基于定长补偿的微细电火花三维型腔加工方法

The Method of 3D Micro EDM Milling Strategy Based on Fix-length Compensation

电火花铣削可利用简单电极以逐层扫掠的方式有效加工复杂三维型腔。采用定长补偿方法配合电极旋转进行电火花铣削加工,电极端面会形成圆锥形,经过两刀铣削加工后第一层的加工面会呈现波浪形。针对波浪面对加工精度的影响进行了仿真分析,结果表明波浪面对最终的型腔底面形状几乎不产生影响。为获取最佳一层表面以减小对后续加工影响,确定了第一层第二步加工的最佳深度的定义;并通过三角形假设和正弦曲线假设从几何上找到了最佳深度的取值范围。通过实验验证了理论模型并进一步细化最佳深度取值区间,为后续精确加工奠定了基础。

EDM milling has irreplaceable advantages in fabricating complex three-dimensional cavity with simple electrode scanning layer by layer. By adopting the method of fix-length compensation with electrode rotating, the end face of the electrode will gradually become conical and the machined surface of the workpiece will appear wavy after first layer machining. A simulation is conducted to reveal the effect on machining accuracy caused by the wavy surface. Results show that the wave in the cavity bottom has almost no impact on further processing. A concept of optimum depth in first layer second step is defined to minimize the impact on the subsequent processing,by means of the triangle hypothesis and sine curve hypothesis ,the interval of the optimum depth value is found out geometrically. The theoretical model is verified by experiment and the interval of the optimum depth is further refined, establishing a solid foundation for further machining of more complex and accurate cavity.