【作者】 缪东辉；

【导师】 高长水；

【作者基本信息】 南京航空航天大学 ， 机械制造及其自动化， 2010， 硕士

【摘要】 超硬材料具有高硬度、高耐磨性等特点,使用传统的机械方法成型加工比较困难,而特种加工是加工这些超硬材料的有效方法。在难加工材料和精密加工中,超声加工技术具有普通加工无法比拟的工艺效果,将超声加工和电火花相结合进行复合加工,常常能大幅度地提高加工速度、改善加工质量和完成一般加工方法难以完成的加工工作。因此,被广泛地应用于国民经济的各部门,并有广阔的应用前景。本文在理论上分析了超声电火花复合加工的加工机理及超硬合金、聚晶金刚石、导电陶瓷三种超硬材料的性能及用途。针对超硬材料的超声电火花复合加工试验,分析了超声振动对间隙放电状态、放电通道的形成的影响以及超声对放电凹坑、表面显微组织的影响。通过试验方案的设计,运用超声电火花法对这三种超硬材料进行加工,研究脉冲宽度、超声振幅、磨粒大小对加工效率的影响以及加工中电极的损耗情况。并进一步分析了电火花加工对超声加工的影响,并对超声电火花复合加工中的放电情况进行一定的分析。超声复合加工中的电火花放电是一个复杂的过程,电火花加工对超声加工的加工效率和加工精度有一定影响。试验结果表明材料的去除率随着脉冲宽度、超声振幅的增大而增大;加工表面粗糙度随着脉冲宽度、超声振幅的增大而增大,磨料颗粒的大小也影响了加工表面粗糙度。更多还原

【Abstract】 Super-hard material has characteristics of high hardness and high wearability. It is difficult to machine it by the traditional mechanical method. Non-traditional machining is an effective way to process the super-hard material. In the difficult-to-cut material machining and precision machining, the ultrasonic machining technology has the effect that general processing technology can not match. The combination of ultrasonic machining and electrical discharge machining (EDM) can greatly improve the processing speed and quality. This technique can complete the processing work that general processing method can not finish. Therefore, it has been widely used in various national departments and has broad application prospects.In this paper, the mechanism of ultrasonic hybrid EDM in super-hard material processing and the properties of super-hard alloy, polycrystalline diamond (PCD) and conductive ceramic are introduced. The effect of ultrasonic vibration on the gap discharge status, discharge channel and the surface microstructure is studied. A set of experiments are designed to machine the three kinds of super-hard material with ultrasonic hybird EDM. In this way, the impacts of pulse width, ultrasonic amplitude and abrasive size on the processing efficiency are obtained. The attrition of the electrode are also introduced here. The impact of EDM process on ultrasonic machining and the discharge situation are analyzed. The results show that EDM has some impact on the efficiency and accuracy of ultrasonic machining.The discharge of EDM in the experiment is a complex process.The results also show that the material removal rate increases if the pulse width and ultrasonic amplitude increase. Surface roughness becomes larger when the pulse width and ultrasonic amplitude increase. The size of abrasive particles also has a certain impact on the roughness.更多还原