In traditional electrical discharge machining (EDM) of micro-holes, the debris removal becomes increasingly challenging as hole depth increases, significantly affecting the machining of difficult-to-machine materials. To address this issue,we first developed a micro-hole gap flow field model for a novel longitudinal–torsional ultrasonic vibration (LTV) electrode EDM drilling method. We analyzed the effects of three types of electrodes — rotation electrodes, longitudinal ultrasonic vibration (LUV) electrodes, and LTV electrodes — on the flow velocity in the micro-hole interstitial flow field. Next, we simulated the motion of fluid and debris in the interstitial flow field of micro-holes, theoretically verifying the advantage of electrode ultrasonic vibration in enhancing debris removal efficiency. Additionally, we observed the electrode tip morphology, the elemental composition on the electrode surface, and the morphology of the micro-hole inlet/outlet and inner wall to further elucidate the debris removal mechanism and confirm the superior drilling performance of the ultrasonic vibration electrodes. At an optimal ultrasonic amplitude (m), the LUV electrode demonstrated improved consistency in the micro-hole inlet/outlet and achieved a micro-hole taper of 0.014°. The material removal rate (MRR) using the LTV electrode reached 5.14 × 10m/s, nearly 1.5 times higher rotation electrode. This method successfully produced a positively tapered hole suitable for injector nozzles.

中文翻译：

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研究超声波振动辅助电火花加工钻孔中的碎屑去除机制


在传统的微孔放电加工（EDM）中，随着孔深度的增加，清除碎屑变得越来越困难，显着影响难加工材料的加工。为了解决这个问题，我们首先为新型纵向扭转超声振动（LTV）电极电火花加工方法开发了微孔间隙流场模型。我们分析了三种类型的电极——旋转电极、纵向超声振动（LUV）电极和LTV电极——对微孔间隙流场中流速的影响。接下来，我们模拟了微孔间隙流场中流体和碎屑的运动，从理论上验证了电极超声振动在增强碎屑去除效率方面的优势。此外，我们还观察了电极尖端形貌、电极表面的元素组成以及微孔入口/出口和内壁的形貌，以进一步阐明碎屑清除机制并证实超声振动电极的优越钻孔性能。在最佳超声波振幅 (m) 下，LUV 电极表现出改善的微孔入口/出口一致性，并实现了 0.014° 的微孔锥度。使用LTV电极的材料去除率（MRR）达到5.14×10m/s，几乎是旋转电极的1.5倍。该方法成功地生产了适用于喷油器喷嘴的正锥度孔。