Microcomputer-controlled polishing machine for very smooth and deep aspherical surfaces

The authors were required to fabricate small highly curved components with unusually deep asphericity together with extremely smooth and low damaged surfaces using lithium niobate, a crystalline material with anisotropic machining properties. Diamond-turning produced an accurate profile but with unacceptable roughness. Because existing CNC machines could not polish these surfaces adequately, a new polishing machine was developed. Three axes were controlled by a microcomputer to drive a very small rotating polishing tool over the rotating aspherical surface. The tool path was controlled to remove material uniformly from the surface or make corrections to surface profile.