UV-curing kinetics and performance development of in situ curable 3D printing materials

As three-dimensional (3D) printing technology is emerging as an alternative way of manufacturing, the high resolution 3D printing device often requires systems such as drop jetting printing of in situ UV-curable photopolymers. Accordingly, the key issue is process control and its optimization to ensure dimensional accuracy, surface roughness, building orientation, and mechanical properties of printed structures, which are based on the time- and temperature-dependent glass transition temperature (T_g) of the resin system under UV-curing. In this study, the UV-cure kinetics and T_g development of a commercially available UV-curable acrylic resin system were investigated as a model system, using a differential scanning photocalorimeter (DPC). The developed kinetic model included the limited conversion of cure that could be achieved as a maximum at a specific isothermal curing temperature. Using the developed model, the T_g was successfully described by a modified DiBenedetto equation as a function of UV curing. The developed kinetic model and T_g development can be used to determine the 3D printing operating conditions for the overlay printing and in situ UV curing, which could ensure high-resolution and high-speed manufacturing with various UV-curing materials.