Continuous 3D Printing-Induced Microparticle Distribution and Application

Digital light processing (DLP) three-dimensional (3D) printing has been considered one of the most sustainable additive manufacturing methods for high-speed and high-resolution construction. As 3D printing technology advances, a continuous printing process is achieved, which brings controllable parameters along with printing. Herein, we propose a refilling-driven particle redistribution mechanism during continuous printing, enabling the simultaneous control of microparticle distribution and 3D functionalization. The microparticle properties (dimension, wettability, and quantity ratio) and printing speed influenced the microparticle moving tendency and distribution law, which are versatile for different kinds of microparticles. Based on the single-microparticle distribution law, the motion of multidimensional microparticles along the resin refilling process can be controlled, through which microparticles can be controlled to locate inside different parts of the cured structure or inside the liquid resin. Selective microparticle separation from multidimensional mixed microparticles can be realized, with the special characteristics of small microparticle extraction from mixed microparticles. In addition, one-step printing of a two-dimensional (2D) or 3D wetting pattern can thus be realized by regulating the location of microparticles with different wettabilities and ratios. The 3D wetting patterns of the outer surfaces of structures and microfluidic inner surfaces can be one-step-printed, which satisfies the urgent demand for functionality beyond simple structural fabrication and expands the application scope of continuous 3D printing.