1984 - An array of components each of 5mm x 3.5mm are ground to light-band flatness by this 7 axis grinding machine. Size control is to within 0.5µm with chamfers parallel to better than 0.1µm. All three high stiffness aerostatic grinding spindles carry cup wheels which are cooled and lubricated with through wheel coolant. The work pieces are held in 150mm square sets on a stiff air-bearing table. The machine was used in production at IBM, Rochester Minnesota, to manufacture the ferite "flying heads" or "sliders" for magnetic memory disks. It is the consistent surface finish of the workpiece which made this machine so valuable in production. Each component had a short wavelength 20nm Ra surface integrity free from grinding damage.
1987 - Built as a calibration angle standard, this machine represented the ultimate in rotary position control. The main spindle is built on an externally pressured air bearing to ensure that both radial and axial error motions are below the microinch (25nm) level. The spindle, which carries 400 nm platern, is controlled by a direct drive dc torque motor & tacho with an integral coplaner coupling to the angular transducer. The position transducer is a CUPE glass grating with 8 fringe doubling, dc reading heads. The internal operating resolution is 0.0024 arc secs which with digital error compensation gives better than 0.1 arc sec pk-pk accuracy.« Back Next »