Machining performance enhancement of deep micro drilling using electrochemical discharge machining under magnetohydrodynamic effect

Abstract

Electrochemical discharge machining (ECDM) is a non-traditional machining technology used for micromachining of non-conductive materials including glass and ceramics. However, deep micro hole drilling (usually more than 500 μm) always encounters many problems, such as low repeatability, tool bending, and low machining efficiency. All these problems are mainly due to the bubble accumulation on the entrance hole. The phenomenon inhibits the electrolyte to enter the tip of the tool; therefore, the melting conditions will not be satisfied. The recent research shows that gas film formation and the motion of electrolyte are highly influenced by magnetohydrodynamic (MHD) effect. Further, the electrolyte circulation is improved by the MHD effect, and higher machining efficiency can be achieved. However, the poor electrolyte circulation in deep micro hole drilling is still exist, and the machining performance needs to be enhanced. In this paper, a simple, direct strategy for precisely tuning the machining parameters (i.e., supplied voltage and magnetic density) under MHD effect was introduced. Results show that the depth around 1000 μm can be achieved within 100 s with quite good surface quality and even deeper micro hole can be achieved. The method using MHD effect brings a great potential for the development of feedback control algorithms for micro hole machining.