Adhesives Industry Guide for Universal Testing Machines
Adhesives and Pressure Sensitive Tapes can be tested using a number of different ASTM procedures. Each procedure usually requires a different type of grip or peel fixture. Along with tapes, adhesive epoxies and resins can also be tested by means of a lap shear test.
The Galdabini line of universal testing machines is highly customizeable and can perform virtually every type of mechanical test related to adhesives. The advanced Graphwork 6 software is used to both control the machine during test, but also to calculate the measurements and generate reports.
Average Peel Strength - Peel Strength is the most popular measurement taken for Pressure Sensitive Adhesive (PSA) tapes. The measurement is calculated using the Graphwork 6 analysis package. The first few inches worth of data are discarded as well as the last few inches. The peel strength unit is then given by the load/tape width. Most tapes are tested using a sample width of 1 inch.
Peak and Low Peel Strength - Along with the average peel strength, the peak load and lowest load are also usually recorded on the test report.
How to Configure a Universal Testing Machine for Peel Testing
Specifying a peel testing machine is relatively simple. Almost every ASTM adhesive testing procedure can be performed on a standard single column 500lb or 2.5kN Galdabini Quasar. Universal Grip is one of the few companies that holds stock inventory of both tensile testing systems and the associated necessary grips for peel testing. For a complete list of our in stock items, please visit our Inventory page.
Introduction to ASTM Testing for Adhesives
ASTM D1002 - Lap Shear Testing - involves adhering two metal based materials together using an epoxy or other type of permanent bonding adhesive. 2 Wedge Grips are used to secure the metal sample ends. Careful attention must be made to the alignment of the sample, and sometimes a universal joint or a cardan joint may be used in order to align the uniaxial force.
ASTM D6862 - 90 Degree Peel Testing uses a special 90 degree peel fixture to maintain the 90 degree angle throughout the test. There is a cable for the pulley system that must be mounted behind the load cell in order to not interfere with the load measurement of the peel strength. The 90 degree peel is test will tend to show the weakest results for peel strength when compared to the 180 degree peel test and the T-peel or trouser test.
ASTM D3330 - 180 Degree Peel Testing is one of the most common types of test because it is a little easier to set up compared to the 90 degree peel test. The peel stage material can be switched out and be either glass or metal.