Vertical Machining Centers For Slanted Hole Machining

With tilted spindles that allow the use of shorter tools, Makino’s line of Variable Geometry (VG) horizontal machining centers (MCC-VG Series) are useful for simultaneous three-axis and slanted hole machining of large dies and molds. The tilted spindle prevents the spindle and tool from colliding with the table. This design also allows continuous machining of slanted holes at various angles without changing the setup. In addition, the company says its custom through-coolant spindle technology flushes out chips to enhance the speed and accuracy of drilling angled holes.

 

To eliminate the need to measure tool length each time the spindle is indexed, the machines are equipped with the company’s custom tool tip position calculation function. This measures a calibration value in advance for every tilt angle of the spindle, then corrects the tool tip position automatically after indexing. It also automatically applies compensation for spindle thermal distortion in three dimensions as machining proceeds, resulting in a step between machined surfaces within 3 micrometers. 

 

The spindle speed is 12,000 min-1, taper hole is 7/24 taper No. 50 and the spindle drive motor is 18.5/11 kW (40 percent ED/cont). The spindle is supported by cylindrical roller bearings, each with an inner diameter of 11 mm. The company’s custom spindle-core cooling system circulates temperature-controlled cooling oil through the center of the rotating spindle to cool it directly from the inside.