Effect of the infill density on the performance of a 3D-printed compliant finger

Abstract

Recent advances in additive manufacturing and soft robotics have enabled the production of compliant fingers and grippers using 3D printing techniques. For instance, the fused deposition modeling (FDM) method allows users to print flexible filaments with pre-specified infill densities. In order to investigate the effect of the infill density on the performance of a 3D-printed compliant finger, this study performs experimental and numerical investigations in order to develop empirical equations for estimating the output force, the output displacement, and the input force corresponding to given values of the input displacement and infill density of the compliant finger. A commercially available thermoplastic elastomer (TPE) filament, Filastic™, manufactured by BotFeeder is used in this study. Prototypes of four compliant fingers with infill densities of 40%, 60%, 80%, and 100% are produced. A two-fingered gripper is also developed and the relationship between the infill density and the maximum payload is investigated. In addition, a finite element model taking into consideration the hyperelasticity of the TPE is developed to analyze the behavior of compliant fingers with different infill densities. The numerical results show good agreement with the experimental data and with the curves for the empirical equations.