A Study of Influence of Servo-Control Strategy on Machining Efficiency in Micro-EDM

Abstract

Micro-electrical discharge machining (micro-EDM) is a non-contact manufacturing technology that is based upon the erosion effect of a spark. It is a significant method for machining hard-to-cut materials and fabricating micro-scale structures. However, the traditional servo-control strategy, which is widely used in micro-EDM, tends to make the process unstable due to the tiny pulse discharge energy, high pulse discharge frequency, and complex discharge state. As a result, the effective discharge ratio and processing efficiency are low, which increases the cost and so limits the application of this technology. To solve this problem, a simulation model is established in this paper to analyze the negative influence on machining efficiency by traditional servo-control strategy. Then, a self-adaptive servo-control strategy is proposed to adjust the feed speed to match up with the actual material removal rate. Simulation and experimental studies are undertaken to verify the effectiveness and validity of the proposed strategy. The results demonstrate that feed speed can converge gradually under the self-adaptive servo-control strategy and the effective discharge ratio and processing efficiency are significantly improved.