Plasma CVM is an ultraprecision machining method using the chemical reaction between neutral radicals generated in the plasma and atoms on the work surface. The high-density plasma is generated under an extremely high-pressure atmosphere (1atm). The neutral radicals generated in the plasma react with surface atoms and transform them into volatile molecules. Then, atoms on the work surface are vaporized and removed. Not only does plasma CVM not disturb the atomic arrangements of the work surface, but it also combines extremely high machining efficiency and figuring performance equal to those of conventional mechanical machining. Consequently, plasma CVM is evaluated as a new high-efficiency, damage-free machining method, which may replace conventional mechanical machining.

In atmospheric-pressure plasma, the plasma is localized, since the mean free path of the gas molecule is small. To date, various types of machining equipment such as those for numerically controlled machining, cutting, and polishing have been developed.

The figure below shows an example of the machining of a plane mirror for synchrotron radiation. The left shows the shape before machining, and the right shows the shape after machining. Although the plane before machining is polished to the limit in conventional mechanical machining, the figure error of 158nm(p-v) remains in area of 320mm×40mm. Using numerically controlled plasma CVM, the figure error was corrected to 22.5nm.