Evaluation of Surface Roughness of Machined Surfaces Using Vision System

Abstract

Surface roughness Measurement of machined components helps in predicting the success or newlinefailure of component when it is put into service. Surface roughness measurement is also used to newlinejudge stability of manufacturing process. Surface roughness evaluation is also used for newlinemonitoring the condition of cutting tool or machine tool. Any change in process parameter or newlinecondition of the cutting tool results in changes in surface geometry and texture. newlineSurface texture is comprised of three components- roughness (Short Wavelength), waviness newline(medium wavelength) and form Error (large wavelength). Evaluation of texture of machined newlinesurfaces can be done either by contact or by non-contact methods. Roughness measurement by newlinestylus instrument is a most popular of the tool methods. Though stylus based instruments provide newlineaccurate readings they required direct physical contact with the work surface which limits its newlinemeasuring speed. It is a line sampling inspection method and hence may not represent the real newlinecharacteristics of the surface. newlineMost of the non-contact surface roughness measurement methods are based on optical or electrooptical newlineprinciples. These methods have high measuring speeds. However they do not provide newlineinformation necessary for full characterization of the surface. Also, they can not be employed in newlinesituations requiring automation. newlineTexture measurement by contact methods using stylus are very accurate but are restricted to a newlineline sampling based measurement scenario. To overcome these drawbacks of contact methods newlineresulted in the development of non contact surface roughness measurement techniques; many newlineresearchers have started using vision system for surface texture assessment. Many of these newlinetechniques were focused on the surface roughness evaluation of machined surfaces. However newlinethese methods do not provide the complete characterization of the surface. newlineIn this context, the proposed approach evaluation of surface roughness of machined newlinesurfaces using vision system assumes special significance.