Max targets precise bonding in optical applications in his latest Tech Talk. He introduces EP42HT-2LTE, a two part epoxy with an exceptionally low coefficient of thermal expansion, superior dimensionally stability and a high strength profile.
Olivia: Hi Max. This is Olivia from Optics R Us.
Max: Hi Olivia. It's great to hear from you. What can I do for you today?
Olivia: I’m calling about a bonding application for an optical assembly. We’re using glass and ceramic based substrates. Since these materials have a low coefficient of thermal expansion, we need an adhesive that offers low shrinkage, a low CTE, and a rigid cure. You should also be aware that precise alignment of these materials, post cure, is critical. The adhesive must have minimal flow due to the geometry of the components.
Max: I see. What have you tried so far?
Olivia: We were using a highly flexible adhesive and found that there was some movement post cure, so precise alignment was not achieved. This could have resulted from temperature fluctuations. Not only that, the material flowed too much for us to control the alignment prior to cure.
Max: Are there other performance properties that are important?
Olivia: Yes, the bond must offer good strength, as well as superior dimensional stability. Max, what would you recommend?
Max: EP42HT-2LTE is an innovative epoxy with an ultra low coefficient of thermal expansion. After mixing, the consistency is that of a paste with some flow. It also has several other properties that you mentioned. I think it would work well.
Olivia: Hi Max. Great news. After using EP42HT-2LTE, we successfully attained a very rigid, dimensionally stable bond with an extremely low CTE that closely matched our substrates. That seemed to solve the alignment issue. The epoxy maintained alignment during temperature fluctuations tests. The thick paste like consistency solved the flow problem. Finally, we realized much better mechanical strength than we did with the flexible adhesive.
Max: That is great news Olivia. I’m so glad we were able to improve your optical bonding application. If you have more applications, please call us.