5 Critical Questions to Ask About Pinch Testing Data

Posted by Josh Simon on Thu, Jan 26, 2012 @ 04:54

Pinch testing data can be used to make or break a lubricious hydrophilic coating.  It can also be used to lie.  When you see any graph depicting lubricity and durability for a coating, it is time to stop and take a breath before absorbing the data.  Ask yourself about the nature of the test used to get the information. 

pinch tester

Some hydrophilic coatings can be painted as amazingly slick and durable, but when put to a rigorous test, not so much.  Others shine and duke it out among the top.  I will soon be publishing a white paper demonstrating how differences in testing methods can make big variations in friction outcomes.  Below is a preview table of the 5 questions to ask yourself whenever you view friction data for a lubricious coating.

Question

Issue

For what Load does the current data display?

Tests using lower loads can give the appearance of a durable coating.

What is the pinch pad material used in the test?

Soft pinch pad materials are easier on the coating, and can portray favorable results.

What is the substrate material used in the test?

Soft substrates are easier on the coating, and can portray favorable results.

Was the test conducted under saline, pure water, or dry?

For medical devices, performance in saline is most clinically relevant, but dry or pure water performance can be used to artificially portray a coating in a positive or negative light, compared to actual in vivo performance.

How many cycles are displayed in the test data?

Low cycle numbers may not show a difference between two coatings, or be used to sidestep durability issues.

Tags: lubricious coating, medical device coating, pinch tester, medical device coatings, lubricious coatings, pinch testing, lubricity testing