A Wavelet Approach to Estimate The Quality of Ground Parts

Abstract

The manufacturing process of metal parts is subjected to machining instabilities that can degrade the surface finishquality and the reliability of products. Some instabilities are of transient nature and traditional inspection systems areunable to adequately estimate the grade of affectation in the finished parts. Time-frequency analyses are techniquesthat overcome these limitations and have recently been incorporated in special industry inspection equipment toimprove the quality of the manufactured parts. Grinding is a process used to get high precision and very smoothsurface in flat or cylindrical parts because of the target applications such as the automotive industry where the higheststandards can be found. This paper reports a technique to estimate the quality of ground parts based on timefrequencytransforms that are used to enhance the defects. This makes it easier to implement the technique forsurface characterization in online pass/no-pass inspection machines. The fundamentals of the methodology arerevised and the technique is applied to the identification of vibration marks in cylindrical ground rods. Results showthat this approach identifies adequately imperfections of transient nature and it is able to estimate the extension andamplitude of the defects on the surface of the manufactured parts.