Improve the accuracy, surface smoothing and material adaption in STL file for RP medical models

Abstract

Manufacturing of accurate medical models from Digital Imaging and Communication in Medicine (DICOM) images is one of the useful techniques in case of complex medical surgeries. The DICOM images (voxels based data) were transformed into STereo Lithography (STL) file (triangle based data) format. This is used for manufacturing of medical models with Rapid Prototyping (RP) technologies. However, there are always chances of having some defects like inaccuracy and rough surface finish of the RP model due to erroneous in STL file. The proposed smoothing g algorithm is developed with combination of interpolation and mesh construction methods were used for producing an accurate and smoother STL file. The proposed smoothening algorithm was implanted on dry mandible STL file in the current study. The dry mandible STL file is primarily split into slices of equal thickness along the Z-axis direction. Each slice contour data information was created as a Common Layer Interface (CLI) file. These contour data points are increased further improved contour accuracy by Fast Fourier Transform (FFT) method. As well as, these contour data points are used to generate a surface and STL file simultaneously by the Delaunay triangulation method. By applying this novel combination method, the generated STL file accuracy and smoothness were improved when compared to the initial STL file. Furthermore, this algorithm is applicable for trimming and hole-filling operations in STL files by changing the triangulation angle.