Research And Implement Of The Method Of Generating NC Codes Based On Industrial Computed Tomography Slicing Image

A method of generating NC codes, based on the datum measured by industrial computed tomography(abbr. CT) is proposed in this paper. The method mainly faces reverse engineering which aims at profile modeling. This paper's principal study contents are as follows:First of all, the ICT slice image preprocess, of which the goal is extracted the datum of contour boundary, is studied. The contour of the slice image is extracted by the process of image denoising, image segmentation and image edge detection. Then the contour datum of the sample, which are datum are continuous and close, are acquired by the contour tracing method of eight pixel neighborhoods.Secondly, two tactics of contour fitting is studied: the method of line-arc fitting and the method of B-spline curve fitting. Based on combination of curvature with curvature difference, rough characteristic points are detected. And precision characteristic points are extracted by the algorithm of decomposing and incorporating. Afterward, the characteristic points are taken as subsection point of the contour line and the type of every segmented line is identified. Then according to identified line type, we can be more rational to select the contour fitting means—line-arc fitting or B-spline curve fitting. In this part, the research on B-spline curve fitting is laid a strong emphasis on, in which it is proposed that data points selection is based on characteristic points extraction and segment line type identification.Thirdly, it is researched that NC codes are directly generating on the basis of contour datum after fitting. In the beginning, the technology of numerical control machining in existence based on the measured datum is analyzed. And an approach of directly generating NC codes is presented in this paper: by introducing machining technology in any plane region, the roughing tool-path is generated; afterwards, an approach of sectional plane based on equidistance slice contour is employed to generating finishing tool-path; and then NC codes are transformed according of ISO standard.Finally, a soft system, on the basis of the method presented in the paper, is designed and developed.The method proposed in the paper needn't rebuilt a CAD model of a sample, which can enhance the efficiency and save resourses. The ICT slicing images of two samples are taken as examples. The codes, that may be used for manufacturing , are acquiredthrough image preprocess, contour fitting and NC codes generation. And the codes transformed in fomat are inputted to the manufacturing emulation software—MasterCam to emulate manufacturing. The result of emulating verifies the feasibility of an approach proposed in this paper.