用于电火花加工抬刀运动的速度规划算法

A Jump Motion Velocity Planning Algorithm Using for Electro-discharge Machining

电火花加工时,通过采用周期性的抬刀运动来降低放电间隙中的蚀除物浓度,能在改进有效放电率的同时提高加工的稳定性。目前用于电火花加工抬刀运动的速度规划算法,如常数加加速度S形曲线速度规划,其加加速度变化是不连续的,常数加加速度由于阶跃变化会引起机床的冲击和振动,使放电间隙状态变得不稳定,从而导致加工的不稳定。提出了一种用于抬刀运动的连续加加速度的速度规划算法,根据抬刀最大速度、抬刀高度及机床Z轴允许的最大加加速度进行基于连续加加速度的速度规划。通过对该速度规划算法进行的加工比较验证实验可知,运用该速度规划方法可在保证加工效率的基础上,更好地减少对机床的冲击和振动,使加工过程更稳定。

In order to improve the effective discharge ratio and the machining stability in electrodischarge machining（EDM）,a periodic jump motion of the electrode can be adopted so as to reduce the debris concentration in the discharge gap. Velocity planning is an important part in the design of a jump motion. However,existing velocity planning algorithms,such as the S-shaped feedrate planning,do not address the discontinuities in jerks. With a possibility of invoking vibrations in a machine,discontinuities in jerks are harmful to a stable discharge status. A velocity planning algorithm with continuous jerks for jump motion is proposed,which takes into considerations constraints on the maximum velocity,jump heights and jerks of the Z-axis of a machine. The experimental results show that this proposed velocity planning algorithm achieves a better performance with a smoother jump motion and the stability and reliability is verified through an EDM machining for a deep slot.