【作者】 于春明；

【导师】 杨兆军；

【作者基本信息】 吉林大学 ， 机械制造及自动化， 2007， 硕士

【摘要】 碳化硼工程陶瓷因其优良的物理化学性能而得到越来越多的关注,但是超高的硬度给传统的切削加工带了困难,从而严重限制了它的广泛应用。近年来,电火花加工工程陶瓷成为国内外学者研究的热点。而本文主要对电火花线切割加工碳化硼工程陶瓷进行了两个方面的研究,一是加工参数对加工表面质量的影响规律研究,二是以最佳表面质量为目标的加工参数的组合优化研究。在加工参数对表面质量的影响研究中,采用了单因素的试验方法,分别分析脉冲宽度、峰值电流和脉间/脉宽比对表面质量的影响及影响规律。并与金属加工的情况对比,通过扫描电镜分析微观形貌来解释两者差异存在的原因。然后结合单因素试验的结论,选定试验因素的水平,通过正交实验并用极差分析法处理试验数据得出最优参数组合。通过单因素的试验研究,发现各个加工参数对表面加工质量有不同程度的影响,规律也各不相同。最优的参数组合通过正交试验获得,并且在此参数下能加工出具有很好表面质量的直壁表面。更多还原

【Abstract】 B4C engineering ceramics is focused as a very important material for its excellent performance of physics and chemistry. Its rigidity is inferior to diamond which challenges the traditional machining method and restricts its application badly. For the electrical resistivity of B4C is 0.3-0.8?·cm in normal temperature and the EDM can machine the material whose electrical resistivity is less than 100?·cm, the EDM becomes the key method for the wide application of B4C .Wire electrical discharge machining is an unconventional method which machines the material with a soft wire. The feasibility of machining with EDM is only related to the electrical resistivity no matter how hard it is which is different from traditional machining method. The difference from the traditional machining method is made use of to machine the B4C engineering ceramics which is not accomplished by traditional machining method. This paper based on the research results both here and abroad, mainly completed two part research items. One research is about the effect rule of ti, toff/ti and ie to the finished surface quality, the other one is to optimize the combination of the three parameters in order to maintain the best combination.The single factor experimentation of the three parameters discussed the effect rule of ti, toff/ti and ie to the B4C engineering ceramics finished surface quality and analyzed the micro view of the finished surface through ESEM getting a straight understand. The differences are discussed trough the contrast between the experimentations of both metal and B4C engineering ceramics. The disfigurements—crack and“knurl”of the finished surface are found in the contrast experiments of the peak current which are explained through making the removal mechanisms clear. In the contrast experiments of the toff/ti, the rules of effect for both metal and B4C are unified by the curve of“the three ranges curve of the finish surface quality and toff/ti”which proved that the effect rule of toff/ti for finish surface can be explained by only one theory curve no matter what the material is.The best combination of the three process parameters is optimized by the orthogonal test which is got by the design of the experiment technique. All the data of the results is analyzed by analysis of range. The primary and secondary effect factors and the optimized combination of the three process parameters are got through different data processing of the experiments data which are obtained through different measurement. And the results are validated later to make the final decision.Some researches are made about the effect rule of the process parameters for the finish surface, the differences between metal and B4C are found through contrast experiments and the reason is explained in theory and practice. The optimized combination and the satisfying surface quality are gained through the orthogonal test, with the roughness by straightforward measuring reaching 0.369μm and by perpendicularity measuring reaching 0.414μm. But the cognition for the removal mechanisms is not clear yet.更多还原