Mechanism of Separation Force Behavior and Interface Optimization in Vat Photopolymerization: An Energy-Based Perspective

The vat photopolymerization technology is widely employed in additive manufacturing due to its high printing accuracy and rapid fabrication speed. However, the layer-by-layer curing process of the bottom-up vat photopolymerization method inherently generates significant separation force, which occurs during the detachment of each cured layer from the interface, often leading to structural failure or printing defects. The regulation of exposure energy during the printing process critically influences the magnitude of the separation force. However, the underlying mechanism governing the relationship between the exposure energy and separation force remains insufficiently understood. To address this, the present study systematically investigates the behavior of the separation force under varying exposure energies and elucidates the mechanism through an adhesion energy equilibrium analysis. Furthermore, an effective interface optimization strategy─hollow air film─is proposed. This strategy reduces the adhesion energy contact area through a flexible peeling mechanism, thereby significantly lowering the separation force. This research provides fundamental insights into the regulation of exposure energy and separation force in vat photopolymerization, offering crucial advancements for enhancing printing quality and process efficiency.