Patent ID: 7105956

Claim:
A high precision z-theta stage having a horizontal translation axis (z-axis) and a rotary axis (theta-axis) parallel with the translation axis for machining a cylindrical workpiece comprising: a base plate having upper surfaces lying in a plane; parallel spaced apart linear translation stages each having parallel linear bearings with bearing surfaces mounted at a substantially equal distance from the planar surfaces of the base plate, each linear translation stage having a brushless linear motor; a carriage supported between the parallel translation stages by the linear bearings; and a rotation stage carried by the carriage between the parallel translation stages, said rotation stage comprising a brushless rotary motor having a shaft journaled with an axis parallel to the linear bearings, the carriage and rotation stage having a vertical and a horizontal center of gravity, said rotary motor being hollow to accommodate the cylindrical workpiece, each brushless linear motor being connected to the carriage to apply translation forces in a horizontal plane intersecting said vertical center of gravity.