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.