Reducing Interfacial Separation Force in High‐Speed Constrained‐Surface Projection Stereolithography Using a Dual‐Modulus Silicone Release Film

ABSTRACT Reducing interfacial separation force is a challenge in constrained‐surface projection stereolithography (SLA), where excessive detachment forces cause print instability, surface defects, and delamination. Although auxiliary strategies can decrease separation force, they introduce system complexity and limit industrial adoption. In this study, a dual‐modulus silicone release film (DMSRF) is proposed to regulate interfacial separation through modulus‐mismatch‐induced stress localization. The DMSRF consists of periodically distributed low‐modulus silicone domains embedded in a high‐modulus silicone matrix, creating distributed stress‐concentration sites at the resin–film interface. Finite element simulations reveal that this heterogeneous architecture localizes tensile stress around the low‐modulus domain boundaries, thereby promoting distributed crack initiation during separation. Experimental results show that the DMSRF reduces the peak separation force from 9.684 N for a commercial fluorinated ethylene propylene (FEP) film to 0.237 N, while shortening the detachment time from 1.7 to 0.6 s. Benefiting from the reduced separation force, stable continuous printing was achieved at 720 mm h −1 without auxiliary devices or interfacial lubricants, while maintaining good printing accuracy and low mechanical anisotropy. This work demonstrates that rationally designed modulus heterogeneity provides an effective interfacial engineering strategy for reducing separation force, expanding the processing window, and improving the reliability of constrained‐surface projection SLA.