An Experimental Study on the Dynamic and Thermal Behaviors of Colloidal Droplet in a Freezing-Based Inkjet 3D Printing Method

Inkjet-based 3D printing is extensively utilized; however, this technology encounters several critical challenges, including coarse resolution, inadequate adhesion, and inconsistent manufacturing. A key factor contributing to these challenges is that the colloidal suspension droplets remain in a liquid state during the printing process. To overcome these limitations, we propose an innovative freezing-based sublimation 3D printing technology. Experiments will be conducted with both sessile and jetting droplets on a subfreezing substrate. The droplet dynamics and freezing process will be recorded using a high-speed imaging system, while temperature variations across the droplet diameter will be captured by an infrared thermal imaging system. Following freezing, the sample will be transferred to a freeze dryer for sublimation. Two thermodynamic processes have been designed to achieve sublimation: Process A involves a vacuum at a constant sub-freezing temperature, and Process B involves heating at a constant low pressure. In both processes, it is anticipated that the droplet will undergo sublimation successfully and continuously. The designed experiments and their results will analyze the mass and heat transfer during the freezing and sublimation processes, correlating the freezing rate and sublimation rate with various deposition morphologies. Through this comprehensive process, we aim to significantly enhance the stability and resolution quality of the printing.