多次切割电极丝在流体中动态特性研究

Dynamic characteristics of multi-cutting electrode wire in fluids

为了研究多次切割电极丝的动态特性,首先对电极丝在电介质流体中的受力情况进行了分析,建立起多次切割电极丝的空间力学模型,并通过加入电极丝平面振动引起的附加轴向力,建立了流固耦合非线性平面振动模型,然后采用四阶Runge-Kutta法求解出电极丝中心质点的运动轨迹。在此基础上,分析出单边放电导致电极丝振动偏移是造成实际修正量减小的直接原因。根据Einstein两相流体粘度理论,得到了废屑粒子容积浓度和两相流体阻力系数之间关系。数值计算结果显示,电介质流体速度对电极丝动态影响显著,甚至会出现颤振失稳现象。最后讨论了各参数对加工精度的影响机理。

In order to study the dynamic characteristics of multi-cutting electrode wire, its spatial mechanical model was established by analyzing the stress condition of electrode wire in the dielectric fluid, and a fluid-solid coupling nonlinear vibration model was established by joining the additional axial force on wire electrode, caused by wire vibration, and the fourth order Runge-Kutta method was employed to obtain the motion trajectory of electrode wire center. On this basis, the conclusion is obtained that the direct cause of actual reducing of the rectified quantity is the electrode wire migration caused by unilateral discharge. According to Einstein two phase fluid viscosity theory, the relationship between the scrap particle volume concentration and two phase fluid drag coefficient was clarified. Simulation results show that the velocity of dielectric fluid is of great dynamic effect on electrode wire, and even may cause flutter instability phenomenon. The influences of machining parameters on the machining precision were discussed.