微细电火花线切割加工表面摩擦性能的研究

Research on tribological properties of micro wire electrical discharge machining surface

微细电火花线切割加工技术已经成为加工微小复杂三维零件的重要加工方法,但是,对加工表面的摩擦磨损性能的研究很少.采用小于35μJ的微能量进行微细电火花线切割加工,结合放电机理和热力学传递过程,综合研究了微细电火花线切割加工表面在干摩擦条件下的摩擦磨损性能,并与超精磨削加工表面在同种条件下进行对比.结果表明,由于微细电火花线切割加工表面微观形貌的固有特征,使得微凸起减小了摩擦接触面积,微凹坑的容纳作用减少了摩擦表面之间的磨粒存留量,温升形成的氧化膜降低了微凸起接触界面的抗剪强度,并且摩擦过程由二体摩擦转变为三体摩擦,从而降低了摩擦系数,有效地减少了磨粒磨损和粘着磨损,摩擦学性能优于超精磨削加工表面.

The technique of micro wire electrical discharge machining （Micro-WEDM） has become an important method for the machining of 3D intricate micro parts. However, there is little research on tribological properties of the machining surface. In this paper, the micro energy of micro wire electrical discharge machining （ micro- WEDM） was lower than 35μJ. With the discharge mechanism and the thermodynamic transfer process, the tribo- logical wear properties of micro-WEDM surface were investigated under dry friction conditions. In addition, the mi- cro-WEDM surface was compared with superfine grinding machining surface under the same conditions. Results show that, because the micro-WEDM surface has its own microstructure characteristics, the micro-projections re- duced the friction contact area. Due to the containing of micro-concave pits, the quantity of abrasive particles re- maining on the friction surface was reduced. The oxidation film formed by increase in temperature reduced the shear strength of micro-projections contact interfaces, and the friction process transformed from two-body friction to three- body friction, so to reduce the friction coefficient, the abrasive wear and the adhesive wear were reduced. Therefore, the tribological performance of the micro-WEDM surface is superior to the superfine grinding machining surface.