Transport phenomena of photo-radicals across dual-wavelength patterning boundaries for super-resolution additive manufacturing

Semi-analytical model that considers reaction–diffusion of photo-radicals across the patterning boundary are developed for super-resolution dual-wavelength additive manufacturing and insights into transport phenomena across the dual-wavelength projection boundary are gained. The nondimensionalized governing equations are derived as Volterra integral equations and solved using Picard iteration method to obtain photoinhibitor and monomer concentration profiles. This model elucidates the competition between photoinhibitor cross-termination rate constant and photoinhibitor radical diffusion. In addition, this model captures the time-dependent photoconversion profiles, photoinhibitor penetration depths, and arrival time. Using a calibrated degree of conversion threshold from experimental SEM image analysis, the model predicts the 3D printed pattern contours with root-mean-square error of 11.2%. The computation time of semi-analytical solution is 26.7 times faster than prior numerical method. Optimal experimental parameters including resin viscosity, exposure dosage, and design patterns are identified through parametric sweep based on two figures of merit: sharpness of conversion length scale and normalized curing width. This model provides a framework to understand reaction kinetics and patterning resolution within dual-wavelength additive manufacturing.