The G4-Ultra machine from Atometric is an example of a commercially available machining center designed specifically for micromachining. With a work cube of about 4 inches, the machine is available with a 100,000-rpm air-cooled or 200,000-rpm water-cooled spindle.
The machine is smaller and faster than more conventional machining center designs that realize micromachining. However, it is also limited to micromachining. The spindle cannot accommodate tools with conventional shank sizes.
Linear motors in three axes provide acceleration better than 2G. Linear scale feedback with 5-nanometer resolution allows the machine to achieve sub-micron repeatability at the tool tip, as opposed to only along individual axes. By means of a rotary table, the machine can be configured for three-, four- or five-axis machining.