电渗效应对水基切削液在刀-屑界面渗透润滑影响机理的实验研究

Experimental Study on Influence Mechanism of Electroosmotic Effect on the Penetration and Lubrication of Water-based Cutting Fluid at Tool-chip Interface

切削区毛细管润滑理论在解释切削液刀-屑界面渗透发挥润滑作用时主要考虑大气压力和毛细力,未关注切削区荷电粒子发射所引起的切削液电动效应。切削区电学效应所产生的电场足以诱发切削液产生电渗流。基于此,首次探究了电渗效应对水基切削液渗透机理的影响,揭示了电渗添加剂、毛细管材料和轴向电场对切削液电渗特性的影响规律。通过测量切削区间隙中的荷电粒子发射强度,掌握了切削区毛细管两端自激轴向电场的变化特性。结果表明,切削液在切削区存在电渗效应且与工件材料和荷电粒子发射强度相关。车削AISI 304不锈钢时,电渗促进型切削液润滑下的切削力相比于纯去离子水和电渗抑制型切削液润滑时分别降低了31.1%和44.3%。刀具刃口的扫描电子显微镜(Scanning electron microscopy,SEM)和能谱分析(Energy dispersive spectroscopy,EDS)显示,随切削液电渗性能提高,切削刃的磨损形式由粘附磨损转变为微崩刃,表明电渗效应与切削液的渗透及切削性能呈正相关。研究结果对于了解电渗效应对切削液渗透机理的影响,完善毛细润滑理论,以及最终提高切削液使用效率有重要参考价值。

The micro-capillary lubrication theory explained lubricant penetration into the tool-chip interface under the action of atmospheric pressure and capillary force without considering the electrokinetic effect caused by triboelectrification.The axial electric field generated by the electrical effect in the cutting contact zone was enough to trigger the electroosmotic flow of cutting fluid.Based on this,the effect of electroosmosis on the penetration mechanism of water-based cutting fluid was explored for the first time,and the effects of electroosmosis additives,capillary materials and axial electric field on the electroosmosis characteristics of cutting fluid were also revealed.The variation of self-excited axial electric field at both ends of capillary in cutting zone was investigated by measuring the emission intensity of charged particles.The results showed that the cutting fluid has electroosmosis effect in the cutting zone,which related to the property of workpiece material and the emission intensity of charged particle.Compared with pure deionized water and electroosmotic suppressant cutting fluid,the cutting force lubricated with electroosmotic promoter cutting fluid was reduced by 31.1%and 44.3%respectively when cutting AISI 304.Moreover,the scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)analyses on the tool edges using the above fluids showed a transfer from adhesive wear to micro breakage,which demonstrated that the electroosmosis effect has a positive relationship with the penetration of cutting fluid and the cutting performance.The results presented in this study are of great significance for understanding electroosmosis effect on the lubricant penetration mechanism to perfect the micro-capillary lubrication theory and provide reference for improving the efficiency of cutting fluid.