Design And Optimization Of 3D Printed Objects Lightweight Using Triply Periodic Minimal Surface

Following the trend of energy conservation,low carbon and environment protection,the lightweight design of models has become an important research topic in the field of modern manufacturing.Combined with 3D printing technology,the lightweight design of models can achieve the reduction of product production costs and the application of structural functions by optimizing the internal structure of the model.However,how to achieve the balance between the lightweight design of the 3D printing model and the high specific strength of the structure is a very challenging topic.The triply periodic minimal surface is a smooth and fully connected periodic porous structure expressed by mathematical equations,which has superior geometric and mechanical properties,and it’s widely used in simulation modeling,medical scaffold design,architecture design and other fields.This paper mainly studies the use of this porous structure to carry out lightweight modeling and optimization of 3D printing models.According to the actual force of the target model,combined with the mathematical expression and parameter control of the three-period minimal surface,lightweight modeling and optimization based on the three-period minimal surface are realized.The main research contents and methods in this paper are:(1)Modeling of porous core based on triply periodic minimal surface.Under the condition that the mathematical expression of triply periodic minimal surface is known,combined with implicit surface polygonization algorithm and Boolean algorithm,a three-period minimal surface kernel with regular pores is generated for any input model.In addition,the influence of the parameters and generation algorithm of the triply periodic minimal surface on the shape and volume fraction of the triply periodic minimal surface is discussed,which lays the foundation for the subsequent optimization.(2)Design of porous structure with variable thickness.Using the stress analysis result of the model,the volume fraction of the model is used as the bridge to construct the mapping relationship between the local stress of model and the surface offsetting value,and the entity is generated through the surface mesh offsetting algorithm to realize the variable thickness porous structure design driven by the stress distribution.(3)Functional gradient design based on spatial division.According to the initial stress field of the model,the model is spatially divided,and the method of splicing between surfaces based on the sigmoid function is adopted to realize the smooth transition between the substructures.Combined with the spatial division of the model,the pore size of the model is designed of gradient distribution,achieving an effective combination between the pore size and mechanical properties.In order to verify the proposed design method,finite element analysis was performed on the designed variable thickness porous structure and functionally graded porous structure,and the physical model was printed for experimental verification.The results show that the two methods of variable thickness design and functional gradient design based on three-period minimal surfaces can effectively complete the lightweight design and optimization of any target model.The generated lightweight model has advantages in mechanical properties,topological continuity and connectivity.There are great advantages in this regard distribution and mechanical properties of the spatial division structure.