Produce an utra smooth "glass like" surface finish
The low shrink temperature and high melt temperature of polyester heat shrink tubing
enables it to be used very effectively to form smooth tapered tips on the ends of
catheters and other medical devices. In the initial operation, a section of heat
shrink tubing is slid onto the end of a catheter tube, leaving a tail off the end.
A coated metal rod or PTFE beading is inserted in the catheter to maintain the tip
ID. Heat is then applied to shrink the tubing onto the substrate, causing the
substrate to melt and flow. Pulling on the heat shrink tube draws the catheter tube to
a very thin, smooth tip. Since the shrink tubing is clear, the operator can monitor
the process. The shrink tubing is removed to complete the job, leaving an ultra smooth
finish.
In catheter tip forming, clear polyester heat shrink tube is first attached
to the end of a catheter tube, then more heat is applied (with hot air torch extending
from background), while a hemostat (at right) is used to pull and draw the shrink
tube, forming a smooth tapered tip. A mandrel is used to prevent the tip I.D. from
collapsing during the process.