Paterning of Micro Indents by Electro-Chemical Jet Machining

本文提出了一种利用有限元法计算电解液中电势分布的数值方法来分析电解液射流加工（ECJM）的加工形状。在该电解液加工中，高压电解液从精密喷嘴喷射，喷嘴的位置对工件进行数控，并在工作间隙中提供脉动加工电流，用于微细加工。首先，假设电解液中存在电压降，通过对工件表面电位分布得到的电流密度进行积分计算理论加工电流。其次，调整假设的电压降，使理论加工电流与测量的加工电流一致。然后，使用校正后的电压降重新计算工件表面上的电流密度分布。最后，通过测量电流密度与材料去除率之间的关系，得到工件的等效洗脱价和电流效率，从电流密度分布中得到加工形状。数值计算得到的形状与实验结果吻合较好。

The present research proposes a numerical method to analyze the machined shape in the Electro-Chemical Jet Machining (ECJM) by calculating the ditribution of electric potential in the electrolyte using the Finite Element Method (FEM). In this ECJM, a high pressure electrolyte is jetted from a fine nozzle whose position is numerically controlled against the workpiece, and a pulsating machining current is supplied in the working gap for micro-fabrication.At first, assuming the voltage drop in the electolyte the theoretical machining current is calculated by means of integrating the current density, which can be obtained from the potential distribution, over the surface of the workpiece. Secondary, the assumed voltage drop is adjusted so that the theoretical machining current should coincide with the measured machining current. Then, the current density distribution over the surface of the workpiece is recalculated using the corrected voltage drop. Lastly, from the current density distribution the machined shape is found by taking the equivalent elution valence of the workpiece and the current efficiency, both of which are obtained from the measured relationship between the current density and the material removal rate, into account. It was found that the shape obtained by the numerical calculation coincided well with the experimental result.