Research On Surface Roughness Evaluation Of Micro-EDM

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.