薄板与模具接触条件对微成形摩擦行为影响研究

发布时间：2018-04-28 08:30

本文选题：薄板微成形 + 摩擦尺寸效应　；参考：《哈尔滨工业大学》2011年硕士论文

【摘要】：微成形中摩擦尺寸效应的存在,给微成形加工工艺带来许多不利影响。本文针对薄板微成形摩擦尺寸效应进行了系统研究,构建了考虑尺寸效应的理论模型,揭示了摩擦尺寸效应产生机理;基于DLC薄膜,进行了金箔微筒形件拉深实验,并分析了DLC薄膜的磨损性能。通过滑动实验对不同尺寸的T2紫铜薄板在液体润滑的条件下进行摩擦系数的测量,研究了接触条件对摩擦系数的影响规律。结果表明,摩擦尺寸效应即摩擦系数随试样尺寸减小而增加的幅度随实际接触面积比例的增加而增大;随模具表面粗糙度的增加而减小;随正压力的增加而略有减小;随滑动速度的增加而略有减小。基于库伦定律,考虑液体润滑和非润滑区域比例,建立了考虑尺寸效应的薄板微成形摩擦模型,分析表明,随着尺度系数的减小真实接触面积增加,从而出现摩擦尺寸效应现象;基于Wanheim/Bay通用摩擦模型对所建立的理论计算模型修正,将其应用到体积成形过程中。基于所建立的考虑尺寸效应的薄板微成形摩擦模型,采用Abaqus有限元软件,实现微成形过程的数值模拟计算。通过对不同尺度系数下的微拉深过程的数值模拟计算表明,尺度系数较小时由于摩擦较大,容易出现拉深破裂现象。利用在表面制备DLC薄膜的落料拉深复合模具进行了T2紫铜箔和金箔微筒形件拉深成形实验,并以PE薄膜润滑作为对比,研究了不同润滑条件对微筒形件表面质量、成形精度和拉深成形力的影响。并利用AFM和Raman光谱对DLC薄膜的磨损进行机理分析,结果表明在磨损过程中DLC薄膜发生相转变和氢含量的升高。
[Abstract]:The existence of friction size effect in micro forming has brought many adverse effects to micro forming process. In this paper, the friction dimension effect of thin plate microforming is studied systematically, the theoretical model considering dimension effect is constructed, the mechanism of friction dimension effect is revealed, and the drawing experiment of gold foil microcylinder part is carried out based on DLC thin film. The wear properties of DLC films were analyzed. The friction coefficient of T2 copper sheet with different sizes under liquid lubrication was measured by sliding experiment, and the influence of contact conditions on friction coefficient was studied. The results show that the friction size effect, that is, the friction coefficient increases with the increase of the actual contact area ratio, decreases with the increase of the surface roughness of the die, and decreases slightly with the increase of the positive pressure. It decreases slightly with the increase of sliding velocity. Based on Coulomb's law and considering the ratio of liquid lubrication to non-lubricating region, the friction model of thin plate microforming considering size effect is established. The analysis shows that the real contact area increases with the decrease of scale coefficient. Based on the Wanheim/Bay general friction model, the theoretical calculation model is modified and applied to the bulk forming process. Based on the friction model of thin plate microforming considering size effect, the numerical simulation of micro-forming process is realized by using Abaqus finite element software. The numerical simulation of the micro-drawing process under different scale coefficients shows that the small scale coefficient is easy to appear the phenomenon of deep drawing fracture because of the large friction. The drawing experiments of T2 purple copper foil and gold foil microcylindrical parts were carried out by using the blanking and drawing compound die with DLC thin film on the surface. The surface quality of the microcylindrical parts under different lubrication conditions was studied by using PE film lubrication as a comparison. The influence of forming precision and drawing forming force. The wear mechanism of DLC thin films was analyzed by AFM and Raman spectra. The results showed that the phase transition and the increase of hydrogen content occurred in DLC films.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH117.1

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