Improved thermal management for ARC LS

[PeterB]

From my point of view the two main weaknesses of the ARC LS are the thermal transfer from the circuit/LED board to the housing and the optics mounting.
The heat transfer to the Alu disc is pretty good, but there are three interfaces from this disc to reach the body. I have observed, that the positive contact gets quite hot, which is probably caused by the limited heat transfer.

The other weakness is that the optics is directly pressed onto the emitter. This can lead to a leakage of silicone and farkle and makes the centering difficult and an optics spacing to improve the beam pattern impossible.

I have tried to fix this two points by potting an Al tube to the circuit board. This tube improves the thermal transfer to the body and is also used as optics holder.

Here are some images:

It worked really well. It is possible to center the optics outside the light and fix it with some drops of epoxy. The board stays also much cooler.

 

[Nerd]

You're going to start offering these alu tubes to modders or what? /ubbthreads/images/graemlins/naughty.gif

/ubbthreads/images/graemlins/thumbsup.gif

 

[shiftd]

ditto /ubbthreads/images/graemlins/grin.gif

looks nicee !!!

 

[flashlight]

I need one of those too /ubbthreads/images/graemlins/grin.gif

 

[Christoph]

At least can we have some dimensions please /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/thumbsup.gif
Chris

 

[Kiessling]

oh ... nice! you really should deliver those to the guys modding our Arcs!
Arc LS still rules!
bk

 

[PeterB]

I have used a tube with 20mm outer diameter and 1mm wall thickness. The height is around 12 mm.
I have found a web shop in germany, which sells small amounts of Al material (www.alu-verkauf.de), but I assume there are even more possibilities in the US.

It is necessary to reduce the diameter slightly to about 19.85mm .. 19.9mm to fit into the body.

This is my procedure:
- Reduce the diameter to fit the body (with a grinding machine or file)
- File down the length (with one or two mm margin)
- Remove some material near the inductor to avoid shorts
- Pot the tube to the board with arctic aluminium
- File down the tube (and add cut for optic tab)until beam is ok (file and dremel)
- Center and fix the optics
- Install the resulting module with some thermal compound.

If there is interest, I could of course send some tubes.
Either the raw tubes, or grinded down to 19.9mm.
But the fine adjustment to the optics should be done after potting.
But I think it is very easy, to get such simple Al tubes.

One more improvement idea, which is far beyond my possibilities: It would be ideal to have an outer thread, fitting to the ARC body. This would improve the thermal transfer further and installation would be also easier.

 

[Ralf]

/ubbthreads/images/graemlins/thumbsup.gif

I think I should try this the next time opening
my ARC ...

Cheers
Ralf

 

[cgpeanut]

Great Mod PeterB! /ubbthreads/images/graemlins/thumbsup.gif I'm going to try this mod (as soon as I find the al tube) on an IMS reflector by cutting the fins off with a nail clipper, hopefully it would take some stress out of the luxeon emiiter spread it around the al tube instead.