Ultra machining carries the important mission of supporting more progress, and the need for strategic development and the attraction of the high profit market of ultra products has led to the development of ultra machining. Ultra-machining technology is to reduce the surface roughness of the workpiece, remove the damage layer, access and surface integrity of the processing means, at this stage, not to change the physical properties of the workpiece material for the premise of ultra-machining needs to make the shape of the workpiece accuracy and surface roughness to reach the sub-micron level, nanometer level, respectively, and even the pursuit of high surface integrity of the non-destructive polishing technology.

Complex surfaces are generally formed by the combination of surfaces with multiple curvatures to achieve certain mathematical characteristics, the pursuit of functional and aesthetic effects of the appearance of the form, including aspherical surfaces, free-form surfaces and shaped surfaces.