There are many reasons why adhesive bonds fail. Close examination of failed adhesive joints can usually lead to an explanation of why the bond failure occurred. The investigator's "tool box" for determining the cause of adhesive failures generally includes both inexpensive methods as well as state-of-the-art instrumentation. But, perhaps, the most important tools to use in the investigation are simple common sense and a predetermined, coordinated approach.
This article reviews (1) some of the general factors related to adhesive failures and (2) the steps to follow when conducting a failure investigation. There are generally four factors that contribute to failure of an adhesive bond.
* Selection of materials
* Joint design
* Processing
* Service conditions
Both the adhesive end-user and the formulator or supplier have responsibilities regarding these factors. The formulator must provide a product that is compounded with the correct materials for the application, and he or she must provide suitable instructions for joint design and processing of the product.