Reconstruction of 3-D CAD Model of Workpiece With Internal Defect Based on Industry CT Image

A 3D CAD model of workpiece with internal defect can effectively evaluate the effect of internal defect on the use performance of the workpiece by digital simulation, and the analysis result can provide technical support for optimizing manufacturing process, but how to obtain the model has always been a difficult problem. A reconstruction approach is proposed for 3D CAD model of workpiece with internal defect based on industrial CT image in this paper. Firstly, the CT image data is achieved by use industry CT scan the workpiece with internal defect, then the internal defect is segmented from the volume data composed of industrial CT images. The STereoLithography (STL) model of the workpiece (excluding defect) and the STL model of the internal defect are obtained via the 3D surface reconstruction of volume data. Then, in order to obtain the correct position of internal defect in the nominal CAD model of the workpiece, the STL model of the workpiece (excluding defect) is registered with the nominal CAD model. Finally, the CAD model of internal defect is reconstructed, and then the 3D CAD model of workpiece with internal defect is achieved by Boolean operation with the entity model of internal defect and the nominal CAD model of workpiece. The reconstructed CAD model of workpiece with internal defect is imported into the finite element simulation software, and the simulation analysis can be carried out according to the needs, which proves the effectiveness of the method in this paper. The proposed method make full uses the nominal CAD model of workpiece, and only need to reconstruct the CAD model of internal defect, which is simple and efficient.