Study Of Hierarchical Algorithm And Path Generation Strategy In 3D Printing Technology Of Denture Model

With the popularity of 3D printing technology, in more and more fields, 3D printing technology is regarded as a popular technology. In the medical field, because of its advantages such as simple operation, accurate positioning, the development of 3D printing technology is rapid, what’s more, in oral medicine, 3D printing technology can also be applied. Apply 3D printing technology in denture can make the printed tooth similar with the natural tooth in both structure and function, achieving a better satisfactory effect of repair, what’s more, now denture 3D printing has become the first choice for more and more patients.The main research contents of this paper include: STL model of denture is read and modeling, the analysis of which is carried on, on the basis of which design adaptive slicing algorithm, so reduce the volume deviation between the printed model and the theoretical model, and then extract the outline of different layers, match them with non rational B-spline curve(also known as NURBS), finally, combine the offset curve path and zigzag tool path, design the speed control strategy for both of them and choose the optimal distance between the tool path.At the first part of this paper, the STL model of denture is read and visualized, then on the foundation of former develop the hierarchical algorithm, design a kind of adaptive slicing algorithm based on the uniform hierarchical algorithm suitable for denture, which mainly solve the loss and deviation of feature of,the model, both the accuracy and efficiency of the layered are considered. Then the contour of the current section is extracted by tracking the points in the slice, finally, use the nearest distance analysis to correct the problem of distortion or open loop.The second step is tool path generation, mainly carried out by the following steps: introduce the non uniform rational B spline curve to represent the contour of each layer, solve the control points by algorithm, then set different offsets according to the control points to generate the offset curve tool path, and use zigzag paths to fill in the part that the offset tool path can not arrive.The last step is on the foundation of former, develop a hybrid adaptive tool path generation algorithm aimed at optimize the surface quality and production efficiency of the denture in 3D printing, design the speed control strategy for the overall tool path, at the end of this part, the multi-objective optimization method is applied to optimize the spacing of the zigzag tool path, so that the area error of the contour, the material overlap rate and the build time can all be optimized.Complete the reading, layering and tool path planning of the model through the above three steps. The simulation results show that the slice contours can be accurately extract, and the tool path space achieved by the multi-objective optimization method is optimal and the speed control strategy can make the construct time largely shorten under the premise of ensuring the accuracy. The tool path generation strategies, speed optimization strategy and tool path interval optimization strategy is feasible in this paper.