Research on the Comparison Properties of PDMS Specimens Demolding Processes and the Mechanical Performance of Hollow-Solid Ratios of Flexible Telescopic Rods

Abstract

The main motivation of this work was to demonstrate a hollow telescopic rod structure that could be used for minimally invasive surgery. The telescopic rods were fabricated using 3D printing technology to make mold flips. During fabrication, differences in biocompatibility, light transmission, and ultimate displacement were compared between telescopic rods fabricated via different processes, so as to select the appropriate process. To achieve these goals, flexible telescopic rod structures were designed and 3D-printed molds were fabricated using Fused Deposition Modeling (FDM) and Stereolithography (SLA) techniques. The results showed that the three molding processes had no impact on the doping of the PDMS specimens. However, the FDM molding process had lower surface flatness accuracy compared to SLA. The SLA mold flip fabrication exhibited superior surface accuracy and light transmission compared to the other methods. The sacrificial template method and the use of HTL direct demolding technique had no significant impact on cellular activity and biocompatibility, but the mechanical properties of the PDMS specimens were weakened after swelling recovery. The height and radius of the hollow rod were found to have a significant impact on the mechanical properties of the flexible hollow rod. The hyperelastic model was fitted appropriately with the mechanical test results, and the ultimate elongation increased with an increase in hollow–solid ratios under the uniform force.