A New Relay Based Control Model for Vertical Axis Falling Problem of CNC Machine during Power Failure

In this paper, a new relay-based control model, called as RCM has been proposed for the CNC machine used in the industry to resist the vertical axis falling problem during power failure. The proposed RCM is an electronic design mainly composed by a solid-state electronic relay and a circuit breaker. Such electronic relay directly operated from phase line. Including some modification of the software, this additional circuit is placed on the z-axis of the clutch type servo-motor. The advantages of this control model are straightforward, faster in operation, and less-expensive for implementation. In order to evaluate the proposed control model, a number of experiments were conducted. In the experimental testing, we have shown the amount of axis fall down with and without RCM. It is clearly found the amount is within 0.01~0.03mm which will not affect the output job. For VMC, it is very good in accuracy. The experimental results showed that the axis fall down problem of CNC machine was minimized with providing around 99% accuracy while the power is off. Not only that no hamper was made for job during experiment including no breakage of tools or, cutter of the CNC machine although power failure was made artificially.