Study On Improving The Performance Of 3D Printing Sand Mold

3D printing sand molds can avoid dust,and the production environment is good;digital transmission is adopted,which saves information exchange time;the process of making models is omitted,and speed and flexibility are improved;the dimensional accuracy of sand molds is improved,and the casting processing is effectively reduced Margin;to ensure the flexibility of product design and other advantages.Compared with the traditional casting process,3D printed sand molds have problems such as insufficient compactness,lower strength,small sand size,poor air permeability and collapsibility of the sand mold,and large gas evolution.Aiming at the problem of low compaction of 3D printing sand molds,it is proposed to add a new process method in the 3D process-rolling compaction process.In this paper,the basic principle of rolling compaction is explained,and its application in 3D printing is simulated.It is found that after rolling compaction,the changes of various factors in the rolling process have an effect on the strength,air permeability and sand mold strength.The effect of compaction rate,and summarized the law: the smaller the thickness of the rolling layer,the greater the rolling reduction,the higher the strength of the sand mold;the lower the rolling speed,the higher the strength of the sand mold;the size of the rolling roll diameter There is basically no effect on the performance of the rolled sand mold.And the feasibility of rolling compaction in 3D printing was preliminarily verified by SLS printing.Aiming at the problems of large gas generation,low air permeability and poor yield of 3D printed sand molds,a 3D printing method of spatial meshed sand molds is proposed.This article describes the 3D printing method of the spatial grid sand mold,and analyzes the influence of the spatial grid change on the sand mold strength,air permeability and the amount of binder used.The research results show that the 3D printing method of spatial meshed sand mold can greatly reduce the amount of binder added and improve air permeability.Utilizing the characteristics of the spatial grid sand mold can effectively improve the air permeability of the sand mold and reduce the amount of gas generated.The strength and air permeability of the sphere space grid sand type are significantly better than the cube space grid sand type;as the grid size increases and the grid cavity connection skeleton size decreases,the sand type strength decreases and the air permeability increases;with the grid There is no obvious change in the strength of the arrangement mode.The densest packing of hexagons and the face-centered cubic packing have better air permeability,and the amount of binder is the least;the strength and air permeability of the gradient mesh sand type are compared with the cube mesh There is no obvious change,and the amount of binder used is small;the topological skeleton has better air permeability due to the good penetration of the skeleton.Through rolling compaction and spatial grid printing methods,the performance of 3D printing sand molds can be effectively improved,and more feasible methods are provided for the popularization and application of 3D printing sand molds.