Design and Analysis of Additive Manufactured Flexure Hinge with Large Stroke and High Accuracy

Additive manufacturing technology has significant potential for the development of advanced compliant mechanisms for precision manipulations owing to the advantage of realizing complex monolithic structures. By overcoming the limitations of traditional manufacturing technologies, this study develops a novel spatial spiral-based flexure hinge that aims to have a large stroke and high accuracy. In particular, the ∞-shaped configuration was adopted along the width direction of the flexure hinge by adjusting the spiral diameters. Owing to the excellent deformation capability and geometric constraints of the spatial spiral structure, the developed flexure hinge is capable of deflecting up to 90° with a small axis drift. The stiffness model of the flexure hinge was derived based on the elastic beam theory to illustrate the load–deflection relationships. The characteristics of the flexure hinge were further verified by finite element simulations and experiments on an additive manufactured prototype. Compared with the traditional flexure hinge, the developed design demonstrates a higher range and accuracy of rotation and a better ability to preserve the rotation center position but smaller compliance, which demonstrates a significant potential for emerging applications, including optical adjustments, biomedical operations, and robot joints.