In the recent machining, using the machining fluid that is contained EP additive, oil and rust preventive agent is disposed after used. This waste fluid is applied to incineration and reclamation or coagulative precipitation. As a result, huge disposal cost and environmental load is occurred. In this investigation, electric rust preventive machining method that is using only harmless water as machining fluid is developed for reducing effluent treatment. This method is prevented to rust of workpiece by supplying the slight electric current for cathode workpiece. However, this method has problem that is machine body corrosion. Therefore, coating machine body and applied the electric rust prevention is examined. And rust prevention of electro-magnetic chuck's bare metal surface that is difficult to coating is achieved 3 hours.
