Acoustic emission investigations into electrical discharge machining

电火花加工(EDM)是一种精密的材料去除工艺，它利用刀具和工件之间快速(~20-100 kHz)火花放电产生的热量，通过填充介质液体的小间隙将其隔开。一次放电需要4个不同的阶段：(1)在工具和工件之间施加电压，(2)导致等离子体形成的介电击穿，(3)在刀具和工件之间放电导致电流流动，导致刀具和工件都熔化和汽化，以及(4)等离子体通道内爆，将材料从熔池中喷射出来，随后冲刷和固化熔融颗粒。上述缝隙现象涉及的物理现象相当复杂，目前还不太清楚。在这种背景下，拟议的研究计划寻求开发一种简单但新颖的方法来研究电火花加工中的声发射(AE)。

Electrical discharge machining (EDM) is a precision material removal process that utilizes the heat generated from rapid (~20-100 kHz) spark discharges between the tool and the workpiece that are separated by a small gap filled with a dielectric fluid. A single discharge entails 4 distinct stages: (1) application of a voltage between the tool and the workpiece, (2) dielectric breakdown leading to plasma formation, (3) discharge between the tool and the workpiece leading to the flow of a current resulting in melting and vaporization of both the tool and the workpiece, and (4) implosion of the plasma channel that ejects material off the molten pool, followed by flushing and solidification of the molten particles. The physics involved in the gap phenomena above are rather complex and currently not well understood. In this context, the proposed research program seeks to develop a simple but novel approach to investigate acoustic emission (AE) in EDM.