Study On Multi-channel Discharge Atomization Ablation Machining Based On Discrete Electrode

The electrical discharge atomization ablation technology uses the large amount of chemical energy released by the combustion reaction between oxygen and the activated metal matrix which is induced by the spark discharge to remove the workpiece material,the processing efficiency of difficult-to-process materials is greatly improved.The ablation reaction energy is huge and there is only one discharge channel in a single discharge pulse to induce the metal matrix to be activated,the inducing energy and processing energy are concentrated.It is not conducive to controlling ablation reaction and improving processing surface quality.This paper proposes the multi-channel discharge atomization ablation processing technology based on discrete electrode.Multi-channel discharge induces metal matrix to be activated and forms multi-point ablation,which not only enlarges the scope of ablation reaction and enhances the efficiency of ablation processing,but also disperses the processing energy and improves the surface quality of workpiece.This technology provides a new means to realize high efficiency and high surface quality of workpiece in processing difficult-to-process materials.The main research work of this paper lists as follows:(1)The multi-channel discharge atomization ablation processing technology based on discrete electrode was proposed.The discrete electrode preparation process was realized.The multi-channel atomization ablation processing system was established,including improving machining experiment platform,designing workpiece rotation driving device,constructing gas-liquid atomization system and gas-liquid supply circulation system.(2)The multi-channel discharge mechanism of discrete electrode was analyzed.The equivalent circuit model of multi-channel discharge with discrete electrode and the theoretical model of the voltage U_n between electrode and workpiece and the total loop current I were developed.The single-pulse discharge comparison experiment was carried out.The result showed that there were four discharge pits after single-pulse discharge with discrete electrode.And the depth and diameter of each erosion crater were notably reduced.This indicated that multi-channel discharge can effectively disperse discharge energy.(3)The processing characteristics of multi-channel atomization ablation were studied and the multi-channel atomization ablation processing model was established.The processes are divided into three stages:multi-channel discharge ignition,multi-channel ablation,multi-point material removal and chip removal.The microscopic mechanism of each stage was also analyzed in the paper.In the macroscopic characteristic experiment,collecting discharge waveform and analyzing the discharge status between the electrode and workpiece.(4)The processing characteristics comparison experiment and research on technological rule of multi-channel atomization ablation were carried out.Using die steel Cr12 as workpiece,the results showed that the material erosion rate were improved by 92%compared with the single channel atomization ablation,4.12 times of multi-channel EDM,nearly 11 times as much as conventional single-channel EDM.And the multi-channel discharge machining not only reduced the relative loss of electrode volume,but also improved the quality of the machined surface compared with single-channel discharge machining.The influence of electrical parameters and non-electrical parameters on the machining characteristics of multi-channel atomization ablation were analyzed.