The manufacture precision of super exactitude NC lathe depends on not only the operation rate of NC deviceand joined precision, but also the error of track and point location about servo system.

Experimental results show that higher efficiency can be accomplished and bigger layer thickness and bigger servo feed rate can be chosen in UED-Milling in gas with the aid of ultrasonic vibration.

Both the simulation and experimental results indicate that the dual flapper-nozzle servo valve has good flow-current characteristics and strong ability to control small flow rate.