Study of removing the recast layer by electrochemical dissolution with wire low feedrate in WEDM

One characteristic of WEDM surface is that it is covered with numerous craters and re-solidified materials, forming the recast layer which deteriorates the surface quality and other properties such as fatigue strength. In this research, a method combining WEDM and electrochemical dissolution together in a simple process is proposed and studied. The principle of the method is introduced. The recast layer can be dissolved and removed by electrochemical reaction with low wire feedrate in deionized water. The calculation model is established to find the suitable feedrate of the wire electrode, and the experiments are carried out to verify the proposed model. The calculation error of the model coming from the processing instability caused by the vibration of the wire is discussed. The stripes mainly composed of the re-solidified materials can be found on the surface when the high wire feedrate is used to cut the workpiece in WEDM. On the contrary, if the low feedrate is used, these stripes will disappear. If the feedrate further reduces, electrochemical dissolution can play the role to dissolve and remove the recast layer; the surface quality can be improved as a result. The influence of wire feedrate on surface topography and surface roughness is also analyzed.