A heat sink should last for decades
yes it should , but when a led lightbulb with an alu heatsink fails, that heatsink will be the wrong size and shape to be fitted in another led lightbulb, so it will unfortunately need smelting back down.
This is not an acceptable use of energy....and can be avoided by not using aluminium heatsinks, but instead using large led pcbs with enough cooling copper to cool the multiple low-power leds.
These led pcbs, when they fail, they can just have the leds desoldered and then fresh leds soldered back on again.
vvv
Is there anything intrinsically wrong with this thread?.....I posted a similar thread on a different forum, and very politely explained the whole purpose, and yet it was hotly rebuked, and after 49 threads, that forum deleted all 49 threads.
The purpose of this product is to do domestic mains lighting with repairable LED lightbulbs...so that no glass gets thrown away like it does with CFLs (since not all of them get returned to the CFL collection points).
We also want to avoid aluminium heatsinks, as these just end up getting smelted back down when the bulb dies...this is a waste of energy.
vvv
One other reason to use many small leds (& no alu heatsink), instead of a few bigger power leds (but with an alu heatsink), is that bigger power leds comprise a central thermal pad which would be difficult to hand solder when the LED PCB is being repaired after its lifetime use. (you can see the thermal pad on page 14 of the golden dragon datasheet)....
Osram golden dragon 3W power led:
http://catalog.osram-os.com/catalog...=downloadFile&favOid=0200000200039541000200b6
...you see, in the other forum where this whole idea was rebuked, they seemed to think that it would be best to simply use an alu heatsink, of a standard size, and literally re-use that heatsink. -That all sounds very well, however, firstly, how are we going to make multiple private companies come together and agree on one (or a few) standardised heatsink shapes? Also, as just mentioned, if an alu heatsink is used, then we'll obviously be using a few small, higher power leds, (since the heatsink is there), and thus the problem with desoldering and re-soldering leds to the PCB when the LED PCB eventually fails and needs repair (due to the difficulty of hand soldering the thermal pad)
Anyway, this whole idea of repairable domestic mains lightbulbs was quite viciously rebuked in a different forum....there were 49 posts in the thread, where the idea was passed off as almost lunacy, then they deleted the entire thread, and banned me from the forum. Is this idea that bad?
In that (now extinct) thread, I mentioned that the repairable bulb was LED based, and at least LED bulbs don't contain mercury, but this was rebuked, and their forum members told me that 20 cans of tuna contains as much mercury as one CFL.....so , they said, "just don't *eat* CFLs or tuna". I knew that the mercury_in_CFLs problem was not that bad, but I didn't know it was that insignificant?