Professional Instruments Company first attached motors to air bearing spindles in the late 1960s. Since then we have motorized thousands of spindles. Drive systems of almost every imaginable type have been implemented. Friction devices, belt drive, timing belts, couplings, and integral motors are used to drive the 300 spindles in our shops. This vast experience and our ability to analyze spindle errors provide us with significant insights into motor drive technologies.
Integral motorization delivers the best combination of properties for ultra-high-precision rotary motion. We start by buying custom motors from manufacturers who understand our specific needs. Motion Control Systems, Shin Maywa, and Inland supply motors to the majority of our customer applications. To control the air gaps, we purchase motor rotors and stators with excess stock on the inside and outside diameters, allowing us to control the interfaces. We install non-magnetic containment rings on all of our high-speed spindle motor rotors. Internal cooling channels in our motor housings provide for precise management of the heat from the motor windings. Motor commutation in our brushless-DC motorized spindles is handled using hall cells, wire-wound resolvers, or glass-disk encoders. We apply encoders from manufacturers including Heidenhain, Sony, and MicroE. Our AC induction motor spindles are capable of being powered directly by line current, making them completely free from drive-induced noise. Brush-style DC motors used in combination with glass-disk encoders and brush tachometers represent the ultimate in high-torque servo control. The high-resolution encoder provides position feedback while the tachometer monitors velocity. Professional Instruments Company’s air bearing servo pivot assemblies achieve remarkable position control while maintaining unmatched error motion.
Professional Instruments Company’s brushless-DC motorized air bearing spindles are being used in the world’s finest aspheric generators. We have thoroughly tested these spindles and proven radial and axial synchronous errors under one-millionth of an inch and asynchronous errors under one-tenth of a millionth of an inch. No one in the air bearing business tests their spindles to the level we do. The attention to detail included in our motorized packages makes Professional Instruments Company spindles an incredible value.