Aerotech Inc.’s ABS series direct-drive air-bearing spindles provide accurate angular positioning and velocity control for disk-drive testing, imaging and precision wafer inspection. The ABS2000 is balanced to ISO 1940 G 0.4 tolerances and uses labyrinth-type sealing to minimize particle migration from the spindle, resulting in certification for Class 1 cleanroom operation. An integral rotary union acts as the vacuum supply. The motor produces continuous torque with negligible losses, eliminating the need for cooling fins or external cooling. Velocity ripple is <0.1%, asynchronous error motion is <20 nm, and total error motion is <100 nm. The motor and rotary encoder are coupled to a common shaft.