Fabrication of Flexible Multi-Cavity Bio-Inspired Adhesive Unit Using Laminated Mold Pouring

To meet the requirements for the flexible end-effectors of industrial grippers and climbing robots, inspired by the animal attachment mechanism, a bio-inspired adhesive unit (Bio-AU) was designed. Due to its fluid-driven operating characteristics and multi-level adhesive structure, its fabrication and molding is challenging, including the assembly and molding of complex cavities with good pressure-bearing capability, mechanical properties of multi-level materials with variable stiffness, etc. In this study, based on the lamination mold casting process, the simultaneous molding and assembly method was established, which can be applied to form and assemble complex cavity parts simultaneously. Moreover, the dovetail tenon-and-mortise parting structures were analyzed and designed. Furthermore, the adhesion between the parting surfaces can be improved using plasma surface treatment technology. By applying the above methods, the assembly accuracy and pressure-bearing capability of the complex flexible cavities are improved, which reduces the individual differences between finished products. Additionally, the maximum pressure-bearing value of the sample was 83 kPa, which is 1.75 times that before optimization. the adhesive structure with different stiffness components was fabricated at low cost using silicon rubber substrates with different properties, which met the requirements of multi-level material with variable stiffness of the Bio-AU. The bending angle of the optimized molding product was about 50.9 degrees at 80 kPa, which is significantly larger than the 24.6 degrees of the lighting-cured product. This indicates that the optimized lamination mold casting process has a strong inclusion of materials, which improves the deformation capacity and self-adaptability of Bio-AUs and overcomes the defects of 3D printing technology in the formation of large, flexible, and controllable-stiffness structures. In this study, the effective fabrication of flexible multilayer adhesive structures was accomplished, and technical support for the development of Bio-AUs was provided, which met the requirements of bionic climbing robots and industrial adhesive grippers for end-effectors.

Automated summary

In this study, a bio-inspired adhesive unit (Bio-AU) was designed inspired by the animal attachment mechanism to meet the requirements for flexible end-effectors of industrial grippers and climbing robots. The fabrication and molding of the Bio-AU, with its fluid-driven operating characteristics and multi-level adhesive structure, present challenges including complex cavity assembly and molding, variable stiffness of materials, etc. Through the lamination mold casting process and plasma surface treatment technology, the simultaneous molding and assembly method was established to improve the assembly accuracy and pressure-bearing capability of the complex flexible cavities. Additionally, the fabrication of the adhesive structure with different stiffness components using silicon rubber substrates with different properties was achieved at low cost.