So I got a couple 20mm XM-L Noctigons today, and they didn’t feel quite right. It felt like the heat pad was raised. I grabbed a small machinist’s square (that’s REALLY flat) and went over to my stereo microscope that can be bottom lit. At 30X, clearly one of the Noctigon’s heatpads was raised a little, but it was flat and parallel to the general surface. I think a little extra solder paste on the electrical contacts would fix that. But the other one was raised maybe .005”, and it was a hump—no way would an LED sit flat on that. It would lean to one side or the other. I would not mount a LED on this without lapping it first.
So, is a mound-shaped raised thermal pad a problem or a feature?
I have 2 16mm XMs and 1 MT-G blank Noctigons, and they are nice and flat—even at 30X.
How flat should look when lit from below: Sorry about the picture size. I changed them to 800 X 600 in Photobucket, but it didn’t seem to stick.
The other side:
