ABSTRACT

In the Electrochemical discharge machining (ECDM) process, the geometry and quality of the desired feature mainly depend on the thickness and structure of the gas film over the tool electrode, respectively. In order to machine various arbitrary-shaped profiles, control over the gas film shape is necessary for the ECDM process. The present research work deals with controlling the gas film shape by controlling the applied electrostatic force acting on the gas bubbles during the machining process. This was achieved by maintaining an appropriate inter-electrode gap (IEG) and applied energy. A mathematical model was drawn to establish the relationship between IEG, applied energy, and electrostatic force. Based on the magnitude of electrostatic force acting on gas bubbles, IEG was divided into two zones by considering the effect of the sphere of influence on the gas bubble. High-speed images and experimental evidence were used to validate the mathematical model. Hole over the cut (HOC), hole deviation, and hole depth was considered as output characteristics. An elliptical hole with a hole deviation of 60.08%, HOC of 75 mm, and 420 µm hole depth was achieved. With the optimal parametric setting at various counter electrode positions, elliptical holes of different orientations were fabricated.

摘要

在电化学放电加工（ECDM）过程中，所需特征的几何形状和质量分别主要取决于工具电极上方的气膜厚度和结构。为了加工各种任意形状的轮廓，对于ECDM工艺，必须控制气膜形状。本研究工作通过控制在加工过程中作用在气泡上的静电力来控制气膜形状。这是通过保持适当的电极间间隙（IEG）和施加的能量来实现的。绘制了数学模型以建立IEG，施加的能量和静电力之间的关系。根据作用在气泡上的静电力的大小，考虑到影响范围对气泡的影响，IEG分为两个区域。高速图像和实验证据被用来验证数学模型。切口上的孔（HOC），孔偏差和孔深度被视为输出特性。获得了椭圆形孔，其孔偏差为60.08％，HOC为75 mm，孔深为420 µm。通过在不同对电极位置的最佳参数设置，可以制造出不同方向的椭圆孔。