A recent spindle that runs on compressed air lets companies perform ultra high-speed and precision micromachining on existing machining centers. The RBX Air Power Spindle built by Big Daishowa Seiki Co. Ltd. in Japan and available from Big Kaiser Precision Tooling Inc. in Elk Grove Village, Ill., (bigkaiser.com) reduces machining time and extends tool life.

Kaiser says the RBX features ceramic ball bearings and excellent dynamic balance while exhibiting minimal thermal displacement. Cutting tools are clamped with a notch-free nut (tightened with a special wrench that comes with the spindle), to eliminate unbalance at high speed. The company says the spindle's air-turbine drive runs so quietly, workers can hear cutting noise from the micro tools.

The spindle comes in a RBX5 version, which operates at 30,000 to 50,000 rpm, and a RBX7 version. The latter operates at 60,000 to 80,000 rpm. Both versions have a 0.18 to 0.159-in. clamping range, a T.I.R. at the nose of less than 0.00004-in., and come in CAT, BBT, and HSK-A shanks. An optional stop block is available for the CATs and BBTs. Compressed air is supplied through the block, which allows for automatic tool changes.

The RBX can cut 0.0025-in. thick walls in aluminum and drill aluminum without a center drill. In one application, says Kaiser, even after drilling 3,500 holes, the cutting-tool edge showed no wear. In other jobs, a 0.004-in. ball-nose endmill in an RBX cut a complex, 2D shape on HRC40 tool steel in 120 min. at 80,000 rpm. This compares to 450 min. at 20,000 rpm on a machining center. And lastly, Kaiser reports that a 0.020-in. carbide drill in an RBX cut 1,200 holes at 50,000 rpm, whereas a drill on a machining center at 12,000 rpm produced only 500 holes.