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.
Cazacu et al. (Mon,) studied this question.