超声切削加工中的动压油膜模型建立及其试验研究

Hydrodynamic Pressure Oil Film Modeling and Experimental Study of Ultrasonic Vibration Cutting

根据超声切削过程的运动特性和冷却液作用特征,基于流体动压理论,建立刀具与工件之间动压油膜的模型。分析前刀面油膜压力的变化规律、分布状态和试验的工艺效果,证明超声切削过程可以产生高冲击动压的油膜,油膜压力的作用可使切屑产生弹性变形甚至是挤压变形和剪切滑移。超声振动切削过程会形成油膜作用和刀具接触切削两个阶段,油膜的作用可以增大剪切角,使刀具锐化并改变刀具前刀面与切屑的接触状态,提高加工的表面质量。讨论了油膜状态和切削液粘度对加工效果的影响。

On the basis of kinetic characteristic of ultrasonic vibration cutting and the action feature of coolant, the model of hydrodynamic pressure oil film between tool and workpiece is built on the basis of hydrodynamic pressure theory. Through analyzing the variation regularity and distribution state of hydrodynamic oil film pressure on rake face and the process effect of machining experiment, it is proved that high hydrodynamic pressure oil film can be produced in ultrasonic vibration cutting. And the chip can be caused elastic deformation, even extrusion deformation and shear slippage by hydrodynamic pressure of oil film. The process of ultrasonic vibration cutting has two phases, i.e. oil film action and tool contacting with chip. Action of oil film can increase shear angle, make tool sharpened and change contacting state between rake face and chip, and improve the surface quality of workpiece. The influences of the oil film state and the coolant viscosity on the machining result are discussed.