First-time-right printing of compliant mechanisms manufactured with standard Laser Powder Bed Fusion process parameters: an investigation of the impact of manufacturing defects on the stiffness of thin structures.

Compliant mechanisms achieve motion through elastic deformation of slender blades, offering high precision and eliminating issues such as friction, backlash, and lubrication needs, making them particularly attractive for space scientific instrumentation applications. While Additive Manufacturing (AM), particularly Laser Powder Bed Fusion (LPBF), enables the fabrication of such monolithic structures, their performance is highly sensitive to manufacturing defects. As such, their manufacturing traditionally requires a resource-intensive optimization of the LPBF process. In this study, we model the impact of surface roughness, surface offset, and internal porosity on the as-built stiffness of Ti-6Al-4V cantilevers. Based on scanning electron microscopy of five representative samples, we developed a high-fidelity predictive model that estimates stiffness with a mean error of 3.31% across 43 samples (standard deviation: 4.99% Building on this model, we introduce a preventive correction strategy that adjusts nominal geometry to achieve target stiffness values. This approach was validated on 15 corrected samples, achieving a mean error of just 1.32% . Finally, we extended the methodology to more complex systems - a cross-axis flexural pivot and a 2-DOF compliant pointing mechanism - demonstrating similar accuracy under alternative loading conditions These results confirm that our strategy enables first-time-right printing of compliant mechanisms using standard LPBF parameters, making functional AM accessible even without extensive process optimization.