Study On The Layer Direction And Tool Path Optimization In 3D Printing Denture Technology

With the advancement of science and technology,3D printing technology has developed rapidly and has been applied in various fields.In oral medicine,3D printing denture technology compared with traditional manufacturing technology,can largely improve the efficiency of printing and printing precision,the result to be more perfect,can produce implants that are similar to the structure of the teeth,i.e.non-physical.3D printed denture has hierarchical structure,personalized,easy to integrate with human tissues,shorten the recovery period,reduce the pain of patients and give consideration to beauty.3D printing technology makes it possible to digitize the future of oral cavity repair.The main contents of this research are as follows: first,select the best direction of stratification and analyze it by reading the STL model.Based on the linear regression theory,the volume error is calculated at different slice thickness,so that the direction of the smallest volume error is the optimal direction of stratification;Then,the path optimization is designed.The irrational B spline curve(NURBS)is used to fit the extracted denture contour.In addition,the contour is filled by the contour offset algorithm,and the inner contour is filled with Z scan,and optimize the filling path;Finally,the integral separation fuzzy PID control method based on the traditional PID algorithm and fuzzy control algorithm is used to control the temperature of the nozzle.In this article the first step is to read the STL of the denture,analyze the staircase effect produced in the delamination,and establish a volumetric error model,The minimum volumetric error is calculated according to the linear regression principle,that is,the shadow sum the normal vector of the triangular surface in the layering direction,the minimum volume error is calculated by using C language,and then select the best layering direction,so that the accuracy of the printed denture model is the highest.The second step is to extract the outline of each layer,and then using the non rational B spline curve to fit,then optimize the tool path,filling the denture model with a composite filling method: contour offset mode and Z type filling method,the outer contour is filled with internal offset,and the inner contour is filled with the offset,the inner filling is Z type filling,the transverse filling is adopted in the odd layer,and the longitudinal filling is adopted in even layers,to make print denture model more solid,smooth surface and the highest accuracy.The third step in the 3D printing packing process,to control the nozzle temperature,using reasonable strategies to ensure the continuity and adhesion properties of nozzle silking,the integral separation PID control method based on Fuzzy here,ensure the nozzle temperature steady performance and strong robustness,and guarantee the printing process continues and the accuracy of denture.To sum up,in this paper,the high precision requirements of 3D printing denture,the study is carried out from the discrete process to the accumulation process.The simulation results show that the volumetric error is inevitable,but the volume error can be minimized by selecting the optimal layering direction,and improve the accuracy of the printing denture.The nozzle filled according to the optimized tool path.control the nozzle temperature system,make the printing process more stable,improve the quality of printing model.