Effect of Electrolytes on Surface Integrity in Electrochemical Honing Process

Abstract

Electrochemical Honing (ECH) is a process of precision finishing of functionalsurfaces with the use of the electrical and mechanical energy. It is reported that the90 percent of the material is removed by electrochemical machining (ECM) process andremaining 10 percent by mechanical scrubbing, which shows the electrical energy is the mainconstituent in the ECH process. Basically, electrical energy is combined with chemical toform an etching reaction to remove material from the workpiece surface. The electrolyte ispumped through the gap between the tool (cathode) and the workpiece (anode) while acontinuous DC current is passed through the cell at a low voltage, so as to dissolve metalfrom the workpiece. Electrolytes are substances that become ions in solution and acquire thecapacity to conduct electricity. The electrolyte has three main functions in the electrochemicalmachining (ECM) zone. It carries the current between the tool and the workpiece, it removesthe product of the reaction from the cutting region, and it removes the heat producedby the current flow in the operation. Electrolytes must have high conductivity, low toxicityand corrosivity, and chemical and electrochemical stability. The rate of material removal inECM is governed by Faraday’s laws and is function of current density. Primary variablesthat affect the current density and MRR are voltage, feed rate, electrolyte conductivity,electrolyte concentration/composition, electrolyte flow rate and material of the workpiece.Therefore, electrolyte must be selected carefully for better outc