Cree UV LEDs domes falling off

Hi, I'm working on an LED array that has 6 Cree UV Xlamps. The dome on one of the LEDs just fell right off. After closer inspection of the other 5, they are all loose and move around when you touch them lightly.

First of all, is this a defective batch or is this just how Crees are? I've been working with Luxeons and Lamina Ceramics Atlas LEDs and have not had any issues with them. They haven't been handled roughly but were placed upside-down on a towel while I was working on the heat sinks.

Second, is there any way to remedy the situation? I have all six epoxied to heat sinks and soldered in and it would be a pain to remove them, and also expensive to replace. Is there a sealant I can use for the 5 that are loose but haven't come off yet? What about a little bit of thin CA glue around the base of the dome? Is the one that's completely fallen off ruined now that its exposed to air? They all light and the beam may be ok since these are being used without optics or reflectors.

Could be a bad batch of adhesive holding it on, rough handling during shipping, heat related, could be a number of things, did they fall off or did you pull it off?

The one that fell of did so on its own after I flipped the heatsink upside-down. I guess I'll call Cree and talk to them about it.

The guy I talked to at Cree basically told me not to touch the domes at all when I working with them. I'm going to try to glue them using some silicone adhesive. The next batch I order I'll be sure to check them before I do anything with them, since I'm not sure if they came like that.

maybe in a major Cree brainfart, the adhesive is UV sensitive.:laughing:

The Cree rep did say they're designed so that the dome can expand as they heat. That seems like it would change the beam pattern though.

If they are UV sensitive thats not the problem with mine since they've only had juice running through them for a few seconds so far.

They may be faulty, it looks like the adhesive has broken down or wasn't applied correctly