切削液毛细管电动渗透机制研究

In this project, a novel electroosmosis mechanism of cutting fluids in machining interface capillaries is revealed and investigated to improve fluid penetrability, as well as enhance its lubrication and cooling effects during manufacturing processes. The increase of the capillary electroosmosis of cutting fluids at tool-chip interface leads to a significant improvement in the surface quality and tool life. This research project will first systematically understand the characteristics of tribo-potential/electron emission of friction fairs during friction processes. The formation mechanisms of tribo-electrostatic field and its effect on the fluid capillary electroosmosis on the rubbing interface will then be investigated. Based on tribological characterization and numerical analysis, the capillary electroosmosis mechanism of cutting fluids at the frictional interface will be revealed. Secondly, the project will establish a theoretical model of fluid penetration under capillary electroosmosis condition by systematically investigating the formation mechanism of capillary electroosmosis and its penetration process at the tool-chip interface. The role of capillary electroosmosis in improving fluid capillary penetration will be investigated by use of the developed model. Finally, the formula schemes of cutting fluids for improvement in the capillary electroosmosis will be investigated. The effect of fluid capillary electroosmosis on cutting processing characteristics including cutting forces, cutting temperatures, tool wear and surface integrity will be systematically compared and optimized under different cutting parameter conditions. Through the research of this project, a novel capillary electroosmosis machining technology will be achieved.

为了促进切削液在加工接触区的毛细渗透能力，增强切削液的润滑冷却效果，揭示并研究一种新的切削液毛细管电动渗透机制，通过调控刀/屑接触区切削液毛细管电动渗透，改善切削加工的质量和刀具使用寿命。首先，分析摩擦过程中摩擦副的摩擦电势和电子发射特性，研究摩擦界面毛细管电渗驱动电场的形成机理与调控机制，基于摩擦学性能和微流体电渗流场数值分析，研究摩擦界面的切削液毛细管电动渗透机理。其次，在研究切削条件下刀/屑接触区切削液毛细管电动渗透形成机制基础上，分析切削液渗透毛细管动力学过程，建立考虑电动渗透效应的切削液毛细渗透模型，研究促进切削液毛细渗透的电渗调控机制。最后，研究具有促进切削液毛细电渗性能的切削液配方，分析基于毛细电渗效应的切削加工工艺准则，对不同切削工艺参数下的切削力、切削温度、刀具磨损和加工表面完整性进行系统对比和优化，获得一种基于毛细管电动渗透效应的切削加工工艺技术。

切削液在刀/屑接触区的毛细渗透能够有效改善其冷却润滑性能。传统毛细渗透润滑理论表明切削液在刀/屑界面的毛细渗透主要受大气压力、水头压力以及毛细力影响。在高效液相色谱及电渗泵领域，可通过电渗流的形式调控毛细通道内的流体。受刀/屑摩擦界面摩擦电势、摩擦电子发射等摩擦电学现象引起的自激发电场启发，本项目提出了一种考虑切削加工区水基切削液电动渗透效应的新型渗透理论，并开展了针对切削加工中切削液电渗调控方法的理论和实验研究。主要研究有：设计开发了球-盘摩擦工况与车削工况下的摩擦电势和摩擦电子发射检测平台，分析了摩擦过程中摩擦副的摩擦电势和电子发射特性，研究了摩擦界面切削液毛细电渗驱动电场的形成机理与调控机制。研究表明，通过材料摩擦荷电形成的自激发电场能够加速界面空间低能电子撞击空气分子，诱发电子雪崩和摩擦等离子体。摩擦自激发电场沿界面毛细管的轴向分量及气体放电形成的空间电荷能够以电渗流的方式驱动润滑液渗透。建立了切削液毛细电动渗透实验平台以及平流式流动电位测量系统，分析了摩擦副材料在不同切削液中的荷电情况，掌握了切削液毛细电渗特性的调控机制。研究表明，添加电渗调控剂和调节切削液pH值可通过改变刀具/切削液、工件/切削液界面双电层结构调控切削液的毛细电渗特性。分析了切削液渗透刀/屑接触区毛细管动力学过程，提出了切削液毛细电渗模型和有利于促进电渗的切削液配方，开展了基于切削液毛细电渗效应的切削加工验证。研究表明，适当调节切削液电渗特性可提高接触区切削液毛细渗透能力，充分发挥切削液的润滑冷却潜能。与基础切削液的车削加工比较，采用考虑毛细电渗效应的切削液，切削力减小26%左右，工件表面粗糙度Ra值减小27%左右。基于切削液毛细电渗的切削技术在传统渗透模型基础上引入加工区自激发电场对切削液的电驱动效应，完善了切削液的毛细渗透理论，提高了切削液的使用效率，对实现我国绿色制造发展战略具有重要意义。