Additive manufacturing of pneumatically actuated soft robotic grippers: enabling complex geometries and configurations

This paper presents the design, fabrication, and testing of a pneumatically actuated soft gripper manufactured via multimaterial 3D printing (FDM), combining flexible TPU 40D segments with PLA structural elements for stiffening and modular assembly. The biomimetic geometry – drawing inspiration from the segmented locomotion of caterpillars – integrates three “fingers” with internal pneumatic channels and partially fused chambers, optimized to deliver controlled elastic deformation while meeting AM design constraints (minimum wall thicknesses, overhang angles ≥ 45°, and avoidance of long unsupported bridges). The fabrication strategy included mid-print PLA inserts for anchoring, sliding-fit gaps of 0.05–0.15 mm, and a teardrop-shaped internal channel to minimize unsupported spans and improve process repeatability. Preliminary tests showed (i) a smooth and predictable bending response of a single finger at ≈ 1–3 bar, validating the material choice and chamber configuration, and (ii) reduced performance of the three-finger assembly due to air leaks at the interfaces, underscoring the importance of sealing and robust pneumatic distribution. Improvement directions include the use of O-rings/gaskets, fine pressure regulation, and integration of sensors for closed-loop control. The results indicate that 3D-printed soft grippers can combine adaptability, customization, and cost efficiency for delicate manipulation, paving the way for industrial and medical applications where safe interaction with fragile objects is critical.