磁流变变间隙动压平坦化加工力特性研究

Study on the Polishing Forces Characteristics of Magnetorheological Variable Gap Dynamic Pressure Polishing

磁流变变间隙动压平坦化加工利用工件的轴向低频振动使磁流变液产生挤压强化效应,可以有效提高加工效果并使光电晶片快速获得纳米级表面粗糙度。通过旋转式测力仪试验研究不同变间隙参数对磁流变变间隙动压平坦化加工过程中抛光正压力的影响规律,结果表明,在工件轴向低频振动作用下,抛光正压力形成脉冲正值和负值周期性的动态变化过程;将工件轴向低频振动过程分解为下压过程与拉升过程,下压速度和拉升速度对动态抛光力有不同的响应特性;随着最小加工间隙的减小抛光正压力会急剧增大;设置最小加工间隙停留时间观察抛光正压力变化,可以发现在工件最小加工间隙停留期间抛光力从峰值逐渐衰减并趋于平稳;挤压振动幅值对抛光正压力影响较小。建立了磁流变变间隙动压平坦化加工材料去除模型,弄清了在动态压力作用下,磨料更新及其附加运动机制,研究了磁流变变间隙动压平坦化加工过程中磨料颗粒对工件表面柔性划擦和微量去除的作用机理,为磁流变变间隙动压平坦化加工的工艺优化提供了理论依据。

Magnetorheological variable gap dynamic pressure polishing uses the axial low-frequency vibration of the workpiece to produce the extrusion strengthening effect of magnetorheological fluid,which can effectively improve the processing effect and make the photoelectric wafer quickly obtain nano surface roughness.The influence of different variable gap parameters on polishing pressure in magnetorheological variable gap dynamic pressure polishing process is studied by rotating dynamometer test.The results show that the polishing pressure changes periodically under the axial low-frequency vibration of the workpiece;The axial low-frequency vibration process of the workpiece can be divided into pressing process and pulling process.The pressing speed and the pulling speed have different response characteristics to the dynamic polishing force.The polishing pressure increases sharply with the decrease of the minimum machining clearance.When the minimum clearance residence time was set to observe the change of polishing pressure,it was found that the polishing force gradually weakened from the peak value and stabilized during the minimum clearance residence.The vibration amplitude has little effect on the pressure of polishing.A material removal model is established for magnetorheological variable gap dynamic pressure polishing,and the mechanism of abrasive regeneration and additional movement under the action of dynamic pressure was clarified.The mechanism of flexible scratching and micro removal of abrasive particles on workpiece surface during magnetorheological gap dynamic pressure polishing is studied,which provides a theoretical basis for the process optimization of magnetorheological variable gap dynamic pressure polishing.