Behavioural Study On Contact Characteristics Of Solid-liquid Interface And Filling Flow In Constrained Molding Room

In the Continuous Liquid Interface Production process,the peeling force between the cured layer and the constrained substrate is significantly reduced by using the effect of oxygen polymerization resistance,which significantly improves the printing speed.However,in order to meet the printing speed requirements of 3D printing from rapid prototyping to large-scale direct manufacturing of functional parts,the solid-liquid interface adhesion is still the main problem which affects the process reliability under the high-speed printing condition.This paper studies the influencing factors and mechanism of the interface adhesion in the Continuous Liquid Interface Production process,and provides the theoretical basis for the design and process optimization of the forming molding room substrate.major work and conclusions include:The formation mechanism of adhesion force is theoretically deduced in detail,and the negative pressure is the main reason for the formation of suction force;the finite element calculation model is established considering the solid fluid interaction effect between the substrate and resin interface.The adhesion force under different parameters(platform rising velocity,acceleration,print part section area,dead zone thickness,substrate surface with or without slip,release film thickness)were calculated.The distribution characteristics of the negative pressure and the influence of different parameters on the adhesion force are compared with the theoretical results and the results of not considering the solid fluid interaction.The results show that the adhesion force increases with the increase of printing velocity,acceleration and printing section area;it decreases with the increase of dead zone thickness and release film thickness.the Adhesion force can be reduced significantly by interface slip.Considering the constraints of specific printing tasks and process conditions,the most effective way of reducing the adhesion force is to build slip interface.It is necessary to construct the surface micro-texture for realizing the interface slip.The interface contact state between the printing material and the micro-texture affects the slip characteristics.Therefore,COMSOL software is used to simulate the resin flow behavior on the surface of micro-nano structure,and the influence of different texture parameters on the slip velocity and the degree of devitrification is analyzed.The results show that the slip velocity and the slip length increase with the increase of the diameter of micro construct;it decreases with the increase of the spacing and the depth of micro construct.There is a more effective drag reduction effect when the diameter of the micro construct,the distance between the micro construct and the depth of the micro construct are 200nm,400nm and 3 50nm,respectively.the results of simulation can provide a reference for the parameters of experimental surface texture preparation.The adhesion force with different parameters(dead zone thickness,cross-sectional areas and velocities)are measured online through experiments by constructing the cured layer peeling process in CLIP.the motion precision and the repositioning precision of the Z-axis stage are analyzed.The measurement results show that the precision is good for experimental need.The realization scheme of the thickness of inhibition zone is designed and implemented.The experimental results are consistent with the simulation results considering substrate deformation.