Effect of Process Velocityon Accuracy in Ultra-Precisi on Plane Honing
ZHANGYi5 GUOYinbiao6 SYOJI Katsuo7

Abstracts：In order to increase process accuracy and decrease wear of honing wheel，it is necessary to analyze the machining parameters of honing process．The machining locus of plane-honing wheel，radial honing wheel and spiral honing wheel on workpiece，and the slippage locus of workpiece on honing wheel are studied here．Also，the concepts of process accuracycoefficient and honing wheel wear coefficientrae presented here to describe the process accuracy and the wear degree of the honing wheel separately．Moreover，the correlative relationship between the machining parameters，the process accuracy and the Honing wheel wear has been established，and the influence of the above—mentioned on the process accuracy has been investigated．Emphasis is given to prove the effect of the relativevelocity between the honing wheel and the workpiece on the process accuracy．Through studying theoretically and effectively，there sults show that，by optimizing the structure of the honing wheel and adapting the appropriate machining parameters，the machining quality woud be improved and the wheel wear would be decreased effectively．
Keywords：Plane Honing；Process Parameters；Process Accuracy；Wear of Honing Wheel
 
    平面研磨技术已被广泛应用于超精密加工中，它可加工出粗糙度Ra为0.01—0.02μm的镜面。诸如量块、光学平面、集成电路的硅基片等硬脆零件，最后都是用超精密研磨与抛光得到要求的高质量表面。其关键是如何提高效率、加工精度，降低成本。采用超微粒金刚石砂轮的垂直布置的超精密平面研磨方法8,能满足上述需要。其结构如图1所示。

   平面研磨由于研磨轮和工件面接触，磨粒的有效切削数较多，可以得到高的表面精度及加工效率。同时，为了改善冷却液工作状态，减小加工动压的影响，现在研磨轮多数采用了开槽式结构设计二9。主要有：放射线沟槽结构和螺旋线沟槽结构两种形式。针对上述研磨方法，本文对此研磨过程的加工参数进行全面分析，得出微粒金刚石研磨轮的不同沟槽结构及加工速度变化对加工面精度的影响，并从理论上解决平面研磨中砂轮加工参数的选择问题。

1 平面研磨原理

   图1为超精密平面研磨的结构简图。机床砂轮和工件主轴采用气液混合轴承来消除加工中振动的影响，工件采用胶接或真空吸力固定在专用夹具上；工件主轴靠弹簧支撑在机床上，控制弹簧的伸缩长度可以实现对工件的恒压加工。在线修整机构可实现对加工用砂轮的修整闭1。
   平面研磨加工原理如图2所示。为了方便分析，图中设定：M为砂轮上一点；N为被加工工件上的一点，砂轮和工件的基本参数如图中所示。

   由图2所示砂轮与工件的运动关系，并通过坐标变换可得到砂轮上M点在工件上的加工轨迹方程为

   式中 θ—砂轮加工初始角
     ω1—工件的角速度
     ω2—砂轮的角速度
     α—砂轮和工件的中心距
     R—砂轮上M点的半径

   与砂轮的加工轨迹的求解相同，坐标系x’o2y’产上半径为r的N点在砂轮上的滑移轨迹方程为

   式中 φ—工件加工初始角
     ω1—工件的角速度
     ω2—研磨砂轮的角速度
     α—研磨砂轮和工件的中心距
      r—工件上N点的半径