For "HS-WEDM" cutting, there is no special requirement for the preparation of the working liquid, as long as it is not hard water or groundwater; for "MS-WEDM" cutting, owing to consider trim cuts with smaller energy, the standard of water quality could be lightly higher. When the efficiency is reduced evidently, the trim cut is not continuous, or the surface after trim cuts is not bright, attention should be paid to water quality, this is why the majority of "MS-WEDM" machine tool manufacturers advise users to use the purified water to compound the working liquid in order to avoid such problems.

       Similarly, because the water quality varies from place to place, JiaRun working liquid may produce some foam in the processing, it is suggested that the operator may add a few drops of kerosene to eliminate the foam.