Design and experimental study of a cross-spring flexure hinge based on metal additive manufacturing

In this paper, a cross-spring flexure hinge is designed. The hinge comprises two leaf springs arranged in a cross configuration, with movement achieved through elastic deformation of the springs. By analysing the series-parallel relationship of the individual segments, an equivalent rotational stiffness model was established based on the elastic beam theory. Finite element simulations were conducted to evaluate the rotational stiffness, revealing that among the four design parameters, leaf thickness t, intersection hole edges a and b, and intersection angle α, the leaf thickness t has the most significant influence. Furthermore, three types of flexure hinge samples were manufactured using selective laser melting with AlSi10Mg, TC4, and 316L materials. Experimental results indicated that 316L provided the closest match to the simulated stiffness, with an average error of 2.34%. However, its high density limits its suitability for lightweight applications. TC4 demonstrates the best overall performance, balancing mechanical performance, print quality, and lightweight requirements. This research provides a valuable reference for the engineering design, material selection, and manufacturing process optimization of flexure hinges.