Calculating volume of defects in casting objects is important for high quality manufacturing. It can be estimated by using X-ray CT scanner that is a non-destructive measurement device. However, conventional methods cannot detect tiny defects based on simple thresholding method. This is because not only their CT values do not fall down to the value of background but also they appear like one set in CT images. As a result, we do not take into account such tiny defects and their calculation accuracy is comparatively low. In this paper, we propose a more accurate method to calculate casting defects' volume. We define two types of defect by their size and apply different calculation models to each defect. We propose a method to separate each defect from the set of defect based on assumption that a tiny defect is approximation of sphere. Our contribution is to detect tiny defects which are not detected or calculated correctly in conventional method and to calculate their volume. This paper also demonstrates more accurate estimation of defects' volume using measured CT data.
Hiroyuki Hishida, T. Michikawa, Hiromasa Suzuki
Journal of The Japan Society for Precision Engineering