Analysis And Hydrophobicity Of Micro-nano Additive Manufacturing Process Based On SLA

Hydrophobic surfaces are widely used in biomedicine,clean energy,military and national defense fields because of their special wettability such as self-cleaning and antiadhesion.However,at present,hydrophobic surface is still faced with the disadvantages of complicated process,time-consuming,high cost,environmental protection and so on.Therefore,this paper aims at producing hydrophobic surfaces by micro-nano additive technology with simple,efficient and low cost,and studies the influence mechanism of printing process parameters and post curing time on printing quality,so as to optimize the molding quality.Meanwhile,the hydrophobic surface was designed and manufactured based on hydrophobic theory,and the contact Angle measurement experiment was carried out to study the influence of structural parameters on hydrophobicity.The main research contents of this paper are as follows:Firstly,the system composition and additive forming mechanism of the equipment are described.Environmental scanning electron microscope(ESEM)was used to analyze the components by EDS.The process of additive forming was divided into three stages:pre-preparation,printing and post-treatment.The factors affecting the quality of additive forming were analyzed according to the uneven quality and deformation of microstructure forming.The results show that C,O and N are 71.3%,24.11% and 4.59%respectively.The optimal post-curing time is 5-10 min,when Ra is about 29 nm and Shore hardness is about 87.9 HD.Then,the optimization of micro-nano additive molding process parameters is carried out.Through the design of orthogonal test,print the model and characterize the micro morphology.Using range analysis and multi-index optimization methods were used to analyze the micro-cylinder and micro-cone with the bottom diameter of 50 ?m,and finally to optimize the process parameters of the micro-structure forming of the cylinder and the micro-cone.The results show that the order of influence of process parameters on molding quality is: exposure time,print layer thickness and umber of vibrations.After optimizing the process parameters,the cylindrical structure with the diameter of 30 ?m,height of 400 ?m,and the cone with the cone Angle of 5° and a top diameter of 2.876 ?m can be formed.According to the characteristics of additive forming,cylindrical,square,conical and pyramid structures with variable parameters were designed and printed based on hydrophobic principle.The best geometric structure is cylindrical and conical through comparative analysis.Column height to diameter ratio should be less than 8,cone Angle should be less than 12°.In order to study the influence of the changes of the microstructure geometry,array spacing and diameter parameters on the hydrophobic effect,an array structure with varying parameters was designed and printed based on the hydrophobic theory of Young,Wenzel and Cassie-Baxter equation.Finally,the hydrophobicity analysis of the additive forming parts was carried out.In order to reduce the measurement error,the measurement method,droplet volume,test environment and so on were analyzed.After analysis,the measurement method with high volume should be preferred,and the droplet volume should be between 2.5-7 ?l.The contact Angle test was carried out after the parts were soaked in fluorosilane solution to reduce the surface energy.The experimental results show that the optimal static contact angles are 139.6°,142.9° and 143.6°,respectively,for the arrays with 100,50 and 30 ?m cylindrical diameters.The optimal static contact Angle and rolling Angle of conical array are 157.1° and 3.5° respectively.The static contact Angle increases first and then decreases with the increase of array spacing.The decrease of cylinder diameter is beneficial to improve the hydrophobic effect,and the hydrophobic effect of cone is better than that of cylinder structure.The experiment effectively verified the feasibility of slabased micro-nano additive technology for preparing micro-nano structures on hydrophobic and superhydrophobic surfaces.