颗粒增强铝基复合材料的多边形中空电极电火花打孔实验研究

发布时间：2018-03-07 07:35

本文选题：电火花加工　切入点：颗粒铝基复合材料　出处：《广东工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：电火花加工颗粒增强铝基复合材料(AMCs)是一种非常有前景的加工方法,可以避免传统刀具破损,降低加工成本,但是电火花加工AMCs也存在自身的缺陷,这些问题主要是由PRAMCs材料中的增强颗粒带来的,增强颗粒通常是电绝缘材料,而且他们的熔点和汽点等物理特性是合金的几倍高,在电火花加工的时候,增强颗粒难以融化,因此加工过程中,这些增强颗粒对金属融化起到阻碍作用,加工效率与增强颗粒分数成反比。而且随着加工深度的增加,加工效率会变更差,而蚀除微粒也会引起二次放电现象的产生,使加工过程不稳定。而且随着电火花加工小孔深径比的增大,这些现象对加工的影响也将增大。本论文探索异形电极加工PRAMCs材料,研究了Al2O3颗粒铝基复合材料多边形中空电极电火花打孔的实验效果,来验证多边形中空电极对加工环境的改善,提高电火花对颗粒增强铝基复合材料打孔效率的影响。首先,本文理论分析了电火花加工颗粒增强铝基复合材料的蚀除机理和加工影响因素;其次,本文对多边形中空电极加工铝基复合材料加工间隙流的场进行建模与仿真,分析多边形中空电极间隙流场分布和间隙蚀除微粒分布情况;然后,本文通过单因素实验、正交实验和响应曲面法考察峰值电流、脉宽、占空比、主轴转速、冲液压力等因素对多边形中空电极加工Al2O3颗粒铝基复合材料的材料去除率、工具损耗速度、工具相对损耗的影响,并与圆形中空电极进行对比,结果显示相同加工工艺下,多边形中空电极的材料去除率更好,工具损耗速度也更高,但是工具相对损耗更小。论文对比了圆形中空电极和多边形中空电极深孔加工效果,实验显示多边形电极深孔加工材料去除率更好,但加工表面粗糙度更大。本文通过对多边形中空电极和圆形中空电极加工孔壁的扫描电镜图片,对比分析了多边形中空电极的电火花蚀除情况,表明多边形中空电极加工更剧烈,单个脉冲能量效率更大,间接验证了多边形中空电极排屑效果的改善。
[Abstract]:EDM particle reinforced aluminum matrix composites (EDM) is a promising machining method, which can avoid the breakage of traditional cutting tools and reduce the machining cost. However, EDM AMCs also has its own defects. These problems are mainly caused by reinforced particles in PRAMCs materials, which are usually electrical insulating materials, and their physical properties such as melting point and vapor point are several times higher than those of alloys, and it is difficult for the reinforced particles to melt during EDM. Therefore, in the process of processing, these reinforced particles hinder the melting of the metal, and the processing efficiency is inversely proportional to the fraction of the enhanced particles, and as the processing depth increases, the processing efficiency becomes worse. Moreover, with the increase of the ratio of depth to diameter of small hole in EDM, the effect of these phenomena on machining will also increase. In this paper, special electrodes are used to process PRAMCs materials. The experimental results of polygonal hollow electrode (EDM) drilling of Al2O3 particle aluminum matrix composite were studied to verify the improvement of machining environment and the effect of EDM on the perforation efficiency of particle reinforced aluminum matrix composite. In this paper, the mechanism of EDM particle reinforced aluminum matrix composites and the influencing factors are analyzed theoretically. Secondly, the machining gap flow field of polygonal hollow electrode processing aluminum matrix composites is modeled and simulated. The distribution of gap flow field and clearance erosion particles of polygon hollow electrode is analyzed, and the peak current, pulse width, duty cycle, spindle speed are investigated by single factor experiment, orthogonal experiment and response surface method. The effects of pressure on the material removal rate, tool loss speed and tool relative loss of polygonal hollow electrode processing Al2O3 particle aluminum matrix composite are compared with those of circular hollow electrode. The results show that the material removal rate, the tool loss rate and the relative loss of the tool are compared with the circular hollow electrode, and the results show that under the same processing technology, The polygonal hollow electrode has better material removal rate and higher tool loss speed, but the tool loss is smaller. The paper compares the deep hole machining effect between circular hollow electrode and polygonal hollow electrode. The experiment shows that the material removal rate of polygon electrode deep hole machining is better, but the machined surface roughness is larger. In this paper, the scanning electron microscope pictures of polygonal hollow electrode and circular hollow electrode are used to process the hole wall. The EDM erosion of polygon hollow electrode is compared and analyzed. The results show that the polygon hollow electrode is processed more intensively and the energy efficiency of single pulse is greater, which indirectly verifies the improvement of chip removal effect of polygon hollow electrode.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG661

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