Measurement And Evaluation Of Three Dimensional Surface Roughness

The surface roughness has a decisive influence on the physical properties such as wear resistance,contact stiffness,corrosion resistance,fatigue resistance,sealing and fitting of two workpieces and so on.The physical characteristics of the parts will directly affect the working performance of the assembled equipment,the accuracy of product processing,the operation reliability of equipment and the effective life of equipment.At present,the two-dimensional measurement of surface roughness has been relatively perfect and the evaluation method has also formed a unified international standard.However,the surface information obtained from two-dimensional parameter calculation can not fully reflect the micro morphology of the workpiece surface,and can not judge the surface characteristics of the workpiece comprehensively from the surface morphology.Three dimensional surface roughness information and 3D roughness parameters can reflect the shape and performance of the surface more comprehensively and intuitively,so the study of 3D surface roughness measurement and evaluation is more and more important.In this paper,the method of measuring 3D surface roughness based on white light phase-shifting interferometry is studied theoretically,and the experiments are carried out.Then the roughness of the 3D surface profile measured by the experiment is evaluated.In this paper,it is introduced that the purpose and practical significance of3 D surface roughness measurement and evaluation.And the current development situation in domestic and international is summarized and discussed.It discusses the method of non-contact measurement based on white light phase-shifting interferometry and establishes the three-dimensional evaluation parameter model.The measurement system uses white light as interference light source.Forthe interference fringes collected by CCD,the algorithm combined with the digital filter and the two curve fitting is used to calculate the height of each sampling point,and to restore the original surface profile.The Gauss B spline approximation filter is used to establish the three-dimensional surface evaluation datum,and the 3D profile of the surface roughness is presented.The simulation results show that the error of the measurement system is not more than 3.5%.In this paper,the definition and expression of all kinds of 3D evaluation parameters are given,and the parameters of the roughness profile are calculated.Based on the experimental results,the surface roughness of the grinding sample block and the end milling sample block is analyzed.The results show that the results of the analysis are in accord with the actual surface characteristics.Finally,the problems existing in the measurement system and evaluation methods are summarized and analyzed,and the research work is prospected.