Abstract: Adopting single factor method, Experimental studies on electrical discharge machining in gas (dry EDM) are carried out to realize the effect of basic operating parameters (such as electrical parameters, gap voltage, etc.) on machining performance. Experimental results indicate that it is suitable for workpiece use as anode and tool electrode as cathode. It is observed that the material remove rate (MRR) and surface roughness (SR) increase with the increase of pulse duration and peak current, and decrease with the increase of pulse interval in the range of the experimental data . It is found that the MRR is increase and SR improve when a suitable capacitance is parallel connected with tool electrode and workpiece; and the reasons producing the phenomena are analyzed. For a given parameters, there is an optimal gap voltage at which better machining performance can be obtained. Better machining characteristic of dry EDM can be achieved with higher tool electrode rotate speed. Analyzed the machining performance of different gas media on base of physical characteristics of different gases media and found that the MRR machining in oxygen medium is the highest. It is found that surface micro-rigidity ED machining in air higher than that of base material and lower than that of ED machining in kerosene.

Key words: EDM, EDM in gas, Machining performance, Arc-shaped fame, Friction torque, Precision assembly, Seeker, Servo mechanism