三轴离子束抛光系统驻留时间算法

Dwell time algorithm for the 3-axis ion beam figuring system

在光学离子束抛光工艺中,驻留时间求解是一个关键问题。多数驻留时间求解算法要求离子束在工件表面的材料去除速率在加工过程中保持不变。然而,离子束在工件表面的材料去除速率与离子束入射角度有关。为此,在加工曲面工件时,通常采用精密五轴联动运动平台对离子源的运动及姿态进行实时控制,使得在加工曲面工件时离子束相对工件表面的入射角度始终保持不变,从而保证去除函数在整个离子束抛光过程中保持不变。提出了一种基于仿真加工的迭代驻留时间求解算法,在求解驻留时间的过程中考虑到入射角度带来的去除速率变化,从而使得在离子束抛光系统中只需采用三轴运动控制平台对离子源的运动进行控制,而不再需要对离子源的姿态进行实时控制。入射角度与去除速率曲线可以事先通过实验测得。与五轴运动平台相比,三轴平台更稳定、经济且易于控制。仿真结果表明,算法在三轴离子束抛光系统中具有较好的适用性。

The dwell time solution is a key problem in the ion beam figuring process. Most dwell time solution algorithms require that the material removal rate in the ion beam figuring process should be kept constant. However, the material removal rate on the workpiece of the ion beam is usually related to the incident angle of the ion beam. To overcome this problem, the ion source is usually controlled by a 5- axis motion system to keep the incident angle constant towards the surface of the workpiece when figuring a curve surface. An iteration dwell time algorithm based on simulation machining was proposed. Due to the influence of the incident angle of the ion beam, only a 3-axis motion system will be required to control the motion of the ion source and doesn＇t need to control the posture of the ion source in real time. The variable beam removal function in the ion beam figuring process can be predicted according to the material removal property of the ion beam on the curved surface by experiments before the figuring process. Compared with the 5-axis system, the 3-axis system has many advantages such as cheaper, more stable, easier to control and so on. The simulation results show that the dwell time algorithm is suitable for the dwell time solution of the 3-axis ion beam figuring system.