That’s the correct orientation though. 180 (squares on bottom ) puts the plus side of the led on the right. 90 (either way) puts the led contacts across all the pads creating a short.
Thank you all guys for the quick response. I knew something was not right and I thought posting a thread here would be the way to find out. I actually have the following three LEDs, XP-C, XT-E and XR-E. I found a Noctigon mcpcb for XP at mtnelectronics. That should work for the XP-C, right?
What about the XT-E and XR-E, where can I buy mcpcbs for those, preferably copper ones?
Careful telling people that it will work with Nichia emitters, without also telling them that the thermal pad will have to be ground out or covered over in order to not short out, since Nichia’s don’t have a thermal pad.
The xte will also fit but has a much higher thermal resistance so you won’t be able to drive it as hard. This Cree page has links to each of the Cree LEDs with data sheet PDF’s for each that include all the info. Pad sizing is located at the end of each PDF.
I’ve used a soup can lid. Anything will do that buffers the heat source and prevents the flux from seeing direct flame. I use a small butane torch now over 1/16” sheet aluminum for better control and so I can view it through my magnifying lamp.
XTE fits XPG pads, XRE copper stars aren’t made but you might be able to sit one on an mtg star. The mtg pads are similarly spaced but longer in length so the XRE might not self center.
At least a XR-E fits on a MT-Noctigon copper board, but it does not profit much from the fancy copper board because it sheds the heat well enough on a convential aluminium board (I tested that).
But why using a XR-E? There is nothing about it that is not better in more modern leds.