Medical Catheters and Plastics – Part VII

In our previous article, we explored the stages of material drying and extrusion in the manufacturing process of medical catheters. Building on that discussion, this article will focus on a critical element within the extrusion process: the flow of the melt through the tubing die. We will delve into the factors related to die design that influence this process.

The flow characteristics of the material, along with its correlation to shear and temperature, can be precisely assessed through rheological studies. Consequently, it is essential to examine the rheology of the polymer before utilizing it as a catheter material and choosing a specific screw design. This approach will guarantee that the plastic is extruded under appropriate conditions, resulting in a final catheter with optimal physical properties.

An extruder die is positioned at the end of the extruder, shaping the initial form and dimensions of the extruded tube. The tubing die comprises two primary components: a mandrel or pin that creates the tube's inner diameter (ID), and a die that shapes the tube's outer diameter (OD). Together, the die and the mandrel make up the extrusion head. Various designs of dies, heads, and mandrels exist, and these designs are crucial in the extrusion process, significantly influencing the capability to produce tubes with precise dimensions.

Click here to read full article