Because in the conventional machining fluid such as cutting oil and grinding fluid contained several chemicals, enormous disposal cost and environmental load is occurred. Therefore in this investigation, electric rust preventive machining method which uses only water for machining fluid is developed. Because using only water without extreme pressure agents, oil and so on, this method saves much work in a disposal of used machining fluid. In this paper, supporting electrode (anode) is developed to prevent effectively rust generation of workpiece and electro-magnetic chuck and the optimized rust prevention current was verified. As a result, rust prevention of workpiece and electro-magnetic chuck when use supporting electrode of noncontact type is achieved by very low current of 0.1A (6.8V: 0.68W, one workpiece, 1 hour), 0.2A (10V: 2W, two workpieces, 1 hour). Moreover, the supporting electrode of two types is developed, and the characteristics were compared.
