Wrong Adhesive for the Application
When all other options have been exhausted, it may be that the adhesive selected for an application is simply a poor choice relative to the performance characteristics required. This problem may seem unlikely to occur in a production environment; however, devices are often used in more strenuous conditions than those for which they were originally qualified. Single lot testing of an adhesive may have failed to identify lot to lot variance in key properties that can affect device performance. In addition, factors that are critical to actual use performance may have been overlooked during the qualification process.
Determining which category an adhesive failure falls into and reviewing the potential causes and solutions for that type of failure should assist in resolving bond failure problems when bonding plastics with cyanoacrylates and light curing acrylic adhesives. Considering the potential sources of adhesive bonding problems up front will aid in developing more robust adhesive bonding processes. In cases that cannot be solved using this methodology, it is suggested to involve the adhesive supplier. The supplier’s experience and detailed knowledge of their specific formulations can often allow them to identify the key parameters that will spell the difference between success or failure.