Ultraviolet-Follow Curing-Mediated Extrusion Stabilization for Low-Yield-Stress Silicone Rubbers: From Die Swell Suppression to Dimensional Accuracy Enhancement

Direct ink writing (DIW) of low-yield-stress UV-curable silicone rubber faces challenges in maintaining dimensional accuracy due to post-extrusion swelling and viscoelastic deformation. This study proposes an ultraviolet-follow curing (UFC) method to enhance geometric precision by UV-follow curing (UFC) during deposition. The effects of UFC on filament dimensions—including width, length, cross-sectional geometry, and roundness—were systematically investigated. The mechanical properties of the printed structures were also evaluated to assess their functional integrity. The experimental results demonstrated that UFC effectively reduced extrusion swelling, achieving a filament-width deviation reduction of 22–81% and a filament-length deviation of 1.4–1.8% compared to conventional DIW. The printed rings exhibited improved roundness uniformity with reduced geometric fluctuations. Crucially, UFC enhances dimensional accuracy without compromising the mechanical performance of low-yield-stress silicones, providing a viable strategy for the high-precision additive manufacturing of soft elastomeric architectures.