【作者】 陈志杰；

【导师】 沈继红；

【作者基本信息】 哈尔滨工程大学 ， 系统工程， 2011， 博士

【摘要】 随着科学技术的发展和世界范围产品的小型化、精密化,微细加工技术正备受世界各国研究学者的关注。微细电火花加工技术以其较高的加工效率、较好的加工质量、可以加工微细、高硬度、复杂形状的三维零件等优势,在微细加工领域占有越来越重要的地位。零件的表面形貌提供了很多重要的表面信息,对零件的摩擦、润滑特性有重要影响。然而,微细电火花加工表面形貌的评定问题,学者们一直采用切削加工表面形貌的评定参数和评定方法,这制约了微细电火花加工技术的进一步发展。基于此,本文针对微细电火花加工技术的特点及其加工工件表面形貌的特点,进行了微细电火花加工表面粗糙度评定的研究。首先,分析了微细电火花加工表面粗糙度对零件使用性能的影响,针对影响其表面粗糙度使用性能的无数的微小凹坑和凸起的高低、陡峭程度和间距状态等特征,提出了描述微细电火花加工表面粗糙度评定参数,并给出相应参数的数值计算方法。接着,针对微细电火花加工表面形貌的特点和小波分析具有的良好时域、频域局部化性质,能够观察分析信号的任意细节的优点,确定微细电火花加工表面粗糙度评定基准使用小波评定基准,并对常用的小波函数的优缺点及特性进行了分析比较,选择微细电火花加工表面粗糙度评定小波评定基准的小波函数为Daubechies小波。然后,研究了基于小波分析方法的微细电火花加工二维和三维表面粗糙度提取的可行性,并建立了小波分析方法提取其二维和三维表面粗糙度数学模型,同时使用Daubechies 4小波和Daubechies8小波对微细电火花加工表面粗糙度的小波评定基准算法进行了仿真实验,仿真结果表明：对于不同组的采样数据,使用不同的小波函数都可以提取微细电火花加工表面粗糙度,而且对于同一组采样数据,使用相同的小波函数,分组数目不同不影响小波分解次数的确定,使用不同的小波函数,也不影响小波分解次数的确定。最后,对本文提出的微细电火花加工表面粗糙度评定参数,使用基于小波分析方法的微细电火花加工三维表面粗糙度提取算法,对四个工件表面形貌数据进行了仿真实验,得到了它们的表面粗糙度参数值,而且这些参数值能够一致地反映出某个工件整体的使用性能好坏；用高斯滤波评定基准对该四组数据进行了表面粗糙度的提取和表面粗糙度参数评定的对比实验,结果表明：小波方法得到的表面粗糙度参数值与高斯滤波得到的表面粗糙度参数值,在反映四个工件中哪个工件整体性能好的结果是一致的；同时,对微细电火花加工工件表面形貌在各个区域是否均匀,进行了表面粗糙度一致性问题的统计分析。本文的研究是表面形貌表征问题研究的一个完善与发展,也是微细电火花加工表面形貌评定研究的一个起点。同时,本文的工作也对提高微细电火花加工技术水平具有重要的理论意义。更多还原

【Abstract】 With the development of science and technology, products are gradually miniaturization and precision all over the world, therefore, micro-fabrication technology is being concerned by the researchers around the world. However, micro-EDM plays more and more important position in the field for its many advantages, for instance, it has high machining efficiency, better processing quality, and can machine complex three-dimensional micro-parts by using high hardness materials and so on.Research shows that the surface morphology of workpieces provides a lot of useful information, which has serious influence on the friction and lubrication characteristics of the surface. However, for the micro-EDM’s surface topography evaluation problem, researchers have been using surface roughness parameters and evaluation method of mechanical process, which restrict the micro-EDM’s technology further development. On this account, the surface roughness assessment of micro-EDM has been deeply studied in this paper according to its technology characteristics and the workpieces surface morphology characteristics. The main researches and creative points are as follows:Firstly, the influence that the surface roughness of micro-EDM’s parts impact on their using performance is analyzed and based on the surface morphology characteristics which are the countless tiny pits and uplift with different height degree, steep degree and spacing state, some evaluation parameters and their numerical calculation are given.Secondly, because of the advantages of wavelet analysis which has good time-frequency localization property and can analysis the signal’s any detail, the wavelet reference assessment is chosen to pick up micro-EDM’s surface roughness, in which, by comparing the advantages and characteristics of commonly used wavelet function, Daubechies wavelet is selected as the wavelet function of wavelet reference assessment.Thirdly, it is certified that using wavelet analysis for Micro-EDM’s 2D and 3D surface roughness is the feasibility study, and then the wavelet models for picking up 2D and 3D surface roughness of Micro-EDM are presented, in which, the time of wavelet decomposition of the wavelet models for 3D surface roughness is determined by Pearson Chi-square goodness of fit test. Meanwhile, the results of simulation and experiments show that the proposed methods can separate Micro-EDM’s surface roughness well.Finally, according to the proposed evaluation parameters and the surface roughness extraction algorithm, the simulation and experiments and the comparison simulation experiments that Gaussian reference picking up surface roughness are carried out, meanwhile, the results show that the proposed methods can consistently reflect the workpieces’ performance stand or fall. In addition, a homogeneous analysis has been done with statistical method between the whole surface roughness and each part.Therefore, this research is. a perfect and development for surface morphology characterization, also is a beginning for micro-EDM’s surface morphology research, furthermore, it has important theoretical significance for improving micro-EDM’s technical level.更多还原