 Nadine Blaesing Dymax Corp. Market Segment Manager Visit Website |
Nadine Blaesing is the market segment manager, Europe, for Dymax. She has more than 12 years of experience selling adhesives and providing technical assistance to the medical device market. Although she began her career as an applications engineer in Europe, and later in the United States, Blaesing eventually transitioned into marketing while keeping her focus on the medical device industry. Dymax specializes in the manufacture of light-curable adhesives, cyanoacrylates, epoxies, light-emitting curing equipment, and dispensing systems.
|
Adhesives and Epoxies Q&A
-
We are using a UV-light-curable adhesive to bond a polycarbonate hub to a passivated stainless-steel hypotube. We encountered a leakage issue during our in-process air-leak test. Confirmation of the leak happened at the interface between the adhesive and the hypotube when a colored dye was injected. Prior to the dye injection, we could see “delamination” between the parts. We tried applying a primer on the hypotube, wiping the hypotube with IPA, and performing a longer curing time. However, these steps did not help to eliminate the delamination. What do you suggest is the cause and remedy?Answered January 26th, 2011 by Expert:If contamination has been ruled out, delamination is most likely related to uneven stresses within the adhesive joint. I suggest that you look at the adhesive choice, viscosity, bond gap, and curing process.
Is the adhesive and its viscosity appropriate for this application and the bond gap? UV-light-curing adhesives shrink during the curing process and may pull away from the surface to which they have less adhesion. The larger the bond gap, the more likely we will see air bubbles or delamination. In such cases, I would try an adhesive with less shrinkage or a filled, higher-viscosity adhesive. Suitable products from Dymax are 1180-M and 1180-M-T-UR, which is the higher-viscosity version for larger bond gaps.
You mentioned that you tried a longer curing time. Did you also explore curing with different intensities? I would recommend that you try a shorter light exposure at a higher intensity and a longer exposure at a lower intensity.
Do you cure the adhesive from the top or from the side? If you cure from the side and use a UV spot lamp equipped with one or two light guides, there is a risk of introducing uneven stress due to the shrinkage of the adhesive. The areas not directly exposed to the light often exhibit delamination, or you see air bubbles in the bond joint. In such cases, I would recommend that you use a three- or four-splitted light guide instead.