Research On Key Technologies Of Ultraviolet Curing Mask-image Projection Stereolithography

In recent years,the mask-image projection stereolithography in the field of photo-curing has become a research hotspot.This article focuses on ultraviolet exposure,choosing the uniform exposure scheme in the ozone mask method,the development of matching resin materials,and the key technologies such as ceramic-enhanced liquid crystal(LC)masking process.The main contents of the research are as follows:(1)Around the ozone mask surface exposure method,the photochemical reaction process in the mask enclosure was analyzed.Basing on the molecular structure and energy level of oxygen and ozone,the energy level of each configuration in ozone photolysis under dual ultraviolet action was revealed.The 254nm radiation of the plasma discharge electrodeless lamps were used as the exposure and curing energy,and the square rod homogenization system was used to simulate the light field distribution of a single electrodeless light source at a distance of 5mm,6mm and 7mm from the receiving surface;then,a fly-eye lens were used to make more The electrodeless lamps are uniformly distributed.When the total power was 700W,the light field distribution of the multiple electrodeless lamps at the distance of 20mm,25mm and 30mm from the receiving surface of the compound eye were simulated.According to analyze the intensity and lost light intensity,the better uniform exposure scheme was obtained.(2)A photosensitive resin system material was developed to match 254nm curing,and its curing performance was initially verified.According to the selection principle of photosensitive resin components,the combination of EA-A,EA-F and PUA were selected as the prepolymer,the combination of TPGDA and ETPTA were selected as the diluent,and initiators absorbed in wavelength of 254nm were selected as the photoinitiator.By changing the ratio and content of each component,viscosity,curing time and hardness after curing were applied as indicators.The gradient experiment of the controlled variable method was employed to compare the indicators,and the best matching scheme of each component and content was obtained.(3)Adopting the method of adding alumina to enhance the photosensitive resin material,the research was carried out on the LC mask process.The single factor analysis method was applied to study the effects of exposure time,bottom layer exposure time,and light-off time on the accuracy and mechanical properties of the parts.Basing on the method of orthogonal experiment and signal-to-noise ratio analysis,the Z-direction dimensional accuracy and hardness were used as evaluation indicators.The process was optimized through range analysis.According to the optimized process parameters,this had been validated in the production of commercialized 3D facial artistic models.