Research on feed-pulse collaborative control method in micro-electrical discharge machining

Abstract

Reducing the short-circuit rate and increasing the effective discharge rate are important targets for improving the servo control effect of micro-electrical discharge machining (micro-EDM), as these two indicators are closely related to the machining efficiency and quality. In this study, a feed-pulse collaborative control (FPCC) method is proposed for micro-EDM based on two dimensions (space and time). In the spatial dimension, a feed control strategy with a discharge holding process is adopted. Meanwhile, in the time dimension, a forward-looking pulse control strategy is adopted, in which the pulse interval is adjusted based on a sequence analysis of feed commands and discharge states. Process experiments are carried out to determine the key parameters used in this method, including the discharge holding threshold and pulse interval adjustment value ($T_{{\text{off}_{{\text{adj}}} }}$). The feed smoothness and discharge sufficiency analyses of the experimental results show that compared to the traditional double threshold average voltage method, the FPCC method reduces the number of long-distance retreats by 64% and improves the effective discharge time by 40%.

Keywords

Micro-electrical discharge machining (micro-EDM) / Electrode feed control / Discharge pulse control / Machining surface quality

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Funding

National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809(52075333); National Science and Technology Major Project http://dx.doi.org/10.13039/501100018537(2018ZX04005001)