Working fluid that contains oil, lubricant agent, and antirust agent is generally used in the cutting and grinding processes, and water is never used in these two processes to prevent rust. Naohiro Nishikawa, an Iwate University assistant professor, developed a system that allows for the machining process using water in place of working fluid. Because the system uses only water, it does not need time-consuming treatment of the working fluid. Used water can be reused after purification treatment.
The system immerses a workpiece and the working machine in water, connects them electrically from without, and processes them as if they are two electrodes. Water used in the process cannot be used without treatment because it contains abrasive grains and iron ion. The system has a built-in purification unit composed of filter and reverse osmosis membrane. It can treat 10 liters of used water per minute. Although the newly developed system is lower in performance than the system using working fluid, it can improve productivity because it does not need the process to eliminate working fluid. It can save more than 100 billion yen to dispose of water oil that amounts to 800,000-900,000 kiloliters annually and prevent carbon dioxide emissions that amount to 1,500,000 tons annually.