To improve medical device hole inner wall quality and overcome issues of traditional abrasive flow methods—limited fluidity in small holes causing deformation due to high inner wall pressure, and slow processing with low viscosity abrasives—a new method called shear thickening abrasive flow polishing is suggested. It uses shear thickening fluid as the medium. By leveraging the Preston equation and fluid dynamics theory, this study establishes both an abrasive flow dynamics model and a material removal model for the shear thickening abrasive flow machining of small titanium alloy hole workpieces in medical instruments. Utilizing the COMSOL software, the flow field state of shear thickening fluid within small holes is examined under varying flow behavior indexes and flow velocities. The findings demonstrate that shear thickening fluid yields superior polishing effects compared to Newtonian fluid. Elevating the flow behavior indexes facilitates a higher material removal rate on the inner wall surface; however, excessively large flow behavior indexes diminish the uniformity of material removal, thereby hindering the attainment of a high-quality polished surface. Furthermore, excessively large flow behavior indexes can reduce fluidity and consequently lower the efficiency of the polishing process. Conversely, while maintaining a constant flow behavior index, increasing the flow velocity contributes to an enhanced material removal rate and improved polishing efficiency. Nevertheless, as the flow velocity rises, the uniformity of inner wall surface roughness diminishes, posing challenges in achieving a high-quality polished surface.

Purpose: For the climbing rod object with large diameter variation and the need of obstacle crossing, this paper aims to propose a new embracing-type climbing robot named as EVOC-I robot. Design/methodology/approach: The design philosophy and structural scheme are introduced. The kinematic analysis of embracing and telescoping mechanisms is carried out to provide the theoretical foundation for the effective climbing of the robot. Based on the prototype robot, three preliminary experiments are carried out to verify the effectiveness of the designed robot. Findings: The theoretical and experimental analyses have verified the reasonability and effectiveness of the proposed robot design. Research limitations/implications: As the preliminary study, the prototype still need a lot of improvement. The experimental verification is also limited. Future work will focus on improving the design and increasing the theoretical analysis, especially increasing experimental study and designing the next generation of the rod climbing robot. Practical implications: The designed climbing robot can be used for climbing the rod with variation diameter and flange obstacle, especially the lightening rod in the transformer substation. Originality/value: The paper designs a new climbing robot that integrates the ability of large variation diameter adaptation and obstacle crossing.