc.); centerless grinding; chamfering; thread and form grinding; tool and cutter grinding; offhand grinding; lapping and polishing (grinding with extremely fine grits to create ultrasmooth surfaces); honing; and disc grinding.
- grinding wheel
Wheel formed from abrasive material mixed in a suitable matrix. Takes a variety of shapes but falls into two basic categories: one that cuts on its periphery, as in reciprocating grinding, and one that cuts on its side or face, as in tool and cutter grinding.
Process of generating a sufficient number of positioning commands for the servomotors driving the machine tool so the path of the tool closely approximates the ideal path. See CNC, computer numerical control; NC, numerical control.