【作者】 钱双庆；

【导师】 朱荻；

【作者基本信息】 南京航空航天大学 ， 机械制造及其自动化， 2011， 博士

【摘要】 研究表明,表面织构技术是改善摩擦副表面摩擦学特性的有效手段。目前,表面织构已经在缸套、滑动轴承和机械密封等工程技术领域中获得了成功的应用。因此,低成本、高效率、高精度的表面织构加工技术已成为制造领域的研究热点。国内外研究学者提出了多种表面织构加工手段。电解加工(Electrochemical Machining, ECM)具有诸多优点,如:与工件材料的硬度无关,加工表面无热影响层等,因此,该技术引起了研究人员的关注。电解加工是利用工件阳极在电解液中发生阳极溶解的原理,将工件加工成形的一种制造技术。由于电解加工过程中,工件材料的减少过程以离子的形式进行,因此这种溶解去除方式使电解加工技术在微细制造领域有着巨大的发展潜力。本文主要针对特征尺度为数十微米至数百微米的金属表面织构加工技术,提出了表面织构电解加工技术。根据工具阴极与工件阳极的相对位置不同,本文提出了活动模板电解加工技术和电解转印技术。本文的主要内容包括以下几个方面:(1)提出全新的活动模板电解加工表面织构技术。该技术可以有效降低加工成本,提高加工效率和加工柔性。(2)建立活动模板电解加工表面织构的极间电场模型。利用有限元技术分析加工定域性,并对加工过程进行模拟,将数值分析及模拟结果用于指导试验研究。(3)开展活动模板电解加工表面织构技术研究。构建活动模板电解加工平面和曲面织构试验系统,研究了活动模板结构尺寸对表面织构形貌的影响。分析了表面织构随加工过程参数的变化,如电流密度,加工时间等。同时,试验研究了不同阳极工件材料加工后的表面织构形貌。(4)提出采用辅助阳极来提高活动模板电解加工技术的定域性,通过电场理论分析比较了无辅助阳极和有辅助阳极时工件阳极表面的电场分布规律,并通过试验验证辅助阳极可以有效地提高活动模板电解加工的定域性。(5)开展电解转印表面织构技术研究。试验研究了基于金属基底的SU-8光刻胶紫外光刻工艺的各个环节,利用优化的工艺措施,制备了高尺寸精度、轮廓清晰、无明显缺陷、与基底金属结合力强的工具阴极。基于电场模型分析工具阴极上胶膜尺寸及加工间隙对加工定域性的影响。同时,研究加工电源对表面织构形貌的影响。(6)考察研究表面织构技术对缸套-活塞环/活塞摩擦副摩擦学性能的影响,选择合适的活塞环/活塞片断作为试件,并采用活动模板电解技术在活塞环/活塞表面加工不同尺寸的表面织构。在往复式摩擦试验机上进行摩擦试验,试验结果表明,合理的活塞/活塞环表面织构具有良好的抗磨减摩效果。更多还原

【Abstract】 It has been identified that the surface texture can improve tribological property. At present, it has been widely applied to many fields such as cylinder, journal bearing, and mechanical seal. Therefore, the processing of surface texturing with low cost, high efficiency and accuracy has become a research topic.Various techniques about surface texturing are employed. Compared to the other processing methods, electrochemical machining (ECM) is popular for its advantages in many applications such as its regardless of material hardness and no heat affected layer. ECM is a process of the anodic electrochemical dissolution of the metallic materials in an electrolytic medium utilizing the electrochemical reaction. Due to the tiny size of metal ion, ECM has a tremendous potential in the micro-manufacturing field.To fabricate well-defined surface texture in tens of microns to hundreds of microns, electrochemical micromachining of surface texturing is presented. According to the relative position of the tool cathode, the new technology can be classified as through movable mask electrochemical machining and electrochemical pattern transfer, and relative research has been carried out. The dissertation consists of several sections:(1) Through movable mask electrochemical machining of surface texturing is proposed. Compared with the traditional through mask electrochemical machining(TMEMM), the modified TMEMM can reduce cost,improve machining efficiency and flexibility .(2) The model of current distribution between the anode and cathode through the electrochemical machining process is build. Finite Element Method is then used to solve the model. The machining localization is analyzed and numerical simulation is carried out for better understanding the process and obtaining good processing parameters.(3) The key factors influencing the electrochemical machining of surface texturing process through movable mask have been studied experimentally. The experimental system of electrochemical machining is developed. The effects of the dimension of the movable mask and the machining parameters such as current density and the machining time on the surface texturing are investigated experimentally. The appearance of the surface texturing on different anode material surfaces are generated.(4) The auxiliary anode is consisted in the mask of the modified TMEMM to improve the localization of the surface texture. Numerical simulation of the current density in the interelectrode gap is verified the proposed method theoretically and the effect of the auxiliary anode on the machining localization on the aluminum-alloy surface is investigated experimentally. The experimental results indicate that the machining localization is significantly improved by the auxiliary anode successfully.(5) The key factors influencing the electrochemical pattern transfer of surface texturing have been studied theoretically and experimentally. The parameters of UV lithography process have been studied to pattern SU-8 photoresist spincoated on the cathode surface. Using optimized process parameters, some SU-8 moulds with good definition and topography, fewer defects and excellent adhesion to the metal substrate have been generated successfully. The mathematical model in the interelectrode gap is carried out and the influence of different interelectrode gaps on the electric field distribution is analyzed by the finite element method. The effects of the interelectrode gap and the pulse power parameters on the etch factor of the micro-dimple are investigated.(6) To verify the effect of surface texturing on the piston/piston ring samples, the friction tests are carried out using a reciprocating friction tester. According to the contact between the piston/piston rings and cylinder liner, friction tests are carried out for a variety of surface texture with different density and dimensions. The results of friction experiments show that the friction coefficient of the surface with appropriate surface texture is obviously lower than that smooth surface.更多还原