Research On Forming Mechanism And Accuracy Of Double Ultraviolet Mask Projection Stereolithography Technology

There are many technical schemes for mask projection stereolithography.The requirement of single exposure area and accuracy are an impotant index of the process equipment.The existing equipment is limited by mask devices,and it is difficult to cure in large area.The shrinkage deformation of materials is also a prominent problem in resin preparation.In this paper,a new method of double ultraviolet ozone mask proposed by the team was studied,and its forming accuracy was studied.Rapid casting was validated by mask projection stereolithography prototype.Firstly,the influence of light energy on the light curing process,the distribution of light energy and the shape of micro-curing accumulator in the existing light curing process were analyzed,and the light paths of different processes were compared.The mechanism of the new double ultraviolet ozone mask,the continuous liquid interface production mechanism under the action of oxygen inhibition,and the gas-liquid-solid three-phase interaction mode of oxygen between the oxygen permeable film and the resin were deeply studied,which provided the basic theoretical resear-ch for the large-scale surface forming.Secondly,the deflection of oxygen permeable membrane caused by gravity fluctuation of resin was studied.The deformation of oxygen permeable membrane under prestressing aind non-prestressing,the deformation of different shapes of oxygen permeable membrane under the same prestressing,and the way of prestressing were analyzed by workbench.The prestressing forced that met the requirement of deformation accuracy was obtained,and the actual tightening of oxygen permeable membrane was verified.Finally,the shrinkage of resin in mask projection stereolithography was studied.The influence of different single factor process parameters on the shrinkage of resin was studied by factor analysis method.The response surface analysis method was used to study the multi-factor level,and the influence of the coupling of process parameters on the shrinkage was analyzed.The optimized process parameters were obtained by quadratic regression equation fitting,and the shrinkage under the optimal process parameters were used as compensation factor.The correctness of the optimized process parameters were verified on the complex diffuser parts.On this basis,the improved diffuser resin prototype was applied to the case study of rapid casting,and the precision aluminum alloy castings meeting the requirements were obtained.