Catheter tip forming is processing the tip at the distal end so that catheter can move smoothly through the geometrically complex vascular structure. This thermoforming process has a problem in that the polymer tube adheres to the outer surface of the mold. To resolve this problem, previous researchers have coated the outer surface of the mold with PTFE (Polytetrafluoroethylene), which has a low coefficient of friction. However, due to repeated use, the coating is detached and the polymer tube adheres to the mandrels again, and the mold is frequently replaced. Thus, in this study, three types of metal were electroplated on the surface of the mold in to realize the performance of the PTFE coating. To select the optimal plating material, Cr, Zn, and Ni were selected as candidate groups. Surface energy, adhesion force, and abrasion depth & volume were measured for performance comparison. As a result, Ni, which has similar surface properties to PTFE, and the best durability, was selected as the optimal material. Based on these results, we present Ni-plated mold that can replace PTFE.

This study proposes a method for identifying correlations between tension and drop height for sessile droplets in a roll-toroll processing system. The effect of tension and drop height on the contact angle of a sessile droplet is presented. Design of experiment (DOE) methodology and statistical analysis are used to define a correlation between the process parameters. The contact angle is decreased while increasing tension and drop height. The influence of the tension is less significant on the contact angle compared with the effect of the drop height. However, tension should be considered as a major parameter because it is not easy to fix with roll eccentricity and compensating speed of the driven roll. The results of this study show that the effect of tension on the contact angle of a sessile droplet is more important than drop height because the drop height is fixed when the process systems are determined.