What is Electrochemical Grinding?




Scientific and metallurgical developments have placed unusual demands on the metalworking industry. The challenges faced by industry are not only modern materials with high strength-to-weight ratios, but also with new fabrication requirements demanding greater precision and surface integrity.

Electrochemical Grinding Equipment (ECG) is an ideal machining process that provides a better, faster, and more cost effective metal cutting and grinding solution for today’s toughest materials. Unlike conventional grinding techniques, Electrochemical Grinding offers the ability to machine difficult materials independent of their hardness or strength. This is because Electrochemical Grinding is an entirely different machining process in which electrical energy combines with chemical energy for metal removal. Since Electrochemical Grinding Equipment does not rely solely on an abrasive process, the results are precise cuts free of heat, stress, burrs and mechanical distortions.

Electrochemical Reaction
Electrochemical oxidation and reduction occurs on the surface of electrodes when an electric current is passed between the electrodes through an electrolyte fluid. An electrochemical potential between the electrodes causes current to flow from the anode to the cathode in the DC circuit. In Electrochemical Grinding, the anode is the work piece, and the cathode is the conductive grinding wheel. A continuous stream of electrolyte flows at the interface of the grinding wheel and work piece and conducts the current in the circuit. The electrolyte fluid is a conductive aqueous solution consisting of a mixture of chemical salts and other additives. At the positive electrode, or anode, oxidation of the work piece dissolves the surface of the metal and forms a metal oxide film. The film is electrically insulating, and acts as a barrier against the electrochemical cutting action of the process

The abrasives in the rotating grinding wheel continually remove this film and expose a fresh surface for oxidation. Metal deposition on the grinding wheel (cathode) is avoided by proper choice of electrolyte. Dissolution of the metal, combined with the mechanical removal of the oxides, results in an efficient low-stress cut.

Electrical Energy
According to Faraday’s Laws the quantity of chemical change occurring at an electrode is directly proportional to the amount of current passing between the electrodes. Low voltage, high current electrical energy supplied by a properly designed DC power supply is central to the Electrochemical Grinding process. Since the voltages are low, spark discharge and the associated heat are avoided. In addition, the low voltages used prevent any electrical shock hazard to the operator.

Productivity Factors
With Electrochemical Grinding, the rate of metal removal is directly proportional to the current flowing across the contact surface between the wheel (cathode) and work piece (anode). The higher the amperage, the faster the rate of chemical change and stock removal. “Machinability” of a metal depends more upon its conductivity and electrochemical reactivity than its hardness or strength. Electrochemical Grinding Equipment can be used successfully on all electrochemically reactive and conductive materials.