Manufacturing Technology Today

Kedar H. Inamdar ¹, S. G. Joshi ¹

Affiliations
1 Department of Mechanical Engineering, Walchand College of Engineering, Sangli-416415, IN

Abstract

The three-dimensional roughness measurement is most proper way for the representation of topographical surface details; therefore in this paper, some vision-based three-dimensional optical statistical spatial parameters are computed by considering values, corresponding to gray scale intensity values, Red-Green-Blue (RGB) and Hue-Saturation-Intensity (HSI) colour models, at each pixel of the digital image. The statistical parameters such as average value, standard deviation, skewness, kurtosis etc. for the magnitude, slope and curvature corresponding to the intensity values over the surface have been computed.

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Kedar H. Inamdar ¹, S. G. Joshi ¹

Affiliations
1 Department of Mechanical Engineering, Walchand College of Engineering, Sangli-416415, IN

Abstract

In part-1 of the paper, a new convenient and comparatively less expensive technique for the evaluation of surface roughness has been presented. Various three-dimensional statistical parameters have been proposed for the comparison of surface roughness of the test surface with standard surface. In this part of the paper, a variety of surface specimens with different roughness values, various types of lay-patterns, with and without any error (defect) and similar as-well-as different materials, have been taken for the comparison/analysis of the surface roughness. The observations and the results of the comparison/analysis of the surface roughness have been presented for the various cases using the method as proposed in part-1. In addition, the comparison between standard and test surfaces is also carried out and illustrated by graphical representation.

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Kedar H. Inamdar ¹, S. G. Joshi ¹

Affiliations
1 Department of Mechanical Engineering, Walchand College of Engineering, Sangli-416415, IN

Abstract

In almost all manufacturing processes, it is always observed that some irregularities are always present on the surface and a surface finish plays an important role for the quality of the product. Hence, an evaluation of the surface roughness is very essential. A number of methods are widely used in practice. However, all these methods have some limitations of measurement. In this paper, a comparison-based method for measurement of roughness of flat surfaces using a low cost 'Computer Vision System' consisting of a flat bed optical desktop scanner connected to a personal computer (PC) is proposed and developed. The machined surface under test is viewed by the scanner and its two-dimensional image is obtained. The image is then digitised and stored in the computer memory, which is further processed using digital processing techniques and then analysed.
It is observed that the values of the R, G, B colour components and Gray scale intensity at each point on the digital image depends upon the configuration of the surface at the corresponding point of the test surface. Thus, the parameters such as mean, standard deviation etc. for the intensity levels measured on the digital image is an indication of the surface configuration i.e. surface roughness. The values of the parameters thus obtained for a surface under test are then compared with the corresponding values of the standard (reference or master) surface obtained by a carefully monitored machining process. To compare the roughness of the test surface with that of the standard surface, additional statistical parameters such as Coefficient of Variance, Kari Pearson's Coefficient of Correlation, Equality Index based on Fuzzy Sets etc. are also computed. This method of comparison between the parameters evaluated for digital images of test surface and standard surface obtained from computer vision system is less expensive, yet more effective option for the evaluation of roughness of very smooth machined surfaces (even in the range of nano-meters) for finished products used in general, as well as areas of micro-electronics, bio-medical and surgical equipments etc.

Full Text

     

Kedar H. Inamdar ¹, S. G. Joshi ¹

Affiliations
1 Department of Mechanical Engineering, Walchand College of Engineering, Sangli-416415, IN

Abstract

In part-1 of the paper, a new convenient and comparatively less expensive technique for the evaluation of surface roughness has been presented. For the comparison of surface roughness of the test surface with standard surface, various parameters have been proposed in the part-1 of the paper. In this part of the paper, a variety of surfaces with different kinds of errors and lay-forms for the same material, have been taken for the comparative analysis of their surface roughness. The results of comparison of the surface roughness using the method as proposed in part-1 for the various cases have been presented. In addition, the comparison between standard and test surfaces is also illustrated graphically by histogram graph and 3D representation.

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